// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package zip

import (
	"bytes"
	"encoding/binary"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
	"testing"
	"time"
)

type ZipTest struct {
	Name    string
	Source  func() (r io.ReaderAt, size int64) // if non-nil, used instead of testdata/<Name> file
	Comment string
	File    []ZipTestFile
	Error   error // the error that Opening this file should return
}

type ZipTestFile struct {
	Name       string
	Content    []byte // if blank, will attempt to compare against File
	ContentErr error
	File       string // name of file to compare to (relative to testdata/)
	Mtime      string // modified time in format "mm-dd-yy hh:mm:ss"
	Mode       os.FileMode
}

// Caution: The Mtime values found for the test files should correspond to
//          the values listed with unzip -l <zipfile>. However, the values
//          listed by unzip appear to be off by some hours. When creating
//          fresh test files and testing them, this issue is not present.
//          The test files were created in Sydney, so there might be a time
//          zone issue. The time zone information does have to be encoded
//          somewhere, because otherwise unzip -l could not provide a different
//          time from what the archive/zip package provides, but there appears
//          to be no documentation about this.

var tests = []ZipTest{
	{
		Name:    "test.zip",
		Comment: "This is a zipfile comment.",
		File: []ZipTestFile{
			{
				Name:    "test.txt",
				Content: []byte("This is a test text file.\n"),
				Mtime:   "09-05-10 12:12:02",
				Mode:    0644,
			},
			{
				Name:  "gophercolor16x16.png",
				File:  "gophercolor16x16.png",
				Mtime: "09-05-10 15:52:58",
				Mode:  0644,
			},
		},
	},
	{
		Name: "r.zip",
		File: []ZipTestFile{
			{
				Name:  "r/r.zip",
				File:  "r.zip",
				Mtime: "03-04-10 00:24:16",
				Mode:  0666,
			},
		},
	},
	{
		Name: "symlink.zip",
		File: []ZipTestFile{
			{
				Name:    "symlink",
				Content: []byte("../target"),
				Mode:    0777 | os.ModeSymlink,
			},
		},
	},
	{
		Name: "readme.zip",
	},
	{
		Name:  "readme.notzip",
		Error: ErrFormat,
	},
	{
		Name: "dd.zip",
		File: []ZipTestFile{
			{
				Name:    "filename",
				Content: []byte("This is a test textfile.\n"),
				Mtime:   "02-02-11 13:06:20",
				Mode:    0666,
			},
		},
	},
	{
		// created in windows XP file manager.
		Name: "winxp.zip",
		File: crossPlatform,
	},
	{
		// created by Zip 3.0 under Linux
		Name: "unix.zip",
		File: crossPlatform,
	},
	{
		// created by Go, before we wrote the "optional" data
		// descriptor signatures (which are required by OS X)
		Name: "go-no-datadesc-sig.zip",
		File: []ZipTestFile{
			{
				Name:    "foo.txt",
				Content: []byte("foo\n"),
				Mtime:   "03-08-12 16:59:10",
				Mode:    0644,
			},
			{
				Name:    "bar.txt",
				Content: []byte("bar\n"),
				Mtime:   "03-08-12 16:59:12",
				Mode:    0644,
			},
		},
	},
	{
		// created by Go, after we wrote the "optional" data
		// descriptor signatures (which are required by OS X)
		Name: "go-with-datadesc-sig.zip",
		File: []ZipTestFile{
			{
				Name:    "foo.txt",
				Content: []byte("foo\n"),
				Mode:    0666,
			},
			{
				Name:    "bar.txt",
				Content: []byte("bar\n"),
				Mode:    0666,
			},
		},
	},
	{
		Name:   "Bad-CRC32-in-data-descriptor",
		Source: returnCorruptCRC32Zip,
		File: []ZipTestFile{
			{
				Name:       "foo.txt",
				Content:    []byte("foo\n"),
				Mode:       0666,
				ContentErr: ErrChecksum,
			},
			{
				Name:    "bar.txt",
				Content: []byte("bar\n"),
				Mode:    0666,
			},
		},
	},
	// Tests that we verify (and accept valid) crc32s on files
	// with crc32s in their file header (not in data descriptors)
	{
		Name: "crc32-not-streamed.zip",
		File: []ZipTestFile{
			{
				Name:    "foo.txt",
				Content: []byte("foo\n"),
				Mtime:   "03-08-12 16:59:10",
				Mode:    0644,
			},
			{
				Name:    "bar.txt",
				Content: []byte("bar\n"),
				Mtime:   "03-08-12 16:59:12",
				Mode:    0644,
			},
		},
	},
	// Tests that we verify (and reject invalid) crc32s on files
	// with crc32s in their file header (not in data descriptors)
	{
		Name:   "crc32-not-streamed.zip",
		Source: returnCorruptNotStreamedZip,
		File: []ZipTestFile{
			{
				Name:       "foo.txt",
				Content:    []byte("foo\n"),
				Mtime:      "03-08-12 16:59:10",
				Mode:       0644,
				ContentErr: ErrChecksum,
			},
			{
				Name:    "bar.txt",
				Content: []byte("bar\n"),
				Mtime:   "03-08-12 16:59:12",
				Mode:    0644,
			},
		},
	},
}

var crossPlatform = []ZipTestFile{
	{
		Name:    "hello",
		Content: []byte("world \r\n"),
		Mode:    0666,
	},
	{
		Name:    "dir/bar",
		Content: []byte("foo \r\n"),
		Mode:    0666,
	},
	{
		Name:    "dir/empty/",
		Content: []byte{},
		Mode:    os.ModeDir | 0777,
	},
	{
		Name:    "readonly",
		Content: []byte("important \r\n"),
		Mode:    0444,
	},
}

func TestReader(t *testing.T) {
	for _, zt := range tests {
		readTestZip(t, zt)
	}
}

func readTestZip(t *testing.T, zt ZipTest) {
	var z *Reader
	var err error
	if zt.Source != nil {
		rat, size := zt.Source()
		z, err = NewReader(rat, size)
	} else {
		var rc *ReadCloser
		rc, err = OpenReader(filepath.Join("testdata", zt.Name))
		if err == nil {
			z = &rc.Reader
		}
	}
	if err != zt.Error {
		t.Errorf("error=%v, want %v", err, zt.Error)
		return
	}

	// bail if file is not zip
	if err == ErrFormat {
		return
	}

	// bail here if no Files expected to be tested
	// (there may actually be files in the zip, but we don't care)
	if zt.File == nil {
		return
	}

	if z.Comment != zt.Comment {
		t.Errorf("%s: comment=%q, want %q", zt.Name, z.Comment, zt.Comment)
	}
	if len(z.File) != len(zt.File) {
		t.Fatalf("%s: file count=%d, want %d", zt.Name, len(z.File), len(zt.File))
	}

	// test read of each file
	for i, ft := range zt.File {
		readTestFile(t, zt, ft, z.File[i])
	}

	// test simultaneous reads
	n := 0
	done := make(chan bool)
	for i := 0; i < 5; i++ {
		for j, ft := range zt.File {
			go func(j int, ft ZipTestFile) {
				readTestFile(t, zt, ft, z.File[j])
				done <- true
			}(j, ft)
			n++
		}
	}
	for ; n > 0; n-- {
		<-done
	}
}

func readTestFile(t *testing.T, zt ZipTest, ft ZipTestFile, f *File) {
	if f.Name != ft.Name {
		t.Errorf("%s: name=%q, want %q", zt.Name, f.Name, ft.Name)
	}

	if ft.Mtime != "" {
		mtime, err := time.Parse("01-02-06 15:04:05", ft.Mtime)
		if err != nil {
			t.Error(err)
			return
		}
		if ft := f.ModTime(); !ft.Equal(mtime) {
			t.Errorf("%s: %s: mtime=%s, want %s", zt.Name, f.Name, ft, mtime)
		}
	}

	testFileMode(t, zt.Name, f, ft.Mode)

	size0 := f.UncompressedSize

	var b bytes.Buffer
	r, err := f.Open()
	if err != nil {
		t.Error(err)
		return
	}

	if size1 := f.UncompressedSize; size0 != size1 {
		t.Errorf("file %q changed f.UncompressedSize from %d to %d", f.Name, size0, size1)
	}

	_, err = io.Copy(&b, r)
	if err != ft.ContentErr {
		t.Errorf("%s: copying contents: %v (want %v)", zt.Name, err, ft.ContentErr)
	}
	if err != nil {
		return
	}
	r.Close()

	var c []byte
	if ft.Content != nil {
		c = ft.Content
	} else if c, err = ioutil.ReadFile("testdata/" + ft.File); err != nil {
		t.Error(err)
		return
	}

	if b.Len() != len(c) {
		t.Errorf("%s: len=%d, want %d", f.Name, b.Len(), len(c))
		return
	}

	for i, b := range b.Bytes() {
		if b != c[i] {
			t.Errorf("%s: content[%d]=%q want %q", f.Name, i, b, c[i])
			return
		}
	}
}

func testFileMode(t *testing.T, zipName string, f *File, want os.FileMode) {
	mode := f.Mode()
	if want == 0 {
		t.Errorf("%s: %s mode: got %v, want none", zipName, f.Name, mode)
	} else if mode != want {
		t.Errorf("%s: %s mode: want %v, got %v", zipName, f.Name, want, mode)
	}
}

func TestInvalidFiles(t *testing.T) {
	const size = 1024 * 70 // 70kb
	b := make([]byte, size)

	// zeroes
	_, err := NewReader(bytes.NewReader(b), size)
	if err != ErrFormat {
		t.Errorf("zeroes: error=%v, want %v", err, ErrFormat)
	}

	// repeated directoryEndSignatures
	sig := make([]byte, 4)
	binary.LittleEndian.PutUint32(sig, directoryEndSignature)
	for i := 0; i < size-4; i += 4 {
		copy(b[i:i+4], sig)
	}
	_, err = NewReader(bytes.NewReader(b), size)
	if err != ErrFormat {
		t.Errorf("sigs: error=%v, want %v", err, ErrFormat)
	}
}

func messWith(fileName string, corrupter func(b []byte)) (r io.ReaderAt, size int64) {
	data, err := ioutil.ReadFile(filepath.Join("testdata", fileName))
	if err != nil {
		panic("Error reading " + fileName + ": " + err.Error())
	}
	corrupter(data)
	return bytes.NewReader(data), int64(len(data))
}

func returnCorruptCRC32Zip() (r io.ReaderAt, size int64) {
	return messWith("go-with-datadesc-sig.zip", func(b []byte) {
		// Corrupt one of the CRC32s in the data descriptor:
		b[0x2d]++
	})
}

func returnCorruptNotStreamedZip() (r io.ReaderAt, size int64) {
	return messWith("crc32-not-streamed.zip", func(b []byte) {
		// Corrupt foo.txt's final crc32 byte, in both
		// the file header and TOC. (0x7e -> 0x7f)
		b[0x11]++
		b[0x9d]++

		// TODO(bradfitz): add a new test that only corrupts
		// one of these values, and verify that that's also an
		// error. Currently, the reader code doesn't verify the
		// fileheader and TOC's crc32 match if they're both
		// non-zero and only the second line above, the TOC,
		// is what matters.
	})
}