from __future__ import annotations

import datetime
import json
import logging
import sys
from dataclasses import asdict, dataclass
from enum import Enum
from typing import Any, Dict, List, NewType, Optional, Tuple, Union

import requests

from piket_server.flask import db
from piket_server.models import Person
from piket_server.util import fmt_datetime

# AARDBEI_ENDPOINT = "https://aardbei.app"
AARDBEI_ENDPOINT = "http://localhost:3000"
log = logging.getLogger(__name__)

ActivityId = NewType("ActivityId", int)
PersonId = NewType("PersonId", int)
MemberId = NewType("MemberId", int)
ParticipantId = NewType("ParticipantId", int)


@dataclass(frozen=True)
class AardbeiPerson:
    """
    Contains the data on a Person as exposed by Aardbei.

    A Person represents a person in the real world, and maps to a Person in the local database.
    """

    aardbei_id: PersonId
    full_name: str

    @classmethod
    def from_aardbei_dict(cls, data: Dict[str, Any]) -> AardbeiPerson:
        """
        Load from a dictionary provided by Aardbei.

        >>> AardbeiPerson.from_aardbei_dict(
          {"person": {"aardbei_id": 1, "full_name": "Henkie Kraggelwenk"}}
        )
        AardbeiPerson(aardbei_id=AardbeiId(1), full_name="Henkie Kraggelwenk")
        """

        d = data["person"]
        return cls(full_name=d["full_name"], aardbei_id=PersonId(d["id"]))

    @property
    def as_json_dict(self) -> Dict[str, Any]:
        """
        Serialize to a dictionary as provided by Aardbei.

        >>> AardbeiPerson(aardbei_id=AardbeiId(1), full_name="Henkie Kraggelwenk").as_json_dict
        {"person": {"id": 1, "full_name": "Henkie Kraggelwenk"}}
        """

        return {"person": {"id": self.aardbei_id, "full_name": self.full_name}}


@dataclass(frozen=True)
class AardbeiMember:
    """
    Contains the data on a Member exposed by Aardbei.

    A Member represents the membership of a Person in a Group in Aardbei.
    """

    person: AardbeiPerson
    aardbei_id: MemberId
    is_leader: bool
    display_name: str

    @classmethod
    def from_aardbei_dict(cls, data: Dict[str, Any]) -> AardbeiMember:
        """
        Load from a dictionary provided by Aardbei.

        >>> from_aardbei_dict({
            "member": {
                "person": {
                    "full_name": "Roer Kuggelvork",
                    "id": 2,
                },
                "id": 23,
                "is_leader": False,
                "display_name": "Roer",
            },
        })
        AardbeiMember(
            person=AardbeiPerson(aardbei_id=PersonId(2), full_name="Roer Kuggelvork"),
            aardbei_id=MemberId(23),
            is_leader=False,
            display_name="Roer",
        )
        """

        d = data["member"]
        person = AardbeiPerson.from_aardbei_dict(d)
        return cls(
            person=person,
            aardbei_id=MemberId(d["id"]),
            is_leader=d["is_leader"],
            display_name=d["display_name"],
        )

    @property
    def as_json_dict(self) -> Dict[str, Any]:
        """
        Serialize to a dict as provided by Aardbei.

        >>> AardbeiMember(
            person=AardbeiPerson(aardbei_id=PersonId(2), full_name="Roer Kuggelvork"),
            aardbei_id=MemberId(23),
            is_leader=False,
            display_name="Roer",
        )
        {
            "member": {
                "person": {
                    "full_name": "Roer Kuggelvork",
                    "id": 2,
                },
                "id": 23,
                "is_leader": False,
                "display_name": "Roer",
            }
        }
        """
        res = {
            "id": self.aardbei_id,
            "is_leader": self.is_leader,
            "display_name": self.display_name,
        }
        res.update(self.person.as_json_dict)
        return res


@dataclass(frozen=True)
class AardbeiParticipant:
    """
    Represents a Participant as exposed by Aardbei.

    A Participant represents the participation of a Person (optionally as a Member in a Group) in an Activity.
    """

    person: AardbeiPerson
    member: Optional[AardbeiMember]
    aardbei_id: ParticipantId
    attending: bool
    is_organizer: bool
    notes: Optional[str]

    @property
    def name(self) -> str:
        """
        Return the name to show for this Participant.
        This is the display_name if a Member is present, else the Participant's Person's full name.
        """
        if self.member is not None:
            return self.member.display_name

        return self.person.full_name

    @classmethod
    def from_aardbei_dict(cls, data: Dict[str, Any]) -> AardbeiParticipant:
        """
        Load from a dictionary as provided by Aardbei.
        """
        d = data["participant"]
        person = AardbeiPerson.from_aardbei_dict(d)

        member: Optional[AardbeiMember] = None
        if d["member"] is not None:
            member = AardbeiMember.from_aardbei_dict(d)

        aardbei_id = ParticipantId(d["id"])

        return cls(
            person=person,
            member=member,
            aardbei_id=aardbei_id,
            attending=d["attending"],
            is_organizer=d["is_organizer"],
            notes=d["notes"],
        )

    @property
    def as_json_dict(self) -> Dict[str, Any]:
        """
        Serialize to a dict as provided by Aardbei.
        """
        res = {
            "participant": {
                "id": self.aardbei_id,
                "attending": self.attending,
                "is_organizer": self.is_organizer,
                "notes": self.notes,
            }
        }
        res.update(self.person.as_json_dict)
        if self.member is not None:
            res.update(self.member.as_json_dict)

        return res


class NoResponseAction(Enum):
    """Represents the "no response action" attribute of Activities in Aardbei."""

    Present = "present"
    Absent = "absent"


@dataclass(frozen=True)
class ResponseCounts:
    """Represents the "response counts" attribute of Activities in Aardbei."""

    present: int
    absent: int
    unknown: int

    @classmethod
    def from_aardbei_dict(cls, data: Dict[str, int]) -> ResponseCounts:
        """Load from a dict as provided by Aardbei."""
        return cls(
            present=data["present"], absent=data["absent"], unknown=data["unknown"]
        )

    @property
    def as_json_dict(self) -> Dict[str, int]:
        """Serialize to a dict as provided by Aardbei."""
        return {"present": self.present, "absent": self.absent, "unknown": self.unknown}


@dataclass(frozen=True)
class SparseAardbeiActivity:
    aardbei_id: ActivityId
    name: str
    description: str
    location: str
    start: datetime.datetime
    end: Optional[datetime.datetime]
    deadline: Optional[datetime.datetime]
    reminder_at: Optional[datetime.datetime]
    no_response_action: NoResponseAction
    response_counts: ResponseCounts

    def distance(self, reference: datetime.datetime) -> datetime.timedelta:
        """Calculate how long ago this Activity ended / how much time until it starts."""
        if self.end is not None:
            if reference > self.start and reference < self.end:
                return datetime.timedelta(seconds=0)

            elif reference < self.start:
                return self.start - reference

            elif reference > self.end:
                return reference - self.end

        if reference > self.start:
            return reference - self.start

        return self.start - reference

    @classmethod
    def from_aardbei_dict(cls, data: Dict[str, Any]) -> SparseAardbeiActivity:
        """Load from a dict as provided by Aardbei."""
        start: datetime.datetime = datetime.datetime.fromisoformat(
            data["activity"]["start"]
        )
        end: Optional[datetime.datetime] = None

        if data["activity"]["end"] is not None:
            end = datetime.datetime.fromisoformat(data["activity"]["end"])

        deadline: Optional[datetime.datetime] = None
        if data["activity"]["deadline"] is not None:
            deadline = datetime.datetime.fromisoformat(data["activity"]["deadline"])

        reminder_at: Optional[datetime.datetime] = None
        if data["activity"]["reminder_at"] is not None:
            reminder_at = datetime.datetime.fromisoformat(
                data["activity"]["reminder_at"]
            )

        no_response_action = NoResponseAction(data["activity"]["no_response_action"])

        response_counts = ResponseCounts.from_aardbei_dict(
            data["activity"]["response_counts"]
        )

        return cls(
            aardbei_id=ActivityId(data["activity"]["id"]),
            name=data["activity"]["name"],
            description=data["activity"]["description"],
            location=data["activity"]["location"],
            start=start,
            end=end,
            deadline=deadline,
            reminder_at=reminder_at,
            no_response_action=no_response_action,
            response_counts=response_counts,
        )

    @property
    def as_json_dict(self) -> Dict[str, Any]:
        """Serialize to a dict as provided by Aardbei."""
        return {
            "activity": {
                "id": self.aardbei_id,
                "name": self.name,
                "description": self.description,
                "location": self.location,
                "start": fmt_datetime(self.start),
                "end": fmt_datetime(self.end),
                "deadline": fmt_datetime(self.deadline),
                "reminder_at": fmt_datetime(self.reminder_at),
                "no_response_action": self.no_response_action.value,
                "response_counts": self.response_counts.as_json_dict,
            }
        }


@dataclass(frozen=True)
class AardbeiActivity(SparseAardbeiActivity):
    """Contains the data of an Activity as exposed by Aardbei."""

    participants: List[AardbeiParticipant]

    @classmethod
    def from_aardbei_dict(cls, data: Dict[str, Any]) -> AardbeiActivity:
        """Load from a dict as provided by Aardbei."""
        # Ugly: This is a copy of the Sparse variant with added participants.
        # This is not ideal, but I don't care enough to fix this right now.
        participants: List[AardbeiParticipant] = [
            AardbeiParticipant.from_aardbei_dict(x)
            for x in data["activity"]["participants"]
        ]

        start: datetime.datetime = datetime.datetime.fromisoformat(
            data["activity"]["start"]
        )
        end: Optional[datetime.datetime] = None

        if data["activity"]["end"] is not None:
            end = datetime.datetime.fromisoformat(data["activity"]["end"])

        deadline: Optional[datetime.datetime] = None
        if data["activity"]["deadline"] is not None:
            deadline = datetime.datetime.fromisoformat(data["activity"]["deadline"])

        reminder_at: Optional[datetime.datetime] = None
        if data["activity"]["reminder_at"] is not None:
            reminder_at = datetime.datetime.fromisoformat(
                data["activity"]["reminder_at"]
            )

        no_response_action = NoResponseAction(data["activity"]["no_response_action"])

        response_counts = ResponseCounts.from_aardbei_dict(
            data["activity"]["response_counts"]
        )

        return cls(
            aardbei_id=ActivityId(data["activity"]["id"]),
            name=data["activity"]["name"],
            description=data["activity"]["description"],
            location=data["activity"]["location"],
            start=start,
            end=end,
            deadline=deadline,
            reminder_at=reminder_at,
            no_response_action=no_response_action,
            response_counts=response_counts,
            participants=participants,
        )

    @property
    def as_json_dict(self) -> Dict[str, Any]:
        """Serialize to a dict as provided by Aardbei."""
        res = super().as_json_dict
        res["participants"] = [p.as_json_dict for p in self.participants]
        return res


@dataclass(frozen=True)
class AardbeiMatch:
    """Represents a match between a local Person and a Person present in Aardbei's data."""

    local: Person
    remote: AardbeiMember


@dataclass(frozen=True)
class AardbeiLink:
    """Represents a set of differences between the local state and Aardbei's set of people."""

    matches: List[AardbeiMatch]
    """People that exist on both sides, but aren't linked in the people table."""
    altered_name: List[AardbeiMatch]
    """People that are already linked but changed one of their names."""
    remote_only: List[AardbeiMember]
    """People that only exist on the remote."""

    @property
    def num_changes(self) -> int:
        """Return the amount of mismatching people between Aardbei and the local state."""
        return len(self.matches) + len(self.altered_name) + len(self.remote_only)


class AardbeiSyncError(Enum):
    """Represents errors that might occur when retrieving data from Aardbei."""

    CantConnect = "connect_fail"
    HTTPError = "http_fail"


def get_aardbei_people(
    token: str, endpoint: str = AARDBEI_ENDPOINT
) -> Union[List[AardbeiMember], AardbeiSyncError]:
    """Retrieve the set of People in a Group from Aardbei, and parse this to
    AardbeiPerson objects. Return a AardbeiSyncError if something fails."""
    try:
        resp: requests.Response = requests.get(
            f"{endpoint}/api/groups/0/",
            headers={"Authorization": f"Group {token}"},
        )
        resp.raise_for_status()

    except requests.ConnectionError as e:
        log.exception("Can't connect to endpoint %s", endpoint)
        return AardbeiSyncError.CantConnect

    except requests.HTTPError:
        return AardbeiSyncError.HTTPError

    members = resp.json()["group"]["members"]

    return [AardbeiMember.from_aardbei_dict(x) for x in members]


def match_local_aardbei(aardbei_members: List[AardbeiMember]) -> AardbeiLink:
    """Inspect the local state and compare it with the set of given
    AardbeiMembers (containing AardbeiPersons). Return a AardbeiLink that
    indicates which local people don't match the remote state."""

    matches: List[AardbeiMatch] = []
    altered_name: List[AardbeiMatch] = []
    remote_only: List[AardbeiMember] = []

    for member in aardbei_members:
        p: Optional[Person] = Person.query.filter_by(
            aardbei_id=member.person.aardbei_id
        ).one_or_none()

        if p is not None:
            if (
                p.full_name != member.person.full_name
                or p.display_name != member.display_name
            ):
                altered_name.append(AardbeiMatch(p, member))

            else:
                logging.info(
                    "OK: %s / %s (L%s/R%s)",
                    p.full_name,
                    p.display_name,
                    p.person_id,
                    p.aardbei_id,
                )

            continue

        p = Person.query.filter_by(full_name=member.person.full_name).one_or_none()

        if p is not None:
            matches.append(AardbeiMatch(p, member))
        else:
            remote_only.append(member)

    return AardbeiLink(matches, altered_name, remote_only)


def link_matches(matches: List[AardbeiMatch]) -> None:
    """
    Update local people to add the remote ID to the local state.
    This only enqueues the changes in the local SQLAlchemy session, committing
    needs to be done separately.
    """

    for match in matches:
        match.local.aardbei_id = match.remote.person.aardbei_id
        match.local.display_name = match.remote.display_name
        logging.info(
            "Linking local %s (%s) to remote %s (%s)",
            match.local.full_name,
            match.local.person_id,
            match.remote.display_name,
            match.remote.person.aardbei_id,
        )

        db.session.add(match.local)


def create_missing(missing: List[AardbeiMember]) -> None:
    """
    Create local people for all remote people that don't exist locally.
    This only enqueues the changes in the local SQLAlchemy session, committing
    needs to be done separately.
    """

    for member in missing:
        pnew = Person(
            full_name=member.person.full_name,
            display_name=member.display_name,
            aardbei_id=member.person.aardbei_id,
            active=False,
        )
        logging.info(
            "Creating new person for %s / %s (%s)",
            member.person.full_name,
            member.display_name,
            member.person.aardbei_id,
        )
        db.session.add(pnew)


def update_names(matches: List[AardbeiMatch]) -> None:
    """
    Update the local full and display names of people that were already linked
    to a remote person, and who changed names on the remote.

    This only enqueues the changes in the local SQLAlchemy session, committing
    needs to be done separately.
    """

    for match in matches:
        p = match.local
        member = match.remote
        aardbei_person = member.person

        changed = False

        if p.full_name != aardbei_person.full_name:
            logging.info(
                "Updating %s (L%s/R%s) full name %s to %s",
                aardbei_person.full_name,
                p.person_id,
                aardbei_person.aardbei_id,
                p.full_name,
                aardbei_person.full_name,
            )
            p.full_name = aardbei_person.full_name
            changed = True

        if p.display_name != member.display_name:
            logging.info(
                "Updating %s (L%s/R%s) display name %s to %s",
                p.full_name,
                p.person_id,
                aardbei_person.aardbei_id,
                p.display_name,
                member.display_name,
            )
            p.display_name = member.display_name
            changed = True

        assert changed, "got match but didn't update anything"

        db.session.add(p)


def get_activities(
    token: str, endpoint: str = AARDBEI_ENDPOINT
) -> Union[List[SparseAardbeiActivity], AardbeiSyncError]:
    """
    Get the list of activities present on the remote and return these
    activities, ordered by the temporal distance to the current time.
    """

    result: List[SparseAardbeiActivity] = []

    for category in ("upcoming", "current", "previous"):
        try:
            resp = requests.get(
                f"{endpoint}/api/groups/0/{category}_activities",
                headers={"Authorization": f"Group {token}"},
            )

            resp.raise_for_status()

        except requests.HTTPError as e:
            log.exception(e)
            return AardbeiSyncError.HTTPError

        except requests.ConnectionError as e:
            log.exception(e)
            return AardbeiSyncError.CantConnect

        for item in resp.json():
            result.append(SparseAardbeiActivity.from_aardbei_dict(item))

    now = datetime.datetime.now(datetime.timezone.utc)
    result.sort(key=lambda x: SparseAardbeiActivity.distance(x, now))
    return result


def get_activity(
    activity_id: ActivityId, token: str, endpoint: str
) -> Union[AardbeiActivity, AardbeiSyncError]:
    """
    Get all data (including participants) from the remote about one activity
    with a given ID.
    """

    try:
        resp = requests.get(
            f"{endpoint}/api/activities/{activity_id}",
            headers={"Authorization": f"Group {token}"},
        )

        resp.raise_for_status()

    except requests.HTTPError as e:
        log.exception(e)
        return AardbeiSyncError.HTTPError

    except requests.ConnectionError as e:
        return AardbeiSyncError.CantConnect

    return AardbeiActivity.from_aardbei_dict(resp.json())


def match_activity(activity: AardbeiActivity) -> None:
    """
    Update the local state to have mark all people present at the given
    activity as active, and all other people as inactive.
    """
    ps = activity.participants
    pids: List[PersonId] = [p.person.aardbei_id for p in ps if p.attending]

    Person.query.update(values={"active": False})
    Person.query.filter(Person.aardbei_id.in_(pids)).update(
        values={"active": True}, synchronize_session="fetch"
    )


if __name__ == "__main__":
    logging.basicConfig(level=logging.DEBUG)

    token = input("Token: ")
    aardbei_people = get_aardbei_people(token)

    if isinstance(aardbei_people, AardbeiSyncError):
        logging.error("Could not get people: %s", aardbei_people.value)
        sys.exit(1)

    activities = get_activities(token)

    if isinstance(activities, AardbeiSyncError):
        logging.error("Could not get activities: %s", activities.value)
        sys.exit(1)

    link = match_local_aardbei(aardbei_people)

    link_matches(link.matches)
    create_missing(link.remote_only)
    update_names(link.altered_name)

    confirm = input("Commit? Y/N")
    if confirm.lower() == "y":
        print("Committing.")
        db.session.commit()
    else:
        print("Not committing.")