package shared_test

import (
	"encoding/base64"
	"strconv"
	"testing"

	"galaxy/lobby/internal/service/shared"

	"github.com/stretchr/testify/require"
)

func TestParsePageDefaults(t *testing.T) {
	t.Parallel()

	page, err := shared.ParsePage("", "")
	require.NoError(t, err)
	require.Equal(t, shared.Page{Size: shared.DefaultPageSize, Offset: 0}, page)
}

func TestParsePageHonoursSize(t *testing.T) {
	t.Parallel()

	page, err := shared.ParsePage("75", "")
	require.NoError(t, err)
	require.Equal(t, shared.Page{Size: 75, Offset: 0}, page)
}

func TestParsePageHonoursToken(t *testing.T) {
	t.Parallel()

	token := shared.EncodeToken(150)
	page, err := shared.ParsePage("", token)
	require.NoError(t, err)
	require.Equal(t, shared.Page{Size: shared.DefaultPageSize, Offset: 150}, page)
}

func TestParsePageRejectsBadSize(t *testing.T) {
	t.Parallel()

	cases := []string{"abc", "0", "-3", strconv.Itoa(shared.MaxPageSize + 1)}
	for _, raw := range cases {
		t.Run(raw, func(t *testing.T) {
			t.Parallel()
			_, err := shared.ParsePage(raw, "")
			require.Error(t, err)
			require.Contains(t, err.Error(), "invalid page_size")
		})
	}
}

func TestParsePageRejectsBadToken(t *testing.T) {
	t.Parallel()

	negative := base64.RawURLEncoding.EncodeToString([]byte("-1"))
	notInt := base64.RawURLEncoding.EncodeToString([]byte("abc"))

	cases := []string{"!!!", negative, notInt}
	for _, raw := range cases {
		t.Run(raw, func(t *testing.T) {
			t.Parallel()
			_, err := shared.ParsePage("", raw)
			require.Error(t, err)
			require.Contains(t, err.Error(), "invalid page_token")
		})
	}
}

func TestEncodeTokenRoundtrip(t *testing.T) {
	t.Parallel()

	token := shared.EncodeToken(42)
	page, err := shared.ParsePage("", token)
	require.NoError(t, err)
	require.Equal(t, 42, page.Offset)
}

func TestWindowFirstPageWithMore(t *testing.T) {
	t.Parallel()

	start, end, nextOffset, hasMore := shared.Window(120, shared.Page{Size: 50})
	require.Equal(t, 0, start)
	require.Equal(t, 50, end)
	require.Equal(t, 50, nextOffset)
	require.True(t, hasMore)
}

func TestWindowMiddlePage(t *testing.T) {
	t.Parallel()

	start, end, nextOffset, hasMore := shared.Window(120, shared.Page{Size: 50, Offset: 50})
	require.Equal(t, 50, start)
	require.Equal(t, 100, end)
	require.Equal(t, 100, nextOffset)
	require.True(t, hasMore)
}

func TestWindowLastPageExact(t *testing.T) {
	t.Parallel()

	start, end, nextOffset, hasMore := shared.Window(100, shared.Page{Size: 50, Offset: 50})
	require.Equal(t, 50, start)
	require.Equal(t, 100, end)
	require.Equal(t, 0, nextOffset)
	require.False(t, hasMore)
}

func TestWindowOffsetPastEnd(t *testing.T) {
	t.Parallel()

	start, end, nextOffset, hasMore := shared.Window(10, shared.Page{Size: 50, Offset: 200})
	require.Equal(t, 10, start)
	require.Equal(t, 10, end)
	require.Equal(t, 0, nextOffset)
	require.False(t, hasMore)
}

func TestWindowZeroSizeFallsBackToDefault(t *testing.T) {
	t.Parallel()

	start, end, _, hasMore := shared.Window(120, shared.Page{Size: 0})
	require.Equal(t, 0, start)
	require.Equal(t, shared.DefaultPageSize, end)
	require.True(t, hasMore)
}