package grpc

import (
	"context"
	"testing"
	"time"

	agentv1 "github.com/containarr/server/internal/proto/agentv1"
)

func TestRegisterAndGet(t *testing.T) {
	r := NewRegistry()

	state := r.Register("id1", "hostname1", "alias1", "10.0.0.1", "amd64", "linux")
	if state == nil {
		t.Fatal("Register returned nil")
	}

	got, ok := r.Get("id1")
	if !ok {
		t.Fatal("Get returned false for registered agent")
	}
	if got.ID != "id1" || got.Hostname != "hostname1" || got.Alias != "alias1" {
		t.Errorf("unexpected state: %+v", got)
	}
}

func TestGet_NotFound(t *testing.T) {
	r := NewRegistry()
	_, ok := r.Get("nonexistent")
	if ok {
		t.Error("expected false for unknown agent")
	}
}

func TestDeregister(t *testing.T) {
	r := NewRegistry()
	r.Register("id1", "h", "a", "ip", "arch", "os")

	r.Deregister("id1")

	_, ok := r.Get("id1")
	if ok {
		t.Error("agent should not exist after Deregister")
	}
}

func TestDeregister_NotExist(t *testing.T) {
	r := NewRegistry()
	// must not panic
	r.Deregister("ghost")
}

func TestList(t *testing.T) {
	r := NewRegistry()

	if len(r.List()) != 0 {
		t.Error("expected empty list")
	}

	r.Register("a1", "h1", "", "", "", "")
	r.Register("a2", "h2", "", "", "", "")

	if len(r.List()) != 2 {
		t.Errorf("expected 2 agents, got %d", len(r.List()))
	}
}

func TestUpdateContainers(t *testing.T) {
	r := NewRegistry()
	r.Register("id1", "h", "a", "ip", "arch", "os")

	before := time.Now()
	containers := []*agentv1.ContainerInfo{
		{Id: "c1", Name: "web"},
		{Id: "c2", Name: "db"},
	}
	r.UpdateContainers("id1", containers)

	got, _ := r.Get("id1")
	if len(got.Containers) != 2 {
		t.Errorf("expected 2 containers, got %d", len(got.Containers))
	}
	if got.LastSeenAt.Before(before) {
		t.Error("LastSeenAt should have been updated")
	}
}

func TestUpdateContainers_UnknownAgent(t *testing.T) {
	r := NewRegistry()
	// must not panic
	r.UpdateContainers("ghost", nil)
}

func TestUpdateAlias(t *testing.T) {
	r := NewRegistry()
	r.Register("id1", "h", "old-alias", "ip", "arch", "os")

	r.UpdateAlias("id1", "new-alias")

	got, _ := r.Get("id1")
	if got.Alias != "new-alias" {
		t.Errorf("expected 'new-alias', got %q", got.Alias)
	}
}

func TestUpdateAlias_UnknownAgent(t *testing.T) {
	r := NewRegistry()
	// must not panic
	r.UpdateAlias("ghost", "alias")
}

func TestSend(t *testing.T) {
	r := NewRegistry()
	state := r.Register("id1", "h", "a", "ip", "arch", "os")

	msg := &agentv1.ServerMessage{}
	ok := r.Send("id1", msg)
	if !ok {
		t.Fatal("Send returned false for connected agent")
	}

	// Drain the channel to verify the message arrived.
	select {
	case got := <-state.cmdCh:
		if got != msg {
			t.Error("received wrong message")
		}
	case <-time.After(time.Second):
		t.Fatal("timed out reading from cmdCh")
	}
}

func TestSend_UnknownAgent(t *testing.T) {
	r := NewRegistry()
	ok := r.Send("ghost", &agentv1.ServerMessage{})
	if ok {
		t.Error("Send should return false for unknown agent")
	}
}

func TestSend_FullChannel(t *testing.T) {
	r := NewRegistry()
	r.Register("id1", "h", "a", "ip", "arch", "os")

	// Fill the buffer (size 16)
	for i := 0; i < 16; i++ {
		r.Send("id1", &agentv1.ServerMessage{})
	}

	// Next send on a full channel should return false
	ok := r.Send("id1", &agentv1.ServerMessage{})
	if ok {
		t.Error("Send should return false when channel is full")
	}
}

// ── Pending file correlations ──────────────────────────────────────────────────

func TestRegisterPending_UnknownAgent(t *testing.T) {
	r := NewRegistry()
	ch := r.RegisterPending("ghost", "cmd1")
	if ch != nil {
		t.Error("expected nil channel for unknown agent")
	}
}

func TestResolvePending_Success(t *testing.T) {
	r := NewRegistry()
	r.Register("id1", "h", "a", "ip", "arch", "os")

	ch := r.RegisterPending("id1", "cmd1")
	if ch == nil {
		t.Fatal("expected non-nil channel")
	}

	result := &agentv1.FileResult{CommandId: "cmd1", Success: true, Content: []byte("data")}
	r.ResolvePending("id1", "cmd1", result)

	select {
	case got := <-ch:
		if got.CommandId != "cmd1" || !got.Success {
			t.Errorf("unexpected result: %+v", got)
		}
	case <-time.After(time.Second):
		t.Fatal("timed out waiting for resolve")
	}
}

func TestResolvePending_UnknownAgent(t *testing.T) {
	r := NewRegistry()
	// must not panic
	r.ResolvePending("ghost", "cmd1", &agentv1.FileResult{})
}

func TestResolvePending_UnknownCmd(t *testing.T) {
	r := NewRegistry()
	r.Register("id1", "h", "a", "ip", "arch", "os")
	// must not panic
	r.ResolvePending("id1", "nonexistent", &agentv1.FileResult{})
}

func TestCancelPending(t *testing.T) {
	r := NewRegistry()
	r.Register("id1", "h", "a", "ip", "arch", "os")

	r.RegisterPending("id1", "cmd1")
	r.CancelPending("id1", "cmd1")

	// After cancel, resolving should be a no-op (not panic)
	r.ResolvePending("id1", "cmd1", &agentv1.FileResult{})
}

func TestCancelPending_UnknownAgent(t *testing.T) {
	r := NewRegistry()
	// must not panic
	r.CancelPending("ghost", "cmd1")
}

func TestSendAndWaitCtx_AgentNotConnected(t *testing.T) {
	r := NewRegistry()
	ctx := context.Background()
	_, err := r.SendAndWaitCtx(ctx, "ghost", &agentv1.ServerMessage{}, "cmd1")
	if err == nil || err.Error() != "agent not connected" {
		t.Errorf("expected 'agent not connected', got %v", err)
	}
}

func TestSendAndWaitCtx_Timeout(t *testing.T) {
	r := NewRegistry()
	r.Register("id1", "h", "a", "ip", "arch", "os")

	// Use an already-cancelled context to force immediate timeout.
	ctx, cancel := context.WithCancel(context.Background())
	cancel() // cancel immediately

	_, err := r.SendAndWaitCtx(ctx, "id1", &agentv1.ServerMessage{}, "cmd-timeout")
	if err == nil {
		t.Error("expected timeout or not-connected error")
	}
}

func TestSendAndWaitCtx_Success(t *testing.T) {
	r := NewRegistry()
	r.Register("id1", "h", "a", "ip", "arch", "os")

	cmdID := "cmd-success"
	expected := &agentv1.FileResult{CommandId: cmdID, Success: true, Content: []byte("hello")}

	// Simulate the agent responding after the send.
	go func() {
		// Wait briefly for RegisterPending + Send to happen.
		time.Sleep(10 * time.Millisecond)
		r.ResolvePending("id1", cmdID, expected)
	}()

	ctx := context.Background()
	result, err := r.SendAndWaitCtx(ctx, "id1", &agentv1.ServerMessage{}, cmdID)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if result.CommandId != cmdID || !result.Success {
		t.Errorf("unexpected result: %+v", result)
	}
}