from datetime import datetime, timezone
from app import db
from app.utils.encryption import encrypt_value, decrypt_value


def format_datetime(dt: datetime) -> str:
    """Format datetime to ISO format with UTC timezone indicator"""
    if dt is None:
        return None
    # If datetime is naive (no timezone), assume it's UTC
    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=timezone.utc)
    return dt.isoformat()


class AWSCredential(db.Model):
    """AWS Credential model for storing IAM Role or Access Key credentials"""
    __tablename__ = 'aws_credentials'
    
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), nullable=False)
    credential_type = db.Column(db.Enum('assume_role', 'access_key', name='credential_type'), nullable=False)
    account_id = db.Column(db.String(12), nullable=True, index=True)  # Make nullable for access_key type
    
    # For assume_role
    role_arn = db.Column(db.String(255))
    external_id = db.Column(db.String(255))
    
    # For access_key (encrypted)
    access_key_id = db.Column(db.String(255))
    secret_access_key_encrypted = db.Column(db.Text)
    
    created_at = db.Column(db.DateTime, default=datetime.utcnow)
    is_active = db.Column(db.Boolean, default=True)
    
    # Relationships
    users = db.relationship('UserCredential', back_populates='credential', cascade='all, delete-orphan')
    
    def set_secret_access_key(self, secret_key: str) -> None:
        """Encrypt and store the secret access key"""
        self.secret_access_key_encrypted = encrypt_value(secret_key)
    
    def get_secret_access_key(self) -> str:
        """Decrypt and return the secret access key"""
        if self.secret_access_key_encrypted:
            return decrypt_value(self.secret_access_key_encrypted)
        return None
    
    def to_dict(self, mask_sensitive: bool = True) -> dict:
        """Convert credential to dictionary"""
        result = {
            'id': self.id,
            'name': self.name,
            'credential_type': self.credential_type,
            'account_id': self.account_id,
            'role_arn': self.role_arn,
            'external_id': self.external_id,
            'access_key_id': self.access_key_id,
            'created_at': format_datetime(self.created_at),
            'is_active': self.is_active
        }
        
        # Mask sensitive data
        if mask_sensitive and self.access_key_id:
            result['access_key_id'] = self.access_key_id[:4] + '****' + self.access_key_id[-4:] if len(self.access_key_id) > 8 else '****'
        
        return result
    
    def __repr__(self):
        return f'<AWSCredential {self.name} ({self.account_id})>'


class UserCredential(db.Model):
    """Association table for User-Credential many-to-many relationship"""
    __tablename__ = 'user_credentials'
    
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
    credential_id = db.Column(db.Integer, db.ForeignKey('aws_credentials.id'), nullable=False)
    assigned_at = db.Column(db.DateTime, default=datetime.utcnow)
    
    # Relationships
    user = db.relationship('User', back_populates='credentials')
    credential = db.relationship('AWSCredential', back_populates='users')
    
    # Unique constraint to prevent duplicate assignments
    __table_args__ = (
        db.UniqueConstraint('user_id', 'credential_id', name='unique_user_credential'),
    )
    
    def __repr__(self):
        return f'<UserCredential user={self.user_id} credential={self.credential_id}>'


class BaseAssumeRoleConfig(db.Model):
    """Configuration for the base account used for Assume Role"""
    __tablename__ = 'base_assume_role_config'
    
    id = db.Column(db.Integer, primary_key=True)
    access_key_id = db.Column(db.String(255), nullable=False)
    secret_access_key_encrypted = db.Column(db.Text, nullable=False)
    updated_at = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
    
    def set_secret_access_key(self, secret_key: str) -> None:
        """Encrypt and store the secret access key"""
        self.secret_access_key_encrypted = encrypt_value(secret_key)
    
    def get_secret_access_key(self) -> str:
        """Decrypt and return the secret access key"""
        if self.secret_access_key_encrypted:
            return decrypt_value(self.secret_access_key_encrypted)
        return None
    
    def to_dict(self, mask_sensitive: bool = True) -> dict:
        """Convert config to dictionary"""
        result = {
            'id': self.id,
            'access_key_id': self.access_key_id,
            'updated_at': format_datetime(self.updated_at)
        }
        
        if mask_sensitive:
            result['access_key_id'] = self.access_key_id[:4] + '****' + self.access_key_id[-4:] if len(self.access_key_id) > 8 else '****'
        
        return result
    
    def __repr__(self):
        return f'<BaseAssumeRoleConfig id={self.id}>'