package templates_test

import (
	"bytes"
	"html/template"
	"strings"
	"testing"

	"git.eeqj.de/sneak/routewatch/internal/templates"
)

// renderPage renders a page with the data every page needs.
func renderPage(t *testing.T, tmpl *template.Template) string {
	t.Helper()

	var page bytes.Buffer

	err := tmpl.Execute(&page, struct{ CSPNonce string }{})
	if err != nil {
		t.Fatalf("rendering the page: %v", err)
	}

	return page.String()
}

// TestFooterLicense renders the home and status pages and expects each footer
// to name the licence in LICENSE, MIT, and not WTFPL.
func TestFooterLicense(t *testing.T) {
	t.Parallel()

	const (
		license      = "MIT"
		wrongLicense = "WTFPL"
	)

	pages := map[string]*template.Template{
		"index":  templates.IndexTemplate(),
		"status": templates.StatusTemplate(),
	}

	for name, tmpl := range pages {
		t.Run(name, func(t *testing.T) {
			t.Parallel()

			_, footer, found := strings.Cut(renderPage(t, tmpl), "<footer")
			if !found {
				t.Fatal("the page has no footer")
			}

			footer, _, _ = strings.Cut(footer, "</footer>")

			if !strings.Contains(footer, license) {
				t.Errorf("footer does not name %s: %q", license, footer)
			}

			if strings.Contains(footer, wrongLicense) {
				t.Errorf("footer names %s: %q", wrongLicense, footer)
			}
		})
	}
}

// TestFreshnessIndicator renders the home and status pages and expects each to
// have, right after the status element, the element where the page's script
// shows its spinner or "stale".
func TestFreshnessIndicator(t *testing.T) {
	t.Parallel()

	pages := map[string]struct {
		tmpl      *template.Template
		status    string
		indicator string
	}{
		"index": {
			tmpl:      templates.IndexTemplate(),
			status:    `<span id="stat-status">-</span>`,
			indicator: `<span id="freshness"></span>`,
		},
		"status": {
			tmpl:      templates.StatusTemplate(),
			status:    `<span class="metric-value" id="connected">-</span>`,
			indicator: `<span class="metric-value" id="freshness"></span>`,
		},
	}

	for name, page := range pages {
		t.Run(name, func(t *testing.T) {
			t.Parallel()

			_, afterStatus, found := strings.Cut(renderPage(t, page.tmpl), page.status)
			if !found {
				t.Fatalf("the page has no status element %s", page.status)
			}

			if !strings.HasPrefix(strings.TrimSpace(afterStatus), page.indicator) {
				t.Errorf("the status element is not followed by %s", page.indicator)
			}
		})
	}
}