package test

import (
	"RenewCMS/api/pkg/apperr"
	domain "RenewCMS/internal/domain/image"
	"RenewCMS/internal/infrastructure/imaging"
	"RenewCMS/internal/infrastructure/useCases"
	"bytes"
	"errors"
	"net/http"
	"net/http/httptest"
	"runtime"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"
)

const (
	listedStoredName    = "a1b2.jpg"
	svgStoredName       = "e5f6.svg"
	imageNotFoundBody   = "Image not found"
	internalErrorBody   = "Internal server error"
	unreadableBodyBytes = "not an image at all"
)

func (e *variantEnv) seedPerImage(id uint32, filename string, storedName string, contentType string, width int, height int, content []byte) domain.Image {
	img := domain.Image{
		ID:          id,
		Path:        domain.PublicPath(storedName),
		Filename:    filename,
		Size:        int64(len(content)),
		ContentType: contentType,
		Width:       width,
		Height:      height,
		SHA256:      "hash-" + strconv.Itoa(int(id)),
		CreatedAt:   mockImageEpoch.Add(time.Duration(id) * time.Minute),
	}
	e.images.images[id] = img
	if id > e.images.nextID {
		e.images.nextID = id
	}
	if content != nil {
		e.storage.seed(storedName, content)
	}
	return img
}

func (e *variantEnv) seedCurrentFile(variantName string, storedName string, size int64) domain.VariantFile {
	cached := "cached-" + variantName + "-" + storedName
	e.storage.seed(cached, []byte("generated"))
	saved, _ := e.files.Save(domain.VariantFile{
		VariantName: variantName,
		SourceName:  storedName,
		CachedName:  cached,
		ContentType: "image/webp",
		Size:        size,
		Fingerprint: e.variants.stored(variantName).Settings().Fingerprint(),
	})
	return saved
}

func (e *variantEnv) disable(name string) {
	variant := e.variants.stored(name)
	variant.Enabled = false
	e.variants.variants[name] = variant
}

func (e *variantEnv) seedListingVariants() {
	seedVariant(e.variants, "card", 800, 0, domain.FitInside, domain.FormatWebP, 80)
	seedVariant(e.variants, "hero", 1200, 630, domain.FitCover, domain.FormatWebP, 82)
	seedVariant(e.variants, "og", 1200, 630, domain.FitCover, domain.FormatJPEG, 80)
	seedVariant(e.variants, "print", 0, 2400, domain.FitInside, domain.FormatPNG, 0)
	seedVariant(e.variants, "square", 600, 600, domain.FitCover, domain.FormatJPEG, 85)
	seedVariant(e.variants, "thumb", 400, 300, domain.FitCover, domain.FormatWebP, 80)
	e.disable("print")
}

func (e *variantEnv) seedListingBackground() {
	e.seedListingVariants()
	e.seedPerImage(1, "north-wall.jpg", listedStoredName, "image/jpeg", 4032, 3024, nil)
	e.images.images[1] = withSize(e.images.images[1], 4089446)
	e.seedPerImage(2, "logo.svg", svgStoredName, "image/svg+xml", 0, 0, nil)
	e.seedCurrentFile("thumb", listedStoredName, 18432)
	e.seedCurrentFile("card", listedStoredName, 65536)
	e.seedCurrentFile("hero", listedStoredName, 98304)
	e.seedCurrentFile("square", listedStoredName, 83968)
	e.seedCurrentFile("print", listedStoredName, 3250586)
}

func withSize(img domain.Image, size int64) domain.Image {
	img.Size = size
	return img
}

func (e *variantEnv) seedGenerateBackground() {
	e.seedVariantsForGeneration()
	e.seedPerImage(1, "north-wall.jpg", "a1b2.png", "image/png", 1000, 800, encodePNG(e.t, variantSolidImage(1000, 800, variantRed)))
}

func (e *variantEnv) seedVariantsForGeneration() {
	seedVariant(e.variants, "thumb", 400, 300, domain.FitCover, domain.FormatJPEG, 80)
	seedVariant(e.variants, "hero", 1200, 630, domain.FitCover, domain.FormatJPEG, 82)
	seedVariant(e.variants, "off", 300, 0, domain.FitInside, domain.FormatPNG, 0)
	e.disable("off")
}

func itemsOf(t *testing.T, recorder *httptest.ResponseRecorder) []map[string]any {
	t.Helper()
	raw, ok := decodeBody(t, recorder)["items"].([]any)
	if !ok {
		t.Fatalf("items missing in %q", recorder.Body.String())
	}
	items := make([]map[string]any, 0, len(raw))
	for _, entry := range raw {
		items = append(items, entry.(map[string]any))
	}
	return items
}

func itemNames(items []map[string]any) []string {
	names := make([]string, 0, len(items))
	for _, item := range items {
		names = append(names, item["name"].(string))
	}
	return names
}

func itemNamed(t *testing.T, items []map[string]any, name string) map[string]any {
	t.Helper()
	for _, item := range items {
		if item["name"] == name {
			return item
		}
	}
	t.Fatalf("no item named %q in %v", name, itemNames(items))
	return nil
}

func TestPerImageVariantRoutesAreGuarded(t *testing.T) {
	rows := []struct {
		method      string
		path        string
		credentials string
		status      int
		body        string
	}{
		{http.MethodGet, "/v1/media/1/variants", "none", 401, apperr.UnauthorizedErrorMessage},
		{http.MethodGet, "/v1/media/1/variants", "stale", 401, apperr.UnauthorizedErrorMessage},
		{http.MethodGet, "/v1/media/1/variants", "unverified", 403, apperr.VerificationRequiredErrorMessage},
		{http.MethodGet, "/v1/media/1/variants", "plain", 403, apperr.OwnerOrAdminRequiredErrorMessage},
		{http.MethodPost, "/v1/media/1/variants", "plain", 403, apperr.OwnerOrAdminRequiredErrorMessage},
		{http.MethodPost, "/v1/media/1/variants/hero", "plain", 403, apperr.OwnerOrAdminRequiredErrorMessage},
		{http.MethodDelete, "/v1/media/1/variants/hero", "plain", 403, apperr.OwnerOrAdminRequiredErrorMessage},
		{http.MethodGet, "/v1/media/1/variants", "apikey", 401, apperr.UnauthorizedErrorMessage},
		{http.MethodPost, "/v1/media/1/variants", "apikey", 401, apperr.UnauthorizedErrorMessage},
	}
	for _, row := range rows {
		t.Run("Every per-image variant route is guarded: "+row.method+" "+row.path+" "+row.credentials, func(t *testing.T) {
			env := newVariantEnv(t)
			env.seedGenerateBackground()
			variantCalls, fileCalls, opens := env.variants.calls, env.files.calls, env.storage.opens

			request := httptest.NewRequest(row.method, row.path, nil)
			switch row.credentials {
			case "stale":
				request.AddCookie(env.cookie(variantStaleId, 0))
			case "unverified":
				request.AddCookie(env.cookie(variantUnverifiedId, 0))
			case "plain":
				request.AddCookie(env.cookie(variantPlainUserId, 0))
			case "apikey":
				request.Header.Set("Authorization", "Bearer "+env.issueAPIKey())
			}
			recorder := httptest.NewRecorder()
			env.admin.ServeHTTP(recorder, request)

			assertStatusAndBody(t, recorder, row.status, row.body)
			if env.variants.calls != variantCalls || env.files.calls != fileCalls || env.storage.opens != opens || env.storage.putCount() != 0 || env.renderer.renderCount() != 0 || env.events() != 0 {
				t.Error("a variant, index row, blob or activity event was read or changed")
			}
		})
	}

	for name, userId := range map[string]uint32{"the owner": variantOwnerId, "an admin": variantAdminId} {
		t.Run("Owners and admins are both allowed: "+name, func(t *testing.T) {
			env := newVariantEnv(t)
			env.seedGenerateBackground()

			recorder := env.send(http.MethodGet, "/v1/media/1/variants", "", userId)

			if recorder.Code != http.StatusOK {
				t.Errorf("status = %d", recorder.Code)
			}
		})
	}
}

func TestPerImageVariantMalformedAndUnknown(t *testing.T) {
	rows := []struct {
		method string
		id     string
		suffix string
		status int
		body   string
	}{
		{http.MethodGet, "abc", "", 400, apperr.IdUint32ErrorMessage},
		{http.MethodPost, "abc", "", 400, apperr.IdUint32ErrorMessage},
		{http.MethodGet, "9999", "", 404, imageNotFoundBody},
		{http.MethodPost, "9999", "", 404, imageNotFoundBody},
		{http.MethodPost, "9999", "/hero", 404, imageNotFoundBody},
		{http.MethodDelete, "9999", "/hero", 404, imageNotFoundBody},
	}
	for _, row := range rows {
		t.Run("A malformed id or an unknown image: "+row.method+" "+row.id+row.suffix, func(t *testing.T) {
			env := newVariantEnv(t)
			env.seedGenerateBackground()

			recorder := env.sendAsAdmin(row.method, "/v1/media/"+row.id+"/variants"+row.suffix, "")

			assertStatusAndBody(t, recorder, row.status, row.body)
			if env.events() != 0 {
				t.Error("an activity event was recorded")
			}
		})
	}
}

func TestPerImageVariantListing(t *testing.T) {
	t.Run("The enabled variants, in name order, with their output and what is cached", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedListingBackground()

		recorder := env.sendAsAdmin(http.MethodGet, "/v1/media/1/variants", "")

		if recorder.Code != 200 || decodeBody(t, recorder)["unsupported"] != nil {
			t.Fatalf("response = %d %q", recorder.Code, recorder.Body.String())
		}
		items := itemsOf(t, recorder)
		if got := strings.Join(itemNames(items), ","); got != "card,hero,og,square,thumb" {
			t.Fatalf("names = %s", got)
		}
		expected := []struct {
			name, format        string
			width, height       any
			outWidth, outHeight float64
			generated           bool
			size                any
		}{
			{"card", "webp", 800.0, nil, 800, 600, true, 65536.0},
			{"hero", "webp", 1200.0, 630.0, 1200, 630, true, 98304.0},
			{"og", "jpeg", 1200.0, 630.0, 1200, 630, false, nil},
			{"square", "jpeg", 600.0, 600.0, 600, 600, true, 83968.0},
			{"thumb", "webp", 400.0, 300.0, 400, 300, true, 18432.0},
		}
		for _, want := range expected {
			item := itemNamed(t, items, want.name)
			if item["width"] != want.width || item["height"] != want.height || item["output_width"] != want.outWidth || item["output_height"] != want.outHeight || item["output_format"] != want.format || item["generated"] != want.generated || item["size"] != want.size {
				t.Errorf("%s = %v", want.name, item)
			}
		}
		if itemNamed(t, items, "thumb")["url"] != "/static/uploadedImages/a1b2.jpg?v=thumb" || itemNamed(t, items, "card")["fit"] != "inside" || itemNamed(t, items, "hero")["format"] != "webp" {
			t.Errorf("thumb = %v", itemNamed(t, items, "thumb"))
		}
		if !strings.Contains(recorder.Body.String(), `"height":null`) || !strings.Contains(recorder.Body.String(), `"size":null`) {
			t.Errorf("raw body = %q", recorder.Body.String())
		}
	})

	t.Run("A row whose fingerprint is stale is not generated", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedListingBackground()
		row, _, _ := env.files.Find("hero", listedStoredName)
		row.Fingerprint = "older-quality"
		_, _ = env.files.Save(row)

		recorder := env.sendAsAdmin(http.MethodGet, "/v1/media/1/variants", "")

		hero := itemNamed(t, itemsOf(t, recorder), "hero")
		if hero["generated"] != false || hero["size"] != nil {
			t.Errorf("hero = %v", hero)
		}
	})

	formats := []struct {
		contentType string
		webp        bool
		want        string
	}{
		{"image/jpeg", true, "jpeg"},
		{"image/png", true, "png"},
		{"image/webp", true, "webp"},
		{"image/webp", false, "png"},
	}
	for _, row := range formats {
		t.Run("A variant in the original format takes the format of the source: "+row.contentType+" webp "+strconv.FormatBool(row.webp), func(t *testing.T) {
			renderer := newCountingRenderer()
			if !row.webp {
				renderer = newCountingRendererWithoutWebP()
			}
			env := newVariantEnvWith(t, renderer, variantDefaultCap)
			seedVariant(env.variants, "keep", 100, 0, domain.FitInside, domain.FormatOriginal, 80)
			env.seedPerImage(1, "photo", "src.bin", row.contentType, 400, 300, nil)

			recorder := env.sendAsAdmin(http.MethodGet, "/v1/media/1/variants", "")

			if got := itemNamed(t, itemsOf(t, recorder), "keep")["output_format"]; got != row.want {
				t.Errorf("output_format = %v, want %s", got, row.want)
			}
		})
	}

	geometry := []struct {
		sw, sh, w, h int
		fit          domain.VariantFit
		ow, oh       float64
	}{
		{4032, 3024, 800, 0, domain.FitCover, 800, 600},
		{4032, 3024, 0, 2400, domain.FitInside, 3200, 2400},
		{4032, 3024, 8000, 8000, domain.FitCover, 3024, 3024},
		{300, 200, 800, 0, domain.FitCover, 300, 200},
		{300, 200, 400, 300, domain.FitCover, 267, 200},
		{300, 200, 400, 300, domain.FitContain, 400, 300},
		{300, 200, 1200, 1200, domain.FitInside, 300, 200},
	}
	for _, row := range geometry {
		name := strconv.Itoa(row.sw) + "x" + strconv.Itoa(row.sh) + " into " + strconv.Itoa(row.w) + "x" + strconv.Itoa(row.h) + " " + string(row.fit)
		t.Run("The output size never exceeds the source: "+name, func(t *testing.T) {
			env := newVariantEnv(t)
			variant := seedVariant(env.variants, "probe", row.w, row.h, row.fit, domain.FormatPNG, 0)
			env.seedPerImage(1, "photo", "src.png", "image/png", row.sw, row.sh, nil)

			recorder := env.sendAsAdmin(http.MethodGet, "/v1/media/1/variants", "")

			item := itemNamed(t, itemsOf(t, recorder), "probe")
			if item["output_width"] != row.ow || item["output_height"] != row.oh {
				t.Fatalf("output = %v x %v", item["output_width"], item["output_height"])
			}
			rendered, err := imaging.NewVariantRenderer().Render(bytes.NewReader(encodePNG(t, variantSolidImage(row.sw, row.sh, variantRed))), variant.Settings())
			if err != nil {
				t.Fatal(err)
			}
			width, height := decodedSize(t, rendered.Content)
			if float64(width) != row.ow || float64(height) != row.oh {
				t.Errorf("renderer produced %d x %d", width, height)
			}
		})
	}

	t.Run("A source that no variant can be generated for answers an empty list", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedListingBackground()

		recorder := env.sendAsAdmin(http.MethodGet, "/v1/media/2/variants", "")

		assertStatusAndBody(t, recorder, 200, `{"unsupported":"svg","items":[]}`)
	})

	t.Run("No enabled variant answers an empty array, not null", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedListingBackground()
		for _, name := range []string{"card", "hero", "og", "square", "thumb"} {
			env.disable(name)
		}

		recorder := env.sendAsAdmin(http.MethodGet, "/v1/media/1/variants", "")

		if recorder.Code != 200 || !strings.Contains(recorder.Body.String(), `"items":[]`) || !strings.Contains(recorder.Body.String(), `"unsupported":null`) {
			t.Errorf("response = %d %q", recorder.Code, recorder.Body.String())
		}
	})

	t.Run("Listing reads nothing it should not change", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedListingBackground()
		rows := env.files.rowCount()

		env.sendAsAdmin(http.MethodGet, "/v1/media/1/variants", "")

		if env.storage.opens != 0 || env.storage.putCount() != 0 || env.renderer.renderCount() != 0 || env.files.saves != 5 || env.files.rowCount() != rows || env.events() != 0 {
			t.Error("the listing opened a blob, rendered, wrote a row or recorded an event")
		}
	})
}

func TestPerImageVariantGenerateOne(t *testing.T) {
	t.Run("The first generation renders, stores and indexes the file", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")

		body := decodeBody(t, recorder)
		row, found, _ := env.files.Find("thumb", "a1b2.png")
		if recorder.Code != 200 || body["name"] != "thumb" || body["generated"] != true || body["output_width"] != 400.0 || body["output_height"] != 300.0 || body["output_format"] != "jpeg" || !found || body["size"] != float64(row.Size) {
			t.Fatalf("response = %d %q", recorder.Code, recorder.Body.String())
		}
		stored, _ := env.storage.Open(row.CachedName)
		if stored.Size != row.Size || env.storage.putCount() != 1 || env.files.rowCount() != 1 || len(env.storage.deletedNames()) != 0 || !env.storage.has("a1b2.png") || env.events() != 0 {
			t.Error("the generation changed more than the one blob and row")
		}
	})

	t.Run("The public url then serves that file without rendering", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()
		first := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")
		row, _, _ := env.files.Find("thumb", "a1b2.png")

		public := env.get("/static/uploadedImages/a1b2.png?v=thumb", nil)

		if first.Code != 200 || public.Code != 200 || !bytes.Equal(public.Body.Bytes(), env.storage.blobs[row.CachedName]) || env.renderer.renderCount() != 1 {
			t.Errorf("public = %d, renders = %d", public.Code, env.renderer.renderCount())
		}
	})

	t.Run("A file generated by the public url is a hit for the admin route", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()
		env.get("/static/uploadedImages/a1b2.png?v=thumb", nil)

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")

		if recorder.Code != 200 || env.renderer.renderCount() != 1 || env.storage.putCount() != 1 {
			t.Errorf("status = %d, renders = %d", recorder.Code, env.renderer.renderCount())
		}
	})

	t.Run("Generating a variant that is already generated renders nothing", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()
		first := decodeBody(t, env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", ""))

		again := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")

		if again.Code != 200 || decodeBody(t, again)["size"] != first["size"] || env.renderer.renderCount() != 1 {
			t.Errorf("status = %d, renders = %d", again.Code, env.renderer.renderCount())
		}
	})

	t.Run("A public request and an admin request at the same time render once", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()
		env.renderer.onRender = func() {
			for env.storage.openCountOf("a1b2.png") < 3 {
				runtime.Gosched()
			}
		}
		codes := make([]int, 2)
		start := make(chan struct{})
		var finished sync.WaitGroup
		finished.Add(2)
		go func() {
			defer finished.Done()
			<-start
			codes[0] = env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "").Code
		}()
		go func() {
			defer finished.Done()
			<-start
			codes[1] = env.get("/static/uploadedImages/a1b2.png?v=thumb", nil).Code
		}()
		close(start)
		finished.Wait()

		if codes[0] != 200 || codes[1] != 200 || env.renderer.renderCount() != 1 || env.storage.putCount() != 1 {
			t.Errorf("codes = %v, renders = %d, puts = %d", codes, env.renderer.renderCount(), env.storage.putCount())
		}
	})

	refused := []struct{ name, variant string }{{"unknown", "missing"}, {"disabled", "off"}, {"wrongly cased", "Thumb"}}
	for _, row := range refused {
		t.Run("A request that cannot be served: "+row.name, func(t *testing.T) {
			env := newVariantEnv(t)
			env.seedGenerateBackground()

			recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/"+row.variant, "")

			assertStatusAndBody(t, recorder, 404, variantNotFound)
			if env.renderer.renderCount() != 0 || env.storage.putCount() != 0 {
				t.Error("something was rendered or stored")
			}
		})
	}

	t.Run("An SVG answers 422", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()
		env.seedPerImage(2, "logo.svg", svgStoredName, "image/svg+xml", 0, 0, []byte("<svg/>"))

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/2/variants/thumb", "")

		assertStatusAndBody(t, recorder, 422, apperr.VariantSourceUnsupportedErrorMessage)
		if env.renderer.renderCount() != 0 || env.storage.putCount() != 0 {
			t.Error("something was rendered or stored")
		}
	})

	t.Run("A source beyond the byte cap answers 413", func(t *testing.T) {
		env := newVariantEnvWith(t, newCountingRenderer(), 10)
		env.seedGenerateBackground()

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")

		assertStatusAndBody(t, recorder, 413, apperr.VariantSourceTooLargeErrorMessage)
		if env.storage.putCount() != 0 {
			t.Error("a blob was stored")
		}
	})

	t.Run("A source beyond the pixel cap answers 413", func(t *testing.T) {
		env := newVariantEnvLimits(t, newCountingRenderer(), useCases.ServeVariantLimits{MaxSourceBytes: variantDefaultCap, MaxSourcePixels: 100, MaxConcurrentRenders: variantDefaultRenders})
		env.seedGenerateBackground()

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")

		assertStatusAndBody(t, recorder, 413, apperr.VariantSourceTooLargeErrorMessage)
		if env.storage.putCount() != 0 {
			t.Error("a blob was stored")
		}
	})

	t.Run("A source that cannot be decoded answers 415", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()
		env.storage.seed("a1b2.png", []byte(unreadableBodyBytes))

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")

		assertStatusAndBody(t, recorder, 415, apperr.VariantSourceUnreadableErrorMessage)
		if env.storage.putCount() != 0 {
			t.Error("a blob was stored")
		}
	})

	t.Run("Any other render failure is a generic 500 and is not cached", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()
		env.renderer.failFirst = true

		first := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")
		puts, rows := env.storage.putCount(), env.files.rowCount()
		second := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")

		assertStatusAndBody(t, first, 500, internalErrorBody)
		if puts != 0 || rows != 0 || second.Code != 200 {
			t.Errorf("puts = %d, rows = %d, second = %d", puts, rows, second.Code)
		}
	})

	t.Run("A generation does not change the original, the other variants or other images", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()
		env.seedPerImage(3, "other.png", "c3d4.png", "image/png", 10, 10, solidPNG(t, 10, 10))
		other := env.seedCurrentFile("hero", "c3d4.png", 5)
		before := env.images.images[1]

		env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")

		kept, _, _ := env.files.Find("hero", "c3d4.png")
		if env.images.images[1] != before || kept != other || env.files.rowCount() != 2 {
			t.Error("the original, another variant or another image changed")
		}
	})
}

func TestPerImageVariantGenerateAll(t *testing.T) {
	seedFive := func(env *variantEnv) {
		seedVariant(env.variants, "card", 800, 0, domain.FitInside, domain.FormatJPEG, 80)
		seedVariant(env.variants, "hero", 1200, 630, domain.FitCover, domain.FormatJPEG, 82)
		seedVariant(env.variants, "og", 1200, 630, domain.FitCover, domain.FormatJPEG, 80)
		seedVariant(env.variants, "print", 0, 2400, domain.FitInside, domain.FormatPNG, 0)
		seedVariant(env.variants, "square", 600, 600, domain.FitCover, domain.FormatJPEG, 85)
		seedVariant(env.variants, "thumb", 400, 300, domain.FitCover, domain.FormatJPEG, 80)
		env.disable("print")
		env.seedPerImage(1, "north-wall.jpg", "a1b2.png", "image/png", 1000, 800, encodePNG(env.t, variantSolidImage(1000, 800, variantRed)))
	}

	t.Run("Generate all renders every enabled variant and answers the refreshed list", func(t *testing.T) {
		env := newVariantEnv(t)
		seedFive(env)

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants", "")

		body := decodeBody(t, recorder)
		items := itemsOf(t, recorder)
		if recorder.Code != 200 || body["generated"] != 5.0 || body["failed"] != 0.0 || !strings.Contains(recorder.Body.String(), `"failures":[]`) || len(items) != 5 {
			t.Fatalf("response = %d %q", recorder.Code, recorder.Body.String())
		}
		for _, item := range items {
			if item["generated"] != true || item["size"] == nil {
				t.Errorf("item = %v", item)
			}
		}
		if env.storage.putCount() != 5 || env.files.rowCount() != 5 || len(env.files.rowsOf("print")) != 0 {
			t.Error("expected exactly five blobs and rows, none for the disabled variant")
		}
	})

	t.Run("Variants already generated are skipped and not counted", func(t *testing.T) {
		env := newVariantEnv(t)
		seedFive(env)
		env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/card", "")
		env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants", "")

		generated := decodeBody(t, recorder)["generated"]
		if generated != 3.0 || env.renderer.renderCount() != 5 {
			t.Errorf("generated = %v, renders = %d", generated, env.renderer.renderCount())
		}
		for _, item := range itemsOf(t, recorder) {
			if item["generated"] != true {
				t.Errorf("item = %v", item)
			}
		}
	})

	failures := []struct {
		name  string
		fail  error
		cause string
	}{
		{"ErrSourceTooLarge", domain.ErrSourceTooLarge, "too_large"},
		{"ErrVariantSourceUnreadable", domain.ErrVariantSourceUnreadable, "unsupported_format"},
		{"a renderer error that wraps no sentinel", errors.New("boom"), "failed"},
	}
	for _, row := range failures {
		t.Run("A failing variant is reported and the others are still generated: "+row.name, func(t *testing.T) {
			env := newVariantEnv(t)
			seedFive(env)
			heroFingerprint := env.variants.stored("hero").Settings().Fingerprint()
			env.renderer.failFor = func(settings domain.VariantSettings) error {
				if settings.Fingerprint() == heroFingerprint {
					return row.fail
				}
				return nil
			}

			recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants", "")

			body := decodeBody(t, recorder)
			failed, _ := body["failures"].([]any)
			if recorder.Code != 200 || body["generated"] != 4.0 || body["failed"] != 1.0 || len(failed) != 1 || failed[0].(map[string]any)["name"] != "hero" || failed[0].(map[string]any)["cause"] != row.cause {
				t.Fatalf("response = %d %q", recorder.Code, recorder.Body.String())
			}
			for _, item := range itemsOf(t, recorder) {
				if (item["name"] == "hero") == (item["generated"] == true) {
					t.Errorf("item = %v", item)
				}
			}
		})
	}

	t.Run("Nothing to generate answers zero", func(t *testing.T) {
		env := newVariantEnv(t)
		seedFive(env)
		env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants", "")
		rendered := env.renderer.renderCount()

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants", "")

		body := decodeBody(t, recorder)
		if recorder.Code != 200 || body["generated"] != 0.0 || body["failed"] != 0.0 || env.renderer.renderCount() != rendered {
			t.Errorf("response = %d %q", recorder.Code, recorder.Body.String())
		}
	})

	t.Run("No enabled variant answers zero", func(t *testing.T) {
		env := newVariantEnv(t)
		seedFive(env)
		for _, name := range []string{"card", "hero", "og", "square", "thumb"} {
			env.disable(name)
		}

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants", "")

		body := decodeBody(t, recorder)
		if recorder.Code != 200 || body["generated"] != 0.0 || body["failed"] != 0.0 || !strings.Contains(recorder.Body.String(), `"items":[]`) {
			t.Errorf("response = %d %q", recorder.Code, recorder.Body.String())
		}
	})

	t.Run("An SVG answers 422", func(t *testing.T) {
		env := newVariantEnv(t)
		seedFive(env)
		env.seedPerImage(2, "logo.svg", svgStoredName, "image/svg+xml", 0, 0, []byte("<svg/>"))

		recorder := env.sendAsAdmin(http.MethodPost, "/v1/media/2/variants", "")

		assertStatusAndBody(t, recorder, 422, apperr.VariantSourceUnsupportedErrorMessage)
	})
}

func TestPerImageVariantPurge(t *testing.T) {
	seedBoth := func(env *variantEnv) {
		seedVariant(env.variants, "thumb", 400, 300, domain.FitCover, domain.FormatJPEG, 80)
		seedVariant(env.variants, "hero", 1200, 630, domain.FitCover, domain.FormatJPEG, 82)
		env.seedPerImage(1, "north-wall.jpg", "a1b2.jpg", "image/jpeg", 100, 100, nil)
		env.seedPerImage(3, "other.jpg", "c3d4.jpg", "image/jpeg", 100, 100, nil)
		for _, source := range []string{"a1b2.jpg", "c3d4.jpg"} {
			env.seedCurrentFile("thumb", source, 18432)
			env.seedCurrentFile("hero", source, 98304)
		}
	}

	t.Run("Purging a generated variant removes its file and its row", func(t *testing.T) {
		env := newVariantEnv(t)
		seedBoth(env)

		recorder := env.sendAsAdmin(http.MethodDelete, "/v1/media/1/variants/thumb", "")

		assertStatusAndBody(t, recorder, 200, `{"purged_files":1,"purged_bytes":18432}`)
		if got := strings.Join(env.storage.deletedNames(), ","); got != "cached-thumb-a1b2.jpg" {
			t.Errorf("deleted = %s", got)
		}
		if _, found, _ := env.files.Find("thumb", "a1b2.jpg"); found || env.files.rowCount() != 3 {
			t.Error("the row is still there, or another row went with it")
		}
	})

	t.Run("The next public request generates the file again", func(t *testing.T) {
		env := newVariantEnv(t)
		env.seedGenerateBackground()
		env.sendAsAdmin(http.MethodPost, "/v1/media/1/variants/thumb", "")
		env.sendAsAdmin(http.MethodDelete, "/v1/media/1/variants/thumb", "")
		puts := env.storage.putCount()

		public := env.get("/static/uploadedImages/a1b2.png?v=thumb", nil)

		if public.Code != 200 || env.storage.putCount() != puts+1 {
			t.Errorf("status = %d, puts = %d", public.Code, env.storage.putCount())
		}
	})

	t.Run("Purging a variant that is not generated answers zero", func(t *testing.T) {
		env := newVariantEnv(t)
		seedBoth(env)
		row, _, _ := env.files.Find("thumb", "a1b2.jpg")
		_ = env.files.Delete(row.ID)

		recorder := env.sendAsAdmin(http.MethodDelete, "/v1/media/1/variants/thumb", "")

		assertStatusAndBody(t, recorder, 200, `{"purged_files":0,"purged_bytes":0}`)
	})

	t.Run("A disabled variant keeps its files and they can be purged", func(t *testing.T) {
		env := newVariantEnv(t)
		seedBoth(env)
		env.disable("thumb")

		recorder := env.sendAsAdmin(http.MethodDelete, "/v1/media/1/variants/thumb", "")

		if decodeBody(t, recorder)["purged_files"] != 1.0 {
			t.Errorf("body = %q", recorder.Body.String())
		}
	})

	t.Run("An unknown variant answers 404", func(t *testing.T) {
		env := newVariantEnv(t)
		seedBoth(env)

		recorder := env.sendAsAdmin(http.MethodDelete, "/v1/media/1/variants/missing", "")

		assertStatusAndBody(t, recorder, 404, variantNotFound)
	})

	t.Run("A blob that cannot be deleted keeps its row and the call fails", func(t *testing.T) {
		env := newVariantEnv(t)
		seedBoth(env)
		env.storage.failDelete["cached-thumb-a1b2.jpg"] = errVariantStorageFailure

		recorder := env.sendAsAdmin(http.MethodDelete, "/v1/media/1/variants/thumb", "")

		assertStatusAndBody(t, recorder, 500, internalErrorBody)
		if _, found, _ := env.files.Find("thumb", "a1b2.jpg"); !found {
			t.Error("the index row was removed")
		}
	})
}