package api

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"time"
)

type ChargerStatus struct {
	Car       int     `json:"car"`
	Frc       int     `json:"frc"`
	SessionWh float64 `json:"session_wh"`
	Amp       int     `json:"amp"`
	Soc       int     `json:"soc"` // car battery %, 0 = not reported by car
}

type goeStatus struct {
	Car int     `json:"car"`
	Frc int     `json:"frc"`
	Wh  float64 `json:"wh"`
	Amp int     `json:"amp"`
	Soc int     `json:"soc"`
}

var chargerHTTP = &http.Client{Timeout: 5 * time.Second}

func fetchChargerStatus(host string) (ChargerStatus, error) {
	url := "http://" + host + "/api/status?filter=car,frc,wh,amp,soc"
	resp, err := chargerHTTP.Get(url)
	if err != nil {
		return ChargerStatus{}, fmt.Errorf("charger unreachable: %w", err)
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return ChargerStatus{}, err
	}
	var s goeStatus
	if err := json.Unmarshal(body, &s); err != nil {
		return ChargerStatus{}, err
	}
	return ChargerStatus{Car: s.Car, Frc: s.Frc, SessionWh: s.Wh, Amp: s.Amp, Soc: s.Soc}, nil
}

func setChargerFrc(host string, frc int) error {
	url := fmt.Sprintf("http://%s/api/set?frc=%d", host, frc)
	resp, err := chargerHTTP.Get(url)
	if err != nil {
		return fmt.Errorf("charger unreachable: %w", err)
	}
	defer resp.Body.Close()
	return nil
}

func setChargerAmp(host string, amps int) error {
	url := fmt.Sprintf("http://%s/api/set?amp=%d", host, amps)
	resp, err := chargerHTTP.Get(url)
	if err != nil {
		return fmt.Errorf("charger unreachable: %w", err)
	}
	defer resp.Body.Close()
	return nil
}

// resetCharger sends rst=1 and waits for the charger to reboot.
// frc is reset to 0 by the charger firmware, so callers must re-apply mode after this.
func resetCharger(host string) error {
	url := "http://" + host + "/api/set?rst=1"
	resp, _ := chargerHTTP.Get(url) // charger may close connection before responding
	if resp != nil {
		resp.Body.Close()
	}
	time.Sleep(8 * time.Second)
	if _, err := fetchChargerStatus(host); err != nil {
		return fmt.Errorf("charger did not recover from reset: %w", err)
	}
	return nil
}

// setChargerPhases switches between 1-phase (psm=1) and 3-phase (psm=2).
// Requires phase-switching hardware in the charger.
func setChargerPhases(host string, phases int) error {
	psm := 2
	if phases == 1 {
		psm = 1
	}
	url := fmt.Sprintf("http://%s/api/set?psm=%d", host, psm)
	resp, err := chargerHTTP.Get(url)
	if err != nil {
		return fmt.Errorf("charger unreachable: %w", err)
	}
	defer resp.Body.Close()
	return nil
}