"""Sidebar dinámico de sistemas del proyecto.

Lee el catálogo maestro de sistemas y muestra:
- Sistemas habilitados del Project (en la parte superior, con contador de equipos)
- Sistemas NO habilitados pero disponibles (al pie, en gris)

En Sprint 1 es sólo visualización. En Sprint 2 se podrá toggle desde aquí.
"""

from __future__ import annotations

from collections import Counter

from PySide6.QtCore import Qt, Signal
from PySide6.QtWidgets import (
    QFrame,
    QLabel,
    QListWidget,
    QListWidgetItem,
    QVBoxLayout,
    QWidget,
)

from vmssailor.core.enums import SystemId
from vmssailor.core.project import Project
from vmssailor.library import load_systems_catalog
from vmssailor.studio.theme import C_FOG, ui_font


class SystemSidebar(QWidget):
    """Lista lateral de sistemas. Emite `systemActivated(SystemId)` al doble-click."""

    systemActivated = Signal(str)

    def __init__(self, parent: QWidget | None = None) -> None:
        super().__init__(parent)
        self._project: Project | None = None
        self._catalog = self._load_catalog_safe()

        layout = QVBoxLayout(self)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(0)

        # Header section: wizard / overview
        self._wizard_label = QLabel("WIZARD")
        self._wizard_label.setObjectName("overline")
        self._wizard_label.setFont(ui_font(9))
        self._wizard_label.setStyleSheet(
            f"color: {C_FOG}; padding: 16px 16px 6px 16px; letter-spacing: 2px;"
        )
        layout.addWidget(self._wizard_label)

        self._wizard_steps = QListWidget()
        self._wizard_steps.setFrameShape(QFrame.Shape.NoFrame)
        for step in self._WIZARD_STEPS:
            item = QListWidgetItem(step)
            item.setFlags(item.flags() & ~Qt.ItemIsSelectable)
            self._wizard_steps.addItem(item)
        self._wizard_steps.setFixedHeight(self._wizard_steps.sizeHintForRow(0) * 8 + 10)
        layout.addWidget(self._wizard_steps)

        # Systems section
        self._systems_header = QLabel("SISTEMAS HABILITADOS")
        self._systems_header.setObjectName("overline")
        self._systems_header.setFont(ui_font(9))
        self._systems_header.setStyleSheet(
            f"color: {C_FOG}; padding: 16px 16px 6px 16px; letter-spacing: 2px;"
        )
        layout.addWidget(self._systems_header)

        self._enabled_list = QListWidget()
        self._enabled_list.setFrameShape(QFrame.Shape.NoFrame)
        self._enabled_list.itemDoubleClicked.connect(self._on_double_click_enabled)
        layout.addWidget(self._enabled_list, 1)

        self._available_header = QLabel("DISPONIBLES (NO HABILITADOS)")
        self._available_header.setObjectName("overline")
        self._available_header.setFont(ui_font(9))
        self._available_header.setStyleSheet(
            f"color: {C_FOG}; padding: 16px 16px 6px 16px; letter-spacing: 2px;"
        )
        layout.addWidget(self._available_header)

        self._available_list = QListWidget()
        self._available_list.setFrameShape(QFrame.Shape.NoFrame)
        self._available_list.setMaximumHeight(140)
        layout.addWidget(self._available_list)

        self.refresh()

    # ----- Const -----------------------------------------------------

    _WIZARD_STEPS = (
        "1 · Tipo de buque",
        "2 · Plantilla",
        "3 · Dimensiones",
        "4 · Sistemas",
        "5 · Equipos sugeridos",
        "6 · Refinamiento",
        "7 · Topología I/O",
        "8 · Confirmación",
    )

    # ----- Public ----------------------------------------------------

    def set_project(self, project: Project | None) -> None:
        self._project = project
        self.refresh()

    def refresh(self) -> None:
        self._enabled_list.clear()
        self._available_list.clear()

        if self._project is None:
            self._systems_header.setText("SISTEMAS HABILITADOS · sin proyecto")
            self._enabled_list.addItem("(crea o abre un proyecto)")
            return

        enabled = set(self._project.systems_enabled)
        equipment_count: Counter[str] = Counter()
        for eq in self._project.equipment:
            equipment_count[eq.system_id.value] += 1

        self._systems_header.setText(
            f"SISTEMAS HABILITADOS · {len(enabled)}"
        )

        for sys_id_str in sorted(s.value for s in enabled):
            name = self._system_display_name(sys_id_str)
            count = equipment_count.get(sys_id_str, 0)
            label = f"{name}    ·  {count} eq" if count else f"{name}    ·  —"
            item = QListWidgetItem(label)
            item.setData(Qt.UserRole, sys_id_str)
            self._enabled_list.addItem(item)

        all_known = {s.value for s in SystemId}
        disabled = sorted(all_known - {s.value for s in enabled})
        self._available_header.setText(
            f"DISPONIBLES (NO HABILITADOS) · {len(disabled)}"
        )
        for sys_id_str in disabled[:40]:
            item = QListWidgetItem(self._system_display_name(sys_id_str))
            item.setForeground(Qt.GlobalColor.darkGray)
            item.setData(Qt.UserRole, sys_id_str)
            self._available_list.addItem(item)

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

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

    def _system_display_name(self, sys_id_value: str) -> str:
        for cat in self._catalog.get("categories", []):
            for s in cat.get("systems", []):
                if s.get("id") == sys_id_value:
                    return s.get("name", sys_id_value)
        return sys_id_value.replace("_", " ").title()

    def _on_double_click_enabled(self, item: QListWidgetItem) -> None:
        sys_id = item.data(Qt.UserRole)
        if sys_id:
            self.systemActivated.emit(sys_id)