import * as fs from 'fs';
import * as path from 'path';
import * as vscode from 'vscode';
import { findBrainFiles, getActiveBrainProfile, openInEditorGroup } from '../utils';
import { getBrainTokenIndex } from '../retrieval';
import { lessonTemplate, lessonSlug, parseLessonFrontmatter, normalizeLessonTitle, bumpLessonOccurrences } from '../retrieval/lessonHelpers';

/**
 * Experience Memory — lesson card 의 *대화형* 명령 (create / manage).
 *
 * 옛 코드: extension.ts 의 `activate()` 안 nested function 3개 (listLessonFiles,
 * createLessonCard, manageLessons). 그러나 셋 다 `activate()` 클로저에서 캡처하는
 * 게 하나도 없었음 (모두 module-level import 만 사용) — nested 인 이유 없음.
 * 분리해 (a) extension.ts 의 activate() 길이 축소, (b) lesson 워크플로우의 단위
 * 테스트 가능, (c) 다른 곳 (예: chat handler) 에서도 직접 호출 가능.
 */

/** All lesson/playbook/qa-finding cards in the active brain. Uses the brain index for the lesson-kind
 *  filter (cheap when warm), then reads only those few files for their frontmatter title/occurrences. */
function listLessonFiles(brainDir: string): Array<{ filePath: string; rel: string; title: string; kind: string; occurrences: number }> {
    const out: Array<{ filePath: string; rel: string; title: string; kind: string; occurrences: number }> = [];
    let files: string[] = [];
    try { files = findBrainFiles(brainDir); } catch { return out; }
    for (const d of getBrainTokenIndex(brainDir, files)) {
        if (!d.kind) continue;
        let content = '';
        try { content = fs.readFileSync(d.filePath, 'utf8').slice(0, 4000); } catch { continue; }
        const fm = parseLessonFrontmatter(content);
        out.push({ filePath: d.filePath, rel: d.relativePath, title: (fm.title || d.title).trim(), kind: d.kind, occurrences: fm.occurrences ?? 1 });
    }
    return out.sort((a, b) => a.rel.localeCompare(b.rel));
}

/** Shared lesson-card creator used by the lesson commands. Dedup-merges into an existing lesson with the same title. */
export async function createLessonCard(situation?: string): Promise<void> {
    const brain = getActiveBrainProfile();
    const brainDir = brain?.localBrainPath;
    if (!brainDir || !path.isAbsolute(brainDir)) {
        vscode.window.showErrorMessage('활성 Second Brain 경로가 설정되지 않았습니다. Settings에서 localBrainPath / brainProfiles를 먼저 설정하세요.');
        return;
    }
    const title = (await vscode.window.showInputBox({
        title: 'New Lesson — Experience Memory',
        prompt: '이 교훈의 제목 (예: "Telegram 원격 실행은 allowlist 필수")',
        placeHolder: '한 줄 요약 — 다음에 같은 실수를 안 하려면 뭘 기억해야 하나',
        ignoreFocusOut: true,
    }))?.trim();
    if (!title) return;
    const today = new Date().toISOString().slice(0, 10);

    // Dedup-merge: a recurring mistake should get LOUDER (occurrences++), not spawn a duplicate card.
    const norm = normalizeLessonTitle(title);
    const existing = norm ? listLessonFiles(brainDir).find((l) => normalizeLessonTitle(l.title) === norm) : undefined;
    if (existing) {
        const pick = await vscode.window.showInformationMessage(
            `이미 같은 제목의 교훈이 있습니다: "${existing.title}" (occurrences: ${existing.occurrences}). 갱신할까요?`,
            { modal: false },
            '갱신 (occurrences +1)', '새로 만들기',
        );
        if (!pick) return;
        if (pick === '갱신 (occurrences +1)') {
            try {
                const cur = fs.readFileSync(existing.filePath, 'utf8');
                fs.writeFileSync(existing.filePath, bumpLessonOccurrences(cur, today), 'utf8');
            } catch (e: any) {
                vscode.window.showErrorMessage(`교훈 갱신 실패: ${e?.message ?? e}`);
                return;
            }
            await openInEditorGroup(existing.filePath);
            vscode.window.showInformationMessage(`기존 교훈을 갱신했습니다 (occurrences: ${existing.occurrences + 1}). 필요하면 내용을 보강하세요.`);
            return;
        }
        // else fall through and create a new one
    }

    const dir = path.join(brainDir, 'lessons');
    try { fs.mkdirSync(dir, { recursive: true }); } catch { /* fall through to error below */ }
    let filePath = path.join(dir, `${today}-${lessonSlug(title)}.md`);
    let n = 2;
    while (fs.existsSync(filePath)) { filePath = path.join(dir, `${today}-${lessonSlug(title)}-${n++}.md`); }
    try {
        fs.writeFileSync(filePath, lessonTemplate(title, today, situation), 'utf8');
        // A-MEM 레슨 네트워크 — 비슷한 과거 교훈과 상호 링크 (실패 무해).
        try {
            const { linkRelatedLessons } = await import('../intelligence/lessonNetwork');
            linkRelatedLessons(brainDir, filePath);
        } catch { /* 링크 실패가 생성을 막지 않음 */ }
    } catch (e: any) {
        vscode.window.showErrorMessage(`교훈 파일 생성 실패: ${e?.message ?? e}`);
        return;
    }
    await openInEditorGroup(filePath);
    vscode.window.showInformationMessage('교훈 카드를 만들었습니다. 내용을 채워 저장하면 다음 유사 작업 시 자동으로 체크리스트에 들어갑니다.');
}

/** Browse lesson cards: open one, or delete one (trash button). Also the "manage" surface for ignoring bad lessons. */
export async function manageLessons(): Promise<void> {
    const brain = getActiveBrainProfile();
    const brainDir = brain?.localBrainPath;
    if (!brainDir || !path.isAbsolute(brainDir)) {
        vscode.window.showErrorMessage('활성 Second Brain 경로가 설정되지 않았습니다.');
        return;
    }
    const lessons = listLessonFiles(brainDir);
    if (lessons.length === 0) {
        const make = await vscode.window.showInformationMessage('아직 교훈 카드가 없습니다.', '새 교훈 만들기');
        if (make) await createLessonCard();
        return;
    }
    const deleteBtn: vscode.QuickInputButton = { iconPath: new vscode.ThemeIcon('trash'), tooltip: '이 교훈 삭제' };
    const qp = vscode.window.createQuickPick<vscode.QuickPickItem & { _file: string }>();
    qp.title = 'Lessons — Experience Memory';
    qp.placeholder = '교훈을 선택하면 열립니다. 휴지통 아이콘으로 삭제. (삭제 = 더 이상 주입 안 됨)';
    qp.items = lessons.map((l) => ({
        label: `$(${l.kind === 'playbook' ? 'book' : l.kind === 'qa-finding' ? 'bug' : 'lightbulb'}) ${l.title}`,
        description: l.occurrences > 1 ? `×${l.occurrences}` : '',
        detail: l.rel,
        buttons: [deleteBtn],
        _file: l.filePath,
    }));
    qp.onDidTriggerItemButton(async (e) => {
        const file = e.item._file;
        const ok = await vscode.window.showWarningMessage(`교훈 "${e.item.label}" 을(를) 삭제할까요?`, { modal: true }, '삭제');
        if (ok === '삭제') {
            try { fs.unlinkSync(file); } catch (err: any) { vscode.window.showErrorMessage(`삭제 실패: ${err?.message ?? err}`); return; }
            qp.items = qp.items.filter((it) => it._file !== file);
            vscode.window.showInformationMessage('교훈을 삭제했습니다.');
            if (qp.items.length === 0) qp.hide();
        }
    });
    qp.onDidAccept(async () => {
        const sel = qp.selectedItems[0];
        qp.hide();
        if (sel) {
            await openInEditorGroup(sel._file);
        }
    });
    qp.onDidHide(() => qp.dispose());
    qp.show();
}