package api

import (
	"encoding/json"
	"io"
	"net/http"
	"path"
	"strconv"
	"strings"
	"time"

	"git.t-juice.club/torjus/gpaste"
	"git.t-juice.club/torjus/gpaste/files"
	"git.t-juice.club/torjus/gpaste/users"
	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	"github.com/google/uuid"
	"go.uber.org/zap"
)

type HTTPServer struct {
	Files        files.FileStore
	Users        users.UserStore
	Auth         *gpaste.AuthService
	config       *gpaste.ServerConfig
	Logger       *zap.SugaredLogger
	AccessLogger *zap.SugaredLogger
	http.Server
}

func NewHTTPServer(cfg *gpaste.ServerConfig) *HTTPServer {
	srv := &HTTPServer{
		config:       cfg,
		Logger:       zap.NewNop().Sugar(),
		AccessLogger: zap.NewNop().Sugar(),
	}
	srv.Files = files.NewMemoryFileStore()
	srv.Users = users.NewMemoryUserStore()
	srv.Auth = gpaste.NewAuthService(srv.Users, []byte(srv.config.SigningSecret))

	// Create initial user
	// TODO: Do properly
	user := &users.User{Username: "admin", Role: users.RoleAdmin}
	user.SetPassword("admin")
	srv.Users.Store(user)

	r := chi.NewRouter()
	r.Use(middleware.RealIP)
	r.Use(middleware.RequestID)
	r.Use(srv.MiddlewareAccessLogger)
	r.Use(srv.MiddlewareAuthentication)
	r.Get("/", srv.HandlerIndex)
	r.Post("/api/file", srv.HandlerAPIFilePost)
	r.Get("/api/file/{id}", srv.HandlerAPIFileGet)
	r.Delete("/api/file/{id}", srv.HandlerAPIFileDelete)
	r.Post("/api/login", srv.HandlerAPILogin)
	r.Post("/api/user", srv.HandlerAPIUserCreate)
	srv.Handler = r

	return srv
}

func (s *HTTPServer) HandlerIndex(w http.ResponseWriter, r *http.Request) {
	_, _ = w.Write([]byte("index"))
}

func (s *HTTPServer) HandlerAPIFilePost(w http.ResponseWriter, r *http.Request) {
	reqID := middleware.GetReqID(r.Context())

	// Check if multipart form
	ct := r.Header.Get("Content-Type")
	if strings.Contains(ct, "multipart/form-data") {
		s.processMultiPartFormUpload(w, r)
		return
	}

	f := fileFromParams(r)
	f.ID = uuid.NewString()
	f.Body = r.Body

	err := s.Files.Store(f)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		s.Logger.Warnw("Error storing file.", "req_id", reqID, "error", err, "id", f.ID, "remote_addr", r.RemoteAddr)
		return
	}
	s.Logger.Infow("Stored file.", "req_id", reqID, "id", f.ID, "remote_addr", r.RemoteAddr)
	fileURL := path.Join(s.config.URL, "/api/file", f.ID)
	var resp = struct {
		Message string `json:"message"`
		ID      string `json:"id"`
		URL     string `json:"url"`
	}{
		Message: "OK",
		ID:      f.ID,
		URL:     fileURL,
	}
	w.WriteHeader(http.StatusAccepted)
	encoder := json.NewEncoder(w)
	if err := encoder.Encode(&resp); err != nil {
		s.Logger.Warnw("Error encoding response to client.", "req_id", reqID, "error", err, "remote_addr", r.RemoteAddr)
	}
}

func (s *HTTPServer) HandlerAPIFileGet(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if id == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	f, err := s.Files.Get(id)
	if err != nil {
		// TODO: LOG
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	w.WriteHeader(http.StatusOK)
	if _, err := io.Copy(w, f.Body); err != nil {
		reqID := middleware.GetReqID(r.Context())
		s.Logger.Warnw("Error writing file to client.", "req_id", reqID, "error", err, "remote_addr", r.RemoteAddr)
	}
}

func (s *HTTPServer) HandlerAPIFileDelete(w http.ResponseWriter, r *http.Request) {
	// TODO: Require auth
	id := chi.URLParam(r, "id")
	if id == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	err := s.Files.Delete(id)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	reqID := middleware.GetReqID(r.Context())
	s.Logger.Infow("Deleted file", "id", id, "req_id", reqID)
}

func (s *HTTPServer) processMultiPartFormUpload(w http.ResponseWriter, r *http.Request) {
	reqID := middleware.GetReqID(r.Context())

	var responses []ResponseAPIFilePost

	if err := r.ParseMultipartForm(1024 * 1024 * 10); err != nil {
		s.Logger.Warnw("Error parsing multipart form.", "req_id", reqID, "err", err)
	}
	for k := range r.MultipartForm.File {
		ff, fh, err := r.FormFile(k)
		if err != nil {
			s.Logger.Warnw("Error reading file from multipart form.", "req_id", reqID, "error", err)
			return
		}
		f := fileFromParams(r)
		f.ID = uuid.NewString()
		f.OriginalFilename = fh.Filename
		f.Body = ff

		if err := s.Files.Store(f); err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			s.Logger.Warnw("Error storing file.", "req_id", reqID, "error", err, "id", f.ID, "remote_addr", r.RemoteAddr)
			return
		}
		s.Logger.Infow("Stored file.", "req_id", reqID, "id", f.ID, "filename", f.OriginalFilename, "remote_addr", r.RemoteAddr)

		fileURL := path.Join(s.config.URL, "/api/file", f.ID)
		responses = append(responses, ResponseAPIFilePost{Message: "OK", ID: f.ID, URL: fileURL})

	}

	w.WriteHeader(http.StatusAccepted)
	encoder := json.NewEncoder(w)
	if err := encoder.Encode(&responses); err != nil {
		s.Logger.Warnw("Error encoding response to client.", "req_id", reqID, "error", err, "remote_addr", r.RemoteAddr)
	}
}

func (s *HTTPServer) HandlerAPILogin(w http.ResponseWriter, r *http.Request) {
	reqID := middleware.GetReqID(r.Context())
	var expectedRequest RequestAPILogin
	decoder := json.NewDecoder(r.Body)
	defer r.Body.Close()
	if err := decoder.Decode(&expectedRequest); err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	token, err := s.Auth.Login(expectedRequest.Username, expectedRequest.Password)
	if err != nil {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	response := ResponseAPILogin{
		Token: token,
	}

	s.Logger.Infow("User logged in.", "req_id", reqID, "username", expectedRequest.Username)

	encoder := json.NewEncoder(w)
	if err := encoder.Encode(&response); err != nil {
		s.Logger.Infow("Error encoding json response to client.", "req_id", reqID, "error", err, "remote_addr", r.RemoteAddr)
	}
}

func (s *HTTPServer) HandlerAPIUserCreate(w http.ResponseWriter, r *http.Request) {
	reqID := middleware.GetReqID(r.Context())
	defer r.Body.Close()

	role, err := RoleFromRequest(r)
	if err != nil || role != users.RoleAdmin {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	var req RequestAPIUserCreate
	decoder := json.NewDecoder(r.Body)
	if err := decoder.Decode(&req); err != nil {
		s.Logger.Debugw("Error parsing request.", "req_id", reqID, "error", err, "remote_addr", r.RemoteAddr)
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// TODO: Ensure user does not already exist
	user := &users.User{Username: req.Username, Role: users.RoleUser}
	if err := user.SetPassword(req.Password); err != nil {
		s.Logger.Warnw("Error setting user password.", "req_id", reqID, "error", err, "remote_addr", r.RemoteAddr)
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	if err := s.Users.Store(user); err != nil {
		s.Logger.Warnw("Error setting user password.", "req_id", reqID, "error", err, "remote_addr", r.RemoteAddr)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	w.WriteHeader(http.StatusAccepted)
	s.Logger.Infow("Created user.", "req_id", reqID, "remote_addr", r.RemoteAddr, "username", req.Username)
}

func (s *HTTPServer) HandlerAPIUserList(w http.ResponseWriter, r *http.Request) {
	reqID := middleware.GetReqID(r.Context())

	l, err := s.Users.List()
	if err != nil {
		s.Logger.Warnw("Error listing users.", "req_id", reqID, "error", err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	encoder := json.NewEncoder(w)
	if err := encoder.Encode(l); err != nil {
		s.Logger.Warnw("Error encoding response.", "req_id", "error", err)
	}
}

func fileFromParams(r *http.Request) *files.File {
	const (
		keyMaxViews  = "max_views"
		keyExpiresOn = "exp"
	)
	var f files.File

	q := r.URL.Query()

	if q.Has(keyMaxViews) {
		views, err := strconv.ParseUint(q.Get(keyMaxViews), 10, 64)
		if err == nil {
			f.MaxViews = uint(views)
		}
	}

	if q.Has(keyExpiresOn) {
		exp, err := time.Parse(time.RFC3339, q.Get(keyExpiresOn))
		if err == nil {
			f.ExpiresOn = exp
		}
	}

	return &f
}