package sync_test

import (
	"context"
	"io"
	"log/slog"
	"testing"
	"time"

	"github.com/jackc/pgx/v5"
	"github.com/stretchr/testify/require"

	"git.fabledsword.com/bvandeusen/minstrel/internal/sync"
)

// The compactor keeps each entity's latest change however old, so an app
// syncing from 0 still gets an artist nobody has touched in months. It drops
// what a newer row supersedes, and deletes past their retention, raising the
// trimmed mark past the newest delete it dropped.
func TestCompact_KeepsEachEntitysLatestChange_Integration(t *testing.T) {
	pool := testPool(t)
	ctx := context.Background()
	old := time.Now().Add(-90 * 24 * time.Hour)
	recent := time.Now().Add(-time.Hour)

	add := func(entity, op string, at time.Time) int64 {
		t.Helper()
		var id int64
		require.NoError(t, pool.QueryRow(ctx, `INSERT INTO library_changes (entity_type, entity_id, op, changed_at)
			VALUES ('artist', $1, $2, $3) RETURNING id`, entity, op, at).Scan(&id))
		return id
	}
	untouched := add("untouched", "upsert", old)             // kept: latest, however old
	add("edited", "upsert", old)                             // dropped: superseded
	edited := add("edited", "upsert", recent)                // kept
	add("removed-long-ago", "upsert", old)                   // dropped: superseded
	removedLongAgo := add("removed-long-ago", "delete", old) // dropped: past retention
	add("removed-lately", "upsert", old)                     // dropped: superseded
	removedLately := add("removed-lately", "delete", recent) // kept: within retention

	require.NoError(t, sync.Compact(ctx, pool, time.Now().Add(-sync.CompactorRetention),
		slog.New(slog.NewTextHandler(io.Discard, nil))))

	rows, err := pool.Query(ctx, `SELECT id FROM library_changes ORDER BY id`)
	require.NoError(t, err)
	left, err := pgx.CollectRows(rows, pgx.RowTo[int64])
	require.NoError(t, err)
	require.Equal(t, []int64{untouched, edited, removedLately}, left)

	var through int64
	require.NoError(t, pool.QueryRow(ctx, `SELECT through FROM library_changes_trimmed`).Scan(&through))
	require.Equal(t, removedLongAgo, through, "the trimmed mark stands at the newest dropped delete")

	// A second pass finds nothing more, and leaves the mark where it is.
	require.NoError(t, sync.Compact(ctx, pool, time.Now().Add(-sync.CompactorRetention),
		slog.New(slog.NewTextHandler(io.Discard, nil))))
	require.NoError(t, pool.QueryRow(ctx, `SELECT through FROM library_changes_trimmed`).Scan(&through))
	require.Equal(t, removedLongAgo, through)
}