package bundle

import (
	"bytes"
	"io"
	"os"
	"path/filepath"
	"slices"
	"strings"
	"testing"

	"github.com/open-policy-agent/opa/internal/file/archive"

	"github.com/open-policy-agent/opa/v1/loader/filter"
	"github.com/open-policy-agent/opa/v1/util/test"
)

const testReadLimit = (1024 * 1024) + 1

var archiveFiles = map[string]string{
	"/a.json":                          "a",
	"/a/b.json":                        "b",
	"/a/b/c.json":                      "c",
	"/a/b/d/data.json":                 "hello",
	"/a/c/data.yaml":                   "12",
	"/some.txt":                        "text",
	"/policy.rego":                     "package foo\n p = 1",
	"/roles/policy.rego":               "package bar\n p = 1",
	"/deeper/dir/path/than/others/foo": "bar",
}

func TestTarballLoader(t *testing.T) {

	files := map[string]string{
		"/archive.tar.gz": "",
	}

	test.WithTempFS(files, func(rootDir string) {
		tarballFile := filepath.Join(rootDir, "archive.tar.gz")
		f := testGetTarballFile(t, rootDir)

		loader := NewTarballLoaderWithBaseURL(f, tarballFile)

		defer f.Close()

		testLoader(t, loader, tarballFile, archiveFiles)
	})
}

func TestIterator(t *testing.T) {

	files := make([][2]string, 0, len(archiveFiles))
	for name, content := range archiveFiles {
		files = append(files, [2]string{name, content})
	}

	buf := archive.MustWriteTarGz(files)
	bundle, err := NewReader(buf).WithLazyLoadingMode(true).Read()
	if err != nil {
		t.Fatal(err)
	}

	iterator := NewIterator(bundle.Raw)
	fileCount := 0
	for {
		_, err := iterator.Next()
		if err != nil && err != io.EOF {
			t.Fatalf("Unexpected error: %s", err)
		} else if err == io.EOF {
			break
		}
		fileCount++
	}

	expCount := 4
	if fileCount != expCount {
		t.Fatalf("Expected to read %d files, read %d", expCount, fileCount)
	}
}

func TestIteratorOrder(t *testing.T) {

	var archFiles = map[string]string{
		"/a/b/c/data.json":     "[1,2,3]",
		"/a/b/d/e/data.json":   `e: true`,
		"/data.json":           `{"x": {"y": true}, "a": {"b": {"z": true}}}`,
		"/a/b/y/x/z/data.yaml": `foo: 1`,
		"/a/b/data.json":       "[4,5,6]",
		"/a/data.json":         "hello",
		"/policy.rego":         "package foo\n p = 1",
		"/roles/policy.rego":   "package bar\n p = 1",
	}

	files := make([][2]string, 0, len(archFiles))
	for name, content := range archFiles {
		files = append(files, [2]string{name, content})
	}

	buf := archive.MustWriteTarGz(files)
	bundle, err := NewReader(buf).WithLazyLoadingMode(true).Read()
	if err != nil {
		t.Fatal(err)
	}

	iterator := NewIterator(bundle.Raw)

	fileCount := 0
	actualDataFiles := []string{}

	for {
		i, err := iterator.Next()
		if err != nil && err != io.EOF {
			t.Fatalf("Unexpected error: %s", err)
		} else if err == io.EOF {
			break
		}
		fileCount++

		if !strings.HasSuffix(i.Path.String(), RegoExt) {
			actualDataFiles = append(actualDataFiles, i.Path.String())
		}
	}

	expCount := 8
	if fileCount != expCount {
		t.Fatalf("Expected to read %d files, read %d", expCount, fileCount)
	}

	expDataFiles := []string{"/", "/a", "/a/b", "/a/b/c", "/a/b/d/e", "/a/b/y/x/z"}

	if !slices.Equal(expDataFiles, actualDataFiles) {
		t.Fatalf("Expected data files %v but got %v", expDataFiles, actualDataFiles)
	}
}

func TestDirectoryLoader(t *testing.T) {
	test.WithTempFS(archiveFiles, func(rootDir string) {
		loader := NewDirectoryLoader(rootDir)

		testLoader(t, loader, rootDir, archiveFiles)
	})
}

func TestTarballLoaderWithMaxSizeBytesLimit(t *testing.T) {
	rootDir := t.TempDir()
	tarballFile := filepath.Join(rootDir, "archive.tar.gz")

	f := testGetTarballFile(t, rootDir)

	loader := NewTarballLoaderWithBaseURL(f, tarballFile).WithSizeLimitBytes(5)

	defer f.Close()

	_, err := loader.NextFile()
	if err == nil {
		t.Fatal("Expected error but got nil")
	}

	// Order of iteration over files in the tarball aren't necessarily in a deterministic order,
	// but luckily we have 2 files of 18 bytes. Just skip checking for the name here.
	expected := "size (18 bytes) exceeds configured size_limit_bytes (5 bytes)"

	if !strings.Contains(err.Error(), expected) {
		t.Errorf("Expected %q but got %v", expected, err)
	}
}
func TestTarballLoaderWithFilter(t *testing.T) {

	files := map[string]string{
		"/a/data.json":            `{"foo": "not-bar"}`,
		"/policy.rego":            "package foo\n p = 1",
		"/policy_test.rego":       "package foo\n test_p { p }",
		"/a/b/c/policy.rego":      "package bar\n q = 1",
		"/a/b/c/policy_test.rego": "package bar\n test_q { q }",
		"/a/.manifest":            `{"roots": ["a", "foo"]}`,
	}

	expectedFiles := map[string]string{
		"/a/data.json":       `{"foo": "not-bar"}`,
		"/policy.rego":       "package foo\n p = 1",
		"/a/b/c/policy.rego": "package bar\n q = 1",
		"/a/.manifest":       `{"roots": ["a", "foo"]}`,
	}

	gzFileIn := map[string]string{
		"/archive.tar.gz": "",
	}

	test.WithTempFS(gzFileIn, func(rootDir string) {
		tarballFile := filepath.Join(rootDir, "archive.tar.gz")
		f, err := os.Create(tarballFile)
		if err != nil {
			t.Fatalf("Unexpected error: %s", err)
		}

		gzFiles := make([][2]string, 0, len(files))
		for name, content := range files {
			gzFiles = append(gzFiles, [2]string{name, content})
		}

		_, err = f.Write(archive.MustWriteTarGz(gzFiles).Bytes())
		if err != nil {
			t.Fatalf("Unexpected error: %s", err)
		}
		f.Close()

		f, err = os.Open(tarballFile)
		if err != nil {
			t.Fatalf("Unexpected error: %s", err)
		}

		loader := NewTarballLoaderWithBaseURL(f, tarballFile).WithFilter(func(abspath string, info os.FileInfo, depth int) bool {
			return getFilter("*_test.rego", 1)(abspath, info, depth)
		})

		defer f.Close()

		testLoader(t, loader, tarballFile, expectedFiles)
	})
}

func TestTarballLoaderWithFilterDir(t *testing.T) {

	files := map[string]string{
		"/a/data.json":            `{"foo": "not-bar"}`,
		"/policy.rego":            "package foo\n p = 1",
		"/policy_test.rego":       "package foo\n test_p { p }",
		"/a/b/c/policy.rego":      "package bar\n q = 1",
		"/a/b/c/policy_test.rego": "package bar\n test_q { q }",
		"/a/.manifest":            `{"roots": ["a", "foo"]}`,
	}

	expectedFiles := map[string]string{
		"/policy.rego": "package foo\n p = 1",
	}

	gzFileIn := map[string]string{
		"/archive.tar.gz": "",
	}

	test.WithTempFS(gzFileIn, func(rootDir string) {
		tarballFile := filepath.Join(rootDir, "archive.tar.gz")
		f, err := os.Create(tarballFile)
		if err != nil {
			t.Fatalf("Unexpected error: %s", err)
		}

		gzFiles := make([][2]string, 0, len(files))
		for name, content := range files {
			gzFiles = append(gzFiles, [2]string{name, content})
		}

		_, err = f.Write(archive.MustWriteTarGz(gzFiles).Bytes())
		if err != nil {
			t.Fatalf("Unexpected error: %s", err)
		}
		f.Close()

		f, err = os.Open(tarballFile)
		if err != nil {
			t.Fatalf("Unexpected error: %s", err)
		}

		loader := NewTarballLoaderWithBaseURL(f, tarballFile).WithFilter(func(abspath string, info os.FileInfo, depth int) bool {
			return getFilter("*_test.rego", 1)(abspath, info, depth)
		})

		defer f.Close()

		tl, ok := loader.(*tarballLoader)
		if !ok {
			t.Fatal("Expected tar loader instance")
		}

		tl.skipDir = map[string]struct{}{"a": {}}

		fileCount := 0
		for {
			f, err := tl.NextFile()
			if err != nil && err != io.EOF {
				t.Fatalf("Unexpected error: %s", err)
			} else if err == io.EOF {
				break
			}

			expPath := strings.TrimPrefix(f.URL(), tarballFile)
			if f.Path() != expPath {
				t.Fatalf("Expected path to be %v but got %v", expPath, f.Path())
			}

			_, found := expectedFiles[f.Path()]
			if !found {
				t.Fatalf("Found unexpected file %s", f.Path())
			}

			fileCount++
		}

		if fileCount != len(expectedFiles) {
			t.Fatalf("Expected to read %d files, read %d", len(expectedFiles), fileCount)
		}
	})
}

func TestDirectoryLoaderWithFilter(t *testing.T) {
	files := map[string]string{
		"/a/data.json":            `{"foo": "not-bar"}`,
		"/policy.rego":            "package foo\n p = 1",
		"/policy_test.rego":       "package foo\n test_p { p }",
		"/a/b/c/policy.rego":      "package bar\n q = 1",
		"/a/b/c/policy_test.rego": "package bar\n test_q { q }",
		"/a/.manifest":            `{"roots": ["a", "foo"]}`,
	}

	expectedFiles := map[string]struct{}{
		"/a/data.json":       {},
		"/policy.rego":       {},
		"/a/b/c/policy.rego": {},
		"/a/.manifest":       {},
	}

	test.WithTempFS(files, func(rootDir string) {

		dl := NewDirectoryLoader(rootDir).WithFilter(func(abspath string, info os.FileInfo, depth int) bool {
			return getFilter("*_test.rego", 1)(abspath, info, depth)
		})

		fileCount := 0
		for {
			f, err := dl.NextFile()
			if err != nil && err != io.EOF {
				t.Fatalf("Unexpected error: %s", err)
			} else if err == io.EOF {
				break
			}

			expPath := strings.TrimPrefix(f.URL(), rootDir)
			if f.Path() != expPath {
				t.Fatalf("Expected path to be %v but got %v", expPath, f.Path())
			}

			_, found := expectedFiles[f.Path()]
			if !found {
				t.Fatalf("Found unexpected file %s", f.Path())
			}

			fileCount++
		}

		if fileCount != len(expectedFiles) {
			t.Fatalf("Expected to read %d files, read %d", len(expectedFiles), fileCount)
		}
	})
}

func TestDirectoryLoaderWithFilterDir(t *testing.T) {
	files := map[string]string{
		"/a/data.json":            `{"foo": "not-bar"}`,
		"/policy.rego":            "package foo\n p = 1",
		"/policy_test.rego":       "package foo\n test_p { p }",
		"/a/b/c/policy.rego":      "package bar\n q = 1",
		"/a/b/c/policy_test.rego": "package bar\n test_q { q }",
		"/a/.manifest":            `{"roots": ["a", "foo"]}`,
	}

	expectedFiles := map[string]struct{}{
		"/policy.rego":      {},
		"/policy_test.rego": {},
	}

	test.WithTempFS(files, func(rootDir string) {

		dl := NewDirectoryLoader(rootDir).WithFilter(func(abspath string, info os.FileInfo, depth int) bool {
			return getFilter("a", 1)(abspath, info, depth)
		})

		fileCount := 0
		for {
			f, err := dl.NextFile()
			if err != nil && err != io.EOF {
				t.Fatalf("Unexpected error: %s", err)
			} else if err == io.EOF {
				break
			}

			expPath := strings.TrimPrefix(f.URL(), rootDir)
			if f.Path() != expPath {
				t.Fatalf("Expected path to be %v but got %v", expPath, f.Path())
			}

			_, found := expectedFiles[f.Path()]
			if !found {
				t.Fatalf("Found unexpected file %s", f.Path())
			}

			fileCount++
		}

		if fileCount != len(expectedFiles) {
			t.Fatalf("Expected to read %d files, read %d", len(expectedFiles), fileCount)
		}
	})

}

func testGetTarballFile(t *testing.T, root string) *os.File {
	t.Helper()

	tarballFile := filepath.Join(root, "archive.tar.gz")
	f, err := os.Create(tarballFile)
	if err != nil {
		t.Fatalf("Unexpected error: %s", err)
	}

	gzFiles := make([][2]string, 0, len(archiveFiles))
	for name, content := range archiveFiles {
		gzFiles = append(gzFiles, [2]string{name, content})
	}

	_, err = f.Write(archive.MustWriteTarGz(gzFiles).Bytes())
	if err != nil {
		t.Fatalf("Unexpected error: %s", err)
	}
	f.Close()

	f, err = os.Open(tarballFile)
	if err != nil {
		t.Fatalf("Unexpected error: %s", err)
	}

	return f
}

func testLoader(t *testing.T, loader DirectoryLoader, baseURL string, expectedFiles map[string]string) {
	t.Helper()

	fileCount := 0
	for {
		f, err := loader.NextFile()
		if err != nil && err != io.EOF {
			t.Fatalf("Unexpected error: %s", err)
		} else if err == io.EOF {
			break
		}

		expPath := strings.TrimPrefix(f.URL(), baseURL)
		if f.Path() != expPath {
			t.Fatalf("Expected path to be %v but got %v", expPath, f.Path())
		}

		var buf bytes.Buffer
		n, err := f.Read(&buf, testReadLimit)
		f.Close() // always close, even on error
		if err != nil && err != io.EOF {
			t.Fatalf("Unexpected error: %s", err)
		} else if err == nil && n >= testReadLimit {
			t.Fatalf("Attempted to read too much data")
		}

		expectedContent, found := expectedFiles[f.Path()]
		if !found {
			t.Fatalf("Found unexpected file %s", f.Path())
		}
		if expectedContent != buf.String() {
			t.Fatalf("Content mismatch for file %s\n\nExpected:\n%s\n\nActual:\n%s\n\n",
				f.Path(), expectedContent, buf.String())
		}

		fileCount++
	}

	if fileCount != len(expectedFiles) {
		t.Fatalf("Expected to read %d files, read %d", len(expectedFiles), fileCount)
	}
}

func TestNewDirectoryLoaderNormalizedRoot(t *testing.T) {
	cases := []struct {
		note     string
		root     string
		expected string
	}{
		{
			note:     "abs",
			root:     "/a/b/c",
			expected: "/a/b/c",
		},
		{
			note:     "trailing slash",
			root:     "/a/b/c/",
			expected: "/a/b/c/",
		},
		{
			note:     "empty",
			root:     "",
			expected: "",
		},
		{
			note:     "single abs",
			root:     "/",
			expected: "/",
		},
		{
			note:     "single relative",
			root:     "foo",
			expected: "foo",
		},
		{
			note:     "single relative dot",
			root:     ".",
			expected: ".",
		},
		{
			note:     "single relative dot slash",
			root:     "./",
			expected: ".",
		},
		{
			note:     "relative leading dot slash",
			root:     "./a/b/c",
			expected: "a/b/c",
		},
		{
			note:     "relative",
			root:     "a/b/c",
			expected: "a/b/c",
		},
	}

	for _, tc := range cases {
		t.Run(tc.note, func(t *testing.T) {
			l := NewDirectoryLoader(tc.root)
			actual := l.(*dirLoader).root
			if actual != tc.expected {
				t.Fatalf("Expected root %s got %s", tc.expected, actual)
			}
		})
	}
}

func getFilter(pattern string, minDepth int) filter.LoaderFilter {
	return func(_ string, info os.FileInfo, depth int) bool {
		match, _ := filepath.Match(pattern, info.Name())
		return match && depth >= minDepth
	}
}
