// Copyright © 2015-2017 Daniele Tricoli <eriol@mornie.org>.
// All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main // import "eriol.xyz/piken"

import (
	"encoding/csv"
	"io"
	"net/http"
	"os"
	"strconv"
	"time"

	"github.com/Sirupsen/logrus"
	"github.com/cheggaaa/pb"
	"github.com/mitchellh/go-homedir"
)

// Get Last-Modified for resources with the given URL.
func checkLastModified(url string) (time.Time, error) {
	r, err := http.Head(url)
	if err != nil {
		return time.Unix(0, 0), err
	}
	defer r.Body.Close()

	t, err := time.Parse(time.RFC1123, r.Header["Last-Modified"][0])
	if err != nil {
		return time.Unix(0, 0), err
	}

	return t, nil

}

// Download a file from URL `url` and save to `output`.
// A progress bar is showed during the download.
func download(url, output string) error {

	r, err := http.Get(url)
	if err != nil {
		return err
	}
	defer r.Body.Close()

	out, err := os.Create(output)
	if err != nil {
		return err
	}
	defer out.Close()

	size, _ := strconv.Atoi(r.Header.Get("Content-Length"))

	bar := pb.New(size).SetUnits(pb.U_BYTES).SetRefreshRate(time.Millisecond * 10)
	bar.ShowSpeed = true
	bar.Start()

	writer := io.MultiWriter(out, bar)

	// io.copyBuffer, the actual implementation of io.Copy, reads maximum 32 KB
	// from input, writes to output and then repeats. No need to worry about
	// the size of file to download.
	_, err = io.Copy(writer, r.Body)
	if err != nil {
		return err
	}

	bar.Finish()
	return nil
}

// Get user home directory or exit with a fatal error.
func getHome() string {

	homeDir, err := homedir.Dir()
	if err != nil {
		logrus.Fatal(err)
	}

	return homeDir
}

// Read a CSV file and return a slice of slice.
func readCsvFile(filepath string) (records [][]string, err error) {

	file, err := os.Open(filepath)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	reader := csv.NewReader(file)
	reader.Comma = ';'
	records, err = reader.ReadAll()
	if err != nil {
		return nil, err
	}

	return records, nil
}