package hass

import (
	"net/http"

	"encoding/base64"

	"github.com/rs/zerolog/log"
	"golang.org/x/crypto/bcrypt"

	"dynatron.me/x/blasphem/pkg/auth/provider"
	"dynatron.me/x/blasphem/pkg/flow"
	"dynatron.me/x/blasphem/pkg/storage"
)

const (
	HAProviderKey = "auth_provider.homeassistant"
)

type HAUser struct {
	Password string `json:"password"`
	Username string `json:"username"`

	provider.AuthProvider `json:"-"`
}

func (hau *HAUser) UserData() provider.ProviderUser {
	return &UserData{ // strip secret
		Username: hau.Username,
	}
}

type UserData struct {
	Username string `json:"username"`
}

func (ud *UserData) UserData() provider.ProviderUser {
	return ud
}

const HomeAssistant = "homeassistant"

func (h *HAUser) ProviderUserData() interface{} { return h.UserData() }

type HomeAssistantProvider struct {
	provider.AuthProviderBase `json:"-"`
	Users                     []HAUser `json:"users"`
	userMap                   map[string]*HAUser
}

func NewHAProvider(s storage.Store) (provider.AuthProvider, error) {
	hap := &HomeAssistantProvider{
		AuthProviderBase: provider.AuthProviderBase{
			Name: "Home Assistant Local",
			Type: HomeAssistant,
		},
	}

	err := s.Get(HAProviderKey, hap)
	if err != nil {
		return hap, err
	}

	hap.userMap = make(map[string]*HAUser)

	for i, u := range hap.Users {
		hap.Users[i].AuthProvider = hap
		hap.userMap[u.Username] = &hap.Users[i]
	}

	return hap, nil
}

func (hap *HomeAssistantProvider) Lookup(pu provider.ProviderUser) provider.ProviderUser {
	u, has := hap.userMap[pu.(*HAUser).Username]
	if !has {
		return nil
	}

	return u
}

func (hap *HomeAssistantProvider) hashPass(p string) ([]byte, error) {
	return bcrypt.GenerateFromPassword([]byte(p), bcrypt.DefaultCost)
}

func (hap *HomeAssistantProvider) ValidateCreds(r *http.Request, rm map[string]interface{}) (provider.ProviderUser, bool) {
	usernameE, hasU := rm["username"]
	passwordE, hasP := rm["password"]
	username, unStr := usernameE.(string)
	password, paStr := passwordE.(string)
	if !hasU || !hasP || !unStr || !paStr || username == "" || password == "" {
		return nil, false
	}

	var found *HAUser

	const dummyHash = "$2b$12$CiuFGszHx9eNHxPuQcwBWez4CwDTOcLTX5CbOpV6gef2nYuXkY7BO"

	for _, v := range hap.Users { // iterate all to thwart timing attacks
		if v.Username == username {
			found = &v
		}
	}

	if found == nil { // one more compare to thwart timing attacks
		bcrypt.CompareHashAndPassword([]byte("foo"), []byte(dummyHash))
		return nil, false
	}

	var hash []byte
	hash, err := base64.StdEncoding.DecodeString(found.Password)
	if err != nil {
		log.Error().Err(err).Msg("b64 encode fail")
		return nil, false
	}

	err = bcrypt.CompareHashAndPassword(hash, []byte(password))
	if err == nil {
		return found, true
	}

	return nil, false
}

func (hap *HomeAssistantProvider) NewCredData() interface{} {
	return &HAUser{}
}

func (hap *HomeAssistantProvider) FlowSchema() flow.FlowSchema {
	return []flow.FlowSchemaItem{
		{
			Type:     "string",
			Name:     "username",
			Required: true,
		},
		{
			Type:     "string",
			Name:     "password",
			Required: true,
		},
	}
}

func init() {
	provider.Register(HomeAssistant, NewHAProvider)
}