// Package test contains the process-boundary tests of talk 2.0 — the primary
// test seam according to the spec: talkd and talk run as real processes
// (built from this repo), driven via HTTP and the CLI, with two injected
// fakes: an ElevenLabs fake endpoint (httptest server with audio bytes)
// and audio.sink=null. Only externally observable behaviour is tested:
// HTTP responses, CLI exit codes/output, fake hits (order and timing),
// files in the config dir. Tests NEVER bind the default port 7800 and never
// depend on a real daemon — talkd gets a free port via TALK_PORT, CLI
// processes the same one (or port 1 for "daemon dead").
package test

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net"
	"net/http"
	"net/http/httptest"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"
)

// The binaries are built once per test run (the build cache makes it cheap)
// and shared by all tests.
var talkBin string

func TestMain(m *testing.M) {
	dir, err := os.MkdirTemp("", "talk-bins-*")
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
	repo, err := filepath.Abs("..")
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
	build := exec.Command("go", "build", "-o", filepath.Join(dir, "talk"), "./cmd/talk")
	build.Dir = repo
	if out, err := build.CombinedOutput(); err != nil {
		fmt.Fprintf(os.Stderr, "go build ./cmd/talk: %v\n%s", err, out)
		os.RemoveAll(dir)
		os.Exit(1)
	}
	talkBin = filepath.Join(dir, "talk")

	code := m.Run()
	os.RemoveAll(dir)
	os.Exit(code)
}

// syncBuffer is a concurrency-safe buffer (daemon stderr is read while the
// process is running).
type syncBuffer struct {
	mu  sync.Mutex
	buf bytes.Buffer
}

func (b *syncBuffer) Write(p []byte) (int, error) {
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.buf.Write(p)
}

func (b *syncBuffer) String() string {
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.buf.String()
}

// fakeHit is an observed synthesis request at the fake provider.
type fakeHit struct {
	Text      string    // text from the request body
	Start     time.Time // arrival at the fake
	End       time.Time // response sent or cancellation seen
	Completed bool      // true: response written; false: client cancelled
}

// fakeProvider is an ElevenLabs fake (POST /v1/text-to-speech/<voice>): it
// answers with a few bytes of "audio" and logs every request with arrival
// and response time — from which order (text sequence) and serialization
// (arrival of the next after the response of the previous) can be read.
// delay can be switched at runtime to simulate blocking syntheses
// (serialization, priority, cancel). Arrivals are logged separately and
// immediately: they show that the daemon is BUSY with a synthesis (queue
// can be filled deterministically) before the (delayed) response lands as
// a hit.
type fakeProvider struct {
	srv     *httptest.Server
	mu      sync.Mutex
	hits    []fakeHit
	arrived []string
	delay   time.Duration
}

func newFakeProvider(t *testing.T, delay time.Duration) *fakeProvider {
	t.Helper()
	f := &fakeProvider{delay: delay}
	f.srv = httptest.NewServer(http.HandlerFunc(f.serve))
	t.Cleanup(f.srv.Close)
	return f
}

func (f *fakeProvider) serve(w http.ResponseWriter, r *http.Request) {
	var body struct {
		Text string `json:"text"`
	}
	start := time.Now()
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	f.mu.Lock()
	f.arrived = append(f.arrived, body.Text)
	d := f.delay
	f.mu.Unlock()
	if d > 0 {
		select {
		case <-time.After(d):
		case <-r.Context().Done(): // client (daemon) cancelled
			f.record(fakeHit{Text: body.Text, Start: start, End: time.Now()})
			return
		}
	}
	_, _ = w.Write([]byte("\xff\xfb\x90\x00 fake-mp3-bytes"))
	f.record(fakeHit{Text: body.Text, Start: start, End: time.Now(), Completed: true})
}

func (f *fakeProvider) record(h fakeHit) {
	f.mu.Lock()
	defer f.mu.Unlock()
	f.hits = append(f.hits, h)
}

func (f *fakeProvider) setDelay(d time.Duration) {
	f.mu.Lock()
	f.delay = d
	f.mu.Unlock()
}

func (f *fakeProvider) snapshot() []fakeHit {
	f.mu.Lock()
	defer f.mu.Unlock()
	out := make([]fakeHit, len(f.hits))
	copy(out, f.hits)
	return out
}

// completed returns only the completed (not cancelled) hits.
func completed(hits []fakeHit) []fakeHit {
	var out []fakeHit
	for _, h := range hits {
		if h.Completed {
			out = append(out, h)
		}
	}
	return out
}

// waitArrived polls until n synthesis requests have arrived — the daemon is
// then demonstrably busy and the queue can be filled deterministically.
func (f *fakeProvider) waitArrived(t *testing.T, n int) {
	t.Helper()
	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		f.mu.Lock()
		count := len(f.arrived)
		f.mu.Unlock()
		if count >= n {
			return
		}
		time.Sleep(10 * time.Millisecond)
	}
	t.Fatalf("only %d of %d arrivals at the fake within 5 s", len(f.snapshot()), n)
}

// arrivedCount counts the synthesis requests that arrived (including
// cancelled ones) — observation point for "exactly N play, the rest
// parks/expires".
func (f *fakeProvider) arrivedCount() int {
	f.mu.Lock()
	defer f.mu.Unlock()
	return len(f.arrived)
}

// assertNoFurtherArrivals checks that no further synthesis request arrives
// within the deadline (parked/discarded announcements stay silent).
func (f *fakeProvider) assertNoFurtherArrivals(t *testing.T, wait time.Duration) {
	t.Helper()
	n := f.arrivedCount()
	time.Sleep(wait)
	if got := f.arrivedCount(); got != n {
		t.Fatalf("%d additional arrivals (want none) — hits: %+v", got-n, f.snapshot())
	}
}

// waitHits polls until n requests have finished (cancellations count).
func (f *fakeProvider) waitHits(t *testing.T, n int) []fakeHit {
	t.Helper()
	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		if hits := f.snapshot(); len(hits) >= n {
			return hits
		}
		time.Sleep(20 * time.Millisecond)
	}
	t.Fatalf("only %d of %d fake hits within 5 s (hits: %+v)", len(f.snapshot()), n, f.snapshot())
	return nil
}

// waitCompleted polls until n requests have finished SUCCESSFULLY
// (cancelled syntheses do not count).
func (f *fakeProvider) waitCompleted(t *testing.T, n int) []fakeHit {
	t.Helper()
	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		if hits := completed(f.snapshot()); len(hits) >= n {
			return hits
		}
		time.Sleep(20 * time.Millisecond)
	}
	t.Fatalf("only %d of %d completed hits within 5 s (all: %+v)", len(completed(f.snapshot())), n, f.snapshot())
	return nil
}

// assertNoHits checks that no request arrived within the deadline.
func (f *fakeProvider) assertNoHits(t *testing.T, wait time.Duration) {
	t.Helper()
	time.Sleep(wait)
	if hits := f.snapshot(); len(hits) > 0 {
		t.Fatalf("unexpected fake hits: %+v", hits)
	}
}

// daemonProc is a running talkd process.
type daemonProc struct {
	cmd     *exec.Cmd
	port    int
	stderr  *syncBuffer
	baseURL string
}

// startDaemon starts `talk daemon run` as a real process (free port via
// TALK_PORT, never the default port) and waits until GET /status answers.
// Stopped via t.Cleanup: SIGINT, kill after a deadline.
func startDaemon(t *testing.T, root, fakeURL string, extra map[string]string) *daemonProc {
	t.Helper()
	port := freePort(t)
	env := daemonEnv(root, port, fakeURL, extra)
	stderr := &syncBuffer{}
	cmd := exec.Command(talkBin, "daemon", "run")
	cmd.Env = env
	cmd.Stderr = stderr
	if err := cmd.Start(); err != nil {
		t.Fatalf("starting talk daemon run: %v", err)
	}
	d := &daemonProc{
		cmd:     cmd,
		port:    port,
		stderr:  stderr,
		baseURL: fmt.Sprintf("http://127.0.0.1:%d", port),
	}

	client := &http.Client{Timeout: time.Second}
	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		resp, err := client.Get(d.baseURL + "/status")
		if err == nil {
			resp.Body.Close()
			if resp.StatusCode == http.StatusOK {
				t.Cleanup(func() { d.stop(t) })
				return d
			}
		}
		time.Sleep(25 * time.Millisecond)
	}
	t.Fatalf("talk daemon does not answer on %s — stderr:\n%s", d.baseURL+"/status", stderr.String())
	return nil
}

// stop shuts the daemon process down (SIGINT like a human stop; kill
// fallback after 3 s) and waits for it to end.
func (d *daemonProc) stop(t *testing.T) {
	t.Helper()
	if d.cmd.Process == nil {
		return
	}
	done := make(chan error, 1)
	go func() { done <- d.cmd.Wait() }()
	_ = d.cmd.Process.Signal(os.Interrupt)
	select {
	case <-done:
	case <-time.After(3 * time.Second):
		_ = d.cmd.Process.Kill()
		<-done
	}
}

// daemonEnv builds the process environment for talk processes (CLI and
// daemon): the inherited environment without foreign TALK_* variables
// (isolation from keys/ports of the outside world), isolated HOME/
// XDG_CONFIG_HOME (the config dir is thus <root>/talk), audio.sink=null and
// the fake provider as ElevenLabs endpoint. port=1 means "guaranteed dead
// daemon" (connection is refused immediately).
//
// TALK_RATE_LIMIT=0s is the base default of the process-boundary tests: the
// Task-04 semantics tests (serialization, priority, …) enqueue in quick
// succession and expect immediate playback — the law (default 30 s) would
// park them. The law tests in ratelimit_test.go deliberately override the
// value via extra.
func daemonEnv(root string, port int, fakeURL string, extra map[string]string) []string {
	env := make([]string, 0, 32)
	for _, kv := range os.Environ() {
		if strings.HasPrefix(kv, "TALK_") {
			continue
		}
		env = append(env, kv)
	}
	set := map[string]string{
		"HOME":                     root,
		"XDG_CONFIG_HOME":          root,
		"TALK_AUDIO_SINK":          "null",
		"TALK_ELEVENLABS_KEY":      "process-test-key",
		"TALK_ELEVENLABS_ENDPOINT": fakeURL,
		"TALK_EDGE_ENDPOINT":       "ws://127.0.0.1:1/", // the chain must never fall back to real third-party endpoints
		"TALK_PORT":                strconv.Itoa(port),
		"TALK_RATE_LIMIT":          "0s",                                   // law off until a test turns it on (see above)
		"TALK_AUTOSTART":           "false",                                // no test may leave a daemon behind unnoticed; autostart_test.go turns it on deliberately
		"TALK_NOTIFY":              "false",                                // no desktop notifications on the developer's machine; notify_dbus_test.go turns it on against a private bus
		"DBUS_SESSION_BUS_ADDRESS": "unix:path=/nonexistent/talk-test-bus", // never the developer's real session bus (toast tests observe notify-send)
	}
	for k, v := range extra {
		set[k] = v
	}
	for k, v := range set {
		env = append(env, k+"="+v)
	}
	return env
}

// freePort obtains a free loopback port (bind-and-close; the daemon rebinds
// it right afterwards).
func freePort(t *testing.T) int {
	t.Helper()
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("finding a free port: %v", err)
	}
	defer ln.Close()
	return ln.Addr().(*net.TCPAddr).Port
}

// configDir is the config directory under the isolated root (Linux path
// logic: XDG_CONFIG_HOME/<root> → <root>/talk).
func configDir(root string) string {
	return filepath.Join(root, "talk")
}

// talkResult is the observed result of a talk process.
type talkResult struct {
	code   int
	stdout string
	stderr string
}

// runTalk runs the talk CLI as a real process.
func runTalk(t *testing.T, env []string, args ...string) talkResult {
	t.Helper()
	cmd := exec.Command(talkBin, args...)
	cmd.Env = env
	var out, errBuf syncBuffer
	cmd.Stdout = &out
	cmd.Stderr = &errBuf
	err := cmd.Run()
	code := 0
	if ee, ok := err.(*exec.ExitError); ok {
		code = ee.ExitCode()
	} else if err != nil {
		t.Fatalf("running talk: %v (stderr: %s)", err, errBuf.String())
	}
	return talkResult{code: code, stdout: out.String(), stderr: errBuf.String()}
}

// statusBody is the decoded GET /status response.
type statusBody struct {
	Version  string   `json:"version"`
	Queue    int      `json:"queue"`
	QueueIDs []string `json:"queue_ids"`
	Current  *struct {
		ID       string `json:"id"`
		Text     string `json:"text"`
		Priority string `json:"priority"`
	} `json:"current"`
	Muted    bool     `json:"muted"`
	Provider string   `json:"provider"`
	MCP      bool     `json:"mcp"`
	Cors     []string `json:"cors"`
}

// getStatus calls GET /status (deadline: one second — the daemon is local
// and must answer, otherwise that is a test result in itself).
func getStatus(t *testing.T, d *daemonProc) statusBody {
	t.Helper()
	client := &http.Client{Timeout: time.Second}
	resp, err := client.Get(d.baseURL + "/status")
	if err != nil {
		t.Fatalf("GET /status: %v — stderr:\n%s", err, d.stderr.String())
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("GET /status: status %d", resp.StatusCode)
	}
	var st statusBody
	if err := json.NewDecoder(resp.Body).Decode(&st); err != nil {
		t.Fatalf("decoding GET /status: %v", err)
	}
	return st
}

// waitStatusIdle polls until neither an item is running nor waiting.
func waitStatusIdle(t *testing.T, d *daemonProc, timeout time.Duration) {
	t.Helper()
	deadline := time.Now().Add(timeout)
	for {
		st := getStatus(t, d)
		if st.Current == nil && st.Queue == 0 {
			return
		}
		if time.Now().After(deadline) {
			t.Fatalf("queue does not become idle: %+v — stderr:\n%s", st, d.stderr.String())
		}
		time.Sleep(25 * time.Millisecond)
	}
}

// speak enqueues via raw HTTP (process boundary without the CLI).
func speak(t *testing.T, d *daemonProc, body string) (int, map[string]any) {
	t.Helper()
	resp, err := http.Post(d.baseURL+"/speak", "application/json", strings.NewReader(body))
	if err != nil {
		t.Fatalf("POST /speak: %v", err)
	}
	defer resp.Body.Close()
	var m map[string]any
	if err := json.NewDecoder(resp.Body).Decode(&m); err != nil {
		t.Fatalf("decoding POST /speak response: %v", err)
	}
	return resp.StatusCode, m
}

// postPath makes an empty POST to a daemon endpoint (/mute, /unmute,
// /cancel) and decodes the JSON response.
func postPath(t *testing.T, d *daemonProc, path string) (int, map[string]any) {
	t.Helper()
	resp, err := http.Post(d.baseURL+path, "application/json", strings.NewReader("{}"))
	if err != nil {
		t.Fatalf("POST %s: %v", path, err)
	}
	defer resp.Body.Close()
	var m map[string]any
	if err := json.NewDecoder(resp.Body).Decode(&m); err != nil {
		t.Fatalf("decoding POST %s response: %v", path, err)
	}
	return resp.StatusCode, m
}

// rawResponse is a fully read HTTP response (status, header, body as a
// string) — the observation form of the raw CORS/MCP tests.
type rawResponse struct {
	status int
	header http.Header
	body   string
}

// doRequest makes a raw HTTP request with arbitrary headers and an optional
// body and reads the response completely (CORS preflights and MCP JSON-RPC
// payloads are literal, no client SDK in between).
func doRequest(t *testing.T, method, url string, headers map[string]string, body string) rawResponse {
	t.Helper()
	var rd io.Reader
	if body != "" {
		rd = strings.NewReader(body)
	}
	req, err := http.NewRequest(method, url, rd)
	if err != nil {
		t.Fatalf("building %s %s: %v", method, url, err)
	}
	for k, v := range headers {
		req.Header.Set(k, v)
	}
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		t.Fatalf("%s %s: %v", method, url, err)
	}
	defer resp.Body.Close()
	raw, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Fatalf("reading %s %s response: %v", method, url, err)
	}
	return rawResponse{status: resp.StatusCode, header: resp.Header, body: string(raw)}
}

// preflight makes an OPTIONS preflight against /speak (the way a browser
// does before a real POST).
func preflight(t *testing.T, d *daemonProc, origin string) rawResponse {
	t.Helper()
	return doRequest(t, http.MethodOptions, d.baseURL+"/speak", map[string]string{
		"Origin":                        origin,
		"Access-Control-Request-Method": http.MethodPost,
	}, "")
}

// mcpPost POSTs a literal JSON-RPC payload to /mcp.
func mcpPost(t *testing.T, d *daemonProc, payload string) rawResponse {
	t.Helper()
	return doRequest(t, http.MethodPost, d.baseURL+"/mcp", map[string]string{
		"Content-Type": "application/json",
	}, payload)
}

// mcpDecode decodes a JSON-RPC response into a generic map (for field
// access in the literal payload tests).
func mcpDecode(t *testing.T, raw rawResponse) map[string]any {
	t.Helper()
	var m map[string]any
	if err := json.Unmarshal([]byte(raw.body), &m); err != nil {
		t.Fatalf("decoding JSON-RPC response: %v — body: %s", err, raw.body)
	}
	return m
}