"""把榜单画成品牌化 PNG，供「一键导出发微信群」。仅依赖 Pillow。

绘图与数据解耦：调用方传入已排好序的 boards（每个榜单 = 标题 + 行列表），
本模块只负责排版渲染，不碰数据库。
"""
from __future__ import annotations

import io
import os
from typing import Optional

from PIL import Image, ImageDraw, ImageFont

from .config import WWW_DIR

# 品牌色（取自队徽：藏青 / 金 / 红）
NAVY_DEEP = (10, 23, 48)
NAVY = (17, 37, 74)
PANEL = (24, 48, 92)
GOLD = (212, 175, 55)
GOLD2 = (235, 203, 107)
CREAM = (242, 236, 221)
BLUE = (61, 165, 217)
MUTED = (157, 176, 208)
LINE = (40, 70, 120)

# 候选 CJK 字体（Windows / Linux）
_FONT_DIRS = [r"C:\Windows\Fonts", "/usr/share/fonts", os.path.expanduser("~/.fonts")]
_FONT_FILES = [
    "msyhbd.ttc", "msyh.ttc", "msyh.ttf", "simhei.ttf", "simsun.ttc",
    "NotoSansCJK-Regular.ttc", "NotoSansSC-Regular.otf", "DengXian.ttf",
]


def _font_path() -> Optional[str]:
    for d in _FONT_DIRS:
        for name in _FONT_FILES:
            p = os.path.join(d, name)
            if os.path.exists(p):
                return p
    return None


_FONT_PATH = _font_path()


def _font(size: int) -> ImageFont.FreeTypeFont:
    if _FONT_PATH:
        try:
            return ImageFont.truetype(_FONT_PATH, size)
        except OSError:
            pass
    return ImageFont.load_default()


def _crest(size: int) -> Optional[Image.Image]:
    """加载队徽并裁成圆形；失败则返回 None（不阻断导出）。"""
    path = WWW_DIR / "crest.jpg"
    if not path.exists():
        return None
    try:
        im = Image.open(path).convert("RGBA").resize((size, size))
        mask = Image.new("L", (size, size), 0)
        ImageDraw.Draw(mask).ellipse((0, 0, size, size), fill=255)
        im.putalpha(mask)
        return im
    except Exception:
        return None


def render_leaderboard_png(
    team_name: str,
    season_label: str,
    date_str: str,
    boards: list[tuple[str, list[tuple[str, str, str]]]],
) -> bytes:
    """渲染榜单 PNG。

    boards: [(标题, [(名次, 名字, 数值), ...]), ...]，建议 4 个榜单（2×2 网格）。
    返回 PNG 字节流。
    """
    W = 920
    margin = 40
    header_h = 132
    col_gap = 28
    row_title_h = 46
    line_h = 34
    max_rows = 8

    col_w = (W - margin * 2 - col_gap) // 2
    rows_per_board = min(
        max_rows, max((len(rows) for _, rows in boards), default=0)
    )
    board_h = row_title_h + line_h * max(1, rows_per_board) + 16
    n_board_rows = (len(boards) + 1) // 2
    H = header_h + n_board_rows * (board_h + col_gap) + margin

    img = Image.new("RGB", (W, H), NAVY_DEEP)
    d = ImageDraw.Draw(img)

    f_team = _font(40)
    f_sub = _font(18)
    f_btitle = _font(22)
    f_row = _font(20)
    f_rank = _font(20)

    # ---- 顶部渐变带 + 队名 ----
    d.rectangle((0, 0, W, header_h), fill=NAVY)
    d.line((0, header_h, W, header_h), fill=GOLD, width=2)
    x_text = margin
    crest = _crest(84)
    if crest is not None:
        img.paste(crest, (margin, 24), crest)
        x_text = margin + 84 + 20
    d.text((x_text, 30), team_name, font=f_team, fill=GOLD2)
    d.text((x_text + 2, 84), f"{season_label} · 榜单 · {date_str}", font=f_sub, fill=MUTED)

    # ---- 2×2 榜单 ----
    medals = {1: "①", 2: "②", 3: "③"}
    for idx, (title, rows) in enumerate(boards):
        r, c = divmod(idx, 2)
        x = margin + c * (col_w + col_gap)
        y = header_h + col_gap + r * (board_h + col_gap)
        # 卡片底
        d.rounded_rectangle((x, y, x + col_w, y + board_h), radius=16, fill=NAVY)
        d.rounded_rectangle(
            (x, y, x + col_w, y + board_h), radius=16, outline=LINE, width=1
        )
        # 标题
        d.text((x + 18, y + 12), title, font=f_btitle, fill=GOLD2)
        d.line((x + 18, y + 44, x + col_w - 18, y + 44), fill=LINE, width=1)
        # 行
        ry = y + row_title_h + 6
        if not rows:
            d.text((x + 18, ry), "暂无数据", font=f_row, fill=MUTED)
        for rank, name, value in rows[:max_rows]:
            rk = medals.get(int(rank) if rank.isdigit() else 0, rank)
            rk_color = GOLD if rank in ("1", "2", "3") else MUTED
            d.text((x + 18, ry), rk, font=f_rank, fill=rk_color)
            d.text((x + 56, ry), name, font=f_row, fill=CREAM)
            vw = d.textlength(value, font=f_row)
            d.text((x + col_w - 18 - vw, ry), value, font=f_row, fill=GOLD2)
            ry += line_h

    buf = io.BytesIO()
    img.save(buf, format="PNG")
    return buf.getvalue()