package database

import (
	"database/sql"
	"fmt"
	"log"
	"sync"

	_ "github.com/mattn/go-sqlite3"
)

// DB wraps the database connection with mutex protection
type DB struct {
	db  *sql.DB
	mu  sync.Mutex
}

// NewDB creates a new database connection
func NewDB(dbPath string) (*DB, error) {
	db, err := sql.Open("sqlite3", dbPath)
	if err != nil {
		return nil, fmt.Errorf("failed to open database: %w", err)
	}

	if err := db.Ping(); err != nil {
		return nil, fmt.Errorf("failed to ping database: %w", err)
	}

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

	database := &DB{db: db}
	if err := database.migrate(); err != nil {
		return nil, fmt.Errorf("failed to migrate database: %w", err)
	}

	return database, nil
}

// With executes a function with mutex-protected access to the database
// The function receives the underlying *sql.DB connection
func (db *DB) With(fn func(*sql.DB) error) error {
	db.mu.Lock()
	defer db.mu.Unlock()
	return fn(db.db)
}

// WithTx executes a function within a transaction with mutex protection
// The function receives a *sql.Tx transaction
// If the function returns an error, the transaction is rolled back
// If the function returns nil, the transaction is committed
func (db *DB) WithTx(fn func(*sql.Tx) error) error {
	db.mu.Lock()
	defer db.mu.Unlock()

	tx, err := db.db.Begin()
	if err != nil {
		return fmt.Errorf("failed to begin transaction: %w", err)
	}

	if err := fn(tx); err != nil {
		if rbErr := tx.Rollback(); rbErr != nil {
			return fmt.Errorf("transaction error: %w, rollback error: %v", err, rbErr)
		}
		return err
	}

	if err := tx.Commit(); err != nil {
		return fmt.Errorf("failed to commit transaction: %w", err)
	}

	return nil
}

// migrate runs database migrations
func (db *DB) migrate() error {
	// SQLite uses INTEGER PRIMARY KEY AUTOINCREMENT instead of sequences
	schema := `
	CREATE TABLE IF NOT EXISTS users (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		email TEXT UNIQUE NOT NULL,
		name TEXT NOT NULL,
		oauth_provider TEXT NOT NULL,
		oauth_id TEXT NOT NULL,
		password_hash TEXT,
		is_admin INTEGER NOT NULL DEFAULT 0,
		created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
		UNIQUE(oauth_provider, oauth_id)
	);

	CREATE TABLE IF NOT EXISTS runner_api_keys (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		key_prefix TEXT NOT NULL,
		key_hash TEXT NOT NULL,
		name TEXT NOT NULL,
		description TEXT,
		scope TEXT NOT NULL DEFAULT 'user',
		is_active INTEGER NOT NULL DEFAULT 1,
		created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
		created_by INTEGER,
		FOREIGN KEY (created_by) REFERENCES users(id),
		UNIQUE(key_prefix)
	);

	CREATE TABLE IF NOT EXISTS jobs (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		user_id INTEGER NOT NULL,
		job_type TEXT NOT NULL DEFAULT 'render',
		name TEXT NOT NULL,
		status TEXT NOT NULL DEFAULT 'pending',
		progress REAL NOT NULL DEFAULT 0.0,
		frame_start INTEGER,
		frame_end INTEGER,
		output_format TEXT,
		allow_parallel_runners INTEGER NOT NULL DEFAULT 1,
		timeout_seconds INTEGER DEFAULT 86400,
		blend_metadata TEXT,
		retry_count INTEGER NOT NULL DEFAULT 0,
		max_retries INTEGER NOT NULL DEFAULT 3,
		created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
		started_at TIMESTAMP,
		completed_at TIMESTAMP,
		error_message TEXT,
		FOREIGN KEY (user_id) REFERENCES users(id)
	);

	CREATE TABLE IF NOT EXISTS runners (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		name TEXT NOT NULL,
		hostname TEXT NOT NULL,
		ip_address TEXT NOT NULL,
		status TEXT NOT NULL DEFAULT 'offline',
		last_heartbeat TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
		capabilities TEXT,
		api_key_id INTEGER,
		api_key_scope TEXT NOT NULL DEFAULT 'user',
		priority INTEGER NOT NULL DEFAULT 100,
		fingerprint TEXT,
		created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
		FOREIGN KEY (api_key_id) REFERENCES runner_api_keys(id)
	);

	CREATE TABLE IF NOT EXISTS tasks (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		job_id INTEGER NOT NULL,
		runner_id INTEGER,
		frame_start INTEGER NOT NULL,
		frame_end INTEGER NOT NULL,
		status TEXT NOT NULL DEFAULT 'pending',
		output_path TEXT,
		task_type TEXT NOT NULL DEFAULT 'render',
		current_step TEXT,
		retry_count INTEGER NOT NULL DEFAULT 0,
		max_retries INTEGER NOT NULL DEFAULT 3,
		timeout_seconds INTEGER,
		created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
		started_at TIMESTAMP,
		completed_at TIMESTAMP,
		error_message TEXT,
		FOREIGN KEY (job_id) REFERENCES jobs(id),
		FOREIGN KEY (runner_id) REFERENCES runners(id)
	);

	CREATE TABLE IF NOT EXISTS job_files (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		job_id INTEGER NOT NULL,
		file_type TEXT NOT NULL,
		file_path TEXT NOT NULL,
		file_name TEXT NOT NULL,
		file_size INTEGER NOT NULL,
		created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
		FOREIGN KEY (job_id) REFERENCES jobs(id)
	);

	CREATE TABLE IF NOT EXISTS manager_secrets (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		secret TEXT UNIQUE NOT NULL,
		created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
	);

	CREATE TABLE IF NOT EXISTS task_logs (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		task_id INTEGER NOT NULL,
		runner_id INTEGER,
		log_level TEXT NOT NULL,
		message TEXT NOT NULL,
		step_name TEXT,
		created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
		FOREIGN KEY (task_id) REFERENCES tasks(id),
		FOREIGN KEY (runner_id) REFERENCES runners(id)
	);

	CREATE TABLE IF NOT EXISTS task_steps (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		task_id INTEGER NOT NULL,
		step_name TEXT NOT NULL,
		status TEXT NOT NULL DEFAULT 'pending',
		started_at TIMESTAMP,
		completed_at TIMESTAMP,
		duration_ms INTEGER,
		error_message TEXT,
		FOREIGN KEY (task_id) REFERENCES tasks(id)
	);

	CREATE INDEX IF NOT EXISTS idx_jobs_user_id ON jobs(user_id);
	CREATE INDEX IF NOT EXISTS idx_jobs_status ON jobs(status);
	CREATE INDEX IF NOT EXISTS idx_jobs_user_status_created ON jobs(user_id, status, created_at DESC);
	CREATE INDEX IF NOT EXISTS idx_tasks_job_id ON tasks(job_id);
	CREATE INDEX IF NOT EXISTS idx_tasks_runner_id ON tasks(runner_id);
	CREATE INDEX IF NOT EXISTS idx_tasks_status ON tasks(status);
	CREATE INDEX IF NOT EXISTS idx_tasks_job_status ON tasks(job_id, status);
	CREATE INDEX IF NOT EXISTS idx_tasks_started_at ON tasks(started_at);
	CREATE INDEX IF NOT EXISTS idx_job_files_job_id ON job_files(job_id);
	CREATE INDEX IF NOT EXISTS idx_runner_api_keys_prefix ON runner_api_keys(key_prefix);
	CREATE INDEX IF NOT EXISTS idx_runner_api_keys_active ON runner_api_keys(is_active);
	CREATE INDEX IF NOT EXISTS idx_runner_api_keys_created_by ON runner_api_keys(created_by);
	CREATE INDEX IF NOT EXISTS idx_runners_api_key_id ON runners(api_key_id);
	CREATE INDEX IF NOT EXISTS idx_task_logs_task_id_created_at ON task_logs(task_id, created_at);
	CREATE INDEX IF NOT EXISTS idx_task_logs_task_id_id ON task_logs(task_id, id DESC);
	CREATE INDEX IF NOT EXISTS idx_task_logs_runner_id ON task_logs(runner_id);
	CREATE INDEX IF NOT EXISTS idx_task_steps_task_id ON task_steps(task_id);
	CREATE INDEX IF NOT EXISTS idx_runners_last_heartbeat ON runners(last_heartbeat);

	CREATE TABLE IF NOT EXISTS settings (
		key TEXT PRIMARY KEY,
		value TEXT NOT NULL,
		updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
	);

	CREATE TABLE IF NOT EXISTS sessions (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		session_id TEXT UNIQUE NOT NULL,
		user_id INTEGER NOT NULL,
		email TEXT NOT NULL,
		name TEXT NOT NULL,
		is_admin INTEGER NOT NULL DEFAULT 0,
		expires_at TIMESTAMP NOT NULL,
		created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
		FOREIGN KEY (user_id) REFERENCES users(id)
	);

	CREATE INDEX IF NOT EXISTS idx_sessions_session_id ON sessions(session_id);
	CREATE INDEX IF NOT EXISTS idx_sessions_user_id ON sessions(user_id);
	CREATE INDEX IF NOT EXISTS idx_sessions_expires_at ON sessions(expires_at);
	`

	if err := db.With(func(conn *sql.DB) error {
		_, err := conn.Exec(schema)
		return err
	}); err != nil {
		return fmt.Errorf("failed to create schema: %w", err)
	}

	// Database migrations for schema updates
	// NOTE: Migrations are currently disabled since the database is cleared by 'make cleanup-manager'
	// before running. All schema changes have been rolled into the main schema above.
	// When ready to implement proper migrations for production, uncomment and populate this array.
	// TODO: Implement proper database migration system for production use
	migrations := []string{
		// Future migrations will go here when we implement proper migration handling
	}

	for _, migration := range migrations {
		if err := db.With(func(conn *sql.DB) error {
			_, err := conn.Exec(migration)
			return err
		}); err != nil {
			// Log but don't fail - column might already exist or table might not exist yet
			// This is fine for migrations that run after schema creation
			log.Printf("Migration warning: %v", err)
		}
	}

	// Initialize registration_enabled setting (default: true) if it doesn't exist
	var settingCount int
	err := db.With(func(conn *sql.DB) error {
		return conn.QueryRow("SELECT COUNT(*) FROM settings WHERE key = ?", "registration_enabled").Scan(&settingCount)
	})
	if err == nil && settingCount == 0 {
		err = db.With(func(conn *sql.DB) error {
			_, err := conn.Exec("INSERT INTO settings (key, value) VALUES (?, ?)", "registration_enabled", "true")
			return err
		})
		if err != nil {
			// Log but don't fail - setting might have been created by another process
			log.Printf("Note: Could not initialize registration_enabled setting: %v", err)
		}
	}

	return nil
}

// Ping checks the database connection
func (db *DB) Ping() error {
	db.mu.Lock()
	defer db.mu.Unlock()
	return db.db.Ping()
}

// Close closes the database connection
func (db *DB) Close() error {
	db.mu.Lock()
	defer db.mu.Unlock()
	return db.db.Close()
}