package web

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"io/fs"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"testing/fstest"
	"time"

	"speedtest/internal/probe"
	recordstore "speedtest/internal/store"
)

func TestRecordsEndpointReturnsRecords(t *testing.T) {
	store := &memoryStore{
		records: []recordstore.Record{
			{
				ID:      "run-2",
				Client:  recordstore.ClientInfo{IP: "203.0.113.20", ISP: "Example Mobile", Region: "Beijing"},
				Summary: probe.Summary{ID: "run-2", Target: "example.org:443", Score: 88},
				Samples: []probe.Sample{{Kind: "tcp", Success: true, LatencyMS: 40}},
			},
			{
				ID:      "run-1",
				Client:  recordstore.ClientInfo{IP: "198.51.100.10", ISP: "Example Telecom", Region: "Shanghai"},
				Summary: probe.Summary{ID: "run-1", Target: "example.com:80", Score: 95},
				Samples: []probe.Sample{{Kind: "tcp", Success: true, LatencyMS: 30}},
			},
		},
	}
	server := New(Options{Store: store})

	req := httptest.NewRequest(http.MethodGet, "/api/records?limit=2", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body=%s", res.Code, res.Body.String())
	}
	var payload recordsResponse
	if err := json.Unmarshal(res.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if len(payload.Records) != 2 {
		t.Fatalf("len(records) = %d, want 2", len(payload.Records))
	}
	if payload.Records[0].ID != "run-2" {
		t.Fatalf("first record id = %q, want run-2", payload.Records[0].ID)
	}
	if payload.Records[0].Client.IP != "203.0.113.*" || payload.Records[0].Client.ISP != "Example Mobile" {
		t.Fatalf("first record client = %#v, want anonymized client data", payload.Records[0].Client)
	}
	if len(payload.Records[0].Samples) != 1 {
		t.Fatalf("first record samples = %d, want 1", len(payload.Records[0].Samples))
	}
}

func TestRecordsEndpointAnonymizesClientIPAndFillsMissingISP(t *testing.T) {
	store := &memoryStore{
		records: []recordstore.Record{
			{
				ID:      "run-1",
				Client:  recordstore.ClientInfo{IP: "203.0.113.20", Region: "Beijing"},
				Summary: probe.Summary{ID: "run-1", Target: "example.com:80", Score: 95},
			},
		},
	}
	server := New(Options{Store: store})

	req := httptest.NewRequest(http.MethodGet, "/api/records?limit=1", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body=%s", res.Code, res.Body.String())
	}
	var payload recordsResponse
	if err := json.Unmarshal(res.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode response: %v", err)
	}
	client := payload.Records[0].Client
	if client.IP != "203.0.113.*" {
		t.Fatalf("client IP = %q, want anonymized 203.0.113.*", client.IP)
	}
	if client.ISP != "未知运营商" {
		t.Fatalf("client ISP = %q, want 未知运营商", client.ISP)
	}
}

func TestConfigEndpointReturnsBandwidthLimit(t *testing.T) {
	server := New(Options{Store: &memoryStore{}, BandwidthLimitMbps: 80})

	req := httptest.NewRequest(http.MethodGet, "/api/config", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body=%s", res.Code, res.Body.String())
	}
	var payload configResponse
	if err := json.Unmarshal(res.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if payload.BandwidthLimitMbps != 80 {
		t.Fatalf("BandwidthLimitMbps = %.2f, want 80", payload.BandwidthLimitMbps)
	}
	if payload.BandwidthLimitLabel != "80 Mbps" {
		t.Fatalf("BandwidthLimitLabel = %q, want 80 Mbps", payload.BandwidthLimitLabel)
	}
}

func TestHealthEventsStreamsHeartbeat(t *testing.T) {
	server := New(Options{Store: &memoryStore{}, BandwidthLimitMbps: 30})

	req := httptest.NewRequest(http.MethodGet, "/api/health/events?limit=1", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body=%s", res.Code, res.Body.String())
	}
	if contentType := res.Header().Get("Content-Type"); !strings.HasPrefix(contentType, "text/event-stream") {
		t.Fatalf("Content-Type = %q, want text/event-stream", contentType)
	}
	body := res.Body.String()
	if !strings.Contains(body, "event: heartbeat") || !strings.Contains(body, `"bandwidthLimitLabel":"30 Mbps"`) {
		t.Fatalf("heartbeat body = %q, want heartbeat with bandwidth label", body)
	}
}

func TestDownloadEndpointStreamsRequestedBytesAndAdvertisesLimit(t *testing.T) {
	server := New(Options{Store: &memoryStore{}, BandwidthLimitMbps: 80})

	createReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":1}`))
	createRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(createRes, createReq)
	if createRes.Code != http.StatusAccepted {
		t.Fatalf("create status = %d, want 202; body=%s", createRes.Code, createRes.Body.String())
	}
	var created createTestResponse
	if err := json.Unmarshal(createRes.Body.Bytes(), &created); err != nil {
		t.Fatalf("decode create response: %v", err)
	}

	req := httptest.NewRequest(http.MethodGet, created.DownloadURL+"&bytes=1024", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body=%s", res.Code, res.Body.String())
	}
	if res.Body.Len() != 1024 {
		t.Fatalf("download length = %d, want 1024", res.Body.Len())
	}
	if got := res.Header().Get("X-NetStable-Bandwidth-Limit-Mbps"); got != "80" {
		t.Fatalf("limit header = %q, want 80", got)
	}
}

func TestDownloadEndpointRequiresActiveTestID(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	req := httptest.NewRequest(http.MethodGet, "/api/download?bytes=1024", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusConflict {
		t.Fatalf("status = %d, want 409; body=%s", res.Code, res.Body.String())
	}
}

func TestUploadEndpointAcceptsActiveSession(t *testing.T) {
	server := New(Options{Store: &memoryStore{}, BandwidthLimitMbps: 80})

	createReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":1}`))
	createRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(createRes, createReq)
	if createRes.Code != http.StatusAccepted {
		t.Fatalf("create status = %d, want 202; body=%s", createRes.Code, createRes.Body.String())
	}
	var created createTestResponse
	if err := json.Unmarshal(createRes.Body.Bytes(), &created); err != nil {
		t.Fatalf("decode create response: %v", err)
	}

	req := httptest.NewRequest(http.MethodPost, created.UploadURL, bytes.NewBuffer(make([]byte, 2048)))
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body=%s", res.Code, res.Body.String())
	}
	var payload transferResponse
	if err := json.Unmarshal(res.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode upload response: %v", err)
	}
	if payload.Bytes != 2048 {
		t.Fatalf("uploaded bytes = %d, want 2048", payload.Bytes)
	}
}

func TestUploadEndpointRequiresActiveTestID(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	req := httptest.NewRequest(http.MethodPost, "/api/upload?bytes=1024", bytes.NewBuffer(make([]byte, 1024)))
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusConflict {
		t.Fatalf("status = %d, want 409; body=%s", res.Code, res.Body.String())
	}
}

func TestDownloadEndpointRejectsInvalidByteCount(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	req := httptest.NewRequest(http.MethodGet, "/api/download?bytes=0", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400; body=%s", res.Code, res.Body.String())
	}
}

func TestCreateTestRejectsInvalidTarget(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	req := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com:abc"}`))
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400; body=%s", res.Code, res.Body.String())
	}
	if !strings.Contains(res.Body.String(), "invalid target") {
		t.Fatalf("body = %q, want invalid target error", res.Body.String())
	}
}

func TestClientIPUsesRemoteAddrUnlessProxyHeadersAreTrusted(t *testing.T) {
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.RemoteAddr = "198.51.100.10:54321"
	req.Header.Set("X-Forwarded-For", "203.0.113.20")
	req.Header.Set("X-Real-IP", "203.0.113.30")

	if got := clientIPFromRequest(req, false); got != "198.51.100.10" {
		t.Fatalf("clientIPFromRequest untrusted = %q, want RemoteAddr IP", got)
	}
	if got := clientIPFromRequest(req, true); got != "203.0.113.30" {
		t.Fatalf("clientIPFromRequest trusted = %q, want X-Real-IP", got)
	}
}

func TestCreateTestReturnsSessionIDAndRouteURLs(t *testing.T) {
	server := New(Options{Store: &memoryStore{}, ClientResolver: staticResolver})

	req := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":1,"intervalMillis":200,"timeoutMillis":300}`))
	req.RemoteAddr = "198.51.100.10:54321"
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusAccepted {
		t.Fatalf("status = %d, want 202; body=%s", res.Code, res.Body.String())
	}
	var payload createTestResponse
	if err := json.Unmarshal(res.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if payload.ID == "" {
		t.Fatal("payload.ID is empty")
	}
	if payload.Status != "ready" || payload.QueuePosition != 0 || payload.QueueURL != "/api/tests/"+payload.ID+"/queue" {
		t.Fatalf("queue fields = %q/%d/%q, want ready/0/queue URL", payload.Status, payload.QueuePosition, payload.QueueURL)
	}
	if payload.DownloadURL != "/api/download?testId="+payload.ID {
		t.Fatalf("DownloadURL = %q, want /api/download?testId=%s", payload.DownloadURL, payload.ID)
	}
	if payload.UploadURL != "/api/upload?testId="+payload.ID {
		t.Fatalf("UploadURL = %q, want /api/upload?testId=%s", payload.UploadURL, payload.ID)
	}
	if payload.CompleteURL != "/api/tests/"+payload.ID+"/complete" {
		t.Fatalf("CompleteURL = %q, want /api/tests/%s/complete", payload.CompleteURL, payload.ID)
	}
	if payload.CancelURL != "/api/tests/"+payload.ID+"/cancel" {
		t.Fatalf("CancelURL = %q, want /api/tests/%s/cancel", payload.CancelURL, payload.ID)
	}
}

func TestCreateTestQueuesWhenAnotherSessionIsActive(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	firstReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":1}`))
	firstRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(firstRes, firstReq)
	if firstRes.Code != http.StatusAccepted {
		t.Fatalf("first status = %d, want 202; body=%s", firstRes.Code, firstRes.Body.String())
	}

	secondReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.org","durationSeconds":1}`))
	secondRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(secondRes, secondReq)
	if secondRes.Code != http.StatusAccepted {
		t.Fatalf("second status = %d, want 202 queued; body=%s", secondRes.Code, secondRes.Body.String())
	}
	var queued createTestResponse
	if err := json.Unmarshal(secondRes.Body.Bytes(), &queued); err != nil {
		t.Fatalf("decode queued response: %v", err)
	}
	if queued.Status != "queued" || queued.QueuePosition != 1 || queued.QueueURL != "/api/tests/"+queued.ID+"/queue" {
		t.Fatalf("queued response = %#v, want queued at position 1", queued)
	}
}

func TestQueuedTestPromotesAfterActiveSessionCompletes(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	firstReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":1}`))
	firstRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(firstRes, firstReq)
	if firstRes.Code != http.StatusAccepted {
		t.Fatalf("first status = %d, want 202; body=%s", firstRes.Code, firstRes.Body.String())
	}
	var first createTestResponse
	if err := json.Unmarshal(firstRes.Body.Bytes(), &first); err != nil {
		t.Fatalf("decode first response: %v", err)
	}

	secondReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.org","durationSeconds":1}`))
	secondRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(secondRes, secondReq)
	if secondRes.Code != http.StatusAccepted {
		t.Fatalf("second status = %d, want 202; body=%s", secondRes.Code, secondRes.Body.String())
	}
	var second createTestResponse
	if err := json.Unmarshal(secondRes.Body.Bytes(), &second); err != nil {
		t.Fatalf("decode second response: %v", err)
	}
	if second.Status != "queued" || second.QueuePosition != 1 {
		t.Fatalf("second = %#v, want queued position 1", second)
	}

	queueReq := httptest.NewRequest(http.MethodGet, second.QueueURL, nil)
	queueRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(queueRes, queueReq)
	if queueRes.Code != http.StatusOK {
		t.Fatalf("queue status = %d, want 200; body=%s", queueRes.Code, queueRes.Body.String())
	}
	var queued queueStatusResponse
	if err := json.Unmarshal(queueRes.Body.Bytes(), &queued); err != nil {
		t.Fatalf("decode queue status: %v", err)
	}
	if queued.Status != "queued" || queued.QueuePosition != 1 {
		t.Fatalf("queue status = %#v, want queued position 1", queued)
	}

	completeReq := httptest.NewRequest(http.MethodPost, first.CompleteURL, jsonBody(`{"samples":[]}`))
	completeRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(completeRes, completeReq)
	if completeRes.Code != http.StatusOK {
		t.Fatalf("complete status = %d, want 200; body=%s", completeRes.Code, completeRes.Body.String())
	}

	readyReq := httptest.NewRequest(http.MethodGet, second.QueueURL, nil)
	readyRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(readyRes, readyReq)
	if readyRes.Code != http.StatusOK {
		t.Fatalf("ready status = %d, want 200; body=%s", readyRes.Code, readyRes.Body.String())
	}
	var ready queueStatusResponse
	if err := json.Unmarshal(readyRes.Body.Bytes(), &ready); err != nil {
		t.Fatalf("decode ready status: %v", err)
	}
	if ready.Status != "ready" || ready.QueuePosition != 0 {
		t.Fatalf("ready status = %#v, want ready position 0", ready)
	}

	downloadReq := httptest.NewRequest(http.MethodGet, second.DownloadURL+"&bytes=16", nil)
	downloadRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(downloadRes, downloadReq)
	if downloadRes.Code != http.StatusOK || downloadRes.Body.Len() != 16 {
		t.Fatalf("download status/body = %d/%d, want 200/16; body=%s", downloadRes.Code, downloadRes.Body.Len(), downloadRes.Body.String())
	}
}

func TestCancelActiveTestPromotesQueuedSession(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	firstReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":30}`))
	firstRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(firstRes, firstReq)
	if firstRes.Code != http.StatusAccepted {
		t.Fatalf("first status = %d, want 202; body=%s", firstRes.Code, firstRes.Body.String())
	}
	var first createTestResponse
	if err := json.Unmarshal(firstRes.Body.Bytes(), &first); err != nil {
		t.Fatalf("decode first response: %v", err)
	}

	secondReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.org","durationSeconds":1}`))
	secondRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(secondRes, secondReq)
	if secondRes.Code != http.StatusAccepted {
		t.Fatalf("second status = %d, want 202; body=%s", secondRes.Code, secondRes.Body.String())
	}
	var second createTestResponse
	if err := json.Unmarshal(secondRes.Body.Bytes(), &second); err != nil {
		t.Fatalf("decode second response: %v", err)
	}
	if second.Status != "queued" {
		t.Fatalf("second status = %q, want queued", second.Status)
	}

	cancelReq := httptest.NewRequest(http.MethodPost, first.CancelURL, nil)
	cancelRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(cancelRes, cancelReq)
	if cancelRes.Code != http.StatusOK {
		t.Fatalf("cancel status = %d, want 200; body=%s", cancelRes.Code, cancelRes.Body.String())
	}

	queueReq := httptest.NewRequest(http.MethodGet, second.QueueURL, nil)
	queueRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(queueRes, queueReq)
	if queueRes.Code != http.StatusOK {
		t.Fatalf("queue status = %d, want 200; body=%s", queueRes.Code, queueRes.Body.String())
	}
	var ready queueStatusResponse
	if err := json.Unmarshal(queueRes.Body.Bytes(), &ready); err != nil {
		t.Fatalf("decode queue status: %v", err)
	}
	if ready.Status != "ready" || ready.QueuePosition != 0 {
		t.Fatalf("queue status = %#v, want promoted ready session", ready)
	}
}

func TestCancelQueuedTestRemovesItAndUpdatesPositions(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	firstReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":30}`))
	firstRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(firstRes, firstReq)
	if firstRes.Code != http.StatusAccepted {
		t.Fatalf("first status = %d, want 202; body=%s", firstRes.Code, firstRes.Body.String())
	}

	secondReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.org","durationSeconds":1}`))
	secondRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(secondRes, secondReq)
	if secondRes.Code != http.StatusAccepted {
		t.Fatalf("second status = %d, want 202; body=%s", secondRes.Code, secondRes.Body.String())
	}
	var second createTestResponse
	if err := json.Unmarshal(secondRes.Body.Bytes(), &second); err != nil {
		t.Fatalf("decode second response: %v", err)
	}

	thirdReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.net","durationSeconds":1}`))
	thirdRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(thirdRes, thirdReq)
	if thirdRes.Code != http.StatusAccepted {
		t.Fatalf("third status = %d, want 202; body=%s", thirdRes.Code, thirdRes.Body.String())
	}
	var third createTestResponse
	if err := json.Unmarshal(thirdRes.Body.Bytes(), &third); err != nil {
		t.Fatalf("decode third response: %v", err)
	}
	if third.QueuePosition != 2 {
		t.Fatalf("third position = %d, want 2 before cancel", third.QueuePosition)
	}

	cancelReq := httptest.NewRequest(http.MethodPost, second.CancelURL, nil)
	cancelRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(cancelRes, cancelReq)
	if cancelRes.Code != http.StatusOK {
		t.Fatalf("cancel status = %d, want 200; body=%s", cancelRes.Code, cancelRes.Body.String())
	}

	secondQueueReq := httptest.NewRequest(http.MethodGet, second.QueueURL, nil)
	secondQueueRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(secondQueueRes, secondQueueReq)
	if secondQueueRes.Code != http.StatusNotFound {
		t.Fatalf("canceled queue status = %d, want 404; body=%s", secondQueueRes.Code, secondQueueRes.Body.String())
	}

	thirdQueueReq := httptest.NewRequest(http.MethodGet, third.QueueURL, nil)
	thirdQueueRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(thirdQueueRes, thirdQueueReq)
	if thirdQueueRes.Code != http.StatusOK {
		t.Fatalf("third queue status = %d, want 200; body=%s", thirdQueueRes.Code, thirdQueueRes.Body.String())
	}
	var queued queueStatusResponse
	if err := json.Unmarshal(thirdQueueRes.Body.Bytes(), &queued); err != nil {
		t.Fatalf("decode third queue status: %v", err)
	}
	if queued.Status != "queued" || queued.QueuePosition != 1 {
		t.Fatalf("third queue status = %#v, want queued position 1 after cancel", queued)
	}
}

func TestCreateIperf3SessionStartsOneOffServerAndUsesGlobalLock(t *testing.T) {
	server := New(Options{Store: &memoryStore{}, Iperf3Path: fakeIperf3(t)})

	req := httptest.NewRequest(http.MethodPost, "/api/iperf3/sessions", jsonBody(`{"durationSeconds":1,"protocol":"tcp"}`))
	req.RemoteAddr = "203.0.113.20:54321"
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusAccepted {
		t.Fatalf("status = %d, want 202; body=%s", res.Code, res.Body.String())
	}
	var payload createIperf3Response
	if err := json.Unmarshal(res.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if payload.ID == "" || payload.Port < 20000 || payload.CompleteURL != "/api/iperf3/sessions/"+payload.ID+"/complete" {
		t.Fatalf("payload = %#v, want id, random high port, and complete URL", payload)
	}

	secondReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.org","durationSeconds":1}`))
	secondRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(secondRes, secondReq)
	if secondRes.Code != http.StatusAccepted {
		t.Fatalf("second status = %d, want 202 queued while iperf3 session is active; body=%s", secondRes.Code, secondRes.Body.String())
	}
	var queued createTestResponse
	if err := json.Unmarshal(secondRes.Body.Bytes(), &queued); err != nil {
		t.Fatalf("decode queued response: %v", err)
	}
	if queued.Status != "queued" || queued.QueuePosition != 1 {
		t.Fatalf("queued response = %#v, want queued position 1", queued)
	}
}

func TestCompleteIperf3SessionPersistsRecordAndReleasesLock(t *testing.T) {
	store := &memoryStore{}
	server := New(Options{Store: store, Iperf3Path: fakeIperf3(t), ClientResolver: staticResolver})

	createReq := httptest.NewRequest(http.MethodPost, "/api/iperf3/sessions", jsonBody(`{"durationSeconds":1,"protocol":"tcp","reverse":true}`))
	createReq.RemoteAddr = "203.0.113.20:54321"
	createRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(createRes, createReq)
	if createRes.Code != http.StatusAccepted {
		t.Fatalf("create status = %d, want 202; body=%s", createRes.Code, createRes.Body.String())
	}
	var created createIperf3Response
	if err := json.Unmarshal(createRes.Body.Bytes(), &created); err != nil {
		t.Fatalf("decode create response: %v", err)
	}

	body := `{
		"startedAt":"2026-06-06T01:00:00Z",
		"finishedAt":"2026-06-06T01:00:01Z",
		"samples":[{"at":"2026-06-06T01:00:01Z","kind":"download","success":true,"bytes":1048576,"mbps":88.5}]
	}`
	completeReq := httptest.NewRequest(http.MethodPost, created.CompleteURL, jsonBody(body))
	completeRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(completeRes, completeReq)
	if completeRes.Code != http.StatusOK {
		t.Fatalf("complete status = %d, want 200; body=%s", completeRes.Code, completeRes.Body.String())
	}
	var completed completeTestResponse
	if err := json.Unmarshal(completeRes.Body.Bytes(), &completed); err != nil {
		t.Fatalf("decode complete response: %v", err)
	}
	if completed.Summary.AvgDownloadMbps != 88.5 || !strings.Contains(completed.Summary.Target, "iperf3/tcp") {
		t.Fatalf("summary = %#v, want iperf3 download summary", completed.Summary)
	}

	records := store.snapshot()
	if len(records) != 1 || records[0].Client.IP != "203.0.113.*" || len(records[0].Samples) != 1 {
		t.Fatalf("records = %#v, want one persisted iperf3 record with anonymized client", records)
	}

	nextReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.org","durationSeconds":1}`))
	nextRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(nextRes, nextReq)
	if nextRes.Code != http.StatusAccepted {
		t.Fatalf("next status = %d, want 202 after iperf3 completion releases lock; body=%s", nextRes.Code, nextRes.Body.String())
	}
}

func TestBrowserSessionQueuesDuringDownloadAndUploadWindows(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	firstReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":30}`))
	firstRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(firstRes, firstReq)
	if firstRes.Code != http.StatusAccepted {
		t.Fatalf("first status = %d, want 202; body=%s", firstRes.Code, firstRes.Body.String())
	}

	server.mu.Lock()
	request := server.sessions[server.activeID]
	request.CreatedAt = time.Now().UTC().Add(-90 * time.Second)
	server.sessions[server.activeID] = request
	server.mu.Unlock()

	secondReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.org","durationSeconds":1}`))
	secondRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(secondRes, secondReq)
	if secondRes.Code != http.StatusAccepted {
		t.Fatalf("second status = %d, want 202 queued while 30s download + 30s upload window is active; body=%s", secondRes.Code, secondRes.Body.String())
	}
	var queued createTestResponse
	if err := json.Unmarshal(secondRes.Body.Bytes(), &queued); err != nil {
		t.Fatalf("decode queued response: %v", err)
	}
	if queued.Status != "queued" || queued.QueuePosition != 1 {
		t.Fatalf("queued response = %#v, want queued position 1", queued)
	}
}

func TestEventsEndpointIsRemoved(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	createReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":1}`))
	createRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(createRes, createReq)
	if createRes.Code != http.StatusAccepted {
		t.Fatalf("create status = %d, want 202; body=%s", createRes.Code, createRes.Body.String())
	}
	var created createTestResponse
	if err := json.Unmarshal(createRes.Body.Bytes(), &created); err != nil {
		t.Fatalf("decode create response: %v", err)
	}
	if strings.Contains(createRes.Body.String(), "eventsUrl") {
		t.Fatalf("create response should not advertise an events URL: %s", createRes.Body.String())
	}

	eventsReq := httptest.NewRequest(http.MethodGet, "/api/tests/"+created.ID+"/events", nil)
	eventsRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(eventsRes, eventsReq)
	if eventsRes.Code != http.StatusNotFound {
		t.Fatalf("events status = %d, want 404 now that the SSE endpoint is removed; body=%s", eventsRes.Code, eventsRes.Body.String())
	}
}

func TestCompleteEndpointPersistsBrowserSpeedRecordAndReleasesLock(t *testing.T) {
	store := &memoryStore{}
	server := New(Options{Store: store, ClientResolver: staticResolver})

	createReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":30}`))
	createReq.RemoteAddr = "203.0.113.20:54321"
	createRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(createRes, createReq)
	if createRes.Code != http.StatusAccepted {
		t.Fatalf("create status = %d, want 202; body=%s", createRes.Code, createRes.Body.String())
	}
	var created createTestResponse
	if err := json.Unmarshal(createRes.Body.Bytes(), &created); err != nil {
		t.Fatalf("decode create response: %v", err)
	}

	body := `{
		"startedAt":"2026-06-05T08:00:00Z",
		"finishedAt":"2026-06-05T08:00:05Z",
		"samples":[
			{"at":"2026-06-05T08:00:01Z","kind":"latency","success":true,"latencyMs":20},
			{"at":"2026-06-05T08:00:02Z","kind":"download","success":true,"bytes":4194304,"mbps":75.5},
			{"at":"2026-06-05T08:00:03Z","kind":"upload","success":true,"bytes":2097152,"mbps":42.25}
		]
	}`
	completeReq := httptest.NewRequest(http.MethodPost, created.CompleteURL, jsonBody(body))
	completeRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(completeRes, completeReq)
	if completeRes.Code != http.StatusOK {
		t.Fatalf("complete status = %d, want 200; body=%s", completeRes.Code, completeRes.Body.String())
	}
	var completed completeTestResponse
	if err := json.Unmarshal(completeRes.Body.Bytes(), &completed); err != nil {
		t.Fatalf("decode complete response: %v", err)
	}
	if completed.Summary.AvgDownloadMbps != 75.5 || completed.Summary.AvgUploadMbps != 42.25 {
		t.Fatalf("summary speeds = %.2f/%.2f, want 75.5/42.25", completed.Summary.AvgDownloadMbps, completed.Summary.AvgUploadMbps)
	}

	records := store.snapshot()
	if len(records) != 1 {
		t.Fatalf("records = %d, want 1", len(records))
	}
	if records[0].Client.IP != "203.0.113.*" {
		t.Fatalf("record client IP = %q, want 203.0.113.*", records[0].Client.IP)
	}
	if len(records[0].Samples) != 3 {
		t.Fatalf("record samples = %d, want 3", len(records[0].Samples))
	}

	nextReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.org","durationSeconds":1}`))
	nextRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(nextRes, nextReq)
	if nextRes.Code != http.StatusAccepted {
		t.Fatalf("next status = %d, want 202 after complete releases lock; body=%s", nextRes.Code, nextRes.Body.String())
	}
}

func TestCompleteEndpointAcceptsLargeSamplePayload(t *testing.T) {
	store := &memoryStore{}
	server := New(Options{Store: store, ClientResolver: staticResolver})

	createReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":30}`))
	createReq.RemoteAddr = "203.0.113.20:54321"
	createRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(createRes, createReq)
	if createRes.Code != http.StatusAccepted {
		t.Fatalf("create status = %d, want 202; body=%s", createRes.Code, createRes.Body.String())
	}
	var created createTestResponse
	if err := json.Unmarshal(createRes.Body.Bytes(), &created); err != nil {
		t.Fatalf("decode create response: %v", err)
	}

	completeReq := httptest.NewRequest(http.MethodPost, created.CompleteURL, largeCompleteBody(t, 30000))
	completeRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(completeRes, completeReq)
	if completeRes.Code != http.StatusOK {
		t.Fatalf("complete status = %d, want 200 for large sample payload; body=%s", completeRes.Code, completeRes.Body.String())
	}
	records := store.snapshot()
	if len(records) != 1 || len(records[0].Samples) != 30000 {
		t.Fatalf("records = %d samples=%d, want one record with 30000 samples", len(records), len(records[0].Samples))
	}
}

func TestCompleteEndpointCanRetryWhenPersistFails(t *testing.T) {
	store := &flakyStore{fail: true}
	server := New(Options{Store: store, ClientResolver: staticResolver})

	createReq := httptest.NewRequest(http.MethodPost, "/api/tests", jsonBody(`{"target":"example.com","durationSeconds":30}`))
	createReq.RemoteAddr = "203.0.113.20:54321"
	createRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(createRes, createReq)
	if createRes.Code != http.StatusAccepted {
		t.Fatalf("create status = %d, want 202; body=%s", createRes.Code, createRes.Body.String())
	}
	var created createTestResponse
	if err := json.Unmarshal(createRes.Body.Bytes(), &created); err != nil {
		t.Fatalf("decode create response: %v", err)
	}

	firstComplete := httptest.NewRequest(http.MethodPost, created.CompleteURL, jsonBody(`{"samples":[{"kind":"download","success":true,"bytes":1024,"mbps":10}]}`))
	firstRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(firstRes, firstComplete)
	if firstRes.Code != http.StatusInternalServerError {
		t.Fatalf("first complete status = %d, want 500; body=%s", firstRes.Code, firstRes.Body.String())
	}

	store.fail = false
	secondComplete := httptest.NewRequest(http.MethodPost, created.CompleteURL, jsonBody(`{"samples":[{"kind":"download","success":true,"bytes":1024,"mbps":10}]}`))
	secondRes := httptest.NewRecorder()
	server.Handler().ServeHTTP(secondRes, secondComplete)
	if secondRes.Code != http.StatusOK {
		t.Fatalf("retry complete status = %d, want 200 after store recovers; body=%s", secondRes.Code, secondRes.Body.String())
	}
	if records := store.snapshot(); len(records) != 1 {
		t.Fatalf("records = %d, want one record after retry", len(records))
	}
}

func TestBrowserSummaryUsesSustainedTransferRatesForMax(t *testing.T) {
	start := time.Date(2026, 6, 10, 8, 0, 0, 0, time.UTC)
	request := TestRequest{
		ID:        "test-1",
		Target:    probe.Target{Address: "example.com:443"},
		CreatedAt: start,
	}
	raw := completeTestRequest{
		StartedAt:  start,
		FinishedAt: start.Add(5 * time.Second),
		Samples: []probe.Sample{
			{At: start.Add(1 * time.Second), Kind: "download", Success: true, LatencyMS: 1000, Bytes: 5_000_000, Mbps: 40},
			{At: start.Add(2 * time.Second), Kind: "download", Success: true, LatencyMS: 1000, Bytes: 5_000_000, Mbps: 1000},
			{At: start.Add(3 * time.Second), Kind: "download", Success: true, LatencyMS: 1000, Bytes: 5_000_000, Mbps: 40},
			{At: start.Add(4 * time.Second), Kind: "download", Success: true, LatencyMS: 1000, Bytes: 5_000_000, Mbps: 40},
		},
	}

	summary := summarizeBrowserSamples(request, raw)

	if summary.AvgDownloadMbps != 40 {
		t.Fatalf("AvgDownloadMbps = %.2f, want sustained 40 Mbps", summary.AvgDownloadMbps)
	}
	if summary.MaxDownloadMbps != 40 {
		t.Fatalf("MaxDownloadMbps = %.2f, want sustained 40 Mbps instead of single-sample spike", summary.MaxDownloadMbps)
	}
}

func TestBrowserSummaryDoesNotTreatShortBurstsAsSustainedMax(t *testing.T) {
	start := time.Date(2026, 6, 10, 8, 0, 0, 0, time.UTC)
	var samples []probe.Sample
	elapsed := time.Duration(0)
	for i := 0; i < 10; i++ {
		latency := 50 * time.Millisecond
		mbps := 671.09
		if i%2 == 1 {
			latency = 1750 * time.Millisecond
			mbps = 19.17
		}
		elapsed += latency
		samples = append(samples, probe.Sample{
			At:        start.Add(elapsed),
			Kind:      "download",
			Success:   true,
			LatencyMS: float64(latency.Milliseconds()),
			Bytes:     4 * 1024 * 1024,
			Mbps:      mbps,
		})
	}
	request := TestRequest{
		ID:        "test-1",
		Target:    probe.Target{Address: "example.com:443"},
		CreatedAt: start,
	}
	raw := completeTestRequest{
		StartedAt:  start,
		FinishedAt: start.Add(elapsed),
		Samples:    samples,
	}

	summary := summarizeBrowserSamples(request, raw)

	if summary.MaxDownloadMbps > 60 {
		t.Fatalf("MaxDownloadMbps = %.2f, want sustained max below short burst rates", summary.MaxDownloadMbps)
	}
	if summary.AvgDownloadMbps < 35 || summary.AvgDownloadMbps > 39 {
		t.Fatalf("AvgDownloadMbps = %.2f, want long-run average around 37 Mbps", summary.AvgDownloadMbps)
	}
}

func TestSSEUnknownSessionReturnsNotFound(t *testing.T) {
	server := New(Options{Store: &memoryStore{}})

	req := httptest.NewRequest(http.MethodGet, "/api/tests/missing/events", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusNotFound {
		t.Fatalf("status = %d, want 404", res.Code)
	}
}

func TestHandlerServesStaticFilesFromFS(t *testing.T) {
	staticFS := http.FS(fstest.MapFS{
		"index.html": &fstest.MapFile{Data: []byte("<html>dashboard</html>")},
	})
	server := New(Options{Store: &memoryStore{}, StaticFS: staticFS})

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body=%s", res.Code, res.Body.String())
	}
	if !strings.Contains(res.Body.String(), "dashboard") {
		t.Fatalf("body = %q, want dashboard content", res.Body.String())
	}
}

func TestDownloadsEndpointServesPackagedLinuxBinary(t *testing.T) {
	downloadsDir := t.TempDir()
	packagePath := filepath.Join(downloadsDir, "netstable-linux-amd64.tar.gz")
	if err := os.WriteFile(packagePath, []byte("fake-package"), 0644); err != nil {
		t.Fatalf("write fake package: %v", err)
	}
	server := New(Options{Store: &memoryStore{}, DownloadsDir: downloadsDir})

	req := httptest.NewRequest(http.MethodGet, "/downloads/netstable-linux-amd64.tar.gz", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body=%s", res.Code, res.Body.String())
	}
	if res.Body.String() != "fake-package" {
		t.Fatalf("body = %q, want fake package", res.Body.String())
	}
	if !strings.Contains(res.Header().Get("Content-Disposition"), "netstable-linux-amd64.tar.gz") {
		t.Fatalf("Content-Disposition = %q, want filename", res.Header().Get("Content-Disposition"))
	}
}

func TestDownloadsEndpointRejectsUnknownBinaryName(t *testing.T) {
	server := New(Options{Store: &memoryStore{}, DownloadsDir: t.TempDir()})

	req := httptest.NewRequest(http.MethodGet, "/downloads/netstable-linux-riscv64", nil)
	res := httptest.NewRecorder()
	server.Handler().ServeHTTP(res, req)

	if res.Code != http.StatusNotFound {
		t.Fatalf("status = %d, want 404", res.Code)
	}
}

func TestSubFSHelperReturnsStaticRoot(t *testing.T) {
	staticFS := fstest.MapFS{
		"static/index.html": &fstest.MapFile{Data: []byte("<html>embedded</html>")},
	}
	root, err := fs.Sub(staticFS, "static")
	if err != nil {
		t.Fatalf("fs.Sub: %v", err)
	}
	if _, err := root.Open("index.html"); err != nil {
		t.Fatalf("open index from sub fs: %v", err)
	}
}

func jsonBody(body string) *bytes.Buffer {
	return bytes.NewBufferString(body)
}

func largeCompleteBody(t *testing.T, sampleCount int) *bytes.Buffer {
	t.Helper()
	var buffer bytes.Buffer
	buffer.WriteString(`{"startedAt":"2026-06-05T08:00:00Z","finishedAt":"2026-06-05T08:00:30Z","samples":[`)
	for i := 0; i < sampleCount; i++ {
		if i > 0 {
			buffer.WriteByte(',')
		}
		kind := "download"
		if i%2 == 1 {
			kind = "upload"
		}
		if err := json.NewEncoder(&buffer).Encode(probe.Sample{
			At:        time.Date(2026, 6, 5, 8, 0, 0, 0, time.UTC).Add(time.Duration(i) * time.Millisecond),
			Kind:      kind,
			Success:   true,
			Bytes:     4 * 1024 * 1024,
			Mbps:      42.5,
			LatencyMS: 150,
		}); err != nil {
			t.Fatalf("encode sample: %v", err)
		}
		data := buffer.Bytes()
		if len(data) > 0 && data[len(data)-1] == '\n' {
			buffer.Truncate(len(data) - 1)
		}
	}
	buffer.WriteString(`]}`)
	return &buffer
}

type memoryStore struct {
	mu      sync.Mutex
	records []recordstore.Record
}

func (s *memoryStore) Append(ctx context.Context, record recordstore.Record) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.records = append([]recordstore.Record{record}, s.records...)
	return nil
}

func (s *memoryStore) List(ctx context.Context, limit int) ([]recordstore.Record, error) {
	s.mu.Lock()
	defer s.mu.Unlock()

	if limit < 1 || limit > len(s.records) {
		limit = len(s.records)
	}
	out := make([]recordstore.Record, limit)
	copy(out, s.records[:limit])
	return out, nil
}

func (s *memoryStore) snapshot() []recordstore.Record {
	s.mu.Lock()
	defer s.mu.Unlock()
	out := make([]recordstore.Record, len(s.records))
	copy(out, s.records)
	return out
}

type flakyStore struct {
	memoryStore
	mu   sync.Mutex
	fail bool
}

func (s *flakyStore) Append(ctx context.Context, record recordstore.Record) error {
	s.mu.Lock()
	fail := s.fail
	s.mu.Unlock()
	if fail {
		return errors.New("store unavailable")
	}
	return s.memoryStore.Append(ctx, record)
}

func staticResolver(ctx context.Context, ip string) (recordstore.ClientInfo, error) {
	return recordstore.ClientInfo{
		IP:      ip,
		ISP:     "Example Mobile",
		Region:  "Beijing",
		Country: "China",
		City:    "Beijing",
		ASN:     "AS64512",
		Source:  "test",
	}, nil
}

func fakeIperf3(t *testing.T) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), "iperf3")
	script := `#!/bin/sh
for arg in "$@"; do
  if [ "$arg" = "-s" ]; then
    sleep 10
    exit 0
  fi
done
cat <<'JSON'
{"end":{"sum_sent":{"bytes":1048576,"bits_per_second":88000000},"sum_received":{"bytes":1048576,"bits_per_second":87000000}}}
JSON
`
	if err := os.WriteFile(path, []byte(script), 0755); err != nil {
		t.Fatalf("write fake iperf3: %v", err)
	}
	return path
}