package monitor

import (
	"io"
	"log"
	"sync"
	"testing"

	"gitea.dooplex.hu/admin/felhom-hub/internal/store"
)

// R-523 — the checker that turns the agent's controller_supervisor stanza into events.
// The JSON below is the exact wire shape the agent's TestControllerSupervisorStanza_WireShape pins.

func supReport(guests string) []byte {
	return []byte(`{"host_id":"h1","controller_supervisor":{"guests":` + guests + `}}`)
}

type evRec struct {
	mu  sync.Mutex
	evs []string
}

func (r *evRec) fn(_, et, sev, _, _, _ string) {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.evs = append(r.evs, et+"/"+sev)
}
func (r *evRec) take() []string {
	r.mu.Lock()
	defer r.mu.Unlock()
	out := r.evs
	r.evs = nil
	return out
}

// The consequence: an agent restart of a controller reaches the dispatcher as
// controller_restarted_by_agent, once; a crash-loop reaches it as controller_crashloop (error).
//
// RED-PROOF: make observe() skip the `LastRestartAt != prev.lastRestartAt` branch → the second
// Check emits nothing → "restart did not produce controller_restarted_by_agent".
func TestControllerSupervisorChecker_EmitsOnMovement(t *testing.T) {
	st := newCapStore(t)
	rec := &evRec{}
	c := NewControllerSupervisorChecker(st, rec.fn, log.New(io.Discard, "", 0))

	// Seed: an old restart already recorded at first sight → silent.
	st.SaveHostReport("h1", "c1", supReport(`[{"vmid":9201,"restarts_total":1,"last_restart_at":"2026-09-15T08:00:00Z","last_reason":"exited","crashloop":false,"parked":false}]`), store.HostReportDenorm{})
	c.Check()
	if evs := rec.take(); len(evs) != 0 {
		t.Fatalf("first observation must seed silently, got %v", evs)
	}
	// Same record again → silent.
	c.Check()
	if evs := rec.take(); len(evs) != 0 {
		t.Fatalf("unchanged record emitted %v", evs)
	}
	// A new restart.
	st.SaveHostReport("h1", "c1", supReport(`[{"vmid":9201,"restarts_total":2,"last_restart_at":"2026-09-15T09:00:00Z","last_reason":"exited","crashloop":false,"parked":false}]`), store.HostReportDenorm{})
	c.Check()
	if evs := rec.take(); len(evs) != 1 || evs[0] != "controller_restarted_by_agent/info" {
		t.Fatalf("restart did not produce controller_restarted_by_agent (got %v)", evs)
	}
	// Agent restarted (counter back to 1) with a NEW timestamp → still an event.
	st.SaveHostReport("h1", "c1", supReport(`[{"vmid":9201,"restarts_total":1,"last_restart_at":"2026-09-15T10:00:00Z","last_reason":"absent","crashloop":false,"parked":false}]`), store.HostReportDenorm{})
	c.Check()
	if evs := rec.take(); len(evs) != 1 || evs[0] != "controller_restarted_by_agent/info" {
		t.Fatalf("a restart after an agent restart (counter reset) was lost: %v", evs)
	}
	// Crash-loop.
	st.SaveHostReport("h1", "c1", supReport(`[{"vmid":9201,"restarts_total":4,"last_restart_at":"2026-09-15T10:00:00Z","last_reason":"exited","crashloop":true,"crashloop_since":"2026-09-15T10:05:00Z","parked":false}]`), store.HostReportDenorm{})
	c.Check()
	if evs := rec.take(); len(evs) != 1 || evs[0] != "controller_crashloop/error" {
		t.Fatalf("crash-loop did not produce controller_crashloop/error (got %v)", evs)
	}
	// A pre-v0.131.0 report (no stanza) → nothing.
	st.SaveHostReport("h1", "c1", []byte(`{"host_id":"h1"}`), store.HostReportDenorm{})
	c.Check()
	if evs := rec.take(); len(evs) != 0 {
		t.Fatalf("a report without the stanza emitted %v", evs)
	}
}

// A hub restarted DURING a crash-loop must say so once, not seed it away.
func TestControllerSupervisorChecker_CrashloopAtFirstSightEmits(t *testing.T) {
	st := newCapStore(t)
	rec := &evRec{}
	c := NewControllerSupervisorChecker(st, rec.fn, log.New(io.Discard, "", 0))
	st.SaveHostReport("h1", "c1", supReport(`[{"vmid":9201,"restarts_total":3,"last_restart_at":"2026-09-15T10:00:00Z","crashloop":true,"crashloop_since":"2026-09-15T10:05:00Z"}]`), store.HostReportDenorm{})
	c.Check()
	c.Check()
	if evs := rec.take(); len(evs) != 1 || evs[0] != "controller_crashloop/error" {
		t.Fatalf("crash-loop at first sight: want exactly one controller_crashloop, got %v", evs)
	}
}