"""Admin-Panel (Flask): Schema-Designer, Dropzone, Linkliste, Versionen.

In Produktion liegt das Panel hinter Nginx Basic Auth; die
oeffentlichen Seiten liefert Nginx direkt aus public/ aus.
"""
from __future__ import annotations

import io
import os

from flask import (
    Flask,
    abort,
    flash,
    redirect,
    render_template,
    request,
    send_file,
    url_for,
)

from . import engine, storage

app = Flask(__name__)
# Secret nur fuer Flash-Messages; bei Neustart verfallende Session ist ok.
app.secret_key = os.environ.get("QT_SECRET_KEY") or os.urandom(16)


@app.get("/")
def root():
    return redirect(url_for("admin_index"))


@app.get("/admin/")
def admin_index():
    return render_template(
        "admin/index.html",
        tables=storage.list_tables(),
        qr_svg=engine.qr_svg,
    )


@app.route("/admin/neu", methods=["GET", "POST"])
def admin_new():
    if request.method == "GET":
        return render_template("admin/new.html", types=engine.TYPE_LABELS)

    title = request.form.get("title", "").strip()
    labels = [l.strip() for l in request.form.getlist("label")]
    types = request.form.getlist("type")

    columns = []
    seen_keys = set()
    for label, ctype in zip(labels, types):
        if not label:
            continue
        if ctype not in engine.COLUMN_TYPES:
            ctype = "text"
        key = engine.column_key(label)
        while key in seen_keys:
            key += "_2"
        seen_keys.add(key)
        columns.append({"key": key, "label": label, "type": ctype})

    error = None
    if not title:
        error = "Bitte einen Titel angeben."
    elif not columns:
        error = "Mindestens eine Spalte anlegen."
    else:
        slug = engine.slugify(title)
        if storage.load_schema(slug) is not None:
            error = f'Es gibt schon eine Tabelle mit dem Slug "{slug}".'

    if error:
        flash(error, "error")
        return render_template(
            "admin/new.html",
            types=engine.TYPE_LABELS,
            title=title,
            columns=columns,
        )

    storage.save_schema({"slug": slug, "title": title, "columns": columns})
    flash(f'Tabelle "{title}" angelegt. Jetzt die CSV-Vorlage herunterladen.', "ok")
    return redirect(url_for("admin_index"))


@app.get("/admin/vorlage/<slug>")
def admin_template(slug):
    schema = storage.load_schema(slug)
    if schema is None:
        abort(404)
    return send_file(
        io.BytesIO(engine.template_csv(schema)),
        mimetype="text/csv",
        as_attachment=True,
        download_name=f"{slug}.csv",
    )


@app.post("/admin/upload")
def admin_upload():
    file = request.files.get("csv")
    if file is None or not file.filename:
        flash("Keine Datei ausgewaehlt.", "error")
        return redirect(url_for("admin_index"))

    raw = file.read()
    header, _ = engine.parse_csv(raw)

    slug = request.form.get("slug", "").strip()
    if not slug:  # automatisch erkennen
        slug = storage.find_table(file.filename, header)
    if not slug:
        flash(
            "Tabelle nicht erkannt — bitte im Auswahlfeld die Zieltabelle "
            "waehlen und erneut hochladen.",
            "error",
        )
        return redirect(url_for("admin_index"))

    ok, errors, warnings, version = storage.publish_upload(slug, raw)
    for w in warnings:
        flash(w, "warn")
    if not ok:
        for e in errors[:10]:
            flash(e, "error")
        if len(errors) > 10:
            flash(f"... und {len(errors) - 10} weitere Fehler.", "error")
        flash("Nichts veroeffentlicht — bitte CSV korrigieren und erneut hochladen.", "error")
    else:
        flash(
            f'"{slug}" aktualisiert (Version {version}) und veroeffentlicht: '
            f"{storage.public_url(slug)}",
            "ok",
        )
    return redirect(url_for("admin_index"))


@app.get("/admin/csv/<slug>/<filename>")
def admin_download(slug, filename):
    raw = storage.read_version(slug, filename)
    if raw is None:
        abort(404)
    return send_file(
        io.BytesIO(raw),
        mimetype="text/csv",
        as_attachment=True,
        download_name=f"{slug}_{filename}",
    )


@app.post("/admin/loeschen/<slug>")
def admin_delete(slug):
    if storage.load_schema(slug) is None:
        abort(404)
    storage.delete_table(slug)
    flash(f'Tabelle "{slug}" samt Versionen geloescht.', "ok")
    return redirect(url_for("admin_index"))


@app.get("/<slug>/")
def public_page(slug):
    """Nur fuer die lokale Entwicklung — in Produktion macht das Nginx."""
    path = storage.PUBLIC_DIR / slug / "index.html"
    if not path.exists():
        abort(404)
    return send_file(path.resolve())


if __name__ == "__main__":
    app.run(debug=True)