package domain

import (
	"crypto/hmac"
	"crypto/sha256"
	"errors"
	"testing"
	"time"
)

func testRoster(now time.Time) []JoinAuthorisation {
	roster := make([]JoinAuthorisation, 6)
	for i := range roster {
		roster[i] = JoinAuthorisation{MatchID: "match-1", ServerID: "server-1", Protocol: "v1", PlayerID: string(rune('a' + i)), SteamID: string(rune('A' + i)), Slot: i, Team: i / 3, Generation: 1, ExpiresAt: now.Add(time.Hour)}
	}
	return roster
}

func TestRankedReconnectReclaimsWithinGraceAndFencesOldGeneration(t *testing.T) {
	now := time.Unix(1000, 0)
	r, err := NewRankedConnections("match-1", "server-1", "v1", testRoster(now))
	if err != nil {
		t.Fatal(err)
	}
	auth := testRoster(now)[0]
	if gen, err := r.Admit(auth, now); err != nil || gen != 1 {
		t.Fatalf("initial admit = %d, %v", gen, err)
	}
	if err := r.Disconnect("a", 1, now.Add(time.Second)); err != nil {
		t.Fatal(err)
	}
	if gen, err := r.Admit(auth, now.Add(time.Second+RankedReconnectGrace)); err != nil || gen != 2 {
		t.Fatalf("boundary reclaim = %d, %v", gen, err)
	}
	if err := r.Disconnect("a", 1, now.Add(62*time.Second)); !errors.Is(err, ErrConnectionFenced) {
		t.Fatalf("old connection was not fenced: %v", err)
	}
	if err := r.Disconnect("a", 2, now.Add(62*time.Second)); err != nil {
		t.Fatal(err)
	}
	if gen, err := r.Admit(auth, now.Add(63*time.Second)); err != nil || gen != 3 {
		t.Fatalf("repeated reclaim with existing authorisation = %d, %v", gen, err)
	}
}

func TestRankedReconnectRejectsWrongBindingAndExpiredGrace(t *testing.T) {
	now := time.Unix(1000, 0)
	r, err := NewRankedConnections("match-1", "server-1", "v1", testRoster(now))
	if err != nil {
		t.Fatal(err)
	}
	bad := testRoster(now)[0]
	bad.ServerID = "server-2"
	if _, err := r.Admit(bad, now); !errors.Is(err, ErrJoinAuthorisation) {
		t.Fatalf("wrong server accepted: %v", err)
	}
	wrongIdentity := testRoster(now)[0]
	wrongIdentity.SteamID = "steam-attacker"
	if _, err := r.Admit(wrongIdentity, now); !errors.Is(err, ErrJoinAuthorisation) {
		t.Fatalf("wrong SteamID accepted: %v", err)
	}
	if _, err := r.Admit(testRoster(now)[0], now); err != nil {
		t.Fatal(err)
	}
	if err := r.Disconnect("a", 1, now); err != nil {
		t.Fatal(err)
	}
	if _, err := r.Admit(testRoster(now)[0], now.Add(RankedReconnectGrace+time.Nanosecond)); !errors.Is(err, ErrReconnectExpired) {
		t.Fatalf("expired reclaim error = %v", err)
	}
}

func TestRankedReconnectRejectsDuplicateAndTimeReversedLifecycle(t *testing.T) {
	now := time.Unix(1000, 0)
	r, err := NewRankedConnections("match-1", "server-1", "v1", testRoster(now))
	if err != nil {
		t.Fatal(err)
	}
	auth := testRoster(now)[0]
	if err := r.Disconnect("a", 1, now); !errors.Is(err, ErrConnectionFenced) {
		t.Fatalf("disconnect before admission error = %v", err)
	}
	if _, err := r.Admit(auth, time.Time{}); !errors.Is(err, ErrJoinAuthorisation) {
		t.Fatalf("zero-time admission error = %v", err)
	}
	if _, err := r.Admit(auth, now); err != nil {
		t.Fatal(err)
	}
	if _, err := r.Admit(auth, now.Add(time.Second)); !errors.Is(err, ErrConnectionFenced) {
		t.Fatalf("duplicate active admission error = %v", err)
	}
	if err := r.Disconnect("a", 1, now.Add(2*time.Second)); err != nil {
		t.Fatal(err)
	}
	if err := r.Disconnect("a", 1, now.Add(30*time.Second)); !errors.Is(err, ErrConnectionFenced) {
		t.Fatalf("duplicate disconnect error = %v", err)
	}
	if _, err := r.Admit(auth, now.Add(time.Second)); !errors.Is(err, ErrJoinAuthorisation) {
		t.Fatalf("time-reversed reclaim error = %v", err)
	}
}

func TestRankedRosterRejectsDuplicateSlots(t *testing.T) {
	now := time.Unix(1000, 0)
	roster := testRoster(now)
	roster[1].Slot = roster[0].Slot
	if _, err := NewRankedConnections("match-1", "server-1", "v1", roster); !errors.Is(err, ErrJoinAuthorisation) {
		t.Fatalf("duplicate slot accepted: %v", err)
	}
}

func TestRankedRosterRejectsTeamSlotMismatch(t *testing.T) {
	now := time.Unix(1000, 0)
	roster := testRoster(now)
	roster[3].Team = 0
	if _, err := NewRankedConnections("match-1", "server-1", "v1", roster); !errors.Is(err, ErrJoinAuthorisation) {
		t.Fatalf("team/slot mismatch accepted: %v", err)
	}
}

func TestRankedAbandonCooldownUsesRollingSevenDayLadder(t *testing.T) {
	now := time.Unix(1000, 0)
	r, err := NewRankedConnections("match-1", "server-1", "v1", testRoster(now))
	if err != nil {
		t.Fatal(err)
	}
	if _, err := r.Admit(testRoster(now)[0], now); err != nil {
		t.Fatal(err)
	}
	if err := r.Disconnect("a", 1, now); err != nil {
		t.Fatal(err)
	}
	history := map[string][]time.Time{"a": {now.Add(-6 * 24 * time.Hour), now.Add(-time.Hour), now.Add(-8 * 24 * time.Hour)}}
	got := r.ExpireGrace(now.Add(RankedReconnectGrace+time.Second), history)
	if len(got) != 1 || got[0].PlayerID != "a" || got[0].Cooldown != time.Hour {
		t.Fatalf("unexpected abandonment: %+v", got)
	}
	if again := r.ExpireGrace(now.Add(2*time.Minute), history); len(again) != 0 {
		t.Fatalf("abandonment repeated: %+v", again)
	}
}

func TestSignedJoinAuthorisationBindsEveryClaimBeforeReclaim(t *testing.T) {
	now := time.Unix(1000, 0).UTC()
	r, err := NewRankedConnections("match-1", "server-1", "v1", testRoster(now))
	if err != nil {
		t.Fatal(err)
	}
	key := []byte("test-signing-key")
	sign := func(payload []byte) ([]byte, error) {
		mac := hmac.New(sha256.New, key)
		_, _ = mac.Write(payload)
		return mac.Sum(nil), nil
	}
	verify := func(payload, signature []byte) bool {
		expected, _ := sign(payload)
		return hmac.Equal(expected, signature)
	}
	signed, err := SignJoinAuthorisation(testRoster(now)[0], sign)
	if err != nil {
		t.Fatal(err)
	}
	if gen, err := r.AdmitSigned(signed, verify, now); err != nil || gen != 1 {
		t.Fatalf("signed initial admit = %d, %v", gen, err)
	}
	if err := r.Disconnect("a", 1, now); err != nil {
		t.Fatal(err)
	}
	tampered := signed
	tampered.Authorisation.Slot = 1
	if _, err := r.AdmitSigned(tampered, verify, now.Add(time.Second)); !errors.Is(err, ErrJoinAuthorisation) {
		t.Fatalf("tampered slot accepted: %v", err)
	}
	if _, err := r.AdmitSigned(signed, func([]byte, []byte) bool { return false }, now.Add(RankedReconnectGrace)); !errors.Is(err, ErrJoinAuthorisation) {
		t.Fatalf("unverified signature accepted: %v", err)
	}
	if gen, err := r.AdmitSigned(signed, verify, now.Add(RankedReconnectGrace)); err != nil || gen != 2 {
		t.Fatalf("signed reclaim = %d, %v", gen, err)
	}
}