package xmppsig

import (
	"context"
	"encoding/xml"
	"strings"
	"sync"
	"testing"
	"time"

	"dev.narayana.im/narayana/telegabber/calls/signaling"
	"dev.narayana.im/narayana/telegabber/xmpp/jingle"

	"github.com/pion/webrtc/v4"
	"gosrc.io/xmpp/stanza"
)

// goroutine-safe; Session.Send fires from background goroutines after
// JMI <proceed>
type recSender struct {
	mu     sync.Mutex
	sent   []stanza.Packet
	iqSent []*stanza.IQ
}

func (r *recSender) Send(p stanza.Packet) error {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.sent = append(r.sent, p)
	if iq, ok := p.(*stanza.IQ); ok {
		r.iqSent = append(r.iqSent, iq)
	}
	return nil
}

func (r *recSender) SendIQ(_ context.Context, iq *stanza.IQ) (chan stanza.IQ, error) {
	ch := make(chan stanza.IQ, 1)
	return ch, r.Send(iq)
}

func (r *recSender) SendRaw(string) error { return nil }

func (r *recSender) snapshot() []stanza.Packet {
	r.mu.Lock()
	defer r.mu.Unlock()
	out := make([]stanza.Packet, len(r.sent))
	copy(out, r.sent)
	return out
}

func (r *recSender) firstMessage() *stanza.Message {
	for _, p := range r.snapshot() {
		switch m := p.(type) {
		case *stanza.Message:
			return m
		case stanza.Message:
			return &m
		}
	}
	return nil
}

// records bridge-side Terminate firings; serves as the other-side stand-in
// for tests of either xmppsig.Caller or xmppsig.Callee
type recBridgeSide struct {
	mu              sync.Mutex
	startedOrAccept bool
	terminated      bool
	terminateReason signaling.TerminationReason
}

func (r *recBridgeSide) Start()   { r.mu.Lock(); r.startedOrAccept = true; r.mu.Unlock() }
func (r *recBridgeSide) Ringing() {}
func (r *recBridgeSide) Accept()  { r.mu.Lock(); r.startedOrAccept = true; r.mu.Unlock() }
func (r *recBridgeSide) Terminate(reason signaling.TerminationReason) {
	r.mu.Lock()
	r.terminated = true
	r.terminateReason = reason
	r.mu.Unlock()
}
func (r *recBridgeSide) isTerminated() bool {
	r.mu.Lock()
	defer r.mu.Unlock()
	return r.terminated
}
func (r *recBridgeSide) reason() signaling.TerminationReason {
	r.mu.Lock()
	defer r.mu.Unlock()
	return r.terminateReason
}

type noopTimers struct{}

func (noopTimers) Set(signaling.TimerKind, time.Duration) {}
func (noopTimers) Cancel(signaling.TimerKind)             {}

// real pion PC; faking webrtc is more invasive than running on loopback
func pcFactory(t *testing.T) func() (*webrtc.PeerConnection, error) {
	t.Helper()
	return func() (*webrtc.PeerConnection, error) {
		pc, err := webrtc.NewPeerConnection(webrtc.Configuration{})
		if err != nil {
			return nil, err
		}
		t.Cleanup(func() { _ = pc.Close() })
		if _, err := pc.AddTransceiverFromKind(webrtc.RTPCodecTypeAudio, webrtc.RTPTransceiverInit{
			Direction: webrtc.RTPTransceiverDirectionSendrecv,
		}); err != nil {
			_ = pc.Close()
			return nil, err
		}
		return pc, nil
	}
}

// OnTerminated fires bridge.Terminate on a goroutine (deferred re-entry),
// so callers poll
func waitUntil(t *testing.T, desc string, d time.Duration, cond func() bool) {
	t.Helper()
	deadline := time.Now().Add(d)
	for time.Now().Before(deadline) {
		if cond() {
			return
		}
		time.Sleep(10 * time.Millisecond)
	}
	t.Fatalf("waitUntil(%s): timed out after %v", desc, d)
}

// JMI <propose> must use a full JID (userID@gw/telegabber). XEP-0353
// requires it so the recipient can route <proceed>/<reject> back.

func TestCallerStart_SendsProposeWithFullLocalJID(t *testing.T) {
	send := &recSender{}
	mgr := &jingle.Manager{LocalJID: "gw.example", Sender: send}
	a := NewAdapter(AdapterConfig{
		Sender: send, LocalJID: "gw.example", Manager: mgr,
		PCFactory: pcFactory(t),
	})
	caller, err := a.NewCaller("alice@xmpp.example", 12345)
	if err != nil {
		t.Fatalf("NewCaller: %v", err)
	}
	br := signaling.New(signaling.Config{
		Caller: caller, Callee: &recBridgeSide{}, Timers: noopTimers{},
	})
	caller.Bind(br)

	br.Start() // triggers caller.Start synchronously

	msg := send.firstMessage()
	if msg == nil {
		t.Fatal("no message sent - Caller.Start did not produce a JMI <propose>")
	}
	if msg.From != "12345@gw.example/telegabber" {
		t.Errorf("propose from = %q, want %q (full JID with resource per XEP-0353)", msg.From, "12345@gw.example/telegabber")
	}
	if msg.To != "alice@xmpp.example" {
		t.Errorf("propose to = %q, want alice@xmpp.example", msg.To)
	}
	if string(msg.Type) != "chat" {
		t.Errorf("propose type = %q, want chat", msg.Type)
	}

	// payload: one <propose> in JMI ns with a <description media="audio">
	xmlBytes, err := xml.Marshal(msg)
	if err != nil {
		t.Fatalf("marshal: %v", err)
	}
	s := string(xmlBytes)
	if !strings.Contains(s, `<propose xmlns="urn:xmpp:jingle-message:0"`) {
		t.Errorf("propose missing JMI namespace: %s", s)
	}
	if !strings.Contains(s, `<description xmlns="urn:xmpp:jingle:apps:rtp:1" media="audio"`) {
		t.Errorf("propose missing rtp description with media=audio: %s", s)
	}
}

// cross-side teardown for TG-originated calls:
// inbound <reject>/<retract>/session-terminate -> observer -> bridge.Terminate

func TestCallerOnTerminated_RejectedReason_TearsDownTGCalleeWithDecline(t *testing.T) {
	caller, tgSide := newStartedCaller(t)
	caller.OnTerminated("rejected")

	waitUntil(t, "tg-Callee.Terminate", time.Second, tgSide.isTerminated)
	if tgSide.reason() != signaling.ReasonDecline {
		t.Errorf("tg-side reason = %v, want ReasonDecline", tgSide.reason())
	}
}

// Caller bound to a TG-originated bridge, started so the session is in
// StateProposed; returns the Caller and the tg-side stand-in
func newStartedCaller(t *testing.T) (*Caller, *recBridgeSide) {
	t.Helper()
	send := &recSender{}
	mgr := &jingle.Manager{LocalJID: "gw.example", Sender: send}
	a := NewAdapter(AdapterConfig{
		Sender: send, LocalJID: "gw.example", Manager: mgr,
		PCFactory: pcFactory(t),
	})
	caller, err := a.NewCaller("alice@xmpp.example", 12345)
	if err != nil {
		t.Fatalf("NewCaller: %v", err)
	}
	tgSide := &recBridgeSide{}
	br := signaling.New(signaling.Config{
		Caller: caller, Callee: tgSide, Timers: noopTimers{},
	})
	caller.Bind(br)
	br.Start()
	waitUntil(t, "session proposed", time.Second, func() bool {
		s := caller.sessionRef()
		return s != nil && s.State() == jingle.StateProposed
	})
	return caller, tgSide
}