package channelbridge

import (
	"bytes"
	"context"
	"log/slog"
	"strings"
	"testing"
	"time"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/channel/adapter"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/channel/session"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/loop"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/model"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/user"
)

func itoa(n int) string {
	if n == 0 {
		return "0"
	}
	var b [20]byte
	i := len(b)
	for n > 0 {
		i--
		b[i] = byte('0' + n%10)
		n /= 10
	}
	return string(b[i:])
}

func groupSender(i int) adapter.UnifiedMessage {
	return adapter.UnifiedMessage{
		Platform:    "kook",
		ChannelID:   "-100",
		ChannelType: adapter.ChannelGroup,
		GroupID:     "-100",
		SenderID:    "u" + itoa(i),
		Content:     "spam " + itoa(i),
		ContentType: adapter.ContentText,
	}
}

func groupOwnerMsg(i int) adapter.UnifiedMessage {
	m := groupSender(i)
	m.Sender = adapter.Actor{Role: adapter.RoleOwner}
	return m
}

// TestFlowGate_RateLimitDropsNonOwnerAndAudits 验证闸门已接入
// 入口（onMessage），且被限流的非主人消息会被丢弃并经
// OnRejected 审计钩子暴露原因。丢弃路径是同步的
// （不会派生工作 goroutine），因此断言是确定性的。
func TestFlowGate_RateLimitDropsNonOwnerAndAudits(t *testing.T) {
	t.Parallel()

	chat := &stubChatter{res: &loop.Result{Text: "hi"}}
	sess := &stubSessions{sess: session.Session{SessionID: "sess-g", IsGroup: true, Owner: false, MemWritable: false}}
	var rejected []string
	b, err := New(Options{
		Loop: chat, Sessions: sess, Owner: &user.OwnerProfile{},
		OnRejected: func(_ adapter.UnifiedMessage, reason string) { rejected = append(rejected, reason) },
	})
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	ad := &fakeAdapter{name: "kook", cfg: map[string]any{"bot_token": "x", "msgPerMin": 1}}
	b.Add(ad)

	// 第一条消息被放行（异步工作项），只对第二条入审计，
	// 它被每分钟总量上限拒绝。
	b.onMessage(context.Background(), groupSender(0), ad)
	b.onMessage(context.Background(), groupSender(1), ad)

	if len(rejected) != 1 || rejected[0] != "rate_limited" {
		t.Fatalf("rejected = %v, want [rate_limited]", rejected)
	}
}

// TestFlowGate_OwnerPrivateBypassesGate 验证主人消息完全绕过流控
// 闸门：即使限流很激进，主人消息也绝不会以
// rate_limited / review_pruned / capped 被丢弃。
func TestFlowGate_OwnerPrivateBypassesGate(t *testing.T) {
	t.Parallel()

	chat := &stubChatter{res: &loop.Result{Text: "hi"}}
	sess := &stubSessions{sess: session.Session{SessionID: "sess-1", Owner: true, MemWritable: true}}
	var rejected []string
	b, err := New(Options{
		Loop: chat, Sessions: sess, Owner: testOwnerProfile("kook", "u0", "u1", "u2"),
		OnRejected: func(_ adapter.UnifiedMessage, reason string) { rejected = append(rejected, reason) },
	})
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	ad := &fakeAdapter{name: "kook", cfg: map[string]any{"bot_token": "x", "groupMsgPerMin": 1, "maxMessages": 1}}
	b.Add(ad)

	// 三条主人消息：若闸门生效，第 2、3 条会被限流
	// / 触及上限并到达 OnRejected。主人绕过则审计为空。
	for i := 0; i < 3; i++ {
		b.onMessage(context.Background(), groupOwnerMsg(i), ad)
	}
	if len(rejected) != 0 {
		t.Fatalf("owner messages must bypass the gate, got rejected %v", rejected)
	}
}

// TestFlowGate_GateOptionsDefaults 钉住「配置→限制」的解析规则，
// 它保证旧的 CHANNELS_JSON 账号向后兼容：键缺失 → 关闭，0 → 保护性
// 默认值，负值 → 关闭，正值 → 固定为该值。**私聊（陌生人）限流同一口径，
// 但缺省侧相反**：键缺失/非整数/0 一律取保护性默认 6（裁决③「陌生人必须有流控」
// ＋裁决 13「流控时间要可配置」）——绝不因为「没配」而静默关掉。
func TestFlowGate_GateOptionsDefaults(t *testing.T) {
	t.Parallel()

	b, err := New(Options{Loop: &stubChatter{}, Sessions: &stubSessions{}})
	if err != nil {
		t.Fatalf("New: %v", err)
	}

	// direct 列用**字面量 6**（该常量由 adapter/flowgate_direct_test.go 的
	// TestFlowDirectDefaultIsPinned 钉住）：缺键时若解析成 0（= 关掉流控）本用例必须红。
	cases := []struct {
		name       string
		cfg        map[string]any
		group, max int
		direct     int
	}{
		{"absent keys off", map[string]any{"bot_token": "x"}, 0, 0, 6},
		{"group 0 defaults 6", map[string]any{"bot_token": "x", "groupMsgPerMin": 0}, 6, 0, 6},
		{"group -1 off", map[string]any{"bot_token": "x", "groupMsgPerMin": -1}, 0, 0, 6},
		{"group 10 pinned", map[string]any{"bot_token": "x", "groupMsgPerMin": 10}, 10, 0, 6},
		{"max 0 defaults 50", map[string]any{"bot_token": "x", "maxMessages": 0}, 0, 50, 6},
		{"max -1 off", map[string]any{"bot_token": "x", "maxMessages": -1}, 0, 0, 6},
		{"max 80 pinned", map[string]any{"bot_token": "x", "maxMessages": 80}, 0, 80, 6},
		{"direct 0 defaults 6", map[string]any{"bot_token": "x", "directMsgPerMin": 0}, 0, 0, 6},
		{"direct -1 off", map[string]any{"bot_token": "x", "directMsgPerMin": -1}, 0, 0, 0},
		{"direct 12 pinned", map[string]any{"bot_token": "x", "directMsgPerMin": 12}, 0, 0, 12},
		{"direct non-numeric defaults 6", map[string]any{"bot_token": "x", "directMsgPerMin": "abc"}, 0, 0, 6},
	}
	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			opts := b.gateOptions(&fakeAdapter{name: "kook", cfg: c.cfg})
			if opts.GroupMsgPerMin != c.group {
				t.Fatalf("GroupMsgPerMin = %d, want %d", opts.GroupMsgPerMin, c.group)
			}
			if opts.MaxMessages != c.max {
				t.Fatalf("MaxMessages = %d, want %d", opts.MaxMessages, c.max)
			}
			if opts.DirectMsgPerMin != c.direct {
				t.Fatalf("DirectMsgPerMin = %d, want %d（缺失/0 走保护性默认 6，负值=关闭，正值=该值）",
					opts.DirectMsgPerMin, c.direct)
			}
		})
	}
}

// TestFlowGate_DirectLimitFromAccountConfig 验证 directMsgPerMin 从账号配置到闸门的
// **整条链**：键缺失 ⇒ 保护性默认 6 条/分真的拦下第 7 条；正值 ⇒ 该值；负值 ⇒ 关闭
// （全部放行）。计数按发送者独立（AllowDirect 的会话键含 sender）。
func TestFlowGate_DirectLimitFromAccountConfig(t *testing.T) {
	t.Parallel()

	cases := []struct {
		name string
		cfg  map[string]any
		// allowed 是限制内会被放行的条数；off = 限制被显式关闭（第 allowed+1 条不会被拒）。
		allowed int
		off     bool
	}{
		{"absent key keeps the protective default 6", map[string]any{"bot_token": "x"}, 6, false},
		{"pinned 2", map[string]any{"bot_token": "x", "directMsgPerMin": 2}, 2, false},
		{"negative disables the limit", map[string]any{"bot_token": "x", "directMsgPerMin": -1}, 12, true},
	}
	for _, c := range cases {
		c := c
		t.Run(c.name, func(t *testing.T) {
			t.Parallel()

			b, ad := newGateBridge(t, c.cfg)
			gate := b.gateFor(ad)
			if gate == nil {
				t.Fatal("gateFor = nil, want a gate for the configured adapter")
			}
			for i := 0; i < c.allowed; i++ {
				if !gate.AllowDirect(strangerDirectMsg("777", "第 "+itoa(i)+" 句")) {
					t.Fatalf("额度内第 %d 条被拒，want allowed", i+1)
				}
			}
			// 限制生效时第 allowed+1 条必须被拒（off=false）；关闭时（off=true）必须放行。
			if over := gate.AllowDirect(strangerDirectMsg("777", "第 N+1 句")); over != c.off {
				t.Fatalf("第 %d 条的放行结果 = %v（off=%v），want %v",
					c.allowed+1, over, c.off, c.off)
			}
			// 另一个发送者有独立额度：不被前一个发送者挤占。
			if !gate.AllowDirect(strangerDirectMsg("888", "我是另一个人")) {
				t.Fatal("另一个发送者的额度被挤占")
			}
		})
	}
}

// newGateBridge 构建一条只用于流控解析的桥接器（telegram 适配器 + 给定账号配置），
// 使 directMsgPerMin 走与生产完全相同的「Config() → gateOptions」链。
func newGateBridge(t *testing.T, cfg map[string]any) (*Bridge, *fakeAdapter) {
	t.Helper()
	b, err := New(Options{Loop: &stubChatter{}, Sessions: &stubSessions{}})
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	ad := &fakeAdapter{name: "telegram", cfg: cfg}
	b.Add(ad)
	return b, ad
}

// TestFlowGate_DirectLimitOffIsLogged 钉住「负值关闭必须留痕」：主人显式关掉熟人/
// 陌生人私聊流控时，日志里必须出现一条带 source 的 WARN（不许静默关闭）；而正值或
// 缺省（保护性默认）绝不产生这条告警（否则主人会以为流控被关了）。
func TestFlowGate_DirectLimitOffIsLogged(t *testing.T) {
	t.Parallel()

	var buf bytes.Buffer
	log := slog.New(slog.NewTextHandler(&buf, &slog.HandlerOptions{Level: slog.LevelDebug}))
	at := time.Date(2026, 1, 1, 12, 0, 0, 0, time.UTC)
	b, _, ad := newStrangerBridge(t, &stubChatter{}, &captureHistory{}, at, log)

	ad.cfg = map[string]any{"bot_token": "x", "directMsgPerMin": -1}
	if opts := b.gateOptions(ad); opts.DirectMsgPerMin != 0 {
		t.Fatalf("DirectMsgPerMin = %d, want 0（负值 = 关闭）", opts.DirectMsgPerMin)
	}
	logged := buf.String()
	if !strings.Contains(logged, "non-owner private rate limit turned off") ||
		!strings.Contains(logged, "source=services/channelbridge/flowgate") ||
		!strings.Contains(logged, "directMsgPerMin") {
		t.Fatalf("负值关闭流控没有留下带 source 的可见告警：%q", logged)
	}

	// 正值：不告警，且额度就是该值。
	buf.Reset()
	ad.cfg = map[string]any{"bot_token": "x", "directMsgPerMin": 12}
	if opts := b.gateOptions(ad); opts.DirectMsgPerMin != 12 {
		t.Fatalf("DirectMsgPerMin = %d, want 12", opts.DirectMsgPerMin)
	}
	if got := buf.String(); got != "" {
		t.Fatalf("正值不该产生「流控被关闭」告警：%q", got)
	}

	// 缺省（保护性默认）：同样不告警 —— 默认不是「主人关掉了它」。
	buf.Reset()
	ad.cfg = map[string]any{"bot_token": "x"}
	if opts := b.gateOptions(ad); opts.DirectMsgPerMin != adapter.FlowDirectDefault {
		t.Fatalf("DirectMsgPerMin = %d, want the protective default %d",
			opts.DirectMsgPerMin, adapter.FlowDirectDefault)
	}
	if got := buf.String(); got != "" {
		t.Fatalf("缺省不该产生「流控被关闭」告警：%q", got)
	}
}

// mockLLM 是返回固定补全的 model.Adapter 桩。
type mockLLM struct {
	content string
	err     error
}

func (m *mockLLM) Name() string { return "mock-llm" }
func (m *mockLLM) Chat(_ context.Context, req model.Request, _ model.Options) (model.Response, error) {
	if m.err != nil {
		return model.Response{}, m.err
	}
	return model.Response{Content: m.content, Message: model.TextMessage(model.RoleAssistant, m.content)}, nil
}
func (m *mockLLM) ChatStream(_ context.Context, _ model.Request, _ func(model.StreamEvent)) (model.Response, error) {
	return model.Response{}, nil
}

// TestNewLLMReviewer 验证审查模型被包装成 Reviewer：向
// LLM 询问哪些队列消息该保留，并过滤返回的索引。
func TestNewLLMReviewer(t *testing.T) {
	t.Parallel()

	llm := &mockLLM{content: `[0,1,99,0]`}
	review := NewLLMReviewer(llm, nil)

	msgs := []adapter.UnifiedMessage{
		{SenderID: "a", Content: "x", ContentType: adapter.ContentText},
		{SenderID: "b", Content: "y", ContentType: adapter.ContentText},
		{SenderID: "c", Content: "z", ContentType: adapter.ContentText},
	}
	keep, err := review(context.Background(), msgs)
	if err != nil {
		t.Fatalf("review: %v", err)
	}
	// 越界索引 99 与重复的 0 被丢弃；保留 = [0,1]。
	if len(keep) != 2 || keep[0] != 0 || keep[1] != 1 {
		t.Fatalf("keep = %v, want [0 1]", keep)
	}

	if llm.err != nil {
		t.Fatal("unexpected mock error")
	}
}

// TestNewLLMReviewerError 验证审查模型失败会暴露给闸门，
// 闸门随后回退为 FIFO 淘汰，而不是伪造一个成功。
func TestNewLLMReviewerError(t *testing.T) {
	t.Parallel()

	review := NewLLMReviewer(&mockLLM{err: context.DeadlineExceeded}, nil)
	if _, err := review(context.Background(), []adapter.UnifiedMessage{
		{SenderID: "a", Content: "x", ContentType: adapter.ContentText},
	}); err == nil {
		t.Fatal("expected error from failed review model")
	}
}

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

	got, err := parseKeepIndices(`[2,0,0,5]`, 3)
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	if len(got) != 2 || got[0] != 0 || got[1] != 2 {
		t.Fatalf("keep = %v, want [0 2] (out-of-range/dup dropped)", got)
	}
	if _, err := parseKeepIndices(`not json`, 3); err == nil {
		t.Fatal("expected error for non-JSON")
	}
}