package api

import (
	"database/sql"
	"encoding/json"
	"log"
	"net/http"
	"strings"

	"github.com/deepmap/oapi-codegen/pkg/types"
	"github.com/hhhapz/hackathon/models"
)

type UserService struct {
	userStore UserStore
}

func (us *UserService) GetMe(w http.ResponseWriter, r *http.Request, params GetMeParams) {
	u, err := us.userStore.UserByToken(r.Context(), params.Token)
	if err != nil {
		serverError(w, http.StatusUnauthorized, "Invalid token provided")
		return
	}

	writeUser(w, u)
}

func (us *UserService) ModifyUser(w http.ResponseWriter, r *http.Request, params ModifyUserParams) {
	u, err := us.userStore.UserByToken(r.Context(), params.Token)
	if err != nil {
		serverError(w, http.StatusUnauthorized, "Invalid token provided")
		return
	}

	var body ModifyUserJSONBody
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		serverError(w, http.StatusBadRequest, "Invalid JSON body for ModifyUser")
		return
	}

	u.Name = strings.TrimSpace(body.Name)
	if len(u.Name) < 3 || len(u.Name) > 30 {
		serverError(w, http.StatusUnprocessableEntity, "Name must be between 3 and 30 characters long")
		return
	}
	if !u.Teacher {
		if body.GradeLevel < 9 || body.GradeLevel > 12 {
			serverError(w, http.StatusUnprocessableEntity, "Grade Level must be between 9 and 12")
			return
		}
		u.GradeLevel = sql.NullInt64{Int64: int64(body.GradeLevel), Valid: true}
	}

	err = us.userStore.UpdateUser(r.Context(), u)
	if err != nil {
		log.Printf("Could not modify user %s: %v", u.Email, err)
		serverError(w, http.StatusInternalServerError, "Could not update user")
		return
	}

	writeUser(w, u)
}

func (us *UserService) GetUserByEmail(w http.ResponseWriter, r *http.Request, params GetUserByEmailParams) {
	u, err := us.userStore.UserByToken(r.Context(), params.Token)
	if err != nil {
		serverError(w, http.StatusUnauthorized, "Invalid token provided")
		return
	}

	email := string(params.Email)
	if u.Email == email {
		writeUser(w, u)
		return
	}

	if !u.Admin {
		log.Printf("user accessing unauthorized endpoint: %s", u.Email)
		serverError(w, http.StatusForbidden, "You are not authorized to do this")
		return
	}

	user, err := us.userStore.User(r.Context(), email)
	if err != nil {
		log.Printf("Could not fetch user(%q): %v", email, err)
		serverError(w, http.StatusNotFound, "Could not find user with the specified email")
		return
	}

	writeUser(w, user)
}

func (us *UserService) ModifyOtherUser(w http.ResponseWriter, r *http.Request, params ModifyOtherUserParams) {
	u, err := us.userStore.UserByToken(r.Context(), params.Token)
	if err != nil {
		serverError(w, http.StatusUnauthorized, "Invalid token provided")
		return
	}

	if !u.Admin {
		log.Printf("user accessing unauthorized endpoint: %s", u.Email)
		serverError(w, http.StatusForbidden, "You are not authorized to do this")
		return
	}

	user, err := us.userStore.User(r.Context(), string(params.Email))
	if err != nil {
		log.Printf("Could not fetch user(%q): %v", params.Email, err)
		serverError(w, http.StatusNotFound, "Could not find user with the specified email")
		return
	}

	var body ModifyOtherUserJSONBody
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		serverError(w, http.StatusBadRequest, "Invalid JSON body for ModifyOtherUser")
		return
	}

	user.Name = strings.TrimSpace(body.Name)
	user.Email = string(*body.NewEmail)
	user.Picture = body.Picture
	user.Teacher = body.Teacher
	user.Admin = body.Admin

	if len(user.Name) < 3 || len(user.Name) > 30 {
		serverError(w, http.StatusUnprocessableEntity, "Name must be between 3 and 30 characters long")
		return
	}
	user.GradeLevel = sql.NullInt64{}
	if !user.Teacher {
		if body.GradeLevel < 9 || body.GradeLevel > 12 {
			serverError(w, http.StatusUnprocessableEntity, "Grade Level must be between 9 and 12")
			return
		}
		user.GradeLevel = sql.NullInt64{Int64: int64(body.GradeLevel), Valid: true}
	}

	writeUser(w, user)
}

func (us *UserService) GetAllUsers(w http.ResponseWriter, r *http.Request, params GetAllUsersParams) {
	u, err := us.userStore.UserByToken(r.Context(), params.Token)
	if err != nil {
		serverError(w, http.StatusUnauthorized, "Invalid token provided")
		return
	}

	if !u.Admin {
		log.Printf("user accessing unauthorized endpoint: %s", u.Email)
		serverError(w, http.StatusForbidden, "You are not authorized to do this")
		return
	}

	users, err := us.userStore.Users(r.Context())
	if err != nil {
		log.Printf("user accessing unauthorized endpoint: %s", u.Email)
		serverError(w, http.StatusInternalServerError, "Could not fetch users")
		return
	}

	writeUsers(w, users)
}

func writeUser(w http.ResponseWriter, u *models.User) {
	var grade *int
	if u.GradeLevel.Valid {
		g := int(u.GradeLevel.Int64)
		grade = &g
	}

	w.WriteHeader(200)
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(User{
		Admin:      u.Admin,
		CreatedAt:  u.CreatedAt.Time(),
		Email:      types.Email(u.Email),
		GradeLevel: grade,
		Id:         u.ID,
		Name:       u.Name,
		Picture:    u.Picture,
		Teacher:    u.Teacher,
	})
}

func writeUsers(w http.ResponseWriter, us []*models.User) {
	var users []User

	for _, u := range us {
		var grade *int
		if u.GradeLevel.Valid {
			g := int(u.GradeLevel.Int64)
			grade = &g
		}

		users = append(users, User{
			Admin:      u.Admin,
			CreatedAt:  u.CreatedAt.Time(),
			Email:      types.Email(u.Email),
			GradeLevel: grade,
			Id:         u.ID,
			Name:       u.Name,
			Picture:    u.Picture,
			Teacher:    u.Teacher,
		})
	}

	w.WriteHeader(200)
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(users)
}