#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
生成文章模板与界面占位图资源。

项目原先依赖 uniCloud / 七牛的带签名外链图片，签名过期后全部 403，
导致首页与文章详情顶部出现空白。这里改为生成本地静态资源，
产物落在 static/template/ 下，无任何外部依赖。

用法: python tools/gen-template-assets.py
"""

import os
from PIL import Image, ImageDraw, ImageFont

ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
OUT_DIR = os.path.join(ROOT, "static", "template")

# 军旅主题配色：(名称, 顶部色, 底部色, 文字色)
THEMES = [
    ("default",   (193, 28, 31),  (92, 2, 1),    (255, 255, 255)),
    ("dark",      (34, 40, 49),   (17, 20, 24),  (235, 235, 235)),
    ("gold",      (176, 122, 40), (110, 71, 16), (255, 250, 235)),
    ("olive",     (74, 94, 58),   (40, 54, 32),  (240, 245, 235)),
    ("steel",     (86, 104, 122), (48, 61, 74),  (240, 244, 248)),
    ("light",     (250, 248, 245), (232, 226, 216), (58, 50, 44)),
]

W, H = 750, 480


def pick_font(size):
    """挑选一个可用的中文字体，找不到就退回默认字体。"""
    candidates = [
        r"C:\Windows\Fonts\msyh.ttc",
        r"C:\Windows\Fonts\msyhbd.ttc",
        r"C:\Windows\Fonts\simhei.ttf",
        r"C:\Windows\Fonts\simsun.ttc",
        "/System/Library/Fonts/PingFang.ttc",
        "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
    ]
    for path in candidates:
        if os.path.exists(path):
            try:
                return ImageFont.truetype(path, size)
            except Exception:
                continue
    return ImageFont.load_default()


def vertical_gradient(size, top, bottom):
    """竖直线性渐变。"""
    w, h = size
    img = Image.new("RGB", size)
    draw = ImageDraw.Draw(img)
    for y in range(h):
        t = y / max(1, h - 1)
        color = tuple(int(top[i] + (bottom[i] - top[i]) * t) for i in range(3))
        draw.line([(0, y), (w, y)], fill=color)
    return img


def add_decor(img, accent):
    """右下角加一点几何装饰，避免整块纯色显得像加载失败。"""
    w, h = img.size
    overlay = Image.new("RGBA", img.size, (0, 0, 0, 0))
    draw = ImageDraw.Draw(overlay)
    for i in range(6):
        radius = 120 + i * 70
        alpha = max(8, 42 - i * 6)
        draw.ellipse(
            [w - radius, h - radius, w + radius * 0.35, h + radius * 0.35],
            outline=(255, 255, 255, alpha),
            width=2,
        )
    draw.rectangle([0, h - 6, w, h], fill=accent + (90,))
    return Image.alpha_composite(img.convert("RGBA"), overlay).convert("RGB")


def build(name, top, bottom, text_color):
    img = vertical_gradient((W, H), top, bottom)
    img = add_decor(img, top)

    draw = ImageDraw.Draw(img)
    title_font = pick_font(64)
    sub_font = pick_font(28)

    title = "军歌嘹亮"
    sub = "军旅故事 · 老兵记忆"

    tw = draw.textlength(title, font=title_font)
    draw.text(((W - tw) / 2, H * 0.36), title, font=title_font, fill=text_color)

    sw = draw.textlength(sub, font=sub_font)
    draw.text(((W - sw) / 2, H * 0.36 + 92), sub, font=sub_font, fill=text_color)

    # 分隔线
    line_w = 120
    draw.line(
        [((W - line_w) / 2, H * 0.36 + 66), ((W + line_w) / 2, H * 0.36 + 66)],
        fill=text_color,
        width=2,
    )

    path = os.path.join(OUT_DIR, f"{name}.png")
    img.save(path, "PNG", optimize=True)
    return path


def build_placeholder_cover():
    """文章无封面时列表用的占位图。"""
    img = vertical_gradient((W, 420), (243, 241, 238), (226, 221, 214))
    draw = ImageDraw.Draw(img)
    font = pick_font(34)
    text = "暂无封面"
    tw = draw.textlength(text, font=font)
    draw.text(((W - tw) / 2, 190), text, font=font, fill=(160, 152, 144))
    path = os.path.join(OUT_DIR, "no-cover.png")
    img.save(path, "PNG", optimize=True)
    return path


def main():
    os.makedirs(OUT_DIR, exist_ok=True)
    made = []
    for name, top, bottom, text_color in THEMES:
        made.append(build(name, top, bottom, text_color))
    made.append(build_placeholder_cover())

    print(f"输出目录: {OUT_DIR}")
    for p in made:
        size = os.path.getsize(p)
        print(f"  {os.path.basename(p):<16} {size/1024:6.1f} KB")
    print(f"共 {len(made)} 个文件")


if __name__ == "__main__":
    main()