"""Paso 4: selección de sistemas habilitados.

Lee el catálogo maestro de sistemas y muestra checkboxes agrupados por categoría.
Pre-selecciona los sistemas marcados como `default_for` el VesselType del paso 1.
"""

from __future__ import annotations

from PySide6.QtWidgets import (
    QCheckBox,
    QFrame,
    QGridLayout,
    QGroupBox,
    QLabel,
    QPushButton,
    QScrollArea,
    QVBoxLayout,
    QWidget,
    QWizardPage,
)

from vmssailor.library import load_systems_catalog
from vmssailor.studio.theme import C_FOG, ui_font


class Step04Systems(QWizardPage):
    def __init__(self, parent: QWidget | None = None) -> None:
        super().__init__(parent)
        self.setTitle("Paso 4 · Sistemas instalados")
        self.setSubTitle(
            "Marca los sistemas que tendrá el buque. Esto define el menú lateral del Runtime y "
            "qué tags se generarán en sprints siguientes."
        )

        outer = QVBoxLayout(self)
        outer.setSpacing(10)

        header = QLabel(
            "Pre-selección automática según tipo de buque. Ajusta marcando/desmarcando."
        )
        header.setWordWrap(True)
        header.setStyleSheet(f"color: {C_FOG};")
        header.setFont(ui_font(10))
        outer.addWidget(header)

        # Buttons row
        btn_row = QGridLayout()
        self._btn_select_defaults = QPushButton("Resetear a defaults del tipo")
        self._btn_select_all = QPushButton("Marcar todos")
        self._btn_select_none = QPushButton("Desmarcar todos")
        btn_row.addWidget(self._btn_select_defaults, 0, 0)
        btn_row.addWidget(self._btn_select_all, 0, 1)
        btn_row.addWidget(self._btn_select_none, 0, 2)
        outer.addLayout(btn_row)

        self._btn_select_defaults.clicked.connect(self._select_defaults)
        self._btn_select_all.clicked.connect(self._select_all)
        self._btn_select_none.clicked.connect(self._select_none)

        # Scroll area with category groups
        scroll = QScrollArea()
        scroll.setWidgetResizable(True)
        scroll.setFrameShape(QFrame.Shape.NoFrame)
        outer.addWidget(scroll, 1)

        content = QWidget()
        self._content_layout = QVBoxLayout(content)
        self._content_layout.setSpacing(14)
        scroll.setWidget(content)

        # Build categories
        self._checkboxes: dict[str, QCheckBox] = {}
        self._catalog = self._load_catalog_safe()
        self._build_categories()

        # Register field
        from vmssailor.studio.wizard.wizard import F_SYSTEMS

        self.registerField(F_SYSTEMS, self, "enabled_systems", "systemsChanged")

    # ----- Property API ------------------------------------------------

    from PySide6.QtCore import Property, Signal

    systemsChanged = Signal()

    def get_enabled_systems(self) -> list[str]:
        return [sid for sid, cb in self._checkboxes.items() if cb.isChecked()]

    def set_enabled_systems(self, value: list[str]) -> None:
        for sid, cb in self._checkboxes.items():
            cb.setChecked(sid in value)
        self.systemsChanged.emit()

    enabled_systems = Property(
        list,
        fget=get_enabled_systems,
        fset=set_enabled_systems,
        notify=systemsChanged,
    )

    # ----- Internals ---------------------------------------------------

    def _load_catalog_safe(self) -> dict:
        try:
            return load_systems_catalog()
        except Exception:
            return {"categories": []}

    def _build_categories(self) -> None:
        for cat in self._catalog.get("categories", []):
            group = QGroupBox(cat.get("name", "—"))
            grid = QGridLayout(group)
            grid.setHorizontalSpacing(20)
            grid.setVerticalSpacing(6)
            for idx, sys in enumerate(cat.get("systems", [])):
                cb = QCheckBox(sys.get("name", sys["id"]))
                cb.setToolTip(f"id: {sys['id']}")
                cb.stateChanged.connect(self.systemsChanged.emit)
                self._checkboxes[sys["id"]] = cb
                grid.addWidget(cb, idx // 3, idx % 3)
            self._content_layout.addWidget(group)
        self._content_layout.addStretch(1)

    def _system_default_for(self, sys_id: str) -> list[str]:
        for cat in self._catalog.get("categories", []):
            for s in cat.get("systems", []):
                if s.get("id") == sys_id:
                    return s.get("default_for", [])
        return []

    def _select_defaults(self) -> None:
        from vmssailor.studio.wizard.wizard import F_VESSEL_TYPE

        v_type = self.field(F_VESSEL_TYPE)
        if not v_type:
            return
        for sid, cb in self._checkboxes.items():
            cb.setChecked(v_type in self._system_default_for(sid))

    def _select_all(self) -> None:
        for cb in self._checkboxes.values():
            cb.setChecked(True)

    def _select_none(self) -> None:
        for cb in self._checkboxes.values():
            cb.setChecked(False)

    def initializePage(self) -> None:
        # On first entry, pre-select defaults for the chosen vessel type.
        if not any(cb.isChecked() for cb in self._checkboxes.values()):
            self._select_defaults()