"""Встроенные шаблоны и генерация фонов."""
from __future__ import annotations

from pathlib import Path

from PIL import Image, ImageDraw

from .config import TEMPLATES_DIR

GOLD = (198, 158, 45)
NAVY = (27, 42, 74)
MAROON = (122, 31, 43)
CREAM = (255, 253, 247)

CLASSIC_PAGE = {"width": 1754, "height": 1240}   # A4 landscape @ ~150dpi
LETTER_PAGE = {"width": 1240, "height": 1754}    # A4 portrait  @ ~150dpi

# Меняйте при правке встроенных шаблонов — тогда они обновятся у пользователей.
BUILTIN_VERSION = "2"


def _diamond(d: ImageDraw.ImageDraw, cx: float, cy: float, r: float, fill) -> None:
    d.polygon([(cx, cy - r), (cx + r, cy), (cx, cy + r), (cx - r, cy)], fill=fill)


def _frame(img: Image.Image, outer: int = 34) -> ImageDraw.ImageDraw:
    W, H = img.size
    d = ImageDraw.Draw(img)
    d.rectangle([outer, outer, W - outer, H - outer], outline=GOLD, width=8)
    d.rectangle([outer + 24, outer + 24, W - outer - 24, H - outer - 24], outline=NAVY, width=2)
    d.rectangle([outer + 34, outer + 34, W - outer - 34, H - outer - 34], outline=GOLD, width=1)
    inset = outer + 24
    for cx, cy in [(inset, inset), (W - inset, inset), (inset, H - inset), (W - inset, H - inset)]:
        _diamond(d, cx, cy, 18, GOLD)
        _diamond(d, cx, cy, 8, NAVY)
        _diamond(d, cx, cy, 3, CREAM)
    return d


def draw_classic_bg(path: Path) -> None:
    W, H = CLASSIC_PAGE["width"], CLASSIC_PAGE["height"]
    img = Image.new("RGB", (W, H), CREAM)
    d = _frame(img)
    # разделитель под заголовком
    d.line([(W * 0.30, H * 0.245), (W * 0.70, H * 0.245)], fill=GOLD, width=3)
    _diamond(d, W * 0.5, H * 0.245, 9, GOLD)
    # линия для подписи
    d.line([(W * 0.42, H * 0.925), (W * 0.58, H * 0.925)], fill=NAVY, width=2)
    img.save(path, "PNG")


def draw_letter_bg(path: Path) -> None:
    W, H = LETTER_PAGE["width"], LETTER_PAGE["height"]
    img = Image.new("RGB", (W, H), CREAM)
    d = _frame(img)
    d.line([(W * 0.26, H * 0.205), (W * 0.74, H * 0.205)], fill=GOLD, width=3)
    _diamond(d, W * 0.5, H * 0.205, 9, GOLD)
    d.line([(W * 0.42, H * 0.925), (W * 0.58, H * 0.925)], fill=NAVY, width=2)
    img.save(path, "PNG")


def ensure_assets() -> None:
    """Создать фоны встроенных шаблонов, если их ещё нет."""
    builtin_dir = TEMPLATES_DIR / "builtin"
    builtin_dir.mkdir(parents=True, exist_ok=True)
    classic = builtin_dir / "classic.png"
    letter = builtin_dir / "letter.png"
    if not classic.exists():
        draw_classic_bg(classic)
    if not letter.exists():
        draw_letter_bg(letter)


def builtin_templates() -> list[dict]:
    return [
        {
            "slug": "classic",
            "title": "СЕРТИФИКАТ",
            "kind": "image",
            "background": "builtin/classic.png",
            "page": CLASSIC_PAGE,
            "defaults": {
                "title": "СЕРТИФИКАТ",
                "body": "за успешное прохождение программы",
            },
            "layout": [
                {"key": "title", "x": 0.5, "y": 0.175, "size": 96, "font": "serif-bold",
                 "color": "#1B2A4A", "align": "center", "uppercase": True,
                 "letter_spacing": 10, "max_width": 0.9},
                {"text": "настоящий сертификат подтверждает, что", "x": 0.5, "y": 0.315,
                 "size": 34, "font": "serif-italic", "color": "#5a5a5a", "align": "center"},
                {"key": "fio", "x": 0.5, "y": 0.435, "size": 96, "font": "serif-bold",
                 "color": "#7A1F2B", "align": "center", "max_width": 0.82},
                {"key": "body", "x": 0.5, "y": 0.645, "size": 40, "font": "serif",
                 "color": "#333333", "align": "center", "max_width": 0.72, "line_spacing": 1.45},
                {"text": "Дата выдачи", "x": 0.26, "y": 0.795, "size": 22, "font": "sans",
                 "color": "#8a8a8a", "align": "center"},
                {"key": "date", "x": 0.26, "y": 0.845, "size": 32, "font": "serif-bold",
                 "color": "#1B2A4A", "align": "center"},
                {"text": "Номер документа", "x": 0.74, "y": 0.795, "size": 22, "font": "sans",
                 "color": "#8a8a8a", "align": "center"},
                {"key": "number", "x": 0.74, "y": 0.845, "size": 32, "font": "serif-bold",
                 "color": "#1B2A4A", "align": "center"},
            ],
        },
        {
            "slug": "letter",
            "title": "БЛАГОДАРСТВЕННОЕ ПИСЬМО",
            "kind": "image",
            "background": "builtin/letter.png",
            "page": LETTER_PAGE,
            "defaults": {
                "title": "БЛАГОДАРСТВЕННОЕ ПИСЬМО",
                "body": "за вклад в развитие и активное участие",
            },
            "layout": [
                {"key": "title", "x": 0.5, "y": 0.15, "size": 62, "font": "serif-bold",
                 "color": "#1B2A4A", "align": "center", "uppercase": True,
                 "letter_spacing": 6, "max_width": 0.86},
                {"text": "объявляется благодарность", "x": 0.5, "y": 0.255, "size": 32,
                 "font": "serif-italic", "color": "#5a5a5a", "align": "center"},
                {"key": "fio", "x": 0.5, "y": 0.36, "size": 70, "font": "serif-bold",
                 "color": "#7A1F2B", "align": "center", "max_width": 0.84},
                {"key": "body", "x": 0.5, "y": 0.50, "size": 34, "font": "serif",
                 "color": "#333333", "align": "center", "max_width": 0.74, "line_spacing": 1.5},
                {"text": "Дата", "x": 0.27, "y": 0.80, "size": 22, "font": "sans",
                 "color": "#8a8a8a", "align": "center"},
                {"key": "date", "x": 0.27, "y": 0.85, "size": 30, "font": "serif-bold",
                 "color": "#1B2A4A", "align": "center"},
                {"text": "Номер", "x": 0.73, "y": 0.80, "size": 22, "font": "sans",
                 "color": "#8a8a8a", "align": "center"},
                {"key": "number", "x": 0.73, "y": 0.85, "size": 30, "font": "serif-bold",
                 "color": "#1B2A4A", "align": "center"},
            ],
        },
    ]