"""Task-type generators for synthetic filesystem benchmarks.

Each generator produces a self-consistent task:

* ``build(env_dir, llm, rng)`` writes the initial files into the test
  environment and returns a ``spec`` dict describing what it created.
* ``description(spec)`` renders the natural-language ``description.md`` the model
  will see.
* ``verify_src(spec)`` renders a self-contained ``verify.py`` whose checks
  *recompute* the correct answer from the resulting files (no external answer
  key), using only the standard library.
* ``solve(work_dir, spec)`` is the oracle: it performs the correct solution
  in-place so the pipeline can prove ``verify.py`` accepts the intended answer.

The description and the verifier are written together so they always agree.
"""

import json
import random
import shutil
from collections import defaultdict
from pathlib import Path
from typing import Dict, List

# --------------------------------------------------------------------------- #
# Shared helpers
# --------------------------------------------------------------------------- #

_FILLER = " lorem ipsum dolor sit amet consectetur adipiscing elit"


def _ascii_filler(n: int) -> str:
    if n <= 0:
        return ""
    return (_FILLER * (n // len(_FILLER) + 1))[:n]


def pad_to(body: str, target_bytes: int) -> str:
    """Return text whose UTF-8 size is exactly ``target_bytes``."""
    b = body.encode("utf-8")
    if len(b) > target_bytes:
        return b[:target_bytes].decode("utf-8", errors="ignore")
    return body + _ascii_filler(target_bytes - len(b.decode("utf-8").encode("utf-8")))


def _write(path: Path, content: str) -> None:
    path.parent.mkdir(parents=True, exist_ok=True)
    path.write_text(content, encoding="utf-8")


# Header shared by every generated verify.py.
_VERIFY_HEADER = '''#!/usr/bin/env python3
"""Auto-generated verifier (synthetic task). Recomputes the answer; do not edit."""
import json
import os
import sys
from pathlib import Path

SYSTEM_FILES = {".DS_Store", "Thumbs.db", ".DS_Store?", "._.DS_Store"}


def get_test_dir() -> Path:
    d = os.environ.get("FILESYSTEM_TEST_DIR")
    if not d:
        raise ValueError("FILESYSTEM_TEST_DIR environment variable is required")
    return Path(d)


def fail(msg):
    print("\\u274c " + msg)
    sys.exit(1)


def ok(msg):
    print("\\u2705 " + msg)
'''


class Generator:
    KEY = "base"
    CATEGORY_NAME = "Base"
    DIFFICULTY = "L2"
    TAGS: List[str] = []

    def __init__(self, difficulty: str = "medium"):
        # Generators that support difficulty tiers read self.difficulty; the rest
        # simply ignore it.
        self.difficulty = difficulty

    def build(self, env_dir: Path, llm, rng: random.Random) -> Dict:
        raise NotImplementedError

    def description(self, spec: Dict) -> str:
        raise NotImplementedError

    def verify_src(self, spec: Dict) -> str:
        raise NotImplementedError

    def solve(self, work_dir: Path, spec: Dict) -> None:
        raise NotImplementedError


def _render_verify(body: str, consts: dict) -> str:
    return _VERIFY_HEADER + body.replace("__CONSTS__", json.dumps(json.dumps(consts)))


_AUTHORS = ["Ada Lovelace", "Alan Turing", "Grace Hopper", "Donald Knuth", "Barbara Liskov"]
_SONG_TITLES = [
    "Blue Horizon", "Midnight Drive", "Paper Moon", "Echoes", "Golden Hour",
    "Silent Tide", "Neon Rain", "Wandering", "Afterglow", "Velvet Sky",
    "Lighthouse", "Crossroads",
]
_STUDENTS = [
    "Liam Carter", "Olivia Reed", "Noah Patel", "Emma Davies", "Mason Cole",
    "Ava Brooks", "Lucas Gray", "Mia Foster", "Ethan Ward", "Sofia Bennett",
]
_WORDS = (
    "system module config network buffer kernel thread cache socket render "
    "matrix tensor sample dataset gradient logging parser schema invoice client"
).split()


def _para(rng: random.Random, n_lines: int, inject=None) -> list:
    lines = []
    for _ in range(n_lines):
        line = " ".join(rng.choice(_WORDS) for _ in range(rng.randint(4, 9))).capitalize() + "."
        lines.append(line)
    if inject:
        # inject is a list of (index, text); replace those lines
        for idx, text in inject:
            lines[idx % len(lines)] = text
    return lines