package web

import (
	"bytes"
	"context"
	"errors"
	"image"
	"image/color"
	"image/jpeg"
	"image/png"
	"io"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"sync"
	"testing"

	"plumber/internal/blob"
	"plumber/internal/pacific"
	"plumber/internal/store"
)

func TestPreparePostImage(t *testing.T) {
	t.Parallel()

	wide := solidPNG(t, 2000, 1000)
	prepared, err := preparePostImageHeader(t, "wide.png", wide)
	if err != nil {
		t.Fatal(err)
	}
	if prepared.width != 1600 || prepared.height != 800 ||
		prepared.extension != ".png" || prepared.contentType != "image/png" {
		t.Fatalf("prepared PNG = %+v", prepared)
	}

	jpegBody := solidJPEG(t, 40, 20)
	prepared, err = preparePostImageHeader(t, "photo.jpg", jpegBody)
	if err != nil {
		t.Fatal(err)
	}
	if prepared.width != 40 || prepared.height != 20 ||
		prepared.extension != ".jpg" || prepared.contentType != "image/jpeg" {
		t.Fatalf("prepared JPEG = %+v", prepared)
	}

	if _, err := preparePostImageHeader(t, "notes.txt", []byte("not an image")); err == nil {
		t.Fatal("text upload unexpectedly succeeded")
	}
	_, err = preparePostImageHeader(t, "too-large.jpg", make([]byte, postImageMaxFileBytes+1))
	var requestErr *postImageRequestError
	if !errors.As(err, &requestErr) || requestErr.status != http.StatusRequestEntityTooLarge {
		t.Fatalf("oversized file error = %v, want 413 request error", err)
	}
	if _, err := preparePostImageHeader(t, "too-wide.png", solidPNG(t, 6001, 1)); err == nil {
		t.Fatal("oversized dimensions unexpectedly succeeded")
	}
}

func TestOrientPostImage(t *testing.T) {
	t.Parallel()

	source := image.NewNRGBA(image.Rect(0, 0, 2, 1))
	source.Set(0, 0, color.NRGBA{R: 255, A: 255})
	source.Set(1, 0, color.NRGBA{B: 255, A: 255})
	rotated := orientPostImage(source, 6)
	if rotated.Bounds().Dx() != 1 || rotated.Bounds().Dy() != 2 {
		t.Fatalf("rotated bounds = %v", rotated.Bounds())
	}
	top := color.NRGBAModel.Convert(rotated.At(0, 0)).(color.NRGBA)
	bottom := color.NRGBAModel.Convert(rotated.At(0, 1)).(color.NRGBA)
	if top.R != 255 || bottom.B != 255 {
		t.Fatalf("rotation colors top=%v bottom=%v", top, bottom)
	}
}

func TestPostImageMultipartLifecycle(t *testing.T) {
	t.Parallel()

	images := &recordingImageBlob{}
	srv, mem := newTestServer(t, Config{Blob: images})
	handler := srv.Handler()
	homeowner := seedUser(t, mem, uniq("images"), "hunter22", store.RoleUser)
	cookies := loginUser(t, handler, homeowner.Username, "hunter22")
	csrf := csrfForCookies(t, handler, cookies)

	rec := multipartPost(t, handler, "/submit", map[string][]string{
		"_csrf":             {csrf},
		"title":             {"Leaky valve"},
		"body":              {"Two views of the leak."},
		"city":              {"Oakland"},
		"image_description": {"Front view", "Under the sink"},
	}, []multipartTestFile{
		{name: "front.png", body: solidPNG(t, 80, 40)},
		{name: "under.jpg", body: solidJPEG(t, 40, 80)},
	}, cookies)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("root image upload status = %d: %s", rec.Code, rec.Body.String())
	}
	roots, err := mem.ListRootPosts(context.Background(), pacific.Today(), homeowner.ID)
	if err != nil || len(roots) != 1 {
		t.Fatalf("roots = %+v, %v", roots, err)
	}
	root, err := mem.GetPost(context.Background(), roots[0].ID)
	if err != nil {
		t.Fatal(err)
	}
	if len(root.Images) != 2 ||
		root.Images[0].Description != "Front view" ||
		root.Images[1].Description != "Under the sink" {
		t.Fatalf("root images = %+v", root.Images)
	}

	rec = multipartPost(t, handler, "/posts", map[string][]string{
		"_csrf":             {csrf},
		"parent_id":         {root.ID},
		"body":              {"Here is the model label."},
		"image_description": {"Model label"},
	}, []multipartTestFile{{name: "label.png", body: solidPNG(t, 60, 30)}}, cookies)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("reply image upload status = %d: %s", rec.Code, rec.Body.String())
	}
	thread, err := mem.GetPostThread(context.Background(), root.ID)
	if err != nil || len(thread.Replies) != 1 {
		t.Fatalf("thread = %+v, %v", thread, err)
	}
	reply := thread.Replies[0]
	if len(reply.Images) != 1 || reply.Images[0].Description != "Model label" {
		t.Fatalf("reply images = %+v", reply.Images)
	}
	originalKey := reply.Images[0].ObjectKey

	rec = multipartPost(t, handler, "/posts/"+reply.ID+"/edit", map[string][]string{
		"_csrf":                      {csrf},
		"body":                       {"Updated label photos."},
		"existing_image_id":          {reply.Images[0].ID},
		"existing_image_description": {"Existing label"},
		"image_description":          {"Serial number"},
	}, []multipartTestFile{{name: "serial.jpg", body: solidJPEG(t, 50, 25)}}, cookies)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("image edit status = %d: %s", rec.Code, rec.Body.String())
	}
	edited, err := mem.GetPost(context.Background(), reply.ID)
	if err != nil {
		t.Fatal(err)
	}
	if len(edited.Images) != 2 ||
		edited.Images[0].Description != "Existing label" ||
		edited.Images[1].Description != "Serial number" {
		t.Fatalf("edited images = %+v", edited.Images)
	}

	rec = multipartPost(t, handler, "/posts/"+reply.ID+"/edit", map[string][]string{
		"_csrf":                      {csrf},
		"body":                       {"Keep only the serial number."},
		"existing_image_id":          {edited.Images[1].ID},
		"existing_image_description": {"Serial number"},
	}, nil, cookies)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("image removal status = %d: %s", rec.Code, rec.Body.String())
	}
	edited, err = mem.GetPost(context.Background(), reply.ID)
	if err != nil {
		t.Fatal(err)
	}
	if len(edited.Images) != 1 || edited.Images[0].Description != "Serial number" {
		t.Fatalf("images after removal = %+v", edited.Images)
	}
	if !images.wasDeleted(originalKey) {
		t.Fatalf("removed object %q was not deleted: %+v", originalKey, images.deletedKeys())
	}

	uploadsBefore := images.uploadCount()
	rec = multipartPost(t, handler, "/posts/"+reply.ID+"/edit", map[string][]string{
		"_csrf":             {csrf},
		"body":              {"Invalid retained image."},
		"existing_image_id": {"not-owned"},
	}, nil, cookies)
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("invalid retained image status = %d, want 400", rec.Code)
	}
	unchanged, err := mem.GetPost(context.Background(), reply.ID)
	if err != nil {
		t.Fatal(err)
	}
	if unchanged.Body != "Keep only the serial number." || len(unchanged.Images) != 1 {
		t.Fatalf("invalid retained image changed post: %+v", unchanged)
	}

	files := make([]multipartTestFile, store.MaxPostImages+1)
	for i := range files {
		files[i] = multipartTestFile{name: "extra.png", body: solidPNG(t, 10, 10)}
	}
	rec = multipartPost(t, handler, "/posts", map[string][]string{
		"_csrf":     {csrf},
		"parent_id": {root.ID},
		"body":      {"Too many images."},
	}, files, cookies)
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("five-image status = %d, want 400", rec.Code)
	}
	if images.uploadCount() != uploadsBefore {
		t.Fatal("five-image request uploaded objects before rejecting count")
	}
}

func TestPostImageUploadCompensation(t *testing.T) {
	t.Parallel()

	t.Run("blob failure deletes earlier upload", func(t *testing.T) {
		images := &recordingImageBlob{failAt: 2}
		srv, mem := newTestServer(t, Config{Blob: images})
		handler := srv.Handler()
		user := seedUser(t, mem, uniq("blob-fail"), "hunter22", store.RoleUser)
		cookies := loginUser(t, handler, user.Username, "hunter22")
		csrf := csrfForCookies(t, handler, cookies)
		rec := multipartPost(t, handler, "/submit", map[string][]string{
			"_csrf": {csrf},
			"title": {"Upload failure"},
			"body":  {"Should not persist."},
		}, []multipartTestFile{
			{name: "one.png", body: solidPNG(t, 10, 10)},
			{name: "two.png", body: solidPNG(t, 10, 10)},
		}, cookies)
		if rec.Code != http.StatusServiceUnavailable {
			t.Fatalf("blob failure status = %d: %s", rec.Code, rec.Body.String())
		}
		if images.uploadCount() != 1 || len(images.deletedKeys()) != 1 {
			t.Fatalf("blob compensation uploads=%d deletes=%v", images.uploadCount(), images.deletedKeys())
		}
	})

	t.Run("store failure deletes uploaded object", func(t *testing.T) {
		images := &recordingImageBlob{}
		mem := store.NewMemory()
		failing := &failingCreatePostStore{Store: mem}
		srv := newTestServerStore(t, failing, Config{Blob: images})
		handler := srv.Handler()
		user := seedUser(t, mem, uniq("store-fail"), "hunter22", store.RoleUser)
		cookies := loginUser(t, handler, user.Username, "hunter22")
		csrf := csrfForCookies(t, handler, cookies)
		rec := multipartPost(t, handler, "/submit", map[string][]string{
			"_csrf": {csrf},
			"title": {"Store failure"},
			"body":  {"Should clean up."},
		}, []multipartTestFile{{name: "one.png", body: solidPNG(t, 10, 10)}}, cookies)
		if rec.Code != http.StatusInternalServerError {
			t.Fatalf("store failure status = %d: %s", rec.Code, rec.Body.String())
		}
		if images.uploadCount() != 1 || len(images.deletedKeys()) != 1 {
			t.Fatalf("store compensation uploads=%d deletes=%v", images.uploadCount(), images.deletedKeys())
		}
	})
}

func TestPostImageRequestLimits(t *testing.T) {
	t.Parallel()

	for _, test := range []struct {
		method string
		path   string
		want   int64
	}{
		{http.MethodPost, "/submit", postImageMaxRequestBytes},
		{http.MethodPost, "/posts", postImageMaxRequestBytes},
		{http.MethodPost, "/posts/id/edit", postImageMaxRequestBytes},
		{http.MethodPost, "/login", defaultRequestBodyBytes},
		{http.MethodGet, "/posts", defaultRequestBodyBytes},
	} {
		req := httptest.NewRequest(test.method, test.path, nil)
		if got := requestBodyLimit(req); got != test.want {
			t.Errorf("%s %s limit = %d, want %d", test.method, test.path, got, test.want)
		}
	}
}

type multipartTestFile struct {
	name string
	body []byte
}

func multipartPost(
	t *testing.T,
	handler http.Handler,
	requestPath string,
	fields map[string][]string,
	files []multipartTestFile,
	cookies []*http.Cookie,
) *httptest.ResponseRecorder {
	t.Helper()
	var body bytes.Buffer
	writer := multipart.NewWriter(&body)
	for name, values := range fields {
		for _, value := range values {
			if err := writer.WriteField(name, value); err != nil {
				t.Fatal(err)
			}
		}
	}
	for _, file := range files {
		part, err := writer.CreateFormFile("images", file.name)
		if err != nil {
			t.Fatal(err)
		}
		if _, err := part.Write(file.body); err != nil {
			t.Fatal(err)
		}
	}
	if err := writer.Close(); err != nil {
		t.Fatal(err)
	}
	req := httptest.NewRequest(http.MethodPost, requestPath, &body)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	for _, cookie := range cookies {
		req.AddCookie(cookie)
	}
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	return rec
}

func preparePostImageHeader(t *testing.T, name string, body []byte) (preparedPostImage, error) {
	t.Helper()
	var requestBody bytes.Buffer
	writer := multipart.NewWriter(&requestBody)
	part, err := writer.CreateFormFile("images", name)
	if err != nil {
		t.Fatal(err)
	}
	if _, err := part.Write(body); err != nil {
		t.Fatal(err)
	}
	if err := writer.Close(); err != nil {
		t.Fatal(err)
	}
	req := httptest.NewRequest(http.MethodPost, "/posts", &requestBody)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	if err := req.ParseMultipartForm(postImageMultipartMemory); err != nil {
		t.Fatal(err)
	}
	defer req.MultipartForm.RemoveAll()
	return preparePostImage(req.MultipartForm.File["images"][0])
}

func solidPNG(t *testing.T, width, height int) []byte {
	t.Helper()
	img := image.NewNRGBA(image.Rect(0, 0, width, height))
	for y := 0; y < height; y++ {
		for x := 0; x < width; x++ {
			img.Set(x, y, color.NRGBA{R: 30, G: 90, B: 140, A: 255})
		}
	}
	var out bytes.Buffer
	if err := png.Encode(&out, img); err != nil {
		t.Fatal(err)
	}
	return out.Bytes()
}

func solidJPEG(t *testing.T, width, height int) []byte {
	t.Helper()
	img := image.NewNRGBA(image.Rect(0, 0, width, height))
	for y := 0; y < height; y++ {
		for x := 0; x < width; x++ {
			img.Set(x, y, color.NRGBA{R: 140, G: 90, B: 30, A: 255})
		}
	}
	var out bytes.Buffer
	if err := jpeg.Encode(&out, img, &jpeg.Options{Quality: 90}); err != nil {
		t.Fatal(err)
	}
	return out.Bytes()
}

type recordedImageUpload struct {
	key         string
	contentType string
	body        []byte
}

type recordingImageBlob struct {
	mu      sync.Mutex
	calls   int
	failAt  int
	uploads []recordedImageUpload
	deletes []string
}

func (b *recordingImageBlob) Enabled() bool { return true }

func (b *recordingImageBlob) Upload(_ context.Context, object blob.FileUpload) (string, error) {
	b.mu.Lock()
	defer b.mu.Unlock()
	b.calls++
	if b.failAt > 0 && b.calls == b.failAt {
		return "", errors.New("injected upload failure")
	}
	body, err := io.ReadAll(object.Body)
	if err != nil {
		return "", err
	}
	b.uploads = append(b.uploads, recordedImageUpload{
		key:         object.Key,
		contentType: object.ContentType,
		body:        body,
	})
	return "https://cdn.example/" + object.Key, nil
}

func (b *recordingImageBlob) Delete(_ context.Context, key string) error {
	b.mu.Lock()
	defer b.mu.Unlock()
	b.deletes = append(b.deletes, key)
	return nil
}

func (b *recordingImageBlob) uploadCount() int {
	b.mu.Lock()
	defer b.mu.Unlock()
	return len(b.uploads)
}

func (b *recordingImageBlob) deletedKeys() []string {
	b.mu.Lock()
	defer b.mu.Unlock()
	return append([]string(nil), b.deletes...)
}

func (b *recordingImageBlob) wasDeleted(key string) bool {
	for _, deleted := range b.deletedKeys() {
		if deleted == key {
			return true
		}
	}
	return false
}

type failingCreatePostStore struct {
	store.Store
}

func (f *failingCreatePostStore) CreatePost(context.Context, *store.Post) error {
	return errors.New("injected store failure")
}