package rest

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"strings"
	"sync/atomic"
	"time"

	mjson "git.ali33.ru/fcg-xvii/go-tools/json"
	jwt "github.com/dgrijalva/jwt-go"
)

func NewRest(addr string, secret []byte, commands *CommandStore) *Rest {
	return &Rest{
		commands: commands,
		secret:   secret,
		addr:     addr,
	}
}

type Rest struct {
	secret   []byte
	addr     string
	opened   atomic.Bool
	server   *http.Server
	commands *CommandStore
}

func (s *Rest) TokenGenerate(m mjson.Map, expire int64) (string, error) {
	token := jwt.New(jwt.SigningMethodHS256)

	claims := token.Claims.(jwt.MapClaims)
	for key, val := range m {
		claims[key] = val
	}
	if expire > 0 {
		claims["exp"] = time.Now().Add(time.Minute * 30).Unix()
	}

	tokenString, err := token.SignedString(s.secret)
	return tokenString, err
}

// Listen start server in other goroutine
func (s *Rest) Listen(timeout time.Duration) (err error) {
	if s.opened.Swap(true) {
		return ErrAlreadyOpened
	}
	ctx, _ := context.WithTimeout(context.Background(), timeout)
	go func() {
		mux := http.NewServeMux()
		mux.HandleFunc("/", s.handle)
		s.server = &http.Server{
			Addr:    s.addr,
			Handler: mux,
		}
		err = s.server.ListenAndServe()
		s.opened.Store(false)
	}()
	<-ctx.Done()
	return
}

// Close
func (s *Rest) Close() error {
	if !s.opened.Load() {
		return ErrNotOpened
	}
	return s.server.Close()
}

func responseNotFound(w http.ResponseWriter) {
	w.WriteHeader(404)
}

func responseError(w http.ResponseWriter, err error, code int) {
	w.WriteHeader(code)
	w.Write([]byte(err.Error()))
}

// handle
func (s *Rest) handle(w http.ResponseWriter, r *http.Request) {
	log.Println("handle", r.URL.Path)
	// Инициализация restRequest
	rr := &Request{
		Request:        r,
		data:           mjson.Map{},
		files:          make(map[string]io.ReadCloser),
		tokenGenerator: s.TokenGenerate,
	}

	// Парсим Bearer токен и извлекаем claims
	authHeader := r.Header.Get("Authorization")
	if authHeader != "" {
		if parts := strings.Split(authHeader, " "); len(parts) == 2 && parts[0] == "Bearer" {
			tokenString := parts[1]
			token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
				if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
					return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
				}
				return s.secret, nil
			})

			if err != nil {
				log.Printf("Failed to parse JWT: %s", err)
				http.Error(w, "Invalid token", http.StatusUnauthorized)
				return
			}

			if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
				rr.auth = mjson.Map(claims)
			}
		}
	}

	// Если это многокомпонентный запрос, обрабатываем файлы
	if strings.Index(r.Header.Get("Content-Type"), "multipart/form-data") == 0 {
		err := r.ParseMultipartForm(32 << 20) // max memory 32MB, после этого файлы будут сохранены во временных файлах
		if err != nil {
			responseError(w, fmt.Errorf("failed to parse multipart form: %w", err), 500)
			return
		}
		multiPartForm := r.MultipartForm

		data, check := multiPartForm.Value["data"]
		if check {
			err := json.NewDecoder(bytes.NewBuffer([]byte(data[0]))).Decode(&rr.data)
			if err != nil {
				responseError(w, fmt.Errorf("failed to decode JSON: %w", err), 500)
				return
			}
		}

		for filename, headers := range multiPartForm.File {
			for _, header := range headers {
				file, err := header.Open()
				if err != nil {
					responseError(w, fmt.Errorf("failed to open file %s: %w", filename, err), 500)
				}
				rr.files[filename] = file
			}
		}
		defer rr.Close()
	} else {
		err := json.NewDecoder(r.Body).Decode(&rr.data)
		if err != nil {
			responseError(w, fmt.Errorf("failed to decode JSON: %w", err), 500)
			return
		}
	}

	// get command
	command, check := s.commands.GetCommand(r.URL.Path)
	if !check {
		responseNotFound(w)
		return
	}

	// validate
	resp := command.Validate(rr)
	if resp != nil {
		if err := resp.Send(w); err != nil {
			responseError(w, err, 500)
		}
		return
	}

	// execute
	resp = command.Execute(rr)
	if err := resp.Send(w); err != nil {
		responseError(w, err, 500)
	}
	resp.Close()
}