"""
==============================================================================
Skript:   enrich_files_v1.0.py
Verze:    1.0
Datum:    2026-06-03
Autor:    vladimir.buzalka
Popis:    Doplni metadata z obsahu souboru (PDF/DOCX/XLSX/PPTX/EML/MSG)
          do existujicich zaznamu v MongoDB (db: soubory).

          Pole se uklada do podobjektu `content`:
            - common: ok (bool), error (str|None), parsed_at, parser_version
            - pdf:    pages, author, title, subject, creator, producer,
                      created, modified, encrypted, text_head (prvni stranka, max 2000 znaku)
            - docx:   author, title, subject, last_modified_by, paragraphs,
                      words, created, modified, text_head
            - xlsx:   sheets [{name, rows, cols}], total_sheets,
                      author, title, last_modified_by, created, modified
            - pptx:   slides, author, title, subject, last_modified_by,
                      created, modified, text_head (text z prvnich 3 snimku)
            - eml:    subject, from, to, cc, date, has_attachments,
                      attachments [filenames], body_head
            - msg:    same as eml

          Inkrementalni:
            - preskaci soubor, kde content.sha256_at_parse == aktualni sha256
              a content.parser_version == aktualni verze
            - pri zmene obsahu (jiny sha256) prepocita
            - pri chybe ulozi content.error a content.ok=False

MongoDB:  192.168.1.76:27017
DB:       soubory
==============================================================================
"""

from __future__ import annotations

import email
import email.policy
import sys
import time
import traceback
from datetime import datetime, timezone
from pathlib import Path

from pymongo import MongoClient, UpdateOne

MONGO_URI = "mongodb://192.168.1.76:27017"
DB_NAME = "soubory"
COLLECTIONS = ["42847922MDD3003", "77242113UCO3001"]
PARSER_VERSION = "1.0"
TEXT_HEAD_LIMIT = 2000

# limity pro velke soubory - aby skript neuvazil na 1GB PDF
MAX_PDF_BYTES = 500 * 1024 * 1024   # 500 MB
MAX_XLSX_BYTES = 200 * 1024 * 1024
MAX_GENERIC_BYTES = 300 * 1024 * 1024


def _now() -> datetime:
    return datetime.now(tz=timezone.utc)


def _truncate(s: str | None, n: int = TEXT_HEAD_LIMIT) -> str | None:
    if s is None:
        return None
    s = s.strip()
    return s if len(s) <= n else s[:n]


def _to_dt(value):
    if isinstance(value, datetime):
        return value if value.tzinfo else value.replace(tzinfo=timezone.utc)
    if isinstance(value, str) and value:
        try:
            return datetime.fromisoformat(value.replace("Z", "+00:00"))
        except ValueError:
            return None
    return None


# --- PARSERY ----------------------------------------------------------------

def parse_pdf(path: Path) -> dict:
    from pypdf import PdfReader
    reader = PdfReader(str(path))
    info = reader.metadata or {}
    out = {
        "pages": len(reader.pages),
        "encrypted": reader.is_encrypted,
        "author": getattr(info, "author", None),
        "title": getattr(info, "title", None),
        "subject": getattr(info, "subject", None),
        "creator": getattr(info, "creator", None),
        "producer": getattr(info, "producer", None),
        "created": _to_dt(getattr(info, "creation_date", None)),
        "modified": _to_dt(getattr(info, "modification_date", None)),
    }
    text_head = None
    try:
        if not reader.is_encrypted and reader.pages:
            text_head = reader.pages[0].extract_text()
    except Exception:
        text_head = None
    out["text_head"] = _truncate(text_head)
    return out


def parse_docx(path: Path) -> dict:
    from docx import Document
    doc = Document(str(path))
    core = doc.core_properties
    paragraphs = doc.paragraphs
    text = "\n".join(p.text for p in paragraphs if p.text)
    words = len(text.split())
    return {
        "author": core.author,
        "title": core.title,
        "subject": core.subject,
        "last_modified_by": core.last_modified_by,
        "paragraphs": len(paragraphs),
        "words": words,
        "created": _to_dt(core.created),
        "modified": _to_dt(core.modified),
        "text_head": _truncate(text),
    }


def parse_xlsx(path: Path) -> dict:
    from openpyxl import load_workbook
    wb = load_workbook(str(path), read_only=True, data_only=False)
    sheets = []
    for ws in wb.worksheets:
        sheets.append({
            "name": ws.title,
            "rows": ws.max_row,
            "cols": ws.max_column,
        })
    props = wb.properties
    out = {
        "total_sheets": len(sheets),
        "sheets": sheets,
        "author": props.creator,
        "title": props.title,
        "subject": props.subject,
        "last_modified_by": props.lastModifiedBy,
        "created": _to_dt(props.created),
        "modified": _to_dt(props.modified),
    }
    wb.close()
    return out


def parse_pptx(path: Path) -> dict:
    from pptx import Presentation
    prs = Presentation(str(path))
    core = prs.core_properties
    head_parts = []
    for slide in list(prs.slides)[:3]:
        for shape in slide.shapes:
            if shape.has_text_frame:
                for para in shape.text_frame.paragraphs:
                    for run in para.runs:
                        if run.text:
                            head_parts.append(run.text)
    return {
        "slides": len(prs.slides),
        "author": core.author,
        "title": core.title,
        "subject": core.subject,
        "last_modified_by": core.last_modified_by,
        "created": _to_dt(core.created),
        "modified": _to_dt(core.modified),
        "text_head": _truncate(" ".join(head_parts)),
    }


def parse_eml(path: Path) -> dict:
    with path.open("rb") as f:
        msg = email.message_from_binary_file(f, policy=email.policy.default)
    attachments = []
    body_parts = []
    if msg.is_multipart():
        for part in msg.walk():
            disp = (part.get("Content-Disposition") or "").lower()
            ctype = part.get_content_type()
            if "attachment" in disp or part.get_filename():
                fname = part.get_filename()
                if fname:
                    attachments.append(fname)
            elif ctype == "text/plain":
                try:
                    body_parts.append(part.get_content())
                except Exception:
                    pass
    else:
        try:
            body_parts.append(msg.get_content())
        except Exception:
            pass

    def _addrs(field):
        v = msg.get(field)
        return v if v else None

    return {
        "subject": msg.get("Subject"),
        "from": _addrs("From"),
        "to": _addrs("To"),
        "cc": _addrs("Cc"),
        "date": msg.get("Date"),
        "has_attachments": bool(attachments),
        "attachments": attachments,
        "body_head": _truncate("\n".join(body_parts)),
    }


def parse_msg(path: Path) -> dict:
    import extract_msg
    with extract_msg.openMsg(str(path)) as msg:
        attachments = []
        for att in msg.attachments or []:
            try:
                fname = att.longFilename or att.shortFilename
                if fname:
                    attachments.append(fname)
            except Exception:
                continue
        return {
            "subject": msg.subject,
            "from": msg.sender,
            "to": msg.to,
            "cc": msg.cc,
            "date": str(msg.date) if msg.date else None,
            "has_attachments": bool(attachments),
            "attachments": attachments,
            "body_head": _truncate(msg.body or ""),
        }


PARSERS = {
    "pdf": (parse_pdf, MAX_PDF_BYTES),
    "docx": (parse_docx, MAX_GENERIC_BYTES),
    "xlsx": (parse_xlsx, MAX_XLSX_BYTES),
    "xlsm": (parse_xlsx, MAX_XLSX_BYTES),
    "pptx": (parse_pptx, MAX_GENERIC_BYTES),
    "eml": (parse_eml, MAX_GENERIC_BYTES),
    "msg": (parse_msg, MAX_GENERIC_BYTES),
}


# --- SUMMARY PRO KONZOLI ----------------------------------------------------

def _short(s, n=40):
    if not s:
        return ""
    s = str(s).replace("\n", " ").replace("\r", " ").strip()
    return s if len(s) <= n else s[:n] + "..."


def _summary(content: dict, ext: str) -> str:
    if not content.get("ok"):
        return f"chyba: {_short(content.get('error'), 80)}"
    parts = []
    if ext == "pdf":
        parts.append(f"{content.get('pages')}p")
        if content.get("encrypted"): parts.append("enc")
        if content.get("author"): parts.append(f"by={_short(content['author'], 25)}")
        if content.get("title"): parts.append(f"t={_short(content['title'], 30)}")
    elif ext == "docx":
        parts.append(f"{content.get('paragraphs')}para")
        parts.append(f"{content.get('words')}w")
        if content.get("author"): parts.append(f"by={_short(content['author'], 25)}")
    elif ext in ("xlsx", "xlsm"):
        n = content.get("total_sheets", 0)
        sheets = content.get("sheets") or []
        names = ",".join(_short(s["name"], 12) for s in sheets[:3])
        if n > 3:
            names += f",+{n-3}"
        parts.append(f"{n}sh[{names}]")
        if content.get("author"): parts.append(f"by={_short(content['author'], 20)}")
    elif ext == "pptx":
        parts.append(f"{content.get('slides')}slides")
        if content.get("author"): parts.append(f"by={_short(content['author'], 25)}")
        if content.get("title"): parts.append(f"t={_short(content['title'], 25)}")
    elif ext in ("eml", "msg"):
        if content.get("from"): parts.append(f"from={_short(content['from'], 25)}")
        if content.get("subject"): parts.append(f"subj={_short(content['subject'], 40)}")
        if content.get("has_attachments"):
            parts.append(f"att={len(content.get('attachments') or [])}")
    return " ".join(parts) if parts else "ok"


# --- HLAVNI SMYCKA ----------------------------------------------------------

def enrich_collection(coll, study: str) -> dict:
    supported = list(PARSERS.keys())
    query = {
        "ext": {"$in": supported},
        "deleted_at": {"$exists": False},
        "$or": [
            {"content": {"$exists": False}},
            {"content.parser_version": {"$ne": PARSER_VERSION}},
            {"$expr": {"$ne": ["$content.sha256_at_parse", "$sha256"]}},
        ],
    }
    total_pending = coll.count_documents(query)
    print(f"[{study}] k zpracovani: {total_pending} souboru")

    ops: list[UpdateOne] = []
    processed = 0
    ok = 0
    errors = 0
    too_big = 0

    cursor = coll.find(query, {"path": 1, "ext": 1, "size_bytes": 1, "sha256": 1}, no_cursor_timeout=True)
    try:
        for doc in cursor:
            ext = doc["ext"]
            parser, max_bytes = PARSERS[ext]
            path = Path(doc["path"])
            content: dict = {
                "parser_version": PARSER_VERSION,
                "parsed_at": _now(),
                "sha256_at_parse": doc.get("sha256"),
            }
            if not path.exists():
                content.update(ok=False, error="file_missing")
                errors += 1
            elif doc.get("size_bytes", 0) > max_bytes:
                content.update(ok=False, error=f"too_big_>{max_bytes}")
                too_big += 1
            else:
                try:
                    payload = parser(path)
                    content["ok"] = True
                    content.update(payload)
                    ok += 1
                except Exception as e:
                    content["ok"] = False
                    content["error"] = f"{type(e).__name__}: {e}"[:500]
                    errors += 1

            ops.append(UpdateOne({"_id": doc["_id"]}, {"$set": {"content": content}}))
            processed += 1

            status = "OK " if content.get("ok") else ("BIG" if "too_big" in (content.get("error") or "") else "ERR")
            size_mb = (doc.get("size_bytes", 0) or 0) / 1024 / 1024
            detail = _summary(content, ext)
            print(f"  [{processed:>4}/{total_pending}] {status} {ext:<4} {size_mb:6.1f}MB  {path.name}  | {detail}", flush=True)

            if len(ops) >= 50:
                coll.bulk_write(ops, ordered=False)
                ops.clear()
    finally:
        cursor.close()

    if ops:
        coll.bulk_write(ops, ordered=False)

    return {"study": study, "processed": processed, "ok": ok, "errors": errors, "too_big": too_big}


def main() -> int:
    t0 = time.time()
    client = MongoClient(MONGO_URI, serverSelectionTimeoutMS=5000)
    client.admin.command("ping")
    db = client[DB_NAME]

    results = []
    for name in COLLECTIONS:
        results.append(enrich_collection(db[name], name))

    print("\n=== SHRNUTI ===")
    for r in results:
        print(f"  {r['study']}: processed={r['processed']}  ok={r['ok']}  "
              f"errors={r['errors']}  too_big={r['too_big']}")
    print(f"\nCelkem trvalo: {time.time() - t0:.1f} s")
    return 0


if __name__ == "__main__":
    try:
        raise SystemExit(main())
    except KeyboardInterrupt:
        print("\nPreruseno uzivatelem")
    except Exception:
        traceback.print_exc()
        sys.exit(1)