// 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 (
	"flag"
	"fmt"
	"log"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"time"

	"android/soong/jar"
	"android/soong/third_party/zip"
)

var (
	input     = flag.String("i", "", "zip file to read from")
	output    = flag.String("o", "", "output file")
	sortGlobs = flag.Bool("s", false, "sort matches from each glob (defaults to the order from the input zip file)")
	sortJava  = flag.Bool("j", false, "sort using jar ordering within each glob (META-INF/MANIFEST.MF first)")
	setTime   = flag.Bool("t", false, "set timestamps to 2009-01-01 00:00:00")

	staticTime = time.Date(2009, 1, 1, 0, 0, 0, 0, time.UTC)
)

func main() {
	flag.Usage = func() {
		fmt.Fprintln(os.Stderr, "usage: zip2zip -i zipfile -o zipfile [-s|-j] [-t] [filespec]...")
		flag.PrintDefaults()
		fmt.Fprintln(os.Stderr, "  filespec:")
		fmt.Fprintln(os.Stderr, "    <name>")
		fmt.Fprintln(os.Stderr, "    <in_name>:<out_name>")
		fmt.Fprintln(os.Stderr, "    <glob>:<out_dir>/")
		fmt.Fprintln(os.Stderr, "")
		fmt.Fprintln(os.Stderr, "<glob> uses the rules at https://golang.org/pkg/path/filepath/#Match")
		fmt.Fprintln(os.Stderr, "As a special exception, '**' is supported to specify all files in the input zip.")
		fmt.Fprintln(os.Stderr, "")
		fmt.Fprintln(os.Stderr, "Files will be copied with their existing compression from the input zipfile to")
		fmt.Fprintln(os.Stderr, "the output zipfile, in the order of filespec arguments.")
		fmt.Fprintln(os.Stderr, "")
		fmt.Fprintln(os.Stderr, "If no filepsec is provided all files are copied (equivalent to '**').")
	}

	flag.Parse()

	if *input == "" || *output == "" {
		flag.Usage()
		os.Exit(1)
	}

	log.SetFlags(log.Lshortfile)

	reader, err := zip.OpenReader(*input)
	if err != nil {
		log.Fatal(err)
	}
	defer reader.Close()

	output, err := os.Create(*output)
	if err != nil {
		log.Fatal(err)
	}
	defer output.Close()

	writer := zip.NewWriter(output)
	defer func() {
		err := writer.Close()
		if err != nil {
			log.Fatal(err)
		}
	}()

	if err := zip2zip(&reader.Reader, writer, *sortGlobs, *sortJava, *setTime, flag.Args()); err != nil {
		log.Fatal(err)
	}
}

type pair struct {
	*zip.File
	newName string
}

func zip2zip(reader *zip.Reader, writer *zip.Writer, sortGlobs, sortJava, setTime bool, args []string) error {
	if len(args) == 0 {
		// If no filespec is provided, default to copying everything
		args = []string{"**"}
	}
	for _, arg := range args {
		var input string
		var output string

		// Reserve escaping for future implementation, so make sure no
		// one is using \ and expecting a certain behavior.
		if strings.Contains(arg, "\\") {
			return fmt.Errorf("\\ characters are not currently supported")
		}

		args := strings.SplitN(arg, ":", 2)
		input = args[0]
		if len(args) == 2 {
			output = args[1]
		}

		matches := []pair{}
		if strings.IndexAny(input, "*?[") >= 0 {
			matchAll := input == "**"
			if !matchAll && strings.Contains(input, "**") {
				return fmt.Errorf("** is only supported on its own, not with other characters")
			}

			for _, file := range reader.File {
				match := matchAll

				if !match {
					var err error
					match, err = filepath.Match(input, file.Name)
					if err != nil {
						return err
					}
				}

				if match {
					var newName string
					if output == "" {
						newName = file.Name
					} else {
						_, name := filepath.Split(file.Name)
						newName = filepath.Join(output, name)
					}
					matches = append(matches, pair{file, newName})
				}
			}

			if sortJava {
				jarSort(matches)
			} else if sortGlobs {
				sort.SliceStable(matches, func(i, j int) bool {
					return matches[i].newName < matches[j].newName
				})
			}
		} else {
			if output == "" {
				output = input
			}
			for _, file := range reader.File {
				if input == file.Name {
					matches = append(matches, pair{file, output})
					break
				}
			}
		}

		for _, match := range matches {
			if setTime {
				match.File.SetModTime(staticTime)
			}
			if err := writer.CopyFrom(match.File, match.newName); err != nil {
				return err
			}
		}
	}

	return nil
}

func jarSort(files []pair) {
	sort.SliceStable(files, func(i, j int) bool {
		return jar.EntryNamesLess(files[i].newName, files[j].newName)
	})
}