package db

import (
	"database/sql"
	"errors"
	"fmt"

	"github.com/bluesky-social/indigo/atproto/syntax"
	"tangled.org/core/knotfeed"
)

func (d *DB) LoadFeedCursor(knot string) (knotfeed.Cursor, error) {
	var seq int64
	var token string
	err := d.QueryRow(
		`select seq, feed from feed_cursors where knot = ?`, knot,
	).Scan(&seq, &token)
	if errors.Is(err, sql.ErrNoRows) {
		return knotfeed.Cursor{}, nil
	}
	if err != nil {
		return knotfeed.Cursor{}, err
	}
	feed, err := knotfeed.ParseFeed(token)
	if err != nil {
		return knotfeed.Cursor{}, fmt.Errorf("feed cursor for %s: %w", knot, err)
	}
	return knotfeed.NewCursor(feed, seq), nil
}

func (d *DB) StoreFeedCursor(knot string, cursor knotfeed.Cursor) error {
	_, err := d.Exec(
		`insert into feed_cursors (knot, seq, feed) values (?, ?, ?)
		 on conflict(knot) do update set seq = excluded.seq, feed = excluded.feed`,
		knot, cursor.Seq(), cursor.Feed().Token(),
	)
	return err
}

func (d *DB) FeedRefSha(repoDid syntax.DID, rkey syntax.RecordKey) (knotfeed.ObjectID, bool, error) {
	var raw string
	err := d.QueryRow(
		`select sha from feed_refs where repo_did = ? and rkey = ?`,
		repoDid.String(), rkey.String(),
	).Scan(&raw)
	if errors.Is(err, sql.ErrNoRows) {
		return knotfeed.ObjectID{}, false, nil
	}
	if err != nil {
		return knotfeed.ObjectID{}, false, err
	}
	sha, ok := knotfeed.ParseObjectID(raw)
	if !ok {
		return knotfeed.ObjectID{}, false, fmt.Errorf("ref state for %s at %s stored sha %q", repoDid, rkey, raw)
	}
	return sha, true, nil
}

func (d *DB) PutFeedRef(repoDid syntax.DID, rkey syntax.RecordKey, sha knotfeed.ObjectID) error {
	_, err := d.Exec(
		`insert into feed_refs (repo_did, rkey, sha) values (?, ?, ?)
		 on conflict(repo_did, rkey) do update set sha = excluded.sha`,
		repoDid.String(), rkey.String(), sha.String(),
	)
	return err
}

func (d *DB) DeleteFeedRef(repoDid syntax.DID, rkey syntax.RecordKey) error {
	_, err := d.Exec(
		`delete from feed_refs where repo_did = ? and rkey = ?`,
		repoDid.String(), rkey.String(),
	)
	return err
}

func (d *DB) DeleteFeedRefsByRepoDid(repoDid syntax.DID) error {
	_, err := d.Exec(`delete from feed_refs where repo_did = ?`, repoDid.String())
	return err
}