package runner

import (
	"context"
	"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"
)

// DbPools maintains database connection pools
var (
	dbPools = make(map[string]*sqlitex.Pool)
	poolsMu sync.RWMutex
	dataDir string
)

// InitSQLite initializes the SQLite subsystem
func InitSQLite(dir string) {
	dataDir = dir
	logger.Server("SQLite initialized with data directory: %s", dir)
}

// CleanupSQLite closes all database connections
func CleanupSQLite() {
	poolsMu.Lock()
	defer poolsMu.Unlock()

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

	dbPools = make(map[string]*sqlitex.Pool)
	logger.Debug("SQLite connections closed")
}

// getPool returns a connection pool for the database
func getPool(dbName string) (*sqlitex.Pool, error) {
	// Validate database name
	dbName = filepath.Base(dbName)
	if dbName == "" || dbName[0] == '.' {
		return nil, fmt.Errorf("invalid database name")
	}

	// Check for existing pool
	poolsMu.RLock()
	pool, exists := dbPools[dbName]
	if exists {
		poolsMu.RUnlock()
		return pool, nil
	}
	poolsMu.RUnlock()

	// Create new pool under write lock
	poolsMu.Lock()
	defer poolsMu.Unlock()

	// Double-check if a pool was created while waiting for lock
	if pool, exists = dbPools[dbName]; exists {
		return pool, nil
	}

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

	dbPools[dbName] = pool
	return pool, nil
}

// 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)

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

	// Get a connection from the pool
	conn, err := pool.Take(context.Background())
	if err != nil {
		state.PushString(fmt.Sprintf("sqlite.query: failed to get connection: %s", err.Error()))
		return -1
	}
	defer pool.Put(conn)

	// 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)

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

	// Get a connection from the pool
	conn, err := pool.Take(context.Background())
	if err != nil {
		state.PushString(fmt.Sprintf("sqlite.exec: failed to get connection: %s", err.Error()))
		return -1
	}
	defer pool.Put(conn)

	// 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)
}