package web

import (
	"bytes"
	"fmt"
	"html/template"
	"net/http"
	"strings"
	"time"
)

// pageNames are the templates with a full page each; "layout" wraps them. Fragments (for htmx) are defined inside
// page files and rendered on their own.
var pageNames = []string{"home", "signin", "signup", "account", "device", "online", "console", "console_people",
	"console_person", "error"}

var funcs = template.FuncMap{
	"ago": func(t time.Time) string {
		d := time.Since(t)
		switch {
		case d < time.Minute:
			return "just now"
		case d < time.Hour:
			return fmt.Sprintf("%d min ago", int(d.Minutes()))
		case d < 48*time.Hour:
			return fmt.Sprintf("%d h ago", int(d.Hours()))
		}
		return t.Format("2 Jan 2006")
	},
	"date":  func(t time.Time) string { return t.Format("2 Jan 2006 15:04") },
	"upper": strings.ToUpper,
}

func (s *Server) parseTemplates() error {
	s.pages = map[string]*template.Template{}
	for _, name := range pageNames {
		t, err := template.New("layout.html").Funcs(funcs).ParseFS(templateFiles, "templates/layout.html", "templates/"+name+".html")
		if err != nil {
			return err
		}
		s.pages[name] = t
	}
	return nil
}

// render shows a page in the layout. data is the page's own values; the layout gets the person and CSRF token.
func (s *Server) render(q *request, name string, data map[string]any) {
	if data == nil {
		data = map[string]any{}
	}
	data["Person"] = q.person
	data["CSRF"] = q.csrf
	data["Flash"] = q.flash
	data["Page"] = name
	var buf bytes.Buffer
	if err := s.pages[name].ExecuteTemplate(&buf, "layout.html", data); err != nil {
		s.Log.Printf("rendering %s: %v", name, err)
		http.Error(q.w, "Something went wrong on our side.", http.StatusInternalServerError)
		return
	}
	q.w.Header().Set("Content-Type", "text/html; charset=utf-8")
	q.w.Header().Set("Cache-Control", "no-store")
	buf.WriteTo(q.w)
}

// fragment shows one template from a page's file, without the layout (htmx swaps it in).
func (s *Server) fragment(q *request, page, name string, data map[string]any) {
	if data == nil {
		data = map[string]any{}
	}
	data["Person"] = q.person
	data["CSRF"] = q.csrf
	var buf bytes.Buffer
	if err := s.pages[page].ExecuteTemplate(&buf, name, data); err != nil {
		s.Log.Printf("rendering %s/%s: %v", page, name, err)
		http.Error(q.w, "Something went wrong on our side.", http.StatusInternalServerError)
		return
	}
	q.w.Header().Set("Content-Type", "text/html; charset=utf-8")
	q.w.Header().Set("Cache-Control", "no-store")
	buf.WriteTo(q.w)
}