package auth

import (
	"crypto/rand"
	"encoding/hex"
	"errors"
	"time"

	"github.com/jmoiron/sqlx"
	"github.com/rs/zerolog/log"
	"golang.org/x/crypto/bcrypt"

	"code.chrissexton.org/cws/cabinet/config"
	"code.chrissexton.org/cws/cabinet/db"
)

type User struct {
	*db.Database

	ID         int64
	Name       string
	Hash       []byte
	AuthKey    string `db:"auth_key"`
	Invalidate time.Time
}

func PrepareTable(tx *sqlx.Tx) error {
	q := `create table if not exists users (
		id integer primary key,
		name text unique not null,
		hash text not null,
		auth_key text,
		invalidate datetime
		)`
	_, err := tx.Exec(q)
	return err
}

func makeKey() (string, error) {
	keySize := config.GetInt("key.size", 10)
	buf := make([]byte, keySize)
	_, err := rand.Read(buf)
	if err != nil {
		return "", err
	}
	key := hex.EncodeToString(buf)
	log.Debug().Msgf("Encoded secret key %s as %s", string(buf), key)
	return key, nil
}

func New(db *db.Database, name, password string) (*User, error) {
	q := `insert or replace into users values (null, ?, ?, ?, ?)`

	key, err := makeKey()
	if err != nil {
		return nil, err
	}
	invalidate := time.Now().Add(time.Duration(config.GetInt("invalidate.hours", 7*24)) * time.Hour)
	hash, err := bcrypt.GenerateFromPassword([]byte(password), config.GetInt("hash.cost", 10))
	if err != nil {
		return nil, err
	}

	res, err := db.Exec(q, name, hash, key, invalidate)
	if err != nil {
		return nil, err
	}
	id, err := res.LastInsertId()
	if err != nil {
		return nil, err
	}
	u := &User{
		ID:         id,
		Name:       name,
		AuthKey:    key,
		Invalidate: invalidate,
	}
	u.Set(password)
	return u, nil
}

func Get(db *db.Database, name string) (*User, error) {
	q := `select * from users where name = ?`
	u := &User{}
	if err := db.Get(u, q, name); err != nil {
		return nil, err
	}
	return u, nil
}

func (u *User) Set(newPassword string) error {
	hash, err := bcrypt.GenerateFromPassword([]byte(newPassword), 0)
	if err != nil {
		return err
	}
	u.Hash = hash
	return nil
}

func (u *User) Validate(password string) bool {
	err := bcrypt.CompareHashAndPassword(u.Hash, []byte(password))
	if err != nil {
		log.Debug().Err(err).Msg("incorrect credentials")
		return false
	}
	return true
}

func GetByKey(db *db.Database, key string) (*User, error) {
	q := `select * from users where auth_key = ?`
	u := &User{}
	invalid := errors.New("invalid key")
	if err := db.Get(u, q, key); err != nil {
		if err.Error() == "sql: no rows in result set" {
			return nil, invalid
		}
		return nil, err
	}
	if u.Invalidate.Before(time.Now()) {
		return nil, invalid
	}
	return u, nil
}