package encurl_test

import (
	"errors"
	"testing"
	"time"

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

// 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)
	}

	req := &imagerequest.Request{
		Source: imagerequest.Source{
			Host:  testSourceHost,
			Path:  testSourcePath,
			Query: testSourceQuery,
		},
		Transform: imagerequest.Transform{
			Size:    imagerequest.Size{Width: 800, Height: 600},
			Format:  imagerequest.FormatWebP,
			Quality: 90,
			FitMode: imagerequest.FitContain,
		},
		Expires: time.Now().Add(time.Hour),
	}

	token, err := gen.Generate(req)
	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.Source.Host != req.Source.Host {
		t.Errorf("SourceHost = %q, want %q", parsed.Source.Host, req.Source.Host)
	}

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

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

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

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

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

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

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

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

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

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

	req := &imagerequest.Request{
		Source: imagerequest.Source{
			Host: testSourceHost,
			Path: testSourcePath,
		},
		Expires: time.Now().Add(-time.Hour), // Already expired
	}

	token, err := gen.Generate(req)
	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")

	req := &imagerequest.Request{
		Source: imagerequest.Source{
			Host: testSourceHost,
			Path: testSourcePath,
		},
		Expires: time.Now().Add(time.Hour),
	}

	token, _ := gen.Generate(req)

	// 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")

	req := &imagerequest.Request{
		Source: imagerequest.Source{
			Host: testSourceHost,
			Path: testSourcePath,
		},
		Expires: time.Now().Add(time.Hour),
	}

	token, _ := gen1.Generate(req)

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

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

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

	// Request with only required fields - should get defaults
	token, err := gen.Generate(&imagerequest.Request{
		Source: imagerequest.Source{
			Host: testSourceHost,
			Path: testSourcePath,
		},
		Expires: time.Now().Add(time.Hour),
	})
	if err != nil {
		t.Fatalf("Generate() error = %v", err)
	}

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

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

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

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

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

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

	req := &imagerequest.Request{
		Source: imagerequest.Source{
			Host: testSourceHost,
			Path: testSourcePath,
		},
		Expires: time.Now().Add(time.Hour),
	}

	token, _ := gen.Generate(req)

	// 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)
		}
	}
}