package initialize

import (
	"fmt"
	"os"
	"path/filepath"

	"github.com/glebarez/sqlite"
	"go.uber.org/zap"
	"gorm.io/gorm"
	"wails-app/internal/config"
	"wails-app/internal/global"
	"wails-app/internal/initialize/internal"
)

// GormSqlite 初始化Sqlite数据库
func GormSqlite() *gorm.DB {
	s := global.GVA_CONFIG.Sqlite
	if s.Dbname == "" {
		return nil
	}

	// Resolve path: empty = %APPDATA%/smart-parking/
	if s.Path == "" {
		if appData := os.Getenv("APPDATA"); appData != "" {
			s.Path = appData
		} else {
			// Fallback: exe directory
			if exePath, err := os.Executable(); err == nil {
				s.Path = filepath.Dir(exePath)
			}
		}
		s.Path = filepath.Join(s.Path, "smart-parking")
	}

	// Ensure directory exists
	if err := os.MkdirAll(s.Path, 0755); err != nil {
		panic(fmt.Errorf("failed to create SQLite db directory %s: %w", s.Path, err))
	}

	dsn := filepath.Join(s.Path, s.Dbname+".db")
	fmt.Printf("SQLite database: %s\n", dsn)
	if global.GVA_LOG != nil {
		global.GVA_LOG.Info("SQLite 数据库路径", zap.String("dsn", dsn))
	}

	if db, err := gorm.Open(sqlite.Open(dsn), internal.Gorm.Config(s.Prefix, s.Singular)); err != nil {
		panic(err)
	} else {
		configureSQLite(db, s)
		return db
	}
}

// GormSqliteByConfig 初始化Sqlite数据库用过传入配置
func GormSqliteByConfig(s config.Sqlite) *gorm.DB {
	if s.Dbname == "" {
		return nil
	}

	if db, err := gorm.Open(sqlite.Open(s.Dsn()), internal.Gorm.Config(s.Prefix, s.Singular)); err != nil {
		panic(err)
	} else {
		configureSQLite(db, s)
		return db
	}
}

// configureSQLite limits concurrent connections and enables SQLite settings
// that avoid long writer starvation when device events and API requests share
// the same database file.
func configureSQLite(db *gorm.DB, s config.Sqlite) {
	sqlDB, err := db.DB()
	if err != nil {
		panic(err)
	}
	maxIdle := s.MaxIdleConns
	if maxIdle <= 0 {
		maxIdle = 1
	}
	maxOpen := s.MaxOpenConns
	if maxOpen <= 0 {
		maxOpen = 4
	}
	if maxOpen < maxIdle {
		maxOpen = maxIdle
	}
	sqlDB.SetMaxIdleConns(maxIdle)
	sqlDB.SetMaxOpenConns(maxOpen)

	// WAL allows readers to continue while a writer commits. busy_timeout
	// prevents transient lock contention from immediately failing a request.
	for _, pragma := range []string{
		"PRAGMA busy_timeout = 5000",
		"PRAGMA journal_mode = WAL",
		"PRAGMA synchronous = NORMAL",
	} {
		if err := sqlDB.Ping(); err != nil {
			if global.GVA_LOG != nil {
				global.GVA_LOG.Warn("SQLite 连接检查失败", zap.Error(err))
			}
			return
		}
		if _, err := sqlDB.Exec(pragma); err != nil && global.GVA_LOG != nil {
			global.GVA_LOG.Warn("SQLite PRAGMA 设置失败", zap.String("pragma", pragma), zap.Error(err))
		}
	}
}