package homematic

import (
	"encoding/xml"
	"fmt"
	"net/http"
	"regexp"
	"strings"
	"time"

	"github.com/evcc-io/evcc/util"
	"github.com/evcc-io/evcc/util/request"
	"github.com/evcc-io/evcc/util/transport"
)

// Homematic plugable switchchannel and meterchannel charger based on CCU XML-RPC interface
// https://homematic-ip.com/sites/default/files/downloads/HM_XmlRpc_API.pdf
// https://homematic-ip.com/sites/default/files/downloads/HMIP_XmlRpc_API_Addendum.pdf

// Homematic CCU settings
type Settings struct {
	URI, Device, MeterChannel, SwitchChannel, User, Password string
	Cache                                                    time.Duration
}

// Connection is the Homematic CCU connection
type Connection struct {
	log *util.Logger
	*request.Helper
	*Settings
	meterG  util.Cacheable[MethodResponse]
	switchG util.Cacheable[MethodResponse]
}

// NewConnection creates a new Homematic device connection.
func NewConnection(uri, device, meterchannel, switchchannel, user, password string, cache time.Duration) (*Connection, error) {
	log := util.NewLogger("homematic")

	settings := &Settings{
		URI:           util.DefaultScheme(uri, "http"),
		Device:        device,
		MeterChannel:  meterchannel,
		SwitchChannel: switchchannel,
		Cache:         cache,
	}

	conn := &Connection{
		log:      log,
		Helper:   request.NewHelper(log),
		Settings: settings,
	}

	conn.Client.Transport = request.NewTripper(log, transport.Insecure())

	if user != "" {
		log.Redact(transport.BasicAuthHeader(user, password))
		conn.Client.Transport = transport.BasicAuth(user, password, conn.Client.Transport)
	}

	conn.switchG = util.ResettableCached(func() (MethodResponse, error) {
		return conn.XmlCmd("getParamset", conn.SwitchChannel, Param{CCUString: "VALUES"})
	}, conn.Cache)

	conn.meterG = util.ResettableCached(func() (MethodResponse, error) {
		return conn.XmlCmd("getParamset", conn.MeterChannel, Param{CCUString: "VALUES"})
	}, conn.Cache)

	return conn, nil
}

// Enable sets the homematic HMIP-PSM switchchannel state to true=on/false=off
func (c *Connection) Enable(enable bool) error {
	onoff := map[bool]string{true: "1", false: "0"}
	_, err := c.XmlCmd("setValue", c.SwitchChannel, Param{CCUString: "STATE"}, Param{CCUBool: onoff[enable]})
	if err == nil {
		c.switchG.Reset()
		c.meterG.Reset()
	}
	return err
}

// Enabled reads the homematic HMIP-PSM switchchannel state true=on/false=off
func (c *Connection) Enabled() (bool, error) {
	res, err := c.switchG.Get()
	return res.BoolValue("STATE"), err
}

// CurrentPower reads the homematic HMIP-PSM meterchannel power in W
func (c *Connection) CurrentPower() (float64, error) {
	res, err := c.meterG.Get()
	return res.FloatValue("POWER"), err
}

// TotalEnergy reads the homematic HMIP-PSM meterchannel energy in Wh
func (c *Connection) TotalEnergy() (float64, error) {
	res, err := c.meterG.Get()
	return res.FloatValue("ENERGY_COUNTER") / 1e3, err
}

// Currents reads the homematic HMIP-PSM meterchannel L1 current in A
func (c *Connection) Currents() (float64, float64, float64, error) {
	res, err := c.meterG.Get()
	return res.FloatValue("CURRENT") / 1e3, 0, 0, err
}

// GridCurrentPower reads the homematic HM-ES-TX-WM grid meterchannel power in W
func (c *Connection) GridCurrentPower() (float64, error) {
	res, err := c.meterG.Get()
	return res.FloatValue("IEC_POWER"), err
}

// GridTotalEnergy reads the homematic HM-ES-TX-WM grid meterchannel energy in kWh
func (c *Connection) GridTotalEnergy() (float64, error) {
	res, err := c.meterG.Get()
	return res.FloatValue("IEC_ENERGY_COUNTER"), err
}

func (c *Connection) XmlCmd(method, channel string, values ...Param) (MethodResponse, error) {
	target := fmt.Sprintf("%s:%s", c.Device, channel)
	hmc := MethodCall{
		XMLName:    xml.Name{},
		MethodName: method,
		Params:     append([]Param{{CCUString: target}}, values...),
	}

	var hmr MethodResponse
	body, err := xml.Marshal(hmc)
	if err != nil {
		return hmr, err
	}

	req, err := request.New(http.MethodPost, c.URI, strings.NewReader(xml.Header+string(body)), map[string]string{
		"Content-Type": "text/xml",
	})
	if err != nil {
		return hmr, err
	}

	res, err := c.DoBody(req)
	if err != nil {
		return hmr, err
	}

	// correct Homematic IP Legacy API (CCU port 2010) and XML-RPC-Schnittstelle (CCU port 2001) response encoding
	re := regexp.MustCompile("(?i)iso-8859-1")
	res = re.ReplaceAll(res, []byte("UTF-8"))

	if err := xml.Unmarshal(res, &hmr); err != nil {
		return hmr, err
	}

	return hmr, hmr.Error()
}