import logging
import os
import re
import threading
import time
from collections import defaultdict
from datetime import date, datetime, timedelta
from logging.handlers import RotatingFileHandler

import bleach
from bleach.css_sanitizer import CSSSanitizer
from flask import (
    Flask, flash, jsonify, redirect, render_template, request, url_for,
)
from flask_sqlalchemy import SQLAlchemy
from flask_wtf import CSRFProtect
from markupsafe import Markup
from werkzeug.middleware.proxy_fix import ProxyFix

from config import Config
from mailer import send_email_async

db = SQLAlchemy()
csrf = CSRFProtect()


class Section(db.Model):
    __tablename__ = "section"
    id = db.Column(db.Integer, primary_key=True)
    num = db.Column(db.Integer, nullable=False, unique=True)
    title = db.Column(db.String(160), nullable=False)
    subtitle = db.Column(db.String(255))
    sort_order = db.Column(db.Integer, nullable=False, default=0)
    topics = db.relationship(
        "Topic",
        backref="section",
        order_by="Topic.sort_order",
        cascade="all, delete-orphan",
    )

    @property
    def published_topics(self):
        # Topics are already ordered by sort_order via the relationship.
        return [t for t in self.topics if t.is_published]


class Topic(db.Model):
    __tablename__ = "topic"
    id = db.Column(db.Integer, primary_key=True)
    section_id = db.Column(
        db.Integer, db.ForeignKey("section.id", ondelete="CASCADE"), nullable=False
    )
    slug = db.Column(db.String(80), nullable=False, unique=True)
    title = db.Column(db.String(200), nullable=False)
    body_html = db.Column(db.Text)
    link_url = db.Column(db.String(500))
    link_label = db.Column(db.String(120))
    media_type = db.Column(db.String(16), nullable=False, default="none")
    media_url = db.Column(db.String(500))
    media_caption = db.Column(db.String(255))
    sort_order = db.Column(db.Integer, nullable=False, default=0)
    is_published = db.Column(db.Boolean, nullable=False, default=True)

    @property
    def body(self):
        # Content is admin-authored and trusted; render as-is.
        return Markup(self.body_html or "")

    @property
    def is_youtube(self):
        u = (self.media_url or "").lower()
        return "youtube.com" in u or "youtu.be" in u


class DemoRequest(db.Model):
    """A demo appointment requested from the public page. `preferred_date` /
    `preferred_time` are what the customer picked (no timezone conversion —
    they're read back as the site's advertised local business hours)."""
    __tablename__ = "demo_request"
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(120), nullable=False)
    company = db.Column(db.String(160))
    email = db.Column(db.String(200), nullable=False)
    phone = db.Column(db.String(40))
    preferred_date = db.Column(db.Date, nullable=False)
    preferred_time = db.Column(db.String(5), nullable=False)   # 'HH:MM'
    message = db.Column(db.Text)
    status = db.Column(db.String(16), nullable=False, default="new")
    source_ip = db.Column(db.String(45))
    created_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)

    @property
    def when(self):
        return f"{self.preferred_date:%a %b %d, %Y} at {self.preferred_time}"


DEMO_STATUSES = ("new", "scheduled", "done", "cancelled")


class AuditLog(db.Model):
    __tablename__ = "audit_log"
    id = db.Column(db.Integer, primary_key=True)
    actor = db.Column(db.String(80))
    action = db.Column(db.String(40), nullable=False)      # create / update / delete
    entity = db.Column(db.String(40), nullable=False)      # section / topic
    entity_id = db.Column(db.Integer)
    detail = db.Column(db.String(255))
    created_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)


def log_action(actor, action, entity, entity_id=None, detail=None):
    """Record an audit row. MUST be called AFTER db.session.commit() of the
    change it describes, so a failed transaction never leaves an orphan log."""
    entry = AuditLog(
        actor=actor, action=action, entity=entity,
        entity_id=entity_id, detail=detail,
    )
    db.session.add(entry)
    db.session.commit()


# Tags/attributes the rich-text editor (Quill) can emit. Everything else is
# stripped on save so a WYSIWYG paste can't inject markup into the public page.
ALLOWED_TAGS = [
    "p", "br", "strong", "b", "em", "i", "u", "s", "strike",
    "ul", "ol", "li", "a", "h2", "h3", "blockquote",
    # images (inserted via the /admin/upload endpoint or a URL)
    "img",
    # tables (quill-table-better: resizable cols, aligned/styled cells)
    "table", "thead", "tbody", "tr", "td", "th", "col", "colgroup",
]
# quill-table-better carries column widths, borders and background as inline
# `style`, plus data-* bookkeeping attributes. Cell alignment is Quill's
# `ql-align-*` CSS class on the cell's <p> block, and quill-table-better also
# tags blots with `ql-table-block`/`table-th-block` classes — all of which must
# survive so the table (and its alignment) round-trips back into the editor.
_TABLE_CELL_ATTRS = [
    "data-row", "data-cell", "data-class", "colspan", "rowspan",
    "width", "height", "style", "class",
]
ALLOWED_ATTRS = {
    "a": ["href", "title", "target", "rel"],
    "img": ["src", "alt", "width", "height"],
    "p": ["style", "class", "data-cell", "data-row"],
    "table": ["class", "style", "align", "width", "height", "data-class"],
    "colgroup": ["style", "class"],
    "col": ["width", "span", "style", "class"],
    "tr": ["data-row", "style", "class"],
    "td": _TABLE_CELL_ATTRS,
    "th": _TABLE_CELL_ATTRS,
}
# Only these CSS properties survive on a `style` attribute — enough for the
# table editor's sizing/alignment/borders, nothing that can smuggle script.
ALLOWED_CSS_PROPS = [
    "width", "height", "min-width", "padding", "text-align", "vertical-align",
    "background-color", "border", "border-style", "border-color",
    "border-width", "border-collapse",
]
_css_sanitizer = CSSSanitizer(allowed_css_properties=ALLOWED_CSS_PROPS)


def sanitize_html(raw):
    """Clean editor HTML against the allowlist. Returns None for empty content
    so blank bodies stay NULL. bleach also restricts URL protocols to
    http/https/mailto for both links and images, blocking javascript: and
    data: URLs (uploaded images are served from a relative /static path). Inline
    `style` is filtered to the ALLOWED_CSS_PROPS allowlist via CSSSanitizer."""
    if not raw:
        return None
    cleaned = bleach.clean(
        raw, tags=ALLOWED_TAGS, attributes=ALLOWED_ATTRS, strip=True,
        css_sanitizer=_css_sanitizer,
    ).strip()
    # Quill leaves an empty paragraph for a blank editor.
    if cleaned in ("", "<p></p>", "<p><br></p>"):
        return None
    return cleaned


# ---------------------------------------------------------------- demo form
# Loose sanity check only — the real proof an address works is the confirmation
# mail the customer receives. Rejecting exotic-but-valid addresses is worse than
# accepting a typo the owner can see and follow up on.
EMAIL_RE = re.compile(r"^[^@\s]+@[^@\s.]+(\.[^@\s.]+)+$")

# In-memory per-IP throttle. Per gunicorn worker (not shared), which is fine:
# it exists to stop a bored visitor spamming the form, not a distributed flood.
# nginx limit_req is the right tool if that ever matters.
_demo_hits = defaultdict(list)
_demo_hits_lock = threading.Lock()


def demo_slots(config):
    """Bookable clock times as 'HH:MM', e.g. 08:00, 08:30, ... 16:30."""
    start = max(0, min(23, config.get("DEMO_HOUR_START", 8)))
    end = max(start + 1, min(24, config.get("DEMO_HOUR_END", 17)))
    step = max(5, config.get("DEMO_SLOT_MINUTES", 30))
    slots, minute = [], start * 60
    while minute < end * 60:
        slots.append(f"{minute // 60:02d}:{minute % 60:02d}")
        minute += step
    return slots


def taken_slots(day):
    """Times already booked on `day`. Cancelled requests free their slot."""
    rows = (
        DemoRequest.query
        .with_entities(DemoRequest.preferred_time)
        .filter(DemoRequest.preferred_date == day,
                DemoRequest.status != "cancelled")
        .all()
    )
    return {row[0] for row in rows}


def available_slots(config, day):
    """Bookable times left on `day` — the full grid minus what's taken."""
    if day is None:
        return demo_slots(config)
    booked = taken_slots(day)
    return [slot for slot in demo_slots(config) if slot not in booked]


def demo_day_status(config, day):
    """Why a date can't be booked, or None if it's open. Shared by the form and
    the /demo/slots endpoint so both give the same answer."""
    today = date.today()
    if day < today:
        return "That date has already passed."
    if day > today + timedelta(days=config["DEMO_MAX_DAYS_AHEAD"]):
        return (f"Please pick a date within the next "
                f"{config['DEMO_MAX_DAYS_AHEAD']} days.")
    if day.weekday() >= 5:
        return "Demonstrations run Monday through Friday."
    return None


def _rate_limited(ip, limit):
    """True if `ip` has already submitted `limit` requests in the last hour."""
    if limit <= 0:
        return False
    now = time.time()
    with _demo_hits_lock:
        hits = [t for t in _demo_hits[ip] if now - t < 3600]
        if len(hits) >= limit:
            _demo_hits[ip] = hits
            return True
        hits.append(now)
        _demo_hits[ip] = hits
    return False


def _notify_demo(app, req):
    """Mail the owner about a new appointment, and (optionally) confirm to the
    customer. Both are fire-and-forget: the row is already committed."""
    cfg = app.config
    admin_link = request.url_root.rstrip("/") + url_for("admin.demos")
    owner_body = (
        "A new demo appointment was requested from the JQC features site.\n\n"
        f"When:     {req.when} ({cfg['DEMO_TIMEZONE_LABEL']})\n"
        f"Name:     {req.name}\n"
        f"Company:  {req.company or '—'}\n"
        f"Email:    {req.email}\n"
        f"Phone:    {req.phone or '—'}\n\n"
        f"Message:\n{req.message or '—'}\n\n"
        f"Manage requests: {admin_link}\n"
    )
    send_email_async(
        cfg, cfg.get("DEMO_NOTIFY_EMAIL"),
        f"Demo request — {req.name} · {req.when}",
        owner_body,
        reply_to=req.email, reply_name=req.name,
    )

    if cfg.get("DEMO_CONFIRM_CUSTOMER"):
        send_email_async(
            cfg, req.email,
            "We received your demo request",
            (
                f"Hi {req.name},\n\n"
                "Thanks for your interest in JQC — LT Services' Janitorial "
                "Quality Control program.\n\n"
                f"You asked for a demonstration on {req.when} "
                f"({cfg['DEMO_TIMEZONE_LABEL']}). We'll confirm that time by "
                "email or phone shortly; if it turns out not to work on our "
                "side we'll suggest the nearest alternative.\n\n"
                "— LT Services Inc.\n"
            ),
        )


def _configure_auth_logger(app):
    """A dedicated 'jqc.auth' logger writing one line per login attempt to a
    file fail2ban watches. Kept separate from the app log so the filter regex
    stays tight and rotation is self-contained (no logrotate needed)."""
    log_path = app.config.get("AUTH_LOG_PATH") or os.path.join(
        os.path.dirname(os.path.abspath(__file__)), "logs", "auth.log"
    )
    os.makedirs(os.path.dirname(log_path), exist_ok=True)

    auth_log = logging.getLogger("jqc.auth")
    auth_log.setLevel(logging.INFO)
    auth_log.propagate = False
    # Guard against duplicate handlers if create_app runs more than once.
    if not any(isinstance(h, RotatingFileHandler) for h in auth_log.handlers):
        handler = RotatingFileHandler(
            log_path, maxBytes=1_000_000, backupCount=5, encoding="utf-8"
        )
        handler.setFormatter(
            logging.Formatter("%(asctime)s %(name)s %(levelname)s %(message)s")
        )
        auth_log.addHandler(handler)
    return auth_log


def create_app():
    app = Flask(__name__)
    app.config.from_object(Config)

    # Behind nginx: trust ONE proxy hop so request.remote_addr / scheme reflect
    # the real client (nginx sets X-Forwarded-For / -Proto). gunicorn binds
    # 127.0.0.1 only, so these headers can't be spoofed from outside.
    app.wsgi_app = ProxyFix(app.wsgi_app, x_for=1, x_proto=1, x_host=1)

    db.init_app(app)
    csrf.init_app(app)
    _configure_auth_logger(app)

    # Deferred import avoids a circular import: admin.py imports the models and
    # log_action defined above, which are ready by the time create_app() runs.
    from admin import admin_bp
    app.register_blueprint(admin_bp)

    @app.route("/")
    def index():
        all_sections = (
            Section.query.order_by(Section.sort_order, Section.num).all()
        )
        # Hide sections whose topics are all drafts (or which have no topics).
        sections = [s for s in all_sections if s.published_topics]
        return render_template(
            "index.html",
            sections=sections,
            demo_url=app.config["DEMO_CONTACT_URL"],
        )

    @app.route("/demo", methods=["GET", "POST"])
    def demo():
        """Public demo-appointment form. On success the request is stored and
        the owner is notified by mail (best-effort, on a background thread)."""
        cfg = app.config
        slots = demo_slots(cfg)
        today = date.today()
        max_date = today + timedelta(days=cfg["DEMO_MAX_DAYS_AHEAD"])
        form = {}

        if request.method == "POST":
            f = request.form
            form = {k: f.get(k, "").strip() for k in (
                "name", "company", "email", "phone", "preferred_date",
                "preferred_time", "message",
            )}
            errors = []

            # Honeypot: a hidden field only a bot fills in. Pretend success so
            # the bot doesn't learn to work around it.
            if f.get("website", "").strip():
                return redirect(url_for("demo_thanks"))

            client_ip = request.remote_addr or "-"
            if _rate_limited(client_ip, cfg["DEMO_RATE_LIMIT"]):
                errors.append(
                    "Too many requests from this connection. Please try again "
                    "later or email us directly."
                )

            if not form["name"]:
                errors.append("Please tell us your name.")
            if not EMAIL_RE.match(form["email"] or ""):
                errors.append("Please enter a valid email address.")

            try:
                wanted = datetime.strptime(form["preferred_date"], "%Y-%m-%d").date()
            except ValueError:
                wanted = None
                errors.append("Please pick a date for the demonstration.")
            if wanted:
                closed = demo_day_status(cfg, wanted)
                if closed:
                    errors.append(closed)

            if form["preferred_time"] not in slots:
                errors.append("Please pick an available time.")

            # One appointment per slot. Cancelled ones free the slot again.
            if not errors and DemoRequest.query.filter(
                DemoRequest.preferred_date == wanted,
                DemoRequest.preferred_time == form["preferred_time"],
                DemoRequest.status != "cancelled",
            ).first():
                errors.append("That time was just taken — please pick another.")

            if errors:
                for msg in errors:
                    flash(msg, "error")
            else:
                req = DemoRequest(
                    name=form["name"][:120],
                    company=form["company"][:160] or None,
                    email=form["email"][:200],
                    phone=form["phone"][:40] or None,
                    preferred_date=wanted,
                    preferred_time=form["preferred_time"],
                    message=form["message"][:2000] or None,
                    status="new",
                    source_ip=client_ip[:45],
                )
                db.session.add(req)
                db.session.commit()
                log_action(
                    "public", "create", "demo", req.id,
                    f"{req.name} · {req.when}",
                )
                _notify_demo(app, req)
                return redirect(url_for("demo_thanks"))

        # Show only what's still free on the date in hand, so a re-render after
        # an error can't offer a slot that was taken in the meantime. With no
        # date chosen yet the full grid is listed and the JS narrows it as soon
        # as one is picked (and without JS the checks above are the backstop).
        chosen = None
        if form.get("preferred_date"):
            try:
                chosen = datetime.strptime(form["preferred_date"], "%Y-%m-%d").date()
            except ValueError:
                chosen = None
        return render_template(
            "demo.html",
            slots=available_slots(cfg, chosen) if chosen else slots,
            form=form,
            min_date=today.isoformat(),
            max_date=max_date.isoformat(),
            tz_label=cfg["DEMO_TIMEZONE_LABEL"],
            demo_url=cfg["DEMO_CONTACT_URL"],
        )

    @app.route("/demo/slots")
    def demo_slots_api():
        """Times still bookable on ?date=YYYY-MM-DD, for the form's time picker.
        Public and read-only: it exposes which slots are free, which is exactly
        what the form shows anyway, and nothing about who booked them."""
        cfg = app.config
        raw = request.args.get("date", "")
        try:
            day = datetime.strptime(raw, "%Y-%m-%d").date()
        except ValueError:
            return jsonify(ok=False, error="Invalid date."), 400

        closed = demo_day_status(cfg, day)
        if closed:
            return jsonify(ok=True, date=raw, open=False, reason=closed, slots=[])
        return jsonify(ok=True, date=raw, open=True, slots=available_slots(cfg, day))

    @app.route("/demo/thanks")
    def demo_thanks():
        return render_template("demo_thanks.html", demo_url=app.config["DEMO_CONTACT_URL"])

    @app.route("/healthz")
    def healthz():
        return {"status": "ok"}

    @app.context_processor
    def inject_asset_url():
        """`asset_url('css/style.css')` → the static URL with a `?v=<mtime>`
        cache-buster, so an edited CSS/JS file is always re-fetched instead of
        being served stale from the browser/proxy cache."""
        from flask import url_for

        def asset_url(filename):
            try:
                version = int(os.path.getmtime(
                    os.path.join(app.static_folder, filename)))
            except OSError:
                version = 0
            return url_for("static", filename=filename, v=version)

        return {"asset_url": asset_url}

    return app


app = create_app()


if __name__ == "__main__":
    app.run(host="127.0.0.1", port=8000, debug=True)