package phraser

import (
	"errors"
	"strings"
	"testing"
)

// A reply that starts a JSON object and never finishes it is a failed
// generation, not a reply. Before this, the parser returned ("", "") for these
// and every caller then shipped the raw fragment as the thing Maven said. A
// real run produced replies of literally "{" and "{\n  \"".
func TestParseResponseMoodRejectsUnfinishedJSON(t *testing.T) {
	for _, raw := range []string{
		`{`,
		"{\n  \"",
		`{"response": "неполн`,
		`{"response": "текст", "mood":`,
	} {
		text, mood, err := parseResponseMood(raw)
		if !errors.Is(err, errBrokenJSON) {
			t.Errorf("parseResponseMood(%q) err = %v, want errBrokenJSON", raw, err)
		}
		if text != "" || mood != "" {
			t.Errorf("parseResponseMood(%q) leaked %q/%q — a fragment must never come back as a reply", raw, text, mood)
		}
	}
}

// Bare prose is still fine. Small models sometimes answer without any JSON at
// all, and that reply is usable — so the new error must not swallow it.
func TestParseResponseMoodAllowsBareProse(t *testing.T) {
	for _, raw := range []string{
		"норм, а ты как?",
		"вот что я нашла: ключ у соседа",
	} {
		text, mood, err := parseResponseMood(raw)
		if err != nil {
			t.Errorf("parseResponseMood(%q) err = %v, want nil", raw, err)
		}
		// No JSON means no fields; the caller ships raw as-is.
		if text != "" || mood != "" {
			t.Errorf("parseResponseMood(%q) = %q/%q, want empty", raw, text, mood)
		}
	}
}

// The measured failure: the model wants more than 400 characters and the old
// grammar cut it off mid-word. Guards the bound against being tightened back.
func TestGrammarStringBoundHasRoomForARealAnswer(t *testing.T) {
	if !strings.Contains(responseGrammar, "{0,1000}") {
		t.Error("grammar string bound is not 1000; 400 truncated real replies mid-word (see the comment on responseGrammar)")
	}
}