"""API Request Handlers.

This module contains all HTTP request handlers for the REST API.
Implements rate limiting, request validation, and error handling.

Author: David Kim
Created: January 2024

API Rate Limits:
- Anonymous requests: 100 requests per minute
- Authenticated requests: 1000 requests per minute
- Admin requests: 5000 requests per minute

Error Codes:
- 400: Bad Request (validation error)
- 401: Unauthorized (authentication required)
- 403: Forbidden (insufficient permissions)
- 404: Not Found
- 429: Too Many Requests (rate limit exceeded)
- 500: Internal Server Error
"""

from dataclasses import dataclass
from typing import Any

# Rate limit configuration
RATE_LIMIT_ANONYMOUS = 100
RATE_LIMIT_AUTHENTICATED = 1000
RATE_LIMIT_ADMIN = 5000
RATE_LIMIT_WINDOW_SECONDS = 60


@dataclass
class APIResponse:
    """Standard API response format."""

    success: bool
    data: Any | None = None
    error: str | None = None
    error_code: int | None = None


class UserHandler:
    """Handles user-related API endpoints.

    Endpoints:
    - GET /api/users - List users (admin only)
    - GET /api/users/{id} - Get user details
    - POST /api/users - Create new user
    - PUT /api/users/{id} - Update user
    - DELETE /api/users/{id} - Delete user (admin only)
    """

    async def list_users(self, page: int = 1, limit: int = 20) -> APIResponse:
        """List all users with pagination."""
        pass

    async def get_user(self, user_id: str) -> APIResponse:
        """Get user details by ID."""
        pass

    async def create_user(self, data: dict[str, Any]) -> APIResponse:
        """Create a new user account."""
        pass

    async def update_user(self, user_id: str, data: dict[str, Any]) -> APIResponse:
        """Update user information."""
        pass

    async def delete_user(self, user_id: str) -> APIResponse:
        """Soft delete a user account."""
        pass


class ProjectHandler:
    """Handles project-related API endpoints.

    Endpoints:
    - GET /api/projects - List projects
    - GET /api/projects/{id} - Get project details
    - POST /api/projects - Create project
    - PUT /api/projects/{id} - Update project
    - DELETE /api/projects/{id} - Archive project
    """

    async def list_projects(
        self,
        owner_id: str | None = None,
        status: str | None = None,
    ) -> APIResponse:
        """List projects with optional filtering."""
        pass

    async def get_project(self, project_id: str) -> APIResponse:
        """Get project details including team members."""
        pass

    async def create_project(self, data: dict[str, Any]) -> APIResponse:
        """Create a new project."""
        pass


class FileHandler:
    """Handles file upload and management endpoints.

    Supported file types: pdf, doc, docx, xls, xlsx, png, jpg, gif
    Maximum file size: 50MB
    Storage backend: S3-compatible object storage

    Endpoints:
    - POST /api/files/upload - Upload file
    - GET /api/files/{id} - Download file
    - DELETE /api/files/{id} - Delete file
    """

    MAX_FILE_SIZE_MB = 50
    ALLOWED_EXTENSIONS = ["pdf", "doc", "docx", "xls", "xlsx", "png", "jpg", "gif"]

    async def upload_file(self, file_data: bytes, filename: str) -> APIResponse:
        """Upload a file to storage."""
        pass

    async def download_file(self, file_id: str) -> bytes:
        """Download a file from storage."""
        pass

    async def delete_file(self, file_id: str) -> APIResponse:
        """Delete a file from storage."""
        pass
