package main

import (
	"archive/tar"
	"bufio"
	"compress/gzip"
	"errors"
	"io"
	"net/http"
	"os"

	flag "github.com/spf13/pflag"
)

func main() {
	url := flag.StringP("url", "u", "", "Url to the APKINDEX.tar.gz")
	output := flag.StringP("output", "o", "index.md", "Output path")
	templateType := flag.StringP("template-type", "p", "text", "Template system to be used, options: html, text")
	templateFile := flag.StringP("template-file", "t", "text", "Template file to be used")
	flag.Parse()

	tarStream, err := fechIndex(*url)
	if err != nil {
		panic("Error fecthing the index: " + err.Error())
	}

	defer tarStream.Close()

	archive, err := gzip.NewReader(tarStream)
	if err != nil {
		panic("Error creating gzip reader: " + err.Error())
	}

	tr := tar.NewReader(archive)

	for {
		h, err := tr.Next()
		if err != nil {
			panic("Error reading next tar entry: " + err.Error())
		}

		if h.FileInfo().Name() == "APKINDEX" {
			break
		}
	}

	s := bufio.NewScanner(tr)

	entries := make([]*Entry, 0)
	lines := make([]string, 0)

	for s.Scan() {
		l := s.Text()
		if l == "" {
			entry := Parse(lines)
			entries = append(entries, entry)
			lines = make([]string, 0)
		} else {
			lines = append(lines, l)
		}
	}

	outputFile, err := getOutputFile(*output)
	if err != nil {
		panic("Error openning output file: " + err.Error())
	}

	tmpl, err := GetTemplate(*templateType, *templateFile)
	if err != nil {
		panic("Error loading template file: " + err.Error())
	}

	tmpl.Execute(outputFile, entries)
}

func getOutputFile(output string) (*os.File, error) {
	if output != "" {
		outputFile, err := os.Create(output)
		if err != nil {
			return nil, err
		}
		return outputFile, nil
	} else {
		return os.Stdout, nil
	}
}

func fechIndex(url string) (io.ReadCloser, error) {
	resp, err := http.Get(url)
	if err != nil {
		return nil, err
	}

	if resp.StatusCode != 200 {
		return nil, errors.New("Invlid response")
	}

	return resp.Body, nil
}