package imgcache

import (
	"testing"
	"time"
)

func TestSigner_Sign(t *testing.T) {
	signer := NewSigner("test-secret-key")

	req := &ImageRequest{
		SourceHost:  "cdn.example.com",
		SourcePath:  "/photos/cat.jpg",
		SourceQuery: "",
		Size:        Size{Width: 800, Height: 600},
		Format:      FormatWebP,
		Expires:     time.Unix(1704067200, 0), // Fixed timestamp for reproducibility
	}

	sig1 := signer.Sign(req)
	sig2 := signer.Sign(req)

	// Same input should produce same signature
	if sig1 != sig2 {
		t.Errorf("Sign() produced different signatures for same input: %q vs %q", sig1, sig2)
	}

	// Signature should be non-empty
	if sig1 == "" {
		t.Error("Sign() produced empty signature")
	}

	// Different input should produce different signature
	req2 := &ImageRequest{
		SourceHost:  "cdn.example.com",
		SourcePath:  "/photos/dog.jpg", // Different path
		SourceQuery: "",
		Size:        Size{Width: 800, Height: 600},
		Format:      FormatWebP,
		Expires:     time.Unix(1704067200, 0),
	}

	sig3 := signer.Sign(req2)
	if sig1 == sig3 {
		t.Error("Sign() produced same signature for different input")
	}
}

func TestSigner_Verify(t *testing.T) {
	signer := NewSigner("test-secret-key")

	tests := []struct {
		name    string
		setup   func() *ImageRequest
		wantErr error
	}{
		{
			name: "valid signature",
			setup: func() *ImageRequest {
				req := &ImageRequest{
					SourceHost: "cdn.example.com",
					SourcePath: "/photos/cat.jpg",
					Size:       Size{Width: 800, Height: 600},
					Format:     FormatWebP,
					Expires:    time.Now().Add(1 * time.Hour),
				}
				req.Signature = signer.Sign(req)

				return req
			},
			wantErr: nil,
		},
		{
			name: "expired signature",
			setup: func() *ImageRequest {
				req := &ImageRequest{
					SourceHost: "cdn.example.com",
					SourcePath: "/photos/cat.jpg",
					Size:       Size{Width: 800, Height: 600},
					Format:     FormatWebP,
					Expires:    time.Now().Add(-1 * time.Hour), // Expired
				}
				req.Signature = signer.Sign(req)

				return req
			},
			wantErr: ErrSignatureExpired,
		},
		{
			name: "invalid signature",
			setup: func() *ImageRequest {
				return &ImageRequest{
					SourceHost: "cdn.example.com",
					SourcePath: "/photos/cat.jpg",
					Size:       Size{Width: 800, Height: 600},
					Format:     FormatWebP,
					Expires:    time.Now().Add(1 * time.Hour),
					Signature:  "invalid-signature",
				}
			},
			wantErr: ErrSignatureInvalid,
		},
		{
			name: "missing expiration",
			setup: func() *ImageRequest {
				return &ImageRequest{
					SourceHost: "cdn.example.com",
					SourcePath: "/photos/cat.jpg",
					Size:       Size{Width: 800, Height: 600},
					Format:     FormatWebP,
					Signature:  "some-signature",
					// Expires is zero
				}
			},
			wantErr: ErrMissingExpiration,
		},
		{
			name: "tampered request",
			setup: func() *ImageRequest {
				req := &ImageRequest{
					SourceHost: "cdn.example.com",
					SourcePath: "/photos/cat.jpg",
					Size:       Size{Width: 800, Height: 600},
					Format:     FormatWebP,
					Expires:    time.Now().Add(1 * time.Hour),
				}
				req.Signature = signer.Sign(req)
				// Tamper with the request
				req.SourcePath = "/photos/secret.jpg"

				return req
			},
			wantErr: ErrSignatureInvalid,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req := tt.setup()
			err := signer.Verify(req)

			if tt.wantErr == nil {
				if err != nil {
					t.Errorf("Verify() unexpected error = %v", err)
				}
			} else {
				if err != tt.wantErr {
					t.Errorf("Verify() error = %v, wantErr %v", err, tt.wantErr)
				}
			}
		})
	}
}

func TestSigner_DifferentKeys(t *testing.T) {
	signer1 := NewSigner("secret-key-1")
	signer2 := NewSigner("secret-key-2")

	req := &ImageRequest{
		SourceHost: "cdn.example.com",
		SourcePath: "/photos/cat.jpg",
		Size:       Size{Width: 800, Height: 600},
		Format:     FormatWebP,
		Expires:    time.Now().Add(1 * time.Hour),
	}

	// Sign with key 1
	req.Signature = signer1.Sign(req)

	// Verify with key 1 should succeed
	if err := signer1.Verify(req); err != nil {
		t.Errorf("Verify() with same key failed: %v", err)
	}

	// Verify with key 2 should fail
	if err := signer2.Verify(req); err != ErrSignatureInvalid {
		t.Errorf("Verify() with different key should fail, got: %v", err)
	}
}

func TestGenerateSignedURL(t *testing.T) {
	signer := NewSigner("test-secret-key")

	req := &ImageRequest{
		SourceHost:  "cdn.example.com",
		SourcePath:  "/photos/cat.jpg",
		SourceQuery: "",
		Size:        Size{Width: 800, Height: 600},
		Format:      FormatWebP,
	}

	ttl := 1 * time.Hour
	path, sig, exp := signer.GenerateSignedURL(req, ttl)

	// Path should be correct format
	expectedPath := "/v1/image/cdn.example.com/photos/cat.jpg/800x600.webp"
	if path != expectedPath {
		t.Errorf("GenerateSignedURL() path = %q, want %q", path, expectedPath)
	}

	// Signature should be non-empty
	if sig == "" {
		t.Error("GenerateSignedURL() produced empty signature")
	}

	// Expiration should be approximately now + TTL
	expTime := time.Unix(exp, 0)
	expectedExp := time.Now().Add(ttl)
	if expTime.Sub(expectedExp) > time.Second {
		t.Errorf("GenerateSignedURL() exp time off by too much")
	}

	// Request should have been updated with signature and expiration
	if req.Signature != sig {
		t.Errorf("GenerateSignedURL() didn't update request signature")
	}
}

func TestGenerateSignedURL_OrigSize(t *testing.T) {
	signer := NewSigner("test-secret-key")

	req := &ImageRequest{
		SourceHost: "cdn.example.com",
		SourcePath: "/photos/cat.jpg",
		Size:       Size{Width: 0, Height: 0}, // Original size
		Format:     FormatPNG,
	}

	path, _, _ := signer.GenerateSignedURL(req, time.Hour)

	expectedPath := "/v1/image/cdn.example.com/photos/cat.jpg/orig.png"
	if path != expectedPath {
		t.Errorf("GenerateSignedURL() path = %q, want %q", path, expectedPath)
	}
}

func TestParseSignatureParams(t *testing.T) {
	tests := []struct {
		name      string
		sig       string
		expStr    string
		wantSig   string
		wantErr   bool
		checkTime bool
	}{
		{
			name:    "valid params",
			sig:     "abc123",
			expStr:  "1704067200",
			wantSig: "abc123",
			wantErr: false,
		},
		{
			name:    "empty expiration",
			sig:     "abc123",
			expStr:  "",
			wantSig: "abc123",
			wantErr: false,
		},
		{
			name:    "invalid expiration",
			sig:     "abc123",
			expStr:  "not-a-number",
			wantErr: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			sig, exp, err := ParseSignatureParams(tt.sig, tt.expStr)

			if tt.wantErr {
				if err == nil {
					t.Error("ParseSignatureParams() expected error, got nil")
				}

				return
			}

			if err != nil {
				t.Errorf("ParseSignatureParams() unexpected error = %v", err)

				return
			}

			if sig != tt.wantSig {
				t.Errorf("sig = %q, want %q", sig, tt.wantSig)
			}

			if tt.expStr != "" && exp.IsZero() {
				t.Error("exp should not be zero when expStr is provided")
			}
		})
	}
}