package dispatcher

import (
	"errors"
	"testing"
	"time"

	agentpb "git.ipao.vip/rogee/go-sip/gen/agent"
	"git.ipao.vip/rogee/go-sip/internal/session"
	"git.ipao.vip/rogee/go-sip/internal/store"
	"google.golang.org/protobuf/proto"
)

type inboundSessionTestClient struct {
	agentpb.AgentControlServiceClient
}

func TestInboundAgentFactRequiresCurrentUnexpiredActivatedSession(t *testing.T) {
	now := time.Date(2026, 9, 21, 2, 0, 0, 0, time.UTC)
	coordinator := NewAgentCoordinator(func() time.Time { return now })
	if err := coordinator.Register("agent-a", &inboundSessionTestClient{}); err != nil {
		t.Fatal(err)
	}
	coordinator.sessions["agent-a"] = AgentSession{
		AgentID: "agent-a", CellID: "cell-a", BootID: "boot-a", DispatcherEpoch: "epoch-a",
		SessionGeneration: 3, ExpiresAtUnixMs: now.Add(time.Minute).UnixMilli(),
	}
	meta := &agentpb.RequestMeta{
		ProtocolVersion: "agent.v1", AgentId: "agent-a", CellId: "cell-a", BootId: "boot-a",
		DispatcherEpoch: "epoch-a", SessionGeneration: 3,
	}
	if err := coordinator.AuthorizeInboundMeta(meta); err != nil {
		t.Fatalf("active Agent was refused: %v", err)
	}
	for _, tc := range []struct {
		name       string
		change     func(*agentpb.RequestMeta)
		transition bool
	}{
		{"old boot", func(m *agentpb.RequestMeta) { m.BootId = "boot-old" }, false},
		{"old generation", func(m *agentpb.RequestMeta) { m.SessionGeneration = 2 }, true},
		{"next generation before activation response", func(m *agentpb.RequestMeta) { m.SessionGeneration = 4 }, true},
		{"distant generation", func(m *agentpb.RequestMeta) { m.SessionGeneration = 7 }, false},
		{"missing generation", func(m *agentpb.RequestMeta) { m.SessionGeneration = 0 }, false},
		{"other cell", func(m *agentpb.RequestMeta) { m.CellId = "cell-other" }, false},
		{"other epoch", func(m *agentpb.RequestMeta) { m.DispatcherEpoch = "epoch-other" }, false},
		{"unregistered Agent", func(m *agentpb.RequestMeta) { m.AgentId = "agent-other" }, false},
		{"old boot and generation", func(m *agentpb.RequestMeta) { m.BootId = "boot-old"; m.SessionGeneration = 2 }, false},
	} {
		t.Run(tc.name, func(t *testing.T) {
			changed := proto.Clone(meta).(*agentpb.RequestMeta)
			tc.change(changed)
			err := coordinator.AuthorizeInboundMeta(changed)
			if !errors.Is(err, store.ErrCommandConflict) || errors.Is(err, session.ErrGenerationTransition) != tc.transition {
				t.Fatalf("Agent report refusal classification: got %v, transition=%t", err, tc.transition)
			}
		})
	}
	now = now.Add(time.Minute)
	if err := coordinator.AuthorizeInboundMeta(meta); !errors.Is(err, store.ErrCommandConflict) {
		t.Fatalf("expired Agent report passed: %v", err)
	}
	stale := proto.Clone(meta).(*agentpb.RequestMeta)
	stale.SessionGeneration = 2
	if err := coordinator.AuthorizeInboundMeta(stale); errors.Is(err, session.ErrGenerationTransition) {
		t.Fatalf("expired Agent session misclassified as a transient cutover: %v", err)
	}
}