"""
core/system/artifact_retention.py

Artifact Retention & Rotation (Fiche #21)

But : appliquer une politique de rétention simple et sûre sur les artefacts générés
en prod (failure cases, dumps watchdog, guard reports, etc.).

Principe :
- on travaille dans data/ (aucun fichier système)
- on se base sur la date du dossier (YYYY-MM-DD) quand possible, sinon mtime
- on évite les suppressions agressives : par défaut on archive les failure cases

Usage:
    python -m core.system.artifact_retention
    python -m core.system.artifact_retention --dry-run

Variables d'env (optionnel):
    RPA_RETENTION_FAILURE_CASES_DAYS=14
    RPA_RETENTION_WATCHDOG_DAYS=7
    RPA_RETENTION_GUARD_REPORTS_DAYS=30
    RPA_RETENTION_ARCHIVE_FAILURE_CASES=true|false
    RPA_DATA_DIR=data
"""

from __future__ import annotations

import argparse
import logging
import os
import tarfile
from dataclasses import dataclass
from datetime import datetime, timedelta
from pathlib import Path
from typing import Iterable, List, Optional, Tuple

logger = logging.getLogger(__name__)


def _env_int(name: str, default: int) -> int:
    try:
        return int(os.getenv(name, str(default)))
    except Exception:
        return default


def _env_bool(name: str, default: bool) -> bool:
    val = os.getenv(name)
    if val is None:
        return default
    return val.strip().lower() in {"1", "true", "yes", "y", "on"}


def _parse_date_folder(name: str) -> Optional[datetime]:
    """Parse YYYY-MM-DD."""
    try:
        return datetime.strptime(name, "%Y-%m-%d")
    except Exception:
        return None


def _is_older_than(path: Path, cutoff: datetime) -> bool:
    """Décide si un chemin est plus vieux que cutoff."""
    # 1) date dans le chemin (parent YYYY-MM-DD)
    for part in reversed(path.parts):
        dt = _parse_date_folder(part)
        if dt:
            return dt < cutoff
    # 2) fallback mtime
    try:
        return datetime.fromtimestamp(path.stat().st_mtime) < cutoff
    except Exception:
        return False


def _ensure_dir(p: Path) -> None:
    p.mkdir(parents=True, exist_ok=True)


@dataclass(frozen=True)
class RetentionRule:
    name: str
    root: Path
    days: int
    mode: str  # "delete" | "archive_then_delete"


class ArtifactRetention:
    def __init__(self, data_dir: Path, archive_failure_cases: bool = True):
        self.data_dir = data_dir
        self.archive_failure_cases = archive_failure_cases

        self.failure_cases_dir = self.data_dir / "failure_cases"
        self.runtime_dir = self.data_dir / "runtime"
        self.archives_dir = self.data_dir / "archives"

    def _iter_children(self, root: Path) -> Iterable[Path]:
        if not root.exists():
            return []
        # Date folders first, else files/dirs directly
        return list(root.iterdir())

    def _archive_folder(self, folder: Path, archive_root: Path, dry_run: bool) -> Tuple[bool, str]:
        """Archive un dossier en tar.gz, retourne (ok, message)."""
        # Archive path: .../archives/failure_cases/YYYY-MM-DD/<folder>.tar.gz
        date_part = None
        for part in folder.parts:
            if _parse_date_folder(part):
                date_part = part
        date_part = date_part or "undated"
        out_dir = archive_root / date_part
        out_file = out_dir / f"{folder.name}.tar.gz"

        if out_file.exists():
            return True, f"archive exists: {out_file}"

        if dry_run:
            return True, f"would archive -> {out_file}"

        _ensure_dir(out_dir)
        try:
            with tarfile.open(out_file, "w:gz") as tar:
                tar.add(folder, arcname=folder.name)
            return True, f"archived -> {out_file}"
        except Exception as e:
            return False, f"archive failed for {folder}: {e}"

    def _delete_path(self, p: Path, dry_run: bool) -> Tuple[bool, str]:
        if dry_run:
            return True, f"would delete: {p}"
        try:
            if p.is_dir():
                # safe recursive delete
                for child in sorted(p.rglob("*"), reverse=True):
                    try:
                        if child.is_file() or child.is_symlink():
                            child.unlink(missing_ok=True)
                        elif child.is_dir():
                            child.rmdir()
                    except Exception:
                        # best effort
                        pass
                p.rmdir()
            else:
                p.unlink(missing_ok=True)
            return True, f"deleted: {p}"
        except Exception as e:
            return False, f"delete failed for {p}: {e}"

    def apply(self, dry_run: bool = False) -> dict:
        now = datetime.now()

        rules: List[RetentionRule] = [
            RetentionRule(
                name="failure_cases",
                root=self.failure_cases_dir,
                days=_env_int("RPA_RETENTION_FAILURE_CASES_DAYS", 14),
                mode="archive_then_delete" if self.archive_failure_cases else "delete",
            ),
            RetentionRule(
                name="runtime_watchdog",
                root=self.runtime_dir / "watchdog",
                days=_env_int("RPA_RETENTION_WATCHDOG_DAYS", 7),
                mode="delete",
            ),
            RetentionRule(
                name="runtime_guard_reports",
                root=self.runtime_dir / "guard_reports",
                days=_env_int("RPA_RETENTION_GUARD_REPORTS_DAYS", 30),
                mode="delete",
            ),
        ]

        results = {
            "dry_run": dry_run,
            "data_dir": str(self.data_dir),
            "now": now.isoformat(),
            "rules": [],
        }

        for rule in rules:
            cutoff = now - timedelta(days=rule.days)
            rule_res = {
                "name": rule.name,
                "root": str(rule.root),
                "days": rule.days,
                "mode": rule.mode,
                "cutoff": cutoff.isoformat(),
                "touched": [],
                "errors": [],
            }

            for child in self._iter_children(rule.root):
                if not _is_older_than(child, cutoff):
                    continue

                # failure cases: structure date/case_xxx
                if rule.name == "failure_cases":
                    # archive each case folder under date
                    # if we hit a date folder, archive its children
                    if child.is_dir() and _parse_date_folder(child.name):
                        for case_dir in child.iterdir():
                            if not case_dir.is_dir():
                                continue
                            ok, msg = (True, "")
                            if rule.mode == "archive_then_delete":
                                ok, msg = self._archive_folder(
                                    case_dir,
                                    self.archives_dir / "failure_cases",
                                    dry_run,
                                )
                                if not ok:
                                    rule_res["errors"].append(msg)
                                    continue
                                rule_res["touched"].append(msg)
                            ok2, msg2 = self._delete_path(case_dir, dry_run)
                            if ok2:
                                rule_res["touched"].append(msg2)
                            else:
                                rule_res["errors"].append(msg2)
                        # remove date folder if empty
                        try:
                            if not dry_run and child.exists() and not any(child.iterdir()):
                                child.rmdir()
                        except Exception:
                            pass
                        continue

                    # if child is already a case folder, handle it too
                    if child.is_dir():
                        if rule.mode == "archive_then_delete":
                            ok, msg = self._archive_folder(
                                child,
                                self.archives_dir / "failure_cases",
                                dry_run,
                            )
                            if ok:
                                rule_res["touched"].append(msg)
                            else:
                                rule_res["errors"].append(msg)
                                continue
                        ok2, msg2 = self._delete_path(child, dry_run)
                        if ok2:
                            rule_res["touched"].append(msg2)
                        else:
                            rule_res["errors"].append(msg2)
                    continue

                # other rules: delete the child directly (file or folder)
                ok, msg = self._delete_path(child, dry_run)
                if ok:
                    rule_res["touched"].append(msg)
                else:
                    rule_res["errors"].append(msg)

            results["rules"].append(rule_res)

        return results


def main(argv: Optional[List[str]] = None) -> int:
    parser = argparse.ArgumentParser(description="RPA Vision V3 - Artifact retention")
    parser.add_argument("--dry-run", action="store_true", help="ne supprime rien")
    parser.add_argument("--json", action="store_true", help="sortie JSON only")
    args = parser.parse_args(argv)

    logging.basicConfig(level=logging.INFO, format="%(asctime)s [%(levelname)s] %(name)s: %(message)s")

    data_dir = Path(os.getenv("RPA_DATA_DIR", "data"))
    archive_failure_cases = _env_bool("RPA_RETENTION_ARCHIVE_FAILURE_CASES", True)

    retention = ArtifactRetention(data_dir=data_dir, archive_failure_cases=archive_failure_cases)
    res = retention.apply(dry_run=args.dry_run)

    # stdout friendly
    if args.json:
        import json

        print(json.dumps(res, indent=2, ensure_ascii=False))
        return 0

    # pretty summary
    total_touched = sum(len(r["touched"]) for r in res["rules"])
    total_errors = sum(len(r["errors"]) for r in res["rules"])
    logger.info(f"Retention completed. touched={total_touched} errors={total_errors} dry_run={args.dry_run}")
    for r in res["rules"]:
        if r["errors"]:
            logger.warning(f"Rule {r['name']} errors: {len(r['errors'])}")
    return 0 if total_errors == 0 else 2


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