from django import forms
from django.db import transaction
from django.db.models import OuterRef, Subquery

from common.components import (
    SearchSelect,
    SearchSelectOption,
    searchselect_selected,
)
from games.models import (
    Device,
    Game,
    GameStatusChange,
    Platform,
    PlayEvent,
    Purchase,
    Session,
)

custom_date_widget = forms.DateInput(attrs={"type": "date"})
custom_datetime_widget = forms.DateTimeInput(
    attrs={"type": "datetime-local"}, format="%Y-%m-%d %H:%M"
)
autofocus_input_widget = forms.TextInput(attrs={"autofocus": "autofocus"})


class MultipleGameChoiceField(forms.ModelMultipleChoiceField):
    def label_from_instance(self, obj) -> str:
        return obj.search_label


class SingleGameChoiceField(forms.ModelChoiceField):
    def label_from_instance(self, obj) -> str:
        return obj.search_label


def _game_options(values) -> list[SearchSelectOption]:
    """Resolve game ids (or instances) to SearchSelectOptions via one pk__in query."""
    return [
        {
            "value": g.id,
            "label": g.search_label,
            "data": {"platform": g.platform_id or ""},
        }
        for g in Game.objects.filter(pk__in=values).select_related("platform")
    ]


def _device_options(values) -> list[SearchSelectOption]:
    return [
        {"value": d.id, "label": d.name, "data": {}}
        for d in Device.objects.filter(pk__in=values)
    ]


def _platform_options(values) -> list[SearchSelectOption]:
    return [
        {"value": p.id, "label": p.name, "data": {}}
        for p in Platform.objects.filter(pk__in=values)
    ]


class SearchSelectWidget(forms.Widget):
    """Thin Django adapter that renders a `SearchSelect()` component.

    The only place that knows about Django/forms — the component itself stays
    reusable outside forms.
    """

    def __init__(
        self,
        *,
        search_url,
        options_resolver,
        multi_select=False,
        items_visible=5,
        items_scroll=10,
        always_visible=False,
        placeholder="Search…",
        attrs=None,
    ):
        super().__init__(attrs)
        self.search_url = search_url
        self.options_resolver = options_resolver
        self.multi_select = multi_select
        self.items_visible = items_visible
        self.items_scroll = items_scroll
        self.always_visible = always_visible
        self.placeholder = placeholder

    @staticmethod
    def _values(value) -> list:
        if value is None:
            return []
        if isinstance(value, (list, tuple)):
            return [v for v in value if v not in (None, "")]
        return [value] if value not in (None, "") else []

    def render(self, name, value, attrs=None, renderer=None):
        selected = searchselect_selected(self._values(value), self.options_resolver)
        autofocus = bool((attrs or {}).get("autofocus"))
        return SearchSelect(
            name=name,
            selected=selected,
            options=None,
            search_url=self.search_url,
            multi_select=self.multi_select,
            items_visible=self.items_visible,
            items_scroll=self.items_scroll,
            always_visible=self.always_visible,
            placeholder=self.placeholder,
            id=(attrs or {}).get("id", ""),
            autofocus=autofocus,
        )

    def value_from_datadict(self, data, files, name):
        return data.get(name)


class SearchSelectMultiple(SearchSelectWidget):
    def value_from_datadict(self, data, files, name):
        if hasattr(data, "getlist"):
            return data.getlist(name)
        return data.get(name)


class SessionForm(forms.ModelForm):
    game = SingleGameChoiceField(
        queryset=Game.objects.order_by("sort_name"),
        widget=SearchSelectWidget(
            search_url="/api/games/search", options_resolver=_game_options
        ),
    )

    duration_manual = forms.DurationField(
        required=False,
        widget=forms.TextInput(
            attrs={"x-mask": "99:99:99", "placeholder": "HH:MM:SS", "x-data": ""}
        ),
        label="Manual duration",
    )
    device = forms.ModelChoiceField(
        queryset=Device.objects.order_by("name"),
        required=False,
        widget=SearchSelectWidget(
            search_url="/api/devices/search", options_resolver=_device_options
        ),
    )

    mark_as_played = forms.BooleanField(
        required=False,
        initial={"mark_as_played": True},
        label="Set game status to Played if Unplayed",
    )

    class Meta:
        widgets = {
            "timestamp_start": custom_datetime_widget,
            "timestamp_end": custom_datetime_widget,
        }
        model = Session
        fields = [
            "game",
            "timestamp_start",
            "timestamp_end",
            "duration_manual",
            "emulated",
            "device",
            "note",
            "mark_as_played",
        ]

    def save(self, commit=True):
        session = super().save(commit=False)
        if self.cleaned_data.get("mark_as_played"):
            game_instance = session.game
            if game_instance.status == "u":
                game_instance.status = "p"
            if commit:
                game_instance.save()
        if commit:
            session.save()
        return session


def related_purchase_queryset():
    """GAME purchases annotated with their first game's name.

    Rendering the ``related_purchase`` ``<select>`` calls ``str()`` on every
    option, and ``Purchase.__str__`` falls back to ``first_game`` — one extra
    query per option (700+ on a large library). Annotating the first game's
    name via a subquery lets the choice field build labels without those
    per-row queries.
    """
    first_game_name = Subquery(
        Game.objects.filter(purchases=OuterRef("pk")).order_by("id").values("name")[:1]
    )
    return Purchase.objects.filter(type=Purchase.GAME).annotate(
        _first_game_name=first_game_name
    )


class RelatedPurchaseChoiceField(forms.ModelChoiceField):
    def label_from_instance(self, obj) -> str:
        # Mirrors Purchase.standardized_name but reads the annotated first-game
        # name instead of querying first_game per option.
        name = obj.name or getattr(obj, "_first_game_name", None)
        return name or obj.standardized_name


class PurchaseForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["platform"].queryset = Platform.objects.order_by("name")

    games = MultipleGameChoiceField(
        queryset=Game.objects.order_by("sort_name"),
        widget=SearchSelectMultiple(
            search_url="/api/games/search",
            options_resolver=_game_options,
            multi_select=True,
        ),
    )
    platform = forms.ModelChoiceField(
        queryset=Platform.objects.order_by("name"),
        widget=SearchSelectWidget(
            search_url="/api/platforms/search", options_resolver=_platform_options
        ),
    )
    related_purchase = RelatedPurchaseChoiceField(
        queryset=related_purchase_queryset(),
        required=False,
    )

    price_currency = forms.CharField(
        widget=forms.TextInput(
            attrs={
                "x-mask": "aaa",
                "placeholder": "CZK",
                "x-data": "",
                "class": "uppercase",
            }
        ),
        label="Currency",
    )

    class Meta:
        widgets = {
            "date_purchased": custom_date_widget,
            "date_refunded": custom_date_widget,
        }
        model = Purchase
        fields = [
            "games",
            "platform",
            "date_purchased",
            "date_refunded",
            "infinite",
            "price",
            "price_currency",
            "ownership_type",
            "type",
            "related_purchase",
            "name",
        ]

    def clean(self):
        cleaned_data = super().clean()
        purchase_type = cleaned_data.get("type")
        related_purchase = cleaned_data.get("related_purchase")
        name = cleaned_data.get("name")

        # Set the type on the instance to use get_type_display()
        # This is safe because we're not saving the instance.
        self.instance.type = purchase_type

        if purchase_type != Purchase.GAME:
            type_display = self.instance.get_type_display()
            if not related_purchase:
                self.add_error(
                    "related_purchase",
                    f"{type_display} must have a related purchase.",
                )
            if not name:
                self.add_error("name", f"{type_display} must have a name.")
        return cleaned_data


class IncludeNameSelect(forms.Select):
    def create_option(self, name, value, *args, **kwargs):
        option = super().create_option(name, value, *args, **kwargs)
        if value:
            option["attrs"]["data-name"] = value.instance.name
            option["attrs"]["data-year"] = value.instance.year_released
        return option


class GameModelChoiceField(forms.ModelChoiceField):
    def label_from_instance(self, obj):
        # Use sort_name as the label for the option
        return obj.sort_name


class GameForm(forms.ModelForm):
    platform = forms.ModelChoiceField(
        queryset=Platform.objects.order_by("name"),
        required=False,
        widget=SearchSelectWidget(
            search_url="/api/platforms/search", options_resolver=_platform_options
        ),
    )

    class Meta:
        model = Game
        fields = [
            "name",
            "sort_name",
            "platform",
            "original_year_released",
            "year_released",
            "status",
            "mastered",
            "wikidata",
        ]
        widgets = {"name": autofocus_input_widget}


class PlatformForm(forms.ModelForm):
    class Meta:
        model = Platform
        fields = [
            "name",
            "icon",
            "group",
        ]
        widgets = {"name": autofocus_input_widget}


class DeviceForm(forms.ModelForm):
    class Meta:
        model = Device
        fields = ["name", "type"]
        widgets = {"name": autofocus_input_widget}


class PlayEventForm(forms.ModelForm):
    game = SingleGameChoiceField(
        queryset=Game.objects.order_by("sort_name"),
        widget=SearchSelectWidget(
            search_url="/api/games/search",
            options_resolver=_game_options,
            attrs={"autofocus": "autofocus"},
        ),
    )

    mark_as_finished = forms.BooleanField(
        required=False,
        initial={"mark_as_finished": True},
        label="Set game status to Finished",
    )

    class Meta:
        model = PlayEvent
        fields = ["game", "started", "ended", "note", "mark_as_finished"]
        widgets = {
            "started": custom_date_widget,
            "ended": custom_date_widget,
        }

    def save(self, commit=True):
        with transaction.atomic():
            session = super().save(commit=False)
            if self.cleaned_data.get("mark_as_finished"):
                game_instance = session.game
                game_instance.status = "f"
                game_instance.save()
            session.save()
        return session


class GameStatusChangeForm(forms.ModelForm):
    class Meta:
        model = GameStatusChange
        fields = [
            "game",
            "old_status",
            "new_status",
            "timestamp",
        ]
        widgets = {
            "timestamp": custom_datetime_widget,
        }