package app

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

type Config struct {
	Addr                          string
	DBPath                        string
	DataDir                       string
	CookieName                    string
	SessionTTLHours               int
	AdminEmail                    string
	AdminPassword                 string
	PublicHostname                string
	PublicBaseURL                 string
	SMTPHost                      string
	SMTPPort                      string
	SMTPUsername                  string
	SMTPPassword                  string
	SMTPRequireTLS                bool
	SubmissionAddr                string
	SubmissionTLSAddr             string
	SubmissionMaxMessageMB        int
	TLSCertFile                   string
	TLSKeyFile                    string
	MaildirRoot                   string
	MaildirScanSeconds            int
	AllowInsecureHTTP             bool
	OpenRegistration              bool
	TwoFactorEnabled              bool
	TurnstileEnabled              bool
	TurnstileSiteKey              string
	TurnstileSecretKey            string
	CatchAllEnabled               bool
	MailAutoRefresh               bool
	MailRefreshSeconds            int
	UserMailboxApplyEnabled       bool
	UserMailboxDomainIDs          string
	ReservedMailboxPrefixes       string
	ExternalIMAPSecretKey         string
	ExternalIMAPSyncSeconds       int
	ExternalIMAPAllowPrivateHosts bool
}

func LoadConfig() Config {
	dataDir := getenv("LANQIN_DATA_DIR", "./data")
	return Config{
		Addr:                          getenv("LANQIN_ADDR", ":8080"),
		DBPath:                        getenv("LANQIN_DB_PATH", filepath.Join(dataDir, "lanqin.db")),
		DataDir:                       dataDir,
		CookieName:                    getenv("LANQIN_COOKIE_NAME", "lanqin_session"),
		SessionTTLHours:               getenvInt("LANQIN_SESSION_TTL_HOURS", 24*7),
		AdminEmail:                    strings.ToLower(getenv("LANQIN_ADMIN_EMAIL", "admin@lanqin.local")),
		AdminPassword:                 getenv("LANQIN_ADMIN_PASSWORD", ""),
		PublicHostname:                getenv("LANQIN_PUBLIC_HOSTNAME", "mail.lanqin.local"),
		PublicBaseURL:                 getenv("LANQIN_PUBLIC_BASE_URL", "http://localhost:5173"),
		SMTPHost:                      getenv("LANQIN_SMTP_HOST", ""),
		SMTPPort:                      getenv("LANQIN_SMTP_PORT", "25"),
		SMTPUsername:                  getenv("LANQIN_SMTP_USERNAME", ""),
		SMTPPassword:                  getenv("LANQIN_SMTP_PASSWORD", ""),
		SMTPRequireTLS:                getenvBool("LANQIN_SMTP_REQUIRE_TLS", false),
		SubmissionAddr:                getenv("LANQIN_SUBMISSION_ADDR", ""),
		SubmissionTLSAddr:             getenv("LANQIN_SUBMISSION_TLS_ADDR", ""),
		SubmissionMaxMessageMB:        getenvInt("LANQIN_SUBMISSION_MAX_MESSAGE_MB", 35),
		TLSCertFile:                   getenv("LANQIN_TLS_CERT_FILE", ""),
		TLSKeyFile:                    getenv("LANQIN_TLS_KEY_FILE", ""),
		MaildirRoot:                   getenv("LANQIN_MAILDIR_ROOT", ""),
		MaildirScanSeconds:            getenvInt("LANQIN_MAILDIR_SCAN_SECONDS", 30),
		AllowInsecureHTTP:             getenvBool("LANQIN_ALLOW_INSECURE_HTTP", true),
		OpenRegistration:              getenvBool("LANQIN_OPEN_REGISTRATION", false),
		TwoFactorEnabled:              getenvBool("LANQIN_TWO_FACTOR_ENABLED", false),
		TurnstileEnabled:              getenvBool("LANQIN_TURNSTILE_ENABLED", false),
		TurnstileSiteKey:              getenv("LANQIN_TURNSTILE_SITE_KEY", ""),
		TurnstileSecretKey:            getenv("LANQIN_TURNSTILE_SECRET_KEY", ""),
		CatchAllEnabled:               getenvBool("LANQIN_CATCH_ALL_ENABLED", false),
		MailAutoRefresh:               getenvBool("LANQIN_MAIL_AUTO_REFRESH", true),
		MailRefreshSeconds:            getenvInt("LANQIN_MAIL_REFRESH_SECONDS", 30),
		UserMailboxApplyEnabled:       getenvBool("LANQIN_USER_MAILBOX_APPLY_ENABLED", false),
		UserMailboxDomainIDs:          getenv("LANQIN_USER_MAILBOX_DOMAIN_IDS", ""),
		ReservedMailboxPrefixes:       getenv("LANQIN_RESERVED_MAILBOX_PREFIXES", "admin,postmaster,abuse,hostmaster,webmaster,root,security,noreply,no-reply,mailer-daemon"),
		ExternalIMAPSecretKey:         getenv("LANQIN_EXTERNAL_IMAP_SECRET_KEY", ""),
		ExternalIMAPSyncSeconds:       getenvInt("LANQIN_EXTERNAL_IMAP_SYNC_SECONDS", 300),
		ExternalIMAPAllowPrivateHosts: getenvBool("LANQIN_EXTERNAL_IMAP_ALLOW_PRIVATE_HOSTS", false),
	}
}

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

func getenvBool(key string, fallback bool) bool {
	v := strings.ToLower(strings.TrimSpace(os.Getenv(key)))
	if v == "" {
		return fallback
	}
	return v == "1" || v == "true" || v == "yes" || v == "on"
}

func getenvInt(key string, fallback int) int {
	v := strings.TrimSpace(os.Getenv(key))
	if v == "" {
		return fallback
	}
	var n int
	_, err := fmt.Sscanf(v, "%d", &n)
	if err != nil || n <= 0 {
		return fallback
	}
	return n
}