package handlers

import (
	"html/template"
	"io/fs"
	"net/http"
	"path/filepath"
	"strings"

	"github.com/jackc/pgx/v5/pgxpool"
	"vpn-panel/internal/config"
	"vpn-panel/internal/store"
	"vpn-panel/web"
)

type Handler struct {
	cfg      *config.Config
	pool     *pgxpool.Pool
	users    *store.UserStore
	tmpl     map[string]*template.Template
	secret   string
	domain   string
}

func New(cfg *config.Config, pool *pgxpool.Pool) (*Handler, error) {
	tmpl, err := loadTemplates()
	if err != nil {
		return nil, err
	}
	return &Handler{
		cfg:    cfg,
		pool:   pool,
		users:  store.NewUserStore(pool),
		tmpl:   tmpl,
		secret: cfg.SecretKey,
		domain: cfg.AppDomain,
	}, nil
}

func loadTemplates() (map[string]*template.Template, error) {
	funcs := template.FuncMap{
		"eq": func(a, b any) bool { return a == b },
	}
	out := make(map[string]*template.Template)

	err := fs.WalkDir(web.Templates, "templates", func(path string, d fs.DirEntry, err error) error {
		if err != nil || d.IsDir() || !strings.HasSuffix(path, ".html") {
			return err
		}
		name := strings.TrimSuffix(filepath.Base(path), ".html")
		content, err := web.Templates.ReadFile(path)
		if err != nil {
			return err
		}
		base, err := web.Templates.ReadFile("templates/layout.html")
		if err != nil {
			return err
		}
		t, err := template.New("layout").Funcs(funcs).Parse(string(base))
		if err != nil {
			return err
		}
		if _, err := t.Parse(string(content)); err != nil {
			return err
		}
		out[name] = t
		return nil
	})
	return out, err
}

func (h *Handler) render(w http.ResponseWriter, name string, data any) {
	t := h.tmpl[name]
	if t == nil {
		http.Error(w, "template not found", http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	if err := t.ExecuteTemplate(w, "layout", data); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}

func (h *Handler) pageData(w http.ResponseWriter, r *http.Request, title string, extra map[string]any) map[string]any {
	hasAdmin, _ := h.users.HasAdmin(r.Context())
	data := map[string]any{
		"Title":         title,
		"Domain":        h.domain,
		"Year":          "2026",
		"Flash":         flashGet(w, r),
		"CanRegister":   !hasAdmin,
		"HasAdmin":      hasAdmin,
	}
	if sess := h.currentUser(r); sess != nil {
		data["User"] = sess
	}
	for k, v := range extra {
		data[k] = v
	}
	return data
}