package session

import (
	"context"
	"testing"
	"time"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/channel/adapter"
)

func capsProactive() adapter.Capabilities {
	return adapter.Capabilities{Proactive: true}
}

func capsNoProactive() adapter.Capabilities {
	return adapter.Capabilities{Proactive: false}
}

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

	p := NewProactivePolicy(ProactiveOptions{})
	// A channel that does not declare proactive support is denied regardless of
	// how fresh the last message is.
	if p.Allow(context.Background(), capsNoProactive(), time.Now()) {
		t.Error("Allow() = true with Proactive=false, want false")
	}
}

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

	p := NewProactivePolicy(ProactiveOptions{Window: time.Hour})
	last := time.Now().Add(-30 * time.Minute)
	if !p.Allow(context.Background(), capsProactive(), last) {
		t.Error("Allow() = false within window, want true")
	}
}

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

	p := NewProactivePolicy(ProactiveOptions{Window: time.Hour})
	last := time.Now().Add(-90 * time.Minute)
	if p.Allow(context.Background(), capsProactive(), last) {
		t.Error("Allow() = true beyond window, want false")
	}
}

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

	p := NewProactivePolicy(ProactiveOptions{Window: time.Hour})
	if p.Allow(context.Background(), capsProactive(), time.Time{}) {
		t.Error("Allow() = true with no last message, want false")
	}
}

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

	p := NewProactivePolicy(ProactiveOptions{RateLimit: 3, RateWindow: 10 * time.Second})
	ctx := context.Background()
	for i := 1; i <= 3; i++ {
		if !p.Allow(ctx, capsProactive(), time.Now()) {
			t.Fatalf("Allow() denied on attempt %d, want allowed under limit", i)
		}
	}
	if p.Allow(ctx, capsProactive(), time.Now()) {
		t.Error("Allow() allowed past burst limit, want denied")
	}
}

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

	// telegram/webhook-like channel: proactive capability on, no window, no
	// rate limit → always allowed.
	p := NewProactivePolicy(ProactiveOptions{})
	old := time.Now().Add(-48 * time.Hour)
	for i := 0; i < 5; i++ {
		if !p.Allow(context.Background(), capsProactive(), old) {
			t.Fatalf("Allow() denied on unrestricted channel, want true")
		}
	}
}

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

	ctx := context.Background()

	iLink := ProactivePolicyForPlatform("weixin-ilink")
	now := time.Now()
	if !iLink.Allow(ctx, capsProactive(), now.Add(-23*time.Hour)) {
		t.Error("weixin-ilink allowed only within 24h; 23h old should allow")
	}
	if iLink.Allow(ctx, capsProactive(), now.Add(-25*time.Hour)) {
		t.Error("weixin-ilink 25h old last message should deny")
	}

	oneBot := ProactivePolicyForPlatform("qq-obv11")
	for i := 0; i < oneBotBurstLimit; i++ {
		if !oneBot.Allow(ctx, capsProactive(), now) {
			t.Fatalf("onebot denied on attempt %d, want allowed", i+1)
		}
	}
	if oneBot.Allow(ctx, capsProactive(), now) {
		t.Error("onebot allowed past burst limit, want denied")
	}

	tg := ProactivePolicyForPlatform("telegram")
	if !tg.Allow(ctx, capsProactive(), now.Add(-72*time.Hour)) {
		t.Error("telegram must push freely, want true")
	}
}

// TestProactivePolicyForUnknownPlatformIsConservative 是裁决 06.4.4 的断言：未知平台
// （能力未声明、不在平台清单里）**不得**拿到「无限制」——默认给最严格的限频。
func TestProactivePolicyForUnknownPlatformIsConservative(t *testing.T) {
	t.Parallel()

	ctx := context.Background()
	now := time.Now()
	for _, platform := range []string{"mystery-im", "discord", ""} {
		p := ProactivePolicyForPlatform(platform)
		if p == nil {
			t.Fatalf("ProactivePolicyForPlatform(%q) = nil", platform)
		}
		if p.limiter == nil {
			t.Fatalf("未知平台 %q 拿到了无限制策略，违反裁决 06.4.4", platform)
		}
		for i := 0; i < unknownBurstLimit; i++ {
			if !p.Allow(ctx, capsProactive(), now) {
				t.Fatalf("未知平台 %q 第 %d 条被拒，want allowed（限频内）", platform, i+1)
			}
		}
		if p.Allow(ctx, capsProactive(), now) {
			t.Errorf("未知平台 %q 超出保守限频仍被放行", platform)
		}
	}
}

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

	var p *ProactivePolicy
	if p.Allow(context.Background(), capsProactive(), time.Now()) {
		t.Error("nil policy Allow() = true, want false (fail closed)")
	}

	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	policy := NewProactivePolicy(ProactiveOptions{})
	if policy.Allow(ctx, capsProactive(), time.Now()) {
		t.Error("Allow() with canceled ctx = true, want false")
	}
}

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

	l := NewRateLimiter(2, 50*time.Millisecond)
	if !l.Allow() {
		t.Fatal("first Allow() = false, want true")
	}
	if !l.Allow() {
		t.Fatal("second Allow() = false, want true")
	}
	if l.Allow() {
		t.Fatal("third Allow() = true, want false (limit reached)")
	}

	time.Sleep(60 * time.Millisecond)
	if !l.Allow() {
		t.Fatal("Allow() after window elapsed = false, want true")
	}
}

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

	// A limiter with no limit/window configured is the safe permissive default.
	configs := []*RateLimiter{
		NewRateLimiter(0, 0),
		NewRateLimiter(-1, time.Second),
		NewRateLimiter(0, time.Second),
	}
	for i, l := range configs {
		if !l.Allow() || !l.Allow() {
			t.Errorf("config %d: Allow() = false, want true (unlimited)", i)
		}
	}
	if !(*RateLimiter)(nil).Allow() {
		t.Error("nil rate limiter Allow() = false, want true (permissive)")
	}
}