from rest_framework import serializers

from apps.api.serializers.slack_channel import SlackChannelSerializer
from apps.api.serializers.user_group import UserGroupSerializer
from apps.schedules.constants import SCHEDULE_CHECK_NEXT_DAYS
from apps.schedules.models import OnCallSchedule
from apps.schedules.tasks import (
    check_gaps_and_empty_shifts_in_schedule,
    schedule_notify_about_empty_shifts_in_schedule,
    schedule_notify_about_gaps_in_schedule,
)
from common.api_helpers.custom_fields import TeamPrimaryKeyRelatedField
from common.api_helpers.mixins import EagerLoadingMixin
from common.api_helpers.utils import CurrentOrganizationDefault


class ScheduleBaseSerializer(EagerLoadingMixin, serializers.ModelSerializer):
    id = serializers.CharField(read_only=True, source="public_primary_key")
    organization = serializers.HiddenField(default=CurrentOrganizationDefault())
    team = TeamPrimaryKeyRelatedField(allow_null=True, required=False)
    slack_channel = SlackChannelSerializer(read_only=True)
    user_group = UserGroupSerializer()
    warnings = serializers.SerializerMethodField()
    on_call_now = serializers.SerializerMethodField()
    number_of_escalation_chains = serializers.SerializerMethodField()
    enable_web_overrides = serializers.SerializerMethodField()

    class Meta:
        fields = [
            "id",
            "organization",
            "team",
            "name",
            "user_group",
            "warnings",
            "on_call_now",
            "has_gaps",
            "notify_oncall_shift_freq",
            "notify_empty_oncall",
            "mention_oncall_start",
            "mention_oncall_next",
            "number_of_escalation_chains",
            "enable_web_overrides",
        ]

    SELECT_RELATED = ["organization", "team", "user_group", "slack_channel"]

    CANT_UPDATE_USER_GROUP_WARNING = (
        "Cannot update the user group, make sure to grant user group modification rights to "
        "non-admin users in Slack workspace settings"
    )
    SCHEDULE_HAS_GAPS_WARNING = f"Schedule has unassigned time periods during next {SCHEDULE_CHECK_NEXT_DAYS} days"
    SCHEDULE_HAS_EMPTY_SHIFTS_WARNING = f"Schedule has empty shifts during next {SCHEDULE_CHECK_NEXT_DAYS} days"

    def get_warnings(self, obj):
        can_update_user_groups = self.context.get("can_update_user_groups", False)
        warnings = []
        if obj.user_group and not can_update_user_groups:
            warnings.append(self.CANT_UPDATE_USER_GROUP_WARNING)
        if obj.has_gaps:
            warnings.append(self.SCHEDULE_HAS_GAPS_WARNING)
        if obj.has_empty_shifts:
            warnings.append(self.SCHEDULE_HAS_EMPTY_SHIFTS_WARNING)
        return warnings

    def get_on_call_now(self, obj):
        # Serializer context is set here: apps.api.views.schedule.ScheduleView.get_serializer_context
        users = self.context["oncall_users"].get(obj, [])
        organization = self.context["request"].auth.organization
        return [user.short(organization) for user in users]

    def get_number_of_escalation_chains(self, obj):
        # num_escalation_chains param added in queryset via annotate. Check ScheduleView.get_queryset
        # return 0 for just created schedules
        num = getattr(obj, "num_escalation_chains", 0)
        return num or 0

    def get_enable_web_overrides(self, obj):
        return False

    def validate(self, attrs):
        if "slack_channel_id" in attrs:
            # this is set in the serializer classes which subclass ScheduleBaseSerializer
            attrs["slack_channel"] = attrs.pop("slack_channel_id", None)
        return attrs

    def create(self, validated_data):
        created_schedule = super().create(validated_data)
        check_gaps_and_empty_shifts_in_schedule.apply_async((created_schedule.pk,))
        schedule_notify_about_empty_shifts_in_schedule.apply_async((created_schedule.pk,))
        schedule_notify_about_gaps_in_schedule.apply_async((created_schedule.pk,))
        return created_schedule


class ScheduleFastSerializer(serializers.ModelSerializer):
    id = serializers.CharField(read_only=True, source="public_primary_key")

    class Meta:
        model = OnCallSchedule
        fields = [
            "id",
            "name",
        ]