package server

import (
	"crypto/rand"
	"encoding/hex"
	"encoding/json"
	"io"
	"net/http"
)

type AuthProvider interface {
	ProviderName() string
	ProviderID() *string
	ProviderType() string
}

type AuthProviderBase struct {
	Name string  `json:"name"`
	ID   *string `json:"id"`
	Type string  `json:"type"`
}

func (bp *AuthProviderBase) ProviderName() string { return bp.Name }
func (bp *AuthProviderBase) ProviderID() *string  { return bp.ID }
func (bp *AuthProviderBase) ProviderType() string { return bp.Type }

type LocalProvider struct {
	AuthProviderBase
}

var HomeAssistant = "homeassistant"

func hassProvider() *LocalProvider {
	return &LocalProvider{
		AuthProviderBase: AuthProviderBase{
			Name: "Home Assistant Local",
			Type: HomeAssistant,
		},
	}
}

// TODO: make this configurable
func (s *Server) providersHandler(w http.ResponseWriter, r *http.Request) {
	providers := []AuthProvider{
		hassProvider(),
	}

	rjs, err := json.Marshal(providers)
	if err != nil {
		panic(err)
	}

	logRequest(http.StatusOK, r)

	w.Header()["Content-Type"] = []string{"application/json"}
	_, err = w.Write(rjs)
	if err != nil {
		panic(err)
	}
}

func (s *Server) authorizeHandler(w http.ResponseWriter, r *http.Request) {
	authPage, err := s.rootFS.Open("authorize.html")
	if err != nil {
		panic(err)
	}
	defer authPage.Close()

	logRequest(http.StatusOK, r)

	_, err = io.Copy(w, authPage)
	if err != nil {
		panic(err)
	}
}

type flowRequest struct {
	ClientID    string    `json:"client_id"`
	Handler     []*string `json:"handler"`
	RedirectURI string    `json:"redirect_uri"`
}

type FlowSchemaItem struct {
	Type     string `json:"type"`
	Name     string `json:"name"`
	Required bool   `json:"required"`
}

type FlowType string

const (
	TypeForm FlowType = "form"
)

type FlowID string
type Step string

const (
	StepInit Step = "init"
)

type flowResponse struct {
	Type      FlowType         `json:"type"`
	ID        FlowID           `json:"flow_id"`
	Handler   []*string        `json:"handler"`
	StepID    Step             `json:"step_id"`
	Schema    []FlowSchemaItem `json:"data_schema"`
	Errors    []string         `json:"errors"`
	DescPlace *string          `json:"description_placeholders"`
	LastStep  *string          `json:"last_step"`
}

func GenFlowID() FlowID {
	b := make([]byte, 16)
	if _, err := rand.Read(b); err != nil {
		panic(err)
	}

	return FlowID(hex.EncodeToString(b))
}

func (s *Server) loginFlowHandler(w http.ResponseWriter, r *http.Request) {
	var flowReq flowRequest
	err := json.NewDecoder(r.Body).Decode(&flowReq)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)

		return
	}

	resp := flowResponse{
		Type:   TypeForm,
		ID:     GenFlowID(),
		StepID: StepInit,
		Schema: []FlowSchemaItem{
			{
				Type:     "string",
				Name:     "username",
				Required: true,
			},
			{
				Type:     "string",
				Name:     "password",
				Required: true,
			},
		},
		Handler: []*string{
			&HomeAssistant,
			nil,
		},
		Errors: []string{},
	}

	w.Header()["Content-Type"] = []string{"application/json"}

	respByte, err := json.Marshal(&resp)
	_, err = w.Write(respByte)
	if err != nil {
		panic(err)
	}
}