package api

import (
	"context"
	"io"
	"net/http"
	"net/http/httptest"
	"net/http/httputil"
	"net/url"
	"strings"
	"sync/atomic"
	"testing"
	"time"
)

func officeTestProxy(t *testing.T, upstream string, officeTimeout time.Duration) *httputil.ReverseProxy {
	t.Helper()
	target, err := url.Parse(upstream)
	if err != nil {
		t.Fatal(err)
	}
	normal := runtimeTransport.Clone()
	office := runtimeOfficeTransport.Clone()
	normal.ResponseHeaderTimeout = 30 * time.Millisecond
	office.ResponseHeaderTimeout = officeTimeout
	t.Cleanup(normal.CloseIdleConnections)
	t.Cleanup(office.CloseIdleConnections)
	proxy := runtimeReverseProxy(target, "/dsh/office-test", "panel.test", "runtime=secret")
	proxy.Transport = runtimeProxyTransport{normal: normal, office: office}
	return proxy
}

func TestRuntimeOfficeTransportDefaults(t *testing.T) {
	if got := runtimeTransport.ResponseHeaderTimeout; got != 20*time.Second {
		t.Errorf("normal timeout = %s, want 20s", got)
	}
	if got := runtimeOfficeTransport.ResponseHeaderTimeout; got != 120*time.Second {
		t.Errorf("office timeout = %s, want 120s", got)
	}
	if runtimeTransport == runtimeOfficeTransport {
		t.Fatal("office transport must be separate")
	}
	target, _ := url.Parse("http://panel.test")
	proxy := runtimeReverseProxy(target, "/dsh/office-test", "panel.test", "")
	transport, ok := proxy.Transport.(runtimeProxyTransport)
	if !ok || transport.normal != runtimeTransport || transport.office != runtimeOfficeTransport {
		t.Fatalf("unexpected default transport: %#v", proxy.Transport)
	}
}

func TestRuntimeOfficeProxyRouting(t *testing.T) {
	for _, path := range []string{
		"/api/officeToPdf/render",
		"/api/status",
		"/api/officeToPdf/render/",
		"/api/officeToPdf/render/child",
		"/api/officeToPdf/renderOther",
		"/api/officetopdf/render",
		"/api/officeToPdf/status",
	} {
		t.Run(path, func(t *testing.T) {
			const body = "document payload"
			const query = "file=report%20one.docx&mode=pdf&mode=preview"
			var calls atomic.Int32
			upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				calls.Add(1)
				data, err := io.ReadAll(r.Body)
				if err != nil || string(data) != body || r.Method != http.MethodPost {
					t.Errorf("upstream method/body = %s %q, error %v", r.Method, data, err)
				}
				if r.URL.Path != path || r.URL.RawQuery != query {
					t.Errorf("upstream URL = %s", r.URL)
				}
				if r.Host != "panel.test" || r.Header.Get("X-Forwarded-Prefix") != "/dsh/office-test" || r.Header.Get("Cookie") != "runtime=secret" {
					t.Errorf("upstream host/headers = %s %v", r.Host, r.Header)
				}
				time.Sleep(100 * time.Millisecond)
				w.Header().Set("Content-Type", "application/pdf")
				_, _ = io.WriteString(w, "rendered PDF")
			}))
			defer upstream.Close()
			proxy := officeTestProxy(t, upstream.URL, 500*time.Millisecond)
			req := httptest.NewRequest(http.MethodPost, "/dsh/office-test"+path+"?"+query+"&token=removed", strings.NewReader(body))
			req.Header.Set("Cookie", "panel=private")
			originalURL := req.URL.String()
			w := httptest.NewRecorder()
			proxy.ServeHTTP(w, req)
			want := http.StatusBadGateway
			if path == "/api/officeToPdf/render" {
				want = http.StatusOK
				if w.Body.String() != "rendered PDF" {
					t.Errorf("response body = %q", w.Body.String())
				}
			}
			if w.Code != want {
				t.Errorf("status = %d, want %d: %s", w.Code, want, w.Body.String())
			}
			if req.URL.String() != originalURL || req.Header.Get("Cookie") != "panel=private" {
				t.Error("proxy mutated incoming URL or cookies")
			}
			upstream.Close()
			if got := calls.Load(); got != 1 {
				t.Errorf("mutating request sent %d times, want exactly once", got)
			}
		})
	}
}

func TestRuntimeOfficeProxyFiniteTimeoutAndCancellation(t *testing.T) {
	for _, name := range []string{"header timeout", "caller cancellation"} {
		t.Run(name, func(t *testing.T) {
			started := make(chan struct{}, 2)
			canceled := make(chan struct{}, 2)
			var calls atomic.Int32
			upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				calls.Add(1)
				_, _ = io.Copy(io.Discard, r.Body)
				started <- struct{}{}
				select {
				case <-r.Context().Done():
					canceled <- struct{}{}
				case <-time.After(2 * time.Second):
				}
			}))
			defer upstream.Close()
			officeTimeout := 100 * time.Millisecond
			if name == "caller cancellation" {
				officeTimeout = 5 * time.Second
			}
			proxy := officeTestProxy(t, upstream.URL, officeTimeout)
			ctx, cancel := context.WithCancel(context.Background())
			defer cancel()
			req := httptest.NewRequest(http.MethodPost, "/dsh/office-test/api/officeToPdf/render?mode=pdf", strings.NewReader("document")).WithContext(ctx)
			w := httptest.NewRecorder()
			done := make(chan struct{})
			go func() {
				proxy.ServeHTTP(w, req)
				close(done)
			}()
			select {
			case <-started:
			case <-time.After(time.Second):
				t.Fatal("request never reached upstream")
			}
			if name == "caller cancellation" {
				cancel()
			}
			select {
			case <-done:
			case <-time.After(500 * time.Millisecond):
				t.Fatal("proxy did not promptly finish")
			}
			if w.Code != http.StatusBadGateway {
				t.Errorf("status = %d, want 502", w.Code)
			}
			select {
			case <-canceled:
			case <-time.After(500 * time.Millisecond):
				t.Fatal("upstream context was not canceled")
			}
			upstream.Close()
			if got := calls.Load(); got != 1 {
				t.Errorf("mutating request sent %d times, want exactly once", got)
			}
		})
	}
}