"""Locations and non-destructive retention for local operational reports."""

from __future__ import annotations

import hashlib
import json
from datetime import datetime, timezone
from pathlib import Path
from uuid import uuid4

from tools.rag.common import DATA_DIR

CORE_JSON = {"documents.json", "chunks.json", "index_version.json"}


def run_id() -> str:
    return datetime.now(timezone.utc).strftime("%Y%m%dT%H%M%SZ") + "-" + uuid4().hex[:8]


def report_output(requested: Path | None, category: str, *, data_dir: Path = DATA_DIR) -> Path:
    if not category.replace("_", "").isalnum():
        raise ValueError("Invalid report category")
    if requested is None:
        target = data_dir / "reports" / category / (run_id() + ".json")
    else:
        target = requested.resolve()
        if target.parent == data_dir.resolve():
            if target.name in CORE_JSON or target.name.startswith(".") or target.suffix != ".json":
                raise ValueError("Report cannot overwrite operational data")
            target = data_dir / "reports" / category / target.name
    if target.exists():
        raise FileExistsError(f"Report already exists: {target}")
    target.parent.mkdir(parents=True, exist_ok=True)
    return target


def report_log(report: Path, *, data_dir: Path = DATA_DIR) -> Path:
    try:
        relative = report.resolve().relative_to((data_dir / "reports").resolve())
    except ValueError:
        identity = hashlib.sha256(str(report.absolute()).encode()).hexdigest()[:8]
        relative = Path("custom") / (report.stem + "-" + identity + ".json")
    target = data_dir / "logs" / relative.with_suffix(".pytest.log")
    if target.exists():
        raise FileExistsError(f"Log already exists: {target}")
    target.parent.mkdir(parents=True, exist_ok=True)
    return target


def resolve_report_input(path: Path, *, data_dir: Path = DATA_DIR) -> Path:
    if path.exists():
        return path
    mappings = {}
    for record in sorted((data_dir / "reports/migrations").glob("*.json")):
        for move in json.loads(record.read_text()).get("moves", []):
            mappings[Path(move["source"]).resolve()] = Path(move["destination"])
    visited = set()
    while not path.exists() and path.resolve() in mappings and path.resolve() not in visited:
        visited.add(path.resolve())
        path = mappings[path.resolve()]
    return path