package emotion

import "testing"

// newTestObserver builds an observer over one persona whose affection step is 10,
// capturing every emitted update.
func newTestObserver(t *testing.T, id string, decay float64, initial EmotionState) (*Observer, *Machine, *Affection, *[]Update) {
	t.Helper()
	machine, err := NewMachine(Params{InitialState: initial, DecayRate: decay})
	if err != nil {
		t.Fatalf("NewMachine: %v", err)
	}
	affection, err := NewAffection(50, 0, 700)
	if err != nil {
		t.Fatalf("NewAffection: %v", err)
	}
	mgr := NewManager()
	mgr.Set(id, machine, affection)

	emitted := &[]Update{}
	obs := NewObserver(mgr, func(string) int { return 10 }, func(u Update) {
		*emitted = append(*emitted, u)
	})
	return obs, machine, affection, emitted
}

// TestObserveMovesEmotionAndAffection locks the turn rule: a warm turn raises the
// mood toward happy/excited and steps affection up by the persona's configured
// magnitude, a cold turn lowers both, and the change is reported for broadcast.
func TestObserveMovesEmotionAndAffection(t *testing.T) {
	t.Parallel()
	obs, machine, affection, emitted := newTestObserver(t, "cyrene", 0.5, Calm)

	if got := obs.Observe("cyrene", "今天谢谢你呀", true); got != Happy {
		t.Fatalf("warm turn mood = %s, want happy", got)
	}
	if affection.Value() != 60 {
		t.Fatalf("affection after warm turn = %d, want 60 (50+10)", affection.Value())
	}
	if got := obs.Observe("cyrene", "我今天好累，有点难过", true); got != Sad {
		t.Fatalf("down turn mood = %s, want sad", got)
	}
	if affection.Value() != 50 {
		t.Fatalf("affection after down turn = %d, want 50 (60-10)", affection.Value())
	}
	// A cue-free turn carries no signal: the emotion decays toward calm instead of
	// jumping, so sad → calm.
	if got := obs.Observe("cyrene", "帮我看下这个报错", true); got != Calm {
		t.Fatalf("neutral turn mood = %s, want decayed calm", got)
	}
	if len(*emitted) != 3 {
		t.Fatalf("emitted = %d, want 3 (one per real mood change)", len(*emitted))
	}
	if machine.Current() != Calm {
		t.Fatalf("machine current = %s, want calm", machine.Current())
	}
}

// TestObserveEmitsOnlyOnChange locks the noise guard: a turn that leaves the mood
// where it already was emits nothing, while a turn that moves it emits once.
func TestObserveEmitsOnlyOnChange(t *testing.T) {
	t.Parallel()
	obs, _, _, emitted := newTestObserver(t, "cyrene", 0.5, Calm)

	// calm + neutral → calm: no change, no event.
	if got := obs.Observe("cyrene", "把这段代码格式化一下", true); got != Calm {
		t.Fatalf("neutral turn mood = %s, want calm", got)
	}
	if len(*emitted) != 0 {
		t.Fatalf("emitted = %d, want 0 for an unchanged mood", len(*emitted))
	}
	// calm + warm → happy: one event.
	obs.Observe("cyrene", "谢谢你", true)
	// happy + warm → happy: unchanged, no second event.
	obs.Observe("cyrene", "辛苦啦", true)
	if len(*emitted) != 1 {
		t.Fatalf("emitted = %d, want 1 (only the real change)", len(*emitted))
	}
}

// TestObserveDecayDisabledByRate locks the persona's decayRate knob: with decay
// off, a cue-free turn leaves the mood untouched.
func TestObserveDecayDisabledByRate(t *testing.T) {
	t.Parallel()
	obs, machine, _, emitted := newTestObserver(t, "cyrene", 0, Happy)

	if got := obs.Observe("cyrene", "帮我把日志改成 debug", true); got != Happy {
		t.Fatalf("mood with decay disabled = %s, want happy unchanged", got)
	}
	if machine.Current() != Happy {
		t.Fatalf("machine current = %s, want happy", machine.Current())
	}
	if len(*emitted) != 0 {
		t.Fatalf("emitted = %d, want 0", len(*emitted))
	}
}

// TestObserveRestrictedConversationIsReadOnly locks the isolation boundary: a
// group-chat/stranger turn (writable=false) never moves the persona's mood or
// affection, mirroring the read-only memory lane (design/02 §3, design/11 §2).
func TestObserveRestrictedConversationIsReadOnly(t *testing.T) {
	t.Parallel()
	obs, machine, affection, emitted := newTestObserver(t, "cyrene", 0.5, Calm)

	if got := obs.Observe("cyrene", "我很喜欢你", false); got != "" {
		t.Fatalf("restricted turn mood = %q, want empty", got)
	}
	if machine.Current() != Calm || affection.Value() != 50 {
		t.Fatalf("restricted turn changed state to %s/%d, want calm/50", machine.Current(), affection.Value())
	}
	if len(*emitted) != 0 {
		t.Fatalf("emitted = %d, want 0 for a restricted turn", len(*emitted))
	}
}

// TestObserveUnknownPersonaIsNoop locks the persona-scoping guard: an unregistered
// persona id yields no mood and no panic.
func TestObserveUnknownPersonaIsNoop(t *testing.T) {
	t.Parallel()
	obs, machine, _, _ := newTestObserver(t, "cyrene", 0.5, Calm)

	if got := obs.Observe("someone-else", "我爱你", true); got != "" {
		t.Fatalf("unknown persona mood = %q, want empty", got)
	}
	if machine.Current() != Calm {
		t.Fatalf("unknown persona id moved the registered machine to %s", machine.Current())
	}
	if got := obs.Observe("", "我爱你", true); got != "" {
		t.Fatalf("empty persona mood = %q, want empty", got)
	}
}

// TestObserveKeepsPersonasSeparate locks the per-persona isolation the whole
// mechanism rests on (design/01 §2: emotion follows the persona): a turn applied
// to one persona leaves every other persona untouched.
func TestObserveKeepsPersonasSeparate(t *testing.T) {
	t.Parallel()
	aMachine, err := NewMachine(Params{InitialState: Calm, DecayRate: 0.5})
	if err != nil {
		t.Fatalf("NewMachine: %v", err)
	}
	aAffection, err := NewAffection(50, 0, 700)
	if err != nil {
		t.Fatalf("NewAffection: %v", err)
	}
	bMachine, err := NewMachine(Params{InitialState: Calm, DecayRate: 0.5})
	if err != nil {
		t.Fatalf("NewMachine: %v", err)
	}
	bAffection, err := NewAffection(50, 0, 700)
	if err != nil {
		t.Fatalf("NewAffection: %v", err)
	}
	mgr := NewManager()
	mgr.Set("a", aMachine, aAffection)
	mgr.Set("b", bMachine, bAffection)
	obs := NewObserver(mgr, func(string) int { return 10 }, nil)

	if got := obs.Observe("a", "我爱你", true); got != Happy {
		t.Fatalf("persona a mood = %s, want happy", got)
	}
	if bMachine.Current() != Calm || bAffection.Value() != 50 {
		t.Fatalf("persona b = %s/%d, want calm/50 untouched", bMachine.Current(), bAffection.Value())
	}
}