"""Stages 1-3 wired together: a folder of documents in, chunks + manifest out.

    py -m src.knowledge_parsing.run --input data/knowledge_docs/
    py -m src.knowledge_parsing.run --input data/knowledge_docs/ --backend pipeline

Deliberate properties:
  - one document failing does NOT stop the rest (recorded in failures.jsonl)
  - resumable: documents already finished are skipped (--no-resume to force)
  - MinerU's own output is never touched, only pointed at from runs/
"""

from __future__ import annotations

import argparse
import json
import sys
import time
import traceback
from datetime import datetime
from pathlib import Path

from .checks import check_items, vocabulary_per_page
from .config import PipelineConfig
from .contracts import ParsedDocument
from .manifest import DocumentRecord, Manifest
from .normalize import normalise, normaliser_version
from .normalize_mistral import normalise_mistral
from .normalize_mistral import normaliser_version as mistral_normaliser_version
from .parse import file_hash, mineru_version, parse_document

EXTENSIONS = {".pdf", ".docx", ".pptx", ".doc", ".ppt"}


def collect_documents(folder: Path) -> list[Path]:
    return sorted(p for p in folder.rglob("*") if p.suffix.lower() in EXTENSIONS)


def _count(n: int, word: str) -> str:
    """`3 chunks` / `1 chunk` — console output only, never parsed by anything."""
    return f"{n} {word}" if n == 1 else f"{n} {word}s"


def _reject_duplicate_names(documents: list[Path]) -> None:
    """Two files with one name is ambiguous, and the ambiguity is silent.

    `doc_id` is the file name, `chunk_id` is built from `doc_id`, and every
    `term_id` / `formula_id` / `rule_id` downstream is derived from it in turn.
    Two documents sharing a name therefore claim the same identity — and
    because `resume` skips a document whose `chunks.json` already exists, the
    second one is quietly reported as "already present" and never parsed at
    all. The run ends `ok / failed : 2 / 0` with one document missing.

    This fails instead, before any parsing is paid for. It deliberately does
    NOT disambiguate automatically: renaming one to `Laporan_2` would silently
    change the identifier an expert's approve/reject decisions hang on, which
    is a worse failure than stopping and asking.
    """
    by_stem: dict[str, list[Path]] = {}
    for src in documents:
        by_stem.setdefault(src.stem, []).append(src)

    clashes = {stem: paths for stem, paths in by_stem.items() if len(paths) > 1}
    if not clashes:
        return

    lines = ["Two or more documents share one name, and doc_id is built from it:"]
    for stem, paths in sorted(clashes.items()):
        lines.append(f"  '{stem}'")
        lines.extend(f"      {p}" for p in sorted(paths))
    lines.append("  -> rename one, or parse them in separate runs.")
    raise SystemExit("\n".join(lines))


def _warn_identical_content(documents: list[Path]) -> None:
    """Same bytes under two names: legal, wasteful, and worth saying out loud.

    A document downloaded twice arrives as `X.pdf` and `X (2).pdf`. Both are
    real files with different names, so neither this module nor extraction may
    silently drop one — which of them is authoritative is a curation decision.

    But both are parsed (the second free, from the content-addressed cache) and
    both reach extraction as separate documents, so the expert reviews the same
    terms twice with nothing indicating why. Detection is cheap: identical
    content means an identical file hash.
    """
    by_hash: dict[str, list[Path]] = {}
    for src in documents:
        by_hash.setdefault(file_hash(src), []).append(src)

    for paths in by_hash.values():
        if len(paths) > 1:
            print(f"⚠ {len(paths)} documents have identical content:")
            for p in sorted(paths):
                print(f"      {p.name}")
            print("  Both are parsed and both reach extraction as separate documents.")


def run(cfg: PipelineConfig) -> Manifest:
    cfg.validate()
    documents = collect_documents(cfg.input_dir)
    if not documents:
        raise SystemExit(f"No documents found in {cfg.input_dir}")

    # Both run before anything is parsed: a 16-hour batch must not discover a
    # name clash on its last document.
    _reject_duplicate_names(documents)
    _warn_identical_content(documents)

    manifest = Manifest.new(cfg.to_dict())
    manifest.mineru_version = mineru_version()

    run_dir = cfg.runs_dir / manifest.run_id
    run_dir.mkdir(parents=True, exist_ok=True)
    failures = run_dir / "failures.jsonl"

    print(f"Run {manifest.run_id} | backend={cfg.backend} | {_count(len(documents), 'document')}")
    print(f"Output to: {run_dir}\n")

    for n, source in enumerate(documents, 1):
        doc_id = source.stem
        target = run_dir / doc_id
        chunk_file = target / "chunks.json"

        if cfg.resume and chunk_file.exists():
            print(f"[{n}/{len(documents)}] {doc_id} — skipped (already present)")
            continue

        print(f"[{n}/{len(documents)}] {doc_id} … ", end="", flush=True)
        record = DocumentRecord(doc_id=doc_id, source=str(source), status="ok")
        try:
            result = parse_document(source, cfg)
            record.pages = result.pages
            record.parse_seconds = result.seconds
            record.from_cache = result.from_cache
            record.backend_recorded = result.backend_recorded

            if cfg.backend == "mistral":
                response = json.loads(result.content_list.read_text(encoding="utf-8"))
                # MinerU's content-drift check and the word-boundary vocabulary are
                # both MinerU-specific — Mistral emits neither a content_list nor
                # character-spaced formulas, so neither applies.
                record.checks = {"backend": "mistral-ocr"}
                t0 = time.perf_counter()
                chunks = normalise_mistral(response, doc_id)
                record.normalise_seconds = time.perf_counter() - t0
                record.chunk_count = len(chunks)
            else:
                items = json.loads(result.content_list.read_text(encoding="utf-8"))
                # The source PDF goes in too: without something to compare against, a
                # number that changed silently (the EOQ bug) would never be detected.
                record.checks = check_items(
                    items, cfg.min_latex_len,
                    source_pdf=source, page_offset=cfg.start_page,
                )

                # The source page vocabulary, used to restore the word boundaries lost
                # when MinerU writes formulas one character at a time. Re-keyed to
                # MinerU's page indices: page_idx 0 means page `start_page` in the PDF.
                raw_vocabulary = vocabulary_per_page(source)
                vocabulary = (
                    {p - cfg.start_page: words for p, words in raw_vocabulary.items()
                     if p >= cfg.start_page}
                    if raw_vocabulary else None
                )

                t0 = time.perf_counter()
                chunks = normalise(items, doc_id, vocabulary)
                record.normalise_seconds = time.perf_counter() - t0
                record.chunk_count = len(chunks)

            artifact = ParsedDocument(
                doc_id=doc_id,
                # Equal to doc_id today, deliberately separate anyway — see the
                # field's note in contracts.py.
                source_title=source.stem,
                chunks=chunks,
                source_path=str(source),
                content_hash=file_hash(source, length=64),
                n_pages=result.pages,
                parser_name="mistral-ocr" if cfg.backend == "mistral" else "mineru",
                parser_version=result.mineru_version or mineru_version(),
                # backend as the parser actually recorded it, not the config
                parser_backend=result.backend_recorded or cfg.backend,
                parser_config=cfg.fingerprint(),
                # Which normalisation code produced these chunks — the mistral and
                # MinerU normalisers are fingerprinted separately.
                normaliser_version=(
                    mistral_normaliser_version() if cfg.backend == "mistral"
                    else normaliser_version()
                ),
                created_at=datetime.now().isoformat(timespec="seconds"),
                raw_output_dir=str(result.cache_dir),
            )
            target.mkdir(parents=True, exist_ok=True)
            chunk_file.write_text(
                artifact.model_dump_json(indent=2),
                encoding="utf-8",
            )
            # A pointer to MinerU's own output — not copied, so it is not doubled.
            (target / "mineru-source.txt").write_text(
                str(result.cache_dir), encoding="utf-8"
            )

            mark = " (cache)" if result.from_cache else f" {result.seconds:.1f}s"
            warnings = record.checks.get("warning_count", 0)
            mark += f" | {_count(len(chunks), 'chunk')}"
            if warnings:
                mark += f" | ⚠ {_count(warnings, 'warning')}"
            print("ok" + mark)

        except Exception as e:  # one failure must not stop the rest
            record.status = "failed"
            record.error = f"{type(e).__name__}: {e}"
            print(f"FAILED — {record.error}")
            with failures.open("a", encoding="utf-8") as f:
                f.write(json.dumps({
                    "doc_id": doc_id, "source": str(source),
                    "error": record.error, "trace": traceback.format_exc(),
                }, ensure_ascii=False) + "\n")

        manifest.documents.append(record)
        manifest.save(run_dir / "manifest.json")

    s = manifest.summary()
    print("\n--- summary ---")
    print(f"  ok / failed     : {s['documents_ok']} / {s['documents_failed']}")
    print(f"  total pages     : {s['total_pages']}")
    if s["seconds_per_page"]:
        print(f"  seconds/page    : {s['seconds_per_page']}  "
              f"(from {s['pages_measured']} page(s) actually parsed)")
    if s["total_warnings"]:
        print(f"  ⚠ quality warnings: {s['total_warnings']} — see manifest.json")
    print(f"  manifest        : {run_dir / 'manifest.json'}")
    return manifest


def main() -> None:
    # A Windows console defaults to cp1252, which has no "⚠". Without this,
    # printing a quality warning raises UnicodeEncodeError INSIDE the per-document
    # try block — so a document carrying warnings is marked FAILED even though its
    # parse succeeded and was written. The inverse of the intent: the documents
    # whose quality needs attention are the ones thrown away.
    for stream in (sys.stdout, sys.stderr):
        try:
            stream.reconfigure(encoding="utf-8", errors="replace")  # type: ignore[union-attr]
        except (AttributeError, OSError):
            pass

    p = argparse.ArgumentParser(description="Document parsing pipeline (MinerU)")
    p.add_argument("--input", type=Path, help="folder of documents")
    p.add_argument("--backend", choices=["pipeline", "vlm", "hybrid", "mistral"],
                   help="mistral=API, no GPU (default); pipeline=CPU MinerU; "
                        "vlm/hybrid=GPU MinerU")
    p.add_argument("--lang", default=None)
    # `hybrid` only. Not merely fast-vs-thorough: MinerU FORCE-DISABLES image
    # analysis at `medium`, so descriptions exist only at `high` — and always
    # on `vlm`.
    p.add_argument("--effort", choices=["medium", "high"], default=None)
    p.add_argument("--no-resume", action="store_true", help="reprocess everything")
    p.add_argument("--start-page", type=int, default=None)
    p.add_argument("--end-page", type=int, default=None)
    a = p.parse_args()

    cfg = PipelineConfig()
    if a.input:
        cfg.input_dir = a.input
    if a.backend:
        cfg.backend = a.backend
    if a.lang:
        cfg.lang = a.lang
    if a.effort:
        cfg.effort = a.effort
    if a.no_resume:
        cfg.resume = False
    if a.start_page is not None:
        cfg.start_page = a.start_page
    if a.end_page is not None:
        cfg.end_page = a.end_page

    run(cfg)


if __name__ == "__main__":
    main()