package config

import (
	"log/slog"
	"os"
	"path/filepath"
	"strings"
)

type Config struct {
	Port              string
	DataDir           string
	DatabasePath      string
	JWTSecret         string
	BaseURL           string
	AllowRegistration bool
	LogLevel          string
	Debug             bool
	DemoMode          bool

	// Optional SMTP environment variables (can also be overridden/configured in DB system_settings)
	SMTPHost string
	SMTPPort string
	SMTPUser string
	SMTPPass string
	SMTPFrom string
	SMTPTLS  bool
	// SMTPSkipVerify accepts self-signed or mismatching certificates (internal mail servers)
	SMTPSkipVerify bool

	// Legal notices (Impressum, Datenschutz): an external URL and/or Markdown text, shown even before login
	Legal LegalTexts
}

type LegalTexts struct {
	ImprintURL, ImprintContent string
	PrivacyURL, PrivacyContent string
}

// legalContent reads Markdown from NAME or, for longer texts, from the file named in NAME_FILE.
func legalContent(name string) string {
	if v := strings.TrimSpace(os.Getenv(name)); v != "" {
		return v
	}
	if path := strings.TrimSpace(os.Getenv(name + "_FILE")); path != "" {
		data, err := os.ReadFile(path)
		if err != nil {
			slog.Warn("Rechtstext konnte nicht gelesen werden", "variable", name+"_FILE", "error", err)
			return ""
		}
		return strings.TrimSpace(string(data))
	}
	return ""
}

// legalURL accepts only http(s) links, so a misconfiguration cannot inject javascript: URLs.
func legalURL(name string) string {
	v := strings.TrimSpace(os.Getenv(name))
	if v == "" {
		return ""
	}
	if !strings.HasPrefix(v, "https://") && !strings.HasPrefix(v, "http://") {
		slog.Warn("Rechtstext-URL ignoriert: nur http(s) erlaubt", "variable", name)
		return ""
	}
	return v
}

func Load() *Config {
	port := getEnv("PORT", "8080")
	dataDir := getEnv("DATA_DIR", "./data")
	dbURL := getEnv("DATABASE_URL", "")

	dbPath := filepath.Join(dataDir, "mindsift.db")
	if strings.HasPrefix(dbURL, "sqlite://") {
		dbPath = strings.TrimPrefix(dbURL, "sqlite://")
	} else if dbURL != "" && !strings.HasPrefix(dbURL, "postgres") {
		dbPath = dbURL
	}

	jwtSecret := getEnv("JWT_SECRET", "mindsift-default-selfhosted-jwt-secret-key-2026")
	baseURL := getEnv("BASE_URL", "http://localhost:"+port)
	allowReg := strings.ToLower(getEnv("ALLOW_REGISTRATION", "false")) == "true"

	debugVal := strings.ToLower(getEnv("DEBUG", "false"))
	debug := debugVal == "true" || debugVal == "1" || debugVal == "yes" || debugVal == "on"

	logLevel := strings.ToLower(getEnv("LOG_LEVEL", "info"))
	if debug {
		logLevel = "debug"
	}

	demoVal := strings.ToLower(getEnv("MINDA_DEMO", getEnv("MINDSIFT_DEMO", getEnv("DEMO_MODE", "false"))))
	demoMode := demoVal == "true" || demoVal == "1" || demoVal == "yes" || demoVal == "on"

	smtpHost := getEnv("SMTP_HOST", "")
	smtpPort := getEnv("SMTP_PORT", "587")
	smtpUser := getEnv("SMTP_USER", "")
	smtpPass := getEnv("SMTP_PASS", "")
	smtpFrom := getEnv("SMTP_FROM", "")
	smtpTLS := strings.ToLower(getEnv("SMTP_TLS", "true")) != "false"
	smtpSkipVerify := strings.ToLower(getEnv("SMTP_SKIP_VERIFY", "false")) == "true"

	return &Config{
		Port:              port,
		DataDir:           dataDir,
		DatabasePath:      dbPath,
		JWTSecret:         jwtSecret,
		BaseURL:           baseURL,
		AllowRegistration: allowReg,
		LogLevel:          logLevel,
		Debug:             debug,
		DemoMode:          demoMode,
		SMTPHost:          smtpHost,
		SMTPPort:          smtpPort,
		SMTPUser:          smtpUser,
		SMTPPass:          smtpPass,
		SMTPFrom:          smtpFrom,
		SMTPTLS:           smtpTLS,
		SMTPSkipVerify:    smtpSkipVerify,
		Legal: LegalTexts{
			ImprintURL:     legalURL("LEGAL_IMPRINT_URL"),
			ImprintContent: legalContent("LEGAL_IMPRINT_CONTENT"),
			PrivacyURL:     legalURL("LEGAL_PRIVACY_URL"),
			PrivacyContent: legalContent("LEGAL_PRIVACY_CONTENT"),
		},
	}
}

// SlogLevel parses Config.LogLevel into a standard slog.Level.
func (c *Config) SlogLevel() slog.Level {
	switch strings.ToLower(strings.TrimSpace(c.LogLevel)) {
	case "debug":
		return slog.LevelDebug
	case "warn", "warning":
		return slog.LevelWarn
	case "error":
		return slog.LevelError
	default:
		return slog.LevelInfo
	}
}

func getEnv(key, fallback string) string {
	if val, ok := os.LookupEnv(key); ok && strings.TrimSpace(val) != "" {
		return strings.TrimSpace(val)
	}
	return fallback
}