"""텍스트 추출 워커 — kordoc / PyMuPDF / Surya OCR / LibreOffice / 직접 읽기"""

import re
import subprocess
from datetime import datetime, timezone
from pathlib import Path

import httpx
from sqlalchemy.ext.asyncio import AsyncSession

from core.config import settings
from core.utils import setup_logger
from models.document import Document

logger = setup_logger("extract_worker")

# kordoc으로 파싱 가능한 포맷
KORDOC_FORMATS = {"hwp", "hwpx", "pdf"}
# 직접 읽기 가능한 텍스트 포맷
TEXT_FORMATS = {"md", "txt", "csv", "json", "xml", "html"}
# LibreOffice로 텍스트 추출 가능한 포맷
OFFICE_FORMATS = {"xlsx", "xls", "docx", "doc", "pptx", "ppt", "odt", "ods", "odp", "odoc", "osheet"}
# OCR 대상 이미지 포맷
IMAGE_FORMATS = {"jpg", "jpeg", "png", "tiff", "tif", "bmp", "gif", "webp"}

EXTRACTOR_VERSION = "kordoc@1.7"
PYMUPDF_VERSION = "pymupdf"


# ─── OCR 판정 함수 ───

def _should_ocr(text: str, page_count: int) -> tuple[bool, str]:
    """텍스트 추출 결과로 OCR 필요 여부 판정 — 2단계"""
    total = len(text.strip())
    if total < 300:
        return True, "no_text_layer"
    avg = total / max(page_count, 1)
    if avg < 80 and total < 3000:
        return True, "low_text_density"
    return False, ""


def _ocr_skip_reason(file_size: int, page_count: int) -> str | None:
    """OCR 상한 체크"""
    if page_count > 200:
        return "page_limit"
    if file_size > 150 * 1024 * 1024:
        return "size_limit"
    return None


def _ocr_quality_ok(text: str, page_count: int, is_image: bool) -> bool:
    """OCR 결과 품질 검증 — 유형별 차등"""
    chars = len(text.strip())
    if is_image:
        return chars >= 50
    if page_count > 0:
        return chars >= 200 or (chars / max(page_count, 1)) >= 30
    return chars >= 200


def _postprocess_ocr(text: str) -> str:
    """OCR 후처리 — NUL 제거 + 과도한 공백 정리"""
    text = text.replace("\x00", "")
    text = re.sub(r'\s{3,}', '\n', text)
    return text.strip()


def _extract_pdf_pymupdf(file_path: Path) -> str:
    """PyMuPDF fallback — 페이지 단위 스트리밍으로 대형 PDF도 저메모리 처리"""
    import fitz
    text_parts = []
    with fitz.open(str(file_path)) as doc:
        for page in doc:
            text_parts.append(page.get_text())
    return "\n".join(text_parts)


def _get_pdf_page_count(file_path: Path) -> int:
    """PDF 페이지 수 확인"""
    import fitz
    with fitz.open(str(file_path)) as doc:
        return len(doc)


async def _call_ocr(file_path: Path, is_image: bool, max_pages: int = 200) -> str | None:
    """OCR 서비스 호출 — 타임아웃 페이지 수 비례"""
    container_path = f"/documents/{file_path.relative_to(Path(settings.nas_mount_path))}"
    timeout = 60 if is_image else min(600, max(120, max_pages * 3))
    try:
        async with httpx.AsyncClient(timeout=timeout) as client:
            resp = await client.post(
                f"{settings.ocr_endpoint}/ocr",
                json={"filePath": container_path, "langs": ["ko", "en"], "maxPages": max_pages},
            )
        if resp.status_code == 200:
            data = resp.json()
            return data.get("text", "")
    except Exception as e:
        logger.error(f"[ocr] OCR 서비스 호출 실패: {e}")
    return None


# ─── 메인 처리 ───

async def process(document_id: int, session: AsyncSession) -> None:
    """문서 텍스트 추출"""
    doc = await session.get(Document, document_id)
    if not doc:
        raise ValueError(f"문서 ID {document_id}를 찾을 수 없음")

    fmt = doc.file_format.lower()
    full_path = Path(settings.nas_mount_path) / doc.file_path

    # ─── 텍스트 파일 — 직접 읽기 ───
    if fmt in TEXT_FORMATS:
        if not full_path.exists():
            raise FileNotFoundError(f"파일 없음: {full_path}")
        text = full_path.read_text(encoding="utf-8", errors="replace")
        doc.extracted_text = text.replace("\x00", "")
        doc.extracted_at = datetime.now(timezone.utc)
        doc.extractor_version = "direct_read"
        logger.info(f"[텍스트] {doc.file_path} ({len(text)}자)")
        return

    # ─── 이미지 — OCR ───
    if fmt in IMAGE_FORMATS:
        meta = doc.extract_meta or {}

        # OCR 1회 제한
        if meta.get("ocr_attempted"):
            meta["ocr_skip_reason"] = "already_attempted"
            doc.extract_meta = meta
            logger.info(f"[이미지] {doc.file_path} — OCR 이미 시도됨, 스킵")
            return

        # 상한 체크
        skip = _ocr_skip_reason(doc.file_size or 0, 1)
        if skip:
            doc.extracted_text = ""
            doc.extractor_version = None
            doc.extract_meta = {**meta, "ocr_skip_reason": skip, "ocr_terminal": True}
            doc.extracted_at = datetime.now(timezone.utc)
            logger.warning(f"[이미지] {doc.file_path} — OCR 스킵 ({skip})")
            return

        # OCR 서비스 호출
        ocr_text = await _call_ocr(full_path, is_image=True)
        meta["ocr_attempted"] = True
        meta["ocr_reason"] = "image_file"

        if ocr_text and _ocr_quality_ok(ocr_text, 1, is_image=True):
            doc.extracted_text = _postprocess_ocr(ocr_text)
            doc.extractor_version = "surya_ocr"
            meta["ocr_chars"] = len(doc.extracted_text)
            logger.info(f"[surya_ocr] {doc.file_path} ({len(doc.extracted_text)}자)")
        else:
            doc.extracted_text = ""
            doc.extractor_version = None
            meta["ocr_quality_ok"] = False
            meta["ocr_terminal"] = True
            logger.warning(f"[이미지] {doc.file_path} — OCR 결과 품질 미달")

        doc.extract_meta = meta
        doc.extracted_at = datetime.now(timezone.utc)
        return

    # ─── kordoc 파싱 (HWP/HWPX/PDF) + PyMuPDF fallback + OCR ───
    if fmt in KORDOC_FORMATS:
        container_path = f"/documents/{doc.file_path}"
        kordoc_timeout = min(300, max(60, (doc.file_size or 0) // (10 * 1024 * 1024) * 60 + 60))

        kordoc_ok = False
        try:
            async with httpx.AsyncClient(timeout=kordoc_timeout) as client:
                resp = await client.post(
                    f"{settings.kordoc_endpoint}/parse",
                    json={"filePath": container_path},
                )

            if resp.status_code == 404:
                raise FileNotFoundError(f"kordoc: 파일 없음 — {container_path}")

            if resp.status_code == 200:
                data = resp.json()
                text = data.get("markdown", "").replace("\x00", "")
                if text:
                    doc.extracted_text = text
                    doc.extracted_at = datetime.now(timezone.utc)
                    doc.extractor_version = EXTRACTOR_VERSION
                    logger.info(f"[kordoc] {doc.file_path} ({len(text)}자)")
                    kordoc_ok = True

        except FileNotFoundError:
            raise
        except Exception as e:
            logger.warning(f"[kordoc] {doc.file_path} 실패 ({e.__class__.__name__}), fallback 시도")

        if kordoc_ok:
            return

        # ─── PyMuPDF fallback (PDF만) ───
        if fmt == "pdf" and full_path.exists():
            try:
                pymupdf_text = _extract_pdf_pymupdf(full_path)
                page_count = _get_pdf_page_count(full_path)
            except Exception as e:
                logger.error(f"[pymupdf] {doc.file_path} 실패: {e}")
                pymupdf_text = ""
                page_count = 0

            meta = doc.extract_meta or {}
            meta["pymupdf_chars"] = len(pymupdf_text.strip())

            # PyMuPDF 텍스트 충분 여부 판정
            should, reason = _should_ocr(pymupdf_text, page_count)

            if not should:
                # PyMuPDF 텍스트 충분 → OCR 불필요
                doc.extracted_text = pymupdf_text.replace("\x00", "")
                doc.extracted_at = datetime.now(timezone.utc)
                doc.extractor_version = PYMUPDF_VERSION
                doc.extract_meta = meta
                logger.info(f"[pymupdf] {doc.file_path} ({len(pymupdf_text)}자)")
                return

            # ─── OCR 필요 ───

            # OCR 1회 제한
            if meta.get("ocr_attempted"):
                doc.extracted_text = pymupdf_text.replace("\x00", "") or ""
                doc.extracted_at = datetime.now(timezone.utc)
                doc.extractor_version = "pymupdf" if pymupdf_text.strip() else None
                meta["ocr_skip_reason"] = "already_attempted"
                doc.extract_meta = meta
                logger.info(f"[pdf] {doc.file_path} — OCR 이미 시도됨, PyMuPDF 결과 유지")
                return

            # 상한 체크
            skip = _ocr_skip_reason(doc.file_size or 0, page_count)
            if skip:
                doc.extracted_text = pymupdf_text.replace("\x00", "") or ""
                doc.extracted_at = datetime.now(timezone.utc)
                doc.extractor_version = "pymupdf" if pymupdf_text.strip() else None
                doc.extract_meta = {**meta, "ocr_skip_reason": skip, "ocr_terminal": not pymupdf_text.strip()}
                logger.warning(f"[pdf] {doc.file_path} — OCR 스킵 ({skip}), PyMuPDF 결과 유지")
                return

            # OCR 서비스 호출
            meta["ocr_attempted"] = True
            meta["ocr_reason"] = reason
            logger.info(f"[pdf] {doc.file_path} — OCR 시도 (reason={reason}, pages={page_count})")

            ocr_text = await _call_ocr(full_path, is_image=False, max_pages=min(page_count, 200))

            if ocr_text and _ocr_quality_ok(ocr_text, page_count, is_image=False):
                doc.extracted_text = _postprocess_ocr(ocr_text)
                doc.extractor_version = "surya_ocr"
                meta["ocr_chars"] = len(doc.extracted_text)
                logger.info(f"[surya_ocr] {doc.file_path} ({len(doc.extracted_text)}자)")
            else:
                # OCR 실패 → PyMuPDF 텍스트라도 보존
                doc.extracted_text = pymupdf_text.replace("\x00", "") or ""
                doc.extractor_version = "pymupdf" if pymupdf_text.strip() else None
                meta["ocr_quality_ok"] = False
                if not pymupdf_text.strip():
                    meta["ocr_terminal"] = True
                logger.warning(f"[pdf] {doc.file_path} — OCR 결과 품질 미달, PyMuPDF 결과 유지")

            doc.extract_meta = meta
            doc.extracted_at = datetime.now(timezone.utc)
            return

        # HWP/HWPX는 kordoc 전용 — fallback 없음
        if fmt != "pdf":
            raise ValueError(f"kordoc 파싱 실패 (HWP/HWPX는 fallback 없음)")
        raise ValueError(f"PDF 텍스트 추출 실패 — kordoc + PyMuPDF 모두 실패")

    # ─── 오피스 포맷 — LibreOffice 텍스트 변환 ───
    if fmt in OFFICE_FORMATS:
        if not full_path.exists():
            raise FileNotFoundError(f"파일 없음: {full_path}")

        import shutil
        tmp_dir = Path("/tmp/extract_work")
        tmp_dir.mkdir(exist_ok=True)

        tmp_input = tmp_dir / f"input_{document_id}.{fmt}"
        shutil.copy2(str(full_path), str(tmp_input))

        CALC_FORMATS = {"xlsx", "xls", "ods", "osheet"}
        if fmt in CALC_FORMATS:
            convert_to = "csv:Text - txt - csv (StarCalc):44,34,76,1"
            out_ext = "csv"
        else:
            convert_to = "txt:Text"
            out_ext = "txt"

        try:
            result = subprocess.run(
                ["libreoffice", "--headless", "--convert-to", convert_to, "--outdir", str(tmp_dir), str(tmp_input)],
                capture_output=True, text=True, timeout=60,
            )
            out_file = tmp_dir / f"input_{document_id}.{out_ext}"
            if out_file.exists():
                text = out_file.read_text(encoding="utf-8", errors="replace")
                # 설계 원칙: extract는 전체 텍스트 저장. classify/summarize가 자체 상한으로 slice.
                doc.extracted_text = text.replace("\x00", "")
                doc.extracted_at = datetime.now(timezone.utc)
                doc.extractor_version = "libreoffice"
                out_file.unlink()
                logger.info(f"[LibreOffice] {doc.file_path} ({len(text)}자)")
            else:
                raise RuntimeError(f"LibreOffice 변환 실패: {result.stderr[:300]}")
        except subprocess.TimeoutExpired:
            raise RuntimeError(f"LibreOffice 텍스트 추출 timeout (60s)")
        finally:
            tmp_input.unlink(missing_ok=True)

        # ─── ODF 변환 (편집용) ───
        CONVERT_MAP = {
            'xlsx': 'ods', 'xls': 'ods',
            'docx': 'odt', 'doc': 'odt',
            'pptx': 'odp', 'ppt': 'odp',
        }
        target_fmt = CONVERT_MAP.get(fmt)
        if target_fmt:
            try:
                derived_dir = full_path.parent / ".derived"
                derived_dir.mkdir(exist_ok=True)
                tmp_input2 = tmp_dir / f"convert_{document_id}.{fmt}"
                shutil.copy2(str(full_path), str(tmp_input2))

                conv_result = subprocess.run(
                    ["libreoffice", "--headless", "--convert-to", target_fmt, "--outdir", str(tmp_dir), str(tmp_input2)],
                    capture_output=True, text=True, timeout=60,
                )
                tmp_input2.unlink(missing_ok=True)

                conv_file = tmp_dir / f"convert_{document_id}.{target_fmt}"
                if conv_file.exists():
                    final_path = derived_dir / f"{document_id}.{target_fmt}"
                    shutil.move(str(conv_file), str(final_path))

                    nas_root = Path(settings.nas_mount_path)
                    doc.derived_path = str(final_path.relative_to(nas_root))
                    doc.original_format = doc.file_format
                    doc.conversion_status = "done"
                    logger.info(f"[ODF변환] {doc.file_path} → derived: {doc.derived_path}")
                else:
                    doc.conversion_status = "failed"
                    logger.warning(f"[ODF변환] 실패: {conv_result.stderr[:200]}")
            except Exception as e:
                doc.conversion_status = "failed"
                logger.error(f"[ODF변환] {doc.file_path} 에러: {e}")
        else:
            doc.conversion_status = "none"

        return

    # ─── 미지원 포맷 ───
    doc.extracted_text = ""
    doc.extracted_at = datetime.now(timezone.utc)
    doc.extractor_version = f"unsupported_{fmt}"
    logger.warning(f"[미지원] {doc.file_path} (format={fmt})")