"""
Piket server, handles events generated by the client.
"""

import datetime
import os

from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy import func
from flask import Flask, jsonify, abort, request
from flask_sqlalchemy import SQLAlchemy


DATA_HOME = os.environ.get("XDG_DATA_HOME", "~/.local/share")
CONFIG_DIR = os.path.join(DATA_HOME, "piket_server")
DB_PATH = os.path.expanduser(os.path.join(CONFIG_DIR, "database.sqlite3"))
DB_URL = f"sqlite:///{DB_PATH}"

app = Flask("piket_server")
app.config["SQLALCHEMY_DATABASE_URI"] = DB_URL
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
db = SQLAlchemy(app)


# ---------- Models ----------
class Person(db.Model):
    """ Represents a person to be shown on the lists. """

    __tablename__ = "people"

    person_id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String, nullable=False)
    active = db.Column(db.Boolean, nullable=False, default=False)

    consumptions = db.relationship("Consumption", backref="person", lazy=True)

    def __repr__(self) -> str:
        return f"<Person {self.person_id}: {self.name}>"

    @property
    def as_dict(self) -> dict:
        return {
            "person_id": self.person_id,
            "active": self.active,
            "name": self.name,
            "consumptions": {
                ct.consumption_type_id: Consumption.query.filter_by(person=self)
                .filter_by(settlement=None)
                .filter_by(consumption_type=ct)
                .filter_by(reversed=False)
                .count()
                for ct in ConsumptionType.query.all()
            },
        }


class Export(db.Model):
    """ Represents a set of exported Settlements. """

    __tablename__ = "exports"

    export_id = db.Column(db.Integer, primary_key=True)
    created_at = db.Column(
        db.DateTime, default=datetime.datetime.utcnow, nullable=False
    )

    settlements = db.relationship("Settlement", backref="export", lazy=True)

    @property
    def as_dict(self) -> dict:
        return {
            "export_id": self.export_id,
            "created_at": self.created_at.isoformat(),
            "settlement_ids": [s.settlement_id for s in self.settlements],
        }


class Settlement(db.Model):
    """ Represents a settlement of the list. """

    __tablename__ = "settlements"

    settlement_id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String, nullable=False)
    export_id = db.Column(db.Integer, db.ForeignKey("exports.export_id"), nullable=True)

    consumptions = db.relationship("Consumption", backref="settlement", lazy=True)

    def __repr__(self) -> str:
        return f"<Settlement {self.settlement_id}: {self.name}>"

    @property
    def as_dict(self) -> dict:
        return {
            "settlement_id": self.settlement_id,
            "name": self.name,
            "consumption_summary": self.consumption_summary,
            "unique_people": self.unique_people,
        }

    @property
    def unique_people(self) -> int:
        q = (
            Consumption.query.filter_by(settlement=self)
            .filter_by(reversed=False)
            .group_by(Consumption.person_id)
            .count()
        )
        return q

    @property
    def consumption_summary(self) -> dict:
        q = (
            Consumption.query.filter_by(settlement=self)
            .filter_by(reversed=False)
            .group_by(Consumption.consumption_type_id)
            .order_by(ConsumptionType.name)
            .outerjoin(ConsumptionType)
            .with_entities(
                Consumption.consumption_type_id,
                ConsumptionType.name,
                func.count(Consumption.consumption_id),
            )
            .all()
        )

        return {r[0]: {"name": r[1], "count": r[2]} for r in q}

    @property
    def per_person(self) -> dict:
        # Get keys of seen consumption_types
        c_types = self.consumption_summary.keys()

        result = {}
        for type in c_types:
            c_type = ConsumptionType.query.get(type)
            result[type] = {"consumption_type": c_type.as_dict, "counts": {}}

            q = (
                Consumption.query.filter_by(settlement=self)
                .filter_by(reversed=False)
                .filter_by(consumption_type=c_type)
                .group_by(Consumption.person_id)
                .order_by(Person.name)
                .outerjoin(Person)
                .with_entities(
                    Person.person_id,
                    Person.name,
                    func.count(Consumption.consumption_id),
                )
                .all()
            )

            for row in q:
                result[type]["counts"][row[0]] = {"name": row[1], "count": row[2]}

        return result


class ConsumptionType(db.Model):
    """ Represents a type of consumption to be counted. """

    __tablename__ = "consumption_types"

    consumption_type_id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String, nullable=False)
    icon = db.Column(db.String)

    consumptions = db.relationship("Consumption", backref="consumption_type", lazy=True)

    def __repr__(self) -> str:
        return f"<ConsumptionType: {self.name}>"

    @property
    def as_dict(self) -> dict:
        return {
            "consumption_type_id": self.consumption_type_id,
            "name": self.name,
            "icon": self.icon,
        }


class Consumption(db.Model):
    """ Represent one consumption to be counted. """

    __tablename__ = "consumptions"

    consumption_id = db.Column(db.Integer, primary_key=True)
    person_id = db.Column(db.Integer, db.ForeignKey("people.person_id"), nullable=True)
    consumption_type_id = db.Column(
        db.Integer,
        db.ForeignKey("consumption_types.consumption_type_id"),
        nullable=False,
    )
    settlement_id = db.Column(
        db.Integer, db.ForeignKey("settlements.settlement_id"), nullable=True
    )
    created_at = db.Column(
        db.DateTime, default=datetime.datetime.utcnow, nullable=False
    )
    reversed = db.Column(db.Boolean, default=False, nullable=False)

    def __repr__(self) -> str:
        return f"<Consumption: {self.consumption_type.name} for {self.person.name}>"

    @property
    def as_dict(self) -> dict:
        return {
            "consumption_id": self.consumption_id,
            "person_id": self.person_id,
            "consumption_type_id": self.consumption_type_id,
            "settlement_id": self.settlement_id,
            "created_at": self.created_at.isoformat(),
            "reversed": self.reversed,
        }


# ---------- Models ----------


@app.route("/ping")
def ping() -> None:
    """ Return a status ping. """
    return "Pong"


@app.route("/status")
def status() -> None:
    """ Return a status dict with info about the database. """
    unsettled_q = Consumption.query.filter_by(settlement=None).filter_by(reversed=False)

    unsettled = unsettled_q.count()

    first = None
    last = None
    if unsettled:
        last = (
            unsettled_q.order_by(Consumption.created_at.desc())
            .first()
            .created_at.isoformat()
        )
        first = (
            unsettled_q.order_by(Consumption.created_at.asc())
            .first()
            .created_at.isoformat()
        )

    return jsonify({"unsettled": {"amount": unsettled, "first": first, "last": last}})


# Person
@app.route("/people", methods=["GET"])
def get_people():
    """ Return a list of currently known people. """
    people = Person.query.order_by(Person.name).all()
    q = Person.query.order_by(Person.name)
    if request.args.get("active"):
        active_status = request.args.get("active", type=int)
        q = q.filter_by(active=active_status)
    people = q.all()
    result = [person.as_dict for person in people]
    return jsonify(people=result)


@app.route("/people/<int:person_id>", methods=["GET"])
def get_person(person_id: int):
    person = Person.query.get_or_404(person_id)

    return jsonify(person=person.as_dict)


@app.route("/people", methods=["POST"])
def add_person():
    """
    Add a new person.

    Required parameters:
    - name (str)
    """
    json = request.get_json()

    if not json:
        return jsonify({"error": "Could not parse JSON."}), 400

    data = json.get("person") or {}
    person = Person(name=data.get("name"), active=data.get("active", False))

    try:
        db.session.add(person)
        db.session.commit()
    except SQLAlchemyError:
        return jsonify({"error": "Invalid arguments for Person."}), 400

    return jsonify(person=person.as_dict), 201


@app.route("/people/<int:person_id>/add_consumption", methods=["POST"])
def add_consumption(person_id: int):
    person = Person.query.get_or_404(person_id)

    consumption = Consumption(person=person, consumption_type_id=1)
    try:
        db.session.add(consumption)
        db.session.commit()
    except SQLAlchemyError:
        return (
            jsonify(
                {"error": "Invalid Consumption parameters.", "person": person.as_dict}
            ),
            400,
        )

    return jsonify(person=person.as_dict, consumption=consumption.as_dict), 201


@app.route("/people/<int:person_id>", methods=["PATCH"])
def update_person(person_id: int):
    person = Person.query.get_or_404(person_id)

    data = request.json["person"]

    if "active" in data:
        person.active = data["active"]

        db.session.add(person)
        db.session.commit()

        return jsonify(person=person.as_dict)


@app.route("/people/<int:person_id>/add_consumption/<int:ct_id>", methods=["POST"])
def add_consumption2(person_id: int, ct_id: int):
    person = Person.query.get_or_404(person_id)

    consumption = Consumption(person=person, consumption_type_id=ct_id)
    try:
        db.session.add(consumption)
        db.session.commit()
    except SQLAlchemyError:
        return (
            jsonify(
                {"error": "Invalid Consumption parameters.", "person": person.as_dict}
            ),
            400,
        )

    return jsonify(person=person.as_dict, consumption=consumption.as_dict), 201


@app.route("/consumptions/<int:consumption_id>", methods=["DELETE"])
def reverse_consumption(consumption_id: int):
    """ Reverse a consumption. """
    consumption = Consumption.query.get_or_404(consumption_id)

    if consumption.reversed:
        return (
            jsonify(
                {
                    "error": "Consumption already reversed",
                    "consumption": consumption.as_dict,
                }
            ),
            409,
        )

    try:
        consumption.reversed = True
        db.session.add(consumption)
        db.session.commit()

    except SQLAlchemyError:
        return jsonify({"error": "Database error."}), 500

    return jsonify(consumption=consumption.as_dict), 200


# ConsumptionType
@app.route("/consumption_types", methods=["GET"])
def get_consumption_types():
    """ Return a list of currently active consumption types. """
    ctypes = ConsumptionType.query.all()
    result = [ct.as_dict for ct in ctypes]
    return jsonify(consumption_types=result)


@app.route("/consumption_types/<int:consumption_type_id>", methods=["GET"])
def get_consumption_type(consumption_type_id: int):
    ct = ConsumptionType.query.get_or_404(consumption_type_id)

    return jsonify(consumption_type=ct.as_dict)


@app.route("/consumption_types", methods=["POST"])
def add_consumption_type():
    """ Add a new ConsumptionType.  """
    json = request.get_json()

    if not json:
        return jsonify({"error": "Could not parse JSON."}), 400

    data = json.get("consumption_type") or {}
    ct = ConsumptionType(name=data.get("name"), icon=data.get("icon"))

    try:
        db.session.add(ct)
        db.session.commit()
    except SQLAlchemyError:
        return jsonify({"error": "Invalid arguments for ConsumptionType."}), 400

    return jsonify(consumption_type=ct.as_dict), 201


# Settlement
@app.route("/settlements", methods=["GET"])
def get_settlements():
    """ Return a list of the active Settlements. """
    result = Settlement.query.all()
    return jsonify(settlements=[s.as_dict for s in result])


@app.route("/settlements/<int:settlement_id>", methods=["GET"])
def get_settlement(settlement_id: int):
    """ Show full details for a single Settlement. """
    s = Settlement.query.get_or_404(settlement_id)

    per_person = s.per_person

    return jsonify(settlement=s.as_dict, count_info=per_person)


@app.route("/settlements", methods=["POST"])
def add_settlement():
    """ Create a Settlement, and link all un-settled Consumptions to it. """
    json = request.get_json()

    if not json:
        return jsonify({"error": "Could not parse JSON."}), 400

    data = json.get("settlement") or {}
    s = Settlement(name=data["name"])

    db.session.add(s)
    db.session.commit()

    Consumption.query.filter_by(settlement=None).update(
        {"settlement_id": s.settlement_id}
    )

    db.session.commit()

    return jsonify(settlement=s.as_dict)


# Export
@app.route("/exports", methods=["GET"])
def get_exports():
    """ Return a list of the created Exports. """
    result = Export.query.all()
    return jsonify(exports=[e.as_dict for e in result])


@app.route("/exports/<int:export_id>", methods=["GET"])
def get_export(export_id: int):
    """ Return an overview for the given Export. """
    e = Export.query.get_or_404(export_id)

    ss = [s.as_dict for s in e.settlements]

    return jsonify(export=e.as_dict, settlements=ss)


@app.route("/exports", methods=["POST"])
def add_export():
    """ Create an Export, and link all un-exported Settlements to it. """
    # Assert that there are Settlements to be exported.
    s_count = Settlement.query.filter_by(export=None).count()
    if s_count == 0:
        return jsonify(error="No un-exported Settlements."), 403

    e = Export()

    db.session.add(e)
    db.session.commit()

    Settlement.query.filter_by(export=None).update({"export_id": e.export_id})
    db.session.commit()

    ss = [s.as_dict for s in e.settlements]

    return jsonify(export=e.as_dict, settlements=ss), 201