package syncapi_test

import (
	"testing"

	"github.com/dariuszjaniak/warp/server/internal/syncapi"
)

func TestTokenRoundTrips(t *testing.T) {
	for _, tc := range []struct {
		name  string
		token syncapi.Token
		want  string
	}{
		{"the initial token", syncapi.Token{}, "s0"},
		{"events only", syncapi.Token{PDU: 12}, "s12"},
		{"events and receipts", syncapi.Token{PDU: 12, Receipt: 3}, "s12_3"},
		{
			"every stream",
			syncapi.Token{PDU: 1, Receipt: 2, ToDevice: 3, AccountData: 4, Presence: 5, DeviceList: 6},
			"s1_2_3_4_5_6",
		},
		{
			// /messages pages back into history backfilled from other
			// servers, which is numbered downwards from -1.
			"a position inside backfilled history",
			syncapi.Token{PDU: -7},
			"s-7",
		},
		{
			// A zero in the middle has to be written, because the
			// positions are read by place.
			"a gap in the middle",
			syncapi.Token{PDU: 1, Presence: 5},
			"s1_0_0_0_5",
		},
	} {
		t.Run(tc.name, func(t *testing.T) {
			if got := tc.token.String(); got != tc.want {
				t.Fatalf("String() = %q, want %q", got, tc.want)
			}
			parsed, err := syncapi.ParseToken(tc.want)
			if err != nil {
				t.Fatalf("ParseToken(%q): %v", tc.want, err)
			}
			if parsed != tc.token {
				t.Errorf("ParseToken(%q) = %+v, want %+v", tc.want, parsed, tc.token)
			}
		})
	}
}

func TestParseTokenAcceptsAnEmptyString(t *testing.T) {
	// /sync without ?since= and /messages without ?from= both mean "from
	// the beginning"; refusing the empty string would make every caller
	// special-case it.
	parsed, err := syncapi.ParseToken("")
	if err != nil {
		t.Fatalf("ParseToken(\"\"): %v", err)
	}
	if !parsed.IsInitial() {
		t.Errorf("ParseToken(\"\") = %+v, want the initial token", parsed)
	}
}

func TestParseTokenAcceptsAShortToken(t *testing.T) {
	// A token a client stored before a stream existed must go on working:
	// the stream it does not mention reads as "seen nothing", so the
	// client is sent that stream in full once and is in step afterwards.
	parsed, err := syncapi.ParseToken("s7")
	if err != nil {
		t.Fatalf("ParseToken(\"s7\"): %v", err)
	}
	if parsed.PDU != 7 {
		t.Errorf("PDU = %d, want 7", parsed.PDU)
	}
	if parsed.Receipt != 0 || parsed.ToDevice != 0 || parsed.AccountData != 0 || parsed.Presence != 0 {
		t.Errorf("the streams a short token omits must read as zero: %+v", parsed)
	}
}

func TestParseTokenRejectsNonsense(t *testing.T) {
	for _, raw := range []string{
		"nonsense",       // no prefix
		"t1_2",           // a prefix this build does not write
		"s",              // a prefix and nothing else
		"s1_-1",          // a negative position outside the event stream
		"sx",             // not a number
		"s1_",            // a trailing separator
		"s1_2_3_4_5_6_7", // more positions than there are streams
		"s1.5",
	} {
		if _, err := syncapi.ParseToken(raw); err == nil {
			t.Errorf("ParseToken(%q) was accepted", raw)
		}
	}
}

func TestParseTokenIsNotFooledByOverflow(t *testing.T) {
	// A position larger than an int64 is not a position this server ever
	// handed out, and silently wrapping it would mean a client being sent
	// the whole of every room again.
	if _, err := syncapi.ParseToken("s99999999999999999999"); err == nil {
		t.Error("a position that does not fit in an int64 was accepted")
	}
}