package tgapi

import (
	"context"
	"errors"
	"fmt"
	"io"
	"mime"
	"mime/multipart"
	"net/http"
	"strings"
	"testing"
)

func TestUploaderEncodesJSONFieldsAndLeavesAcceptEncodingToHTTPTransport(t *testing.T) {
	var (
		gotPath           string
		gotAcceptEncoding string
		gotFields         map[string]string
		gotFileName       string
		gotFileData       []byte
		roundTripErr      error
	)

	client := &http.Client{
		Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
			gotPath = req.URL.Path
			gotAcceptEncoding = req.Header.Get("Accept-Encoding")

			gotFields, gotFileName, gotFileData, roundTripErr = readMultipartRequest(req)
			if roundTripErr != nil {
				roundTripErr = fmt.Errorf("readMultipartRequest: %w", roundTripErr)
			}

			return &http.Response{
				StatusCode: http.StatusOK,
				Header:     http.Header{"Content-Type": []string{"application/json"}},
				Body:       io.NopCloser(strings.NewReader(`{"ok":true,"result":{"message_id":5,"date":1}}`)),
			}, nil
		}),
	}

	api := NewAPI(
		NewAPIOpts("token").
			SetAPIURL("https://example.test").
			SetHTTPClient(client),
	)
	defer func() {
		if err := api.Close(); err != nil {
			t.Fatalf("Close returned error: %v", err)
		}
	}()

	uploader := NewUploader(api)
	defer func() {
		if err := uploader.Close(); err != nil {
			t.Fatalf("Close returned error: %v", err)
		}
	}()

	msg, err := uploader.SendPhoto(
		UploadPhoto{
			ChatID: 42,
			CaptionEntities: []MessageEntity{{
				Type:   MessageEntityBold,
				Offset: 0,
				Length: 4,
			}},
			ReplyMarkup: &ReplyMarkup{
				InlineKeyboard: [][]InlineKeyboardButton{{
					{Text: "A", CallbackData: "b"},
				}},
			},
		},
		NewUploaderFile("photo.jpg", []byte("img")),
	)
	if err != nil {
		t.Fatalf("SendPhoto returned error: %v", err)
	}
	if msg.MessageID != 5 {
		t.Fatalf("unexpected message id: %d", msg.MessageID)
	}
	if roundTripErr != nil {
		t.Fatalf("multipart parse failed: %v", roundTripErr)
	}
	if gotPath != "/bottoken/sendPhoto" {
		t.Fatalf("unexpected request path: %s", gotPath)
	}
	if gotAcceptEncoding != "" {
		t.Fatalf("expected empty Accept-Encoding header, got %q", gotAcceptEncoding)
	}
	if got := gotFields["chat_id"]; got != "42" {
		t.Fatalf("chat_id mismatch: %q", got)
	}
	if got := gotFields["caption_entities"]; got != `[{"type":"bold","offset":0,"length":4}]` {
		t.Fatalf("caption_entities mismatch: %q", got)
	}
	if got := gotFields["reply_markup"]; got != `{"inline_keyboard":[[{"text":"A","callback_data":"b"}]]}` {
		t.Fatalf("reply_markup mismatch: %q", got)
	}
	if gotFileName != "photo.jpg" {
		t.Fatalf("unexpected file name: %q", gotFileName)
	}
	if string(gotFileData) != "img" {
		t.Fatalf("unexpected file content: %q", string(gotFileData))
	}
}

func TestUploaderRejectsDirectRichMessageDraftUpload(t *testing.T) {
	uploader := &Uploader{}
	_, err := uploader.SendRichMessageDraft(
		SendRichMessageDraft{ChatID: 42, DraftID: 1},
		NewUploaderFile("photo.jpg", []byte("photo")),
	)
	if !errors.Is(err, ErrRichMessageDraftUploadUnsupported) {
		t.Fatalf("expected ErrRichMessageDraftUploadUnsupported, got %v", err)
	}
}

func TestUploaderSurfacesResponseErrorForTelegramFailure(t *testing.T) {
	const responseBody = `{"ok":false,"error_code":400,"description":"Bad Request: chat not found"}`

	client := &http.Client{
		Transport: roundTripFunc(func(_ *http.Request) (*http.Response, error) {
			return &http.Response{
				StatusCode: http.StatusOK,
				Header:     http.Header{"Content-Type": []string{"application/json"}},
				Body:       io.NopCloser(strings.NewReader(responseBody)),
			}, nil
		}),
	}

	api := NewAPI(
		NewAPIOpts("token").
			SetAPIURL("https://example.test").
			SetHTTPClient(client),
	)
	defer func() {
		if err := api.Close(); err != nil {
			t.Fatalf("Close returned error: %v", err)
		}
	}()

	uploader := NewUploader(api)
	defer func() {
		if err := uploader.Close(); err != nil {
			t.Fatalf("Close returned error: %v", err)
		}
	}()

	_, err := uploader.SendPhoto(
		UploadPhoto{ChatID: 42},
		NewUploaderFile("photo.jpg", []byte("img")),
	)
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	var respErr *ResponseError
	if !errors.As(err, &respErr) {
		t.Fatalf("expected *ResponseError, got %T: %v", err, err)
	}
	if respErr.Code != 400 {
		t.Fatalf("unexpected ResponseError.Code: got %d want 400", respErr.Code)
	}
	if !strings.Contains(respErr.Description, "chat not found") {
		t.Fatalf("unexpected ResponseError.Description: %q", respErr.Description)
	}
}

func TestNewUploaderFileDetectsFileTypeCaseInsensitively(t *testing.T) {
	tests := []struct {
		name     string
		filename string
		want     UploaderFileType
	}{
		{name: "uppercase photo", filename: "PHOTO.JPG", want: UploaderPhotoType},
		{name: "uppercase voice", filename: "voice.OGG", want: UploaderVoiceType},
		{name: "unknown defaults to document", filename: "archive.BIN", want: UploaderDocumentType},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			file := NewUploaderFile(tt.filename, []byte("x"))
			if file.field != tt.want {
				t.Fatalf("unexpected uploader field: got %q want %q", file.field, tt.want)
			}
		})
	}
}

func TestUploaderSendLivePhotoUsesRequiredMultipartFields(t *testing.T) {
	tests := []struct {
		name string
		send func(*Uploader) (Message, error)
	}{
		{
			name: "background context",
			send: func(uploader *Uploader) (Message, error) {
				return uploader.SendLivePhoto(
					UploadLivePhoto{ChatID: 42},
					NewUploaderFile("live.mp4", []byte("video")),
					NewUploaderFile("photo.jpg", []byte("image")),
				)
			},
		},
		{
			name: "explicit context",
			send: func(uploader *Uploader) (Message, error) {
				return uploader.SendLivePhotoWithContext(
					context.Background(),
					UploadLivePhoto{ChatID: 42},
					NewUploaderFile("live.mp4", []byte("video")),
					NewUploaderFile("photo.jpg", []byte("image")),
				)
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			var (
				gotPath  string
				gotFiles map[string]multipartFile
				parseErr error
			)
			client := &http.Client{
				Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
					gotPath = req.URL.Path
					gotFiles, parseErr = readMultipartFiles(req)
					return &http.Response{
						StatusCode: http.StatusOK,
						Header:     http.Header{"Content-Type": []string{"application/json"}},
						Body:       io.NopCloser(strings.NewReader(`{"ok":true,"result":{"message_id":5,"date":1}}`)),
					}, nil
				}),
			}
			api := NewAPI(
				NewAPIOpts("token").
					SetAPIURL("https://example.test").
					SetHTTPClient(client),
			)
			defer func() {
				if err := api.Close(); err != nil {
					t.Errorf("Close API returned error: %v", err)
				}
			}()
			uploader := NewUploader(api)
			defer func() {
				if err := uploader.Close(); err != nil {
					t.Errorf("Close uploader returned error: %v", err)
				}
			}()

			if _, err := tt.send(uploader); err != nil {
				t.Fatalf("SendLivePhoto returned error: %v", err)
			}
			if parseErr != nil {
				t.Fatalf("multipart parse failed: %v", parseErr)
			}
			if gotPath != "/bottoken/sendLivePhoto" {
				t.Fatalf("unexpected request path: %q", gotPath)
			}
			assertMultipartFile(t, gotFiles, "live_photo", "live.mp4", "video")
			assertMultipartFile(t, gotFiles, "photo", "photo.jpg", "image")
		})
	}
}

func TestPrepareMultipartRichMessageUsesAttachName(t *testing.T) {
	params := SendRichMessage{
		ChatID: 42,
		RichMessage: InputRichMessage{Blocks: []InputRichBlock{
			InputRichBlockAnimation{
				Type:      InputRichTypeAnimation,
				Animation: InputMedia{Type: InputMediaTypeAnimation, Media: "attach://animation"},
			},
		}},
	}

	buf, contentType, err := prepareMultipart(
		[]UploaderFile{NewUploaderFile("animation.mp4", []byte("animation")).SetAttachName("animation")},
		params,
	)
	if err != nil {
		t.Fatalf("prepareMultipart returned error: %v", err)
	}

	_, contentTypeParams, err := mime.ParseMediaType(contentType)
	if err != nil {
		t.Fatalf("ParseMediaType returned error: %v", err)
	}
	reader := multipart.NewReader(buf, contentTypeParams["boundary"])

	parts := make(map[string]string)
	var fileData []byte
	for {
		part, err := reader.NextPart()
		if err == io.EOF {
			break
		}
		if err != nil {
			t.Fatalf("NextPart returned error: %v", err)
		}
		data, err := io.ReadAll(part)
		if err != nil {
			t.Fatalf("ReadAll returned error: %v", err)
		}
		if part.FileName() != "" {
			if part.FormName() != "animation" {
				t.Errorf("file form name = %q, want animation", part.FormName())
			}
			fileData = data
			continue
		}
		parts[part.FormName()] = string(data)
	}

	if string(fileData) != "animation" {
		t.Errorf("file data = %q, want animation", fileData)
	}
	if got := parts["rich_message"]; !strings.Contains(got, `"media":"attach://animation"`) {
		t.Errorf("rich_message = %s, want attach reference", got)
	}
}

func readMultipartRequest(req *http.Request) (map[string]string, string, []byte, error) {
	_, params, err := mime.ParseMediaType(req.Header.Get("Content-Type"))
	if err != nil {
		return nil, "", nil, err
	}
	reader := multipart.NewReader(req.Body, params["boundary"])

	fields := make(map[string]string)
	var fileName string
	var fileData []byte
	for {
		part, err := reader.NextPart()
		if err == io.EOF {
			return fields, fileName, fileData, nil
		}
		if err != nil {
			return nil, "", nil, err
		}

		data, err := io.ReadAll(part)
		if err != nil {
			return nil, "", nil, err
		}

		if part.FileName() != "" {
			fileName = part.FileName()
			fileData = data
			continue
		}
		fields[part.FormName()] = string(data)
	}
}

type multipartFile struct {
	name string
	data string
}

func readMultipartFiles(req *http.Request) (map[string]multipartFile, error) {
	_, params, err := mime.ParseMediaType(req.Header.Get("Content-Type"))
	if err != nil {
		return nil, err
	}
	reader := multipart.NewReader(req.Body, params["boundary"])
	files := make(map[string]multipartFile)
	for {
		part, err := reader.NextPart()
		if err == io.EOF {
			return files, nil
		}
		if err != nil {
			return nil, err
		}
		if part.FileName() == "" {
			continue
		}
		data, err := io.ReadAll(part)
		if err != nil {
			return nil, err
		}
		files[part.FormName()] = multipartFile{name: part.FileName(), data: string(data)}
	}
}

func assertMultipartFile(t *testing.T, files map[string]multipartFile, field, name, data string) {
	t.Helper()
	file, ok := files[field]
	if !ok {
		t.Fatalf("multipart field %q is missing", field)
	}
	if file.name != name {
		t.Errorf("multipart field %q filename = %q, want %q", field, file.name, name)
	}
	if file.data != data {
		t.Errorf("multipart field %q data = %q, want %q", field, file.data, data)
	}
}