package main

import (
	"bytes"
	"context"
	"database/sql"
	"flag"
	"fmt"
	"os"

	"pg/src/with"

	_ "github.com/lib/pq"
)

func main() {
	if err := with.Context(run); err != nil {
		panic(err)
	}
}

func run(ctx context.Context) error {
	fs := flag.NewFlagSet(os.Args[0], flag.ContinueOnError)
	c := fs.String("c", "postgresql://pulsegres:pulsegres@localhost:15432", "conn string")
	if err := fs.Parse(os.Args[1:]); err != nil {
		panic(err)
	}

	return with.PSQL(ctx, *c, func(pg *sql.DB) error {
		cleanup := func() error {
			rows, err := pg.QueryContext(ctx, `SELECT oid FROM oids`)
			if err != nil {
				return nil
			}
			defer rows.Close()
			for rows.Next() {
				var oid any
				if err := rows.Scan(&oid); err != nil {
					return err
				}
				pg.ExecContext(ctx, `SELECT lo_unlink($1)`, oid)
			}
			return rows.Err()
		}
		defer cleanup()

		if err := cleanup(); err != nil {
			return fmt.Errorf("failed initial cleanup: %w", err)
		}

		if _, err := pg.ExecContext(ctx, `
			DROP TABLE IF EXISTS oids;
			CREATE TABLE IF NOT EXISTS oids (id INTEGER PRIMARY KEY, oid OID);
		`); err != nil {
			return fmt.Errorf("failed initial table setup: %w", err)
		}

		if _, err := pg.ExecContext(ctx, `
			INSERT INTO oids (
				id,
				oid
			)
			VALUES (
				1,
				lo_from_bytea(
					0,
					$1
				)
			) ON CONFLICT DO NOTHING
		`, []byte("hello world")); err != nil {
			return fmt.Errorf("failed lo_from_bytea: %w", err)
		}

		var got []byte
		row := pg.QueryRowContext(ctx, `SELECT lo_get((SELECT oid FROM oids WHERE id=1))`)
		if err := row.Err(); err != nil {
			return err
		} else if err := row.Scan(&got); err != nil {
			return err
		} else if !bytes.Equal(got, []byte("hello world")) {
			return fmt.Errorf("weird lo_get: %q", got)
		}

		return cleanup()
	})
}