"""预设 BGM 库 — 免费可商用背景音乐清单.

按风格分类，存储在 OSS 或 CDN 上。
实际音频文件由运维统一上传，这里只维护元数据清单。
"""

from __future__ import annotations

from dataclasses import dataclass, field


@dataclass(frozen=True)
class PresetBGM:
    """预设 BGM 条目"""

    id: str
    name: str
    style: str  # 风格分类：upbeat/relax/tech/commerce/emotional/cinematic
    duration: float  # 时长（秒）
    artist: str = ""
    description: str = ""
    tags: list[str] = field(default_factory=list)
    audio_url: str = ""  # CDN/OSS 地址，空字符串表示待部署


# ── 预设库清单 ────────────────────────────────────────────────────────────────

PRESET_BGM_LIBRARY: list[PresetBGM] = [
    # 轻快 upbeat
    PresetBGM(
        id="bgm_upbeat_001",
        name="阳光清晨",
        style="upbeat",
        duration=120.0,
        artist="免费商用音乐库",
        description="轻快明亮的吉他+钢琴，适合vlog、生活记录",
        tags=["轻快", "阳光", "吉他", "vlog"],
    ),
    PresetBGM(
        id="bgm_upbeat_002",
        name="活力节拍",
        style="upbeat",
        duration=95.0,
        artist="免费商用音乐库",
        description="电子鼓点+合成器，节奏明快，适合运动、产品展示",
        tags=["轻快", "电子", "活力", "运动"],
    ),
    PresetBGM(
        id="bgm_upbeat_003",
        name="夏日漫步",
        style="upbeat",
        duration=110.0,
        artist="免费商用音乐库",
        description="Ukulele+口哨，轻松愉悦，适合旅行、美食",
        tags=["轻快", "夏日", "ukulele", "旅行"],
    ),
    # 治愈 relax
    PresetBGM(
        id="bgm_relax_001",
        name="静谧时光",
        style="relax",
        duration=180.0,
        artist="免费商用音乐库",
        description="温柔钢琴独奏，治愈系，适合读书、冥想",
        tags=["治愈", "钢琴", "安静", "冥想"],
    ),
    PresetBGM(
        id="bgm_relax_002",
        name="雨后森林",
        style="relax",
        duration=150.0,
        artist="免费商用音乐库",
        description="自然白噪音+轻柔吉他，放松减压",
        tags=["治愈", "自然", "放松", "环境音"],
    ),
    PresetBGM(
        id="bgm_relax_003",
        name="月光奏鸣曲",
        style="relax",
        duration=200.0,
        artist="古典音乐(公版)",
        description="贝多芬经典钢琴作品，公版免费",
        tags=["治愈", "古典", "钢琴", "优雅"],
    ),
    # 科技 tech
    PresetBGM(
        id="bgm_tech_001",
        name="未来科技",
        style="tech",
        duration=85.0,
        artist="免费商用音乐库",
        description="电子合成器+科技鼓点，适合数码产品、科技解说",
        tags=["科技", "电子", "未来感", "数码"],
    ),
    PresetBGM(
        id="bgm_tech_002",
        name="数据脉冲",
        style="tech",
        duration=100.0,
        artist="免费商用音乐库",
        description="极简电子节奏，适合数据分析、AI类视频",
        tags=["科技", "极简", "数据", "AI"],
    ),
    # 电商 commerce
    PresetBGM(
        id="bgm_commerce_001",
        name="心动时刻",
        style="commerce",
        duration=75.0,
        artist="免费商用音乐库",
        description="时尚动感节奏，适合商品展示、带货视频",
        tags=["电商", "时尚", "动感", "带货"],
    ),
    PresetBGM(
        id="bgm_commerce_002",
        name="品质生活",
        style="commerce",
        duration=90.0,
        artist="免费商用音乐库",
        description="高级感轻音乐，适合品牌宣传、高端产品",
        tags=["电商", "高端", "品牌", "品质"],
    ),
]

# ── 风格分类字典 ──────────────────────────────────────────────────────────────

BGM_STYLES: dict[str, str] = {
    "upbeat": "轻快",
    "relax": "治愈",
    "tech": "科技",
    "commerce": "电商",
    "emotional": "情感",
    "cinematic": "电影",
}


# ── 工具函数 ──────────────────────────────────────────────────────────────────


def get_preset_bgm(bgm_id: str) -> PresetBGM | None:
    """按 ID 获取预设 BGM。"""
    for bgm in PRESET_BGM_LIBRARY:
        if bgm.id == bgm_id:
            return bgm
    return None


def list_preset_bgm_by_style(style: str) -> list[PresetBGM]:
    """按风格筛选预设 BGM。"""
    return [bgm for bgm in PRESET_BGM_LIBRARY if bgm.style == style]


def search_preset_bgm(keyword: str) -> list[PresetBGM]:
    """按关键词搜索预设 BGM（名称+标签+描述）。"""
    kw = keyword.lower()
    results = []
    for bgm in PRESET_BGM_LIBRARY:
        if kw in bgm.name.lower() or kw in bgm.description.lower() or any(kw in tag.lower() for tag in bgm.tags):
            results.append(bgm)
    return results