package handlers

import (
	"html/template"
	"log"
	"path/filepath"
	"sync"
)

var (
	templatesOnce sync.Once
	templates     map[string]*template.Template
)

// getTemplate returns a cached template by filename (e.g. "dashboard.html").
// Templates are parsed once from the templates/ directory on first call.
func getTemplate(name string) *template.Template {
	templatesOnce.Do(loadTemplates)
	t := templates[name]
	if t == nil {
		log.Panicf("template %q not found in cache — did you delete templates/%s?", name, name)
	}
	return t
}

// loadTemplates walks the templates/ directory and pre-parses all .html files.
func loadTemplates() {
	templates = make(map[string]*template.Template)

	files, err := filepath.Glob("templates/*.html")
	if err != nil {
		log.Panicf("list templates: %v", err)
	}

	// Parse each file into its own named template.
	for _, f := range files {
		name := filepath.Base(f)
		t, err := template.ParseFiles(f)
		if err != nil {
			log.Panicf("parse template %s: %v", f, err)
		}
		templates[name] = t
	}

	// Also register the inline OTP form template.
	otpTmpl := template.Must(template.New("otp_form").Parse(otpFormHTML))
	templates["otp_form"] = otpTmpl

	log.Printf("Loaded %d templates", len(templates))
}

// otpFormHTML is the inline OTP form template fragment with single 6-digit field.
const otpFormHTML = `
<form hx-post="/verify-otp" hx-target="#otp-form" hx-swap="innerHTML">
    <input type="hidden" name="email" value="{{.Email}}">
    {{if .Error}}<div class="error-message" style="color: #fca5a5; background: #450a0a; border: 1px solid #7f1d1d; padding: 0.75rem; border-radius: 0.5rem; margin-bottom: 1rem;">{{.Error}}</div>{{end}}
    <div class="form-group" style="margin: 1rem 0;">
        <input type="text" name="otp_code" inputmode="numeric" pattern="[0-9]{6}" maxlength="6" autocomplete="one-time-code" required
               placeholder="Enter 6-digit code"
               style="width: 100%; padding: 1rem; font-size: 1.5rem; text-align: center; letter-spacing: 0.75rem; border: 2px solid #475569; border-radius: 0.5rem; background: #1e293b; color: #f8fafc; box-sizing: border-box;">
    </div>
    <button type="submit" class="btn btn-primary btn-block">Verify Code</button>
</form>`