package database

import (
	"context"

	"github.com/jackc/pgx/v4"

	"github.com/jackc/pgx/v4/pgxpool"
	"github.com/pkg/errors"
	"gitlab.com/wpetit/goweb/middleware/container"
)

type MigrationFunc func(ctx context.Context, tx pgx.Tx) error

type Migration struct {
	version string
	up      MigrationFunc
	down    MigrationFunc
}

func (m *Migration) Version() string {
	return m.version
}

func (m *Migration) Up(ctx context.Context) error {
	pool, err := m.getDatabaseService(ctx)
	if err != nil {
		return err
	}

	err = WithTx(ctx, pool, func(ctx context.Context, tx pgx.Tx) error {
		return m.up(ctx, tx)
	})

	if err != nil {
		return errors.Wrap(err, "could not apply up migration")
	}

	return nil
}

func (m *Migration) Down(ctx context.Context) error {
	pool, err := m.getDatabaseService(ctx)
	if err != nil {
		return err
	}

	err = WithTx(ctx, pool, func(ctx context.Context, tx pgx.Tx) error {
		return m.down(ctx, tx)
	})

	if err != nil {
		return errors.Wrap(err, "could not apply down migration")
	}

	return nil
}

func (m *Migration) getDatabaseService(ctx context.Context) (*pgxpool.Pool, error) {
	ctn, err := container.From(ctx)
	if err != nil {
		return nil, errors.Wrap(err, "could not retrieve service container")
	}

	pool, err := From(ctn)
	if err != nil {
		return nil, errors.Wrap(err, "could not retrieve database service")
	}

	return pool, nil
}

func NewMigration(version string, up, down MigrationFunc) *Migration {
	return &Migration{
		version: version,
		up:      up,
		down:    down,
	}
}