// Path: Backend/internal/bootstrap/project_order.go

package bootstrap

import (
	"fmt"
	"path/filepath"
	"sort"
	"strings"
)

func (service *Service) readProjectFolderOrder(projectSlug, rootProjectionPath string) map[string][]string {
	settingsPath := service.projectSettingsPath(projectSlug)
	settingsPayload := readStructuredFileMap(settingsPath)
	folderOrderPayload, _ := settingsPayload["folderOrder"].(map[string]any)
	if folderOrderPayload == nil {
		return map[string][]string{}
	}
	scopePayload, _ := folderOrderPayload[projectFolderOrderScope(rootProjectionPath)].(map[string]any)
	if scopePayload == nil {
		return map[string][]string{}
	}
	byParentPayload, _ := scopePayload["byParent"].(map[string]any)
	if byParentPayload == nil {
		return map[string][]string{}
	}
	order := make(map[string][]string, len(byParentPayload))
	for key, raw := range byParentPayload {
		for _, id := range stringSliceValue(raw) {
			trimmedID := strings.TrimSpace(id)
			if trimmedID == "" || slicesContains(order[key], trimmedID) {
				continue
			}
			order[key] = append(order[key], trimmedID)
		}
	}
	return order
}

func (service *Service) writeProjectFolderOrder(projectSlug, rootProjectionPath string, folderOrder map[string][]string) error {
	settingsPath := service.projectSettingsPath(projectSlug)
	settingsPayload := readStructuredFileMap(settingsPath)
	if settingsPayload == nil {
		settingsPayload = map[string]any{}
	}
	folderOrderPayload, _ := settingsPayload["folderOrder"].(map[string]any)
	if folderOrderPayload == nil {
		folderOrderPayload = map[string]any{}
	}
	scopeKey := projectFolderOrderScope(rootProjectionPath)
	scopePayload, _ := folderOrderPayload[scopeKey].(map[string]any)
	if scopePayload == nil {
		scopePayload = map[string]any{}
	}
	byParentPayload := map[string]any{}
	for key, ids := range folderOrder {
		if len(ids) == 0 {
			continue
		}
		copied := make([]string, 0, len(ids))
		for _, id := range ids {
			trimmedID := strings.TrimSpace(id)
			if trimmedID == "" || slicesContains(copied, trimmedID) {
				continue
			}
			copied = append(copied, trimmedID)
		}
		if len(copied) > 0 {
			byParentPayload[key] = copied
		}
	}
	scopePayload["byParent"] = byParentPayload
	folderOrderPayload[scopeKey] = scopePayload
	settingsPayload["folderOrder"] = folderOrderPayload
	if err := writeCBORFile(settingsPath, settingsPayload); err != nil {
		return fmt.Errorf("write project %s: %w", posixSettingsFileName, err)
	}
	return nil
}

func (service *Service) projectSettingsPath(projectSlug string) string {
	return filepath.Join(strings.TrimSpace(service.posixRoot), "projects", slugDir("project", projectSlug), posixSettingsFileName)
}

func projectFolderOrderScope(rootProjectionPath string) string {
	if strings.HasSuffix(rootProjectionPath, "/tree") {
		return projectFolderOrderTree
	}
	return projectFolderOrderHierarchy
}

func applyProjectHierarchyFolderOrdering(folders []ProjectHierarchyFolderRecord, folderOrder map[string][]string) []ProjectHierarchyFolderRecord {
	return applyProjectHierarchyFolderOrderingForParent(folders, "", folderOrder)
}

func applyProjectHierarchyFolderOrderingForParent(folders []ProjectHierarchyFolderRecord, parentID string, folderOrder map[string][]string) []ProjectHierarchyFolderRecord {
	if len(folders) == 0 {
		return folders
	}
	nextFolders := make([]ProjectHierarchyFolderRecord, len(folders))
	copy(nextFolders, folders)
	for index := range nextFolders {
		nextFolders[index].Children = applyProjectHierarchyFolderOrderingForParent(nextFolders[index].Children, nextFolders[index].ID, folderOrder)
	}
	orderIDs := folderOrder[projectFolderOrderParentKey(parentID)]
	if len(orderIDs) == 0 {
		return nextFolders
	}
	rankByID := make(map[string]int, len(orderIDs))
	for index, id := range orderIDs {
		if _, exists := rankByID[id]; !exists {
			rankByID[id] = index
		}
	}
	sort.SliceStable(nextFolders, func(left, right int) bool {
		leftRank, leftOrdered := rankByID[nextFolders[left].ID]
		rightRank, rightOrdered := rankByID[nextFolders[right].ID]
		if leftOrdered && rightOrdered {
			return leftRank < rightRank
		}
		if leftOrdered != rightOrdered {
			return leftOrdered
		}
		return false
	})
	return nextFolders
}

func removeFolderOrder(folderOrder map[string][]string, folderID string) {
	removeFolderOrderReference(folderOrder, folderID)
	trimmedFolderID := strings.TrimSpace(folderID)
	if trimmedFolderID == "" {
		return
	}
	delete(folderOrder, projectFolderOrderParentKey(trimmedFolderID))
}

func removeFolderOrderReference(folderOrder map[string][]string, folderID string) {
	trimmedFolderID := strings.TrimSpace(folderID)
	if trimmedFolderID == "" {
		return
	}
	for key, ids := range folderOrder {
		nextIDs := ids[:0]
		for _, id := range ids {
			if strings.TrimSpace(id) == trimmedFolderID {
				continue
			}
			nextIDs = append(nextIDs, id)
		}
		if len(nextIDs) == 0 {
			delete(folderOrder, key)
			continue
		}
		folderOrder[key] = append([]string(nil), nextIDs...)
	}
}

func insertFolderOrder(folderOrder map[string][]string, parentID, folderID string, index int) {
	trimmedFolderID := strings.TrimSpace(folderID)
	if trimmedFolderID == "" {
		return
	}
	removeFolderOrderReference(folderOrder, trimmedFolderID)
	parentKey := projectFolderOrderParentKey(parentID)
	children := append([]string(nil), folderOrder[parentKey]...)
	if index < 0 {
		index = 0
	}
	if index > len(children) {
		index = len(children)
	}
	children = slicesInsert(children, index, trimmedFolderID)
	folderOrder[parentKey] = children
}

func seedFolderOrderParent(folderOrder map[string][]string, folders []ProjectHierarchyFolderRecord, parentID string) {
	children := folders
	trimmedParentID := strings.TrimSpace(parentID)
	if trimmedParentID != "" {
		parent, found := findProjectHierarchyFolder(folders, trimmedParentID)
		if !found {
			return
		}
		children = parent.Children
	}
	parentKey := projectFolderOrderParentKey(trimmedParentID)
	seeded := make([]string, 0, len(children))
	for _, child := range children {
		childID := strings.TrimSpace(child.ID)
		if childID == "" || slicesContains(seeded, childID) {
			continue
		}
		seeded = append(seeded, childID)
	}
	if len(seeded) == 0 {
		delete(folderOrder, parentKey)
		return
	}
	folderOrder[parentKey] = seeded
}

func folderOrderChildren(folderOrder map[string][]string, parentID string) []string {
	return append([]string(nil), folderOrder[projectFolderOrderParentKey(parentID)]...)
}

func projectFolderOrderParentKey(parentID string) string {
	trimmedParentID := strings.TrimSpace(parentID)
	if trimmedParentID == "" {
		return projectFolderOrderRootKey
	}
	return trimmedParentID
}

func stringSliceValue(value any) []string {
	items, ok := value.([]any)
	if !ok {
		if typed, ok := value.([]string); ok {
			return typed
		}
		return nil
	}
	result := make([]string, 0, len(items))
	for _, item := range items {
		if text, ok := item.(string); ok {
			result = append(result, text)
		}
	}
	return result
}

func slicesContains(values []string, value string) bool {
	for _, existing := range values {
		if existing == value {
			return true
		}
	}
	return false
}

func slicesInsert(values []string, index int, value string) []string {
	values = append(values, "")
	copy(values[index+1:], values[index:])
	values[index] = value
	return values
}

func buildProjectHierarchyFolderTree(rows []projectHierarchyFolderRow, rootParentPath string) []ProjectHierarchyFolderRecord {
	if len(rows) == 0 {
		return nil
	}
	nodesByPath := make(map[string]*ProjectHierarchyFolderRecord, len(rows))
	childrenByParent := make(map[string][]string)
	for _, row := range rows {
		folderID := strings.TrimSpace(row.ID)
		if folderID == "" {
			folderID = row.Path
		}
		label := strings.TrimSpace(row.Label)
		if label == "" {
			label = fallbackFolderLabel(row.Path)
		}
		nodesByPath[row.Path] = &ProjectHierarchyFolderRecord{ID: folderID, Path: row.Path, Label: label, Children: []ProjectHierarchyFolderRecord{}}
		childrenByParent[row.ParentPath] = append(childrenByParent[row.ParentPath], row.Path)
	}
	var build func(parentPath string) []ProjectHierarchyFolderRecord
	build = func(parentPath string) []ProjectHierarchyFolderRecord {
		childPaths := childrenByParent[parentPath]
		if len(childPaths) == 0 {
			return nil
		}
		folders := make([]ProjectHierarchyFolderRecord, 0, len(childPaths))
		for _, childPath := range childPaths {
			node := nodesByPath[childPath]
			if node == nil {
				continue
			}
			folder := ProjectHierarchyFolderRecord{ID: node.ID, Path: node.Path, Label: node.Label, Children: build(filepath.ToSlash(filepath.Join(childPath, "children")))}
			folders = append(folders, folder)
		}
		return folders
	}
	return build(rootParentPath)
}

func buildProjectTreeNodeTree(rows []projectTreeNodeRow, rootParentPath string) []ProjectTreeNodeRecord {
	if len(rows) == 0 {
		return nil
	}
	nodesByPath := make(map[string]*ProjectTreeNodeRecord, len(rows))
	childrenByParent := make(map[string][]string)
	for _, row := range rows {
		nodeKind := normalizeProjectTreeNodeKind(row.Kind)
		nodeID := strings.TrimSpace(row.ID)
		if nodeID == "" {
			nodeID = row.Path
		}
		label := strings.TrimSpace(row.Label)
		if label == "" {
			if nodeKind == "item" {
				label = fallbackItemLabel(row.Path)
			} else {
				label = fallbackFolderLabel(row.Path)
			}
		}
		nodesByPath[row.Path] = &ProjectTreeNodeRecord{ID: nodeID, Path: row.Path, Label: label, Kind: nodeKind, ItemType: normalizeProjectTreeItemType(row.ItemType), Children: []ProjectTreeNodeRecord{}}
		parentKey := normalizeProjectTreeParentPath(nodeKind, row.ParentPath)
		childrenByParent[parentKey] = append(childrenByParent[parentKey], row.Path)
	}
	var build func(parentPath string) []ProjectTreeNodeRecord
	build = func(parentPath string) []ProjectTreeNodeRecord {
		childPaths := childrenByParent[parentPath]
		if len(childPaths) == 0 {
			return nil
		}
		nodes := make([]ProjectTreeNodeRecord, 0, len(childPaths))
		for _, childPath := range childPaths {
			node := nodesByPath[childPath]
			if node == nil {
				continue
			}
			nextNode := ProjectTreeNodeRecord{ID: node.ID, Path: node.Path, Label: node.Label, Kind: node.Kind, ItemType: node.ItemType}
			if node.Kind == "folder" {
				nextNode.Children = build(node.Path)
			}
			nodes = append(nodes, nextNode)
		}
		return nodes
	}
	return build(rootParentPath)
}

func normalizeProjectTreeParentPath(kind, parentPath string) string {
	if kind == "folder" && strings.HasSuffix(parentPath, "/children") {
		return filepath.ToSlash(filepath.Dir(parentPath))
	}
	return parentPath
}

func normalizeProjectTreeNodeKind(kind string) string {
	switch strings.TrimSpace(kind) {
	case "item":
		return "item"
	case "folder", "hierarchy_folder":
		return "folder"
	default:
		return "folder"
	}
}

func applyProjectTreeNodeOrdering(nodes []ProjectTreeNodeRecord, folderOrder map[string][]string) []ProjectTreeNodeRecord {
	return applyProjectTreeNodeOrderingForParent(nodes, "", folderOrder)
}

func applyProjectTreeNodeOrderingForParent(nodes []ProjectTreeNodeRecord, parentID string, folderOrder map[string][]string) []ProjectTreeNodeRecord {
	if len(nodes) == 0 {
		return nodes
	}
	nextNodes := make([]ProjectTreeNodeRecord, len(nodes))
	copy(nextNodes, nodes)
	for index := range nextNodes {
		if nextNodes[index].Kind == "folder" {
			nextNodes[index].Children = applyProjectTreeNodeOrderingForParent(nextNodes[index].Children, nextNodes[index].ID, folderOrder)
		}
	}
	orderIDs := folderOrder[projectFolderOrderParentKey(parentID)]
	if len(orderIDs) == 0 {
		return nextNodes
	}
	rankByID := make(map[string]int, len(orderIDs))
	for index, id := range orderIDs {
		if _, exists := rankByID[id]; !exists {
			rankByID[id] = index
		}
	}
	sort.SliceStable(nextNodes, func(left, right int) bool {
		leftRank, leftOrdered := rankByID[nextNodes[left].ID]
		rightRank, rightOrdered := rankByID[nextNodes[right].ID]
		if leftOrdered && rightOrdered {
			return leftRank < rightRank
		}
		if leftOrdered != rightOrdered {
			return leftOrdered
		}
		return false
	})
	return nextNodes
}

func findProjectHierarchyFolder(folders []ProjectHierarchyFolderRecord, folderID string) (ProjectHierarchyFolderRecord, bool) {
	for _, folder := range folders {
		if folder.ID == folderID {
			return folder, true
		}
		if child, ok := findProjectHierarchyFolder(folder.Children, folderID); ok {
			return child, true
		}
	}
	return ProjectHierarchyFolderRecord{}, false
}

func findProjectHierarchyFolderByPath(folders []ProjectHierarchyFolderRecord, folderPath string) (ProjectHierarchyFolderRecord, bool) {
	for _, folder := range folders {
		if folder.Path == folderPath {
			return folder, true
		}
		if child, ok := findProjectHierarchyFolderByPath(folder.Children, folderPath); ok {
			return child, true
		}
	}
	return ProjectHierarchyFolderRecord{}, false
}

func findProjectTreeNode(nodes []ProjectTreeNodeRecord, nodeID string) (ProjectTreeNodeRecord, bool) {
	for _, node := range nodes {
		if node.ID == nodeID {
			return node, true
		}
		if child, ok := findProjectTreeNode(node.Children, nodeID); ok {
			return child, true
		}
	}
	return ProjectTreeNodeRecord{}, false
}

func findProjectTreeNodeByPath(nodes []ProjectTreeNodeRecord, nodePath string) (ProjectTreeNodeRecord, bool) {
	for _, node := range nodes {
		if node.Path == nodePath {
			return node, true
		}
		if child, ok := findProjectTreeNodeByPath(node.Children, nodePath); ok {
			return child, true
		}
	}
	return ProjectTreeNodeRecord{}, false
}

func findProjectTreeFolderByPath(nodes []ProjectTreeNodeRecord, folderPath string) (ProjectTreeNodeRecord, bool) {
	node, ok := findProjectTreeNodeByPath(nodes, folderPath)
	if !ok || node.Kind != "folder" {
		return ProjectTreeNodeRecord{}, false
	}
	return node, true
}

func seedProjectTreeOrderParent(folderOrder map[string][]string, nodes []ProjectTreeNodeRecord, parentID string) {
	children := nodes
	trimmedParentID := strings.TrimSpace(parentID)
	if trimmedParentID != "" {
		parent, found := findProjectTreeNode(nodes, trimmedParentID)
		if !found || parent.Kind != "folder" {
			return
		}
		children = parent.Children
	}
	parentKey := projectFolderOrderParentKey(parentID)
	if len(folderOrder[parentKey]) > 0 {
		return
	}
	orderedIDs := make([]string, 0, len(children))
	for _, child := range children {
		trimmedChildID := strings.TrimSpace(child.ID)
		if trimmedChildID == "" || slicesContains(orderedIDs, trimmedChildID) {
			continue
		}
		orderedIDs = append(orderedIDs, trimmedChildID)
	}
	if len(orderedIDs) > 0 {
		folderOrder[parentKey] = orderedIDs
	}
}