package main

import (
	"bufio"
	"encoding/csv"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"os"
	"strconv"
	"time"
)

type ActivityLine struct {
	Date             time.Time
	CaloriesEstimate uint64
}

func main() {
	csvFile, _ := os.Open("heat.csv")
	reader := csv.NewReader(bufio.NewReader(csvFile))
	var length int = 17
	var days = make(map[time.Time]uint64)
	for {
		line, error := reader.Read()
		if error == io.EOF {
			break
		} else if error != nil {
			log.Fatal(error)
		}
		thisTime, error := time.Parse("2006-01-02", line[0])
		thisTime = time.Date(thisTime.Year(), thisTime.Month(), thisTime.Day(), 0, 0, 0, 0, time.Local)
		if error != nil {
			fmt.Println(error)
			break
		}
		cals, error := strconv.ParseUint(line[1], 10, 64)
		if error != nil {
			break
		}

		days[thisTime] = days[thisTime] + cals
	}
	start := time.Date(time.Now().Year()-1, time.Now().Month(), time.Now().Day(), 0, 0, 0, 0, time.Local)
	svg := "<svg width=\"960\" height=\"152\"><g transform=\"translate(29.5,24)\"><g fill=\"none\" stroke=\"#ccc\">"
	datePointer := start
	var week int = 0
	midnightThisMorning := time.Date(time.Now().Year(), time.Now().Month(), time.Now().Day(), 0, 0, 0, 0, time.Local)

	var monthChange = false
	var monthLabelSpots = make(map[string]int)
	for {

		var calsOnDay = days[datePointer]

		if calsOnDay > 0 {
			svg = fmt.Sprintf("%s\n<rect width=\"%v\" height=\"%v\" x=\"%v\" y=\"%v\" fill=\"#00FF00\"></rect>", svg, length, length, week*length, length*int(datePointer.Weekday()))
		} else {
			svg = fmt.Sprintf("%s\n<rect width=\"%v\" height=\"%v\" x=\"%v\" y=\"%v\" ></rect>", svg, length, length, week*length, length*int(datePointer.Weekday()))
		}
		datePointer = datePointer.Add(time.Hour * 24)

		if datePointer.After(midnightThisMorning) {
			break
		}
		if datePointer.Day() == 1 {
			monthChange = true
		}
		if datePointer.Weekday() == time.Sunday {
			week++
			if monthChange {
				monthLabelSpots[datePointer.Month().String()] = week * length
				monthChange = false
			}
		}
	}
	svg = fmt.Sprintf("%s\n</g></g>", svg)

	//week labels
	//tODO: parameterize
	svg = fmt.Sprintf("%s<g transform=\"translate(6, 16)\"><text x=\"0\" y=\"30\">Mon</text><text x=\"0\" y=\"64\">Wed</text><text x=\"0\" y=\"97\">Fri</text></g>", svg)

	//month labels
	svg = fmt.Sprintf("%s<g transform=\"translate(30,14)\">", svg)
	for monthName := range monthLabelSpots {
		svg = fmt.Sprintf("%s<text x=\"%v\" y=\"0\">%v</text>", svg, monthLabelSpots[monthName], monthName[:3])
	}
	svg = fmt.Sprintf("%s</g>", svg)

	svg = fmt.Sprintf("%s</svg>", svg)
	ioutil.WriteFile("heatmap.svg", []byte(svg), 0644)
}