package runner

import (
	"context"
	"errors"
	"fmt"
	"path/filepath"
	"strings"
	"sync"

	sqlite "zombiezen.com/go/sqlite"
	"zombiezen.com/go/sqlite/sqlitex"

	"Moonshark/utils/logger"

	luajit "git.sharkk.net/Sky/LuaJIT-to-Go"
)

// SQLiteConnection tracks an active connection
type SQLiteConnection struct {
	Conn *sqlite.Conn
	Pool *sqlitex.Pool
}

// SQLiteManager handles database connections
type SQLiteManager struct {
	mu          sync.RWMutex
	pools       map[string]*sqlitex.Pool
	activeConns map[string]*SQLiteConnection
	dataDir     string
}

var sqliteManager *SQLiteManager

// InitSQLite initializes the SQLite manager
func InitSQLite(dataDir string) {
	sqliteManager = &SQLiteManager{
		pools:       make(map[string]*sqlitex.Pool),
		activeConns: make(map[string]*SQLiteConnection),
		dataDir:     dataDir,
	}
	logger.Server("SQLite initialized with data directory: %s", dataDir)
}

// CleanupSQLite closes all database connections
func CleanupSQLite() {
	if sqliteManager == nil {
		return
	}

	sqliteManager.mu.Lock()
	defer sqliteManager.mu.Unlock()

	for id, conn := range sqliteManager.activeConns {
		if conn.Pool != nil {
			conn.Pool.Put(conn.Conn)
		}
		delete(sqliteManager.activeConns, id)
	}

	for name, pool := range sqliteManager.pools {
		if err := pool.Close(); err != nil {
			logger.Error("Failed to close database %s: %v", name, err)
		}
	}

	sqliteManager.pools = nil
	sqliteManager.activeConns = nil
	logger.Debug("SQLite connections closed")
}

// ReleaseActiveConnections returns all active connections to their pools
func ReleaseActiveConnections(state *luajit.State) {
	if sqliteManager == nil {
		return
	}

	// Get active connections table from Lua
	state.GetGlobal("__active_sqlite_connections")
	if !state.IsTable(-1) {
		state.Pop(1)
		return
	}

	sqliteManager.mu.Lock()
	defer sqliteManager.mu.Unlock()

	// Iterate through active connections
	state.PushNil() // Start iteration
	for state.Next(-2) {
		if state.IsTable(-1) {
			state.GetField(-1, "id")
			if state.IsString(-1) {
				connID := state.ToString(-1)
				if conn, exists := sqliteManager.activeConns[connID]; exists {
					if conn.Pool != nil {
						conn.Pool.Put(conn.Conn)
					}
					delete(sqliteManager.activeConns, connID)
				}
			}
			state.Pop(1) // Pop connection id
		}
		state.Pop(1) // Pop value, leave key for next iteration
	}

	// Clear the active connections table
	state.PushNil()
	state.SetGlobal("__active_sqlite_connections")
}

// getConnection returns a connection for the database
func getConnection(dbName, connID string) (*sqlite.Conn, error) {
	if sqliteManager == nil {
		return nil, errors.New("SQLite not initialized")
	}

	// Validate database name
	dbName = filepath.Base(dbName)
	if dbName == "" || dbName[0] == '.' {
		return nil, errors.New("invalid database name")
	}

	// Check for existing connection
	sqliteManager.mu.RLock()
	conn, exists := sqliteManager.activeConns[connID]
	if exists {
		sqliteManager.mu.RUnlock()
		return conn.Conn, nil
	}
	sqliteManager.mu.RUnlock()

	// Get or create pool under write lock
	sqliteManager.mu.Lock()
	defer sqliteManager.mu.Unlock()

	// Double-check if a connection was created while waiting for lock
	if conn, exists = sqliteManager.activeConns[connID]; exists {
		return conn.Conn, nil
	}

	// Get or create pool
	pool, exists := sqliteManager.pools[dbName]
	if !exists {
		dbPath := filepath.Join(sqliteManager.dataDir, dbName+".db")
		var err error
		pool, err = sqlitex.NewPool(dbPath, sqlitex.PoolOptions{})
		if err != nil {
			return nil, fmt.Errorf("failed to open database: %w", err)
		}
		sqliteManager.pools[dbName] = pool
	}

	// Get a connection
	dbConn, err := pool.Take(context.Background())
	if err != nil {
		return nil, fmt.Errorf("failed to get connection from pool: %w", err)
	}

	// Store connection
	sqliteManager.activeConns[connID] = &SQLiteConnection{
		Conn: dbConn,
		Pool: pool,
	}

	return dbConn, nil
}

// releaseConnection returns a connection to its pool
func releaseConnection(connID string) {
	if sqliteManager == nil {
		return
	}

	sqliteManager.mu.Lock()
	defer sqliteManager.mu.Unlock()

	conn, exists := sqliteManager.activeConns[connID]
	if !exists {
		return
	}

	if conn.Pool != nil {
		conn.Pool.Put(conn.Conn)
	}
	delete(sqliteManager.activeConns, connID)
}

// sqlQuery executes a SQL query and returns results
func sqlQuery(state *luajit.State) int {
	// Get required parameters
	if state.GetTop() < 2 || !state.IsString(1) || !state.IsString(2) {
		state.PushString("sqlite.query: requires database name and query")
		return -1
	}

	dbName := state.ToString(1)
	query := state.ToString(2)
	connID := fmt.Sprintf("temp_%p", &query)

	// Get connection
	conn, err := getConnection(dbName, connID)
	if err != nil {
		state.PushString(fmt.Sprintf("sqlite.query: %s", err.Error()))
		return -1
	}
	defer releaseConnection(connID)

	// Create execution options
	var execOpts sqlitex.ExecOptions
	rows := make([]map[string]any, 0, 16)

	// Set up parameters if provided
	if state.GetTop() >= 3 && !state.IsNil(3) {
		if state.IsTable(3) {
			params, err := state.ToTable(3)
			if err != nil {
				state.PushString(fmt.Sprintf("sqlite.query: invalid parameters: %s", err.Error()))
				return -1
			}

			// Check for array-style params
			if arr, ok := params[""]; ok {
				if arrParams, ok := arr.([]any); ok {
					execOpts.Args = arrParams
				} else if floatArr, ok := arr.([]float64); ok {
					args := make([]any, len(floatArr))
					for i, v := range floatArr {
						args[i] = v
					}
					execOpts.Args = args
				}
			} else {
				// Named parameters
				named := make(map[string]any, len(params))
				for k, v := range params {
					if len(k) > 0 && k[0] != ':' {
						named[":"+k] = v
					} else {
						named[k] = v
					}
				}
				execOpts.Named = named
			}
		} else {
			// Positional parameters
			count := state.GetTop() - 2
			args := make([]any, count)
			for i := range count {
				idx := i + 3
				switch state.GetType(idx) {
				case luajit.TypeNumber:
					args[i] = state.ToNumber(idx)
				case luajit.TypeString:
					args[i] = state.ToString(idx)
				case luajit.TypeBoolean:
					args[i] = state.ToBoolean(idx)
				case luajit.TypeNil:
					args[i] = nil
				default:
					val, err := state.ToValue(idx)
					if err != nil {
						state.PushString(fmt.Sprintf("sqlite.query: invalid parameter %d: %s", i+1, err.Error()))
						return -1
					}
					args[i] = val
				}
			}
			execOpts.Args = args
		}
	}

	// Set up result function
	execOpts.ResultFunc = func(stmt *sqlite.Stmt) error {
		row := make(map[string]any)
		colCount := stmt.ColumnCount()

		for i := range colCount {
			colName := stmt.ColumnName(i)
			switch stmt.ColumnType(i) {
			case sqlite.TypeInteger:
				row[colName] = stmt.ColumnInt64(i)
			case sqlite.TypeFloat:
				row[colName] = stmt.ColumnFloat(i)
			case sqlite.TypeText:
				row[colName] = stmt.ColumnText(i)
			case sqlite.TypeBlob:
				blobSize := stmt.ColumnLen(i)
				buf := make([]byte, blobSize)
				row[colName] = stmt.ColumnBytes(i, buf)
			case sqlite.TypeNull:
				row[colName] = nil
			}
		}
		rows = append(rows, row)
		return nil
	}

	// Execute query
	if err := sqlitex.Execute(conn, query, &execOpts); err != nil {
		state.PushString(fmt.Sprintf("sqlite.query: %s", err.Error()))
		return -1
	}

	// Create result table
	state.NewTable()
	for i, row := range rows {
		state.PushNumber(float64(i + 1))
		if err := state.PushTable(row); err != nil {
			state.PushString(fmt.Sprintf("sqlite.query: %s", err.Error()))
			return -1
		}
		state.SetTable(-3)
	}

	return 1
}

// sqlExec executes a SQL statement without returning results
func sqlExec(state *luajit.State) int {
	// Get required parameters
	if state.GetTop() < 2 || !state.IsString(1) || !state.IsString(2) {
		state.PushString("sqlite.exec: requires database name and query")
		return -1
	}

	dbName := state.ToString(1)
	query := state.ToString(2)
	connID := fmt.Sprintf("temp_%p", &query)

	// Get connection
	conn, err := getConnection(dbName, connID)
	if err != nil {
		state.PushString(fmt.Sprintf("sqlite.exec: %s", err.Error()))
		return -1
	}
	defer releaseConnection(connID)

	// Check if parameters are provided
	hasParams := state.GetTop() >= 3 && !state.IsNil(3)

	// Fast path for multi-statement scripts - use ExecScript
	if strings.Contains(query, ";") && !hasParams {
		if err := sqlitex.ExecScript(conn, query); err != nil {
			state.PushString(fmt.Sprintf("sqlite.exec: %s", err.Error()))
			return -1
		}
		state.PushNumber(float64(conn.Changes()))
		return 1
	}

	// Fast path for simple queries with no parameters
	if !hasParams {
		// Use Execute for simple statements without parameters
		if err := sqlitex.Execute(conn, query, nil); err != nil {
			state.PushString(fmt.Sprintf("sqlite.exec: %s", err.Error()))
			return -1
		}
		state.PushNumber(float64(conn.Changes()))
		return 1
	}

	// Create execution options for parameterized query
	var execOpts sqlitex.ExecOptions

	// Set up parameters
	if state.IsTable(3) {
		params, err := state.ToTable(3)
		if err != nil {
			state.PushString(fmt.Sprintf("sqlite.exec: invalid parameters: %s", err.Error()))
			return -1
		}

		// Check for array-style params
		if arr, ok := params[""]; ok {
			if arrParams, ok := arr.([]any); ok {
				execOpts.Args = arrParams
			} else if floatArr, ok := arr.([]float64); ok {
				args := make([]any, len(floatArr))
				for i, v := range floatArr {
					args[i] = v
				}
				execOpts.Args = args
			}
		} else {
			// Named parameters
			named := make(map[string]any, len(params))
			for k, v := range params {
				if len(k) > 0 && k[0] != ':' {
					named[":"+k] = v
				} else {
					named[k] = v
				}
			}
			execOpts.Named = named
		}
	} else {
		// Positional parameters
		count := state.GetTop() - 2
		args := make([]any, count)
		for i := range count {
			idx := i + 3
			switch state.GetType(idx) {
			case luajit.TypeNumber:
				args[i] = state.ToNumber(idx)
			case luajit.TypeString:
				args[i] = state.ToString(idx)
			case luajit.TypeBoolean:
				args[i] = state.ToBoolean(idx)
			case luajit.TypeNil:
				args[i] = nil
			default:
				val, err := state.ToValue(idx)
				if err != nil {
					state.PushString(fmt.Sprintf("sqlite.exec: invalid parameter %d: %s", i+1, err.Error()))
					return -1
				}
				args[i] = val
			}
		}
		execOpts.Args = args
	}

	// Execute with parameters
	if err := sqlitex.Execute(conn, query, &execOpts); err != nil {
		state.PushString(fmt.Sprintf("sqlite.exec: %s", err.Error()))
		return -1
	}

	// Return affected rows
	state.PushNumber(float64(conn.Changes()))
	return 1
}

// RegisterSQLiteFunctions registers SQLite functions with the Lua state
func RegisterSQLiteFunctions(state *luajit.State) error {
	if err := state.RegisterGoFunction("__sqlite_query", sqlQuery); err != nil {
		return err
	}
	return state.RegisterGoFunction("__sqlite_exec", sqlExec)
}