#!/usr/bin/env python3
"""Generate word-bank.json and word-bank-ru.json with Gaussian-distributed targets.

Reads frequency-sorted word lists (most common first) from raw/ and produces
word banks with 100 Gaussian-picked targets per language.

Gaussian parameters:
  mean = 0 (index of the most frequent word)
  sigma = 100 (index 100 is at 1σ → ~68% of picks land in the first 100 words)

Target IDs are assigned in ascending index order, so ID 1 is the most common
selected word and ID 100 is the least common.
"""

import json
from pathlib import Path
import numpy as np

RAW_DIR = Path(__file__).parent
DATA_DIR = RAW_DIR.parent / "data"
SEED = 42
TARGET_COUNT = 100
SIGMA = 100

def load_dictionary(path: Path) -> list[str]:
    """Read frequency-sorted word list (one word per line). Preserves order."""
    words = [line.strip() for line in path.read_text(encoding="utf-8").splitlines() if line.strip()]
    return words

def select_target_indices(rng: np.random.Generator, dict_len: int, count: int) -> list[int]:
    """Gaussian sample indices, de-duplicating via rejection.
    Sorted ascending so ID 1 = most common word."""
    selected: set[int] = set()
    while len(selected) < count:
        samples = np.abs(np.floor(rng.normal(loc=0, scale=SIGMA, size=count * 2)))
        for s in samples:
            idx = int(s)
            if 0 <= idx < dict_len:
                selected.add(idx)
            if len(selected) >= count:
                break
    return sorted(selected)

def generate_bank(dict_path: Path, output_path: Path) -> None:
    rng = np.random.default_rng(SEED)
    guessable = load_dictionary(dict_path)
    indices = select_target_indices(rng, len(guessable), TARGET_COUNT)
    targets = [{"word": guessable[idx]} for i, idx in enumerate(indices)]

    bank = {"guessable": guessable, "targets": targets}
    output_path.write_text(
        json.dumps(bank, ensure_ascii=False, indent=2) + "\n",
        encoding="utf-8",
    )

    print(f"Wrote {output_path}: {len(guessable)} guessable, {len(targets)} targets")

    # Sanity checks
    target_words = [t["word"] for t in targets]
    assert all(w in guessable for w in target_words), "Target word not in guessable!"
    assert len(set(target_words)) == TARGET_COUNT, f"Duplicate target words ({len(set(target_words))} unique)!"
    print(f"  Top 5: {[targets[i]['word'] for i in range(5)]}")

def main():
    generate_bank(
        RAW_DIR / "english-5letter-freq-sortfreq-wordsonly.txt",
        DATA_DIR / "word-bank.json",
    )
    generate_bank(
        RAW_DIR / "russian-5letter-freq-sortfreq-wordsonly.txt",
        DATA_DIR / "word-bank-ru.json",
    )
    print("Done. Run 'npm run solve' to validate solvability.")

if __name__ == "__main__":
    main()