package store

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"log"
	"os"
	"path/filepath"
	"sort"
	"time"

	_ "github.com/mattn/go-sqlite3"
	"task-dashboard/internal/models"
)

// Cache key constants
const (
	CacheKeyTodoistTasks   = "todoist_tasks"
	CacheKeyTrelloBoards   = "trello_boards"
	CacheKeyPlanToEatMeals = "plantoeat_meals"
)

type Store struct {
	db           *sql.DB
	migrationDir string
}

// New creates a new Store instance and runs migrations
func New(dbPath, migrationDir string) (*Store, error) {
	db, err := sql.Open("sqlite3", dbPath)
	if err != nil {
		return nil, fmt.Errorf("failed to open database: %w", err)
	}

	// Enable foreign keys
	if _, err := db.Exec("PRAGMA foreign_keys = ON"); err != nil {
		return nil, fmt.Errorf("failed to enable foreign keys: %w", err)
	}

	// Enable WAL mode for better concurrency
	if _, err := db.Exec("PRAGMA journal_mode = WAL"); err != nil {
		return nil, fmt.Errorf("failed to enable WAL mode: %w", err)
	}

	// Configure connection pool for SQLite with WAL mode
	// WAL allows concurrent reads, but writes still need serialization
	db.SetMaxOpenConns(5)
	db.SetMaxIdleConns(2)
	db.SetConnMaxLifetime(time.Hour)

	store := &Store{db: db, migrationDir: migrationDir}

	// Run migrations
	if err := store.runMigrations(); err != nil {
		return nil, fmt.Errorf("failed to run migrations: %w", err)
	}

	return store, nil
}

// Close closes the database connection
func (s *Store) Close() error {
	return s.db.Close()
}

// DB returns the underlying database connection
func (s *Store) DB() *sql.DB {
	return s.db
}

// runMigrations executes all migration files in order
func (s *Store) runMigrations() error {
	// Get migration files from configured directory
	pattern := filepath.Join(s.migrationDir, "*.sql")
	migrationFiles, err := filepath.Glob(pattern)
	if err != nil {
		return fmt.Errorf("failed to read migration files: %w", err)
	}

	// Sort migrations by filename
	sort.Strings(migrationFiles)

	// Execute each migration
	for _, file := range migrationFiles {
		content, err := os.ReadFile(file)
		if err != nil {
			return fmt.Errorf("failed to read migration %s: %w", file, err)
		}

		if _, err := s.db.Exec(string(content)); err != nil {
			return fmt.Errorf("failed to execute migration %s: %w", file, err)
		}
	}

	return nil
}

// Tasks operations

// SaveTasks saves multiple tasks to the database
func (s *Store) SaveTasks(tasks []models.Task) error {
	tx, err := s.db.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()

	// Clear existing tasks first to remove stale data
	if _, err := tx.Exec(`DELETE FROM tasks`); err != nil {
		return err
	}

	stmt, err := tx.Prepare(`
		INSERT OR REPLACE INTO tasks
		(id, content, description, project_id, project_name, due_date, priority, completed, labels, url, created_at, updated_at)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, CURRENT_TIMESTAMP)
	`)
	if err != nil {
		return err
	}
	defer stmt.Close()

	for _, task := range tasks {
		labelsJSON, _ := json.Marshal(task.Labels)
		_, err := stmt.Exec(
			task.ID,
			task.Content,
			task.Description,
			task.ProjectID,
			task.ProjectName,
			task.DueDate,
			task.Priority,
			task.Completed,
			string(labelsJSON),
			task.URL,
			task.CreatedAt,
		)
		if err != nil {
			return err
		}
	}

	return tx.Commit()
}

// GetTasks retrieves all tasks from the database
func (s *Store) GetTasks() ([]models.Task, error) {
	rows, err := s.db.Query(`
		SELECT id, content, description, project_id, project_name, due_date, priority, completed, labels, url, created_at
		FROM tasks
		ORDER BY completed ASC, CASE WHEN due_date IS NULL THEN 1 ELSE 0 END, due_date ASC, priority DESC
	`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var tasks []models.Task
	for rows.Next() {
		var task models.Task
		var labelsJSON string
		var dueDate sql.NullTime

		err := rows.Scan(
			&task.ID,
			&task.Content,
			&task.Description,
			&task.ProjectID,
			&task.ProjectName,
			&dueDate,
			&task.Priority,
			&task.Completed,
			&labelsJSON,
			&task.URL,
			&task.CreatedAt,
		)
		if err != nil {
			return nil, err
		}

		if dueDate.Valid {
			task.DueDate = &dueDate.Time
		}

		if err := json.Unmarshal([]byte(labelsJSON), &task.Labels); err != nil {
			log.Printf("Warning: failed to unmarshal labels for task %s: %v", task.ID, err)
			task.Labels = []string{}
		}
		tasks = append(tasks, task)
	}

	return tasks, rows.Err()
}

// DeleteTask removes a task from the cache by ID
func (s *Store) DeleteTask(id string) error {
	_, err := s.db.Exec(`DELETE FROM tasks WHERE id = ?`, id)
	return err
}

// UpsertTask inserts or updates a single task
func (s *Store) UpsertTask(task models.Task) error {
	labelsJSON, _ := json.Marshal(task.Labels)
	_, err := s.db.Exec(`
		INSERT OR REPLACE INTO tasks
		(id, content, description, project_id, project_name, due_date, priority, completed, labels, url, created_at, updated_at)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, CURRENT_TIMESTAMP)
	`,
		task.ID,
		task.Content,
		task.Description,
		task.ProjectID,
		task.ProjectName,
		task.DueDate,
		task.Priority,
		task.Completed,
		string(labelsJSON),
		task.URL,
		task.CreatedAt,
	)
	return err
}

// DeleteTasksByIDs removes multiple tasks by ID
func (s *Store) DeleteTasksByIDs(ids []string) error {
	if len(ids) == 0 {
		return nil
	}
	tx, err := s.db.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()

	stmt, err := tx.Prepare(`DELETE FROM tasks WHERE id = ?`)
	if err != nil {
		return err
	}
	defer stmt.Close()

	for _, id := range ids {
		if _, err := stmt.Exec(id); err != nil {
			return err
		}
	}
	return tx.Commit()
}

// Meals operations

// SaveMeals saves multiple meals to the database
func (s *Store) SaveMeals(meals []models.Meal) error {
	tx, err := s.db.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()

	stmt, err := tx.Prepare(`
		INSERT OR REPLACE INTO meals
		(id, recipe_name, date, meal_type, recipe_url, updated_at)
		VALUES (?, ?, ?, ?, ?, CURRENT_TIMESTAMP)
	`)
	if err != nil {
		return err
	}
	defer stmt.Close()

	for _, meal := range meals {
		_, err := stmt.Exec(
			meal.ID,
			meal.RecipeName,
			meal.Date,
			meal.MealType,
			meal.RecipeURL,
		)
		if err != nil {
			return err
		}
	}

	return tx.Commit()
}

// GetMeals retrieves meals from the database
func (s *Store) GetMeals(startDate, endDate time.Time) ([]models.Meal, error) {
	rows, err := s.db.Query(`
		SELECT id, recipe_name, date, meal_type, recipe_url
		FROM meals
		WHERE date BETWEEN ? AND ?
		ORDER BY date ASC,
			CASE meal_type
				WHEN 'breakfast' THEN 1
				WHEN 'lunch' THEN 2
				WHEN 'dinner' THEN 3
				ELSE 4
			END
	`, startDate, endDate)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var meals []models.Meal
	for rows.Next() {
		var meal models.Meal
		err := rows.Scan(
			&meal.ID,
			&meal.RecipeName,
			&meal.Date,
			&meal.MealType,
			&meal.RecipeURL,
		)
		if err != nil {
			return nil, err
		}
		meals = append(meals, meal)
	}

	return meals, rows.Err()
}

// Cache metadata operations

// GetCacheMetadata retrieves cache metadata for a key
func (s *Store) GetCacheMetadata(key string) (*models.CacheMetadata, error) {
	var cm models.CacheMetadata
	err := s.db.QueryRow(`
		SELECT key, last_fetch, ttl_minutes
		FROM cache_metadata
		WHERE key = ?
	`, key).Scan(&cm.Key, &cm.LastFetch, &cm.TTLMinutes)

	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	return &cm, nil
}

// UpdateCacheMetadata updates the last fetch time for a cache key
func (s *Store) UpdateCacheMetadata(key string, ttlMinutes int) error {
	_, err := s.db.Exec(`
		INSERT OR REPLACE INTO cache_metadata (key, last_fetch, ttl_minutes, updated_at)
		VALUES (?, CURRENT_TIMESTAMP, ?, CURRENT_TIMESTAMP)
	`, key, ttlMinutes)
	return err
}

// IsCacheValid checks if the cache for a given key is still valid
func (s *Store) IsCacheValid(key string) (bool, error) {
	cm, err := s.GetCacheMetadata(key)
	if err != nil {
		return false, err
	}
	if cm == nil {
		return false, nil
	}

	return cm.IsCacheValid(), nil
}

// InvalidateCache removes the cache metadata for a given key, forcing a refresh on next fetch
func (s *Store) InvalidateCache(key string) error {
	_, err := s.db.Exec(`DELETE FROM cache_metadata WHERE key = ?`, key)
	return err
}

// Boards operations

// SaveBoards saves multiple boards to the database
// This clears existing data and replaces it with the new data
func (s *Store) SaveBoards(boards []models.Board) error {
	tx, err := s.db.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()

	// Clear existing data first (cards must be deleted before boards due to foreign key)
	if _, err := tx.Exec(`DELETE FROM cards`); err != nil {
		return err
	}
	if _, err := tx.Exec(`DELETE FROM boards`); err != nil {
		return err
	}

	// Save boards
	boardStmt, err := tx.Prepare(`
		INSERT OR REPLACE INTO boards (id, name, updated_at)
		VALUES (?, ?, CURRENT_TIMESTAMP)
	`)
	if err != nil {
		return err
	}
	defer boardStmt.Close()

	// Save cards
	cardStmt, err := tx.Prepare(`
		INSERT OR REPLACE INTO cards
		(id, name, board_id, list_id, list_name, due_date, url, updated_at)
		VALUES (?, ?, ?, ?, ?, ?, ?, CURRENT_TIMESTAMP)
	`)
	if err != nil {
		return err
	}
	defer cardStmt.Close()

	savedBoards := 0
	savedCards := 0
	for _, board := range boards {
		_, err := boardStmt.Exec(board.ID, board.Name)
		if err != nil {
			log.Printf("Error saving board %s: %v", board.Name, err)
			return err
		}
		savedBoards++

		// Save all cards for this board
		for _, card := range board.Cards {
			_, err := cardStmt.Exec(
				card.ID,
				card.Name,
				board.ID,
				card.ListID,
				card.ListName,
				card.DueDate,
				card.URL,
			)
			if err != nil {
				log.Printf("Error saving card %s for board %s: %v", card.Name, board.Name, err)
				return err
			}
			savedCards++
		}
	}

	log.Printf("SaveBoards: Saved %d boards and %d cards to database", savedBoards, savedCards)
	return tx.Commit()
}

// GetBoards retrieves all boards with their cards from the database
func (s *Store) GetBoards() ([]models.Board, error) {
	// Fetch boards, sorted by: non-empty boards first, newest card activity, then alphabetical
	// Trello card IDs are chronologically sortable (newer IDs > older IDs)
	boardRows, err := s.db.Query(`
		SELECT b.id, b.name
		FROM boards b
		LEFT JOIN cards c ON c.board_id = b.id
		GROUP BY b.id, b.name
		ORDER BY
			CASE WHEN COUNT(c.id) > 0 THEN 0 ELSE 1 END,
			MAX(c.id) DESC,
			b.name ASC
	`)
	if err != nil {
		return nil, err
	}
	defer boardRows.Close()

	var boards []models.Board
	boardMap := make(map[string]int) // Store index, not pointer

	for boardRows.Next() {
		var board models.Board
		err := boardRows.Scan(&board.ID, &board.Name)
		if err != nil {
			return nil, err
		}
		board.Cards = []models.Card{}
		boardMap[board.ID] = len(boards) // Store index before append
		boards = append(boards, board)
	}

	if err := boardRows.Err(); err != nil {
		return nil, err
	}

	// Fetch cards
	cardRows, err := s.db.Query(`
		SELECT id, name, board_id, list_id, list_name, due_date, url
		FROM cards
		ORDER BY board_id, list_name, name
	`)
	if err != nil {
		return nil, err
	}
	defer cardRows.Close()

	for cardRows.Next() {
		var card models.Card
		var boardID string
		var dueDate sql.NullTime

		err := cardRows.Scan(
			&card.ID,
			&card.Name,
			&boardID,
			&card.ListID,
			&card.ListName,
			&dueDate,
			&card.URL,
		)
		if err != nil {
			return nil, err
		}

		if dueDate.Valid {
			card.DueDate = &dueDate.Time
		}

		// Add card to the appropriate board
		if idx, ok := boardMap[boardID]; ok {
			boards[idx].Cards = append(boards[idx].Cards, card)
		}
	}

	totalCards := 0
	for _, b := range boards {
		totalCards += len(b.Cards)
	}
	log.Printf("GetBoards: Retrieved %d boards with %d total cards from database", len(boards), totalCards)

	return boards, cardRows.Err()
}

// DeleteCard removes a card from the cache by ID
func (s *Store) DeleteCard(id string) error {
	_, err := s.db.Exec(`DELETE FROM cards WHERE id = ?`, id)
	return err
}

// Sync token operations

// GetSyncToken retrieves the sync token for a service
func (s *Store) GetSyncToken(service string) (string, error) {
	var token string
	err := s.db.QueryRow(`SELECT token FROM sync_tokens WHERE service = ?`, service).Scan(&token)
	if err == sql.ErrNoRows {
		return "", nil
	}
	if err != nil {
		return "", err
	}
	return token, nil
}

// SetSyncToken saves the sync token for a service
func (s *Store) SetSyncToken(service, token string) error {
	_, err := s.db.Exec(`
		INSERT OR REPLACE INTO sync_tokens (service, token, updated_at)
		VALUES (?, ?, CURRENT_TIMESTAMP)
	`, service, token)
	return err
}

// ClearSyncToken removes the sync token for a service
func (s *Store) ClearSyncToken(service string) error {
	_, err := s.db.Exec(`DELETE FROM sync_tokens WHERE service = ?`, service)
	return err
}

// Bug represents a user-reported bug
type Bug struct {
	ID          int64
	Description string
	CreatedAt   time.Time
}

// SaveBug saves a new bug report
func (s *Store) SaveBug(description string) error {
	_, err := s.db.Exec(`INSERT INTO bugs (description) VALUES (?)`, description)
	return err
}

// GetBugs retrieves all bugs, newest first
func (s *Store) GetBugs() ([]Bug, error) {
	rows, err := s.db.Query(`SELECT id, description, created_at FROM bugs ORDER BY created_at DESC`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var bugs []Bug
	for rows.Next() {
		var b Bug
		if err := rows.Scan(&b.ID, &b.Description, &b.CreatedAt); err != nil {
			return nil, err
		}
		bugs = append(bugs, b)
	}
	return bugs, rows.Err()
}

// GetTasksByDateRange retrieves tasks due within a specific date range
func (s *Store) GetTasksByDateRange(start, end time.Time) ([]models.Task, error) {
	rows, err := s.db.Query(`
		SELECT id, content, description, project_id, project_name, due_date, priority, completed, labels, url, created_at
		FROM tasks
		WHERE due_date BETWEEN ? AND ?
		ORDER BY due_date ASC, priority DESC
	`, start, end)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var tasks []models.Task
	for rows.Next() {
		var task models.Task
		var labelsJSON string
		var dueDate sql.NullTime

		err := rows.Scan(
			&task.ID,
			&task.Content,
			&task.Description,
			&task.ProjectID,
			&task.ProjectName,
			&dueDate,
			&task.Priority,
			&task.Completed,
			&labelsJSON,
			&task.URL,
			&task.CreatedAt,
		)
		if err != nil {
			return nil, err
		}

		if dueDate.Valid {
			task.DueDate = &dueDate.Time
		}

		if err := json.Unmarshal([]byte(labelsJSON), &task.Labels); err != nil {
			log.Printf("Warning: failed to unmarshal labels for task %s: %v", task.ID, err)
			task.Labels = []string{}
		}
		tasks = append(tasks, task)
	}

	return tasks, rows.Err()
}

// GetMealsByDateRange retrieves meals within a specific date range
func (s *Store) GetMealsByDateRange(start, end time.Time) ([]models.Meal, error) {
	return s.GetMeals(start, end)
}

// GetCardsByDateRange retrieves cards due within a specific date range
func (s *Store) GetCardsByDateRange(start, end time.Time) ([]models.Card, error) {
	rows, err := s.db.Query(`
		SELECT c.id, c.name, b.name, c.list_id, c.list_name, c.due_date, c.url
		FROM cards c
		JOIN boards b ON c.board_id = b.id
		WHERE c.due_date BETWEEN ? AND ?
		ORDER BY c.due_date ASC
	`, start, end)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var cards []models.Card
	for rows.Next() {
		var card models.Card
		var dueDate sql.NullTime

		err := rows.Scan(
			&card.ID,
			&card.Name,
			&card.BoardName,
			&card.ListID,
			&card.ListName,
			&dueDate,
			&card.URL,
		)
		if err != nil {
			return nil, err
		}

		if dueDate.Valid {
			card.DueDate = &dueDate.Time
		}

		cards = append(cards, card)
	}

	return cards, rows.Err()
}