package diyanetapi

import (
	"context"
	"errors"
	"fmt"
	"time"

	"github.com/imroc/req/v3"

	"prayertimes/pkg/hijricalendar"
	"prayertimes/pkg/prayer"
)

type Provider struct {
	http *req.Client
}

func New(c *req.Client) Provider {
	return Provider{
		http: c.Clone().SetCommonBasicAuth("diyanet", "Q6Y3vYt5F3x2txPaaMF3uPgbK99EJhpM"),
	}
}

func (d Provider) GetByCoords(ctx context.Context, coords prayer.Coordinates) (prayer.TimesResult, error) {
	locationID, err := d.getLocationIDByCoords(ctx, coords)
	if err != nil {
		return prayer.TimesResult{}, fmt.Errorf("failed to resolve location by coordinates: %w", err)
	}

	result, err := d.Get(ctx, locationID)
	if err != nil {
		return prayer.TimesResult{}, fmt.Errorf("failed to get prayer times by coordinates: %w", err)
	}
	result.Location.Latitude = coords.Latitude
	result.Location.Longitude = coords.Longitude

	return result, nil
}

func (d Provider) getLocationIDByCoords(ctx context.Context, coords prayer.Coordinates) (string, error) {
	res, err := d.http.NewRequest().
		SetContext(ctx).
		SetQueryParams(map[string]string{
			"latitude":  fmt.Sprintf("%f", coords.Latitude),
			"longitude": fmt.Sprintf("%f", coords.Longitude),
		}).
		Get("https://namazvakti.diyanet.gov.tr/api/ilce/GetByCoordinat")
	if err != nil {
		return "", fmt.Errorf("failed to get location by coords: %w", err)
	}

	var response struct {
		Success      bool `json:"success"`
		ResultObject []struct {
			ID int `json:"cityID"`
		} `json:"resultObject"`
	}
	if err := res.Unmarshal(&response); err != nil {
		return "", fmt.Errorf("failed to unmarshal city response: %w", err)
	}
	if !response.Success {
		return "", fmt.Errorf("failed to get location by coordinates from upstream: %w", errors.New(res.String()))
	}
	if len(response.ResultObject) == 0 {
		return "", fmt.Errorf("failed to resolve location by coordinates: %w", errors.New("empty location result"))
	}

	return fmt.Sprintf("%d", response.ResultObject[0].ID), nil
}

func (d Provider) Get(ctx context.Context, locationID string) (prayer.TimesResult, error) {
	res, err := d.http.NewRequest().
		SetContext(ctx).
		SetQueryParam("ilceId", locationID).
		Get("https://namazvakti.diyanet.gov.tr/api/NamazVakti/Gunluk")
	if err != nil {
		return prayer.TimesResult{}, fmt.Errorf("failed to get prayer times by location id: %w", err)
	}

	result, err := d.parseResponse(res)
	if err != nil {
		return prayer.TimesResult{}, fmt.Errorf("failed to parse prayer times response: %w", err)
	}
	result.Location.ID = parseIntOrZero(locationID)

	return result, nil
}

func (d Provider) parseResponse(res *req.Response) (prayer.TimesResult, error) {
	var response struct {
		Success      bool `json:"success"`
		ResultObject struct {
			Location struct {
				ID       int    `json:"konum_Id"`
				Timezone string `json:"timezone"`
			} `json:"konum"`
			PrayerTimes []struct {
				Date        time.Time `json:"miladi_tarih_uzun_Iso8601"`
				DateIslamic string    `json:"hicri_tarih_uzun"`
				Fajr        time.Time `json:"imsak"`
				Sunrise     time.Time `json:"gunes"`
				Dhuhr       time.Time `json:"ogle"`
				Asr         time.Time `json:"ikindi"`
				Sunset      time.Time `json:"gunes_batis"`
				Maghrib     time.Time `json:"aksam"`
				Isha        time.Time `json:"yatsi"`
			} `json:"namazVakti"`
		} `json:"resultObject"`
	}
	if err := res.Unmarshal(&response); err != nil {
		return prayer.TimesResult{}, fmt.Errorf("failed to unmarshal as json: %w", err)
	}
	if !response.Success {
		return prayer.TimesResult{}, fmt.Errorf("failed to get prayer times from upstream: %w", errors.New(res.String()))
	}

	if len(response.ResultObject.PrayerTimes) == 0 {
		return prayer.TimesResult{}, nil
	}

	var times []prayer.Times
	today := time.Now().UTC().Truncate(time.Hour * 24)
	for _, pt := range response.ResultObject.PrayerTimes {
		then := pt.Date.UTC().Truncate(time.Hour * 24)
		if then.Before(today) {
			continue
		}

		times = append(times, prayer.Times{
			Date:      pt.Date.UTC(),
			DateHijri: hijricalendar.ToISODate(pt.Date.UTC()),
			Fajr:      pt.Fajr.UTC(),
			Sunrise:   pt.Sunrise.UTC(),
			Dhuhr:     pt.Dhuhr.UTC(),
			Asr:       pt.Asr.UTC(),
			Sunset:    pt.Sunset.UTC(),
			Maghrib:   pt.Maghrib.UTC(),
			Isha:      pt.Isha.UTC(),
		})
	}

	return prayer.TimesResult{
		Location: prayer.Location{
			ID:       response.ResultObject.Location.ID,
			Timezone: response.ResultObject.Location.Timezone,
		},
		Times: times,
	}, nil
}

func parseIntOrZero(value string) int {
	var out int
	_, _ = fmt.Sscanf(value, "%d", &out)
	return out
}