package main

import (
	"bytes"
	"image"
	"image/jpeg"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// buildSite builds a site of three photos spread over two days, with a page
// size of two so both views need a second page, and returns the output dir.
func buildSite(t *testing.T, output, defaultView string) {
	t.Helper()
	content := t.TempDir()

	var img bytes.Buffer
	if err := jpeg.Encode(&img, image.NewRGBA(image.Rect(0, 0, 8, 8)), nil); err != nil {
		t.Fatal(err)
	}
	for slug, date := range map[string]string{
		"one":   "2026-06-14",
		"two":   "2026-06-14",
		"three": "2026-06-10",
	} {
		writeFile(t, filepath.Join(content, slug+".jpg"), img.Bytes())
		writeFile(t, filepath.Join(content, slug+".toml"),
			[]byte("caption = \""+slug+"\"\ndate = \""+date+"\"\n"))
	}

	g := NewGenerator(content, output, "https://photos.example.com",
		"Ada", "", "", "", "", "Crimson Pro", "Manjari", 2, defaultView)
	if err := g.Build(); err != nil {
		t.Fatal(err)
	}
}

func writeFile(t *testing.T, path string, data []byte) {
	t.Helper()
	if err := os.WriteFile(path, data, 0644); err != nil {
		t.Fatal(err)
	}
}

func readPage(t *testing.T, output, rel string) string {
	t.Helper()
	data, err := os.ReadFile(filepath.Join(output, filepath.FromSlash(rel), "index.html"))
	if err != nil {
		t.Fatal(err)
	}
	return string(data)
}

// Timeline pages carry day sections, grid pages do not.
func isTimeline(page string) bool {
	return strings.Contains(page, `class="tl-day"`)
}

func TestDefaultViewOwnsSiteRoot(t *testing.T) {
	tests := []struct {
		defaultView string
		gridAt      string // URL of the grid's first page
		timelineAt  string // URL of the timeline's first page
	}{
		{viewTimeline, "/grid/", "/"},
		{viewGrid, "/", "/timeline/"},
		{"nonsense", "/grid/", "/"}, // unknown values fall back to the timeline
	}
	for _, tt := range tests {
		t.Run(tt.defaultView, func(t *testing.T) {
			output := t.TempDir()
			buildSite(t, output, tt.defaultView)

			timeline := readPage(t, output, tt.timelineAt)
			grid := readPage(t, output, tt.gridAt)
			if !isTimeline(timeline) {
				t.Errorf("%s is not the timeline", tt.timelineAt)
			}
			if isTimeline(grid) {
				t.Errorf("%s is not the grid", tt.gridAt)
			}

			// The views link to each other, and to their own second page.
			for page, want := range map[string]string{
				timeline: `href="` + tt.gridAt + `" class="rss-a">Grid`,
				grid:     `href="` + tt.timelineAt + `" class="rss-a">Timeline`,
			} {
				if !strings.Contains(page, want) {
					t.Errorf("missing link %q", want)
				}
			}
			for first, base := range map[string]string{
				timeline: strings.TrimSuffix(tt.timelineAt, "/"),
				grid:     strings.TrimSuffix(tt.gridAt, "/"),
			} {
				next := base + "/page/2/"
				if !strings.Contains(first, `href="`+next+`" data-load-more`) {
					t.Errorf("first page does not link to %s", next)
				}
				second := readPage(t, output, next)
				if !strings.Contains(second, `class="pager-newer" href="`+base+`/"`) {
					t.Errorf("%s does not link back to %s/", next, base)
				}
			}

			// Day pages lead back to the timeline, wherever it lives.
			day := readPage(t, output, "/day/2026-06-14/")
			if !strings.Contains(day, `href="`+tt.timelineAt+`" class="rss-a">← Timeline`) {
				t.Errorf("day page does not link to the timeline at %s", tt.timelineAt)
			}
		})
	}
}

func TestSwitchingDefaultViewDropsOldViewDir(t *testing.T) {
	output := t.TempDir()

	buildSite(t, output, viewTimeline)
	if _, err := os.Stat(filepath.Join(output, "grid", "index.html")); err != nil {
		t.Fatalf("grid view missing before the switch: %v", err)
	}

	buildSite(t, output, viewGrid)
	if _, err := os.Stat(filepath.Join(output, "grid")); !os.IsNotExist(err) {
		t.Errorf("stale /grid/ survived the switch to -default-view grid")
	}
	if isTimeline(readPage(t, output, "/")) {
		t.Errorf("site root is still the timeline")
	}
}