package rpc

import (
	"strings"
	"testing"
	"time"

	agentpb "git.ipao.vip/rogee/go-sip/gen/agent"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

func TestSessionRegistryPersistsGenerationAcrossRestart(t *testing.T) {
	path := t.TempDir() + "/rpc-session.json"
	first := NewSessionRegistry(path)
	_, _, err := first.Activate(&agentpb.AgentBinding{AgentId: "agent-1", CellId: "cell-1", ExpectedBootId: "boot-1", DispatcherEpoch: "epoch-1", SessionGeneration: 3}, "activate-1", "digest-1", time.Unix(100, 0))
	if err != nil {
		t.Fatal(err)
	}
	second := NewSessionRegistry(path)
	_, _, err = second.Activate(&agentpb.AgentBinding{AgentId: "agent-1", CellId: "cell-1", ExpectedBootId: "boot-2", DispatcherEpoch: "epoch-2", SessionGeneration: 2}, "activate-2", "digest-2", time.Unix(100, 0))
	if status.Code(err) != codes.Aborted {
		t.Fatalf("error = %v, want persisted generation fence", err)
	}
	if _, _, err := second.Activate(&agentpb.AgentBinding{AgentId: "agent-1", CellId: "cell-1", ExpectedBootId: "boot-2", DispatcherEpoch: "epoch-2", SessionGeneration: 4}, "activate-3", "digest-3", time.Unix(100, 0)); err != nil {
		t.Fatal(err)
	}
}

func TestSessionRegistryZeroGenerationAdvancesDurableHighwaterAfterRestart(t *testing.T) {
	path := t.TempDir() + "/rpc-session.json"
	first := NewSessionRegistry(path)
	now := time.Unix(100, 0)
	if _, _, err := first.Activate(&agentpb.AgentBinding{AgentId: "agent-1", CellId: "cell-1", ExpectedBootId: "boot-1", DispatcherEpoch: "epoch-1", SessionGeneration: 7}, "activate-1", "digest-1", now); err != nil {
		t.Fatal(err)
	}
	second := NewSessionRegistry(path)
	session, replay, err := second.Activate(&agentpb.AgentBinding{AgentId: "agent-1", CellId: "cell-1", ExpectedBootId: "boot-2", DispatcherEpoch: "epoch-2"}, "activate-2", "digest-2", now)
	if err != nil || replay || session.GetSessionGeneration() != 8 {
		t.Fatalf("Agent could not advance persisted fencing after restart: session=%v replay=%t err=%v", session, replay, err)
	}
	third := NewSessionRegistry(path)
	if _, _, err := third.Activate(&agentpb.AgentBinding{AgentId: "agent-1", CellId: "cell-1", ExpectedBootId: "boot-3", DispatcherEpoch: "epoch-3", SessionGeneration: 7}, "activate-3", "digest-3", now); status.Code(err) != codes.Aborted {
		t.Fatalf("explicit stale generation bypassed the durable fence: %v", err)
	}
}

func TestSessionRegistryZeroGenerationDoesNotWrapAtExhaustion(t *testing.T) {
	path := t.TempDir() + "/rpc-session.json"
	first := NewSessionRegistry(path)
	now := time.Unix(100, 0)
	if _, _, err := first.Activate(&agentpb.AgentBinding{AgentId: "agent-1", CellId: "cell-1", ExpectedBootId: "boot-1", DispatcherEpoch: "epoch-1", SessionGeneration: ^uint64(0)}, "activate-1", "digest-1", now); err != nil {
		t.Fatal(err)
	}
	for _, tc := range []struct {
		name     string
		registry *SessionRegistry
		boot     string
	}{
		{"active", first, "boot-1"},
		{"after restart", NewSessionRegistry(path), "boot-2"},
	} {
		t.Run(tc.name, func(t *testing.T) {
			_, _, err := tc.registry.Activate(&agentpb.AgentBinding{AgentId: "agent-1", CellId: "cell-1", ExpectedBootId: tc.boot, DispatcherEpoch: "epoch-2"}, "activate-2", "digest-2", now)
			if status.Code(err) != codes.Aborted || !strings.Contains(err.Error(), "exhausted") {
				t.Fatalf("exhausted generation wrapped or was hidden: %v", err)
			}
		})
	}
}