package rest

import (
	"context"
	"errors"
	"strings"
	"testing"

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

type fakeStatsRow struct {
	scan func(dest ...any) error
}

func (r fakeStatsRow) Scan(dest ...any) error {
	return r.scan(dest...)
}

func TestLoadExplorerStatsReturnsValues(t *testing.T) {
	var call int
	queryRow := func(_ context.Context, _ string, _ ...any) pgx.Row {
		call++
		return fakeStatsRow{
			scan: func(dest ...any) error {
				target, ok := dest[0].(*int64)
				require.True(t, ok)

				switch call {
				case 1:
					*target = 11
				case 2:
					*target = 22
				case 3:
					*target = 33
				case 4:
					*target = 44
				default:
					t.Fatalf("unexpected query call %d", call)
				}
				return nil
			},
		}
	}

	stats, err := loadExplorerStats(context.Background(), 138, queryRow)
	require.NoError(t, err)
	require.Equal(t, int64(11), stats.TotalBlocks)
	require.Equal(t, int64(22), stats.TotalTransactions)
	require.Equal(t, int64(33), stats.TotalAddresses)
	require.Equal(t, int64(44), stats.LatestBlock)
}

func TestLoadExplorerStatsReturnsErrorWhenQueryFails(t *testing.T) {
	queryRow := func(_ context.Context, query string, _ ...any) pgx.Row {
		return fakeStatsRow{
			scan: func(dest ...any) error {
				if strings.Contains(query, "COUNT(*) FROM transactions") {
					return errors.New("boom")
				}
				target, ok := dest[0].(*int64)
				require.True(t, ok)
				*target = 1
				return nil
			},
		}
	}

	_, err := loadExplorerStats(context.Background(), 138, queryRow)
	require.Error(t, err)
	require.Contains(t, err.Error(), "query total transactions")
}