package main

import (
	"bufio"
	"crypto/sha256"
	"encoding/hex"
	"html/template"
	"log"
	"os"
	"path/filepath"
	"strings"

	"github.com/gofiber/fiber/v3"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"prada.ch/controllers"
)

type landingData struct {
	Brand        string
	InitialTitle string
	FooterText   string
	AssetVersion string
}

type resetPasswordPageData struct {
	Token string
}

func main() {
	loadDotEnv(".env")

	db, err := initDB("data/subscribers.db")
	if err != nil {
		log.Fatal(err)
	}
	sqlDB, err := db.DB()
	if err != nil {
		log.Fatal(err)
	}
	defer sqlDB.Close()

	h := &controller{
		db:                     db,
		mailConfig:             getSMTPConfigFromEnv(),
		landingTemplate:        template.Must(template.ParseFiles("templates/public/index.html")),
		howToWorkTemplate:      template.Must(template.ParseFiles("templates/public/howtowork.html")),
		loginTemplate:          template.Must(template.ParseFiles("templates/public/login.html")),
		signupTemplate:         template.Must(template.ParseFiles("templates/public/signup.html")),
		forgotPasswordTemplate: template.Must(template.ParseFiles("templates/public/forgot_password.html")),
		resetPasswordTemplate:  template.Must(template.ParseFiles("templates/public/reset_password.html")),
		welcomeTemplate:        template.Must(template.ParseFiles("templates/private/welcome.html")),
		assetVersion:           buildAssetVersion("static/css/main.css", "static/js/i18n.js"),
	}
	h.subscribeController = &controllers.SubscribeController{
		DB:                 h.db,
		IsUniqueConstraint: isUniqueConstraint,
	}
	h.authController = &controllers.AuthController{
		DB:                 h.db,
		IsUniqueConstraint: isUniqueConstraint,
		AppBaseURL:         getAppBaseURL,
		MailConfigured:     h.mailConfig.isConfigured,
		SendPasswordResetEmail: func(recipientEmail, resetURL string) error {
			return sendPasswordResetEmail(h.mailConfig, recipientEmail, resetURL)
		},
		SendEmailVerificationMail: func(recipientEmail, verifyURL string) error {
			return sendEmailVerificationEmail(h.mailConfig, recipientEmail, verifyURL)
		},
	}

	app := fiber.New()
	app.Get("/static/*", h.staticFile)
	app.Post("/api/subscribe", h.subscribeController.Subscribe)
	app.Post("/api/auth/register", h.authController.Register)
	app.Post("/api/auth/login", h.authController.Login)
	app.Post("/api/auth/logout", h.authController.Logout)
	app.Get("/api/auth/me", h.authController.Me)
	app.Post("/api/auth/forgot-password", h.authController.ForgotPassword)
	app.Post("/api/auth/resend-verification", h.authController.ResendVerification)
	app.Post("/api/auth/reset-password", h.authController.ResetPassword)
	app.Get("/auth/verify-email", h.authController.VerifyEmail)
	app.Get("/", h.home)
	app.Get("/reset-password", h.resetPasswordPage)
	app.Get("/howtowork", h.howToWorkPage)
	app.Get("/login", h.loginPage)
	app.Get("/signup", h.signupPage)
	app.Get("/forgot-password", h.forgotPasswordPage)
	app.Get("/welcome", h.welcomePage)

	log.Fatal(app.Listen(":6082$"))
}

func buildAssetVersion(paths ...string) string {
	hasher := sha256.New()
	for _, path := range paths {
		content, err := os.ReadFile(path)
		if err != nil {
			log.Printf("asset version fallback, unable to read %s: %v", path, err)
			return "dev"
		}
		hasher.Write(content)
	}
	return hex.EncodeToString(hasher.Sum(nil))[:12]
}

func initDB(path string) (*gorm.DB, error) {
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		return nil, err
	}

	db, err := gorm.Open(sqlite.Open(path), &gorm.Config{})
	if err != nil {
		return nil, err
	}

	if err := db.Exec("PRAGMA foreign_keys = ON;").Error; err != nil {
		return nil, err
	}

	models := []any{
		&Subscriber{},
		&User{},
		&Session{},
		&PasswordResetToken{},
		&EmailVerificationToken{},
	}
	for _, model := range models {
		if db.Migrator().HasTable(model) {
			continue
		}
		if err := db.AutoMigrate(model); err != nil {
			return nil, err
		}
	}

	return db, nil
}

func isUniqueConstraint(err error) bool {
	if err == nil {
		return false
	}
	return strings.Contains(strings.ToLower(err.Error()), "unique")
}

func loadDotEnv(path string) {
	file, err := os.Open(path)
	if err != nil {
		return
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		parts := strings.SplitN(line, "=", 2)
		if len(parts) != 2 {
			continue
		}
		key := strings.TrimSpace(parts[0])
		value := strings.TrimSpace(parts[1])
		if key == "" {
			continue
		}
		if _, exists := os.LookupEnv(key); !exists {
			os.Setenv(key, value)
		}
	}
}