#!/usr/bin/env python
"""Destructively remove beatmapsets from the compact v1 dataset."""

from __future__ import annotations

import argparse
import concurrent.futures
import json
import os
import shutil
import sqlite3
import sys
import time
import uuid
from pathlib import Path
from typing import Any

import pyarrow as pa
import pyarrow.compute as pc
import pyarrow.dataset as ds
import pyarrow.parquet as pq
from tqdm.auto import tqdm

from parquet_writer import PARQUET_WRITE_KWARGS, _atomic_write_parquet


DEFAULT_WORKERS = min(4, max(1, os.cpu_count() or 1))


def _parquet_files(path: Path) -> list[Path]:
    return sorted(p for p in path.rglob("*.parquet") if p.is_file()) if path.exists() else []


def _table(path: Path, columns: list[str]) -> pa.Table:
    files = [str(p) for p in _parquet_files(path)]
    if not files:
        return pa.table({name: [] for name in columns})
    return ds.dataset(files, format="parquet").to_table(columns=columns)


def _hardlink_or_copy(src: Path, dst: Path) -> None:
    dst.parent.mkdir(parents=True, exist_ok=True)
    try:
        os.link(src, dst)
    except OSError:
        shutil.copy2(src, dst)


def _batched(values: list[int], size: int = 500) -> list[list[int]]:
    return [values[i : i + size] for i in range(0, len(values), size)]


def _choose_numeric_set_ids(repo_root: Path, schema_version: str, count: int) -> list[int]:
    latest_dir = repo_root / "data" / schema_version / "all_revisions" / "latest_revisions"
    table = _table(latest_dir, ["set_key"])
    set_ids: set[int] = set()
    for value in table.column("set_key").to_pylist():
        if value is None:
            continue
        text = str(value)
        if text.isdecimal():
            set_id = int(text)
            if set_id > 0:
                set_ids.add(set_id)
    if len(set_ids) < count:
        raise SystemExit(f"only {len(set_ids)} numeric set ids available; cannot remove {count}")
    return sorted(set_ids, reverse=True)[:count]


def _selection_details(
    repo_root: Path,
    schema_version: str,
    selected_set_ids: set[int],
) -> dict[str, Any]:
    all_rev = repo_root / "data" / schema_version / "all_revisions"
    set_table = _table(
        all_rev / "set_revisions",
        ["set_revision_id", "archive_revision_id", "beatmapset_id"],
    )
    set_revision_ids: set[str] = set()
    archive_revision_ids: set[str] = set()
    for row in set_table.to_pylist():
        beatmapset_id = row.get("beatmapset_id")
        if beatmapset_id is None or int(beatmapset_id) not in selected_set_ids:
            continue
        set_revision_ids.add(str(row["set_revision_id"]))
        archive_revision_ids.add(str(row["archive_revision_id"]))

    if not set_revision_ids:
        raise SystemExit("selected set ids did not match any set_revisions rows")

    archive_table = _table(
        all_rev / "archive_revisions",
        ["archive_revision_id", "archive_path", "size_bytes"],
    )
    archive_paths: list[str] = []
    archive_bytes = 0
    for row in archive_table.to_pylist():
        archive_revision_id = str(row["archive_revision_id"])
        if archive_revision_id not in archive_revision_ids:
            continue
        archive_paths.append(str(row["archive_path"]))
        archive_bytes += int(row.get("size_bytes") or 0)

    return {
        "set_ids": sorted(selected_set_ids),
        "set_revision_ids": sorted(set_revision_ids),
        "archive_revision_ids": sorted(archive_revision_ids),
        "archive_paths": sorted(archive_paths),
        "archive_bytes": archive_bytes,
    }


def _filter_one_file(
    src: Path,
    dst: Path,
    root: Path,
    set_values: pa.Array,
    archive_values: pa.Array,
) -> dict[str, Any]:
    table = pq.read_table(src)
    before = table.num_rows
    removed = 0
    if "set_revision_id" in table.column_names:
        keep = pc.invert(pc.is_in(table["set_revision_id"], value_set=set_values))
        table = table.filter(keep)
        removed = before - table.num_rows
    elif "archive_revision_id" in table.column_names:
        keep = pc.invert(pc.is_in(table["archive_revision_id"], value_set=archive_values))
        table = table.filter(keep)
        removed = before - table.num_rows

    if removed == 0:
        _hardlink_or_copy(src, dst)
    elif table.num_rows > 0:
        dst.parent.mkdir(parents=True, exist_ok=True)
        _atomic_write_parquet(table, dst, **PARQUET_WRITE_KWARGS)

    return {
        "file": str(src.relative_to(root)),
        "rows_before": before,
        "rows_after": table.num_rows,
        "rows_removed": removed,
    }


def _rewrite_table_dir(
    repo_root: Path,
    table_dir: Path,
    staging_dir: Path,
    trash_dir: Path,
    set_revision_ids: set[str],
    archive_revision_ids: set[str],
    workers: int,
) -> dict[str, Any]:
    files = _parquet_files(table_dir)
    if not files:
        return {
            "table": table_dir.name,
            "files_before": 0,
            "files_after": 0,
            "rows_before": 0,
            "rows_after": 0,
            "rows_removed": 0,
        }

    set_values = pa.array(sorted(set_revision_ids), type=pa.string())
    archive_values = pa.array(sorted(archive_revision_ids), type=pa.string())
    staged_table = staging_dir / table_dir.name
    staged_table.mkdir(parents=True, exist_ok=True)

    summaries: list[dict[str, Any]] = []
    max_workers = min(max(1, workers), len(files))
    bar = tqdm(
        total=len(files),
        desc=f"remove/{table_dir.name}",
        unit="file",
        file=sys.stderr,
        mininterval=1.0,
        dynamic_ncols=True,
    )
    try:
        if max_workers == 1:
            for src in files:
                dst = staged_table / src.relative_to(table_dir)
                summaries.append(
                    _filter_one_file(src, dst, repo_root, set_values, archive_values)
                )
                bar.update(1)
        else:
            with concurrent.futures.ThreadPoolExecutor(max_workers=max_workers) as ex:
                futures = [
                    ex.submit(
                        _filter_one_file,
                        src,
                        staged_table / src.relative_to(table_dir),
                        repo_root,
                        set_values,
                        archive_values,
                    )
                    for src in files
                ]
                for future in concurrent.futures.as_completed(futures):
                    summaries.append(future.result())
                    bar.update(1)
    finally:
        bar.close()

    table_trash = trash_dir / table_dir.name
    table_trash.parent.mkdir(parents=True, exist_ok=True)
    table_dir.rename(table_trash)
    staged_table.rename(table_dir)

    rows_before = sum(int(s["rows_before"]) for s in summaries)
    rows_after = sum(int(s["rows_after"]) for s in summaries)
    rows_removed = sum(int(s["rows_removed"]) for s in summaries)
    return {
        "table": table_dir.name,
        "files_before": len(files),
        "files_after": len(_parquet_files(table_dir)),
        "rows_before": rows_before,
        "rows_after": rows_after,
        "rows_removed": rows_removed,
    }


def _remove_archive_files(repo_root: Path, archive_paths: list[str]) -> dict[str, int]:
    removed = 0
    missing = 0
    for rel in archive_paths:
        path = repo_root / rel
        if path.exists():
            path.unlink()
            removed += 1
        else:
            missing += 1
    return {"removed": removed, "missing": missing}


def _update_state_db(
    state_db: Path,
    set_ids: list[int],
    *,
    clear_enumerate_state: bool,
) -> dict[str, int]:
    if not state_db.exists():
        return {
            "sets_deleted": 0,
            "attempts_deleted": 0,
            "discoveries_deleted": 0,
            "meta_deleted": 0,
        }
    conn = sqlite3.connect(state_db)
    conn.execute("PRAGMA foreign_keys=ON")
    try:
        attempts_deleted = 0
        discoveries_deleted = 0
        sets_deleted = 0
        for batch in _batched(sorted(set_ids)):
            placeholders = ",".join("?" for _ in batch)
            attempts_deleted += conn.execute(
                f"DELETE FROM mirror_attempts WHERE set_id IN ({placeholders})",
                batch,
            ).rowcount
            discoveries_deleted += conn.execute(
                f"DELETE FROM mirror_discoveries WHERE set_id IN ({placeholders})",
                batch,
            ).rowcount
            sets_deleted += conn.execute(
                f"DELETE FROM sets WHERE set_id IN ({placeholders})",
                batch,
            ).rowcount

        meta_deleted = 0
        if clear_enumerate_state:
            meta_deleted += conn.execute(
                "DELETE FROM meta WHERE key LIKE 'enumerate.high_water.%'"
            ).rowcount
            meta_deleted += conn.execute(
                "DELETE FROM meta WHERE key LIKE 'enumerate.cursor.%'"
            ).rowcount

        conn.commit()
        conn.execute("PRAGMA wal_checkpoint(TRUNCATE)")
    finally:
        conn.close()

    return {
        "sets_deleted": sets_deleted,
        "attempts_deleted": attempts_deleted,
        "discoveries_deleted": discoveries_deleted,
        "meta_deleted": meta_deleted,
    }


def remove_maps_v1(
    repo_root: Path,
    *,
    schema_version: str,
    count: int,
    state_db: Path | None,
    clear_enumerate_state: bool,
    workers: int,
) -> dict[str, Any]:
    repo_root = repo_root.resolve()
    all_revisions = repo_root / "data" / schema_version / "all_revisions"
    if not all_revisions.exists():
        raise FileNotFoundError(all_revisions)

    selected_set_ids = set(_choose_numeric_set_ids(repo_root, schema_version, count))
    details = _selection_details(repo_root, schema_version, selected_set_ids)
    set_revision_ids = set(details["set_revision_ids"])
    archive_revision_ids = set(details["archive_revision_ids"])

    tx_id = f"remove-maps-{int(time.time())}-{uuid.uuid4().hex[:8]}"
    tx_root = repo_root / ".scratch" / "remove-maps-v1" / tx_id
    staging_root = tx_root / "staging" / "all_revisions"
    trash_root = tx_root / "trash" / "all_revisions"
    staging_root.mkdir(parents=True, exist_ok=True)

    table_summaries: list[dict[str, Any]] = []
    try:
        for table_dir in sorted(p for p in all_revisions.iterdir() if p.is_dir()):
            table_summaries.append(
                _rewrite_table_dir(
                    repo_root,
                    table_dir,
                    staging_root,
                    trash_root,
                    set_revision_ids,
                    archive_revision_ids,
                    workers,
                )
            )

        latest_dir = repo_root / "data" / schema_version / "latest"
        if latest_dir.exists():
            shutil.rmtree(latest_dir)

        archive_delete = _remove_archive_files(repo_root, details["archive_paths"])
        state_summary = (
            _update_state_db(
                state_db,
                list(selected_set_ids),
                clear_enumerate_state=clear_enumerate_state,
            )
            if state_db is not None
            else {
                "sets_deleted": 0,
                "attempts_deleted": 0,
                "discoveries_deleted": 0,
                "meta_deleted": 0,
            }
        )
    finally:
        if trash_root.exists():
            shutil.rmtree(trash_root, ignore_errors=True)
        if staging_root.exists():
            shutil.rmtree(staging_root, ignore_errors=True)

    return {
        "ok": True,
        "tx_id": tx_id,
        "requested_count": count,
        "selected_set_count": len(selected_set_ids),
        "selected_set_min": min(selected_set_ids),
        "selected_set_max": max(selected_set_ids),
        "set_revision_count": len(set_revision_ids),
        "archive_revision_count": len(archive_revision_ids),
        "archive_bytes_removed": int(details["archive_bytes"]),
        "archive_files": archive_delete,
        "state": state_summary,
        "tables": table_summaries,
    }


def parse_args(argv: list[str] | None = None) -> argparse.Namespace:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--repo-root", default=".")
    parser.add_argument("--schema-version", default="v1")
    parser.add_argument("--count", type=int, default=1000)
    parser.add_argument("--state-db", default=None)
    parser.add_argument("--clear-enumerate-state", action="store_true")
    parser.add_argument("--workers", type=int, default=DEFAULT_WORKERS)
    parser.add_argument("--summary-path", default=None)
    parser.add_argument("--json", action="store_true")
    return parser.parse_args(argv)


def main(argv: list[str] | None = None) -> int:
    args = parse_args(argv)
    repo_root = Path(args.repo_root).resolve()
    state_db = Path(args.state_db) if args.state_db else None
    if state_db is not None and not state_db.is_absolute():
        state_db = repo_root / state_db

    summary = remove_maps_v1(
        repo_root,
        schema_version=args.schema_version,
        count=args.count,
        state_db=state_db,
        clear_enumerate_state=args.clear_enumerate_state,
        workers=max(1, args.workers),
    )
    text = json.dumps(summary, indent=2, sort_keys=True)
    if args.summary_path:
        path = Path(args.summary_path)
        if not path.is_absolute():
            path = repo_root / path
        path.parent.mkdir(parents=True, exist_ok=True)
        path.write_text(text + "\n", encoding="utf-8")
    if args.json:
        print(text)
    else:
        print(
            "removed "
            f"{summary['selected_set_count']} set(s), "
            f"{summary['archive_revision_count']} archive revision(s), "
            f"{summary['archive_files']['removed']} local archive file(s)"
        )
    return 0


if __name__ == "__main__":
    raise SystemExit(main())