package sqlite

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

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

	"Moonshark/logger"

	"git.sharkk.net/Go/Color"

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

var (
	dbPools     = make(map[string]*sqlitex.Pool)
	poolsMu     sync.RWMutex
	dataDir     string
	poolSize    = 8
	connTimeout = 5 * time.Second

	// Per-state connection cache
	stateConns   = make(map[string]*stateConn)
	stateConnsMu sync.RWMutex
)

// stateConn tracks a connection and its origin pool
type stateConn struct {
	conn *sqlite.Conn
	pool *sqlitex.Pool
}

func InitSQLite(dir string) {
	dataDir = dir
	logger.Infof("SQLite is g2g! %s", color.Yellow(dir))
}

func SetSQLitePoolSize(size int) {
	if size > 0 {
		poolSize = size
	}
}

func CleanupSQLite() {
	poolsMu.Lock()
	defer poolsMu.Unlock()

	// Return all cached connections to their pools
	stateConnsMu.Lock()
	for _, sc := range stateConns {
		if sc.pool != nil && sc.conn != nil {
			sc.pool.Put(sc.conn)
		}
	}
	stateConns = make(map[string]*stateConn)
	stateConnsMu.Unlock()

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

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

func getPool(dbName string) (*sqlitex.Pool, error) {
	dbName = filepath.Base(dbName)
	if dbName == "" || dbName[0] == '.' {
		return nil, fmt.Errorf("invalid database name")
	}

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

	poolsMu.Lock()
	defer poolsMu.Unlock()

	if pool, exists = dbPools[dbName]; exists {
		return pool, nil
	}

	dbPath := filepath.Join(dataDir, dbName+".db")
	pool, err := sqlitex.NewPool(dbPath, sqlitex.PoolOptions{
		PoolSize: poolSize,
		PrepareConn: func(conn *sqlite.Conn) error {
			pragmas := []string{
				"PRAGMA journal_mode = WAL",
				"PRAGMA synchronous = NORMAL",
				"PRAGMA cache_size = 1000",
				"PRAGMA foreign_keys = ON",
				"PRAGMA temp_store = MEMORY",
			}
			for _, pragma := range pragmas {
				if err := sqlitex.ExecuteTransient(conn, pragma, nil); err != nil {
					return err
				}
			}
			return nil
		},
	})
	if err != nil {
		return nil, fmt.Errorf("failed to open database: %w", err)
	}

	dbPools[dbName] = pool
	logger.Debugf("Created SQLite pool for %s (size: %d)", dbName, poolSize)
	return pool, nil
}

// getStateConnection gets or creates a reusable connection for the state+db
func getStateConnection(stateIndex int, dbName string) (*sqlite.Conn, error) {
	connKey := fmt.Sprintf("%d-%s", stateIndex, dbName)

	stateConnsMu.RLock()
	sc, exists := stateConns[connKey]
	stateConnsMu.RUnlock()

	if exists && sc.conn != nil {
		return sc.conn, nil
	}

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

	ctx, cancel := context.WithTimeout(context.Background(), connTimeout)
	defer cancel()

	conn, err := pool.Take(ctx)
	if err != nil {
		return nil, fmt.Errorf("connection timeout: %w", err)
	}

	// Cache it with pool reference
	stateConnsMu.Lock()
	stateConns[connKey] = &stateConn{
		conn: conn,
		pool: pool,
	}
	stateConnsMu.Unlock()

	return conn, nil
}

func sqlQuery(state *luajit.State) int {
	if err := state.CheckMinArgs(3); err != nil {
		return state.PushError("sqlite.query: %v", err)
	}

	dbName, err := state.SafeToString(1)
	if err != nil {
		return state.PushError("sqlite.query: database name must be string")
	}

	query, err := state.SafeToString(2)
	if err != nil {
		return state.PushError("sqlite.query: query must be string")
	}

	stateIndex := int(state.ToNumber(-1))

	conn, err := getStateConnection(stateIndex, dbName)
	if err != nil {
		return state.PushError("sqlite.query: %v", err)
	}

	var execOpts sqlitex.ExecOptions
	rows := make([]any, 0, 16)

	if state.GetTop() >= 4 && !state.IsNil(3) {
		if err := setupParams(state, 3, &execOpts); err != nil {
			return state.PushError("sqlite.query: %v", err)
		}
	}

	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)
				if blobSize > 0 {
					buf := make([]byte, blobSize)
					row[colName] = stmt.ColumnBytes(i, buf)
				} else {
					row[colName] = []byte{}
				}
			case sqlite.TypeNull:
				row[colName] = nil
			}
		}
		rows = append(rows, row)
		return nil
	}

	if err := sqlitex.Execute(conn, query, &execOpts); err != nil {
		return state.PushError("sqlite.query: %v", err)
	}

	if err := state.PushValue(rows); err != nil {
		return state.PushError("sqlite.query: %v", err)
	}

	return 1
}

func sqlExec(state *luajit.State) int {
	if err := state.CheckMinArgs(3); err != nil {
		return state.PushError("sqlite.exec: %v", err)
	}

	dbName, err := state.SafeToString(1)
	if err != nil {
		return state.PushError("sqlite.exec: database name must be string")
	}

	query, err := state.SafeToString(2)
	if err != nil {
		return state.PushError("sqlite.exec: query must be string")
	}

	stateIndex := int(state.ToNumber(-1))

	conn, err := getStateConnection(stateIndex, dbName)
	if err != nil {
		return state.PushError("sqlite.exec: %v", err)
	}

	hasParams := state.GetTop() >= 4 && !state.IsNil(3)

	if strings.Contains(query, ";") && !hasParams {
		if err := sqlitex.ExecScript(conn, query); err != nil {
			return state.PushError("sqlite.exec: %v", err)
		}
		state.PushNumber(float64(conn.Changes()))
		return 1
	}

	if !hasParams {
		if err := sqlitex.Execute(conn, query, nil); err != nil {
			return state.PushError("sqlite.exec: %v", err)
		}
		state.PushNumber(float64(conn.Changes()))
		return 1
	}

	var execOpts sqlitex.ExecOptions
	if err := setupParams(state, 3, &execOpts); err != nil {
		return state.PushError("sqlite.exec: %v", err)
	}

	if err := sqlitex.Execute(conn, query, &execOpts); err != nil {
		return state.PushError("sqlite.exec: %v", err)
	}

	state.PushNumber(float64(conn.Changes()))
	return 1
}

func setupParams(state *luajit.State, paramIndex int, execOpts *sqlitex.ExecOptions) error {
	if state.IsTable(paramIndex) {
		paramsAny, err := state.ToTable(paramIndex)
		if err != nil {
			return fmt.Errorf("invalid parameters: %w", err)
		}

		// Handle direct array types
		if arrParams, ok := paramsAny.([]any); ok {
			execOpts.Args = arrParams
			return nil
		}
		if strArr, ok := paramsAny.([]string); ok {
			args := make([]any, len(strArr))
			for i, v := range strArr {
				args[i] = v
			}
			execOpts.Args = args
			return nil
		}
		if floatArr, ok := paramsAny.([]float64); ok {
			args := make([]any, len(floatArr))
			for i, v := range floatArr {
				args[i] = v
			}
			execOpts.Args = args
			return nil
		}

		params, ok := paramsAny.(map[string]any)
		if !ok {
			return fmt.Errorf("unsupported parameter type: %T", paramsAny)
		}

		// Check for array-style parameters (empty string key indicates array)
		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 {
		// Multiple individual parameters
		count := state.GetTop() - 2
		args := make([]any, count)
		for i := range count {
			idx := i + 3
			val, err := state.ToValue(idx)
			if err != nil {
				return fmt.Errorf("invalid parameter %d: %w", i+1, err)
			}
			args[i] = val
		}
		execOpts.Args = args
	}

	return nil
}

func sqlGetOne(state *luajit.State) int {
	if err := state.CheckMinArgs(3); err != nil {
		return state.PushError("sqlite.get_one: %v", err)
	}

	dbName, err := state.SafeToString(1)
	if err != nil {
		return state.PushError("sqlite.get_one: database name must be string")
	}

	query, err := state.SafeToString(2)
	if err != nil {
		return state.PushError("sqlite.get_one: query must be string")
	}

	stateIndex := int(state.ToNumber(-1))

	conn, err := getStateConnection(stateIndex, dbName)
	if err != nil {
		return state.PushError("sqlite.get_one: %v", err)
	}

	var execOpts sqlitex.ExecOptions
	var result map[string]any

	// Check if params provided (before state index)
	if state.GetTop() >= 4 && !state.IsNil(3) {
		if err := setupParams(state, 3, &execOpts); err != nil {
			return state.PushError("sqlite.get_one: %v", err)
		}
	}

	execOpts.ResultFunc = func(stmt *sqlite.Stmt) error {
		if result != nil {
			return nil
		}

		result = make(map[string]any)
		colCount := stmt.ColumnCount()

		for i := range colCount {
			colName := stmt.ColumnName(i)
			switch stmt.ColumnType(i) {
			case sqlite.TypeInteger:
				result[colName] = stmt.ColumnInt64(i)
			case sqlite.TypeFloat:
				result[colName] = stmt.ColumnFloat(i)
			case sqlite.TypeText:
				result[colName] = stmt.ColumnText(i)
			case sqlite.TypeBlob:
				blobSize := stmt.ColumnLen(i)
				if blobSize > 0 {
					buf := make([]byte, blobSize)
					result[colName] = stmt.ColumnBytes(i, buf)
				} else {
					result[colName] = []byte{}
				}
			case sqlite.TypeNull:
				result[colName] = nil
			}
		}
		return nil
	}

	if err := sqlitex.Execute(conn, query, &execOpts); err != nil {
		return state.PushError("sqlite.get_one: %v", err)
	}

	if result == nil {
		state.PushNil()
	} else {
		if err := state.PushValue(result); err != nil {
			return state.PushError("sqlite.get_one: %v", err)
		}
	}

	return 1
}

// CleanupStateConnection releases all connections for a specific state
func CleanupStateConnection(stateIndex int) {
	stateConnsMu.Lock()
	defer stateConnsMu.Unlock()

	statePrefix := fmt.Sprintf("%d-", stateIndex)

	for key, sc := range stateConns {
		if strings.HasPrefix(key, statePrefix) {
			if sc.pool != nil && sc.conn != nil {
				sc.pool.Put(sc.conn)
			}
			delete(stateConns, key)
		}
	}
}

func RegisterSQLiteFunctions(state *luajit.State) error {
	if err := state.RegisterGoFunction("__sqlite_query", sqlQuery); err != nil {
		return err
	}
	if err := state.RegisterGoFunction("__sqlite_exec", sqlExec); err != nil {
		return err
	}
	if err := state.RegisterGoFunction("__sqlite_get_one", sqlGetOne); err != nil {
		return err
	}
	return nil
}