package user

import (
	"code.google.com/p/go.crypto/bcrypt"
	"crypto/rand"
	"database/sql"
	"fmt"
	_ "github.com/lib/pq"
)

func clear(b []byte) {
	for i := 0; i < len(b); i++ {
		b[i] = 0
	}
}

func Crypt(password []byte) ([]byte, error) {
	defer clear(password)
	return bcrypt.GenerateFromPassword(password, bcrypt.DefaultCost)
}

type User struct {
	Username    string
	db          *sql.DB
}

func UsernameExists(db *sql.DB, username string) (bool, error) {
	rows, err := db.Query("SELECT count(username) FROM users where username=$1", username)
	if err != nil {
		fmt.Println("User DB Error: ", err)
		return false, err
	}
	var count int
	rows.Next()
	rows.Scan(&count)
	return count > 0, nil
}

func GenDisposablePassword() string {
	b := make([]byte, 16)
	_, err := rand.Read(b)
	if err != nil {
		fmt.Println("user.GenDisposablePassword() error reading from urandom: ", err)
	}
	return fmt.Sprintf("%x", b)
}

func NewUserFromAuth(db *sql.DB, username, password string) *User {
	fmt.Println("NewUserFromAuth:", username, ":", password)
	rows, err := db.Query("SELECT password FROM users WHERE username = $1", username)
	if err != nil {
		fmt.Println("User DB Error: ", err)
		return nil
	}
	var hash_db string
	user := User{db: db}

	if rows.Next() {
		var pw sql.NullString
		err := rows.Scan(&user.Username, &pw)
		if err != nil {
			fmt.Println("scan err: ", err)
		}
		hash_db = pw.String
	} else {
		return nil
	}
	if err = bcrypt.CompareHashAndPassword([]byte(hash_db), []byte(password)); err == nil {
		return &user
	}
	fmt.Println("auth fail:", err)
	return nil
}

func NewUserFromUsername(db *sql.DB, username string) *User {
	rows, err := db.Query("SELECT username FROM users WHERE username=$1", username)
	if err != nil {
		fmt.Println("User DB Error: ", err)
		return nil
	}
	user := User{db: db}
	if rows.Next() {
		err = rows.Scan(&user.Username)
		if err != nil {
			fmt.Println("Scan err: ", err)
		}
	} else {
		fmt.Println("User DB Error: No user found with username ", username)
		return nil
	}
	return &user
}