# app/utils/theme_manager.py
"""
Theme Manager
=============
Centralizza la gestione del tema dell'applicazione.
Elimina hard-coded styles e fornisce stylesheet generati dal config.yaml.

Features:
- Genera QSS (Qt StyleSheet) dal config.yaml
- Fornisce utility per colori e font del tema
- Supporta theme switching (light/dark future)
- Validazione del theme config
- Caching degli stylesheet generati
"""

import yaml
from pathlib import Path
from typing import Dict, Any, Optional
from loguru import logger


class ThemeManager:
    """
    Gestore centralizzato del tema dell'applicazione.

    Usage:
        theme_mgr = ThemeManager()
        stylesheet = theme_mgr.get_main_stylesheet()
        app.setStyleSheet(stylesheet)

        # Oppure per widget specifici
        button_style = theme_mgr.get_button_stylesheet()
        btn.setStyleSheet(button_style)
    """

    def __init__(self, config_path: Optional[Path] = None):
        """
        Inizializza il ThemeManager.

        Args:
            config_path: Path al config.yaml. Se None, usa il default.
        """
        self.config_path = config_path or self._get_default_config_path()
        self.theme_config = self._load_theme_config()
        self._stylesheet_cache = {}

        logger.info(f"ThemeManager inizializzato con tema: {self.theme_config.get('name', 'Default')}")

    def _get_default_config_path(self) -> Path:
        """Ritorna il path di default al config.yaml"""
        return Path(__file__).parent.parent / "config" / "config.yaml"

    def _load_theme_config(self) -> Dict[str, Any]:
        """Carica la configurazione del tema dal YAML"""
        try:
            with open(self.config_path, 'r', encoding='utf-8') as f:
                full_config = yaml.safe_load(f)

            theme = full_config.get('theme', {})

            # Validazione base
            if not theme:
                logger.warning("Nessun tema trovato nel config.yaml, uso defaults")
                return self._get_default_theme()

            return theme

        except Exception as e:
            logger.error(f"Errore caricamento theme config: {e}", exc_info=True)
            return self._get_default_theme()

    def _get_default_theme(self) -> Dict[str, Any]:
        """Ritorna un tema di fallback con valori Microsoft-style"""
        return {
            'primary_color': '#0078D4',
            'background_primary': '#FFFFFF',
            'background_panel': '#F3F2F1',
            'text_primary': '#323130',
            'text_secondary': '#605E5C',
            'border_color': '#EDEBE9',
            'border_dark': '#D2D0CE',
            'fonts': {
                'system': 'Segoe UI',
                'primary_size': 12,
                'small_size': 11,
                'large_size': 14
            },
            'spacing': {
                'sm': 8,
                'md': 12,
                'lg': 16
            }
        }

    # ========== GETTER UTILITIES ==========

    def get_color(self, key: str, default: str = '#000000') -> str:
        """
        Ottiene un colore dal tema.

        Args:
            key: Chiave del colore (es. 'primary_color', 'text_primary')
            default: Colore di fallback se la chiave non esiste

        Returns:
            Stringa colore in formato hex (#RRGGBB)
        """
        return self.theme_config.get(key, default)

    def get_font_family(self) -> str:
        """Ottiene il font family principale"""
        fonts = self.theme_config.get('fonts', {})
        return fonts.get('system', 'Segoe UI')

    def get_font_size(self, size_key: str = 'primary_size') -> int:
        """
        Ottiene una dimensione font dal tema.

        Args:
            size_key: Chiave della dimensione (primary_size, small_size, large_size, etc.)

        Returns:
            Dimensione in px
        """
        fonts = self.theme_config.get('fonts', {})
        return fonts.get(size_key, 12)

    def get_spacing(self, size_key: str = 'md') -> int:
        """
        Ottiene uno spacing dal tema.

        Args:
            size_key: Chiave dello spacing (xs, sm, md, lg, xl)

        Returns:
            Spacing in px
        """
        spacing = self.theme_config.get('spacing', {})
        return spacing.get(size_key, 12)

    # ========== STYLESHEET GENERATORS ==========

    def get_main_stylesheet(self) -> str:
        """
        Genera il main application stylesheet.
        Sostituisce gli hard-coded styles sparsi nel codice.

        Returns:
            QSS completo per l'applicazione
        """
        if 'main' in self._stylesheet_cache:
            return self._stylesheet_cache['main']

        qss = f"""
/* ========================================
   MyICR Suite - Main Application Stylesheet
   Generated by ThemeManager
   ======================================== */

/* === GLOBAL DEFAULTS === */
QWidget {{
    font-family: {self.get_font_family()};
    font-size: {self.get_font_size('primary_size')}px;
    color: {self.get_color('text_primary')};
    background-color: {self.get_color('background_primary')};
}}

QMainWindow {{
    background-color: {self.get_color('background_panel')};
}}

/* === BUTTONS === */
QPushButton {{
    background-color: {self.get_color('background_secondary', '#FAFAFA')};
    border: 1px solid {self.get_color('border_color')};
    border-radius: 2px;
    padding: {self.get_spacing('sm')}px {self.get_spacing('md')}px;
    color: {self.get_color('text_primary')};
    min-height: 24px;
}}

QPushButton:hover {{
    background-color: {self.get_color('background_hover', '#F3F2F1')};
    border: 1px solid {self.get_color('primary_color')};
}}

QPushButton:pressed {{
    background-color: {self.get_color('primary_pressed', '#005A9E')};
    color: white;
}}

QPushButton:disabled {{
    background-color: {self.get_color('background_panel')};
    color: {self.get_color('text_light', '#8A8886')};
    border: 1px solid {self.get_color('border_color')};
}}

/* === PRIMARY BUTTON (Accent) === */
QPushButton[primary="true"] {{
    background-color: {self.get_color('primary_color')};
    color: white;
    border: 1px solid {self.get_color('primary_color')};
    font-weight: 500;
}}

QPushButton[primary="true"]:hover {{
    background-color: {self.get_color('primary_hover', '#106EBE')};
}}

QPushButton[primary="true"]:pressed {{
    background-color: {self.get_color('primary_pressed')};
}}

/* === COMBO BOX === */
QComboBox {{
    background-color: white;
    border: 1px solid {self.get_color('border_color')};
    border-radius: 2px;
    padding: 4px 8px;
    min-height: 24px;
}}

QComboBox:hover {{
    border: 1px solid {self.get_color('primary_color')};
}}

QComboBox::drop-down {{
    border: none;
    width: 20px;
}}

QComboBox QAbstractItemView {{
    background-color: white;
    border: 1px solid {self.get_color('border_dark')};
    selection-background-color: {self.get_color('primary_light', '#DEECF9')};
    selection-color: {self.get_color('text_primary')};
}}

/* === LINE EDIT === */
QLineEdit, QTextEdit, QPlainTextEdit {{
    background-color: white;
    border: 1px solid {self.get_color('border_color')};
    border-radius: 2px;
    padding: 4px 8px;
    selection-background-color: {self.get_color('primary_light')};
}}

QLineEdit:focus, QTextEdit:focus {{
    border: 1px solid {self.get_color('primary_color')};
    border-bottom: 2px solid {self.get_color('primary_color')};
}}

/* === LABELS === */
QLabel {{
    background-color: transparent;
    color: {self.get_color('text_primary')};
}}

QLabel[heading="true"] {{
    font-size: {self.get_font_size('large_size')}px;
    font-weight: 600;
    color: {self.get_color('text_primary')};
}}

QLabel[secondary="true"] {{
    color: {self.get_color('text_secondary')};
}}

/* === FRAMES / PANELS === */
QFrame[panel="true"] {{
    background-color: white;
    border: 1px solid {self.get_color('border_color')};
    border-radius: 2px;
}}

/* === MENU BAR === */
QMenuBar {{
    background-color: {self.get_color('background_panel')};
    border-bottom: 1px solid {self.get_color('border_dark')};
    spacing: 4px;
    padding: 2px;
}}

QMenuBar::item {{
    background-color: transparent;
    padding: 4px 12px;
    border-radius: 2px;
}}

QMenuBar::item:selected {{
    background-color: {self.get_color('background_hover')};
}}

QMenuBar::item:pressed {{
    background-color: {self.get_color('primary_light')};
}}

/* === MENU === */
QMenu {{
    background-color: white;
    border: 1px solid {self.get_color('border_dark')};
    padding: 4px;
}}

QMenu::item {{
    padding: 6px 24px;
    border-radius: 2px;
}}

QMenu::item:selected {{
    background-color: {self.get_color('primary_light')};
}}

/* === STATUS BAR === */
QStatusBar {{
    background-color: {self.get_color('background_panel')};
    border-top: 1px solid {self.get_color('border_dark')};
    color: {self.get_color('text_secondary')};
    padding: {self.get_spacing('sm')}px;
}}

/* === TABLE WIDGET === */
QTableWidget {{
    background-color: white;
    border: 1px solid {self.get_color('border_color')};
    gridline-color: {self.get_color('border_color')};
    selection-background-color: {self.get_color('primary_light')};
    selection-color: {self.get_color('text_primary')};
}}

QTableWidget::item {{
    padding: 4px;
    border: none;
}}

QTableWidget::item:hover {{
    background-color: {self.get_color('background_hover')};
}}

QHeaderView::section {{
    background-color: {self.get_color('background_panel')};
    color: {self.get_color('text_primary')};
    border: none;
    border-right: 1px solid {self.get_color('border_color')};
    border-bottom: 1px solid {self.get_color('border_dark')};
    padding: 6px;
    font-weight: 600;
}}

QHeaderView::section:hover {{
    background-color: {self.get_color('background_hover')};
}}

/* === SCROLLBAR === */
QScrollBar:vertical {{
    background-color: {self.get_color('background_panel')};
    width: 12px;
    border: none;
}}

QScrollBar::handle:vertical {{
    background-color: {self.get_color('border_dark')};
    min-height: 30px;
    border-radius: 6px;
    margin: 2px;
}}

QScrollBar::handle:vertical:hover {{
    background-color: {self.get_color('secondary_color', '#605E5C')};
}}

QScrollBar::add-line:vertical, QScrollBar::sub-line:vertical {{
    height: 0px;
}}

QScrollBar:horizontal {{
    background-color: {self.get_color('background_panel')};
    height: 12px;
    border: none;
}}

QScrollBar::handle:horizontal {{
    background-color: {self.get_color('border_dark')};
    min-width: 30px;
    border-radius: 6px;
    margin: 2px;
}}

QScrollBar::handle:horizontal:hover {{
    background-color: {self.get_color('secondary_color')};
}}

/* === TAB WIDGET === */
QTabWidget::pane {{
    border: 1px solid {self.get_color('border_color')};
    border-top: none;
    background-color: white;
}}

QTabBar::tab {{
    background-color: {self.get_color('background_panel')};
    border: 1px solid {self.get_color('border_color')};
    border-bottom: none;
    padding: 6px 16px;
    margin-right: 2px;
}}

QTabBar::tab:selected {{
    background-color: white;
    border-bottom: 2px solid {self.get_color('primary_color')};
}}

QTabBar::tab:hover {{
    background-color: {self.get_color('background_hover')};
}}

/* === TOOLTIPS === */
QToolTip {{
    background-color: {self.get_color('text_primary')};
    color: white;
    border: none;
    padding: 4px 8px;
    border-radius: 2px;
    font-size: {self.get_font_size('small_size')}px;
}}
"""

        self._stylesheet_cache['main'] = qss
        return qss

    def get_button_stylesheet(self, is_primary: bool = False) -> str:
        """
        Genera stylesheet per un bottone singolo.

        Args:
            is_primary: Se True, genera stile accent button

        Returns:
            QSS per QPushButton
        """
        if is_primary:
            return f"""
                QPushButton {{
                    background-color: {self.get_color('primary_color')};
                    color: white;
                    border: 1px solid {self.get_color('primary_color')};
                    border-radius: 2px;
                    padding: {self.get_spacing('sm')}px {self.get_spacing('md')}px;
                    font-weight: 500;
                    min-height: 28px;
                }}
                QPushButton:hover {{
                    background-color: {self.get_color('primary_hover')};
                }}
                QPushButton:pressed {{
                    background-color: {self.get_color('primary_pressed')};
                }}
                QPushButton:disabled {{
                    background-color: {self.get_color('border_color')};
                    color: {self.get_color('text_light')};
                }}
            """
        else:
            return f"""
                QPushButton {{
                    background-color: {self.get_color('background_secondary')};
                    border: 1px solid {self.get_color('border_color')};
                    border-radius: 2px;
                    padding: {self.get_spacing('sm')}px {self.get_spacing('md')}px;
                    color: {self.get_color('text_primary')};
                    min-height: 28px;
                }}
                QPushButton:hover {{
                    background-color: {self.get_color('background_hover')};
                    border: 1px solid {self.get_color('primary_color')};
                }}
                QPushButton:pressed {{
                    background-color: {self.get_color('primary_light')};
                }}
                QPushButton:disabled {{
                    background-color: {self.get_color('background_panel')};
                    color: {self.get_color('text_light')};
                }}
            """

    def get_panel_stylesheet(self, with_border: bool = True) -> str:
        """
        Genera stylesheet per un panel/frame.

        Args:
            with_border: Se True, include bordo

        Returns:
            QSS per QFrame
        """
        border_style = f"border: 1px solid {self.get_color('border_color')};" if with_border else "border: none;"

        return f"""
            QFrame {{
                background-color: white;
                {border_style}
                border-radius: 2px;
            }}
        """

    def clear_cache(self):
        """Pulisce la cache degli stylesheet (utile per theme switching)"""
        self._stylesheet_cache.clear()
        logger.info("Theme stylesheet cache cleared")

    def reload_theme(self):
        """Ricarica il tema dal config.yaml"""
        self.theme_config = self._load_theme_config()
        self.clear_cache()
        logger.info("Theme config reloaded")


# ========== SINGLETON INSTANCE ==========

_theme_manager_instance: Optional[ThemeManager] = None


def get_theme_manager() -> ThemeManager:
    """
    Ottiene l'istanza singleton del ThemeManager.

    Returns:
        ThemeManager instance
    """
    global _theme_manager_instance
    if _theme_manager_instance is None:
        _theme_manager_instance = ThemeManager()
    return _theme_manager_instance