"""Themes de l'application : palette d'interface (QSS) + palette du terminal.

Trois themes sont fournis (clair par defaut, bleu nuit, noir). Ils partagent le meme
gabarit `resources/theme.qss`, dont les $variables sont remplacees par la palette
choisie : une seule feuille de style a maintenir au lieu de trois quasi identiques.
"""
from __future__ import annotations

from string import Template

from PySide6.QtCore import Qt
from PySide6.QtGui import QColor, QFont, QIcon, QLinearGradient, QPainter, QPixmap
from PySide6.QtWidgets import QApplication

from app.app_settings import get_setting, set_setting
from app.paths import RESOURCES_DIR  # noqa: E402  (chemins valables aussi en .exe)

STYLESHEET_PATH = RESOURCES_DIR / "theme.qss"

THEME_LIGHT = "light"
THEME_MIDNIGHT = "midnight"
THEME_BLACK = "black"
DEFAULT_THEME = THEME_LIGHT

# ---------------------------------------------------------------------------
# Palettes d'interface
# ---------------------------------------------------------------------------
UI_PALETTES: dict[str, dict[str, str]] = {
    THEME_LIGHT: {
        "window": "#f4f6f9", "base": "#ffffff", "panel": "#eef1f6", "elevated": "#e4e9f0",
        "input": "#ffffff", "hover": "#dfe6f2", "pressed": "#d2dae8",
        "border": "#d3dae4", "border_strong": "#b9c3d1",
        "text": "#1c2430", "text_dim": "#5c6875", "text_disabled": "#a3adba",
        "accent": "#2f6fed", "accent_hover": "#1f5ed6", "on_accent": "#ffffff",
        "scroll": "#c3ccd9", "scroll_hover": "#a7b3c4",
    },
    THEME_MIDNIGHT: {
        "window": "#0a1220", "base": "#0c1526", "panel": "#0e1a30", "elevated": "#1c2c47",
        "input": "#101c30", "hover": "#172542", "pressed": "#16233b",
        "border": "#1c2c47", "border_strong": "#2a3c5c",
        "text": "#e6ecf6", "text_dim": "#93a4c2", "text_disabled": "#55627c",
        "accent": "#2f6fed", "accent_hover": "#4f8cff", "on_accent": "#ffffff",
        "scroll": "#2a3c5c", "scroll_hover": "#3a527d",
    },
    THEME_BLACK: {
        "window": "#000000", "base": "#0a0a0a", "panel": "#141414", "elevated": "#1f1f1f",
        "input": "#141414", "hover": "#262626", "pressed": "#0f0f0f",
        "border": "#2b2b2b", "border_strong": "#3d3d3d",
        "text": "#e8e8e8", "text_dim": "#9a9a9a", "text_disabled": "#5a5a5a",
        "accent": "#4a9eff", "accent_hover": "#6fb3ff", "on_accent": "#000000",
        "scroll": "#3a3a3a", "scroll_hover": "#525252",
    },
}

# ---------------------------------------------------------------------------
# Palettes du terminal (16 couleurs ANSI + defauts + curseur)
# ---------------------------------------------------------------------------
TERMINAL_PALETTES: dict[str, dict] = {
    THEME_LIGHT: {
        "fg": "#1c2430", "bg": "#ffffff", "cursor": (47, 111, 237, 110),
        "selection": (47, 111, 237, 70),
        "ansi": {
            "black": "#1c2430", "red": "#c0392b", "green": "#2e7d32", "brown": "#a06800",
            "blue": "#1f5ed6", "magenta": "#8e24aa", "cyan": "#00838f", "white": "#5c6875",
            "brightblack": "#8a94a3", "brightred": "#e04b3a", "brightgreen": "#3ca142",
            "brightbrown": "#c98a00", "brightblue": "#2f6fed", "brightmagenta": "#a944c7",
            "brightcyan": "#0aa2b0", "brightwhite": "#1c2430",
        },
    },
    THEME_MIDNIGHT: {
        "fg": "#e6ecf6", "bg": "#0b1220", "cursor": (79, 140, 255, 140),
        "selection": (79, 140, 255, 90),
        "ansi": {
            "black": "#0b1220", "red": "#ff6b81", "green": "#8ce99a", "brown": "#f2c94c",
            "blue": "#4f8cff", "magenta": "#c792ea", "cyan": "#63d4e0", "white": "#dbe4f5",
            "brightblack": "#3a4a68", "brightred": "#ff8a9b", "brightgreen": "#a9e6b5",
            "brightbrown": "#f5d778", "brightblue": "#7aa9ff", "brightmagenta": "#dcb3f0",
            "brightcyan": "#8fe3ec", "brightwhite": "#ffffff",
        },
    },
    THEME_BLACK: {
        "fg": "#e8e8e8", "bg": "#000000", "cursor": (74, 158, 255, 140),
        "selection": (74, 158, 255, 90),
        "ansi": {
            "black": "#000000", "red": "#e05561", "green": "#8cc265", "brown": "#d18f52",
            "blue": "#4aa5f0", "magenta": "#c162de", "cyan": "#42b3c2", "white": "#d0d0d0",
            "brightblack": "#5a5a5a", "brightred": "#ff6b78", "brightgreen": "#a5e075",
            "brightbrown": "#e5a663", "brightblue": "#6fb3ff", "brightmagenta": "#d178ee",
            "brightcyan": "#5fc9d8", "brightwhite": "#ffffff",
        },
    },
}

THEME_LABELS = {
    THEME_LIGHT: "Clair",
    THEME_MIDNIGHT: "Bleu nuit",
    THEME_BLACK: "Noir",
}

_current_theme = DEFAULT_THEME


# ---------------------------------------------------------------------------
# Preference persistante
# ---------------------------------------------------------------------------
def load_saved_theme() -> str:
    theme = get_setting("theme")
    return theme if theme in UI_PALETTES else DEFAULT_THEME


def save_theme(theme: str) -> None:
    set_setting("theme", theme)


DEFAULT_FONT_SIZE = 10


def load_font_size() -> int:
    try:
        size = int(get_setting("font_size", DEFAULT_FONT_SIZE))
    except (TypeError, ValueError):
        return DEFAULT_FONT_SIZE
    return size if 6 <= size <= 32 else DEFAULT_FONT_SIZE


def save_font_size(size: int) -> None:
    set_setting("font_size", size)


def current_theme() -> str:
    return _current_theme


def terminal_palette(theme: str | None = None) -> dict:
    return TERMINAL_PALETTES.get(theme or _current_theme, TERMINAL_PALETTES[DEFAULT_THEME])


# ---------------------------------------------------------------------------
# Application du theme
# ---------------------------------------------------------------------------
def apply_theme(app: QApplication, theme: str = DEFAULT_THEME) -> None:
    """Bascule sur le style Fusion (necessaire pour que la QSS s'applique
    uniformement, y compris aux widgets stylises nativement par Windows) puis
    construit la feuille de style a partir de la palette demandee."""
    global _current_theme
    if theme not in UI_PALETTES:
        theme = DEFAULT_THEME
    _current_theme = theme

    app.setStyle("Fusion")
    try:
        template = Template(STYLESHEET_PATH.read_text(encoding="utf-8"))
        app.setStyleSheet(template.safe_substitute(UI_PALETTES[theme]))
    except OSError:
        pass


def build_app_icon() -> QIcon:
    """Genere une icone simple (pas de fichier externe requis) : carre + prompt '>_'"""
    size = 64
    pixmap = QPixmap(size, size)
    pixmap.fill(Qt.transparent)

    painter = QPainter(pixmap)
    painter.setRenderHint(QPainter.Antialiasing)

    gradient = QLinearGradient(0, 0, size, size)
    gradient.setColorAt(0, QColor("#182a4a"))
    gradient.setColorAt(1, QColor("#0a1220"))
    painter.setBrush(gradient)
    painter.setPen(QColor("#2a3c5c"))
    painter.drawRoundedRect(2, 2, size - 4, size - 4, 14, 14)

    font = QFont("Consolas")
    font.setBold(True)
    font.setPointSize(24)
    painter.setFont(font)
    painter.setPen(QColor("#4f8cff"))
    painter.drawText(pixmap.rect(), Qt.AlignCenter, ">_")

    painter.end()
    return QIcon(pixmap)