package charger

import (
	"errors"
	"fmt"
	"strconv"

	"github.com/evcc-io/evcc/api"
	"github.com/evcc-io/evcc/api/implement"
	"github.com/evcc-io/evcc/util"
	"github.com/evcc-io/evcc/util/homeassistant"
)

// HomeAssistant charger implementation
type HomeAssistant struct {
	*embed
	implement.Caps
	conn       *homeassistant.Connection
	status     string
	states     homeassistant.StatusMap
	enabled    string
	enable     string
	maxcurrent string
}

func init() {
	registry.Add("homeassistant", NewHomeAssistantFromConfig)
}

// NewHomeAssistantFromConfig creates a HomeAssistant charger from generic config
func NewHomeAssistantFromConfig(other map[string]any) (api.Charger, error) {
	var cc struct {
		embed                `mapstructure:",squash"`
		homeassistant.Config `mapstructure:",squash"`
		Status               string   // required - sensor for charge status
		StatusA              string   // optional - custom states mapped to status A
		StatusB              string   // optional - custom states mapped to status B
		StatusC              string   // optional - custom states mapped to status C
		Enabled              string   // required - sensor for enabled state
		Enable               string   // required - switch/input_boolean for enable/disable
		MaxCurrent           string   // required - number entity for setting max current
		Power                string   // optional - power sensor
		Energy               string   // optional - energy sensor
		Currents             []string // optional - current sensors for L1, L2, L3
		Voltages             []string // optional - voltage sensors for L1, L2, L3
		Phases               string   // optional - select entity for 1p/3p phase switching
	}

	if err := util.DecodeOther(other, &cc); err != nil {
		return nil, err
	}

	if cc.Status == "" {
		return nil, errors.New("missing status sensor entity")
	}
	if cc.Enabled == "" {
		return nil, errors.New("missing enabled sensor entity")
	}
	if cc.Enable == "" {
		return nil, errors.New("missing enable switch entity")
	}
	if cc.MaxCurrent == "" {
		return nil, errors.New("missing maxcurrent number entity")
	}

	states, err := homeassistant.NewStatusMap(cc.StatusA, cc.StatusB, cc.StatusC)
	if err != nil {
		return nil, err
	}

	log := util.NewLogger("ha-charger")

	conn, err := cc.Config.NewConnection(log)
	if err != nil {
		return nil, err
	}

	c := &HomeAssistant{
		embed:      &cc.embed,
		Caps:       implement.New(),
		conn:       conn,
		status:     cc.Status,
		states:     states,
		enabled:    cc.Enabled,
		enable:     cc.Enable,
		maxcurrent: cc.MaxCurrent,
	}

	if cc.Power != "" {
		implement.Has(c, implement.Meter(func() (float64, error) { return conn.GetFloatState(cc.Power) }))
	}
	if cc.Energy != "" {
		implement.Has(c, implement.MeterEnergy(func() (float64, error) { return conn.GetFloatState(cc.Energy) }))
	}

	// phase currents (optional)
	if phases, err := homeassistant.ValidatePhaseEntities(cc.Currents); len(phases) > 0 {
		implement.Has(c, implement.PhaseCurrents(func() (float64, float64, float64, error) { return conn.GetPhaseFloatStates(phases) }))
	} else if err != nil {
		return nil, fmt.Errorf("currents: %w", err)
	}

	// phase voltages (optional)
	if phases, err := homeassistant.ValidatePhaseEntities(cc.Voltages); len(phases) > 0 {
		implement.Has(c, implement.PhaseVoltages(func() (float64, float64, float64, error) { return conn.GetPhaseFloatStates(phases) }))
	} else if err != nil {
		return nil, fmt.Errorf("voltages: %w", err)
	}

	// phase switching (optional)
	if cc.Phases != "" {
		implement.Has(c, implement.PhaseSwitcher(func(phases int) error {
			return conn.CallSelectService(cc.Phases, strconv.Itoa(phases))
		}))

		implement.Has(c, implement.PhaseGetter(func() (int, error) {
			val, err := conn.GetIntState(cc.Phases)
			if err != nil {
				return 0, err
			}
			return int(val), nil
		}))
	}

	return c, nil
}

var _ api.Charger = (*HomeAssistant)(nil)

// Status implements the api.ChargeState interface
func (c *HomeAssistant) Status() (api.ChargeStatus, error) {
	return c.conn.GetChargeStatus(c.status, c.states)
}

// Enabled implements the api.Charger interface
func (c *HomeAssistant) Enabled() (bool, error) {
	return c.conn.GetBoolState(c.enabled)
}

// Enable implements the api.Charger interface
func (c *HomeAssistant) Enable(enable bool) error {
	return c.conn.CallSwitchService(c.enable, enable)
}

// MaxCurrent implements the api.Charger interface
func (c *HomeAssistant) MaxCurrent(current int64) error {
	return c.MaxCurrentMillis(float64(current))
}

var _ api.ChargerEx = (*HomeAssistant)(nil)

// MaxCurrentMillis implements the api.ChargerEx interface
func (c *HomeAssistant) MaxCurrentMillis(current float64) error {
	return c.conn.CallNumberService(c.maxcurrent, current)
}