"""A deterministic daily selection of public-domain classical Chinese poetry."""

from datetime import datetime
from zoneinfo import ZoneInfo

# Original classical works; no modern copyrighted translations are included.
POEMS = [
    (
        "jing-ye-si",
        "静夜思",
        "李白",
        "床前明月光，疑是地上霜。\n举头望明月，低头思故乡。",
    ),
    (
        "chun-xiao",
        "春晓",
        "孟浩然",
        "春眠不觉晓，处处闻啼鸟。\n夜来风雨声，花落知多少。",
    ),
    (
        "deng-guan-que-lou",
        "登鹳雀楼",
        "王之涣",
        "白日依山尽，黄河入海流。\n欲穷千里目，更上一层楼。",
    ),
    ("xiang-si", "相思", "王维", "红豆生南国，春来发几枝。\n愿君多采撷，此物最相思。"),
    ("lu-zhai", "鹿柴", "王维", "空山不见人，但闻人语响。\n返景入深林，复照青苔上。"),
    (
        "zhu-li-guan",
        "竹里馆",
        "王维",
        "独坐幽篁里，弹琴复长啸。\n深林人不知，明月来相照。",
    ),
    (
        "jiang-xue",
        "江雪",
        "柳宗元",
        "千山鸟飞绝，万径人踪灭。\n孤舟蓑笠翁，独钓寒江雪。",
    ),
    (
        "xun-yin-zhe",
        "寻隐者不遇",
        "贾岛",
        "松下问童子，言师采药去。\n只在此山中，云深不知处。",
    ),
    (
        "min-nong",
        "悯农·其二",
        "李绅",
        "锄禾日当午，汗滴禾下土。\n谁知盘中餐，粒粒皆辛苦。",
    ),
    ("feng", "风", "李峤", "解落三秋叶，能开二月花。\n过江千尺浪，入竹万竿斜。"),
    (
        "wang-lu-shan",
        "望庐山瀑布",
        "李白",
        "日照香炉生紫烟，遥看瀑布挂前川。\n飞流直下三千尺，疑是银河落九天。",
    ),
    (
        "zao-fa-bai-di",
        "早发白帝城",
        "李白",
        "朝辞白帝彩云间，千里江陵一日还。\n两岸猿声啼不住，轻舟已过万重山。",
    ),
    (
        "wang-tian-men",
        "望天门山",
        "李白",
        "天门中断楚江开，碧水东流至此回。\n两岸青山相对出，孤帆一片日边来。",
    ),
    (
        "zeng-wang-lun",
        "赠汪伦",
        "李白",
        "李白乘舟将欲行，忽闻岸上踏歌声。\n桃花潭水深千尺，不及汪伦送我情。",
    ),
    (
        "shan-xing",
        "山行",
        "杜牧",
        "远上寒山石径斜，白云生处有人家。\n停车坐爱枫林晚，霜叶红于二月花。",
    ),
    (
        "jiang-nan-chun",
        "江南春",
        "杜牧",
        "千里莺啼绿映红，水村山郭酒旗风。\n南朝四百八十寺，多少楼台烟雨中。",
    ),
    (
        "ti-xi-lin-bi",
        "题西林壁",
        "苏轼",
        "横看成岭侧成峰，远近高低各不同。\n不识庐山真面目，只缘身在此山中。",
    ),
    (
        "hui-xiang-ou-shu",
        "回乡偶书·其一",
        "贺知章",
        "少小离家老大回，乡音无改鬓毛衰。\n儿童相见不相识，笑问客从何处来。",
    ),
    (
        "ye-yu-ji-bei",
        "夜雨寄北",
        "李商隐",
        "君问归期未有期，巴山夜雨涨秋池。\n何当共剪西窗烛，却话巴山夜雨时。",
    ),
    (
        "feng-qiao",
        "枫桥夜泊",
        "张继",
        "月落乌啼霜满天，江枫渔火对愁眠。\n姑苏城外寒山寺，夜半钟声到客船。",
    ),
]


def catalog():
    return [
        {
            "id": p[0],
            "title": p[1],
            "author": p[2],
            "lines": p[3],
            "source": "Public-domain classical Chinese poetry",
            "edition": "frame-flow-classics-v1",
        }
        for p in POEMS
    ]


def get_poem(date=None, poem_id=None):
    day = (
        datetime.strptime(date, "%Y-%m-%d").date()
        if date
        else datetime.now(ZoneInfo("Asia/Shanghai")).date()
    )
    poems = catalog()
    if poem_id:
        selected = next((p for p in poems if p["id"] == poem_id), None)
        if selected is None:
            raise ValueError("Unknown poem")
    else:
        selected = poems[day.toordinal() % len(poems)]
    return {**selected, "date": day.isoformat()}