package config

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

	"gopkg.in/ini.v1"
)

// Config 应用全局配置
type Config struct {
	WorkPath  string
	Port      int
	DataDir   string
	JWTSecret string
	DBDSN     string
	DevMode   bool
}

// Parse 解析配置：环境变量 > app.ini > 默认值
func Parse() (*Config, error) {
	workPath, err := os.Getwd()
	if err != nil {
		return nil, fmt.Errorf("获取工作目录失败: %w", err)
	}

	// 默认值
	cfg := &Config{
		WorkPath: workPath,
		Port:     3001,
		DataDir:  filepath.Join(workPath, "data"),
		DBDSN:    "postgres://postgres:postgres@localhost:5432/jiang13?sslmode=disable",
		DevMode:  true,
	}

	// 尝试加载 app.ini
	iniPath := filepath.Join(workPath, "app.ini")
	if _, err := os.Stat(iniPath); err == nil {
		f, err := ini.Load(iniPath)
		if err != nil {
			return nil, fmt.Errorf("加载 app.ini 失败: %w", err)
		}
		if s := f.Section("server"); s.HasKey("HTTP_PORT") {
			if v, err := s.Key("HTTP_PORT").Int(); err == nil {
				cfg.Port = v
			}
		}
		if s := f.Section("database"); s.HasKey("DSN") {
			cfg.DBDSN = s.Key("DSN").String()
		}
		if s := f.Section("security"); s.HasKey("JWT_SECRET") {
			cfg.JWTSecret = s.Key("JWT_SECRET").String()
		}
		if s := f.Section("paths"); s.HasKey("DATA") {
			dataRel := s.Key("DATA").String()
			if !filepath.IsAbs(dataRel) {
				cfg.DataDir = filepath.Join(workPath, dataRel)
			} else {
				cfg.DataDir = dataRel
			}
		}
		if s := f.Section("app"); s.HasKey("DEV_MODE") {
			cfg.DevMode = s.Key("DEV_MODE").MustBool(true)
		}
	}

	// 环境变量覆盖
	if v := os.Getenv("HTTP_PORT"); v != "" {
		if p, err := strconv.Atoi(v); err == nil {
			cfg.Port = p
		}
	}
	if v := os.Getenv("DB_DSN"); v != "" {
		cfg.DBDSN = v
	}
	if v := os.Getenv("JWT_SECRET"); v != "" {
		cfg.JWTSecret = v
	}
	if v := os.Getenv("DEV_MODE"); v != "" {
		cfg.DevMode = strings.EqualFold(v, "true") || v == "1"
	}

	// 确保数据目录存在
	if err := os.MkdirAll(cfg.DataDir, 0755); err != nil {
		return nil, fmt.Errorf("创建数据目录失败: %w", err)
	}

	// JWT 密钥：留空则自动生成并持久化
	if strings.TrimSpace(cfg.JWTSecret) == "" {
		secretFile := filepath.Join(cfg.DataDir, ".jwt_secret")
		if data, err := os.ReadFile(secretFile); err == nil && len(data) > 0 {
			cfg.JWTSecret = string(data)
		} else {
			cfg.JWTSecret = generateSecret(32)
			_ = os.WriteFile(secretFile, []byte(cfg.JWTSecret), 0600)
		}
	}

	return cfg, nil
}

func generateSecret(n int) string {
	const chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	b := make([]byte, n)
	for i := range b {
		b[i] = chars[i%len(chars)]
	}
	return string(b)
}