/*
   Copyright Docker attest authors

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package tuf

import (
	"context"
	"fmt"
	"net/http"
	"net/http/httptest"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"github.com/docker/attest/internal/test"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"github.com/theupdateframework/go-tuf/v2/metadata"
)

var (
	HTTPTUFTestDataPath = filepath.Join("..", "test", "testdata", "tuf", "test-repo")
	OCITUFTestDataPath  = filepath.Join("..", "test", "testdata", "tuf", "test-repo-oci")
)

func CreateTempDir(t *testing.T, dir, pattern string) string {
	// Create a temporary directory for output oci layout
	tempDir, err := os.MkdirTemp(dir, pattern)
	if err != nil {
		t.Fatalf("Failed to create temp directory: %v", err)
	}

	// Register a cleanup function to delete the temp directory when the test exits
	t.Cleanup(func() {
		if err := os.RemoveAll(tempDir); err != nil {
			t.Errorf("Failed to remove temp directory: %v", err)
		}
	})
	return tempDir
}

// NewTufClient creates a new TUF client.
func TestRootInit(t *testing.T) {
	tufPath := CreateTempDir(t, "", "tuf_temp")

	// Start a test HTTP server to serve data from /test/testdata/tuf/test-repo/ paths
	server := httptest.NewServer(http.FileServer(http.Dir(HTTPTUFTestDataPath)))
	defer server.Close()

	ctx := context.Background()
	regServer := test.NewLocalRegistry(ctx)
	defer regServer.Close()

	regAddr, err := url.Parse(regServer.URL)
	require.NoError(t, err)
	LoadRegistryTestData(ctx, t, regAddr, OCITUFTestDataPath)

	alwaysGoodVersionChecker := &MockVersionChecker{err: nil}
	alwaysBadVersionChecker := &MockVersionChecker{err: assert.AnError}

	testCases := []struct {
		name           string
		metadataSource string
		targetsSource  string
	}{
		{"http", server.URL + "/metadata", server.URL + "/targets"},
		{"oci", regAddr.Host + "/tuf-metadata:latest", regAddr.Host + "/tuf-targets"},
	}
	for _, tc := range testCases {
		_, err := NewClient(ctx, &ClientOptions{DockerTUFRootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker, ""})
		assert.NoErrorf(t, err, "Failed to create TUF client: %v", err)

		// recreation should work with same root
		_, err = NewClient(ctx, &ClientOptions{DockerTUFRootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker, ""})
		assert.NoErrorf(t, err, "Failed to recreate TUF client: %v", err)

		_, err = NewClient(ctx, &ClientOptions{[]byte("broken"), tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker, ""})
		assert.Errorf(t, err, "Expected error recreating TUF client with broken root: %v", err)

		_, err = NewClient(ctx, &ClientOptions{DockerTUFRootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysBadVersionChecker, ""})
		assert.Errorf(t, err, "Expected error recreating TUF client with bad version checker")

		_, err = NewClient(ctx, &ClientOptions{DockerTUFRootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker, "../.."})
		assert.Errorf(t, err, "Expected error recreating TUF client with bad path prefix")
	}
}

func TestDownloadTarget(t *testing.T) {
	tufPath := CreateTempDir(t, "", "tuf_temp")
	targetFile := "test.txt"
	delegatedRole := testRole
	delegatedTargetFile := fmt.Sprintf("%s/%s", delegatedRole, targetFile)

	// Start a test HTTP server to serve data from /test/testdata/tuf/test-repo/ paths
	server := httptest.NewServer(http.FileServer(http.Dir(HTTPTUFTestDataPath)))
	defer server.Close()

	ctx := context.Background()
	regServer := test.NewLocalRegistry(ctx)
	defer regServer.Close()

	regAddr, err := url.Parse(regServer.URL)
	require.NoError(t, err)
	LoadRegistryTestData(ctx, t, regAddr, OCITUFTestDataPath)

	alwaysGoodVersionChecker := &MockVersionChecker{err: nil}

	testCases := []struct {
		name           string
		metadataSource string
		targetsSource  string
		pathPrefix     string
	}{
		{"http", server.URL + "/metadata", server.URL + "/targets", ""},
		{"oci", regAddr.Host + "/tuf-metadata:latest", regAddr.Host + "/tuf-targets", ""},
		{"http, with path prefix", server.URL + "/metadata", server.URL + "/targets", "testing"},
		{"oci, with path prefix", regAddr.Host + "/tuf-metadata:latest", regAddr.Host + "/tuf-targets", "testing"},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			tufClient, err := NewClient(ctx, &ClientOptions{DockerTUFRootDev.Data, tufPath, tc.metadataSource, tc.targetsSource, alwaysGoodVersionChecker, tc.pathPrefix})
			require.NoErrorf(t, err, "Failed to create TUF client: %v", err)
			require.NotNil(t, tufClient.updater, "Failed to create updater")

			// get trusted tuf metadata
			trustedMetadata := tufClient.updater.GetTrustedMetadataSet()
			assert.NotNil(t, trustedMetadata, "Failed to get trusted metadata")

			// download top-level target files
			var roleName string
			if tc.pathPrefix != "" {
				// get target info for non-existent target, just to trigger a load of the delegated targets metadata
				_, err = tufClient.updater.GetTargetInfo(tc.pathPrefix + "/fakefile")
				assert.Error(t, err) // expect error for non-existent target
				roleName = tc.pathPrefix
			} else {
				roleName = metadata.TARGETS
			}
			targets := trustedMetadata.Targets[roleName].Signed.Targets
			for _, target := range targets {
				path := strings.TrimPrefix(target.Path, tufClient.pathPrefix)
				// download target files
				_, err := tufClient.DownloadTarget(path, filepath.Join(tufPath, "download"))
				assert.NoErrorf(t, err, "Failed to download target: %v", err)
			}

			if tc.pathPrefix == "" {
				// download delegated target, only if not using a path prefix
				targetInfo, err := tufClient.updater.GetTargetInfo(delegatedTargetFile)
				require.NoError(t, err)
				_, err = tufClient.DownloadTarget(targetInfo.Path, filepath.Join(tufPath, targetInfo.Path))
				assert.NoError(t, err)
			}
		})
	}
}

func TestGetEmbeddedTufRootBytes(t *testing.T) {
	dev, err := GetEmbeddedRoot("dev")
	assert.NoError(t, err)

	staging, err := GetEmbeddedRoot("staging")
	assert.NoError(t, err)
	assert.NotEqual(t, dev.Data, staging.Data)

	prod, err := GetEmbeddedRoot("prod")
	assert.NoError(t, err)
	assert.NotEqual(t, dev.Data, prod.Data)
	assert.NotEqual(t, staging.Data, prod.Data)

	def, err := GetEmbeddedRoot("")
	assert.NoError(t, err)
	assert.Equal(t, def.Data, prod.Data)

	_, err = GetEmbeddedRoot("invalid")
	assert.Error(t, err)
}