package goscrobble

import (
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"net"
	"os"
	"strings"
	"time"

	"golang.org/x/crypto/bcrypt"
)

const bCryptCost = 16

type User struct {
	UUID       string    `json:"uuid"`
	CreatedAt  time.Time `json:"created_at"`
	CreatedIp  net.IP    `json:"created_ip"`
	ModifiedAt time.Time `json:"modified_at"`
	ModifiedIP net.IP    `jsos:"modified_ip"`
	Username   string    `json:"username"`
	Password   []byte    `json:"password"`
	Email      string    `json:"email"`
	Verified   bool      `json:"verified"`
	Active     bool      `json:"active"`
	Admin      bool      `json:"admin"`
	Mod        bool      `json:"mod"`
	Timezone   string    `json:"timezone"`
	Token      string    `json:"token"`
}

type UserResponse struct {
	UUID            string    `json:"uuid"`
	CreatedAt       time.Time `json:"created_at"`
	CreatedIp       net.IP    `json:"created_ip"`
	ModifiedAt      time.Time `json:"modified_at"`
	ModifiedIP      net.IP    `jsos:"modified_ip"`
	Username        string    `json:"username"`
	Email           string    `json:"email"`
	Verified        bool      `json:"verified"`
	SpotifyUsername string    `json:"spotify_username"`
	Timezone        string    `json:"timezone"`
	Token           string    `json:"token"`
	NavidromeURL    string    `json:"navidrome_server"`
}

// createUser - Called from API
func createUser(req *RequestRequest, ip net.IP) error {
	// Check if user already exists..
	if len(req.Password) < 8 {
		return errors.New("Password must be at least 8 characters")
	}

	// Check Username is set
	if req.Username == "" {
		return errors.New("A username is required")
	}

	// Check username is valid
	if !isUsernameValid(req.Username) {
		return errors.New("Username contains invalid characters")
	}

	// If set an email.. validate it!
	if req.Email != "" {
		if !isEmailValid(req.Email) {
			return errors.New("Invalid email address")
		}
	}

	// Check if user or email exists!
	if userAlreadyExists(req) {
		return errors.New("Username or email already exists")
	}

	// Lets hashit!
	hash, err := hashPassword(req.Password)
	if err != nil {
		return err
	}

	return insertUser(req.Username, req.Email, hash, ip)
}

func loginUser(logReq *RequestRequest, ip net.IP) ([]byte, error) {
	var resp []byte
	var user User

	if logReq.Username == "" {
		return resp, errors.New("A username is required")
	}

	if logReq.Password == "" {
		return resp, errors.New("A password is required")
	}

	if strings.Contains(logReq.Username, "@") {
		err := db.QueryRow(`SELECT uuid, username, email, password, admin, mod FROM users WHERE email = $1 AND active = true`,
			logReq.Username).Scan(&user.UUID, &user.Username, &user.Email, &user.Password, &user.Admin, &user.Mod)
		if err != nil {
			if err == sql.ErrNoRows {
				return resp, errors.New("Invalid Username or Password")
			}
		}
	} else {
		err := db.QueryRow(`SELECT uuid, username, email, password, admin, mod FROM users WHERE username = $1 AND active = true`,
			logReq.Username).Scan(&user.UUID, &user.Username, &user.Email, &user.Password, &user.Admin, &user.Mod)
		if err == sql.ErrNoRows {
			return resp, errors.New("Invalid Username or Password")
		}
	}

	if !isValidPassword(logReq.Password, user) {
		return resp, errors.New("Invalid Username or Password")
	}

	// Issue JWT + Response
	token, err := generateJWTToken(user, "")
	if err != nil {
		log.Printf("Error generating JWT: %v", err)
		return resp, errors.New("Error logging in")
	}

	loginResp := RequestResponse{
		Token: token,
	}

	resp, _ = json.Marshal(&loginResp)
	return resp, nil
}

// insertUser - Does the dirtywork!
func insertUser(username string, email string, password []byte, ip net.IP) error {
	token := generateToken(32)
	uuid := newUUID()

	log.Printf(ip.String())

	_, err := db.Exec(`INSERT INTO users (uuid, created_at, created_ip, modified_at, modified_ip, username, email, password, token) `+
		`VALUES ($1,NOW(),$2,NOW(),$3,$4,$5,$6,$7)`, uuid, ip.String(), ip.String(), username, email, password, token)

	return err
}

func (user *User) updateUser(field string, value string, ip net.IP) error {
	_, err := db.Exec(`UPDATE users SET "`+field+`" = $1, modified_at = NOW(), modified_ip = $2 WHERE uuid = $3`, value, ip, user.UUID)

	return err
}

func (user *User) updateUserDirect(field string, value string) error {
	_, err := db.Exec(`UPDATE users SET "`+field+`" = $1 WHERE uuid = $2`, value, user.UUID)

	return err
}

// hashPassword - Returns bcrypt hash
func hashPassword(password string) ([]byte, error) {
	return bcrypt.GenerateFromPassword([]byte(password), bCryptCost)
}

// isValidPassword - Checks if password is valid
func isValidPassword(password string, user User) bool {
	err := bcrypt.CompareHashAndPassword(user.Password, []byte(password))
	if err != nil {
		return false
	}

	return true
}

// userAlreadyExists - Returns bool indicating if a record exists for either username or email
// Using two look ups to make use of DB indexes.
func userAlreadyExists(req *RequestRequest) bool {
	count, err := getDbCount(`SELECT COUNT(*) FROM users WHERE username = $1`, req.Username)
	if err != nil {
		fmt.Printf("Error querying for duplicate users: %v", err)
		return true
	}

	if count > 0 {
		return true
	}

	if req.Email != "" {
		// Only run email check if there's an email...
		count, err = getDbCount(`SELECT COUNT(*) FROM users WHERE email = $1`, req.Email)
	}

	if err != nil {
		fmt.Printf("Error querying for duplicate users: %v", err)
		return true
	}

	return count > 0
}

func getUserByUUID(uuid string) (User, error) {
	var user User
	err := db.QueryRow(`SELECT uuid, created_at, created_ip, modified_at, modified_ip, username, email, password, verified, admin, mod, timezone, token FROM users WHERE uuid = $1 AND active = true`,
		uuid).Scan(&user.UUID, &user.CreatedAt, &user.CreatedIp, &user.ModifiedAt, &user.ModifiedIP, &user.Username, &user.Email, &user.Password, &user.Verified, &user.Admin, &user.Mod, &user.Timezone, &user.Token)

	if err == sql.ErrNoRows {
		return user, errors.New("Invalid JWT Token")
	}

	return user, nil
}

func getUserByUsername(username string) (User, error) {
	var user User
	err := db.QueryRow(`SELECT uuid, created_at, created_ip, modified_at, modified_ip, username, email, password, verified, admin, mod, timezone, token FROM users WHERE username = $1 AND active = true`,
		username).Scan(&user.UUID, &user.CreatedAt, &user.CreatedIp, &user.ModifiedAt, &user.ModifiedIP, &user.Username, &user.Email, &user.Password, &user.Verified, &user.Admin, &user.Mod, &user.Timezone, &user.Token)

	if err == sql.ErrNoRows {
		return user, errors.New("Invalid Username")
	}

	return user, nil
}

func getUserByEmail(email string) (User, error) {
	var user User
	err := db.QueryRow(`SELECT uuid, created_at, created_ip, modified_at, modified_ip, username, email, password, verified, admin, mod, timezone, token FROM users WHERE email = $1 AND active = true`,
		email).Scan(&user.UUID, &user.CreatedAt, &user.CreatedIp, &user.ModifiedAt, &user.ModifiedIP, &user.Username, &user.Email, &user.Password, &user.Verified, &user.Admin, &user.Mod, &user.Timezone, &user.Token)

	if err == sql.ErrNoRows {
		return user, errors.New("Invalid Email")
	}

	return user, nil
}

func getUserByResetToken(token string) (User, error) {
	var user User
	err := db.QueryRow(`SELECT users.uuid, created_at, created_ip, modified_at, modified_ip, username, email, password, verified, admin, mod, timezone, token FROM users `+
		`JOIN resettoken ON resettoken.user = users.uuid WHERE resettoken.token = $1 AND active = true`,
		token).Scan(&user.UUID, &user.CreatedAt, &user.CreatedIp, &user.ModifiedAt, &user.ModifiedIP, &user.Username, &user.Email, &user.Password, &user.Verified, &user.Admin, &user.Mod, &user.Timezone, &user.Token)

	if err == sql.ErrNoRows {
		return user, errors.New("Invalid Token")
	}

	return user, nil
}

func (user *User) sendResetEmail(ip net.IP) error {
	token := generateToken(16)

	// 1 hour validation
	exp := time.Now().Add(time.Hour * time.Duration(1))
	err := user.saveResetToken(token, exp)

	if err != nil {
		return err
	}

	content := fmt.Sprintf(
		"Someone at %s has request a password reset for %s.\n"+
			"Click the following link to reset your password: %s/reset/%s\n\n"+
			"This is link is valid for 1 hour",
		ip, user.Username, os.Getenv("GOSCROBBLE_DOMAIN"), token)

	return sendEmail(user.Username, user.Email, "GoScrobble - Password Reset", content)
}

func (user *User) saveResetToken(token string, expiry time.Time) error {
	_, _ = db.Exec(`DELETE FROM resettoken WHERE "user" = $1`, user.UUID)
	_, err := db.Exec(`INSERT INTO resettoken ("user", token, expiry) `+
		`VALUES ($1,$2,$3)`, user.UUID, token, expiry)

	return err
}

func clearOldResetTokens() {
	_, _ = db.Exec(`DELETE FROM resettoken WHERE expiry < NOW()`)
}

func clearResetToken(token string) error {
	_, err := db.Exec(`DELETE FROM resettoken WHERE token = $1`, token)

	return err
}

// checkResetToken - If a token exists check it
func checkResetToken(token string) (bool, error) {
	count, err := getDbCount(`SELECT COUNT(*) FROM resettoken WHERE token = $1`, token)

	if err != nil {
		return false, err
	}

	return count > 0, nil
}

func (user *User) updatePassword(newPassword string, ip net.IP) error {
	hash, err := hashPassword(newPassword)
	if err != nil {
		return errors.New("Bad password")
	}

	_, err = db.Exec(`UPDATE users SET password = $1 WHERE uuid = $2`, hash, user.UUID)
	if err != nil {
		return errors.New("Failed to update password")
	}

	return nil
}

func (user *User) getSpotifyTokens() (OauthToken, error) {
	return getOauthToken(user.UUID, "spotify")
}

func (user *User) getNavidromeTokens() (OauthToken, error) {
	return getOauthToken(user.UUID, "navidrome")
}

func getAllSpotifyUsers() ([]User, error) {
	users := make([]User, 0)
	rows, err := db.Query(`SELECT users.uuid, created_at, created_ip, modified_at, modified_ip, users.username, email, password, verified, admin, mod, timezone FROM users ` +
		`JOIN oauth_tokens ON oauth_tokens."user" = users.uuid AND oauth_tokens.service = 'spotify' WHERE users.active = true`)

	if err != nil {
		log.Printf("Failed to fetch spotify users: %+v", err)
		return users, errors.New("Failed to fetch configs")
	}

	defer rows.Close()

	for rows.Next() {
		var user User
		err := rows.Scan(&user.UUID, &user.CreatedAt, &user.CreatedIp, &user.ModifiedAt, &user.ModifiedIP, &user.Username, &user.Email, &user.Password, &user.Verified, &user.Admin, &user.Mod, &user.Timezone)
		if err != nil {
			log.Printf("Failed to fetch spotify user: %+v", err)
			return users, errors.New("Failed to fetch users")
		}

		users = append(users, user)
	}

	err = rows.Err()
	if err != nil {
		log.Printf("Failed to fetch spotify users: %+v", err)
		return users, errors.New("Failed to fetch users")
	}

	return users, nil
}

func getAllNavidromeUsers() ([]User, error) {
	users := make([]User, 0)
	rows, err := db.Query(`SELECT users.uuid, created_at, created_ip, modified_at, modified_ip, users.username, email, password, verified, admin, mod, timezone FROM users ` +
		`JOIN oauth_tokens ON oauth_tokens."user" = users.uuid AND oauth_tokens.service = 'navidrome' WHERE users.active = true`)

	if err != nil {
		log.Printf("Failed to fetch navidrome users: %+v", err)
		return users, errors.New("Failed to fetch configs")
	}

	defer rows.Close()

	for rows.Next() {
		var user User
		err := rows.Scan(&user.UUID, &user.CreatedAt, &user.CreatedIp, &user.ModifiedAt, &user.ModifiedIP, &user.Username, &user.Email, &user.Password, &user.Verified, &user.Admin, &user.Mod, &user.Timezone)
		if err != nil {
			log.Printf("Failed to fetch navidrome user: %+v", err)
			return users, errors.New("Failed to fetch users")
		}

		users = append(users, user)
	}

	err = rows.Err()
	if err != nil {
		log.Printf("Failed to fetch navidrome users: %+v", err)
		return users, errors.New("Failed to fetch users")
	}

	return users, nil
}