from collections.abc import Collection

import pandas as pd

from config.models import SMS, Call, Participant
from setup import db_engine, session

call_types = {1: "incoming", 2: "outgoing", 3: "missed"}
sms_types = {1: "received", 2: "sent"}


def get_call_data(usernames: Collection) -> pd.DataFrame:
    """
    Read the data from the calls table and return it in a dataframe.

    Parameters
    ----------
    usernames: Collection
        A list of usernames to put into the WHERE condition.

    Returns
    -------
    df_calls: pd.DataFrame
        A dataframe of call data.
    """
    query_calls = (
        session.query(Call, Participant.username)
        .filter(Participant.id == Call.participant_id)
        .filter(Participant.username.in_(usernames))
    )
    with db_engine.connect() as connection:
        df_calls = pd.read_sql(query_calls.statement, connection)
    return df_calls


def get_sms_data(usernames: Collection) -> pd.DataFrame:
    """
    Read the data from the sms table and return it in a dataframe.

    Parameters
    ----------
    usernames: Collection
        A list of usernames to put into the WHERE condition.

    Returns
    -------
    df_sms: pd.DataFrame
        A dataframe of call data.
    """
    query_sms = (
        session.query(SMS, Participant.username)
        .filter(Participant.id == SMS.participant_id)
        .filter(Participant.username.in_(usernames))
    )
    with db_engine.connect() as connection:
        df_sms = pd.read_sql(query_sms.statement, connection)
    return df_sms


def enumerate_contacts(comm_df: pd.DataFrame) -> pd.DataFrame:
    """
    Count contacts (callers, senders) and enumerate them by their frequency.

    Parameters
    ----------
    comm_df: pd.DataFrame
        A dataframe of calls or SMSes.

    Returns
    -------
    comm_df: pd.DataFrame
        The altered dataframe with the column contact_id, arranged by frequency.
    """
    contact_counts = (
        comm_df.groupby(
            ["participant_id", "trace"]
        )  # We want to count rows by participant_id and trace
        .size()  # Count rows
        .reset_index()  # Make participant_id a regular column.
        .rename(columns={0: "freq"})
        .sort_values(["participant_id", "freq"], ascending=False)
        # First sort by participant_id and then by call frequency.
    )
    # We now have a frequency table of different traces (contacts) *within* each participant_id.
    # Next, enumerate these contacts.
    # In other words, recode the contacts into integers from 0 to n_contacts,
    # so that the first one is contacted the most often.
    contact_ids = (
        # Group again for enumeration.
        contact_counts.groupby("participant_id")
        .cumcount()  # Enumerate (count) rows *within* participants.
        .to_frame("contact_id")
    )
    contact_counts = contact_counts.join(contact_ids)
    # Add these contact_ids to the temporary (grouped) data frame.
    comm_df = comm_df.merge(contact_counts, on=["participant_id", "trace"])
    # Add these contact_ids to the original data frame.
    return comm_df


def count_comms(comm_df: pd.DataFrame) -> pd.DataFrame:
    """
    Calculate frequencies (and duration) of messages (or calls), grouped by their types.

    Parameters
    ----------
    comm_df: pd.DataFrame
        A dataframe of calls or SMSes.

    Returns
    -------
    comm_features: pd.DataFrame
        A list of communication features for every participant.
        These are:
        * the number of calls by type (incoming, outgoing missed) and in total,
        * the ratio of incoming and outgoing calls to the total number of calls,
        * the total and maximum duration of calls by type,
        * the number of messages by type (received, sent), and
        * the number of communication contacts by type. 
    """
    if "call_type" in comm_df:
        comm_counts = (
            comm_df.value_counts(subset=["participant_id", "call_type"])
            .unstack()
            .rename(columns=call_types)
            .add_prefix("no_")
        )
        # Count calls by type.
        comm_counts["no_all"] = comm_counts.sum(axis=1)
        # Add a total count of calls.
        comm_counts = comm_counts.assign(
            no_incoming_ratio=lambda x: x.no_incoming / x.no_all,
            no_outgoing_ratio=lambda x: x.no_outgoing / x.no_all,
        )
        # Ratio of incoming and outgoing calls to all calls.
        comm_duration_total = (
            comm_df.groupby(["participant_id", "call_type"])
            .sum()["call_duration"]
            .unstack()
            .rename(columns=call_types)
            .add_prefix("duration_total_")
        )
        # Total call duration by type.
        comm_duration_max = (
            comm_df.groupby(["participant_id", "call_type"])
            .max()["call_duration"]
            .unstack()
            .rename(columns=call_types)
            .add_prefix("duration_max_")
        )
        # Max call duration by type
        comm_contacts_counts = (
            enumerate_contacts(comm_df)
            .groupby(["participant_id"])
            .nunique()["contact_id"]
            .reset_index()
            .rename(columns={"contact_id": "no_contacts"})
        )
        # Number of communication contacts
        comm_features = comm_counts.join(comm_duration_total)
        comm_features = comm_features.join(comm_duration_max)
        comm_features = comm_features.merge(
            comm_contacts_counts,
            on="participant_id"
            ).set_index("participant_id")
        try:
            comm_features.drop(columns="duration_total_" + call_types[3], inplace=True)
            comm_features.drop(columns="duration_max_" + call_types[3], inplace=True)
        # The missed calls are always of 0 duration.
        except KeyError:
            pass
        # If there were no missed calls, this exception is raised.
        # But we are dropping the column anyway, so no need to deal with the exception.
    elif "message_type" in comm_df:
        comm_counts = (
            comm_df.value_counts(subset=["participant_id", "message_type"])
            .unstack()
            .rename(columns=sms_types)
            .add_prefix("no_")
        )
        comm_counts["no_all"] = comm_counts.sum(axis=1)
        # Add a total count of messages.
        comm_features = comm_counts.assign(
            no_received_ratio=lambda x: x.no_received / x.no_all,
            no_sent_ratio=lambda x: x.no_sent / x.no_all,
        )
        # Ratio of incoming and outgoing messages to all messages.
        comm_contacts_counts = (
            enumerate_contacts(comm_df)
            .groupby(["participant_id"])
            .nunique()["contact_id"]
            .reset_index()
            .rename(columns={"contact_id": "no_contacts"})
        )
        # Number of communication contacts
        comm_features = comm_features.merge(
            comm_contacts_counts,
            on="participant_id"
            ).set_index("participant_id")
    else:
        raise KeyError("The dataframe contains neither call_type or message_type")
    return comm_features


def contact_features(comm_df: pd.DataFrame) -> pd.DataFrame:
    """
    For each participant and for each of his contacts, this function
    counts the number of communications (by type) between them. If the
    argument passed is a dataframe with calls data, it additionally counts
    the total duration of calls between every pair (participant, contact).

    Parameters
    ----------
    df_enumerated: pd.DataFrame
        A dataframe of calls or SMSes.

    Returns
    -------
    comm_df: pd.DataFrame
        A new dataframe with a row for each pair (participant, contact).
    """
    df_enumerated = enumerate_contacts(comm_df)
    contacts_count = (
        df_enumerated
        .groupby(["participant_id","contact_id"])
        .size()
        .reset_index()
    )
    # Check whether df contains calls or SMS data since some
    # features we want to calculate are type-specyfic
    if "call_duration" in df_enumerated:
        # Add a column with the total duration of calls between two people
        duration_count = (
            df_enumerated
            .groupby(["participant_id", "contact_id"])
            # For each participant and for each caller, sum durations of their calls
            ["call_duration"]
            .sum()
            .reset_index()  # Make index (which is actually the participant id) a normal column
            .rename(columns={"call_duration": "total_call_duration"})
        )
        contacts_count = contacts_count.merge(duration_count, on=["participant_id", "contact_id"])
        contacts_count.rename(columns={0:"no_calls"}, inplace=True)
    else:
        contacts_count.rename(columns={0:"no_sms"}, inplace=True)
    # TODO:Determine work vs non-work contacts by work hours heuristics
    return contacts_count


def calls_sms_features(df_calls: pd.DataFrame, df_sms: pd.DataFrame) -> pd.DataFrame:
    """
    Calculates additional features relating calls and sms data.

    Parameters
    ----------
    df_calls: pd.DataFrame
        A dataframe of calls (return of get_call_data).
    df_sms: pd.DataFrame
        A dataframe of SMSes (return of get_sms_data).

    Returns
    -------
    df_calls_sms: pd.DataFrame
        The list of features relating calls and sms data for every participant.
        These are:
        * proportion_calls:
            proportion of calls in total number of communications
        * proportion_calls_incoming:
            proportion of incoming calls in total number of incoming/received communications
        * proportion_calls_outgoing:
            proportion of outgoing calls in total number of outgoing/sent communications
        * proportion_calls_missed_sms_received:
            proportion of missed calls to the number of received messages
        * proportion_calls_contacts:
            proportion of calls contacts in total number of communication contacts
    """
    count_calls = count_comms(df_calls)
    count_sms = count_comms(df_sms)
    count_joined = (
        count_calls.merge(
            count_sms, on="participant_id", suffixes=("_calls", "_sms")
        )  # Merge calls and sms features
        .reset_index()  # Make participant_id a regular column
        .assign(
            proportion_calls=(
                lambda x: x.no_all_calls / (x.no_all_calls + x.no_all_sms)
            ),
            proportion_calls_incoming=(
                lambda x: x.no_incoming / (x.no_incoming + x.no_received)
            ),
            proportion_calls_missed_sms_received=(
                lambda x: x.no_missed / (x.no_missed + x.no_received)
            ),
            proportion_calls_outgoing=(
                lambda x: x.no_outgoing / (x.no_outgoing + x.no_sent)
            ),
            proportion_calls_contacts=(
                lambda x: x.no_contacts_calls / (x.no_contacts_calls + x.no_contacts_sms)
            )
            # Calculate new features and create additional columns
        )[
            [
                "participant_id",
                "proportion_calls",
                "proportion_calls_incoming",
                "proportion_calls_outgoing",
                "proportion_calls_contacts",
                "proportion_calls_missed_sms_received",
            ]
        ]  # Filter out only the relevant features
    )
    return count_joined