package channelbridge

import (
	"context"
	"testing"

	"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 verifies the gate is wired into the
// ingress (onMessage) and that a rate-limited non-owner message is dropped with the
// reason surfaced through the OnRejected audit hook. The dropped path is synchronous
// (no worker goroutine is spawned), so the assertion is deterministic.
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)

	// First message is admitted (async worker), only auditing the second, which the
	// total per-minute cap refuses.
	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 verifies owner messages bypass the flow gate
// entirely: even with an aggressive rate limit, an owner message is never dropped as
// rate_limited / review_pruned / capped.
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: &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", "groupMsgPerMin": 1, "maxMessages": 1}}
	b.Add(ad)

	// Three owner messages: if the gate applied, the 2nd and 3rd would be rate
	// limited / capped and reach OnRejected. Owner bypass leaves the audit empty.
	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 pins the config-to-limit resolution that keeps
// old CHANNELS_JSON accounts backward compatible: absent key → off, 0 → protective
// default, negative → off, positive → pinned.
func TestFlowGate_GateOptionsDefaults(t *testing.T) {
	t.Parallel()

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

	cases := []struct {
		name       string
		cfg        map[string]any
		group, max int
	}{
		{"absent keys off", map[string]any{"bot_token": "x"}, 0, 0},
		{"group 0 defaults 6", map[string]any{"bot_token": "x", "groupMsgPerMin": 0}, 6, 0},
		{"group -1 off", map[string]any{"bot_token": "x", "groupMsgPerMin": -1}, 0, 0},
		{"group 10 pinned", map[string]any{"bot_token": "x", "groupMsgPerMin": 10}, 10, 0},
		{"max 0 defaults 50", map[string]any{"bot_token": "x", "maxMessages": 0}, 0, 50},
		{"max -1 off", map[string]any{"bot_token": "x", "maxMessages": -1}, 0, 0},
		{"max 80 pinned", map[string]any{"bot_token": "x", "maxMessages": 80}, 0, 80},
	}
	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)
			}
		})
	}
}

// mockLLM is a model.Adapter stub returning a fixed completion.
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 verifies the review model is wrapped into a Reviewer that asks
// the LLM which queued messages to keep and filters the returned indices.
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)
	}
	// Out-of-range index 99 and the duplicate 0 are dropped; keep = [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 verifies a review-model failure is surfaced to the gate,
// which then falls back to FIFO eviction rather than fabricating a success.
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")
	}
}