#!/usr/bin/env python3
from __future__ import annotations

import json
import os
from pathlib import Path
from typing import Any


def read_jsonl(path: str | Path) -> list[dict[str, Any]]:
    with Path(path).open("r", encoding="utf-8") as f:
        return [json.loads(line) for line in f if line.strip()]


def resolve_data_paths(row: dict[str, Any], data_root: str | Path | None = None) -> dict[str, Any]:
    """Return a copy of a row with image/mask-like paths resolved locally.

    By default, `data_root` is read from FAME_DATA_ROOT. The episode loaders
    pass the release root when `resolve_paths=True`, so bundled data paths work
    without extra configuration.
    """
    root_value = str(data_root or os.environ.get("FAME_DATA_ROOT", "")).strip()
    if not root_value:
        return dict(row)
    root = Path(root_value)
    out = dict(row)
    for key in ["image", "mask"]:
        value = out.get(key)
        if isinstance(value, str) and value and not value.startswith("/") and "::" not in value:
            out[key] = str(root / value)
    return out


def load_episode(
    release_root: str | Path,
    task: str,
    seed: int = 0,
    k: int = 10,
    resolve_paths: bool = False,
    data_root: str | Path | None = None,
) -> tuple[list[dict[str, Any]], list[dict[str, Any]]]:
    root = Path(release_root)
    ep_dir = root / "FAME_benchmark" / "episodes" / f"k{k}_seed{seed}" / task
    support = read_jsonl(ep_dir / "support.jsonl")
    query = read_jsonl(ep_dir / "test.jsonl")
    if resolve_paths:
        local_root = Path(data_root) if data_root is not None else root
        support = [resolve_data_paths(row, data_root=local_root) for row in support]
        query = [resolve_data_paths(row, data_root=local_root) for row in query]
    return support, query


def load_ood_episode(
    release_root: str | Path,
    pair_id: str,
    setting: str = "k10_seed0",
    resolve_paths: bool = False,
    data_root: str | Path | None = None,
) -> tuple[list[dict[str, Any]], list[dict[str, Any]], dict[str, Any]]:
    root = Path(release_root)
    ep_dir = root / "FAME_benchmark" / "ood_episodes" / setting / pair_id
    support = read_jsonl(ep_dir / "support.jsonl")
    query = read_jsonl(ep_dir / "test.jsonl")
    info = json.loads((ep_dir / "ood_pair_info.json").read_text(encoding="utf-8"))
    if resolve_paths:
        local_root = Path(data_root) if data_root is not None else root
        support = [resolve_data_paths(row, data_root=local_root) for row in support]
        query = [resolve_data_paths(row, data_root=local_root) for row in query]
    return support, query, info


def list_tasks(release_root: str | Path) -> list[str]:
    path = Path(release_root) / "FAME_benchmark" / "task_lists" / "FAME_benchmark_tasks.txt"
    return [line.strip() for line in path.read_text(encoding="utf-8").splitlines() if line.strip()]


def list_ood_pairs(release_root: str | Path) -> list[str]:
    path = Path(release_root) / "FAME_benchmark" / "task_lists" / "FAME_ood_pairs_all.txt"
    if path.exists():
        return [line.strip() for line in path.read_text(encoding="utf-8").splitlines() if line.strip()]
    root = Path(release_root) / "FAME_benchmark" / "ood_episodes" / "k10_seed0"
    return sorted(p.name for p in root.iterdir() if p.is_dir()) if root.exists() else []