"""Cross-run, cross-channel record of completed URLs.

This is what prevents re-downloading your collection: state.json only knows
about one OUT_DIR, but the same gofile link posted in a second channel would
otherwise be downloaded again into that channel's OUT_DIR. The global store
(default: ~/.local/share/dlphelper/urls.json) records every successfully
downloaded URL once, forever, regardless of OUT_DIR.
"""

from __future__ import annotations

import json
import logging
import os
import time
from pathlib import Path

log = logging.getLogger(__name__)


def default_global_path() -> Path:
    data_home = os.environ.get("XDG_DATA_HOME") or str(
        Path.home() / ".local" / "share"
    )
    return Path(data_home) / "dlphelper" / "urls.json"


class GlobalStore:
    """JSON file mapping url -> {status, channel, host, files, updated}."""

    def __init__(self, path: Path | None = None):
        self.path = path
        self.records: dict[str, dict] = {}
        if self.path and self.path.exists():
            try:
                self.records = json.loads(self.path.read_text(encoding="utf-8"))
                if not isinstance(self.records, dict):
                    raise ValueError("global store root must be an object")
            except (ValueError, OSError) as exc:
                backup = self.path.with_suffix(".json.bak")
                log.warning("Corrupt global store %s (%s); backed up to %s",
                            self.path, exc, backup)
                self.path.replace(backup)
                self.records = {}

    def is_done(self, url: str) -> bool:
        if not self.records:
            return False
        rec = self.records.get(url)
        return bool(rec) and rec.get("status") == "ok"

    def mark(self, url: str, **fields) -> None:
        if self.path is None:
            return
        rec = self.records.setdefault(url, {"status": "ok"})
        for key, value in fields.items():
            if value is not None:
                rec[key] = value
        rec["status"] = "ok"
        rec["updated"] = time.strftime("%Y-%m-%dT%H:%M:%S")
        self.save()

    def save(self) -> None:
        if self.path is None:
            return
        self.path.parent.mkdir(parents=True, exist_ok=True)
        tmp = self.path.with_suffix(".json.tmp")
        tmp.write_text(json.dumps(self.records, indent=2, sort_keys=True),
                       encoding="utf-8")
        tmp.replace(self.path)