package config

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

type Config struct {
	Port        string
	DatabaseURL string
	CORSOrigins []string

	// 首次启动时创建的默认管理员
	AdminUser     string
	AdminPassword string

	// Cookie 是否要求 HTTPS（生产环境置 true）
	SecureCookie bool
	CookieName   string

	// 附件：文件内容存盘，默认与 SQLite 同目录下的 attachments/
	AttachmentDir string
	// 单个附件上限（字节）。默认 25MB，与常见邮箱附件限额一致
	MaxAttachmentBytes int64
	// MaxAppearanceBytes 是壁纸图片上限（客户端会先压到 ~2.4MB，这里是兜底）。
	MaxAppearanceBytes int64
}

var C *Config

func Load() *Config {
	C = &Config{
		Port: getEnv("PORT", "8180"),
		// 空值 = 用内置 SQLite（data/agentmail.db，可用 AGENTMAIL_DATA_DIR 改目录）。
		// 想接外部库就给 postgres://…；也接受 sqlite:///path/x.db 与裸路径。
		DatabaseURL: getEnv("DATABASE_URL", ""),
		CORSOrigins: splitEnv("CORS_ORIGINS", []string{
			"http://localhost:5173",
			"http://127.0.0.1:5173",
		}),
		AdminUser:     strings.ToLower(getEnv("ADMIN_USER", "admin")),
		AdminPassword: getEnv("ADMIN_PASSWORD", ""),
		SecureCookie:  getEnvBool("SECURE_COOKIE", false),
		CookieName:    getEnv("COOKIE_NAME", "am_session"),

		AttachmentDir: getEnv("AGENTMAIL_ATTACHMENT_DIR",
			filepath.Join(getEnv("AGENTMAIL_DATA_DIR", "data"), "attachments")),
		MaxAttachmentBytes: getEnvInt64("AGENTMAIL_MAX_ATTACHMENT_BYTES", 25<<20),
		MaxAppearanceBytes: getEnvInt64("AGENTMAIL_MAX_APPEARANCE_BYTES", 4<<20),
	}
	return C
}

func getEnv(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}

func getEnvBool(key string, fallback bool) bool {
	if v := os.Getenv(key); v != "" {
		if b, err := strconv.ParseBool(v); err == nil {
			return b
		}
	}
	return fallback
}

func getEnvInt64(key string, fallback int64) int64 {
	if v := os.Getenv(key); v != "" {
		if n, err := strconv.ParseInt(v, 10, 64); err == nil && n > 0 {
			return n
		}
	}
	return fallback
}

func splitEnv(key string, fallback []string) []string {
	v := os.Getenv(key)
	if v == "" {
		return fallback
	}
	parts := strings.Split(v, ",")
	out := make([]string, 0, len(parts))
	for _, p := range parts {
		if s := strings.TrimSpace(p); s != "" {
			out = append(out, s)
		}
	}
	if len(out) == 0 {
		return fallback
	}
	return out
}