package test

import (
	"bytes"
	"crypto/sha256"
	"encoding/base64"
	"encoding/hex"
	"image"
	"image/color"
	"image/jpeg"
	"image/png"
	"io"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"testing"
)

const webpFixtureBase64 = "UklGRhoAAABXRUJQVlA4TA0AAAAvAAAAEAcQERGIiP4HAA=="

const svgFixture = `<svg xmlns="http://www.w3.org/2000/svg" width="10" height="10"/>`

func solidImage(width int, height int) image.Image {
	canvas := image.NewRGBA(image.Rect(0, 0, width, height))
	for x := 0; x < width; x++ {
		for y := 0; y < height; y++ {
			canvas.Set(x, y, color.RGBA{R: uint8(x * 40), G: uint8(y * 40), B: 200, A: 255})
		}
	}
	return canvas
}

func pngBytes(t *testing.T, width int, height int) []byte {
	t.Helper()
	buffer := &bytes.Buffer{}
	if err := png.Encode(buffer, solidImage(width, height)); err != nil {
		t.Fatalf("failed to encode png: %v", err)
	}
	return buffer.Bytes()
}

func jpegBytes(t *testing.T, width int, height int) []byte {
	t.Helper()
	buffer := &bytes.Buffer{}
	if err := jpeg.Encode(buffer, solidImage(width, height), nil); err != nil {
		t.Fatalf("failed to encode jpeg: %v", err)
	}
	return buffer.Bytes()
}

func webpBytes(t *testing.T) []byte {
	t.Helper()
	data, err := base64.StdEncoding.DecodeString(webpFixtureBase64)
	if err != nil {
		t.Fatalf("failed to decode webp fixture: %v", err)
	}
	return data
}

func paddedPngBytes(t *testing.T, size int) []byte {
	t.Helper()
	data := pngBytes(t, 3, 2)
	return append(data, bytes.Repeat([]byte{0}, size-len(data))...)
}

func sha256Hex(data []byte) string {
	sum := sha256.Sum256(data)
	return hex.EncodeToString(sum[:])
}

func newMultipartFileRequest(t *testing.T, method string, url string, filename string, contentType string, content []byte) *http.Request {
	t.Helper()
	body := &bytes.Buffer{}
	writer := multipart.NewWriter(body)
	part, err := writer.CreatePart(map[string][]string{
		"Content-Disposition": {`form-data; name="file"; filename="` + filename + `"`},
		"Content-Type":        {contentType},
	})
	if err != nil {
		t.Fatalf("failed to create multipart part: %v", err)
	}
	if _, err := io.Copy(part, bytes.NewReader(content)); err != nil {
		t.Fatalf("failed to write file content: %v", err)
	}
	if err := writer.Close(); err != nil {
		t.Fatalf("failed to close multipart writer: %v", err)
	}
	req := httptest.NewRequest(method, url, body)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	return req
}

func newMultipartWithoutFileRequest(t *testing.T, url string) *http.Request {
	t.Helper()
	body := &bytes.Buffer{}
	writer := multipart.NewWriter(body)
	if err := writer.Close(); err != nil {
		t.Fatalf("failed to close multipart writer: %v", err)
	}
	req := httptest.NewRequest(http.MethodPost, url, body)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	return req
}