Boost Azure Demo

2026-05-25 17:05:06 +01:00
parent 675285e99d
commit 4f79137d89
230 changed files with 43275 additions and 2644 deletions
--- a/Backend/db/embed.go
+++ b/Backend/db/embed.go
@@ -0,0 +1,6 @@
+package db
+
+import "embed"
+
+//go:embed migrations/*.sql
+var Migrations embed.FS
--- a/Backend/db/migrations/001_init.sql
+++ b/Backend/db/migrations/001_init.sql
@@ -0,0 +1,160 @@
+-- +goose Up
+CREATE TYPE user_role AS ENUM ('student', 'teacher');
+CREATE TYPE question_status AS ENUM ('draft', 'published', 'archived');
+CREATE TYPE assignment_status AS ENUM ('draft', 'assigned', 'closed');
+CREATE TYPE answer_status AS ENUM ('not_started', 'in_progress', 'submitted', 'reviewed');
+
+CREATE TABLE users (
+    id BIGSERIAL PRIMARY KEY,
+    email VARCHAR(255) NOT NULL UNIQUE,
+    password_hash TEXT,
+    role user_role NOT NULL,
+    full_name VARCHAR(255) NOT NULL,
+    is_active BOOLEAN NOT NULL DEFAULT TRUE,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE classrooms (
+    id BIGSERIAL PRIMARY KEY,
+    teacher_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    name VARCHAR(255) NOT NULL,
+    code VARCHAR(50) UNIQUE,
+    description TEXT,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE classroom_students (
+    classroom_id BIGINT NOT NULL REFERENCES classrooms(id) ON DELETE CASCADE,
+    student_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    joined_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    PRIMARY KEY (classroom_id, student_id)
+);
+
+CREATE TABLE questions (
+    id BIGSERIAL PRIMARY KEY,
+    author_teacher_id BIGINT NOT NULL REFERENCES users(id) ON DELETE RESTRICT,
+    title VARCHAR(255) NOT NULL,
+    prompt TEXT NOT NULL,
+    subject VARCHAR(100),
+    source TEXT,
+    status question_status NOT NULL DEFAULT 'draft',
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE tags (
+    id BIGSERIAL PRIMARY KEY,
+    name VARCHAR(100) NOT NULL UNIQUE,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE question_tags (
+    question_id BIGINT NOT NULL REFERENCES questions(id) ON DELETE CASCADE,
+    tag_id BIGINT NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
+    PRIMARY KEY (question_id, tag_id)
+);
+
+CREATE TABLE assignments (
+    id BIGSERIAL PRIMARY KEY,
+    classroom_id BIGINT NOT NULL REFERENCES classrooms(id) ON DELETE CASCADE,
+    teacher_id BIGINT NOT NULL REFERENCES users(id) ON DELETE RESTRICT,
+    title VARCHAR(255) NOT NULL,
+    instructions TEXT,
+    status assignment_status NOT NULL DEFAULT 'draft',
+    due_at TIMESTAMPTZ,
+    published_at TIMESTAMPTZ,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE assignment_assignees (
+    assignment_id BIGINT NOT NULL REFERENCES assignments(id) ON DELETE CASCADE,
+    student_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    assigned_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    PRIMARY KEY (assignment_id, student_id)
+);
+
+CREATE TABLE assignment_questions (
+    assignment_id BIGINT NOT NULL REFERENCES assignments(id) ON DELETE CASCADE,
+    question_id BIGINT NOT NULL REFERENCES questions(id) ON DELETE RESTRICT,
+    position INTEGER NOT NULL,
+    PRIMARY KEY (assignment_id, question_id),
+    CONSTRAINT assignment_questions_assignment_position_key UNIQUE (assignment_id, position)
+);
+
+CREATE TABLE student_answers (
+    id BIGSERIAL PRIMARY KEY,
+    assignment_id BIGINT NOT NULL REFERENCES assignments(id) ON DELETE CASCADE,
+    question_id BIGINT NOT NULL REFERENCES questions(id) ON DELETE RESTRICT,
+    student_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    answer_text TEXT,
+    ai_feedback TEXT,
+    teacher_feedback TEXT,
+    status answer_status NOT NULL DEFAULT 'not_started',
+    submitted_at TIMESTAMPTZ,
+    reviewed_at TIMESTAMPTZ,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    CONSTRAINT student_answers_assignment_question_student_key UNIQUE (assignment_id, question_id, student_id)
+);
+
+CREATE INDEX idx_users_role ON users(role);
+CREATE INDEX idx_classrooms_teacher_id ON classrooms(teacher_id);
+CREATE INDEX idx_questions_author_teacher_id ON questions(author_teacher_id);
+CREATE INDEX idx_questions_status ON questions(status);
+CREATE INDEX idx_assignments_classroom_id ON assignments(classroom_id);
+CREATE INDEX idx_assignments_teacher_id ON assignments(teacher_id);
+CREATE INDEX idx_assignment_assignees_student_id ON assignment_assignees(student_id);
+CREATE INDEX idx_student_answers_student_id ON student_answers(student_id);
+CREATE INDEX idx_student_answers_assignment_id ON student_answers(assignment_id);
+
+-- +goose StatementBegin
+CREATE OR REPLACE FUNCTION update_updated_at()
+RETURNS TRIGGER AS $$
+BEGIN
+    NEW.updated_at = NOW();
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+-- +goose StatementEnd
+
+CREATE TRIGGER users_updated_at BEFORE UPDATE ON users
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER classrooms_updated_at BEFORE UPDATE ON classrooms
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER questions_updated_at BEFORE UPDATE ON questions
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER assignments_updated_at BEFORE UPDATE ON assignments
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER student_answers_updated_at BEFORE UPDATE ON student_answers
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+-- +goose Down
+DROP TRIGGER IF EXISTS student_answers_updated_at ON student_answers;
+DROP TRIGGER IF EXISTS assignments_updated_at ON assignments;
+DROP TRIGGER IF EXISTS questions_updated_at ON questions;
+DROP TRIGGER IF EXISTS classrooms_updated_at ON classrooms;
+DROP TRIGGER IF EXISTS users_updated_at ON users;
+DROP FUNCTION IF EXISTS update_updated_at();
+
+DROP TABLE IF EXISTS student_answers;
+DROP TABLE IF EXISTS assignment_questions;
+DROP TABLE IF EXISTS assignment_assignees;
+DROP TABLE IF EXISTS assignments;
+DROP TABLE IF EXISTS question_tags;
+DROP TABLE IF EXISTS tags;
+DROP TABLE IF EXISTS questions;
+DROP TABLE IF EXISTS classroom_students;
+DROP TABLE IF EXISTS classrooms;
+DROP TABLE IF EXISTS users;
+
+DROP TYPE IF EXISTS answer_status;
+DROP TYPE IF EXISTS assignment_status;
+DROP TYPE IF EXISTS question_status;
+DROP TYPE IF EXISTS user_role;
--- a/Backend/db/migrations/002_profiles.sql
+++ b/Backend/db/migrations/002_profiles.sql
@@ -0,0 +1,44 @@
+-- +goose Up
+CREATE TABLE profiles (
+    user_id BIGINT PRIMARY KEY REFERENCES users(id) ON DELETE CASCADE,
+    preferred_name VARCHAR(100),
+    profile_icon_url TEXT,
+    headline VARCHAR(255),
+    bio TEXT,
+    timezone VARCHAR(100),
+    locale VARCHAR(20),
+    grade_level VARCHAR(100),
+    learning_goal TEXT,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+INSERT INTO profiles (user_id)
+SELECT id
+FROM users
+ON CONFLICT (user_id) DO NOTHING;
+
+-- +goose StatementBegin
+CREATE OR REPLACE FUNCTION ensure_profile_for_user()
+RETURNS TRIGGER AS $$
+BEGIN
+    INSERT INTO profiles (user_id)
+    VALUES (NEW.id)
+    ON CONFLICT (user_id) DO NOTHING;
+
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+-- +goose StatementEnd
+
+CREATE TRIGGER profiles_updated_at BEFORE UPDATE ON profiles
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER users_ensure_profile_after_insert AFTER INSERT ON users
+    FOR EACH ROW EXECUTE FUNCTION ensure_profile_for_user();
+
+-- +goose Down
+DROP TRIGGER IF EXISTS users_ensure_profile_after_insert ON users;
+DROP TRIGGER IF EXISTS profiles_updated_at ON profiles;
+DROP FUNCTION IF EXISTS ensure_profile_for_user();
+DROP TABLE IF EXISTS profiles;
--- a/Backend/db/migrations/003_messages.sql
+++ b/Backend/db/migrations/003_messages.sql
@@ -0,0 +1,48 @@
+-- +goose Up
+CREATE TABLE message_threads (
+    id BIGSERIAL PRIMARY KEY,
+    created_by_user_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    subject VARCHAR(255) NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    CONSTRAINT message_threads_subject_not_blank CHECK (length(btrim(subject)) > 0)
+);
+
+CREATE TABLE message_thread_participants (
+    thread_id BIGINT NOT NULL REFERENCES message_threads(id) ON DELETE CASCADE,
+    user_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    joined_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    last_read_at TIMESTAMPTZ,
+    archived_at TIMESTAMPTZ,
+    PRIMARY KEY (thread_id, user_id)
+);
+
+CREATE TABLE messages (
+    id BIGSERIAL PRIMARY KEY,
+    thread_id BIGINT NOT NULL REFERENCES message_threads(id) ON DELETE CASCADE,
+    sender_user_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    body TEXT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    CONSTRAINT messages_body_not_blank CHECK (length(btrim(body)) > 0)
+);
+
+CREATE INDEX idx_message_threads_created_by_user_id ON message_threads(created_by_user_id);
+CREATE INDEX idx_message_threads_updated_at ON message_threads(updated_at DESC);
+CREATE INDEX idx_message_thread_participants_user_id ON message_thread_participants(user_id);
+CREATE INDEX idx_messages_thread_id_created_at ON messages(thread_id, created_at DESC);
+CREATE INDEX idx_messages_sender_user_id ON messages(sender_user_id);
+
+CREATE TRIGGER message_threads_updated_at BEFORE UPDATE ON message_threads
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER messages_updated_at BEFORE UPDATE ON messages
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+-- +goose Down
+DROP TRIGGER IF EXISTS messages_updated_at ON messages;
+DROP TRIGGER IF EXISTS message_threads_updated_at ON message_threads;
+
+DROP TABLE IF EXISTS messages;
+DROP TABLE IF EXISTS message_thread_participants;
+DROP TABLE IF EXISTS message_threads;
--- a/Backend/db/migrations/004_student_answer_workspace.sql
+++ b/Backend/db/migrations/004_student_answer_workspace.sql
@@ -0,0 +1,12 @@
+-- +goose Up
+ALTER TABLE student_answers
+    ADD COLUMN solve_mode TEXT NOT NULL DEFAULT 'just_answer',
+    ADD COLUMN working_steps TEXT,
+    ADD CONSTRAINT student_answers_solve_mode_check
+        CHECK (solve_mode IN ('just_answer', 'step_by_step', 'solve_together', 'handwritten'));
+
+-- +goose Down
+ALTER TABLE student_answers
+    DROP CONSTRAINT IF EXISTS student_answers_solve_mode_check,
+    DROP COLUMN IF EXISTS working_steps,
+    DROP COLUMN IF EXISTS solve_mode;
--- a/Backend/db/migrations/005_question_answers_and_correctness.sql
+++ b/Backend/db/migrations/005_question_answers_and_correctness.sql
@@ -0,0 +1,13 @@
+-- +goose Up
+ALTER TABLE questions
+ADD COLUMN correct_answer TEXT;
+
+ALTER TABLE student_answers
+ADD COLUMN is_correct BOOLEAN;
+
+-- +goose Down
+ALTER TABLE student_answers
+DROP COLUMN IF EXISTS is_correct;
+
+ALTER TABLE questions
+DROP COLUMN IF EXISTS correct_answer;
--- a/Backend/db/migrations/006_assignment_level_feedback.sql
+++ b/Backend/db/migrations/006_assignment_level_feedback.sql
@@ -0,0 +1,53 @@
+-- +goose Up
+
+ALTER TABLE assignment_assignees
+    ADD COLUMN ai_feedback TEXT,
+    ADD COLUMN teacher_feedback TEXT;
+
+UPDATE assignment_assignees aa
+SET ai_feedback = aggregated.ai_feedback
+FROM (
+    SELECT
+        sa.assignment_id,
+        sa.student_id,
+        string_agg(
+            format('Question %s: %s', aq.position, btrim(sa.ai_feedback)),
+            E'\n\n'
+            ORDER BY aq.position ASC
+        ) AS ai_feedback
+    FROM student_answers sa
+    JOIN assignment_questions aq
+        ON aq.assignment_id = sa.assignment_id
+       AND aq.question_id = sa.question_id
+    WHERE NULLIF(btrim(sa.ai_feedback), '') IS NOT NULL
+    GROUP BY sa.assignment_id, sa.student_id
+) AS aggregated
+WHERE aa.assignment_id = aggregated.assignment_id
+  AND aa.student_id = aggregated.student_id;
+
+UPDATE assignment_assignees aa
+SET teacher_feedback = aggregated.teacher_feedback
+FROM (
+    SELECT
+        sa.assignment_id,
+        sa.student_id,
+        string_agg(
+            format('Question %s: %s', aq.position, btrim(sa.teacher_feedback)),
+            E'\n\n'
+            ORDER BY aq.position ASC
+        ) AS teacher_feedback
+    FROM student_answers sa
+    JOIN assignment_questions aq
+        ON aq.assignment_id = sa.assignment_id
+       AND aq.question_id = sa.question_id
+    WHERE NULLIF(btrim(sa.teacher_feedback), '') IS NOT NULL
+    GROUP BY sa.assignment_id, sa.student_id
+) AS aggregated
+WHERE aa.assignment_id = aggregated.assignment_id
+  AND aa.student_id = aggregated.student_id;
+
+-- +goose Down
+
+ALTER TABLE assignment_assignees
+    DROP COLUMN IF EXISTS teacher_feedback,
+    DROP COLUMN IF EXISTS ai_feedback;
--- a/Backend/db/migrations/007_review_contract.sql
+++ b/Backend/db/migrations/007_review_contract.sql
@@ -0,0 +1,66 @@
+-- +goose Up
+
+CREATE TYPE assignment_pass_status AS ENUM ('pending', 'pass', 'no_pass');
+
+ALTER TABLE student_answers
+    ADD COLUMN review_needs_attention BOOLEAN NOT NULL DEFAULT FALSE,
+    ADD COLUMN review_issue_reason TEXT,
+    ADD COLUMN review_correctness_score NUMERIC(4,3),
+    ADD COLUMN review_understanding_score NUMERIC(4,3),
+    ADD COLUMN review_question_score NUMERIC(4,3),
+    ADD COLUMN review_confidence NUMERIC(4,3),
+    ADD COLUMN review_tags TEXT[] NOT NULL DEFAULT ARRAY[]::TEXT[],
+    ADD CONSTRAINT student_answers_review_correctness_score_range_check
+        CHECK (review_correctness_score IS NULL OR (review_correctness_score >= 0 AND review_correctness_score <= 1)),
+    ADD CONSTRAINT student_answers_review_understanding_score_range_check
+        CHECK (review_understanding_score IS NULL OR (review_understanding_score >= 0 AND review_understanding_score <= 1)),
+    ADD CONSTRAINT student_answers_review_question_score_range_check
+        CHECK (review_question_score IS NULL OR (review_question_score >= 0 AND review_question_score <= 1)),
+    ADD CONSTRAINT student_answers_review_confidence_range_check
+        CHECK (review_confidence IS NULL OR (review_confidence >= 0 AND review_confidence <= 1));
+
+UPDATE student_answers
+SET review_correctness_score = CASE
+        WHEN is_correct IS TRUE THEN 1.000
+        WHEN is_correct IS FALSE THEN 0.000
+        ELSE NULL
+    END,
+    review_question_score = CASE
+        WHEN is_correct IS TRUE THEN 1.000
+        WHEN is_correct IS FALSE THEN 0.000
+        ELSE NULL
+    END
+WHERE is_correct IS NOT NULL;
+
+ALTER TABLE assignment_assignees
+    ADD COLUMN overall_score NUMERIC(5,2),
+    ADD COLUMN pass_threshold NUMERIC(5,2) NOT NULL DEFAULT 8.00,
+    ADD COLUMN pass_status assignment_pass_status NOT NULL DEFAULT 'pending',
+    ADD CONSTRAINT assignment_assignees_overall_score_range_check
+        CHECK (overall_score IS NULL OR (overall_score >= 0 AND overall_score <= 10)),
+    ADD CONSTRAINT assignment_assignees_pass_threshold_range_check
+        CHECK (pass_threshold >= 0 AND pass_threshold <= 10);
+
+-- +goose Down
+
+ALTER TABLE assignment_assignees
+    DROP CONSTRAINT IF EXISTS assignment_assignees_pass_threshold_range_check,
+    DROP CONSTRAINT IF EXISTS assignment_assignees_overall_score_range_check,
+    DROP COLUMN IF EXISTS pass_status,
+    DROP COLUMN IF EXISTS pass_threshold,
+    DROP COLUMN IF EXISTS overall_score;
+
+ALTER TABLE student_answers
+    DROP CONSTRAINT IF EXISTS student_answers_review_confidence_range_check,
+    DROP CONSTRAINT IF EXISTS student_answers_review_question_score_range_check,
+    DROP CONSTRAINT IF EXISTS student_answers_review_understanding_score_range_check,
+    DROP CONSTRAINT IF EXISTS student_answers_review_correctness_score_range_check,
+    DROP COLUMN IF EXISTS review_tags,
+    DROP COLUMN IF EXISTS review_confidence,
+    DROP COLUMN IF EXISTS review_question_score,
+    DROP COLUMN IF EXISTS review_understanding_score,
+    DROP COLUMN IF EXISTS review_correctness_score,
+    DROP COLUMN IF EXISTS review_issue_reason,
+    DROP COLUMN IF EXISTS review_needs_attention;
+
+DROP TYPE IF EXISTS assignment_pass_status;
--- a/Backend/db/migrations/008_assignment_pass_threshold.sql
+++ b/Backend/db/migrations/008_assignment_pass_threshold.sql
@@ -0,0 +1,22 @@
+-- +goose Up
+
+ALTER TABLE assignments
+    ADD COLUMN pass_threshold NUMERIC(5,2) NOT NULL DEFAULT 8.00,
+    ADD CONSTRAINT assignments_pass_threshold_range_check
+        CHECK (pass_threshold >= 0 AND pass_threshold <= 10);
+
+UPDATE assignments a
+SET pass_threshold = COALESCE(
+    (
+        SELECT MAX(aa.pass_threshold)
+        FROM assignment_assignees aa
+        WHERE aa.assignment_id = a.id
+    ),
+    8.00
+);
+
+-- +goose Down
+
+ALTER TABLE assignments
+    DROP CONSTRAINT IF EXISTS assignments_pass_threshold_range_check,
+    DROP COLUMN IF EXISTS pass_threshold;
--- a/Backend/db/migrations/009_assignment_pass_status_override.sql
+++ b/Backend/db/migrations/009_assignment_pass_status_override.sql
@@ -0,0 +1,9 @@
+-- +goose Up
+
+ALTER TABLE assignment_assignees
+    ADD COLUMN pass_status_override assignment_pass_status;
+
+-- +goose Down
+
+ALTER TABLE assignment_assignees
+    DROP COLUMN IF EXISTS pass_status_override;
--- a/Backend/db/migrations/010_assignment_next_step_outcome.sql
+++ b/Backend/db/migrations/010_assignment_next_step_outcome.sql
@@ -0,0 +1,13 @@
+-- +goose Up
+
+CREATE TYPE assignment_next_step_outcome AS ENUM ('redo', 'accept', 'support');
+
+ALTER TABLE assignment_assignees
+    ADD COLUMN next_step_outcome assignment_next_step_outcome;
+
+-- +goose Down
+
+ALTER TABLE assignment_assignees
+    DROP COLUMN IF EXISTS next_step_outcome;
+
+DROP TYPE IF EXISTS assignment_next_step_outcome;
--- a/Backend/db/migrations/011_backfill_seeded_question_correct_answers.sql
+++ b/Backend/db/migrations/011_backfill_seeded_question_correct_answers.sql
@@ -0,0 +1,80 @@
+-- +goose Up
+
+UPDATE questions AS q
+SET correct_answer = seeded.correct_answer
+FROM (
+    VALUES
+        (1001, '700'),
+        (1002, '25000'),
+        (1003, '7/100'),
+        (1004, '0.37'),
+        (1101, '383'),
+        (1102, '456'),
+        (1103, '2627'),
+        (1104, '196'),
+        (1105, '24'),
+        (1106, '3744'),
+        (1201, '3'),
+        (1202, '-5'),
+        (1203, '-4'),
+        (1301, '11'),
+        (1302, '22'),
+        (1303, '19'),
+        (1401, '1/2'),
+        (1402, '2/3'),
+        (1403, '5/8'),
+        (1411, '5/6'),
+        (1412, '3/4'),
+        (1413, '11/15'),
+        (1414, '11/12'),
+        (1415, '1/2'),
+        (1416, '29/24'),
+        (1421, '1/6'),
+        (1422, '1/2'),
+        (1423, '28'),
+        (1501, '5'),
+        (1502, '7'),
+        (1503, '6'),
+        (1511, '14'),
+        (1512, '31'),
+        (1513, '3n+2'),
+        (1601, '28'),
+        (1602, '40'),
+        (1603, '27'),
+        (1611, '70'),
+        (1612, '75'),
+        (1613, '720'),
+        (1701, '8'),
+        (1702, '5'),
+        (1703, '7'),
+        (1711, '3/8'),
+        (1712, '1/3'),
+        (1801, '15'),
+        (1802, '3/8'),
+        (1803, '51'),
+        (1804, '23'),
+        (1805, '96')
+) AS seeded(id, correct_answer)
+WHERE q.id = seeded.id
+  AND (q.correct_answer IS NULL OR BTRIM(q.correct_answer) = '');
+
+-- +goose Down
+
+UPDATE questions
+SET correct_answer = NULL
+WHERE id IN (
+    1001, 1002, 1003, 1004,
+    1101, 1102, 1103, 1104, 1105, 1106,
+    1201, 1202, 1203,
+    1301, 1302, 1303,
+    1401, 1402, 1403,
+    1411, 1412, 1413, 1414, 1415, 1416,
+    1421, 1422, 1423,
+    1501, 1502, 1503,
+    1511, 1512, 1513,
+    1601, 1602, 1603,
+    1611, 1612, 1613,
+    1701, 1702, 1703,
+    1711, 1712,
+    1801, 1802, 1803, 1804, 1805
+);
--- a/Backend/db/migrations/012_phase_a_topics_difficulty_and_threshold.sql
+++ b/Backend/db/migrations/012_phase_a_topics_difficulty_and_threshold.sql
@@ -0,0 +1,123 @@
+-- +goose Up
+
+CREATE TYPE question_topic AS ENUM (
+    'place_value',
+    'arithmetic',
+    'negative_numbers',
+    'bidmas',
+    'fractions',
+    'algebra',
+    'geometry',
+    'data'
+);
+
+CREATE TYPE question_difficulty AS ENUM ('easy', 'medium', 'hard');
+
+ALTER TABLE questions
+    ADD COLUMN topic question_topic,
+    ADD COLUMN difficulty question_difficulty;
+
+UPDATE questions
+SET topic = CASE BTRIM(COALESCE(subject, ''))
+    WHEN 'Place Value' THEN 'place_value'::question_topic
+    WHEN 'Arithmetic' THEN 'arithmetic'::question_topic
+    WHEN 'Negative Numbers' THEN 'negative_numbers'::question_topic
+    WHEN 'BIDMAS' THEN 'bidmas'::question_topic
+    WHEN 'Fractions' THEN 'fractions'::question_topic
+    WHEN 'Algebra' THEN 'algebra'::question_topic
+    WHEN 'Geometry' THEN 'geometry'::question_topic
+    WHEN 'Data' THEN 'data'::question_topic
+    ELSE NULL
+END
+WHERE topic IS NULL;
+
+UPDATE questions AS q
+SET difficulty = seeded.difficulty::question_difficulty
+FROM (
+    VALUES
+        (1001, 'easy'),
+        (1002, 'medium'),
+        (1003, 'medium'),
+        (1004, 'hard'),
+        (1101, 'easy'),
+        (1102, 'medium'),
+        (1103, 'hard'),
+        (1104, 'medium'),
+        (1105, 'medium'),
+        (1106, 'hard'),
+        (1201, 'easy'),
+        (1202, 'medium'),
+        (1203, 'hard'),
+        (1301, 'easy'),
+        (1302, 'medium'),
+        (1303, 'hard'),
+        (1401, 'easy'),
+        (1402, 'medium'),
+        (1403, 'hard'),
+        (1411, 'easy'),
+        (1412, 'easy'),
+        (1413, 'medium'),
+        (1414, 'medium'),
+        (1415, 'medium'),
+        (1416, 'hard'),
+        (1421, 'easy'),
+        (1422, 'medium'),
+        (1423, 'hard'),
+        (1501, 'easy'),
+        (1502, 'medium'),
+        (1503, 'hard'),
+        (1511, 'easy'),
+        (1512, 'medium'),
+        (1513, 'hard'),
+        (1601, 'easy'),
+        (1602, 'medium'),
+        (1603, 'hard'),
+        (1611, 'easy'),
+        (1612, 'medium'),
+        (1613, 'hard'),
+        (1701, 'easy'),
+        (1702, 'medium'),
+        (1703, 'easy'),
+        (1711, 'medium'),
+        (1712, 'hard'),
+        (1801, 'easy'),
+        (1802, 'medium'),
+        (1803, 'medium'),
+        (1804, 'hard'),
+        (1805, 'hard')
+) AS seeded(id, difficulty)
+WHERE q.id = seeded.id
+  AND q.difficulty IS NULL;
+
+ALTER TABLE assignments
+    ALTER COLUMN pass_threshold SET DEFAULT 6.00;
+
+UPDATE assignments
+SET pass_threshold = 6.00;
+
+ALTER TABLE assignment_assignees
+    ALTER COLUMN pass_threshold SET DEFAULT 6.00;
+
+UPDATE assignment_assignees
+SET pass_threshold = 6.00;
+
+-- +goose Down
+
+UPDATE assignment_assignees
+SET pass_threshold = 8.00;
+
+ALTER TABLE assignment_assignees
+    ALTER COLUMN pass_threshold SET DEFAULT 8.00;
+
+UPDATE assignments
+SET pass_threshold = 8.00;
+
+ALTER TABLE assignments
+    ALTER COLUMN pass_threshold SET DEFAULT 8.00;
+
+ALTER TABLE questions
+    DROP COLUMN IF EXISTS difficulty,
+    DROP COLUMN IF EXISTS topic;
+
+DROP TYPE IF EXISTS question_difficulty;
+DROP TYPE IF EXISTS question_topic;
--- a/Backend/db/migrations/013_redo_assignment_plan.sql
+++ b/Backend/db/migrations/013_redo_assignment_plan.sql
@@ -0,0 +1,11 @@
+-- +goose Up
+
+ALTER TABLE assignment_assignees
+    ADD COLUMN redo_plan TEXT,
+    ADD COLUMN redo_plan_generated_at TIMESTAMPTZ;
+
+-- +goose Down
+
+ALTER TABLE assignment_assignees
+    DROP COLUMN IF EXISTS redo_plan_generated_at,
+    DROP COLUMN IF EXISTS redo_plan;
--- a/Backend/db/migrations/014_assignment_student_questions.sql
+++ b/Backend/db/migrations/014_assignment_student_questions.sql
@@ -0,0 +1,30 @@
+-- +goose Up
+
+CREATE TABLE assignment_student_questions (
+    id BIGSERIAL PRIMARY KEY,
+    assignment_id BIGINT NOT NULL,
+    student_id BIGINT NOT NULL,
+    question_id BIGINT NOT NULL REFERENCES questions(id) ON DELETE CASCADE,
+    position INTEGER NOT NULL CHECK (position > 0),
+    source_bucket TEXT NOT NULL CHECK (btrim(source_bucket) <> ''),
+    source_topic question_topic,
+    source_difficulty question_difficulty,
+    generator_seed BIGINT,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    CONSTRAINT assignment_student_questions_assignment_student_fkey
+        FOREIGN KEY (assignment_id, student_id)
+        REFERENCES assignment_assignees(assignment_id, student_id)
+        ON DELETE CASCADE,
+    CONSTRAINT assignment_student_questions_assignment_student_question_key
+        UNIQUE (assignment_id, student_id, question_id),
+    CONSTRAINT assignment_student_questions_assignment_student_position_key
+        UNIQUE (assignment_id, student_id, position)
+);
+
+CREATE INDEX idx_assignment_student_questions_assignment_student
+    ON assignment_student_questions (assignment_id, student_id);
+
+-- +goose Down
+
+DROP INDEX IF EXISTS idx_assignment_student_questions_assignment_student;
+DROP TABLE IF EXISTS assignment_student_questions;
--- a/Backend/db/queries/assignments.sql
+++ b/Backend/db/queries/assignments.sql
@@ -0,0 +1,391 @@
+-- name: CreateAssignment :one
+INSERT INTO assignments (
+    classroom_id,
+    teacher_id,
+    title,
+    instructions,
+    status,
+    due_at,
+    published_at,
+    pass_threshold
+) VALUES (
+    $1,
+    $2,
+    $3,
+    $4,
+    $5,
+    $6,
+    $7,
+    $8
+)
+RETURNING *;
+
+-- name: AssignStudentToAssignment :exec
+INSERT INTO assignment_assignees (
+  assignment_id,
+  student_id
+) VALUES (
+  $1,
+  $2
+)
+ON CONFLICT (assignment_id, student_id) DO NOTHING;
+
+-- name: DeleteAssignmentAssignee :exec
+DELETE FROM assignment_assignees
+WHERE assignment_id = $1
+  AND student_id = $2;
+
+-- name: GetAssignmentAssignee :one
+SELECT *
+FROM assignment_assignees
+WHERE assignment_id = $1
+  AND student_id = $2;
+
+-- name: UpdateAssignmentAIReview :one
+UPDATE assignment_assignees
+SET ai_feedback = $3,
+    next_step_outcome = NULLIF($4::text, '')::assignment_next_step_outcome
+WHERE assignment_id = $1
+  AND student_id = $2
+RETURNING *;
+
+-- name: UpdateAssignmentRedoPlan :one
+UPDATE assignment_assignees
+SET redo_plan = NULLIF($3::text, ''),
+    redo_plan_generated_at = CASE
+        WHEN NULLIF($3::text, '') IS NULL THEN NULL
+        ELSE NOW()
+    END
+WHERE assignment_id = $1
+  AND student_id = $2
+RETURNING *;
+
+-- name: GetAssignmentRedoPlan :one
+SELECT
+    assignment_id,
+    student_id,
+    redo_plan,
+    redo_plan_generated_at
+FROM assignment_assignees
+WHERE assignment_id = $1
+  AND student_id = $2;
+
+-- name: UpdateAssignmentTeacherFeedback :one
+WITH student_question_set AS (
+    SELECT asq.assignment_id, asq.question_id, asq.position
+    FROM assignment_student_questions asq
+    WHERE asq.assignment_id = $1
+      AND asq.student_id = $2
+), selected_questions AS (
+    SELECT assignment_id, question_id, position
+    FROM student_question_set
+    UNION ALL
+    SELECT aq.assignment_id, aq.question_id, aq.position
+    FROM assignment_questions aq
+    WHERE aq.assignment_id = $1
+      AND NOT EXISTS (SELECT 1 FROM student_question_set)
+), score_summary AS (
+    SELECT CASE
+            WHEN COUNT(sa.id) = 0 THEN NULL
+            ELSE ROUND((AVG(
+                CASE
+                    WHEN sa.is_correct IS NULL THEN COALESCE(sa.review_understanding_score, 0)::NUMERIC
+                    ELSE (
+                        ((CASE WHEN sa.is_correct THEN 1 ELSE 0 END)::NUMERIC) + COALESCE(sa.review_understanding_score, 0)::NUMERIC
+                    ) / 2
+                END
+            ) * 10)::NUMERIC, 2)
+        END AS overall_score
+    FROM selected_questions aq
+    LEFT JOIN student_answers sa
+        ON sa.assignment_id = aq.assignment_id
+       AND sa.question_id = aq.question_id
+       AND sa.student_id = $2
+    WHERE aq.assignment_id = $1
+), updated AS (
+    UPDATE assignment_assignees aa
+    SET teacher_feedback = $3,
+        pass_status_override = NULLIF($4::text, '')::assignment_pass_status,
+        next_step_outcome = NULLIF($5::text, '')::assignment_next_step_outcome,
+        overall_score = (SELECT overall_score FROM score_summary),
+        pass_status = COALESCE(
+            NULLIF($4::text, '')::assignment_pass_status,
+            CASE
+                WHEN (SELECT overall_score FROM score_summary) IS NULL THEN 'pending'::assignment_pass_status
+                WHEN (SELECT overall_score FROM score_summary) >= a.pass_threshold THEN 'pass'::assignment_pass_status
+                ELSE 'no_pass'::assignment_pass_status
+            END
+        )
+    FROM assignments a
+    WHERE aa.assignment_id = $1
+      AND aa.student_id = $2
+      AND a.id = aa.assignment_id
+    RETURNING aa.*
+)
+SELECT *
+FROM updated;
+
+-- name: AddQuestionToAssignment :exec
+INSERT INTO assignment_questions (
+    assignment_id,
+    question_id,
+    position
+) VALUES (
+    $1,
+    $2,
+    $3
+)
+ON CONFLICT (assignment_id, question_id) DO UPDATE
+SET position = EXCLUDED.position;
+
+-- name: DeleteAssignmentStudentQuestions :exec
+DELETE FROM assignment_student_questions
+WHERE assignment_id = $1
+  AND student_id = $2;
+
+-- name: AddAssignmentStudentQuestion :one
+INSERT INTO assignment_student_questions (
+    assignment_id,
+    student_id,
+    question_id,
+    position,
+    source_bucket,
+    source_topic,
+    source_difficulty,
+    generator_seed
+) VALUES (
+    $1,
+    $2,
+    $3,
+    $4,
+    $5,
+    $6,
+    $7,
+    $8
+)
+RETURNING *;
+
+-- name: ListAssignmentStudentQuestions :many
+SELECT *
+FROM assignment_student_questions
+WHERE assignment_id = $1
+  AND student_id = $2
+ORDER BY position ASC, id ASC;
+
+-- name: ListGeneratedQuestionsForAssignmentStudent :many
+SELECT
+    asq.id,
+    asq.assignment_id,
+    asq.student_id,
+    asq.question_id,
+    asq.position,
+    asq.source_bucket,
+    asq.source_topic,
+    asq.source_difficulty,
+    asq.generator_seed,
+    asq.created_at,
+    q.author_teacher_id,
+    q.title,
+    q.prompt,
+    q.subject,
+    q.source,
+    q.status,
+    q.created_at AS question_created_at,
+    q.updated_at AS question_updated_at,
+    q.correct_answer,
+    q.topic,
+    q.difficulty
+FROM assignment_student_questions asq
+JOIN questions q ON q.id = asq.question_id
+WHERE asq.assignment_id = $1
+  AND asq.student_id = $2
+ORDER BY asq.position ASC, asq.id ASC;
+
+-- name: ListAssignmentsByTeacher :many
+SELECT *
+FROM assignments
+WHERE teacher_id = $1
+ORDER BY created_at DESC;
+
+-- name: ListAssignmentsForStudent :many
+SELECT a.*
+FROM assignment_assignees aa
+JOIN assignments a ON a.id = aa.assignment_id
+WHERE aa.student_id = $1
+ORDER BY a.created_at DESC;
+
+-- name: GetAssignmentByID :one
+SELECT *
+FROM assignments
+WHERE id = $1;
+
+-- name: UpdateAssignmentDraft :one
+UPDATE assignments
+SET classroom_id = $2,
+    title = $3,
+    instructions = $4,
+    due_at = $5,
+    pass_threshold = $6,
+    updated_at = NOW()
+WHERE id = $1
+RETURNING *;
+
+-- name: CloseAssignment :one
+UPDATE assignments
+SET status = 'closed'::assignment_status,
+    updated_at = NOW()
+WHERE id = $1
+RETURNING *;
+
+-- name: ListQuestionsForAssignment :many
+SELECT
+    aq.assignment_id,
+    aq.question_id,
+    aq.position,
+    q.author_teacher_id,
+    q.title,
+    q.prompt,
+    q.subject,
+    q.source,
+    q.status,
+    q.created_at,
+    q.updated_at
+FROM assignment_questions aq
+JOIN questions q ON q.id = aq.question_id
+WHERE aq.assignment_id = $1
+ORDER BY aq.position ASC, aq.question_id ASC;
+
+-- name: GetAssignmentReviewSummary :one
+WITH student_question_set AS (
+    SELECT asq.student_id, asq.question_id, asq.position
+    FROM assignment_student_questions asq
+    WHERE asq.assignment_id = $1
+),
+students_with_personalized AS (
+    SELECT DISTINCT student_id
+    FROM student_question_set
+),
+selected_questions AS (
+    SELECT student_id, question_id, position
+    FROM student_question_set
+    UNION ALL
+    SELECT aa.student_id, aq.question_id, aq.position
+    FROM assignment_assignees aa
+    JOIN assignment_questions aq ON aq.assignment_id = aa.assignment_id
+    WHERE aa.assignment_id = $1
+      AND NOT EXISTS (
+            SELECT 1
+            FROM students_with_personalized swp
+            WHERE swp.student_id = aa.student_id
+        )
+),
+student_states AS (
+    SELECT
+        aa.student_id,
+        COUNT(sq.question_id)::BIGINT AS total_questions,
+        CASE
+            WHEN COUNT(sa.id) = 0 THEN 'not_started'::answer_status
+            WHEN COUNT(sq.question_id) > 0
+                AND COUNT(sa.id) FILTER (WHERE sa.status = 'reviewed') = COUNT(sq.question_id)
+                THEN 'reviewed'::answer_status
+            WHEN COUNT(sa.id) FILTER (WHERE sa.status = 'submitted') > 0 THEN 'submitted'::answer_status
+            WHEN COUNT(sa.id) FILTER (WHERE sa.status = 'in_progress') > 0 THEN 'in_progress'::answer_status
+            WHEN COUNT(sa.id) FILTER (WHERE sa.status = 'reviewed') > 0 THEN 'in_progress'::answer_status
+            ELSE 'not_started'::answer_status
+        END AS review_status
+    FROM assignment_assignees aa
+    LEFT JOIN selected_questions sq
+        ON sq.student_id = aa.student_id
+    LEFT JOIN student_answers sa
+        ON sa.assignment_id = aa.assignment_id
+       AND sa.question_id = sq.question_id
+       AND sa.student_id = aa.student_id
+    WHERE aa.assignment_id = $1
+    GROUP BY aa.student_id
+)
+SELECT
+    $1::BIGINT AS assignment_id,
+    COALESCE(MAX(student_states.total_questions), 0)::BIGINT AS total_questions,
+    COUNT(*)::BIGINT AS total_assigned,
+    COUNT(*) FILTER (WHERE review_status = 'not_started')::BIGINT AS not_started,
+    COUNT(*) FILTER (WHERE review_status = 'in_progress')::BIGINT AS in_progress,
+    COUNT(*) FILTER (WHERE review_status = 'submitted')::BIGINT AS submitted,
+    COUNT(*) FILTER (WHERE review_status = 'reviewed')::BIGINT AS reviewed
+FROM student_states;
+
+-- name: ListAssignmentReviewQueue :many
+WITH student_question_set AS (
+    SELECT asq.student_id, asq.question_id, asq.position
+    FROM assignment_student_questions asq
+    WHERE asq.assignment_id = $1
+),
+students_with_personalized AS (
+    SELECT DISTINCT student_id
+    FROM student_question_set
+),
+selected_questions AS (
+    SELECT student_id, question_id, position
+    FROM student_question_set
+    UNION ALL
+    SELECT aa.student_id, aq.question_id, aq.position
+    FROM assignment_assignees aa
+    JOIN assignment_questions aq ON aq.assignment_id = aa.assignment_id
+    WHERE aa.assignment_id = $1
+      AND NOT EXISTS (
+            SELECT 1
+            FROM students_with_personalized swp
+            WHERE swp.student_id = aa.student_id
+        )
+),
+student_states AS (
+    SELECT
+        aa.assignment_id,
+        aa.student_id,
+        aa.next_step_outcome,
+        u.full_name AS student_name,
+        u.email AS student_email,
+        COUNT(sq.question_id)::BIGINT AS total_questions,
+        COUNT(sa.id)::BIGINT AS answered_questions,
+        COUNT(sa.id) FILTER (WHERE sa.status = 'reviewed')::BIGINT AS reviewed_questions,
+        COUNT(sa.id) FILTER (WHERE sa.status = 'submitted')::BIGINT AS submitted_questions,
+        COUNT(sa.id) FILTER (WHERE sa.status = 'in_progress')::BIGINT AS in_progress_questions,
+        MAX(sa.submitted_at)::timestamptz AS latest_submitted_at,
+        MAX(sa.reviewed_at)::timestamptz AS latest_reviewed_at,
+        CASE
+            WHEN COUNT(sa.id) = 0 THEN 'not_started'::answer_status
+            WHEN COUNT(sq.question_id) > 0
+                AND COUNT(sa.id) FILTER (WHERE sa.status = 'reviewed') = COUNT(sq.question_id)
+                THEN 'reviewed'::answer_status
+            WHEN COUNT(sa.id) FILTER (WHERE sa.status = 'submitted') > 0 THEN 'submitted'::answer_status
+            WHEN COUNT(sa.id) FILTER (WHERE sa.status = 'in_progress') > 0 THEN 'in_progress'::answer_status
+            WHEN COUNT(sa.id) FILTER (WHERE sa.status = 'reviewed') > 0 THEN 'in_progress'::answer_status
+            ELSE 'not_started'::answer_status
+        END AS review_status
+    FROM assignment_assignees aa
+    JOIN users u ON u.id = aa.student_id
+    LEFT JOIN selected_questions sq
+        ON sq.student_id = aa.student_id
+    LEFT JOIN student_answers sa
+        ON sa.assignment_id = aa.assignment_id
+       AND sa.question_id = sq.question_id
+       AND sa.student_id = aa.student_id
+    WHERE aa.assignment_id = $1
+    GROUP BY aa.assignment_id, aa.student_id, aa.next_step_outcome, u.full_name, u.email
+)
+SELECT
+    student_states.assignment_id,
+    student_states.student_id,
+    student_states.next_step_outcome,
+    student_states.student_name,
+    student_states.student_email,
+    student_states.total_questions,
+    student_states.answered_questions,
+    student_states.reviewed_questions,
+    student_states.submitted_questions,
+    student_states.in_progress_questions,
+    student_states.review_status,
+    student_states.latest_submitted_at,
+    student_states.latest_reviewed_at
+FROM student_states
+WHERE ($2::text = '' OR review_status::text = $2::text)
+ORDER BY student_states.student_name ASC, student_states.student_id ASC;
--- a/Backend/db/queries/classrooms.sql
+++ b/Backend/db/queries/classrooms.sql
@@ -0,0 +1,36 @@
+-- name: CreateClassroom :one
+INSERT INTO classrooms (
+    teacher_id,
+    name,
+    code,
+    description
+) VALUES (
+    $1,
+    $2,
+    $3,
+    $4
+)
+RETURNING *;
+
+-- name: ListClassroomsByTeacher :many
+SELECT *
+FROM classrooms
+WHERE teacher_id = $1
+ORDER BY created_at DESC;
+
+-- name: AddStudentToClassroom :exec
+INSERT INTO classroom_students (
+    classroom_id,
+    student_id
+) VALUES (
+    $1,
+    $2
+)
+ON CONFLICT (classroom_id, student_id) DO NOTHING;
+
+-- name: ListStudentsForClassroom :many
+SELECT u.*
+FROM classroom_students cs
+JOIN users u ON u.id = cs.student_id
+WHERE cs.classroom_id = $1
+ORDER BY u.full_name ASC;
--- a/Backend/db/queries/messages.sql
+++ b/Backend/db/queries/messages.sql
@@ -0,0 +1,266 @@
+-- name: ListMessageRecipientsForUser :many
+SELECT
+    u.id AS user_id,
+    u.email AS user_email,
+    u.role AS user_role,
+    u.full_name AS user_full_name,
+    p.preferred_name,
+    p.profile_icon_url,
+    p.headline
+FROM users u
+LEFT JOIN profiles p ON p.user_id = u.id
+WHERE u.id <> $1
+  AND u.is_active = TRUE
+  AND (
+    EXISTS (
+        SELECT 1
+        FROM classrooms c
+        JOIN classroom_students cs ON cs.classroom_id = c.id
+        WHERE c.teacher_id = u.id
+          AND cs.student_id = $1
+    )
+    OR EXISTS (
+        SELECT 1
+        FROM classrooms c
+        JOIN classroom_students cs ON cs.classroom_id = c.id
+        WHERE c.teacher_id = $1
+          AND cs.student_id = u.id
+    )
+  )
+ORDER BY COALESCE(NULLIF(p.preferred_name, ''), u.full_name) ASC, u.id ASC;
+
+-- name: GetMessageRecipientByIDForUser :one
+SELECT
+    u.id AS user_id,
+    u.email AS user_email,
+    u.role AS user_role,
+    u.full_name AS user_full_name,
+    p.preferred_name,
+    p.profile_icon_url,
+    p.headline
+FROM users u
+LEFT JOIN profiles p ON p.user_id = u.id
+WHERE u.id = $2
+  AND u.id <> $1
+  AND u.is_active = TRUE
+  AND (
+    EXISTS (
+        SELECT 1
+        FROM classrooms c
+        JOIN classroom_students cs ON cs.classroom_id = c.id
+        WHERE c.teacher_id = u.id
+          AND cs.student_id = $1
+    )
+    OR EXISTS (
+        SELECT 1
+        FROM classrooms c
+        JOIN classroom_students cs ON cs.classroom_id = c.id
+        WHERE c.teacher_id = $1
+          AND cs.student_id = u.id
+    )
+  )
+LIMIT 1;
+
+-- name: ListMessageThreadsForUser :many
+SELECT
+    t.id AS thread_id,
+    t.subject,
+    t.created_by_user_id,
+    t.created_at AS thread_created_at,
+    t.updated_at AS thread_updated_at,
+    COALESCE(last_message.id, 0)::bigint AS last_message_id,
+    COALESCE(last_message.body, '') AS last_message_body,
+    last_message.created_at AS last_message_created_at,
+    COALESCE(last_message.sender_user_id, 0)::bigint AS last_message_sender_user_id,
+    sender.full_name AS last_message_sender_full_name,
+    sender_profile.preferred_name AS last_message_sender_preferred_name,
+    sender_profile.profile_icon_url AS last_message_sender_profile_icon_url,
+    COALESCE((
+        SELECT COUNT(*)::bigint
+        FROM messages unread
+        WHERE unread.thread_id = t.id
+          AND unread.sender_user_id <> $1
+          AND (participant.last_read_at IS NULL OR unread.created_at > participant.last_read_at)
+    ), 0)::bigint AS unread_count
+FROM message_thread_participants participant
+JOIN message_threads t ON t.id = participant.thread_id
+LEFT JOIN LATERAL (
+    SELECT m.id, m.body, m.created_at, m.sender_user_id
+    FROM messages m
+    WHERE m.thread_id = t.id
+    ORDER BY m.created_at DESC, m.id DESC
+    LIMIT 1
+) AS last_message ON TRUE
+LEFT JOIN users sender ON sender.id = last_message.sender_user_id
+LEFT JOIN profiles sender_profile ON sender_profile.user_id = sender.id
+WHERE participant.user_id = $1
+  AND participant.archived_at IS NULL
+ORDER BY COALESCE(last_message.created_at, t.updated_at) DESC, t.id DESC;
+
+-- name: ListMessageThreadParticipantsForUser :many
+SELECT
+    mtp.thread_id,
+    u.id AS user_id,
+    u.email AS user_email,
+    u.role AS user_role,
+    u.full_name AS user_full_name,
+    p.preferred_name,
+    p.profile_icon_url,
+    p.headline,
+    mtp.joined_at,
+    mtp.last_read_at,
+    mtp.archived_at
+FROM message_thread_participants mtp
+JOIN users u ON u.id = mtp.user_id
+LEFT JOIN profiles p ON p.user_id = u.id
+WHERE mtp.thread_id IN (
+    SELECT participant.thread_id
+    FROM message_thread_participants participant
+    WHERE participant.user_id = $1
+      AND participant.archived_at IS NULL
+)
+ORDER BY mtp.thread_id ASC, COALESCE(NULLIF(p.preferred_name, ''), u.full_name) ASC, u.id ASC;
+
+-- name: GetMessageThreadForUser :one
+SELECT
+    t.id,
+    t.subject,
+    t.created_by_user_id,
+    t.created_at,
+    t.updated_at,
+    participant.last_read_at,
+    COALESCE((
+        SELECT COUNT(*)::bigint
+        FROM messages unread
+        WHERE unread.thread_id = t.id
+          AND unread.sender_user_id <> $2
+          AND (participant.last_read_at IS NULL OR unread.created_at > participant.last_read_at)
+    ), 0)::bigint AS unread_count
+FROM message_threads t
+JOIN message_thread_participants participant ON participant.thread_id = t.id
+WHERE t.id = $1
+  AND participant.user_id = $2
+  AND participant.archived_at IS NULL;
+
+-- name: ListMessagesForThreadForUser :many
+SELECT
+    m.id,
+    m.thread_id,
+    m.sender_user_id,
+    m.body,
+    m.created_at,
+    m.updated_at,
+    sender.email AS sender_email,
+    sender.role AS sender_role,
+    sender.full_name AS sender_full_name,
+    sender_profile.preferred_name AS sender_preferred_name,
+    sender_profile.profile_icon_url AS sender_profile_icon_url,
+    sender_profile.headline AS sender_headline
+FROM messages m
+JOIN message_thread_participants participant ON participant.thread_id = m.thread_id
+JOIN users sender ON sender.id = m.sender_user_id
+LEFT JOIN profiles sender_profile ON sender_profile.user_id = sender.id
+WHERE m.thread_id = $1
+  AND participant.user_id = $2
+  AND participant.archived_at IS NULL
+ORDER BY m.created_at ASC, m.id ASC;
+
+-- name: ListParticipantsForThreadForUser :many
+SELECT
+    mtp.thread_id,
+    u.id AS user_id,
+    u.email AS user_email,
+    u.role AS user_role,
+    u.full_name AS user_full_name,
+    p.preferred_name,
+    p.profile_icon_url,
+    p.headline,
+    mtp.joined_at,
+    mtp.last_read_at,
+    mtp.archived_at
+FROM message_thread_participants mtp
+JOIN users u ON u.id = mtp.user_id
+LEFT JOIN profiles p ON p.user_id = u.id
+WHERE mtp.thread_id = $1
+  AND EXISTS (
+    SELECT 1
+    FROM message_thread_participants participant
+    WHERE participant.thread_id = mtp.thread_id
+      AND participant.user_id = $2
+      AND participant.archived_at IS NULL
+  )
+ORDER BY COALESCE(NULLIF(p.preferred_name, ''), u.full_name) ASC, u.id ASC;
+
+-- name: CreateMessageThread :one
+INSERT INTO message_threads (
+    created_by_user_id,
+    subject
+) VALUES (
+    $1,
+    $2
+)
+RETURNING *;
+
+-- name: AddMessageThreadParticipant :exec
+INSERT INTO message_thread_participants (
+    thread_id,
+    user_id,
+    last_read_at
+) VALUES (
+    $1,
+    $2,
+    $3
+)
+ON CONFLICT (thread_id, user_id) DO NOTHING;
+
+-- name: CreateThreadMessage :one
+INSERT INTO messages (
+    thread_id,
+    sender_user_id,
+    body
+) VALUES (
+    $1,
+    $2,
+    $3
+)
+RETURNING *;
+
+-- name: TouchMessageThread :exec
+UPDATE message_threads
+SET updated_at = NOW()
+WHERE id = $1;
+
+-- name: UpdateMessageThreadSubject :one
+UPDATE message_threads
+SET subject = sqlc.arg(subject),
+    updated_at = NOW()
+WHERE id = sqlc.arg(thread_id)
+RETURNING *;
+
+-- name: UpdateThreadMessageBody :one
+UPDATE messages
+SET body = sqlc.arg(body),
+    updated_at = NOW()
+WHERE id = sqlc.arg(message_id)
+  AND thread_id = sqlc.arg(thread_id)
+  AND sender_user_id = sqlc.arg(user_id)
+RETURNING *;
+
+-- name: DeleteThreadMessage :one
+DELETE FROM messages
+WHERE id = sqlc.arg(message_id)
+  AND thread_id = sqlc.arg(thread_id)
+  AND sender_user_id = sqlc.arg(user_id)
+RETURNING *;
+
+-- name: DeleteMessageThread :one
+DELETE FROM message_threads
+WHERE id = sqlc.arg(thread_id)
+RETURNING *;
+
+-- name: MarkMessageThreadRead :one
+UPDATE message_thread_participants
+SET last_read_at = COALESCE((SELECT MAX(m.created_at) FROM messages m WHERE m.thread_id = $1), NOW())
+WHERE message_thread_participants.thread_id = $1
+  AND message_thread_participants.user_id = $2
+RETURNING *;
--- a/Backend/db/queries/questions.sql
+++ b/Backend/db/queries/questions.sql
@@ -0,0 +1,55 @@
+-- name: CreateQuestion :one
+INSERT INTO questions (
+    author_teacher_id,
+    title,
+    prompt,
+    topic,
+    subject,
+    difficulty,
+    source,
+    status,
+    correct_answer
+) VALUES (
+    $1,
+    $2,
+    $3,
+    $4,
+    $5,
+    $6,
+    $7,
+    $8,
+    $9
+)
+RETURNING *;
+
+-- name: ListQuestionsByTeacher :many
+SELECT *
+FROM questions
+WHERE author_teacher_id = $1
+ORDER BY created_at DESC;
+
+-- name: GetQuestionByID :one
+SELECT *
+FROM questions
+WHERE id = $1;
+
+-- name: CreateTag :one
+INSERT INTO tags (name)
+VALUES ($1)
+ON CONFLICT (name) DO UPDATE SET name = EXCLUDED.name
+RETURNING *;
+
+-- name: AttachTagToQuestion :exec
+INSERT INTO question_tags (
+    question_id,
+    tag_id
+) VALUES (
+    $1,
+    $2
+)
+ON CONFLICT (question_id, tag_id) DO NOTHING;
+
+-- name: ListTags :many
+SELECT *
+FROM tags
+ORDER BY name ASC;
--- a/Backend/db/queries/student_answers.sql
+++ b/Backend/db/queries/student_answers.sql
@@ -0,0 +1,228 @@
+-- name: UpsertStudentAnswer :one
+INSERT INTO student_answers (
+    assignment_id,
+    question_id,
+    student_id,
+    answer_text,
+    solve_mode,
+    working_steps,
+    ai_feedback,
+    teacher_feedback,
+    status,
+    submitted_at,
+    reviewed_at,
+    is_correct
+) VALUES (
+    $1,
+    $2,
+    $3,
+    $4,
+    $5,
+    $6,
+    $7,
+    $8,
+    $9,
+    $10,
+    $11,
+    $12
+)
+ON CONFLICT (assignment_id, question_id, student_id) DO UPDATE
+SET
+    answer_text = EXCLUDED.answer_text,
+    solve_mode = EXCLUDED.solve_mode,
+    working_steps = EXCLUDED.working_steps,
+    ai_feedback = EXCLUDED.ai_feedback,
+    teacher_feedback = EXCLUDED.teacher_feedback,
+    status = EXCLUDED.status,
+    submitted_at = EXCLUDED.submitted_at,
+    reviewed_at = EXCLUDED.reviewed_at,
+    is_correct = EXCLUDED.is_correct,
+    updated_at = NOW()
+RETURNING *;
+
+-- name: UpdateAnswerAIReview :one
+UPDATE student_answers
+SET
+    ai_feedback = $2,
+    review_needs_attention = $3,
+    review_issue_reason = $4,
+    review_correctness_score = $5,
+    review_understanding_score = $6,
+    review_question_score = $7,
+    review_confidence = $8,
+    updated_at = NOW()
+WHERE id = $1
+RETURNING *;
+
+-- name: ListAnswersForAssignment :many
+SELECT *
+FROM student_answers
+WHERE assignment_id = $1
+ORDER BY created_at ASC;
+
+-- name: ListAnswersForStudent :many
+SELECT *
+FROM student_answers
+WHERE student_id = $1
+ORDER BY created_at DESC;
+
+-- name: ListQuestionDetailsForAssignmentStudent :many
+WITH student_question_set AS (
+    SELECT
+        asq.assignment_id,
+        asq.question_id,
+        asq.position
+    FROM assignment_student_questions asq
+    WHERE asq.assignment_id = $1
+      AND asq.student_id = $2
+),
+selected_questions AS (
+    SELECT
+        sq.assignment_id,
+        sq.question_id,
+        sq.position
+    FROM student_question_set sq
+    UNION ALL
+    SELECT
+        aq.assignment_id,
+        aq.question_id,
+        aq.position
+    FROM assignment_questions aq
+    WHERE aq.assignment_id = $1
+      AND NOT EXISTS (SELECT 1 FROM student_question_set)
+)
+SELECT
+    aq.assignment_id,
+    aq.question_id,
+    aq.position,
+    q.title,
+    q.prompt,
+    q.subject,
+    q.source,
+    COALESCE(
+        ARRAY(
+            SELECT t.name
+            FROM question_tags qt
+            JOIN tags t ON t.id = qt.tag_id
+            WHERE qt.question_id = aq.question_id
+            ORDER BY t.name ASC
+        ),
+        ARRAY[]::TEXT[]
+    )::TEXT[] AS question_tags,
+    q.status AS question_status,
+    q.correct_answer,
+    aa.ai_feedback AS assignment_ai_feedback,
+    aa.teacher_feedback AS assignment_teacher_feedback,
+    review_summary.overall_score,
+    a.pass_threshold,
+    aa.next_step_outcome,
+    aa.pass_status_override,
+    COALESCE(
+        aa.pass_status_override,
+        CASE
+            WHEN review_summary.overall_score IS NULL THEN 'pending'::assignment_pass_status
+            WHEN review_summary.overall_score >= a.pass_threshold THEN 'pass'::assignment_pass_status
+            ELSE 'no_pass'::assignment_pass_status
+        END
+    ) AS pass_status,
+    sa.id AS answer_id,
+    sa.student_id,
+    sa.answer_text,
+    sa.solve_mode,
+    sa.working_steps,
+    sa.is_correct,
+    sa.ai_feedback,
+    sa.teacher_feedback,
+    sa.status AS answer_status,
+    sa.review_needs_attention,
+    sa.review_issue_reason,
+    sa.review_correctness_score,
+    sa.review_understanding_score,
+    sa.review_question_score,
+    sa.review_confidence,
+    sa.review_tags,
+    sa.submitted_at,
+    sa.reviewed_at,
+    sa.created_at AS answer_created_at,
+    sa.updated_at AS answer_updated_at
+ FROM selected_questions aq
+ JOIN assignments a ON a.id = aq.assignment_id
+ JOIN questions q ON q.id = aq.question_id
+ LEFT JOIN assignment_assignees aa
+    ON aa.assignment_id = aq.assignment_id
+    AND aa.student_id = $2
+ LEFT JOIN LATERAL (
+     SELECT CASE
+             WHEN COUNT(sa2.id) = 0 THEN NULL::NUMERIC(5,2)
+             ELSE ROUND((AVG(
+                CASE
+                    WHEN sa2.is_correct IS NULL THEN COALESCE(sa2.review_understanding_score, 0)::NUMERIC
+                    ELSE (
+                        ((CASE WHEN sa2.is_correct THEN 1 ELSE 0 END)::NUMERIC) + COALESCE(sa2.review_understanding_score, 0)::NUMERIC
+                    ) / 2
+                END
+             ) * 10)::NUMERIC, 2)::NUMERIC(5,2)
+         END AS overall_score
+    FROM selected_questions aq2
+    LEFT JOIN student_answers sa2
+        ON sa2.assignment_id = aq2.assignment_id
+       AND sa2.question_id = aq2.question_id
+       AND sa2.student_id = $2
+    WHERE aq2.assignment_id = aq.assignment_id
+) review_summary ON TRUE
+LEFT JOIN student_answers sa
+    ON sa.assignment_id = aq.assignment_id
+   AND sa.question_id = aq.question_id
+   AND sa.student_id = $2
+WHERE aq.assignment_id = $1
+ORDER BY aq.position ASC, aq.question_id ASC;
+
+-- name: UpdateAnswerReview :one
+UPDATE student_answers
+SET
+    status = $2,
+    review_needs_attention = $3,
+    review_issue_reason = $4,
+    review_correctness_score = $5,
+    review_understanding_score = $6,
+    review_question_score = $7,
+    review_confidence = $8,
+    review_tags = $9,
+    reviewed_at = CASE
+        WHEN $2::answer_status = 'reviewed' THEN NOW()
+        ELSE NULL
+    END,
+    updated_at = NOW()
+WHERE id = $1
+RETURNING *;
+
+-- name: ListStudentPlanningPerformance :many
+SELECT
+    sa.assignment_id,
+    sa.question_id,
+    q.topic,
+    q.subject,
+    q.difficulty,
+    COALESCE(
+        ARRAY(
+            SELECT t.name
+            FROM question_tags qt
+            JOIN tags t ON t.id = qt.tag_id
+            WHERE qt.question_id = sa.question_id
+            ORDER BY t.name ASC
+        ),
+        ARRAY[]::TEXT[]
+    )::TEXT[] AS question_tags,
+    sa.is_correct,
+    sa.review_understanding_score,
+    sa.review_needs_attention,
+    sa.review_issue_reason,
+    sa.status,
+    sa.submitted_at,
+    sa.reviewed_at,
+    sa.updated_at
+FROM student_answers sa
+JOIN questions q ON q.id = sa.question_id
+WHERE sa.student_id = $1
+  AND sa.status IN ('submitted'::answer_status, 'reviewed'::answer_status)
+ORDER BY COALESCE(sa.reviewed_at, sa.submitted_at, sa.updated_at) DESC, sa.id DESC;
--- a/Backend/db/queries/users.sql
+++ b/Backend/db/queries/users.sql
@@ -0,0 +1,178 @@
+-- name: CreateUser :one
+INSERT INTO users (
+    email,
+    password_hash,
+    role,
+    full_name
+) VALUES (
+    $1,
+    $2,
+    $3,
+    $4
+)
+RETURNING *;
+
+-- name: GetUserByID :one
+SELECT *
+FROM users
+WHERE id = $1;
+
+-- name: GetAuthUserByID :one
+SELECT
+    u.id AS user_id,
+    u.email AS user_email,
+    u.role AS user_role,
+    u.full_name AS user_full_name,
+    u.is_active AS user_is_active,
+    u.created_at AS user_created_at,
+    u.updated_at AS user_updated_at,
+    p.user_id AS profile_user_id,
+    p.preferred_name,
+    p.profile_icon_url,
+    p.headline,
+    p.bio,
+    p.timezone,
+    p.locale,
+    p.grade_level,
+    p.learning_goal,
+    p.created_at AS profile_created_at,
+    p.updated_at AS profile_updated_at
+FROM users u
+LEFT JOIN profiles p ON p.user_id = u.id
+WHERE u.id = $1;
+
+-- name: GetUserByEmail :one
+SELECT *
+FROM users
+WHERE email = $1;
+
+-- name: GetAuthUserByEmail :one
+SELECT
+    u.id AS user_id,
+    u.email AS user_email,
+    u.role AS user_role,
+    u.full_name AS user_full_name,
+    u.is_active AS user_is_active,
+    u.password_hash AS user_password_hash,
+    u.created_at AS user_created_at,
+    u.updated_at AS user_updated_at,
+    p.user_id AS profile_user_id,
+    p.preferred_name,
+    p.profile_icon_url,
+    p.headline,
+    p.bio,
+    p.timezone,
+    p.locale,
+    p.grade_level,
+    p.learning_goal,
+    p.created_at AS profile_created_at,
+    p.updated_at AS profile_updated_at
+FROM users u
+LEFT JOIN profiles p ON p.user_id = u.id
+WHERE u.email = $1;
+
+-- name: ListUsersByRole :many
+SELECT *
+FROM users
+WHERE role = $1
+ORDER BY full_name ASC;
+
+-- name: ListUsersWithProfileByRole :many
+SELECT
+    u.id AS user_id,
+    u.email AS user_email,
+    u.role AS user_role,
+    u.full_name AS user_full_name,
+    u.is_active AS user_is_active,
+    u.created_at AS user_created_at,
+    u.updated_at AS user_updated_at,
+    p.user_id AS profile_user_id,
+    p.preferred_name,
+    p.profile_icon_url,
+    p.headline,
+    p.bio,
+    p.timezone,
+    p.locale,
+    p.grade_level,
+    p.learning_goal,
+    p.created_at AS profile_created_at,
+    p.updated_at AS profile_updated_at
+FROM users u
+LEFT JOIN profiles p ON p.user_id = u.id
+WHERE u.role = $1
+ORDER BY u.full_name ASC;
+
+-- name: GetUserWithProfileByID :one
+SELECT
+    u.id AS user_id,
+    u.email AS user_email,
+    u.role AS user_role,
+    u.full_name AS user_full_name,
+    u.is_active AS user_is_active,
+    u.created_at AS user_created_at,
+    u.updated_at AS user_updated_at,
+    p.user_id AS profile_user_id,
+    p.preferred_name,
+    p.profile_icon_url,
+    p.headline,
+    p.bio,
+    p.timezone,
+    p.locale,
+    p.grade_level,
+    p.learning_goal,
+    p.created_at AS profile_created_at,
+    p.updated_at AS profile_updated_at
+FROM users u
+LEFT JOIN profiles p ON p.user_id = u.id
+WHERE u.id = $1;
+
+-- name: UpdateUserActiveStatus :one
+UPDATE users
+SET
+    is_active = $2,
+    updated_at = NOW()
+WHERE id = $1
+RETURNING *;
+
+-- name: UpdateUserFullName :one
+UPDATE users
+SET
+    full_name = $2,
+    updated_at = NOW()
+WHERE id = $1
+RETURNING *;
+
+-- name: UpsertUserProfile :one
+INSERT INTO profiles (
+    user_id,
+    preferred_name,
+    profile_icon_url,
+    headline,
+    bio,
+    timezone,
+    locale,
+    grade_level,
+    learning_goal
+) VALUES (
+    $1,
+    $2,
+    $3,
+    $4,
+    $5,
+    $6,
+    $7,
+    $8,
+    $9
+)
+ON CONFLICT (user_id) DO UPDATE
+SET
+    preferred_name = EXCLUDED.preferred_name,
+    profile_icon_url = EXCLUDED.profile_icon_url,
+    headline = EXCLUDED.headline,
+    bio = EXCLUDED.bio,
+    timezone = EXCLUDED.timezone,
+    locale = EXCLUDED.locale,
+    grade_level = EXCLUDED.grade_level,
+    learning_goal = EXCLUDED.learning_goal,
+    updated_at = NOW()
+RETURNING *;
--- a/Backend/db/sqlc.yaml
+++ b/Backend/db/sqlc.yaml
@@ -0,0 +1,12 @@
+version: "2"
+sql:
+  - engine: "postgresql"
+    queries: "queries/"
+    schema: "migrations/"
+    gen:
+      go:
+        package: "sqlc"
+        out: "../internal/sqlc"
+        sql_package: "pgx/v5"
+        emit_json_tags: true
+        emit_empty_slices: true