package db

import (
	"context"
	"database/sql"
)

// InsertEvent records an audit-trail row. When e.IPID is set, registry_id
// and cycle_id are resolved from that ip_queue row's current values, so the
// event stays traceable to its address (via registry_id) and prunable at
// the right cycle boundary even after the ip_queue row itself is deleted.
func (d *DB) InsertEvent(ctx context.Context, e Event) error {
	_, err := d.ExecContext(ctx, `
		INSERT INTO events (source_type, source_id, ip_id, registry_id, cycle_id, event_type, payload, occurred_at, created_at)
		VALUES (?, ?, ?, (SELECT registry_id FROM ip_queue WHERE id=?), COALESCE((SELECT cycle_id FROM ip_queue WHERE id=?), 0), ?, ?, ?, ?)
	`, e.SourceType, e.SourceID, e.IPID, e.IPID, e.IPID, e.EventType, e.Payload, timeToDB(e.OccurredAt), timeToDB(Now()))
	return err
}

// ListEventsForIP returns the audit trail for a single IP, most recent
// first — used by the admin detail endpoint.
func (d *DB) ListEventsForIP(ctx context.Context, ipID int64) ([]Event, error) {
	rows, err := d.QueryContext(ctx, `
		SELECT id, source_type, source_id, ip_id, registry_id, cycle_id, event_type, payload, occurred_at, created_at
		FROM events WHERE ip_id=? ORDER BY occurred_at DESC
	`, ipID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	return scanEvents(rows)
}

func (d *DB) ListRecentEvents(ctx context.Context, limit int) ([]Event, error) {
	rows, err := d.QueryContext(ctx, `
		SELECT id, source_type, source_id, ip_id, registry_id, cycle_id, event_type, payload, occurred_at, created_at
		FROM events ORDER BY id DESC LIMIT ?
	`, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	return scanEvents(rows)
}

func scanEvents(rows interface {
	Next() bool
	Scan(...interface{}) error
	Err() error
}) ([]Event, error) {
	var out []Event
	for rows.Next() {
		var e Event
		var ipID *int64
		var registryID sql.NullInt64
		var occurredAt, createdAt string
		if err := rows.Scan(&e.ID, &e.SourceType, &e.SourceID, &ipID, &registryID, &e.CycleID,
			&e.EventType, &e.Payload, &occurredAt, &createdAt); err != nil {
			return nil, err
		}
		e.IPID = ipID
		if registryID.Valid {
			e.RegistryID = registryID.Int64
		}
		var err error
		if e.OccurredAt, err = dbToTime(occurredAt); err != nil {
			return nil, err
		}
		if e.CreatedAt, err = dbToTime(createdAt); err != nil {
			return nil, err
		}
		out = append(out, e)
	}
	return out, rows.Err()
}