package chrono

import (
	"bufio"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"time"
)

type ChronoEntry struct {
	Date, Time, Action string
}

type ParsedChronoEntry struct {
	StartTime time.Time
	Action    string
	Duration  string
}

func Chrono() {
	// Return path of an executable
	exPath, err := os.Executable()
	if err != nil {
		panic(err)
	}
	exDir := filepath.Dir(exPath)
	fmt.Println(exDir)
	// Return path of the current directory
	path, err := os.Getwd()
	if err != nil {
		panic(err)
	}
	// Join paths
	textFilePath := filepath.Join(path, "chrono.txt")
	// Read file with chrono data
	readFile, err := os.Open(textFilePath)
	if err != nil {
		panic(err)
	}
	defer readFile.Close()

	fileScanner := bufio.NewScanner(readFile)
	fileScanner.Split(bufio.ScanLines)
	var fileLines []string
	for fileScanner.Scan() {
		fileLines = append(fileLines, fileScanner.Text())
	}
	// Prepare slice for data
	parse_result := make([]ChronoEntry, 0)
	result := make([]ParsedChronoEntry, 0)
	r := regexp.MustCompile(
		`(?P<date>\d{2}\s\w*\s\d{4})\s+at\s+(?P<time>\d{2}:\d{2}):\s+(?P<action>.*)`,
	)
	// Read lines from parsed data
	for _, line := range fileLines {
		// Find matches in line
		m := r.FindStringSubmatch(line)
		// Prepare dict for storing data
		result := make(map[string]string)
		// Parsing line and appending to result
		for i, name := range r.SubexpNames() {
			if i != 0 && name != "" {
				result[name] = m[i]
			}
		}
		chrono_entry := ChronoEntry{result["date"], result["time"], result["action"]}
		parse_result = append(parse_result, chrono_entry)
	}
	for index, element := range parse_result {
		layout := "02 Jan 2006-15:04"
		timestamp := fmt.Sprintf("%s-%s", element.Date, element.Time)
		t, err := time.Parse(layout, timestamp)
		if err != nil {
			panic(err)
		}
		if index == 0 {
			k := ParsedChronoEntry{StartTime: t, Action: element.Action, Duration: "0"}
			result = append(result, k)
			continue
		} else {
			delta := t.Sub(result[index-1].StartTime)
			result[index-1].Duration = delta.String()
			if delta == time.Duration(0) {
				delta = time.Duration(time.Minute)
			}
			k := ParsedChronoEntry{t, element.Action, delta.String()}
			result = append(result, k)
		}
	}
  fmt.Println(result)
}