// Copyright 2016 Google Inc. All rights reserved.
//
// 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 main

import (
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"reflect"
	"syscall"
	"testing"
)

const attr = "user.gitsha1"
const checksum = "3f75526aa8f01eea5d76cee10722195dc73676de"

func createFSTree(names []string) (string, error) {
	dir, err := ioutil.TempDir("", "")
	if err != nil {
		return dir, err
	}

	for _, f := range names {
		p := filepath.Join(dir, f)
		if err := os.MkdirAll(filepath.Dir(p), 0755); err != nil {
			return dir, err
		}
		if err := ioutil.WriteFile(p, []byte{42}, 0644); err != nil {
			return dir, err
		}
		if err := syscall.Setxattr(p, attr, []byte(checksum), 0); err != nil {
			return dir, fmt.Errorf("Setxattr: %v", err)
		}
	}
	return dir, nil
}

func TestConstruct(t *testing.T) {
	dir, err := createFSTree([]string{
		"toplevel",
		"build/core/.git/HEAD",
		"build/core/subdir/core.h",
		"build/core/song/.git/HEAD",
		"build/core/song/song.mp3",
		"build/core/top",
		"build/subfile",
	})
	if err != nil {
		t.Fatal(err)
	}
	parent := newRepoTree(dir)
	construct(dir, "", parent)

	songT := &repoTree{
		children: map[string]*repoTree{},
		entries:  []string{"song.mp3"},
	}
	coreT := &repoTree{
		children: map[string]*repoTree{"song": songT},
		entries: []string{"subdir/core.h",
			"top",
		},
	}
	topT := &repoTree{
		children: map[string]*repoTree{
			"build/core": coreT,
		},
		entries: []string{
			"build/subfile",
			"toplevel",
		},
	}

	if !reflect.DeepEqual(topT, parent) {
		t.Errorf("got %#v want %#v", parent, topT)
	}

	all := topT.allChildren()
	want := map[string]*repoTree{
		"":                topT,
		"build/core":      coreT,
		"build/core/song": songT,
	}

	if !reflect.DeepEqual(all, want) {
		t.Errorf("got %#v want %#v", all, want)
	}
}

func TestPopulate(t *testing.T) {
	dir, err := createFSTree([]string{
		"ro/toplevel",
		"ro/build/core/.gitid",
		"ro/build/core/subdir/core.h",
		"ro/build/core/song/.gitid",
		"ro/build/core/song/song.mp3",
		"ro/build/core/top",
		"ro/build/subfile",
		"ro/platform/art/.gitid",
		"ro/platform/art/art.c",
		"ro/platform/art/art.h",
		"ro/platform/art/painting/.gitid",
		"ro/platform/art/painting/picasso.c",
		"rw/build/core/.git/head",
		"rw/build/core/newdir/bla",
	})
	if err != nil {
		t.Fatal("createFSTree:", err)
	}

	if err := os.Symlink(filepath.Join(dir, "ro/obsolete"), filepath.Join(dir, "rw/obsolete")); err != nil {
		t.Errorf("Symlink: %v", err)
	}

	if err := populateCheckout(filepath.Join(dir, "ro"), filepath.Join(dir, "rw")); err != nil {
		t.Errorf("populateCheckout: %v", err)
	}

	for _, f := range []string{
		"build/core/newdir/bla",
		"build/core/song/song.mp3",
		"platform/art/art.c",
		"platform/art/art.h",
		"platform/art/painting/picasso.c",
	} {
		fn := filepath.Join(dir, "rw", f)
		fi, err := os.Stat(fn)
		if err != nil || fi.Size() != 1 {
			t.Errorf("Stat(%s): %v, %v", fn, fi, err)
		}
	}

	// The following files are in repo that has a r/w checkout, so
	// they should not appear in the populated tree.
	for _, f := range []string{
		"ro/build/core/subdir/core.h",
		"ro/build/core/top",
	} {
		fn := filepath.Join(dir, "rw", f)
		_, err := os.Stat(fn)
		if err == nil {
			t.Errorf("file %s exists", fn)
		}
	}

	if fi, err := os.Lstat(filepath.Join(dir, "rw/obsolete")); err == nil {
		t.Fatalf("obsolete symlink still there: %v", fi)
	}
}

func TestChangedFiles(t *testing.T) {
	dir, err := createFSTree([]string{
		"r1/manifest.xml",
		"r1/a",
		"r1/b",
		"r2/manifest.xml",
		"r2/a",
		"r2/b",
		"r2/c",
	})
	if err != nil {
		t.Fatalf("createFSTree: %v", err)
	}

	ck2 := "3f75526aa8f01eea5d76cee10722195dc73676df"
	for _, changed := range []string{"r2/b", "r2/manifest.xml"} {
		if err := syscall.Setxattr(filepath.Join(dir, changed), attr, []byte(ck2), 0); err != nil {
			t.Fatalf("Setxattr: %v", err)
		}
	}

	got, err := changedFiles(filepath.Join(dir, "r1"), filepath.Join(dir, "r2"))
	if err != nil {
		t.Fatalf("changedFiles: %v", err)
	}
	if want := []string{"b", "c"}; !reflect.DeepEqual(want, got) {
		t.Errorf("got %v, want %v", got, want)
	}
}

func TestClearEmptyDirs(t *testing.T) {
	dir, err := createFSTree([]string{
		"ro/build/sub/sub2/p1/.gitid",
		"ro/build/sub/sub2/p1/build.mk",

		"rw/build/proj/.git/HEAD",
		"rw/build/proj/build.mk",

		"r3/toplevel",
	})
	if err != nil {
		t.Fatal("createFSTree:", err)
	}

	dest := filepath.Join(dir, "rw", "build/sub/sub2/p1")
	if err := os.MkdirAll(filepath.Dir(dest), 0755); err != nil {
		t.Errorf("MkdirAll: %v", err)
	}
	if err := os.Symlink(filepath.Join(dir, "ro", "build/sub/sub2/p1"), dest); err != nil {
		t.Errorf("Symlink(%s): %v", dest, err)
	}

	if err := populateCheckout(filepath.Join(dir, "r3"), filepath.Join(dir, "rw")); err != nil {
		t.Errorf("populateCheckout: %v", err)
	}

	gone := filepath.Join(dir, "rw", "build", "sub")
	if fi, err := os.Lstat(gone); err == nil {
		t.Errorf("directory %s still there: %v", gone, fi)
	}
}