from __future__ import annotations

import json
from dataclasses import dataclass
from typing import Any

from huggingface_hub import HfFileSystem

from .config import settings
from .security import redact


@dataclass(frozen=True)
class RunPaths:
    run_id: str
    bucket_uri: str = settings.bucket_uri

    @property
    def root(self) -> str:
        return f"{self.bucket_uri}/runs/{self.run_id}"

    @property
    def state(self) -> str:
        return f"{self.root}/state.json"

    @property
    def events(self) -> str:
        return f"{self.root}/events.jsonl"

    @property
    def report(self) -> str:
        return f"{self.root}/report.md"


def _fs(token: str | None = None) -> HfFileSystem:
    return HfFileSystem(token=token)


def read_text(path: str, token: str | None = None) -> str | None:
    fs = _fs(token)
    try:
        with fs.open(path, "r") as f:
            return f.read()
    except FileNotFoundError:
        return None
    except Exception as exc:  # noqa: BLE001 - surface readable error in UI
        return f"[Could not read {path}: {exc}]"


def read_json(path: str, token: str | None = None) -> dict[str, Any] | None:
    content = read_text(path, token=token)
    if not content or content.startswith("[Could not read"):
        return None
    try:
        return json.loads(content)
    except json.JSONDecodeError:
        return {"_error": "Invalid JSON", "raw": redact(content)}


def read_events(run_id: str, token: str | None = None) -> list[dict[str, Any]]:
    paths = RunPaths(run_id)
    content = read_text(paths.events, token=token)
    if not content:
        return []
    events: list[dict[str, Any]] = []
    for line in content.splitlines():
        line = line.strip()
        if not line:
            continue
        try:
            events.append(json.loads(line))
        except json.JSONDecodeError:
            events.append({"step": "parse_events", "status": "warning", "message": redact(line)})
    return events


def read_run_bundle(run_id: str, token: str | None = None) -> dict[str, Any]:
    paths = RunPaths(run_id)
    return {
        "paths": {
            "root": paths.root,
            "state": paths.state,
            "events": paths.events,
            "report": paths.report,
        },
        "state": read_json(paths.state, token=token),
        "events": read_events(run_id, token=token),
        "report": redact(read_text(paths.report, token=token) or ""),
    }