import os
import logging
import asyncio
import yaml
from typing import Dict, List, Any, Tuple, Optional
from abc import ABC, abstractmethod

import gradio as gr
from dotenv import load_dotenv
from langchain.llms import HuggingFaceHub
from langchain.agents import initialize_agent, AgentType
from langchain.chains import LLMChain
from langchain.prompts import PromptTemplate

# Load environment variables
load_dotenv()

# Custom Exceptions
class CodeFusionError(Exception):
    """Base exception class for CodeFusion."""
    pass

class AgentInitializationError(CodeFusionError):
    """Raised when there's an error initializing the agent."""
    pass

class ToolExecutionError(CodeFusionError):
    """Raised when there's an error executing a tool."""
    pass

# Utility Functions
def load_config() -> Dict:
    """Load configuration from config.yaml file or use default values."""
    config_path = 'config.yaml'
    default_config = {
        'model_name': "google/flan-t5-xl",
        'api_key': "your_default_api_key_here",
        'temperature': 0.5,
        'verbose': True
    }
    
    try:
        with open(config_path, 'r') as config_file:
            config = yaml.safe_load(config_file)
    except FileNotFoundError:
        print(f"Config file not found at {config_path}. Using default configuration.")
        config = default_config
    
    # Override with environment variables if set
    config['api_key'] = os.getenv('HUGGINGFACE_API_KEY', config['api_key'])
    return config

def setup_logging() -> logging.Logger:
    """Set up logging configuration."""
    logging.basicConfig(
        level=logging.INFO,
        format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
        filename='codefusion.log'
    )
    return logging.getLogger(__name__)

# Load configuration and set up logging
config = load_config()
logger = setup_logging()

# Tool Classes
class Tool(ABC):
    """Abstract base class for all tools used by the agent."""

    def __init__(self, name: str, description: str):
        self.name = name
        self.description = description
        self.llm = HuggingFaceHub(
            repo_id=config['model_name'],
            model_kwargs={"temperature": config['temperature']},
            huggingfacehub_api_token=config['api_key']
        )

    @abstractmethod
    async def run(self, arguments: Dict[str, Any]) -> Dict[str, str]:
        """Execute the tool's functionality."""
        pass

class CodeGenerationTool(Tool):
    """Tool for generating code snippets in various languages."""

    def __init__(self):
        super().__init__("Code Generation", "Generates code snippets in various languages.")
        self.prompt_template = PromptTemplate(
            input_variables=["language", "code_description"],
            template="Generate {language} code for: {code_description}"
        )
        self.chain = LLMChain(llm=self.llm, prompt=self.prompt_template)

    async def run(self, arguments: Dict[str, str]) -> Dict[str, str]:
        language = arguments.get("language", "python")
        code_description = arguments.get("code_description", "print('Hello, World!')")
        try:
            code = await self.chain.arun(language=language, code_description=code_description)
            return {"output": code}
        except Exception as e:
            logger.error(f"Error in CodeGenerationTool: {e}")
            raise ToolExecutionError(f"Failed to generate code: {e}")

class CodeExplanationTool(Tool):
    """Tool for explaining code snippets."""

    def __init__(self):
        super().__init__("Code Explanation", "Explains code snippets in simple terms.")
        self.prompt_template = PromptTemplate(
            input_variables=["code"],
            template="Explain the following code in simple terms:\n\n{code}"
        )
        self.chain = LLMChain(llm=self.llm, prompt=self.prompt_template)

    async def run(self, arguments: Dict[str, str]) -> Dict[str, str]:
        code = arguments.get("code", "print('Hello, World!')")
        try:
            explanation = await self.chain.arun(code=code)
            return {"output": explanation}
        except Exception as e:
            logger.error(f"Error in CodeExplanationTool: {e}")
            raise ToolExecutionError(f"Failed to explain code: {e}")

class DebuggingTool(Tool):
    """Tool for debugging code snippets."""

    def __init__(self):
        super().__init__("Debugging", "Helps identify and fix issues in code snippets.")
        self.prompt_template = PromptTemplate(
            input_variables=["code", "error_message"],
            template="Debug the following code:\n\n{code}\n\nError message: {error_message}"
        )
        self.chain = LLMChain(llm=self.llm, prompt=self.prompt_template)

    async def run(self, arguments: Dict[str, str]) -> Dict[str, str]:
        code = arguments.get("code", "")
        error_message = arguments.get("error_message", "")
        try:
            debug_result = await self.chain.arun(code=code, error_message=error_message)
            return {"output": debug_result}
        except Exception as e:
            logger.error(f"Error in DebuggingTool: {e}")
            raise ToolExecutionError(f"Failed to debug code: {e}")

# Agent Class
class Agent:
    """Represents an AI agent with specific tools and capabilities."""

    def __init__(self, name: str, role: str, tools: List[Tool]):
        self.name = name
        self.role = role
        self.tools = tools
        self.memory: List[tuple] = []
        
        try:
            self.llm = HuggingFaceHub(
                repo_id=config['model_name'],
                model_kwargs={"temperature": config['temperature']},
                huggingfacehub_api_token=config['api_key']
            )
            self.agent = initialize_agent(
                llm=self.llm,
                tools=self.tools,
                agent_type=AgentType.ZERO_SHOT_REACT_DESCRIPTION,
                verbose=config['verbose']
            )
        except Exception as e:
            logger.error(f"Error initializing agent: {e}")
            raise AgentInitializationError(f"Failed to initialize agent: {e}")

    async def act(self, prompt: str, context: str) -> str:
        """Perform an action based on the given prompt and context."""
        self.memory.append((prompt, context))
        try:
            action = await self.agent.arun(prompt, context)
            return action
        except Exception as e:
            logger.error(f"Error during agent action: {e}")
            raise

    def __str__(self) -> str:
        return f"Agent: {self.name} (Role: {self.role})"

# Main application functions
async def run(message: str, history: List[Tuple[str, str]]) -> str:
    """Process user input and generate a response using the agent system."""
    agent = Agent(
        name="CodeFusion",
        role="AI Coding Assistant",
        tools=[CodeGenerationTool(), CodeExplanationTool(), DebuggingTool()]
    )
    context = "\n".join([f"Human: {h[0]}\nAI: {h[1]}" for h in history])
    try:
        response = await agent.act(message, context)
        return response
    except Exception as e:
        logger.error(f"Error processing request: {e}")
        return "I apologize, but an error occurred while processing your request. Please try again."

async def main():
    """Main function to run the Gradio interface."""
    examples = [
        ["What is the purpose of this AI agent?", "I am an AI coding assistant designed to help with various programming tasks."],
        ["Can you help me generate a Python function to calculate the factorial of a number?", "Certainly! Here's a Python function to calculate the factorial of a number:"],
        ["Explain the concept of recursion in programming.", "Recursion is a programming concept where a function calls itself to solve a problem by breaking it down into smaller, similar subproblems."],
    ]

    gr.ChatInterface(
        fn=run,
        title="CodeFusion: Your AI Coding Assistant",
        description="Ask me about code generation, explanation, debugging, or any other coding task!",
        examples=examples,
        theme="default"
    ).launch()

# Simple testing framework
def run_tests():
    """Run basic tests for the CodeFusion components."""
    
    async def test_code_generation():
        tool = CodeGenerationTool()
        result = await tool.run({"language": "python", "code_description": "function to add two numbers"})
        assert "def" in result["output"], "Code generation failed to produce a function"
        print("Code Generation Test: Passed")

    async def test_code_explanation():
        tool = CodeExplanationTool()
        result = await tool.run({"code": "def factorial(n):\n    return 1 if n == 0 else n * factorial(n-1)"})
        assert "recursive" in result["output"].lower(), "Code explanation failed to mention recursion"
        print("Code Explanation Test: Passed")

    async def test_debugging():
        tool = DebuggingTool()
        result = await tool.run({"code": "def divide(a, b):\n    return a / b", "error_message": "ZeroDivisionError"})
        assert "zero" in result["output"].lower(), "Debugging failed to address division by zero"
        print("Debugging Test: Passed")

    async def test_agent():
        agent = Agent("TestAgent", "Tester", [CodeGenerationTool(), CodeExplanationTool(), DebuggingTool()])
        result = await agent.act("Generate a Python function to calculate the square of a number", "")
        assert "def" in result and "return" in result, "Agent failed to generate a proper function"
        print("Agent Test: Passed")

    async def run_all_tests():
        await test_code_generation()
        await test_code_explanation()
        await test_debugging()
        await test_agent()

    asyncio.run(run_all_tests())

if __name__ == "__main__":
    import sys
    if len(sys.argv) > 1 and sys.argv[1] == "--test":
        run_tests()
    else:
        asyncio.run(main())