#!/usr/bin/env python3
"""
Kabyle-letter checker – Hugging Face Space edition
Run locally:  python app.py
On Spaces the container starts this file automatically.
"""

import io, re, unicodedata, uuid
from collections import Counter
from pathlib import Path

from flask import (Flask, render_template_string, request, send_file,
                   url_for, flash, redirect)
from tqdm import tqdm

# ------------------------------------------------------------------ constants
ALLOWED = set(
    "a b c d e f g h i j k l m n o p q r s t u v w x y z "
    "č ḍ ǧ ḥ ɣ ṛ ṣ ṭ ɛ ẓ".split()
)
UPLOAD_DIR = Path("uploads")
CSV_DIR    = Path("csv")
UPLOAD_DIR.mkdir(exist_ok=True)
CSV_DIR.mkdir(exist_ok=True)

PER_PAGE = 50   # sentences per page for pagination

# ------------------------------------------------------------------ Flask app
app = Flask(__name__)
app.secret_key = uuid.uuid4().hex       # random on every restart

# ------------------------------------------------------------------ helpers
def _is_ok(ch):  # quick reusable test
    return ch.isalpha() and (ch.lower() in ALLOWED)

def analyse(path: Path):
    """
    Returns:
        counter   – Counter of illegal chars
        sentences – list[dict] with keys
                     line_nr, sentence, bad_chars (set), highlights (HTML)
    """
    counter, sentences = Counter(), []
    with path.open(encoding="utf-8") as fh:
        for line_nr, sentence in enumerate(tqdm(fh, unit=" lines", desc="Analysing"), 1):
            bad = {ch for ch in sentence if not _is_ok(ch) if ch.isalpha()}
            if bad:
                # build red-span version
                highlighted = re.sub(
                    r"([^\s])",
                    lambda m: (f'<span style="color:red">{m.group(0)}</span>'
                               if not _is_ok(m.group(0)) and m.group(0).isalpha()
                               else m.group(0)),
                    sentence,
                )
                sentences.append({
                    "line_nr": line_nr,
                    "sentence": sentence.rstrip(),
                    "bad_chars": bad,
                    "highlights": highlighted.rstrip(),
                })
                for ch in bad:
                    counter[ch] += 1
    return counter, sentences

# ------------------------------------------------------------------ routes
@app.route("/", methods=["GET", "POST"])
def index():
    if request.method == "POST":
        file = request.files.get("file")
        if not file or file.filename == "":
            flash("No file selected")
            return redirect(request.url)

        uid   = uuid.uuid4().hex
        fpath = UPLOAD_DIR / f"{uid}.txt"
        file.save(fpath)

        counter, sentences = analyse(fpath)

        # CSV
        csv_io = io.StringIO()
        csv_io.write("char,codepoint,count,unicode_name\n")
        for ch, freq in counter.most_common():
            csv_io.write(f"{ch},U+{ord(ch):04X},{freq},{unicodedata.name(ch,'')}\n")
        (CSV_DIR / f"{uid}.csv").write_text(csv_io.getvalue(), encoding="utf-8")

        # store sentences list for /show/<uid>
        (CSV_DIR / f"{uid}_sentences.txt").write_text(
            "\n".join(f'{s["line_nr"]:>6}  {s["sentence"]}' for s in sentences),
            encoding="utf-8",
        )

        table_rows = [
            {"char": ch, "code": f"U+{ord(ch):04X}", "count": freq,
             "name": unicodedata.name(ch, "")}
            for ch, freq in counter.most_common()
        ]
        total_lines = sum(1 for _ in fpath.open(encoding="utf-8"))
        return render_template_string(
            TEMPLATE_RESULT,
            table=table_rows,
            total_lines=total_lines,
            csv_url=url_for("download", uid=uid),
            show_url=url_for("show_sentences", uid=uid),
            sent_count=len(sentences),
        )
    return render_template_string(TEMPLATE_INDEX)

@app.route("/csv/<uid>")
def download(uid):
    return send_file(CSV_DIR / f"{uid}.csv", as_attachment=True,
                     download_name="unsupported_stats.csv")

@app.route("/show/<uid>")
def show_sentences(uid):
    """Display affected sentences with red highlights (paginated)."""
    # recover all sentences from disk
    all_sentences = []
    for raw in (CSV_DIR / f"{uid}_sentences.txt").read_text(encoding="utf-8").splitlines():
        line_nr, sentence = raw[:6].strip(), raw[8:]
        bad = {ch for ch in sentence if not _is_ok(ch) if ch.isalpha()}
        highlighted = re.sub(
            r"([^\s])",
            lambda m: (f'<span style="color:red;font-weight:bold">{m.group(0)}</span>'
                       if not _is_ok(m.group(0)) and m.group(0).isalpha()
                       else m.group(0)),
            sentence,
        )
        all_sentences.append({
            "line_nr": line_nr,
            "highlights": highlighted,
            "sentence": sentence,
        })

    # ----- pagination logic -----
    page = request.args.get('page', 1, type=int)
    if page < 1:
        page = 1

    total = len(all_sentences)
    total_pages = (total + PER_PAGE - 1) // PER_PAGE if total else 1
    if page > total_pages:
        page = total_pages

    start = (page - 1) * PER_PAGE
    end = start + PER_PAGE
    sentences = all_sentences[start:end]

    prev_url = url_for('show_sentences', uid=uid, page=page-1) if page > 1 else None
    next_url = url_for('show_sentences', uid=uid, page=page+1) if page < total_pages else None
    # ---------------------------

    return render_template_string(
        TEMPLATE_SHOW,
        sentences=sentences,
        back_url=url_for("index"),
        page=page,
        total_pages=total_pages,
        prev_url=prev_url,
        next_url=next_url,
        total=total,
    )

# ------------------------------------------------------------------ templates
TEMPLATE_INDEX = """
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Tatoeba Kabyle Corpus Standardisation Checker</title>
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body class="bg-light">
<div class="container py-5">
  <h1 class="mb-3">Tatoeba Kabyle Corpus Standardisation Checker</h1>
  <p class="lead mb-4">Upload Kabyle sentences from Tatoeba and spot letters/symbols that are <strong>not</strong> part of the official Kabyle alphabet (CLDR). Download a CSV or view highlighted sentences ready for correction.</p>

  <form method="post" enctype="multipart/form-data" class="mb-4">
    <div class="input-group">
      <input type="file" name="file" class="form-control" required>
      <button class="btn btn-primary" type="submit">Upload & analyse</button>
    </div>
  </form>

  {% with msgs = get_flashed_messages() %}
    {% if msgs %}<<div class="alert alert-warning">{{ msgs[0] }}</div>{% endif %}
  {% endwith %}
</div>
</body>
</html>
"""

TEMPLATE_RESULT = """
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Tatoeba Kabyle Corpus Standardisation Checker</title>
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body class="bg-light">
<div class="container py-5">
  <h1 class="mb-3">Tatoeba Kabyle Corpus Standardisation Checker</h1>

  <div class="alert alert-info">Analysed {{ total_lines }} lines.
   Found {{ sent_count }} sentence(s) with non-standard letters.</div>

  <h2>Result table</h2>
  <div class="table-responsive">
    <table class="table table-sm table-striped align-middle">
      <thead class="table-light">
        <tr><th>Char</th><th>Codepoint</th><th>Count</th><th>Unicode name</th></tr>
      </thead>
      <tbody>
      {% for row in table %}
        <tr>
          <td style="font-size:1.5rem">{{ row.char }}</td>
          <td><code>{{ row.code }}</code></td>
          <td>{{ row.count }}</td>
          <td><small>{{ row.name }}</small></td>
        </tr>
      {% endfor %}
      </tbody>
    </table>
  </div>

  <a class="btn btn-outline-success" href="{{ csv_url }}">⬇ Download CSV</a>
  <a class="btn btn-outline-primary ms-2" href="{{ show_url }}">👁 Show affected sentences</a>
</div>
</body>
</html>
"""

TEMPLATE_SHOW = """
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Tatoeba Kabyle Corpus Standardisation Checker</title>
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body class="bg-light">
<div class="container py-5">
  <h1 class="mb-3">Tatoeba Kabyle Corpus Standardisation Checker</h1>
  <a class="btn btn-outline-secondary mb-3" href="{{ back_url }}">← Back</a>

  <p class="text-muted">Showing {{ sentences|length }} of {{ total }} affected sentences — Page {{ page }} of {{ total_pages }}</p>

  <ol start="{{ (page - 1) * 50 + 1 }}">
  {% for s in sentences %}
    <li class="mb-2">
      <pre style="display:inline; margin:0; padding:0; border:none; background:none;">{{ s.highlights|safe }}</pre>
      <small class="text-muted">(line {{ s.line_nr }})</small>
      <a class="btn btn-sm btn-outline-primary ms-2"
         href="https://tatoeba.org/en/sentences/search?from=kab&query={{ s.sentence|urlencode }}&to="
         target="_blank" title="Search on Tatoeba" aria-label="Search">🔍</a>
    </li>
  {% endfor %}
  </ol>

  <!-- Pagination -->
  <nav aria-label="Sentence pages" class="mt-4">
    <ul class="pagination justify-content-center">
      <li class="page-item {% if not prev_url %}disabled{% endif %}">
        <a class="page-link" href="{{ prev_url or '#' }}">← Previous</a>
      </li>
      <li class="page-item disabled">
        <span class="page-link">Page {{ page }} of {{ total_pages }}</span>
      </li>
      <li class="page-item {% if not next_url %}disabled{% endif %}">
        <a class="page-link" href="{{ next_url or '#' }}">Next →</a>
      </li>
    </ul>
  </nav>
</div>
</body>
</html>
"""

# ------------------------------------------------------------------ entrypoint
if __name__ == "__main__":
    # 0.0.0.0:7860 is mandatory for Hugging Face Spaces
    app.run(host="0.0.0.0", port=7860, debug=False)