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

import (
	"embed"
	"html/template"
	"log"
	"net/http"

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

//go:embed html/*.html
var templateFS embed.FS

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

// Handler serves template-rendered pages.
type Handler struct {
	db        *database.DB
	cfg       *config.Config
	templates map[string]*template.Template
}

// NewHandler creates a new templates handler and parses embedded templates.
func NewHandler(db *database.DB, cfg *config.Config) *Handler {
	h := &Handler{db: db, cfg: cfg, templates: make(map[string]*template.Template)}
	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)
	mux.HandleFunc("GET /profile", h.profilePage)
}

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

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

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

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

func (h *Handler) profilePage(w http.ResponseWriter, r *http.Request) {
	h.render(w, "profile.html", pageData{Title: "Профиль"})
}

// render executes the "base.html" template which {{template "content" .}}
// pulls in the per-page content block.
func (h *Handler) render(w http.ResponseWriter, page string, data pageData) {
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	tmpl, ok := h.templates[page]
	if !ok {
		log.Printf("Template not found: %s", page)
		http.Error(w, "Template not found", http.StatusInternalServerError)
		return
	}
	if err := tmpl.ExecuteTemplate(w, "base.html", data); err != nil {
		log.Printf("Template error (%s): %v", page, err)
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
	}
}

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

// parseTemplates parses each page template individually by combining the base
// layout with the specific page content. This avoids the issue where
// multiple {{define "content"}} blocks in wildcard-parsed files overwrite
// each other (last alphabetically wins).
func (h *Handler) parseTemplates() {
	pages := []string{"index.html", "login.html", "register.html", "profile.html"}
	for _, page := range pages {
		tmpl, err := template.New("base.html").Funcs(template.FuncMap{}).ParseFS(templateFS, "html/base.html", "html/"+page)
		if err != nil {
			log.Printf("Template parse error (%s): %v", page, err)
			continue
		}
		h.templates[page] = tmpl
		log.Printf("Loaded template: %s", page)
	}
}