package store

import (
	"context"
	"crypto/sha256"
	"database/sql"
	"encoding/hex"
	"time"

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

type User struct {
	ID        int64    `json:"id"`
	FirstName string   `json:"first_name"`
	LastName  string   `json:"last_name"`
	Username  string   `json:"username"`
	Email     string   `json:"email"`
	Password  password `json:"-"`
	IsActive  bool     `json:"is_active"`
	RoleID    int64    `json:"role_id"`
	Role      Role     `json:"role"`
	CreatedAt string   `json:"created_at"`
	UpdatedAt string   `json:"updated_at"`
}

type password struct {
	text *string `validate:"required,password"`
	hash []byte
}

func (p *password) Set(password string) error {
	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		return err
	}
	p.text = &password
	p.hash = hash

	return nil
}

type UserStore struct {
	db *sql.DB
}

func (s *UserStore) Create(ctx context.Context, tx *sql.Tx, user *User) error {
	query := `
		INSERT INTO users (first_name, last_name, username, email, password, role_id)
		VALUES ($1, $2, $3, $4, $5, (SELECT id FROM roles WHERE name = $6)) RETURNING id, created_at, updated_at
	`
	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	role := user.Role.Name
	if role == "" {
		role = "user"
	}

	err := tx.QueryRowContext(
		ctx,
		query,
		user.FirstName,
		user.LastName,
		user.Username,
		user.Email,
		user.Password.hash,
		role,
	).Scan(&user.ID, &user.CreatedAt, &user.UpdatedAt)
	if err != nil {
		switch {
		case err.Error() == `pq: duplicate key value violates unique constraint "users_username_key"`:
			return ErrDuplicateUsername
		case err.Error() == `pq: duplicate key value violates unique constraint "users_email_key"`:
			return ErrDuplicateEmail
		default:
			return err
		}
	}

	return nil
}

func (s *UserStore) GetByID(ctx context.Context, id int64) (*User, error) {
	query := `
		SELECT users.id, first_name, last_name, username, email, password, created_at, updated_at, roles.*
		FROM users
		JOIN roles ON (users.role_id = roles.id)
		WHERE users.id = $1
		AND is_active = true
	`
	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	user := &User{}
	err := s.db.QueryRowContext(ctx, query, id).Scan(
		&user.ID,
		&user.FirstName,
		&user.LastName,
		&user.Username,
		&user.Email,
		&user.Password.hash,
		&user.CreatedAt,
		&user.UpdatedAt,
		&user.Role.ID,
		&user.Role.Name,
		&user.Role.Level,
		&user.Role.Description,
	)
	if err != nil {
		switch err {
		case sql.ErrNoRows:
			return nil, ErrNotFound
		default:
			return nil, err
		}
	}

	return user, nil
}

func (s *UserStore) GetByEmail(ctx context.Context, email string) (*User, error) {
	query := `
		SELECT users.id, first_name, last_name, username, email, password, created_at, updated_at, roles.*
		FROM users
		JOIN roles ON (users.role_id = roles.id)
		WHERE email = $1
		AND is_active = true
		`

	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	user := &User{}

	err := s.db.QueryRowContext(ctx, query, email).Scan(
		&user.ID,
		&user.FirstName,
		&user.LastName,
		&user.Username,
		&user.Email,
		&user.Password.hash,
		&user.CreatedAt,
		&user.UpdatedAt,
		&user.Role.ID,
		&user.Role.Name,
		&user.Role.Level,
		&user.Role.Description,
	)
	if err != nil {
		switch err {
		case sql.ErrNoRows:
			return nil, ErrNotFound
		default:
			return nil, err
		}
	}

	return user, nil
}

func (s *UserStore) Update(ctx context.Context, user *User) error {
	query := `
		UPDATE users
		SET first_name = $1, last_name = $2, username = $3, email = $4, password = $5
		WHERE id = $6
	`
	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	_, err := s.db.ExecContext(
		ctx,
		query,
		user.FirstName,
		user.LastName,
		user.Username,
		user.Email,
		user.Password.hash,
		user.ID,
	)
	if err != nil {
		return err
	}

	return nil
}

func (s *UserStore) CreateAndInvite(ctx context.Context, user *User, token string, invitationExp time.Duration) error {
	return withTx(s.db, ctx, func(tx *sql.Tx) error {
		if err := s.Create(ctx, tx, user); err != nil {
			return err
		}

		if err := s.createUserInvitation(ctx, tx, user.ID, invitationExp, token); err != nil {
			return err
		}

		return nil
	})
}

func (s *UserStore) Activate(ctx context.Context, token string) error {
	return withTx(s.db, ctx, func(tx *sql.Tx) error {
		// Find the user that this token belongs to
		user, err := getUserFromInvitation(ctx, tx, token)
		if err != nil {
			return err
		}

		// Update the user's status to active
		user.IsActive = true
		if err := s.update(ctx, tx, user); err != nil {
			return err
		}

		// Delete the token from the invitations table
		if err := s.deleteUserInvitation(ctx, tx, user.ID); err != nil {
			return err
		}

		return nil
	})
}

func (s *UserStore) Delete(ctx context.Context, id int64) error {
	return withTx(s.db, ctx, func(tx *sql.Tx) error {
		if err := s.delete(ctx, tx, id); err != nil {
			return err
		}

		if err := s.deleteUserInvitation(ctx, tx, id); err != nil {
			return err
		}

		return nil
	})
}

// * Soft delete user
func (s *UserStore) DeleteUser(ctx context.Context, id int64) error {
	query := `UPDATE users SET is_active = false WHERE id = $1`

	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	_, err := s.db.ExecContext(ctx, query, id)
	if err != nil {
		return err
	}

	return nil
}

func (p *password) Compare(password string) error {
	return bcrypt.CompareHashAndPassword(p.hash, []byte(password))
}

func getUserFromInvitation(ctx context.Context, tx *sql.Tx, token string) (*User, error) {
	query := `
		SELECT u.id, u.first_name, u.last_name, u.username, u.email, u.created_at, u.updated_at, is_active
		FROM users u
		JOIN invitations i ON u.id = i.user_id
		WHERE i.token = $1 AND i.expiry > $2
	`

	hashed := sha256.Sum256([]byte(token))
	hashedToken := hex.EncodeToString(hashed[:])

	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	user := &User{}
	err := tx.QueryRowContext(ctx, query, hashedToken, time.Now()).Scan(
		&user.ID,
		&user.FirstName,
		&user.LastName,
		&user.Username,
		&user.Email,
		&user.CreatedAt,
		&user.UpdatedAt,
		&user.IsActive,
	)
	if err != nil {
		switch err {
		case sql.ErrNoRows:
			return nil, ErrNotFound
		default:
			return nil, err
		}
	}

	return user, nil
}

func (s *UserStore) createUserInvitation(ctx context.Context, tx *sql.Tx, userID int64, exp time.Duration, token string) error {
	query := `
		INSERT INTO invitations (user_id, token, expiry)
		VALUES ($1, $2, $3)
	`
	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	_, err := tx.ExecContext(ctx, query, userID, token, time.Now().Add(exp))
	if err != nil {
		return err
	}

	return nil
}

func (s *UserStore) update(ctx context.Context, tx *sql.Tx, user *User) error {
	query := `
		UPDATE users
		SET first_name = $1, last_name = $2, username = $3, email = $4, is_active = $5
		WHERE id = $6
	`
	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	_, err := tx.ExecContext(
		ctx,
		query,
		user.FirstName,
		user.LastName,
		user.Username,
		user.Email,
		user.IsActive,
		user.ID,
	)
	if err != nil {
		return err
	}

	return nil
}

func (s *UserStore) deleteUserInvitation(ctx context.Context, tx *sql.Tx, userID int64) error {
	query := `DELETE FROM invitations WHERE user_id = $1`

	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	_, err := tx.ExecContext(ctx, query, userID)
	if err != nil {
		return err
	}

	return nil
}

func (s *UserStore) delete(ctx context.Context, tx *sql.Tx, id int64) error {
	query := `DELETE FROM users WHERE id = $1`

	ctx, cancel := context.WithTimeout(ctx, QueryTimeout)
	defer cancel()

	_, err := tx.ExecContext(ctx, query, id)
	if err != nil {
		return err
	}

	return nil
}