package main

import (
	"encoding/csv"
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"strconv"
	"time"

	"git.ultraware.nl/Ultraware/util"
)

type day struct {
	Date           int `json:"valid_time_gmt"`
	AvgTemperature int `json:"temp"`
}

type data struct {
	Observations []day `json:"observations"`
}

func main() {
	from := getNextDate()
	if from.After(time.Now()) {
		fmt.Println(`Nothing to get, exiting ...`)
		os.Exit(0)
	}

	to := from.AddDate(0, 0, 21)
	if to.After(time.Now()) {
		to = time.Now()
	}

	url := `https://api.weather.com/v1/location/EHGG:9:NL/observations/historical.json?apiKey=6532d6454b8aa370768e63d6ba5a832e&units=e&startDate=` + from.Format(`20060102`) + `&endDate=` + to.Format(`20060102`)

	resp, err := http.Get(url)
	util.PanicOnErr(err)
	// f, err := os.Open(`data.json`)
	// util.PanicOnErr(err)

	var d data

	err = json.NewDecoder(resp.Body).Decode(&d)
	util.PanicOnErr(err)

	out, err := os.OpenFile(`weather.csv`, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
	util.PanicOnErr(err)

	csvout := csv.NewWriter(out)
	for _, day := range d.Observations {
		csvout.Write([]string{strconv.Itoa(day.Date), fToCString(day.AvgTemperature)})
	}
	csvout.Flush()
}

func getNextDate() time.Time {
	f, err := os.Open(`weather.csv`)
	if err != nil {
		return time.Date(2019, 11, 1, 0, 0, 0, 0, time.Local)
	}

	csvf := csv.NewReader(f)
	var last []string
	for {
		row, err := csvf.Read()
		if err != nil {
			break
		}
		last = row
	}

	u, err := strconv.ParseInt(last[0], 10, 64)
	util.PanicOnErr(err)

	t := time.Unix(u, 0)

	return t.AddDate(0, 0, 1)
}

func fToCString(temp int) string {
	return strconv.FormatFloat(float64(temp-32)/1.8, 'f', 1, 64)
}