#!/usr/bin/env python3
"""Audit a BookTTS text corpus and emit reproducible statistics and samples."""

from __future__ import annotations

import argparse
import hashlib
import json
import random
import re
import sys
from pathlib import Path


MARKUP_PATTERNS = ("{{", "}}", "[[", "]]", "<ref", "</", "{|", "|}", "http://", "https://")
RUSSIAN = re.compile(r"[А-Яа-яЁё]")
LETTERS = re.compile(r"[^\W\d_]", re.UNICODE)


def percentile(sorted_values: list[int], fraction: float) -> int:
    if not sorted_values:
        return 0
    return sorted_values[round((len(sorted_values) - 1) * fraction)]


def audit(args: argparse.Namespace) -> None:
    rng = random.Random(args.seed)
    lengths: list[int] = []
    words: list[int] = []
    samples: list[str] = []
    suspicious = {pattern: 0 for pattern in MARKUP_PATTERNS}
    low_russian_ratio = 0
    with_digits = 0
    with_dialogue_dash = 0
    digest = hashlib.sha256()
    with args.corpus.open("rb") as binary:
        for raw in binary:
            digest.update(raw)
            line = raw.decode("utf-8").rstrip("\r\n")
            index = len(lengths)
            lengths.append(len(line)); words.append(len(line.split()))
            if any(char.isdigit() for char in line):
                with_digits += 1
            if line.startswith(("—", "–", "-")):
                with_dialogue_dash += 1
            letters = LETTERS.findall(line)
            russian = RUSSIAN.findall(line)
            if letters and len(russian) / len(letters) < 0.75:
                low_russian_ratio += 1
            for pattern in MARKUP_PATTERNS:
                if pattern in line:
                    suspicious[pattern] += 1
            if len(samples) < args.samples:
                samples.append(line)
            else:
                replacement = rng.randint(0, index)
                if replacement < args.samples:
                    samples[replacement] = line
    ordered_lengths = sorted(lengths); ordered_words = sorted(words)
    report = {
        "corpus": str(args.corpus), "sha256": digest.hexdigest().upper(), "lines": len(lengths),
        "bytes": args.corpus.stat().st_size,
        "characters": {"min": min(lengths, default=0), "mean": sum(lengths) / len(lengths) if lengths else 0, "p50": percentile(ordered_lengths, 0.50), "p95": percentile(ordered_lengths, 0.95), "max": max(lengths, default=0)},
        "words": {"min": min(words, default=0), "mean": sum(words) / len(words) if words else 0, "p50": percentile(ordered_words, 0.50), "p95": percentile(ordered_words, 0.95), "max": max(words, default=0)},
        "with_digits": with_digits, "with_dialogue_dash": with_dialogue_dash,
        "below_75_percent_russian_letters": low_russian_ratio, "suspicious_markup": suspicious,
        "sample_seed": args.seed, "samples": samples,
    }
    rendered = json.dumps(report, ensure_ascii=False, indent=2) + "\n"
    if args.output:
        if args.output.exists():
            raise FileExistsError(f"Refusing to overwrite {args.output}")
        args.output.write_text(rendered, encoding="utf-8")
    print(rendered, end="")


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser()
    parser.add_argument("--corpus", type=Path, required=True)
    parser.add_argument("--output", type=Path)
    parser.add_argument("--samples", type=int, default=20)
    parser.add_argument("--seed", type=int, default=20260721)
    return parser.parse_args()


if __name__ == "__main__":
    sys.exit(audit(parse_args()) or 0)