package events

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

	"ukrrs.com/mopac/harness/internal/config"
)

const (
	testRedmineSecret   = "redmine-hook-secret"
	testDiscourseSecret = "discourse-hook-secret"
	testGiteaSecret     = "gitea-hook-secret"
)

// recordingDispatcher captures dispatched events for assertions.
type recordingDispatcher struct {
	mu     sync.Mutex
	events []Event
}

func (d *recordingDispatcher) DispatchEvent(ctx context.Context, ev Event) {
	d.mu.Lock()
	defer d.mu.Unlock()
	d.events = append(d.events, ev)
}

func (d *recordingDispatcher) dispatched() []Event {
	d.mu.Lock()
	defer d.mu.Unlock()
	return append([]Event(nil), d.events...)
}

func newTestServer(t *testing.T) (*Server, *recordingDispatcher, string) {
	t.Helper()
	stateDir := t.TempDir()
	cfg := config.EventsConfig{
		Listen:   ":0",
		StateDir: stateDir,
		Redmine: config.EventSourceConfig{
			SecretRef:    "literal:" + testRedmineSecret,
			SecretHeader: DefaultRedmineSecretHeader,
		},
		Discourse: config.EventSourceConfig{
			SecretRef:    "literal:" + testDiscourseSecret,
			SecretHeader: DefaultDiscourseSecretHeader,
		},
		Gitea: config.EventSourceConfig{
			SecretRef: "literal:" + testGiteaSecret,
		},
	}
	disp := &recordingDispatcher{}
	srv, err := NewServer(cfg, disp, io.Discard)
	if err != nil {
		t.Fatalf("NewServer: %v", err)
	}
	t.Cleanup(func() { srv.Close() })
	return srv, disp, stateDir
}

func post(t *testing.T, url string, headers map[string]string, body string) (int, string) {
	t.Helper()
	req, err := http.NewRequest(http.MethodPost, url, strings.NewReader(body))
	if err != nil {
		t.Fatal(err)
	}
	for k, v := range headers {
		req.Header.Set(k, v)
	}
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	b, _ := io.ReadAll(resp.Body)
	return resp.StatusCode, string(b)
}

func readLog(t *testing.T, stateDir string) []string {
	t.Helper()
	data, err := os.ReadFile(filepath.Join(stateDir, "events.jsonl"))
	if os.IsNotExist(err) {
		return nil
	}
	if err != nil {
		t.Fatal(err)
	}
	var lines []string
	for _, ln := range strings.Split(strings.TrimSpace(string(data)), "\n") {
		if ln != "" {
			lines = append(lines, ln)
		}
	}
	return lines
}

func TestServerVerificationEndToEnd(t *testing.T) {
	srv, _, stateDir := newTestServer(t)
	ts := httptest.NewServer(srv.Handler())
	defer ts.Close()

	giteaBody := `{"action":"approved","number":5,"pull_request":{"number":5,"title":"PR"},"repository":{"full_name":"ukrrs/MOPAC"},"sender":{"login":"charles"}}`
	giteaHeaders := func(sig string) map[string]string {
		return map[string]string{
			giteaDeliveryHeader:  "delivery-1",
			giteaSignatureHeader: sig,
			"X-Gitea-Event":      "pull_request",
			"X-Gitea-Event-Type": "pull_request_approved",
		}
	}

	cases := []struct {
		name     string
		path     string
		headers  map[string]string
		body     string
		wantCode int
		wantBody string
	}{
		{"gitea unsigned rejected", "/hooks/gitea", nil, giteaBody, 401, "unverified webhook"},
		{"gitea bad signature rejected", "/hooks/gitea", giteaHeaders(strings.Repeat("ff", 32)), giteaBody, 401, "unverified webhook"},
		{"gitea valid accepted", "/hooks/gitea", giteaHeaders(SignGitea([]byte(giteaBody), testGiteaSecret)), giteaBody, 200, `"status":"stored"`},
		{"redmine unsigned rejected", "/hooks/redmine", nil, `{}`, 401, "unverified webhook"},
		{
			"redmine valid accepted",
			"/hooks/redmine",
			map[string]string{DefaultRedmineSecretHeader: testRedmineSecret},
			`{"event_name":"issue_updated","payload":{"issue":{"id":42,"subject":"Ship"},"user":{"login":"charles"}}}`,
			200, `"status":"stored"`,
		},
		{"discourse wrong secret rejected", "/hooks/discourse", map[string]string{DefaultDiscourseSecretHeader: "nope"}, `{}`, 401, "unverified webhook"},
		{
			"discourse valid accepted",
			"/hooks/discourse",
			map[string]string{DefaultDiscourseSecretHeader: testDiscourseSecret, "X-Discourse-Event": "post_created", "X-Discourse-Event-Id": "42"},
			`{"post":{"id":9,"topic_id":7,"username":"charles","topic_title":"Plan"}}`,
			200, `"status":"stored"`,
		},
		{"gitea malformed body rejected", "/hooks/gitea", giteaHeaders(SignGitea([]byte("not json"), testGiteaSecret)), `not json`, 400, "malformed webhook payload"},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			code, body := post(t, ts.URL+tc.path, tc.headers, tc.body)
			if code != tc.wantCode {
				t.Errorf("code = %d, want %d (body %s)", code, tc.wantCode, body)
			}
			if !strings.Contains(body, tc.wantBody) {
				t.Errorf("body %q does not contain %q", body, tc.wantBody)
			}
			for _, secret := range []string{testRedmineSecret, testDiscourseSecret, testGiteaSecret} {
				if strings.Contains(body, secret) {
					t.Errorf("response body leaks secret: %s", body)
				}
			}
		})
	}

	if lines := readLog(t, stateDir); len(lines) != 3 {
		t.Errorf("event log has %d lines, want 3 (only verified events stored):\n%s",
			len(lines), strings.Join(lines, "\n"))
	}
}

func TestServerDedupAndDispatch(t *testing.T) {
	srv, disp, stateDir := newTestServer(t)
	ts := httptest.NewServer(srv.Handler())
	defer ts.Close()

	body := `{"action":"approved","number":5,"pull_request":{"number":5},"sender":{"login":"charles"}}`
	headers := map[string]string{
		giteaDeliveryHeader:  "delivery-dedup",
		giteaSignatureHeader: SignGitea([]byte(body), testGiteaSecret),
	}

	code, respBody := post(t, ts.URL+"/hooks/gitea", headers, body)
	if code != 200 || !strings.Contains(respBody, `"status":"stored"`) {
		t.Fatalf("first delivery: code=%d body=%s", code, respBody)
	}
	code, respBody = post(t, ts.URL+"/hooks/gitea", headers, body)
	if code != 200 || !strings.Contains(respBody, `"status":"duplicate"`) {
		t.Fatalf("replay: code=%d body=%s", code, respBody)
	}

	if lines := readLog(t, stateDir); len(lines) != 1 {
		t.Errorf("event log has %d lines after replay, want 1", len(lines))
	}
	dispatched := disp.dispatched()
	if len(dispatched) != 1 {
		t.Fatalf("dispatcher ran %d times, want 1 (dupes do not dispatch)", len(dispatched))
	}
	if dispatched[0].Action != ActionPipelineStep {
		t.Errorf("dispatched action = %s, want %s", dispatched[0].Action, ActionPipelineStep)
	}
}

func TestServerIgnoreActionDoesNotDispatch(t *testing.T) {
	srv, disp, stateDir := newTestServer(t)
	ts := httptest.NewServer(srv.Handler())
	defer ts.Close()

	body := `{"action":"opened","number":3,"pull_request":{"number":3},"sender":{"login":"bob"}}`
	headers := map[string]string{
		giteaDeliveryHeader:  "delivery-open",
		giteaSignatureHeader: SignGitea([]byte(body), testGiteaSecret),
	}
	code, respBody := post(t, ts.URL+"/hooks/gitea", headers, body)
	if code != 200 || !strings.Contains(respBody, `"action":"ignore"`) {
		t.Fatalf("opened PR: code=%d body=%s", code, respBody)
	}
	if got := disp.dispatched(); len(got) != 0 {
		t.Errorf("ignore action dispatched %d events, want 0", len(got))
	}
	if lines := readLog(t, stateDir); len(lines) != 1 {
		t.Errorf("ignored events are still stored: %d lines, want 1", len(lines))
	}
}

func TestServerAuxRoutes(t *testing.T) {
	srv, _, _ := newTestServer(t)
	ts := httptest.NewServer(srv.Handler())
	defer ts.Close()

	resp, err := http.Get(ts.URL + "/healthz")
	if err != nil {
		t.Fatal(err)
	}
	resp.Body.Close()
	if resp.StatusCode != 200 {
		t.Errorf("healthz = %d, want 200", resp.StatusCode)
	}

	resp, err = http.Get(ts.URL + "/hooks/gitea")
	if err != nil {
		t.Fatal(err)
	}
	resp.Body.Close()
	if resp.StatusCode != http.StatusMethodNotAllowed {
		t.Errorf("GET /hooks/gitea = %d, want 405", resp.StatusCode)
	}

	code, body := post(t, ts.URL+"/hooks/unknown", nil, `{}`)
	if code != 404 {
		t.Errorf("unknown hook = %d, want 404 (body %s)", code, body)
	}
}

func TestServerRejectsOversizedBody(t *testing.T) {
	srv, _, _ := newTestServer(t)
	ts := httptest.NewServer(srv.Handler())
	defer ts.Close()

	big := bytes.Repeat([]byte("a"), maxBodyBytes+1)
	sig := SignGitea(big, testGiteaSecret)
	req, _ := http.NewRequest(http.MethodPost, ts.URL+"/hooks/gitea", bytes.NewReader(big))
	req.Header.Set(giteaSignatureHeader, sig)
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusRequestEntityTooLarge {
		t.Errorf("oversized body = %d, want 413", resp.StatusCode)
	}
}

func TestNewServerRequiresASecret(t *testing.T) {
	cfg := config.EventsConfig{Listen: ":0", StateDir: t.TempDir()}
	if _, err := NewServer(cfg, nil, io.Discard); err == nil ||
		!strings.Contains(err.Error(), "no webhook secrets configured") {
		t.Errorf("NewServer without secrets err = %v, want no-webhook-secrets error", err)
	}
}

func TestServerLogLineLeaksNothing(t *testing.T) {
	var buf bytes.Buffer
	cfg := config.EventsConfig{
		Listen:   ":0",
		StateDir: t.TempDir(),
		Gitea:    config.EventSourceConfig{SecretRef: "literal:" + testGiteaSecret},
	}
	srv, err := NewServer(cfg, nil, &buf)
	if err != nil {
		t.Fatal(err)
	}
	defer srv.Close()
	ts := httptest.NewServer(srv.Handler())
	defer ts.Close()

	// A signed delivery and an unsigned probe both log; neither line may
	// contain the secret or any header VALUE.
	body := `{"action":"approved","number":1,"pull_request":{"number":1}}`
	post(t, ts.URL+"/hooks/gitea", map[string]string{
		giteaSignatureHeader: SignGitea([]byte(body), testGiteaSecret),
		giteaDeliveryHeader:  "leak-check",
	}, body)
	post(t, ts.URL+"/hooks/gitea", nil, body)

	out := buf.String()
	if strings.Contains(out, testGiteaSecret) {
		t.Errorf("log leaks secret:\n%s", out)
	}
	if strings.Contains(out, "payload") {
		t.Errorf("log echoes payload:\n%s", out)
	}
	for _, want := range []string{"kind=pr_approved", "provider_id=leak-check", "rejected source=gitea"} {
		if !strings.Contains(out, want) {
			t.Errorf("log line missing %q:\n%s", want, out)
		}
	}
	// The stored JSONL record must not carry the secret either.
	data, _ := os.ReadFile(srv.store.Path())
	if strings.Contains(string(data), testGiteaSecret) {
		t.Errorf("event log leaks secret: %s", data)
	}
	var ev Event
	if err := json.Unmarshal(data, &ev); err != nil {
		t.Errorf("log line is not valid Event JSON: %v (%s)", err, data)
	}
}