from datetime import datetime
from app.extensions import db


class Resource(db.Model):
    __tablename__ = 'resources'

    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id', ondelete='CASCADE'),
                        nullable=False, index=True)
    title = db.Column(db.String(255), nullable=False)
    description = db.Column(db.Text, nullable=True)

    # 资源类型: text / image / audio / video
    resource_type = db.Column(db.Enum('text', 'image', 'audio', 'video'),
                              nullable=False, index=True)

    # 来源类型: upload / url / magnet
    source_type = db.Column(db.Enum('upload', 'url', 'magnet'),
                            nullable=False, default='upload')

    # 文件信息
    filename = db.Column(db.String(255), nullable=True)       # 磁盘上的文件名
    original_name = db.Column(db.String(255), nullable=True)  # 原始文件名
    file_path = db.Column(db.String(512), nullable=True)      # 相对于 static 的路径
    file_size = db.Column(db.BigInteger, nullable=True)       # 字节
    mime_type = db.Column(db.String(128), nullable=True)

    # 来源 URL / 磁力链
    source_url = db.Column(db.Text, nullable=True)

    # 下载状态: pending / downloading / done / failed (针对 url/magnet)
    download_status = db.Column(
        db.Enum('pending', 'downloading', 'done', 'failed', 'na'),
        nullable=False, default='na'
    )
    download_progress = db.Column(db.Integer, default=0)  # 0-100
    download_error = db.Column(db.Text, nullable=True)

    tags = db.Column(db.String(512), nullable=True)          # 逗号分隔
    is_public = db.Column(db.Boolean, default=False)

    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)
    updated_at = db.Column(db.DateTime, default=datetime.utcnow,
                           onupdate=datetime.utcnow, nullable=False)

    def __repr__(self):
        return f'<Resource {self.title}>'

    @property
    def size_human(self):
        """返回人性化的文件大小字符串"""
        if not self.file_size:
            return '未知'
        for unit in ['B', 'KB', 'MB', 'GB', 'TB']:
            if self.file_size < 1024:
                return f'{self.file_size:.1f} {unit}'
            self.file_size /= 1024
        return f'{self.file_size:.1f} PB'

    @property
    def tag_list(self):
        if not self.tags:
            return []
        return [t.strip() for t in self.tags.split(',') if t.strip()]

    @property
    def type_icon(self):
        icons = {
            'text': 'bi-file-text',
            'image': 'bi-image',
            'audio': 'bi-music-note-beamed',
            'video': 'bi-camera-video',
        }
        return icons.get(self.resource_type, 'bi-file')

    @property
    def type_badge_color(self):
        colors = {
            'text': 'secondary',
            'image': 'success',
            'audio': 'warning',
            'video': 'danger',
        }
        return colors.get(self.resource_type, 'secondary')