#!/bin/bash

# Path: Scripts/go.sh

set -e

BLUE='\033[1;34m'
YELLOW='\033[1;33m'
GREEN='\033[1;32m'
RED='\033[1;31m'
NC='\033[0m'

export GVM_ROOT="$HOME/.programming/go"
BOOTSTRAP_GO="$GVM_ROOT/bootstrap"
GO_BOOTSTRAP_VERSION="1.20.5"

OS_NAME="$(uname -s)"
ARCH="$(uname -m)"

case "$ARCH" in
    x86_64)
        GO_BOOTSTRAP_ARCH="amd64"
        ;;
    aarch64|arm64)
        GO_BOOTSTRAP_ARCH="arm64"
        ;;
    *)
        echo -e "${RED}    ERROR:${NC} Unsupported architecture for Go bootstrap: $ARCH"
        exit 1
        ;;
esac

case "$OS_NAME" in
    Linux)
        GO_BOOTSTRAP_OS="linux"
        ;;
    Darwin)
        GO_BOOTSTRAP_OS="darwin"
        ;;
    *)
        echo -e "${RED}    ERROR:${NC} Unsupported operating system for Go bootstrap: $OS_NAME"
        exit 1
        ;;
esac

GO_BOOTSTRAP_FILENAME="go${GO_BOOTSTRAP_VERSION}.${GO_BOOTSTRAP_OS}-${GO_BOOTSTRAP_ARCH}.tar.gz"
GO_BOOTSTRAP_URL="https://go.dev/dl/${GO_BOOTSTRAP_FILENAME}"
GO_RELEASE_METADATA_URL="https://go.dev/dl/?mode=json&include=all"

sha256_file() {
    local file_path="$1"

    if command -v sha256sum >/dev/null 2>&1; then
        sha256sum "$file_path" | awk '{print $1}'
    elif command -v shasum >/dev/null 2>&1; then
        shasum -a 256 "$file_path" | awk '{print $1}'
    else
        echo -e "${RED}    ERROR:${NC} No SHA256 tool found (need sha256sum or shasum)."
        exit 1
    fi
}

get_go_release_sha256() {
    python3 - "$GO_RELEASE_METADATA_URL" "$GO_BOOTSTRAP_FILENAME" <<'PY'
import json
import sys
import urllib.request

metadata_url = sys.argv[1]
target_filename = sys.argv[2]

with urllib.request.urlopen(metadata_url, timeout=30) as response:
    releases = json.load(response)

for release in releases:
    for file_info in release.get("files", []):
        if file_info.get("filename") == target_filename:
            print(file_info.get("sha256", ""))
            raise SystemExit(0)

raise SystemExit(1)
PY
}

download_and_verify_go_bootstrap() {
    local destination_path="$1"
    local expected_sha256=""
    local actual_sha256=""
    local temp_tarball=""

    temp_tarball="$(mktemp "${TMPDIR:-/tmp}/go-bootstrap.XXXXXX")"

    cleanup_go_bootstrap_download() {
        rm -f "$temp_tarball"
    }

    trap cleanup_go_bootstrap_download RETURN

    echo -e "${BLUE}    LOG:${YELLOW} Downloading pinned Bootstrap Go ${GO_BOOTSTRAP_VERSION}...${NC}"
    curl -fsSL "$GO_BOOTSTRAP_URL" -o "$temp_tarball"

    expected_sha256="$(get_go_release_sha256)"
    if [ -z "$expected_sha256" ]; then
        echo -e "${RED}    ERROR:${NC} Could not find official SHA256 for ${GO_BOOTSTRAP_FILENAME}."
        exit 1
    fi

    actual_sha256="$(sha256_file "$temp_tarball")"
    if [ "$actual_sha256" != "$expected_sha256" ]; then
        echo -e "${RED}    ERROR:${NC} Bootstrap Go checksum mismatch for ${GO_BOOTSTRAP_FILENAME}."
        echo -e "${RED}    ERROR:${NC} Expected: ${expected_sha256}"
        echo -e "${RED}    ERROR:${NC} Actual:   ${actual_sha256}"
        exit 1
    fi

    tar -C "$destination_path" -xzf "$temp_tarball" --strip-components=1
}

echo -e "${BLUE}    LOG:${YELLOW} Setting up Go and GVM in ${GVM_ROOT}...${NC}"

if [ ! -d "$GVM_ROOT/scripts" ]; then
    echo -e "${BLUE}    LOG:${YELLOW} Cloning GVM...${NC}"
    git clone https://github.com/moovweb/gvm.git "$GVM_ROOT"
    rm -rf "$GVM_ROOT/.git"
    echo -e "${BLUE}    LOG:${YELLOW} Configuring GVM scripts...${NC}"
    cp "$GVM_ROOT/scripts/gvm-default" "$GVM_ROOT/scripts/gvm"
    python3 - "$GVM_ROOT/scripts/gvm" "$GVM_ROOT" <<'PY'
from pathlib import Path
import sys

path = Path(sys.argv[1])
root = sys.argv[2]
text = path.read_text()
path.write_text(text.replace('GVM_ROOT="$HOME/.gvm"', f'GVM_ROOT="{root}"', 1))
PY
    
    echo -e "${GREEN}    SUCCESS:${NC} GVM cloned and configured."
else
    echo -e "${GREEN}    SKIP:${NC} GVM already installed."
fi

if [ ! -d "$BOOTSTRAP_GO" ]; then
    mkdir -p "$BOOTSTRAP_GO"
    download_and_verify_go_bootstrap "$BOOTSTRAP_GO"
    
    echo -e "${GREEN}    SUCCESS:${NC} Bootstrap Go installed."
else
    echo -e "${GREEN}    SKIP:${NC} Bootstrap Go already exists."
fi

export PATH="$BOOTSTRAP_GO/bin:$PATH"
export GOROOT_BOOTSTRAP="$BOOTSTRAP_GO"

set +e
source "$GVM_ROOT/scripts/gvm"
set -e

if ! command -v gvm &> /dev/null; then
    echo -e "${RED}    ERROR:${NC} GVM failed to load."
    exit 1
fi

TARGET_VER="go1.24.11"

if ! gvm list | grep -q "$TARGET_VER"; then
    echo -e "${BLUE}    LOG:${YELLOW} Installing ${TARGET_VER}...${NC}"
    gvm install "$TARGET_VER" --prefer-binary
fi

gvm use "$TARGET_VER" --default

echo -e "${GREEN}    SUCCESS:${NC} Go setup completed."