"""Upload blueprint — загрузка, конвертация, распаковка."""
import io, os, base64, hashlib, zipfile
import httpx
from flask import Blueprint, request, jsonify, send_file
from services.parse import parse_file
from db import documents
import config

upload_bp = Blueprint("upload", __name__)

ALLOWED = {"pdf", "docx", "doc", "zip"}


def _check_ext(filename: str) -> str | None:
    ext = filename.rsplit(".", 1)[-1].lower() if "." in filename else ""
    if ext not in ALLOWED:
        return f"unsupported format: .{ext} (allowed: {', '.join(sorted(ALLOWED))})"
    return None


@upload_bp.route("/upload", methods=["POST"])
def upload():
    """Загрузка одного файла + авто-парсинг → БД."""
    f = request.files.get("files")
    if not f:
        return jsonify(ok=False, error="no file"), 400

    err = _check_ext(f.filename)
    if err:
        return jsonify(ok=False, error=err), 400

    data = f.read()
    content_hash = hashlib.sha256(data).hexdigest()[:16]
    batch_id = request.form.get("batch_id")
    zip_source = request.form.get("zip_source")

    # Дедупликация по хешу
    if batch_id:
        existing = documents.get_by_hash(batch_id, content_hash)
        if existing:
            return jsonify(ok=False, error="duplicate", doc_id=existing["id"])

    doc = documents.insert(
        filename=f.filename,
        mime_type=f.content_type or "application/octet-stream",
        original_bytes=base64.b64encode(data).decode(),
        batch_id=batch_id,
        zip_source=zip_source,
        content_hash=content_hash,
    )

    # Авто-парсинг
    try:
        result = parse_file(f.filename, data)
        if result["status"] == "parsed":
            documents.set_parsed(doc["id"], result["elements"])
        else:
            documents.set_error(doc["id"], result.get("error", "parse failed"))
    except Exception as e:
        documents.set_error(doc["id"], str(e))
        result = {"status": "error", "error": str(e)}

    contract_id = request.form.get("contract_id")
    return jsonify(
        ok=True,
        doc_id=doc["id"],
        contract_id=contract_id,
        parsed={"status": result["status"], "element_count": result.get("element_count", 0)},
    )


@upload_bp.route("/convert-doc", methods=["POST"])
def convert_doc():
    """.doc → .docx через внешний libreoffice-сервис (HTTP)."""
    f = request.files.get("files")
    if not f:
        return jsonify(ok=False, error="no file"), 400

    try:
        resp = httpx.post(
            config.CONVERT_SERVICE_URL + "/convert",
            files={"file": (f.filename, f.read(), f.content_type or "application/msword")},
            timeout=120,
        )
        if resp.status_code == 200:
            return send_file(
                io.BytesIO(resp.content),
                mimetype="application/vnd.openxmlformats-officedocument.wordprocessingml.document",
            )
        data = resp.json()
        return jsonify(ok=False, error=data.get("error", "conversion failed")), 500
    except httpx.TimeoutException:
        return jsonify(ok=False, error="conversion timeout"), 500
    except Exception as e:
        return jsonify(ok=False, error=str(e)), 500


@upload_bp.route("/unzip-upload", methods=["POST"])
def unzip_upload():
    """Распаковать ZIP → список файлов (base64 для фронтенда)."""
    f = request.files.get("files")
    if not f:
        return jsonify(ok=False, error="no file"), 400

    data = f.read()
    MAX_FILES = 500
    MAX_UNCOMPRESSED = 500 * 1024 * 1024  # 500 MB

    files = []
    total = 0

    with zipfile.ZipFile(io.BytesIO(data)) as zf:
        if len(zf.namelist()) > MAX_FILES:
            return jsonify(ok=False, error=f"too many files in ZIP (max {MAX_FILES})"), 400

        for info in zf.infolist():
            if info.is_dir():
                continue
            name = os.path.basename(info.filename)
            if not name or ".." in name or "/" in name or "\\" in name:
                continue

            raw = zf.read(info)
            total += len(raw)
            if total > MAX_UNCOMPRESSED:
                return jsonify(ok=False, error="total uncompressed size exceeds 500 MB"), 400

            ext = name.rsplit(".", 1)[-1].lower() if "." in name else ""
            files.append({
                "filename": name,
                "ext": ext,
                "size": len(raw),
                "data_b64": base64.b64encode(raw).decode(),
            })

    return jsonify(ok=True, files=files)