package app

import (
	"bytes"
	"context"
	"encoding/json"
	"io"
	"sync"
	"testing"
	"time"

	"github.com/hjbdev/patterm/internal/protocol"
)

func TestNetClientFrameLoopSendsFocusedInput(t *testing.T) {
	clientT, daemonT := protocol.NewLoopbackPair()
	inR, inW := ioPipe(t)
	out := &lockedBuffer{}

	gotInput := make(chan protocol.Input, 1)
	errCh := make(chan error, 1)
	go func() {
		f, err := daemonT.Recv()
		if err != nil {
			errCh <- err
			return
		}
		if f.Type != protocol.FrameAttach {
			t.Errorf("first frame = %s, want attach", f.Type)
			errCh <- nil
			return
		}
		sendTestFrame(t, daemonT, protocol.FrameHello, protocol.Hello{Version: 1, ClientID: "test", ProjectKey: "project"})
		sendTestFrame(t, daemonT, protocol.FrameProjectList, protocol.ProjectList{})
		model := chromeModel{
			ProjectKey: "project",
			FocusedID:  "p1",
			Processes:  []childModel{{ID: "p1", Name: "shell", Kind: string(KindCommand), Status: string(StatusRunning)}},
			Sidebar:    []navEntryModel{{ChildID: "p1"}},
		}
		sendTestFrame(t, daemonT, protocol.FrameChrome, protocol.Chrome{ProjectKey: "project", Model: mustMarshalTest(t, model)})
		sendTestFrame(t, daemonT, protocol.FramePaneSnapshot, protocol.PaneSnapshot{PaneID: "p1", Bytes: []byte("READY")})
		for {
			f, err := daemonT.Recv()
			if err != nil {
				errCh <- err
				return
			}
			if f.Type != protocol.FrameInput {
				continue
			}
			input, err := protocol.Decode[protocol.Input](f)
			if err != nil {
				errCh <- err
				return
			}
			gotInput <- input
			_ = daemonT.Close()
			errCh <- nil
			return
		}
	}()

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	runCh := make(chan error, 1)
	go func() {
		runCh <- RunAttachedClient(ctx, ClientOptions{
			Transport: clientT,
			Stdin:     inR,
			Stdout:    out,
			Cols:      80,
			Rows:      24,
		})
	}()

	deadline := time.Now().Add(3 * time.Second)
	for time.Now().Before(deadline) && !bytes.Contains(out.Bytes(), []byte("READY")) {
		time.Sleep(10 * time.Millisecond)
	}
	if !bytes.Contains(out.Bytes(), []byte("READY")) {
		t.Fatalf("snapshot was not rendered before input; output=%q", out.String())
	}
	if _, err := inW.Write([]byte("echo hi\r")); err != nil {
		t.Fatalf("write stdin: %v", err)
	}
	select {
	case input := <-gotInput:
		if input.PaneID != "p1" || string(input.Bytes) != "echo hi\r" {
			t.Fatalf("input = %#v", input)
		}
	case <-time.After(3 * time.Second):
		t.Fatalf("client did not forward input")
	}
	cancel()
	_ = inW.Close()
	select {
	case err := <-runCh:
		if err != nil {
			t.Fatalf("client run: %v", err)
		}
	case <-time.After(3 * time.Second):
		t.Fatalf("client did not stop")
	}
	if err := <-errCh; err != nil && err != protocol.ErrTransportClosed {
		t.Fatalf("daemon side: %v", err)
	}
}

type lockedBuffer struct {
	mu sync.Mutex
	b  bytes.Buffer
}

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

func (b *lockedBuffer) Bytes() []byte {
	b.mu.Lock()
	defer b.mu.Unlock()
	return append([]byte(nil), b.b.Bytes()...)
}

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

func ioPipe(t *testing.T) (*io.PipeReader, *io.PipeWriter) {
	t.Helper()
	r, w := io.Pipe()
	return r, w
}

func sendTestFrame[T any](t *testing.T, tr protocol.Transport, typ protocol.FrameType, payload T) {
	t.Helper()
	f, err := protocol.NewFrame(typ, payload)
	if err != nil {
		t.Fatalf("frame %s: %v", typ, err)
	}
	if err := tr.Send(f); err != nil {
		t.Fatalf("send %s: %v", typ, err)
	}
}

func mustMarshalTest(t *testing.T, v any) []byte {
	t.Helper()
	b, err := json.Marshal(v)
	if err != nil {
		t.Fatalf("marshal: %v", err)
	}
	return b
}