"""
AWS Credentials Management API endpoints

Provides credential CRUD operations and validation.
Requirements: 2.1, 2.4, 2.6, 2.7
"""
from flask import jsonify, request, g
from app import db
from app.api import api_bp
from app.models import AWSCredential, UserCredential, BaseAssumeRoleConfig
from app.services import login_required, admin_required, get_current_user_from_context, get_accessible_credentials
from app.errors import ValidationError, NotFoundError
from app.scanners.credentials import AWSCredentialProvider, CredentialError


def validate_account_id(account_id: str) -> bool:
    """Validate AWS account ID format (12 digits)"""
    if not account_id:
        return False
    return len(account_id) == 12 and account_id.isdigit()


def validate_role_arn(role_arn: str) -> bool:
    """Validate AWS Role ARN format"""
    if not role_arn:
        return False
    # Basic ARN format: arn:aws:iam::account-id:role/role-name
    return role_arn.startswith('arn:aws:iam::') and ':role/' in role_arn


@api_bp.route('/credentials', methods=['GET'])
@login_required
def get_credentials():
    """
    Get credentials list with pagination (sensitive info masked)
    
    Query params:
        page: Page number (default: 1)
        page_size: Items per page (default: 20, max: 100)
    
    Returns:
        {
            "data": [credential objects with masked sensitive data],
            "pagination": {...}
        }
    """
    # Get pagination parameters
    page = request.args.get('page', 1, type=int)
    # Support both pageSize (frontend) and page_size (backend convention)
    page_size = request.args.get('pageSize', type=int) or request.args.get('page_size', type=int) or 20
    
    # Validate pagination parameters
    if page < 1:
        page = 1
    if page_size < 1:
        page_size = 20
    if page_size > 100:
        page_size = 100
    
    # Get current user
    current_user = get_current_user_from_context()
    
    # Get accessible credentials based on user role
    query = get_accessible_credentials(current_user)
    
    # Order by created_at descending
    query = query.order_by(AWSCredential.created_at.desc())
    
    # Get total count
    total = query.count()
    
    # Calculate total pages
    total_pages = (total + page_size - 1) // page_size if total > 0 else 1
    
    # Apply pagination
    credentials = query.offset((page - 1) * page_size).limit(page_size).all()
    
    return jsonify({
        'data': [cred.to_dict(mask_sensitive=True) for cred in credentials],
        'pagination': {
            'page': page,
            'page_size': page_size,
            'total': total,
            'total_pages': total_pages
        }
    }), 200


@api_bp.route('/credentials/create', methods=['POST'])
@admin_required
def create_credential():
    """
    Create a new AWS credential
    
    Request body:
        {
            "name": "string" (required),
            "credential_type": "assume_role" | "access_key" (required),
            "account_id": "string" (required, 12 digits),
            "role_arn": "string" (required for assume_role),
            "external_id": "string" (optional for assume_role),
            "access_key_id": "string" (required for access_key),
            "secret_access_key": "string" (required for access_key)
        }
    
    Returns:
        { credential object }
    """
    data = request.get_json()
    
    if not data:
        raise ValidationError(
            message="Request body is required",
            details={"reason": "missing_body"}
        )
    
    # Validate required fields
    required_fields = ['name', 'credential_type']
    if data.get('credential_type') == 'assume_role':
        required_fields.append('account_id')
    
    missing_fields = [field for field in required_fields if not data.get(field)]
    
    if missing_fields:
        raise ValidationError(
            message="Missing required fields",
            details={"missing_fields": missing_fields}
        )
    
    name = data['name'].strip()
    credential_type = data['credential_type']
    account_id = data.get('account_id', '').strip() if data.get('account_id') else None
    
    # Validate name length
    if len(name) < 1 or len(name) > 100:
        raise ValidationError(
            message="Name must be between 1 and 100 characters",
            details={"field": "name", "reason": "invalid_length"}
        )
    
    # Validate credential type
    if credential_type not in ['assume_role', 'access_key']:
        raise ValidationError(
            message="Invalid credential type. Must be 'assume_role' or 'access_key'",
            details={"field": "credential_type", "reason": "invalid_value"}
        )
    
    # Validate account ID (only required for assume_role)
    if credential_type == 'assume_role':
        if not account_id or not validate_account_id(account_id):
            raise ValidationError(
                message="Invalid AWS account ID. Must be 12 digits",
                details={"field": "account_id", "reason": "invalid_format"}
            )
    
    # Validate type-specific fields
    if credential_type == 'assume_role':
        role_arn = data.get('role_arn', '').strip()
        if not role_arn:
            raise ValidationError(
                message="Role ARN is required for assume_role credential type",
                details={"missing_fields": ["role_arn"]}
            )
        if not validate_role_arn(role_arn):
            raise ValidationError(
                message="Invalid Role ARN format",
                details={"field": "role_arn", "reason": "invalid_format"}
            )
    else:  # access_key
        access_key_id = data.get('access_key_id', '').strip()
        secret_access_key = data.get('secret_access_key', '').strip()
        
        if not access_key_id:
            raise ValidationError(
                message="Access Key ID is required for access_key credential type",
                details={"missing_fields": ["access_key_id"]}
            )
        if not secret_access_key:
            raise ValidationError(
                message="Secret Access Key is required for access_key credential type",
                details={"missing_fields": ["secret_access_key"]}
            )
    
    # Create credential
    credential = AWSCredential(
        name=name,
        credential_type=credential_type,
        account_id=account_id,  # Will be None for access_key initially
        is_active=True
    )
    
    if credential_type == 'assume_role':
        credential.role_arn = data.get('role_arn', '').strip()
        credential.external_id = data.get('external_id', '').strip() or None
    else:
        access_key_id = data.get('access_key_id', '').strip()
        secret_access_key = data.get('secret_access_key', '').strip()
        
        credential.access_key_id = access_key_id
        credential.set_secret_access_key(secret_access_key)
        
        # Auto-detect account ID for access_key type
        if not account_id:
            try:
                provider = AWSCredentialProvider(
                    credential_type='access_key',
                    credential_config={
                        'access_key_id': access_key_id,
                        'secret_access_key': secret_access_key
                    }
                )
                provider.validate()
                detected_account_id = provider.get_account_id()
                credential.account_id = detected_account_id
            except Exception as e:
                raise ValidationError(
                    message=f"Failed to validate Access Key credentials: {str(e)}",
                    details={"reason": "credential_validation_failed"}
                )
    
    db.session.add(credential)
    db.session.commit()
    
    return jsonify(credential.to_dict(mask_sensitive=True)), 201


@api_bp.route('/credentials/update', methods=['POST'])
@admin_required
def update_credential():
    """
    Update an existing AWS credential
    
    Request body:
        {
            "id": number (required),
            "name": "string" (optional),
            "account_id": "string" (optional),
            "role_arn": "string" (optional, for assume_role),
            "external_id": "string" (optional, for assume_role),
            "access_key_id": "string" (optional, for access_key),
            "secret_access_key": "string" (optional, for access_key),
            "is_active": boolean (optional)
        }
    
    Returns:
        { updated credential object }
    """
    data = request.get_json()
    
    if not data:
        raise ValidationError(
            message="Request body is required",
            details={"reason": "missing_body"}
        )
    
    # Validate credential ID
    credential_id = data.get('id')
    if not credential_id:
        raise ValidationError(
            message="Credential ID is required",
            details={"missing_fields": ["id"]}
        )
    
    # Find credential
    credential = db.session.get(AWSCredential, credential_id)
    if not credential:
        raise NotFoundError(
            message="Credential not found",
            details={"credential_id": credential_id}
        )
    
    # Update name if provided
    if 'name' in data and data['name']:
        new_name = data['name'].strip()
        if len(new_name) < 1 or len(new_name) > 100:
            raise ValidationError(
                message="Name must be between 1 and 100 characters",
                details={"field": "name", "reason": "invalid_length"}
            )
        credential.name = new_name
    
    # Update account_id if provided
    if 'account_id' in data and data['account_id']:
        new_account_id = data['account_id'].strip()
        if not validate_account_id(new_account_id):
            raise ValidationError(
                message="Invalid AWS account ID. Must be 12 digits",
                details={"field": "account_id", "reason": "invalid_format"}
            )
        credential.account_id = new_account_id
    
    # Update type-specific fields
    if credential.credential_type == 'assume_role':
        if 'role_arn' in data and data['role_arn']:
            new_role_arn = data['role_arn'].strip()
            if not validate_role_arn(new_role_arn):
                raise ValidationError(
                    message="Invalid Role ARN format",
                    details={"field": "role_arn", "reason": "invalid_format"}
                )
            credential.role_arn = new_role_arn
        
        if 'external_id' in data:
            credential.external_id = data['external_id'].strip() if data['external_id'] else None
    else:  # access_key
        if 'access_key_id' in data and data['access_key_id']:
            credential.access_key_id = data['access_key_id'].strip()
        
        if 'secret_access_key' in data and data['secret_access_key']:
            credential.set_secret_access_key(data['secret_access_key'].strip())
    
    # Update is_active if provided
    if 'is_active' in data:
        credential.is_active = bool(data['is_active'])
    
    db.session.commit()
    
    return jsonify(credential.to_dict(mask_sensitive=True)), 200


@api_bp.route('/credentials/delete', methods=['POST'])
@admin_required
def delete_credential():
    """
    Delete an AWS credential
    
    Request body:
        {
            "id": number (required)
        }
    
    Returns:
        { "message": "Credential deleted successfully" }
    """
    data = request.get_json()
    
    if not data:
        raise ValidationError(
            message="Request body is required",
            details={"reason": "missing_body"}
        )
    
    # Validate credential ID
    credential_id = data.get('id')
    if not credential_id:
        raise ValidationError(
            message="Credential ID is required",
            details={"missing_fields": ["id"]}
        )
    
    # Find credential
    credential = db.session.get(AWSCredential, credential_id)
    if not credential:
        raise NotFoundError(
            message="Credential not found",
            details={"credential_id": credential_id}
        )
    
    # Delete credential (cascade will handle user assignments)
    db.session.delete(credential)
    db.session.commit()
    
    return jsonify({
        'message': 'Credential deleted successfully'
    }), 200


@api_bp.route('/credentials/validate', methods=['POST'])
@admin_required
def validate_credential():
    """
    Validate an AWS credential by testing connection to AWS
    
    Request body:
        {
            "id": number (required) - existing credential ID
        }
        OR
        {
            "credential_type": "assume_role" | "access_key" (required),
            "role_arn": "string" (required for assume_role),
            "external_id": "string" (optional for assume_role),
            "access_key_id": "string" (required for access_key),
            "secret_access_key": "string" (required for access_key)
        }
    
    Returns:
        { "valid": boolean, "account_id": "string" (if valid), "error": "string" (if invalid) }
    """
    data = request.get_json()
    
    if not data:
        raise ValidationError(
            message="Request body is required",
            details={"reason": "missing_body"}
        )
    
    credential_config = {}
    base_credentials = None
    credential_type = None
    
    # Check if validating existing credential by ID
    if 'id' in data:
        credential_id = data['id']
        credential = db.session.get(AWSCredential, credential_id)
        if not credential:
            raise NotFoundError(
                message="Credential not found",
                details={"credential_id": credential_id}
            )
        
        credential_type = credential.credential_type
        
        if credential_type == 'assume_role':
            credential_config = {
                'role_arn': credential.role_arn,
                'external_id': credential.external_id
            }
            # Get base credentials for assume role
            base_config = BaseAssumeRoleConfig.query.first()
            if not base_config:
                raise ValidationError(
                    message="Base Assume Role configuration not found. Please configure it first.",
                    details={"reason": "missing_base_config"}
                )
            base_credentials = {
                'access_key_id': base_config.access_key_id,
                'secret_access_key': base_config.get_secret_access_key()
            }
        else:
            credential_config = {
                'access_key_id': credential.access_key_id,
                'secret_access_key': credential.get_secret_access_key()
            }
    else:
        # Validating new credential data
        credential_type = data.get('credential_type')
        if not credential_type:
            raise ValidationError(
                message="Either 'id' or 'credential_type' is required",
                details={"reason": "missing_identifier"}
            )
        
        if credential_type == 'assume_role':
            role_arn = data.get('role_arn', '').strip()
            if not role_arn:
                raise ValidationError(
                    message="Role ARN is required for assume_role validation",
                    details={"missing_fields": ["role_arn"]}
                )
            credential_config = {
                'role_arn': role_arn,
                'external_id': data.get('external_id', '').strip() or None
            }
            # Get base credentials for assume role
            base_config = BaseAssumeRoleConfig.query.first()
            if not base_config:
                raise ValidationError(
                    message="Base Assume Role configuration not found. Please configure it first.",
                    details={"reason": "missing_base_config"}
                )
            base_credentials = {
                'access_key_id': base_config.access_key_id,
                'secret_access_key': base_config.get_secret_access_key()
            }
        elif credential_type == 'access_key':
            access_key_id = data.get('access_key_id', '').strip()
            secret_access_key = data.get('secret_access_key', '').strip()
            
            if not access_key_id or not secret_access_key:
                raise ValidationError(
                    message="Access Key ID and Secret Access Key are required",
                    details={"missing_fields": ["access_key_id", "secret_access_key"]}
                )
            credential_config = {
                'access_key_id': access_key_id,
                'secret_access_key': secret_access_key
            }
        else:
            raise ValidationError(
                message="Invalid credential type",
                details={"field": "credential_type", "reason": "invalid_value"}
            )
    
    # Validate the credential
    try:
        provider = AWSCredentialProvider(
            credential_type=credential_type,
            credential_config=credential_config,
            base_credentials=base_credentials
        )
        provider.validate()
        account_id = provider.get_account_id()
        
        return jsonify({
            'valid': True,
            'account_id': account_id
        }), 200
        
    except CredentialError as e:
        return jsonify({
            'valid': False,
            'error': str(e)
        }), 200
    except Exception as e:
        return jsonify({
            'valid': False,
            'error': f"Validation failed: {str(e)}"
        }), 200


@api_bp.route('/credentials/base-role', methods=['GET'])
@admin_required
def get_base_role():
    """
    Get base Assume Role configuration
    
    Returns:
        { base role config object with masked sensitive data }
        OR
        { "configured": false } if not configured
    """
    config = BaseAssumeRoleConfig.query.first()
    
    if not config:
        return jsonify({
            'configured': False
        }), 200
    
    return jsonify({
        'configured': True,
        'data': config.to_dict(mask_sensitive=True)
    }), 200


@api_bp.route('/credentials/base-role', methods=['POST'])
@admin_required
def update_base_role():
    """
    Update base Assume Role configuration
    
    Request body:
        {
            "access_key_id": "string" (required),
            "secret_access_key": "string" (required)
        }
    
    Returns:
        { base role config object }
    """
    data = request.get_json()
    
    if not data:
        raise ValidationError(
            message="Request body is required",
            details={"reason": "missing_body"}
        )
    
    # Validate required fields
    access_key_id = data.get('access_key_id', '').strip()
    secret_access_key = data.get('secret_access_key', '').strip()
    
    if not access_key_id:
        raise ValidationError(
            message="Access Key ID is required",
            details={"missing_fields": ["access_key_id"]}
        )
    
    if not secret_access_key:
        raise ValidationError(
            message="Secret Access Key is required",
            details={"missing_fields": ["secret_access_key"]}
        )
    
    # Validate the credentials before saving
    try:
        provider = AWSCredentialProvider(
            credential_type='access_key',
            credential_config={
                'access_key_id': access_key_id,
                'secret_access_key': secret_access_key
            }
        )
        provider.validate()
    except CredentialError as e:
        raise ValidationError(
            message=f"Invalid credentials: {str(e)}",
            details={"reason": "validation_failed"}
        )
    except Exception as e:
        raise ValidationError(
            message=f"Credential validation failed: {str(e)}",
            details={"reason": "validation_error"}
        )
    
    # Get or create config
    config = BaseAssumeRoleConfig.query.first()
    
    if config:
        # Update existing config
        config.access_key_id = access_key_id
        config.set_secret_access_key(secret_access_key)
    else:
        # Create new config
        config = BaseAssumeRoleConfig(
            access_key_id=access_key_id
        )
        config.set_secret_access_key(secret_access_key)
        db.session.add(config)
    
    db.session.commit()
    
    return jsonify({
        'message': 'Base Assume Role configuration updated successfully',
        'data': config.to_dict(mask_sensitive=True)
    }), 200