package controllers

import (
	"encoding/json"
	"errors"
	"math"
	"net/http"
	"strconv"

	"git.cromer.cl/Proyecto-Titulo/alai-server/backend/database"
	"git.cromer.cl/Proyecto-Titulo/alai-server/backend/models"
	"git.cromer.cl/Proyecto-Titulo/alai-server/backend/utils"

	"github.com/julienschmidt/httprouter"
)

func Login(writer http.ResponseWriter, request *http.Request, params httprouter.Params) {
	gdb := database.Connect()
	defer database.Close(gdb)

	var receivedUser models.User
	var user models.User

	decoder := json.NewDecoder(request.Body)

	err := decoder.Decode(&receivedUser)
	if err != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, err.Error())
		return
	}

	result := gdb.Model(models.User{}).Where(&models.User{Username: receivedUser.Username}).Find(&user)
	if result.Error != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, result.Error.Error())
		return
	} else if result.RowsAffected == 0 {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, errors.New("incorrect user or password").Error())
		return
	}

	err = user.CheckPassword(receivedUser.Password)
	if err != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, errors.New("incorrect user or password").Error())
		return
	}

	type Token struct {
		Token string `json:"token"`
	}

	tokenString, err := utils.GenerateJWT(user.Email, user.Username)
	if err != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, err.Error())
		return
	}

	token := Token{Token: tokenString}

	writer.Header().Set("Content-Type", "application/json")
	writer.WriteHeader(http.StatusOK)
	json.NewEncoder(writer).Encode(token)
}

func AuthenticateUser(writer http.ResponseWriter, request *http.Request, params httprouter.Params) {
	writer.Header().Set("Content-Type", "application/json")
	writer.WriteHeader(http.StatusNoContent)
}

func ListUser(writer http.ResponseWriter, request *http.Request, params httprouter.Params) {
	gdb := database.Connect()
	defer database.Close(gdb)

	var users []models.User

	queryParams := request.URL.Query()

	limit := 50
	if queryParams.Get("limit") != "" {
		var err error
		limit, err = strconv.Atoi(queryParams.Get("limit"))
		if err != nil {
			utils.JSONErrorOutput(writer, http.StatusBadRequest, err.Error())
			return
		}
		limit = int(math.Min(float64(500), float64(limit)))
		limit = int(math.Max(float64(1), float64(limit)))
	}

	offset := 0
	if queryParams.Get("offset") != "" {
		var err error
		offset, err = strconv.Atoi(queryParams.Get("offset"))
		if err != nil {
			utils.JSONErrorOutput(writer, http.StatusBadRequest, err.Error())
			return
		}
		offset = int(math.Min(float64(9223372036854775807), float64(offset)))
		offset = int(math.Max(float64(0), float64(offset)))
	}

	result := gdb.Model(&models.User{}).Order("ID asc").Limit(limit).Offset(offset).Find(&users)
	if result.Error != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, result.Error.Error())
		return
	} else {
		for i := range users {
			users[i].Password = ""
		}
		writer.Header().Set("Content-Type", "application/json")
		writer.WriteHeader(http.StatusOK)
		json.NewEncoder(writer).Encode(users)
	}
}

func GetUser(writer http.ResponseWriter, request *http.Request, params httprouter.Params) {
	gdb := database.Connect()
	defer database.Close(gdb)

	var user models.User

	result := gdb.Model(&models.User{}).Find(&user, params.ByName("id"))
	if result.Error != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, result.Error.Error())
		return
	} else if result.RowsAffected == 0 {
		writer.WriteHeader(http.StatusNotFound)
		return
	} else {
		user.Password = ""
		writer.Header().Set("Content-Type", "application/json")
		writer.WriteHeader(http.StatusOK)
		json.NewEncoder(writer).Encode(user)
	}
}

func CreateUser(writer http.ResponseWriter, request *http.Request, params httprouter.Params) {
	gdb := database.Connect()
	defer database.Close(gdb)

	var user models.User

	decoder := json.NewDecoder(request.Body)

	err := decoder.Decode(&user)
	if err != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, err.Error())
		return
	}

	user.HashPassword(user.Password)

	result := gdb.Create(&user)
	if result.Error != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, result.Error.Error())
		return
	} else {
		writer.WriteHeader(http.StatusNoContent)
	}
}

func UpdateUser(writer http.ResponseWriter, request *http.Request, params httprouter.Params) {
	gdb := database.Connect()
	defer database.Close(gdb)

	var user models.User

	decoder := json.NewDecoder(request.Body)

	err := decoder.Decode(&user)
	if err != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, err.Error())
		return
	}

	user.ID, err = strconv.ParseUint(params.ByName("id"), 10, 64)
	if err != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, err.Error())
		return
	}

	if user.Password != "" {
		user.HashPassword(user.Password)
	}

	result := gdb.Updates(&user)
	if result.Error != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, result.Error.Error())
		return
	} else if result.RowsAffected == 0 {
		writer.WriteHeader(http.StatusNotFound)
		return
	} else {
		writer.WriteHeader(http.StatusNoContent)
	}
}

func DeleteUser(writer http.ResponseWriter, request *http.Request, params httprouter.Params) {
	gdb := database.Connect()
	defer database.Close(gdb)

	var user models.User
	user.ID, _ = strconv.ParseUint(params.ByName("id"), 10, 64)

	result := gdb.Delete(&user)
	if result.Error != nil {
		utils.JSONErrorOutput(writer, http.StatusBadRequest, result.Error.Error())
		return
	} else if result.RowsAffected == 0 {
		writer.WriteHeader(http.StatusNotFound)
		return
	} else {
		writer.WriteHeader(http.StatusNoContent)
	}
}