package link

import (
	"context"
	"errors"
	"github.com/jackc/pgtype"
	"github.com/jackc/pgx/v4"
	"github.com/jackc/pgx/v4/pgxpool"
	"net/url"
)

type Repository interface {
	Save(link *Link) error
	FindById(id string) (*Link, error)
	DeleteById(id string) error
}

type PgRepository struct {
	pool *pgxpool.Pool
}

func (r *PgRepository) Save(link *Link) error {
	ctx := context.Background()
	tx, err := r.pool.Begin(ctx)
	if err != nil {
		return err
	}

	sql := `
		INSERT INTO links (id, name, redirect_url, creation_time) 
		VALUES ($1, $2, $3, $4::timestamp)
	`

	_, err = tx.Exec(ctx, sql, link.Id, link.Name, link.RedirectURL.String(), link.CreationTime.Format("2006-01-02 15:04:05"))
	if err != nil {
		_ = tx.Rollback(ctx)
		return err
	}

	if err = tx.Commit(ctx); err != nil {
		return err
	}

	return nil
}

func (r *PgRepository) FindById(id string) (*Link, error) {
	ctx := context.Background()
	tx, err := r.pool.Begin(ctx)
	if err != nil {
		return nil, err
	}

	sql := `
		SELECT id, name, redirect_url, creation_time
		FROM links
		WHERE id = $1
	`

	entity, err := mapRowToEntity(tx.QueryRow(ctx, sql, id))
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, nil
		} else {
			_ = tx.Rollback(ctx)
			return nil, err
		}
	}

	if err = tx.Commit(ctx); err != nil {
		return nil, err
	}

	return entity, nil
}

func (r *PgRepository) DeleteById(id string) error {
	ctx := context.Background()
	tx, err := r.pool.Begin(ctx)
	if err != nil {
		return err
	}

	sql := `
		DELETE FROM links WHERE id = $1
	`

	_, err = tx.Exec(ctx, sql, id)
	if err != nil {
		_ = tx.Rollback(ctx)
		return err
	}

	if err = tx.Commit(ctx); err != nil {
		return err
	}

	return nil
}

func mapRowToEntity(r pgx.Row) (*Link, error) {
	var entity Link
	var urlStr string
	var t pgtype.Timestamp

	if err := r.Scan(&entity.Id, &entity.Name, &urlStr, &t); err != nil {
		return nil, err
	}

	u, err := url.Parse(urlStr)
	if err != nil {
		return nil, err
	}

	entity.RedirectURL = *u
	entity.CreationTime = t.Time

	return &entity, nil
}