package backthink

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"strings"
	"sync"
	"testing"
	"time"

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

// mockExporter 记录已导出的消息，并可按需阻塞或失败，
// 使推送器钩子的非阻塞 / 容错行为可测。
type mockExporter struct {
	mu        sync.Mutex
	msgs      []adapter.UnifiedMessage
	delivered bool
	err       error
	started   chan struct{}
	startOnce sync.Once
	release   chan struct{}
}

func (m *mockExporter) Export(ctx context.Context, msg adapter.UnifiedMessage) (bool, error) {
	m.startOnce.Do(func() {
		if m.started != nil {
			close(m.started)
		}
	})
	if m.release != nil {
		<-m.release
	}
	m.mu.Lock()
	m.msgs = append(m.msgs, msg)
	m.mu.Unlock()
	return m.delivered, m.err
}

func (m *mockExporter) messages() []adapter.UnifiedMessage {
	m.mu.Lock()
	defer m.mu.Unlock()
	return append([]adapter.UnifiedMessage(nil), m.msgs...)
}

// TestPushOutletHTTPPrimaryDelivers 证明自托管服务是
// 主级：负载带着 bearer token 被 POST，2xx 响应
// 被上报为已投递。
func TestPushOutletHTTPPrimaryDelivers(t *testing.T) {
	t.Parallel()
	type payload struct {
		Source    string `json:"source"`
		Title     string `json:"title"`
		Content   string `json:"content"`
		Platform  string `json:"platform"`
		Timestamp int64  `json:"timestamp"`
	}
	var (
		got  payload
		auth string
		ct   string
	)
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		auth = r.Header.Get("Authorization")
		ct = r.Header.Get("Content-Type")
		if err := json.NewDecoder(r.Body).Decode(&got); err != nil {
			t.Errorf("decode payload: %v", err)
		}
		w.WriteHeader(http.StatusNoContent)
	}))
	defer srv.Close()

	exp := NewPushOutlet(PushOutletConfig{
		Enabled: true,
		URL:     srv.URL,
		Token:   "s3cret-token",
		Timeout: 2 * time.Second,
		Log:     discardLog(),
	})
	if exp == nil {
		t.Fatal("NewPushOutlet returned nil for an enabled outlet")
	}
	delivered, err := exp.Export(context.Background(), adapter.UnifiedMessage{
		Platform:  "cyrene-backthink",
		Content:   "晚安，早点睡。",
		Sender:    adapter.Actor{DisplayName: "Cyrene"},
		Timestamp: time.UnixMilli(1700000000000),
	})
	if err != nil || !delivered {
		t.Fatalf("Export = (%v, %v), want (true, nil)", delivered, err)
	}
	if got.Source != "cyrene/backthink" || got.Title != "Cyrene" || got.Content != "晚安，早点睡。" || got.Platform != "cyrene-backthink" {
		t.Fatalf("payload = %+v, want source/title/content/platform set", got)
	}
	if got.Timestamp != 1700000000000 {
		t.Fatalf("timestamp = %d, want 1700000000000", got.Timestamp)
	}
	if auth != "Bearer s3cret-token" {
		t.Fatalf("Authorization = %q, want the bearer token", auth)
	}
	if ct != "application/json" {
		t.Fatalf("Content-Type = %q, want application/json", ct)
	}
}

// TestPushOutletUnreachableLogsGetuiFallback 断言主级不可达是一次
// 记账的未命中（不是错误），会点出待接入的个推降级，且绝不记录
// token。
func TestPushOutletUnreachableLogsGetuiFallback(t *testing.T) {
	t.Parallel()
	srv := httptest.NewServer(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {}))
	url := srv.URL
	srv.Close() // 此时已不可达

	var buf bytes.Buffer
	log := slog.New(slog.NewTextHandler(&buf, nil))
	exp := NewPushOutlet(PushOutletConfig{Enabled: true, URL: url, Token: "s3cret-token", Timeout: 300 * time.Millisecond, Log: log})

	delivered, err := exp.Export(context.Background(), adapter.UnifiedMessage{Content: "hi"})
	if err != nil {
		t.Fatalf("Export err = %v, want nil (logged miss)", err)
	}
	if delivered {
		t.Fatal("Export delivered = true, want false for an unreachable primary")
	}
	if !strings.Contains(buf.String(), "getui") {
		t.Fatalf("log = %q, want the pending Getui fallback note", buf.String())
	}
	if strings.Contains(buf.String(), "s3cret-token") {
		t.Fatalf("log leaked the token: %q", buf.String())
	}
}

// TestPushOutletHTTPErrorReportsMiss 断言主级非 2xx 响应算未命中。
func TestPushOutletHTTPErrorReportsMiss(t *testing.T) {
	t.Parallel()
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		http.Error(w, "nope", http.StatusInternalServerError)
	}))
	defer srv.Close()

	exp := NewPushOutlet(PushOutletConfig{Enabled: true, URL: srv.URL, Timeout: 2 * time.Second, Log: discardLog()})
	delivered, err := exp.Export(context.Background(), adapter.UnifiedMessage{Content: "hi"})
	if err != nil {
		t.Fatalf("Export err = %v, want nil (logged miss)", err)
	}
	if delivered {
		t.Fatal("Export delivered = true, want false for a 500 response")
	}
}

// TestNewPushOutletDisabledOrUnconfigured 覆盖两种降级形态：钩子
// 关闭（nil）与启用但无主级 URL（未命中 + 个推备注）。
func TestNewPushOutletDisabledOrUnconfigured(t *testing.T) {
	t.Parallel()
	if exp := NewPushOutlet(PushOutletConfig{Enabled: false, URL: "http://example.invalid"}); exp != nil {
		t.Fatalf("NewPushOutlet disabled = %v, want nil", exp)
	}

	var buf bytes.Buffer
	log := slog.New(slog.NewTextHandler(&buf, nil))
	exp := NewPushOutlet(PushOutletConfig{Enabled: true, Log: log})
	if exp == nil {
		t.Fatal("NewPushOutlet enabled without a URL = nil, want a fallback-only outlet")
	}
	delivered, err := exp.Export(context.Background(), adapter.UnifiedMessage{Content: "hi"})
	if err != nil || delivered {
		t.Fatalf("Export = (%v, %v), want (false, nil)", delivered, err)
	}
	if !strings.Contains(buf.String(), "getui") {
		t.Fatalf("log = %q, want the Getui fallback note", buf.String())
	}
}

// TestPusherExportsProactiveToOutlet 断言钩子在 IM 投递之后
// 把已投递的主动消息镜像到出口。
func TestPusherExportsProactiveToOutlet(t *testing.T) {
	t.Parallel()
	exp := &mockExporter{delivered: true}
	im := &mockIMAdapter{}
	p := newPusher(nil, im, &mockGate{allow: true}, discardLog()).withExporter(exp)
	p.exportDone = make(chan struct{}, 1)

	res := p.Push(context.Background(), PushRequest{Message: adapter.UnifiedMessage{Content: "在吗"}})
	if !res.Pushed || res.Route != RouteIMBridge {
		t.Fatalf("push = %+v, want pushed via IM bridge", res)
	}
	if im.count() != 1 {
		t.Fatalf("im calls = %d, want 1", im.count())
	}
	select {
	case <-p.exportDone:
	case <-time.After(2 * time.Second):
		t.Fatal("export hook did not run")
	}
	msgs := exp.messages()
	if len(msgs) != 1 || msgs[0].Content != "在吗" {
		t.Fatalf("exported = %+v, want the proactive content", msgs)
	}
}

// TestPusherExportHookNonBlockingAndFailureTolerant 断言挂死/失败的出口
// 绝不延迟推送，也绝不把已投递的主动消息变成
// 失败。
func TestPusherExportHookNonBlockingAndFailureTolerant(t *testing.T) {
	t.Parallel()
	started := make(chan struct{})
	release := make(chan struct{})
	exp := &mockExporter{delivered: false, err: errors.New("outlet down"), started: started, release: release}
	im := &mockIMAdapter{}
	p := newPusher(nil, im, &mockGate{allow: true}, discardLog()).withExporter(exp)
	p.exportDone = make(chan struct{}, 1)

	begin := time.Now()
	res := p.Push(context.Background(), PushRequest{Message: adapter.UnifiedMessage{Content: "hi"}})
	if elapsed := time.Since(begin); elapsed > 100*time.Millisecond {
		t.Fatalf("Push blocked on the outlet for %v, want non-blocking", elapsed)
	}
	if !res.Pushed || res.Route != RouteIMBridge {
		t.Fatalf("push = %+v, want pushed via IM bridge despite the outlet failure", res)
	}
	select {
	case <-started:
	case <-time.After(2 * time.Second):
		t.Fatal("exporter was never invoked")
	}
	close(release)
	select {
	case <-p.exportDone:
	case <-time.After(2 * time.Second):
		t.Fatal("export hook did not finish")
	}
}

// TestPusherRateLimitedPushIsNotExported 断言被限流的推送绝不
// 到达出口：该钩子只镜像真实的主动发送。
func TestPusherRateLimitedPushIsNotExported(t *testing.T) {
	t.Parallel()
	exp := &mockExporter{delivered: true}
	p := newPusher(nil, &mockIMAdapter{}, &mockGate{allow: false}, discardLog()).withExporter(exp)
	p.exportDone = make(chan struct{}, 1)

	res := p.Push(context.Background(), PushRequest{Message: adapter.UnifiedMessage{Content: "hi"}})
	if res.Route != RouteRateLimited {
		t.Fatalf("route = %q, want rate_limited", res.Route)
	}
	select {
	case <-p.exportDone:
		t.Fatal("rate-limited push should not be exported")
	case <-time.After(50 * time.Millisecond):
	}
	if len(exp.messages()) != 0 {
		t.Fatalf("exported = %+v, want none", exp.messages())
	}
}