package runner

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

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

	"Moonshark/core/utils/logger"

	"maps"

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

// SQLiteConnection tracks an active connection
type SQLiteConnection struct {
	DbName string
	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()

	// Release all connections and close pools
	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
	}

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

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

	// 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")
}

// getPool returns a connection pool for the specified database
func getPool(dbName string) (*sqlitex.Pool, 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 pool with read lock
	sqliteManager.mu.RLock()
	pool, exists := sqliteManager.pools[dbName]
	sqliteManager.mu.RUnlock()
	if exists {
		return pool, nil
	}

	// Create new pool with write lock
	sqliteManager.mu.Lock()
	defer sqliteManager.mu.Unlock()

	// Double check if another goroutine created it
	if pool, exists = sqliteManager.pools[dbName]; exists {
		return pool, nil
	}

	// Create database file path and pool
	dbPath := filepath.Join(sqliteManager.dataDir, dbName+".db")
	pool, err := sqlitex.NewPool(dbPath, sqlitex.PoolOptions{})
	if err != nil {
		return nil, fmt.Errorf("failed to open database: %w", err)
	}

	sqliteManager.pools[dbName] = pool
	return pool, nil
}

// getConnection returns a connection from the pool
func getConnection(dbName string, connID string) (*sqlite.Conn, *sqlitex.Pool, error) {
	// Check for existing connection first
	sqliteManager.mu.RLock()
	conn, exists := sqliteManager.activeConns[connID]
	sqliteManager.mu.RUnlock()

	if exists {
		return conn.Conn, conn.Pool, nil
	}

	// Get the pool
	pool, err := getPool(dbName)
	if err != nil {
		return nil, nil, err
	}

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

	// Store connection
	sqliteManager.mu.Lock()
	sqliteManager.activeConns[connID] = &SQLiteConnection{
		DbName: dbName,
		Conn:   dbConn,
		Pool:   pool,
	}
	sqliteManager.mu.Unlock()

	return dbConn, pool, nil
}

// processParams extracts parameters and connection ID from Lua state
func processParams(state *luajit.State, defaultConnID string) (params any, connID string, isPositional bool, positionalParams []any, err error) {
	connID = defaultConnID

	// Check if using positional parameters
	if state.GetTop() >= 3 && !state.IsTable(3) {
		isPositional = true
		paramCount := state.GetTop() - 2 // Count all args after db and query

		// Check if last param is a connection ID
		lastIdx := paramCount + 2 // db(1) + query(2) + paramCount
		if paramCount > 0 && state.IsString(lastIdx) && state.GetType(lastIdx-1) != state.GetType(lastIdx) {
			connID = state.ToString(lastIdx)
			paramCount-- // Exclude connID from param count
		}

		// Create array for positional parameters
		positionalParams = make([]any, paramCount)

		// Collect all parameters
		for i := 0; i < paramCount; i++ {
			paramIdx := i + 3 // Params start at index 3
			switch state.GetType(paramIdx) {
			case luajit.TypeNumber:
				positionalParams[i] = state.ToNumber(paramIdx)
			case luajit.TypeString:
				positionalParams[i] = state.ToString(paramIdx)
			case luajit.TypeBoolean:
				positionalParams[i] = state.ToBoolean(paramIdx)
			case luajit.TypeNil:
				positionalParams[i] = nil
			default:
				val, errConv := state.ToValue(paramIdx)
				if errConv != nil {
					return nil, "", false, nil, fmt.Errorf("failed to convert parameter %d: %w", i+1, errConv)
				}
				positionalParams[i] = val
			}
		}
		return nil, connID, isPositional, positionalParams, nil
	}

	// Named parameter handling
	if state.GetTop() >= 4 && !state.IsNil(4) && state.IsString(4) {
		connID = state.ToString(4)
	}

	// Get table parameters if present
	if state.GetTop() >= 3 && !state.IsNil(3) && state.IsTable(3) {
		params, err = state.ToTable(3)
	}

	return params, connID, isPositional, nil, err
}

// prepareExecOptions prepares SQLite execution options based on parameters
func prepareExecOptions(query string, params any, isPositional bool, positionalParams []any) *sqlitex.ExecOptions {
	execOpts := &sqlitex.ExecOptions{}

	if params == nil && !isPositional {
		return execOpts
	}

	// Prepare parameters
	isArray := false
	var namedParams map[string]any
	var arrParams []any

	// Check for array parameters
	if m, ok := params.(map[string]any); ok {
		if arr, hasArray := m[""]; hasArray {
			isArray = true
			if slice, ok := arr.([]any); ok {
				arrParams = slice
			} else if floatSlice, ok := arr.([]float64); ok {
				arrParams = make([]any, len(floatSlice))
				for i, v := range floatSlice {
					arrParams[i] = v
				}
			}
		} else {
			// Process named parameters
			namedParams = make(map[string]any, len(m))
			for k, v := range m {
				if len(k) > 0 && k[0] != ':' {
					namedParams[":"+k] = v
				} else {
					namedParams[k] = v
				}
			}
		}
	} else if slice, ok := params.([]any); ok {
		isArray = true
		arrParams = slice
	} else if floatSlice, ok := params.([]float64); ok {
		isArray = true
		arrParams = make([]any, len(floatSlice))
		for i, v := range floatSlice {
			arrParams[i] = v
		}
	}

	// Use positional params if explicitly provided
	if isPositional {
		arrParams = positionalParams
		isArray = true
	}

	// Limit positional params to actual placeholders
	if isArray && arrParams != nil {
		placeholderCount := strings.Count(query, "?")
		if len(arrParams) > placeholderCount {
			arrParams = arrParams[:placeholderCount]
		}
		execOpts.Args = arrParams
	} else if namedParams != nil {
		execOpts.Named = namedParams
	}

	return execOpts
}

// sqlOperation handles both query and exec operations
func sqlOperation(state *luajit.State, isQuery bool) int {
	operation := "query"
	if !isQuery {
		operation = "exec"
	}

	// Get database name
	if !state.IsString(1) {
		state.PushString(fmt.Sprintf("sqlite.%s: database name must be a string", operation))
		return -1
	}
	dbName := state.ToString(1)

	// Get query
	if !state.IsString(2) {
		state.PushString(fmt.Sprintf("sqlite.%s: query must be a string", operation))
		return -1
	}
	query := state.ToString(2)

	// Generate a temporary connection ID if needed
	defaultConnID := fmt.Sprintf("temp_%p", &query)

	// Process parameters and get connection ID
	params, connID, isPositional, positionalParams, err := processParams(state, defaultConnID)
	if err != nil {
		state.PushString(fmt.Sprintf("sqlite.%s: %s", operation, err.Error()))
		return -1
	}

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

	// For temporary connections, defer release
	if strings.HasPrefix(connID, "temp_") {
		defer func() {
			sqliteManager.mu.Lock()
			delete(sqliteManager.activeConns, connID)
			sqliteManager.mu.Unlock()
			pool.Put(conn)
		}()
	}

	// Prepare execution options
	execOpts := prepareExecOptions(query, params, isPositional, positionalParams)

	// Define rows slice outside the closure
	var rows []map[string]any

	// For queries, add result function
	if isQuery {
		execOpts.ResultFunc = func(stmt *sqlite.Stmt) error {
			row := make(map[string]any)
			columnCount := stmt.ColumnCount()

			for i := range columnCount {
				columnName := stmt.ColumnName(i)

				switch stmt.ColumnType(i) {
				case sqlite.TypeInteger:
					row[columnName] = stmt.ColumnInt64(i)
				case sqlite.TypeFloat:
					row[columnName] = stmt.ColumnFloat(i)
				case sqlite.TypeText:
					row[columnName] = stmt.ColumnText(i)
				case sqlite.TypeBlob:
					blobSize := stmt.ColumnLen(i)
					buf := make([]byte, blobSize)
					row[columnName] = stmt.ColumnBytes(i, buf)
				case sqlite.TypeNull:
					row[columnName] = nil
				}
			}

			// Add row copy to results
			rowCopy := make(map[string]any, len(row))
			maps.Copy(rowCopy, row)
			rows = append(rows, rowCopy)
			return nil
		}
	}

	// Execute query
	var execErr error
	if isQuery || execOpts.Args != nil || execOpts.Named != nil {
		execErr = sqlitex.Execute(conn, query, execOpts)
	} else {
		// Use ExecScript for queries without parameters
		execErr = sqlitex.ExecScript(conn, query)
	}

	if execErr != nil {
		state.PushString(fmt.Sprintf("sqlite.%s: %s", operation, execErr.Error()))
		return -1
	}

	// Return results for query, affected rows for exec
	if isQuery {
		// Create result table with rows
		state.NewTable()
		for i, row := range rows {
			state.PushNumber(float64(i + 1))
			if err := state.PushTable(row); err != nil {
				state.PushString(fmt.Sprintf("sqlite.%s: %s", operation, err.Error()))
				return -1
			}
			state.SetTable(-3)
		}
	} else {
		// Return number of affected rows
		state.PushNumber(float64(conn.Changes()))
	}

	return 1
}

// luaSQLQuery executes a SQL query and returns results to Lua
func luaSQLQuery(state *luajit.State) int {
	return sqlOperation(state, true)
}

// luaSQLExec executes a SQL statement without returning results
func luaSQLExec(state *luajit.State) int {
	return sqlOperation(state, false)
}

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