// package templates handles Go html/template rendering for the website.
package templates

import (
	"html/template"
	"log"
	"net/http"
	"os"
	"path/filepath"

	"gitea.mrixs.me/Mrixs/MrixsCraft-server/internal/config"
	"gitea.mrixs.me/Mrixs/MrixsCraft-server/internal/database"
)

// pageData is passed to all templates.
type pageData struct {
	Title string
}

// Handler serves template-rendered pages.
type Handler struct {
	db     *database.DB
	cfg    *config.Config
	tmpl   *template.Template
	loaded bool
}

// NewHandler creates a new templates handler and parses on-disk templates.
func NewHandler(db *database.DB, cfg *config.Config) *Handler {
	h := &Handler{db: db, cfg: cfg}
	h.parseTemplates()
	return h
}

// RegisterRoutes mounts template-rendered pages.
func (h *Handler) RegisterRoutes(mux *http.ServeMux) {
	mux.HandleFunc("GET /", h.index)
	mux.HandleFunc("GET /login", h.loginPage)
	mux.HandleFunc("GET /register", h.registerPage)
}

// ── Page handlers ──────────────────────────────────────────────

func (h *Handler) index(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		http.NotFound(w, r)
		return
	}
	if !h.loaded {
		fallback(w, "MrixsCraft")
		return
	}
	h.render(w, "index.html", pageData{Title: "Главная"})
}

func (h *Handler) loginPage(w http.ResponseWriter, r *http.Request) {
	if !h.loaded {
		fallback(w, "Login")
		return
	}
	h.render(w, "login.html", pageData{Title: "Вход"})
}

func (h *Handler) registerPage(w http.ResponseWriter, r *http.Request) {
	if !h.loaded {
		fallback(w, "Register")
		return
	}
	h.render(w, "register.html", pageData{Title: "Регистрация"})
}

// render executes the named template with data, writing to w.
func (h *Handler) render(w http.ResponseWriter, name string, data pageData) {
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	if err := h.tmpl.ExecuteTemplate(w, name, data); err != nil {
		log.Printf("Template error (%s): %v", name, err)
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
	}
}

// fallback writes a minimal placeholder when templates are missing.
func fallback(w http.ResponseWriter, title string) {
	w.WriteHeader(http.StatusOK)
	w.Write([]byte("<h1>" + title + "</h1>"))
}

// ── Template parsing ───────────────────────────────────────────

func (h *Handler) parseTemplates() {
	dirs := []string{
		filepath.Join("internal", "templates", "html"),
		"templates",
	}
	for _, dir := range dirs {
		if _, err := os.Stat(dir); err != nil {
			continue
		}
		pattern := filepath.Join(dir, "*.html")
		tmpl, err := template.New("").Funcs(template.FuncMap{}).ParseGlob(pattern)
		if err != nil {
			log.Printf("Template parse error in %s: %v", dir, err)
			continue
		}
		if tmpl != nil {
			h.tmpl = tmpl
			h.loaded = true
			log.Printf("Loaded templates from %s", dir)
			return
		}
	}
	log.Println("No HTML templates found; using placeholder responses")
}