from datetime import datetime
from werkzeug.security import generate_password_hash, check_password_hash
from flask_login import UserMixin
from app import db, login_manager
import uuid

@login_manager.user_loader
def load_user(id):
    return User.query.get(int(id))

class User(UserMixin, db.Model):
    __tablename__ = 'user'
    
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(64), index=True, unique=True)
    email = db.Column(db.String(120), index=True, unique=True)
    password_hash = db.Column(db.String(128))
    created_at = db.Column(db.DateTime, default=datetime.utcnow)
    last_login = db.Column(db.DateTime)
    
    # Relationships
    files = db.relationship('File', backref='owner', lazy='dynamic', 
                           foreign_keys='File.user_id', cascade='all, delete-orphan')
    shares = db.relationship('Share', backref='owner', lazy='dynamic',
                            foreign_keys='Share.user_id', cascade='all, delete-orphan')
    downloads = db.relationship('Download', backref='user', lazy='dynamic',
                                foreign_keys='Download.user_id', cascade='all, delete-orphan')
    
    def __repr__(self):
        return f'<User {self.username}>'
    
    def set_password(self, password):
        self.password_hash = generate_password_hash(password)
    
    def check_password(self, password):
        return check_password_hash(self.password_hash, password)

class File(db.Model):
    __tablename__ = 'file'
    
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(255), nullable=False)
    storage_name = db.Column(db.String(255))  # Used for storing files with unique names
    is_folder = db.Column(db.Boolean, default=False)
    mime_type = db.Column(db.String(128))
    size = db.Column(db.Integer, default=0)  # Size in bytes
    parent_id = db.Column(db.Integer, db.ForeignKey('file.id', ondelete='CASCADE'), nullable=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)
    updated_at = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
    
    # Relationships
    children = db.relationship('File', backref=db.backref('parent', remote_side=[id]),
                              lazy='dynamic', cascade='all, delete-orphan')
    shares = db.relationship('Share', backref='file', lazy='dynamic', cascade='all, delete-orphan')
    downloads = db.relationship('Download', backref='file', lazy='dynamic', cascade='all, delete-orphan')
    
    def __repr__(self):
        return f'<File {self.name} {"(Folder)" if self.is_folder else ""}>'
    
    def generate_storage_name(self):
        """Generate a unique name for file storage to prevent conflicts"""
        if self.is_folder:
            return None
        
        # Generate a unique filename using UUID
        ext = self.name.rsplit('.', 1)[1].lower() if '.' in self.name else ''
        return f"{uuid.uuid4().hex}.{ext}" if ext else f"{uuid.uuid4().hex}"

class Share(db.Model):
    __tablename__ = 'share'
    
    id = db.Column(db.Integer, primary_key=True)
    file_id = db.Column(db.Integer, db.ForeignKey('file.id', ondelete='CASCADE'), nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
    share_token = db.Column(db.String(64), unique=True)
    is_public = db.Column(db.Boolean, default=False)
    is_password_protected = db.Column(db.Boolean, default=False)
    password_hash = db.Column(db.String(128))
    expiry_date = db.Column(db.DateTime, nullable=True)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)
    
    def __repr__(self):
        return f'<Share {self.share_token}>'
    
    def set_password(self, password):
        self.password_hash = generate_password_hash(password)
        self.is_password_protected = True
    
    def check_password(self, password):
        return check_password_hash(self.password_hash, password)
    
    def generate_token(self):
        """Generate a unique token for sharing"""
        return uuid.uuid4().hex

class Download(db.Model):
    __tablename__ = 'download'
    
    id = db.Column(db.Integer, primary_key=True)
    file_id = db.Column(db.Integer, db.ForeignKey('file.id', ondelete='CASCADE'), nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=True)  # Nullable for anonymous downloads
    ip_address = db.Column(db.String(64))
    user_agent = db.Column(db.String(255))
    share_id = db.Column(db.Integer, db.ForeignKey('share.id', ondelete='SET NULL'), nullable=True)
    downloaded_at = db.Column(db.DateTime, default=datetime.utcnow)
    
    def __repr__(self):
        return f'<Download of File {self.file_id} at {self.downloaded_at}>'