package service

import (
	"testing"
	"time"
)

// V2.2.1 ②: the ⚡ probe for an agent-managed node is synthesized
// from the agent's heartbeat stamp instead of dialing the placeholder
// address. These tests pin the pure verdict: fresh stamp → online
// with the heartbeat age as latency; stale / never-seen → offline
// with LatencyMs -1; LastError empty in every case (a dial error must
// never be recorded for an agent node again).

func TestAgentHeartbeatVerdictFreshIsOnlineWithAgeLatency(t *testing.T) {
	now := time.Unix(1_700_000_000, 0)
	lastSeenMs := now.Add(-30 * time.Second).UnixMilli()
	patch, online := agentHeartbeatVerdict(lastSeenMs, now)
	if !online {
		t.Fatal("30s-old heartbeat must read online")
	}
	if patch.LatencyMs != 30_000 {
		t.Fatalf("LatencyMs = %d, want heartbeat age 30000", patch.LatencyMs)
	}
	if patch.LastHeartbeat != now.Unix() {
		t.Fatalf("LastHeartbeat = %d, want now %d", patch.LastHeartbeat, now.Unix())
	}
	if patch.LastError != "" {
		t.Fatalf("LastError = %q, want empty", patch.LastError)
	}
}

func TestAgentHeartbeatVerdictWindowEdge(t *testing.T) {
	now := time.Unix(1_700_000_000, 0)
	if _, online := agentHeartbeatVerdict(now.Add(-agentOnlineWindow).UnixMilli(), now); !online {
		t.Fatal("heartbeat exactly at the window edge must read online")
	}
	if _, online := agentHeartbeatVerdict(now.Add(-agentOnlineWindow-time.Second).UnixMilli(), now); online {
		t.Fatal("heartbeat past the window must read offline")
	}
}

func TestAgentHeartbeatVerdictStaleIsOffline(t *testing.T) {
	now := time.Unix(1_700_000_000, 0)
	lastSeenMs := now.Add(-10 * time.Minute).UnixMilli()
	patch, online := agentHeartbeatVerdict(lastSeenMs, now)
	if online {
		t.Fatal("10min-old heartbeat must read offline")
	}
	if patch.LatencyMs != -1 {
		t.Fatalf("LatencyMs = %d, want -1", patch.LatencyMs)
	}
	if patch.LastHeartbeat != lastSeenMs/1000 {
		t.Fatalf("LastHeartbeat = %d, want the truthful last-seen %d", patch.LastHeartbeat, lastSeenMs/1000)
	}
	if patch.LastError != "" {
		t.Fatalf("LastError = %q, want empty", patch.LastError)
	}
}

func TestAgentHeartbeatVerdictNeverSeenIsOffline(t *testing.T) {
	now := time.Unix(1_700_000_000, 0)
	patch, online := agentHeartbeatVerdict(0, now)
	if online {
		t.Fatal("never-seen agent must read offline")
	}
	if patch.LatencyMs != -1 || patch.LastHeartbeat != 0 || patch.LastError != "" {
		t.Fatalf("patch = %+v, want zero stamp, latency -1, no error", patch)
	}
}