from __future__ import annotations

import json
from dataclasses import dataclass
from typing import Any

from huggingface_hub import HfFileSystem, bucket_info, create_bucket

from .config import bucket_uri_from_source, normalize_bucket_name, settings, user_bucket_source
from .security import redact


@dataclass(frozen=True)
class RunPaths:
    run_id: str
    bucket_source: str

    @property
    def bucket_uri(self) -> str:
        return bucket_uri_from_source(self.bucket_source)

    @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 check_user_bucket(*, username: str, bucket_name: str | None = None, token: str | None = None) -> dict[str, Any]:
    """Return bucket readiness for the signed-in user without creating resources."""
    bucket_source = user_bucket_source(username=username, bucket_name=bucket_name)
    bucket_uri = bucket_uri_from_source(bucket_source)
    try:
        info = bucket_info(bucket_source, token=token)
        return {
            "ok": True,
            "exists": True,
            "bucket_source": bucket_source,
            "bucket_uri": bucket_uri,
            "name": getattr(info, "name", normalize_bucket_name(bucket_name)),
            "private": getattr(info, "private", None),
        }
    except Exception as exc:  # noqa: BLE001 - report readable status in UI
        error = str(exc)
        not_found = any(marker in error.lower() for marker in ["404", "not found", "repository not found", "bucket not found"])
        return {
            "ok": False,
            "exists": False if not_found else None,
            "bucket_source": bucket_source,
            "bucket_uri": bucket_uri,
            "error": error,
        }


def create_user_bucket(*, username: str, bucket_name: str | None = None, token: str | None = None) -> dict[str, Any]:
    """Create the signed-in user's private run bucket, then return readiness."""
    bucket_source = user_bucket_source(username=username, bucket_name=bucket_name)
    try:
        url = create_bucket(bucket_source, private=True, exist_ok=True, token=token)
    except Exception as exc:  # noqa: BLE001
        return {
            "ok": False,
            "exists": None,
            "bucket_source": bucket_source,
            "bucket_uri": bucket_uri_from_source(bucket_source),
            "error": str(exc),
        }
    status = check_user_bucket(username=username, bucket_name=bucket_name, token=token)
    status["created_or_existing"] = True
    status["create_url"] = str(url)
    return status


def assert_user_bucket_ready(*, username: str, bucket_name: str | None = None, token: str | None = None) -> dict[str, Any]:
    """Raise a clear error if the user's run bucket cannot be used."""
    status = check_user_bucket(username=username, bucket_name=bucket_name, token=token)
    if not status.get("ok"):
        source = status.get("bucket_source") or user_bucket_source(username=username, bucket_name=bucket_name)
        error = status.get("error") or "Bucket does not exist or is not accessible."
        raise ValueError(
            f"Run bucket `{source}` is not ready. Click 'Create private run bucket' first, "
            f"or create it manually in Hugging Face Storage Buckets. Details: {error}"
        )
    return status


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, *, bucket_source: str, token: str | None = None) -> list[dict[str, Any]]:
    paths = RunPaths(run_id, bucket_source=bucket_source)
    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, *, bucket_source: str, token: str | None = None) -> dict[str, Any]:
    paths = RunPaths(run_id, bucket_source=bucket_source)
    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, bucket_source=bucket_source, token=token),
        "report": redact(read_text(paths.report, token=token) or ""),
    }