"""`structure_mirror` task generator."""
import json
import random
import shutil
from collections import defaultdict
from pathlib import Path

from ..base import (
    Generator, _VERIFY_HEADER, _render_verify, pad_to, _write, _para,
    _AUTHORS, _SONG_TITLES, _STUDENTS, _WORDS,
)


class StructureMirror(Generator):
    KEY = "structure_mirror"
    CATEGORY_NAME = "Structure Mirror"
    DIFFICULTY = "L2"
    TAGS = ["folder structure", "organization"]

    SRC = "source"
    DST = "mirror"

    def build(self, env_dir, llm, rng):
        subdirs = ["docs", "docs/api", "src", "src/utils", "tests", "data/raw"]
        rng.shuffle(subdirs)
        subdirs = subdirs[: rng.randint(4, 6)]
        # ensure parents implied
        full = set()
        for d in subdirs:
            parts = d.split("/")
            for i in range(1, len(parts) + 1):
                full.add("/".join(parts[:i]))
        for d in sorted(full):
            (env_dir / self.SRC / d).mkdir(parents=True, exist_ok=True)
            _write(env_dir / self.SRC / d / "note.txt", "placeholder\n")
        _write(env_dir / self.SRC / "readme.txt", "root file\n")
        return {"src": self.SRC, "dst": self.DST, "dirs": sorted(full)}

    def description(self, spec):
        return (
            "Please use FileSystem tools to finish the following task:\n\n"
            "### Task: Mirror a directory structure\n\n"
            f"Create a folder `{self.DST}/` in the test directory root that "
            f"replicates the **directory structure** of `{self.SRC}/` — every "
            f"subdirectory of `{self.SRC}/` (at every depth) must exist at the same "
            f"relative path under `{self.DST}/`.\n\n"
            f"- Recreate directories only. `{self.DST}/` must contain **no files**.\n"
            f"- Do not modify `{self.SRC}/`."
        )

    def verify_src(self, spec):
        body = '''
C = json.loads(__CONSTS__)


def main():
    t = get_test_dir()
    dst = t / C["dst"]
    if not dst.is_dir():
        fail(f"missing directory: {C['dst']}")
    for d in C["dirs"]:
        if not (dst / d).is_dir():
            fail(f"missing mirrored directory: {C['dst']}/{d}")
    # No files anywhere under dst.
    for p in dst.rglob("*"):
        if p.is_file() and p.name not in SYSTEM_FILES:
            fail(f"{C['dst']} should contain no files, found: {p.relative_to(dst)}")
    ok(f"directory structure mirrored ({len(C['dirs'])} dirs, no files)")
    print("\\U0001f389 All checks passed!")
    sys.exit(0)


if __name__ == "__main__":
    main()
'''
        return _render_verify(body, {"src": spec["src"], "dst": spec["dst"], "dirs": spec["dirs"]})

    def solve(self, work_dir, spec):
        for d in spec["dirs"]:
            (work_dir / spec["dst"] / d).mkdir(parents=True, exist_ok=True)