package migrations

import (
	"context"
	"fmt"
	"os"

	"github.com/jmoiron/sqlx"
	"github.com/stashapp/stash/pkg/logger"
	"github.com/stashapp/stash/pkg/sqlite"
)

func pre32(ctx context.Context, db *sqlx.DB) error {
	// verify that folder-based galleries (those with zip = 0 and path is not null) are
	// not zip-based. If they are zip based then set zip to 1
	// we could still miss some if the path does not exist, but this is the best we can do

	logger.Info("Running pre-migration for schema version 32")

	mm := schema32PreMigrator{
		migrator: migrator{
			db: db,
		},
	}

	return mm.migrate(ctx)
}

type schema32PreMigrator struct {
	migrator
}

func (m *schema32PreMigrator) migrate(ctx context.Context) error {
	const (
		limit    = 1000
		logEvery = 10000
	)

	// query for galleries with zip = 0 and path not null
	result := struct {
		Count int `db:"count"`
	}{0}

	if err := m.db.Get(&result, "SELECT COUNT(*) AS count FROM `galleries` WHERE `zip` = '0' AND `path` IS NOT NULL"); err != nil {
		return err
	}

	if result.Count == 0 {
		return nil
	}

	logger.Infof("Checking %d galleries for incorrect zip value...", result.Count)

	lastID := 0
	count := 0

	for {
		gotSome := false

		if err := m.withTxn(ctx, func(tx *sqlx.Tx) error {
			query := "SELECT `id`, `path` FROM `galleries` WHERE `zip` = '0' AND `path` IS NOT NULL "
			if lastID != 0 {
				query += fmt.Sprintf("AND `id` > %d ", lastID)
			}

			query += fmt.Sprintf("ORDER BY `id` LIMIT %d", limit)

			rows, err := tx.Query(query)
			if err != nil {
				return err
			}
			defer rows.Close()

			for rows.Next() {
				var id int
				var p string

				err := rows.Scan(&id, &p)
				if err != nil {
					return err
				}

				gotSome = true
				lastID = id
				count++

				// if path does not exist, make no changes
				// if it does exist and is a folder, then we ignore it
				// otherwise set zip to 1
				info, err := os.Stat(p)
				if err != nil {
					logger.Warnf("unable to verify if %q is a folder due to error %v. Assuming folder-based.", p, err)
					continue
				}

				if info.IsDir() {
					// ignore it
					continue
				}

				logger.Infof("Correcting %q gallery to be zip-based.", p)

				_, err = tx.Exec("UPDATE `galleries` SET `zip` = '1' WHERE `id` = ?", id)
				if err != nil {
					return err
				}
			}

			return rows.Err()
		}); err != nil {
			return err
		}

		if !gotSome {
			break
		}

		if count%logEvery == 0 {
			logger.Infof("Checked %d galleries", count)
		}
	}

	return nil
}

func init() {
	sqlite.RegisterPreMigration(32, pre32)
}