"""The brew-process pages: record readings and review the runs."""

from __future__ import annotations

from flask import (Blueprint, flash, redirect, render_template, request,
                   session, url_for)
from flask_wtf import FlaskForm
from wtforms import (BooleanField, DateField, IntegerField, StringField,
                     SubmitField, TextAreaField)
from wtforms.validators import DataRequired, Length, NumberRange, Optional

from brewing import is_plausible_sg, run_summary

bp = Blueprint("brews", __name__)


def repo():
    """The request-scoped repository (one Mongo client per request)."""
    from flask import current_app

    return current_app.extensions["beer_repo"]()


def login_required(fn):
    """Redirect to the login page when there is no session."""
    from functools import wraps

    @wraps(fn)
    def wrapper(*args, **kwargs):
        if not session.get("logged_in"):
            return redirect(url_for("auth.login", next=request.path))
        return fn(*args, **kwargs)

    return wrapper


def _last_reading_date(run) -> str | None:
    """The ISO date of the most recent reading in a run."""
    last = run.last_reading()
    if last is None or last.date is None:
        return None
    return last.date.isoformat()


class ReadingForm(FlaskForm):
    """Add or update a gravity reading."""

    beer_run_id = IntegerField("Run number", validators=[DataRequired()])
    beer_run_type = StringField("Beer / cider name",
                                validators=[Optional(), Length(max=120)])
    Date = DateField("Reading date", validators=[DataRequired()])
    sg = IntegerField("Gravity reading (points)",
                      validators=[DataRequired(), NumberRange(min=900, max=1300)])
    final_reading = BooleanField("This is the final reading")
    comment = TextAreaField("Comment", validators=[Optional(), Length(max=2000)])
    submit = SubmitField("Save reading")


@bp.route("/brews", methods=["GET", "POST"])
@login_required
def index():
    """The brew-process page: record a reading, then review the runs."""
    form = ReadingForm()

    if form.validate_on_submit():
        sg_points = int(form.sg.data)
        if not is_plausible_sg(sg_points):
            flash(
                f"{sg_points} is outside the usual hydrometer range "
                "(990-1200). It was saved anyway — double-check the reading.",
                "warning",
            )
        repo().upsert_reading(
            beer_run_id=str(form.beer_run_id.data),
            beer_type=(form.beer_run_type.data or "").strip(),
            sg=sg_points,
            reading_date=form.Date.data.isoformat(),
            final_reading=bool(form.final_reading.data),
            comment=(form.comment.data or "").strip(),
        )
        flash("Reading saved.", "success")
        return redirect(url_for("brews.index"))

    runs = repo().runs()

    summaries = []
    for run in runs:
        summary = run_summary(run)
        summary["canonical_name"] = run.display_name()
        summary["last_date"] = _last_reading_date(run)
        summaries.append(summary)

    # Active runs: most recent activity first — that is what is fermenting now.
    active = sorted([s for s in summaries if s["active"]],
                     key=lambda s: s["last_date"] or "", reverse=True)
    # Finished runs: most recently finished first.
    completed = sorted([s for s in summaries if not s["active"]],
                       key=lambda s: s["final_date"] or "", reverse=True)

    return render_template(
        "brews.html",
        form=form,
        summaries=summaries,
        active_runs=active,
        completed_runs=completed,
    )


@bp.route("/runs/<run_id>")
@login_required
def run_detail(run_id: str):
    """One run in detail, with all of its readings."""
    run = repo().run(run_id)
    if run is None:
        flash(f"No run numbered {run_id}.", "error")
        return redirect(url_for("brews.index"))

    summary = run_summary(run)
    summary["canonical_name"] = run.display_name()

    return render_template("run_detail.html", run=run, summary=summary)


@bp.route("/runs/<run_id>/final", methods=["POST"])
@login_required
def mark_final(run_id: str):
    """Flag a reading as the final one for its run."""
    reading_date = request.form.get("date", "")
    if not reading_date:
        flash("No reading date supplied.", "error")
        return redirect(url_for("brews.run_detail", run_id=run_id))

    changed = repo().set_final_reading(run_id, reading_date, True)
    if changed:
        flash("Final reading recorded.", "success")
    else:
        flash("That reading could not be updated.", "error")
    return redirect(url_for("brews.run_detail", run_id=run_id))


@bp.route("/runs/<run_id>/unfinal", methods=["POST"])
@login_required
def unfinal(run_id: str):
    """Un-flag a final reading, putting the run back into the active list."""
    reading_date = request.form.get("date", "")
    if not reading_date:
        flash("No reading date supplied.", "error")
        return redirect(url_for("brews.run_detail", run_id=run_id))

    repo().set_final_reading(run_id, reading_date, False)
    flash("Reading is no longer marked final.", "info")
    return redirect(url_for("brews.run_detail", run_id=run_id))