package encurl_test

import (
	"errors"
	"testing"
	"time"

	"sneak.berlin/go/pixa/internal/encurl"
	"sneak.berlin/go/pixa/internal/imgcache"
)

// Shared test fixture strings.
const (
	testSourceHost  = "cdn.example.com"
	testSourcePath  = "/images/photo.jpg"
	testSourceQuery = "v=2"
)

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

	gen, err := encurl.NewGenerator("test-signing-key-12345")
	if err != nil {
		t.Fatalf("NewGenerator() error = %v", err)
	}

	payload := &encurl.Payload{
		SourceHost:  testSourceHost,
		SourcePath:  testSourcePath,
		SourceQuery: testSourceQuery,
		Width:       800,
		Height:      600,
		Format:      imgcache.FormatWebP,
		Quality:     90,
		FitMode:     imgcache.FitContain,
		ExpiresAt:   time.Now().Add(time.Hour).Unix(),
	}

	token, err := gen.Generate(payload)
	if err != nil {
		t.Fatalf("Generate() error = %v", err)
	}

	if token == "" {
		t.Fatal("Generate() returned empty token")
	}

	parsed, err := gen.Parse(token)
	if err != nil {
		t.Fatalf("Parse() error = %v", err)
	}

	// Verify all fields
	if parsed.SourceHost != payload.SourceHost {
		t.Errorf("SourceHost = %q, want %q", parsed.SourceHost, payload.SourceHost)
	}

	if parsed.SourcePath != payload.SourcePath {
		t.Errorf("SourcePath = %q, want %q", parsed.SourcePath, payload.SourcePath)
	}

	if parsed.SourceQuery != payload.SourceQuery {
		t.Errorf("SourceQuery = %q, want %q", parsed.SourceQuery, payload.SourceQuery)
	}

	if parsed.Width != payload.Width {
		t.Errorf("Width = %d, want %d", parsed.Width, payload.Width)
	}

	if parsed.Height != payload.Height {
		t.Errorf("Height = %d, want %d", parsed.Height, payload.Height)
	}

	if parsed.Format != payload.Format {
		t.Errorf("Format = %q, want %q", parsed.Format, payload.Format)
	}

	if parsed.Quality != payload.Quality {
		t.Errorf("Quality = %d, want %d", parsed.Quality, payload.Quality)
	}

	if parsed.FitMode != payload.FitMode {
		t.Errorf("FitMode = %q, want %q", parsed.FitMode, payload.FitMode)
	}

	if parsed.ExpiresAt != payload.ExpiresAt {
		t.Errorf("ExpiresAt = %d, want %d", parsed.ExpiresAt, payload.ExpiresAt)
	}
}

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

	gen, _ := encurl.NewGenerator("test-signing-key-12345")

	payload := &encurl.Payload{
		SourceHost: testSourceHost,
		SourcePath: testSourcePath,
		ExpiresAt:  time.Now().Add(-time.Hour).Unix(), // Already expired
	}

	token, err := gen.Generate(payload)
	if err != nil {
		t.Fatalf("Generate() error = %v", err)
	}

	_, err = gen.Parse(token)
	if err == nil {
		t.Error("Parse() should fail for expired token")
	}

	if !errors.Is(err, encurl.ErrExpired) {
		t.Errorf("Parse() error = %v, want %v", err, encurl.ErrExpired)
	}
}

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

	gen, _ := encurl.NewGenerator("test-signing-key-12345")

	_, err := gen.Parse("not-a-valid-token")
	if err == nil {
		t.Error("Parse() should fail for invalid token")
	}
}

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

	gen, _ := encurl.NewGenerator("test-signing-key-12345")

	payload := &encurl.Payload{
		SourceHost: testSourceHost,
		SourcePath: testSourcePath,
		ExpiresAt:  time.Now().Add(time.Hour).Unix(),
	}

	token, _ := gen.Generate(payload)

	// Tamper with the token
	tampered := []byte(token)
	if len(tampered) > 10 {
		tampered[10] ^= 0x01
	}

	_, err := gen.Parse(string(tampered))
	if err == nil {
		t.Error("Parse() should fail for tampered token")
	}
}

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

	gen1, _ := encurl.NewGenerator("signing-key-1")
	gen2, _ := encurl.NewGenerator("signing-key-2")

	payload := &encurl.Payload{
		SourceHost: testSourceHost,
		SourcePath: testSourcePath,
		ExpiresAt:  time.Now().Add(time.Hour).Unix(),
	}

	token, _ := gen1.Generate(payload)

	_, err := gen2.Parse(token)
	if err == nil {
		t.Error("Parse() should fail with different signing key")
	}
}

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

	payload := &encurl.Payload{
		SourceHost:  testSourceHost,
		SourcePath:  testSourcePath,
		SourceQuery: testSourceQuery,
		Width:       800,
		Height:      600,
		Format:      imgcache.FormatWebP,
		Quality:     90,
		FitMode:     imgcache.FitContain,
		ExpiresAt:   time.Now().Add(time.Hour).Unix(),
	}

	req := payload.ToImageRequest()

	if req.SourceHost != payload.SourceHost {
		t.Errorf("SourceHost = %q, want %q", req.SourceHost, payload.SourceHost)
	}

	if req.SourcePath != payload.SourcePath {
		t.Errorf("SourcePath = %q, want %q", req.SourcePath, payload.SourcePath)
	}

	if req.SourceQuery != payload.SourceQuery {
		t.Errorf("SourceQuery = %q, want %q", req.SourceQuery, payload.SourceQuery)
	}

	if req.Size.Width != payload.Width {
		t.Errorf("Width = %d, want %d", req.Size.Width, payload.Width)
	}

	if req.Size.Height != payload.Height {
		t.Errorf("Height = %d, want %d", req.Size.Height, payload.Height)
	}

	if req.Format != payload.Format {
		t.Errorf("Format = %q, want %q", req.Format, payload.Format)
	}

	if req.Quality != payload.Quality {
		t.Errorf("Quality = %d, want %d", req.Quality, payload.Quality)
	}

	if req.FitMode != payload.FitMode {
		t.Errorf("FitMode = %q, want %q", req.FitMode, payload.FitMode)
	}
}

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

	// Payload with only required fields - should get defaults
	payload := &encurl.Payload{
		SourceHost: testSourceHost,
		SourcePath: testSourcePath,
		ExpiresAt:  time.Now().Add(time.Hour).Unix(),
	}

	req := payload.ToImageRequest()

	if req.Format != encurl.DefaultFormat {
		t.Errorf("Format = %q, want default %q", req.Format, encurl.DefaultFormat)
	}

	if req.Quality != encurl.DefaultQuality {
		t.Errorf("Quality = %d, want default %d", req.Quality, encurl.DefaultQuality)
	}

	if req.FitMode != encurl.DefaultFitMode {
		t.Errorf("FitMode = %q, want default %q", req.FitMode, encurl.DefaultFitMode)
	}
}

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

	req := &imgcache.ImageRequest{
		SourceHost:  testSourceHost,
		SourcePath:  testSourcePath,
		SourceQuery: testSourceQuery,
		Size:        imgcache.Size{Width: 800, Height: 600},
		Format:      imgcache.FormatWebP,
		Quality:     90,
		FitMode:     imgcache.FitContain,
	}

	expiresAt := time.Now().Add(time.Hour)
	payload := encurl.FromImageRequest(req, expiresAt)

	if payload.SourceHost != req.SourceHost {
		t.Errorf("SourceHost = %q, want %q", payload.SourceHost, req.SourceHost)
	}

	if payload.SourcePath != req.SourcePath {
		t.Errorf("SourcePath = %q, want %q", payload.SourcePath, req.SourcePath)
	}

	if payload.Width != req.Size.Width {
		t.Errorf("Width = %d, want %d", payload.Width, req.Size.Width)
	}

	if payload.ExpiresAt != expiresAt.Unix() {
		t.Errorf("ExpiresAt = %d, want %d", payload.ExpiresAt, expiresAt.Unix())
	}
}

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

	// Request with default values - payload should omit them for
	// smaller encoding
	req := &imgcache.ImageRequest{
		SourceHost: testSourceHost,
		SourcePath: testSourcePath,
		Format:     encurl.DefaultFormat,
		Quality:    encurl.DefaultQuality,
		FitMode:    encurl.DefaultFitMode,
	}

	payload := encurl.FromImageRequest(req, time.Now().Add(time.Hour))

	// These should be zero/empty because they match defaults
	if payload.Format != "" {
		t.Errorf("Format should be empty for default, got %q", payload.Format)
	}

	if payload.Quality != 0 {
		t.Errorf("Quality should be 0 for default, got %d", payload.Quality)
	}

	if payload.FitMode != "" {
		t.Errorf("FitMode should be empty for default, got %q", payload.FitMode)
	}
}

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

	gen, _ := encurl.NewGenerator("test-signing-key-12345")

	payload := &encurl.Payload{
		SourceHost: testSourceHost,
		SourcePath: testSourcePath,
		ExpiresAt:  time.Now().Add(time.Hour).Unix(),
	}

	token, _ := gen.Generate(payload)

	// Check that token only contains URL-safe characters
	for _, c := range token {
		isURLSafe := (c >= 'a' && c <= 'z') ||
			(c >= 'A' && c <= 'Z') ||
			(c >= '0' && c <= '9') ||
			c == '-' || c == '_'
		if !isURLSafe {
			t.Errorf("Token contains non-URL-safe character: %q", c)
		}
	}
}