"""
Mock LLM Client for offline lab execution.

All 13 labs use this instead of real API calls.
Provides deterministic responses so students can run labs without API keys.

Usage:
    from mock_llm import MockAnthropic, MockResponse
    
    client = MockAnthropic()
    response = client.messages.create(
        model="claude-sonnet-4",
        max_tokens=1024,
        system="You are a helpful assistant.",
        messages=[{"role": "user", "content": "Hello"}],
        tools=[...]
    )
"""

import json
import re
from typing import Any


class MockContentBlock:
    """Simulates Anthropic's content block responses."""
    
    def __init__(self, type: str = "text", **kwargs):
        self.type = type
        for k, v in kwargs.items():
            setattr(self, k, v)


class MockResponse:
    """Simulates Anthropic's API response."""
    
    def __init__(self, stop_reason: str = "end_turn", content: list = None):
        self.stop_reason = stop_reason
        self.content = content or [MockContentBlock(type="text", text="Mock response")]
    
    def __getitem__(self, key):
        return self.content[key]


_mock_call_count = 0
_MAX_MOCK_CALLS = 20

class MockAnthropic:
    """Simulates the Anthropic client for offline lab execution."""
    
    def __init__(self, api_key: str = "mock-key"):
        self.api_key = api_key
    
    class messages:
        """Simulates Anthropic's messages API."""
        
        @staticmethod
        def create(model: str = None, max_tokens: int = None, system: str = None,
                   messages: list = None, tools: list = None, **kwargs) -> MockResponse:
            """Deterministic mock response based on prompt patterns."""
            global _mock_call_count
            _mock_call_count += 1
            if _mock_call_count >= _MAX_MOCK_CALLS:
                return MockResponse(stop_reason="end_turn", content=[
                    MockContentBlock(type="text", text="Mock completed analysis.")
                ])
            
            if not messages:
                return MockResponse(stop_reason="end_turn", content=[
                    MockContentBlock(type="text", text="No input provided.")
                ])
            
            last_msg = messages[-1]["content"] if messages else ""
            
            # Only trigger tool_use on the first user message (the actual request)
            # After a tool result comes back, always return end_turn
            user_msg_count = sum(1 for m in messages if m.get("role") == "user")
            if user_msg_count > 1:
                return MockResponse(stop_reason="end_turn", content=[
                    MockContentBlock(type="text", text=_generate_text_response(last_msg))
                ])
            
            # Tool calling patterns — return tool_use if prompt asks for it
            if tools and _wants_tool_call(last_msg):
                tool_name = tools[0]["name"]
                tool_input = _generate_tool_input(tool_name, last_msg)
                return MockResponse(stop_reason="tool_use", content=[
                    MockContentBlock(type="tool_use", name=tool_name, input=tool_input)
                ])
            
            # Default text response
            return MockResponse(stop_reason="end_turn", content=[
                MockContentBlock(type="text", text=_generate_text_response(last_msg))
            ])


def _wants_tool_call(prompt: str) -> bool:
    """Detect if the prompt asks for tool use.
    
    Only matches multi-word phrases to avoid false positives
    from common English words in file contents or agent responses.
    """
    tool_triggers = [
        "read file", "read the file", "search for", "search the",
        "write file", "write to", "execute", "run this",
        "find files", "list files", "check if", "verify that",
        "look up", "lookup", "query the", "fetch from",
    ]
    prompt_lower = prompt.lower()
    return any(t in prompt_lower for t in tool_triggers)


def _generate_tool_input(tool_name: str, prompt: str) -> dict:
    """Generate realistic mock tool input based on prompt + tool name."""
    if tool_name == "read_file":
        # Extract filename from prompt
        files = re.findall(r'[\w/.-]+\.\w+', prompt)
        return {"path": files[0] if files else "test.txt", "reasoning": "Reading file as requested"}
    elif tool_name == "search_web":
        return {"query": prompt[:50], "reasoning": "Searching for information"}
    elif tool_name == "write_file":
        return {"path": "output.txt", "content": "Mock content", "reasoning": "Writing output"}
    elif "query" in tool_name.lower():
        return {"query": "SELECT * FROM users LIMIT 5", "reasoning": "Querying database"}
    else:
        return {"reasoning": "Executing tool", "action": prompt[:50]}


def _generate_text_response(prompt: str) -> str:
    """Generate realistic mock text response from tool results or user input."""
    if not prompt or len(prompt) < 5:
        return "I understand your request. How can I help you further?"
    
    prompt_lower = prompt.lower()
    
    # Agent session log responses
    if "session" in prompt_lower and ("agent" in prompt_lower or "tool call" in prompt_lower):
        return "I've analyzed the session log. Here's what I found:\n\n- The agent completed 3 tool calls successfully\n- 1 critical error was detected (database connection timeout)\n- 2 warnings (deprecated API usage)\n- Total session cost: $0.042\n- Recommendation: Check the database connection pool settings"
    
    # File content responses - extract what the file is about
    if "contents of" in prompt_lower:
        if "error" in prompt_lower or "FAIL" in prompt_lower:
            return "I've analyzed the file. It contains session trace data from a production agent deployment. There are signs of a database connection issue that needs investigation."
        if "deploy" in prompt_lower or "log" in prompt_lower:
            return "I've reviewed the deployment log. The system ran 3 tool calls successfully with one critical error. The root cause appears to be a database timeout."
        return "Based on the file contents, I can see it contains sample data with records and configuration details. The key patterns I identified are structured around standard formats."
    
    # Search result responses  
    if "search" in prompt_lower and ("result" in prompt_lower or "found" in prompt_lower):
        return "Here are the search results I found. The most relevant result covers the topic you asked about with specific examples and implementation details."
    
    # Write confirmation responses
    if "successfully wrote" in prompt_lower or "wrote" in prompt_lower:
        return "The file has been written successfully. I've confirmed the content was saved correctly."
    
    # Hello/greetings
    if "hello" in prompt_lower or "hi " in prompt_lower:
        return "Hello! I'm your AI coding agent. How can I help you today?"
    
    # Explanation patterns
    elif "explain" in prompt_lower or "what is" in prompt_lower:
        return "Based on my analysis: this is a well-known pattern in software engineering. The key insight is that it separates concerns and allows for independent evolution of components."
    
    # Error/fix patterns
    elif "error" in prompt_lower or "bug" in prompt_lower or "fix" in prompt_lower:
        return "I found the issue. The problem is a missing null check on line 42. Adding `if value is not None:` before the operation resolves it."
    
    # Test results
    elif "test" in prompt_lower or "pytest" in prompt_lower:
        return "All tests pass. 34 passed, 0 failed, 0 skipped. Completed in 3.62 seconds."
    
    # Summary requests
    elif "summarize" in prompt_lower or "summary" in prompt_lower:
        return "Summary: The document covers three main topics. First, architectural patterns for agent systems. Second, security considerations for production deployments. Third, evaluation methodologies."
    
    else:
        return "I've completed the analysis. Here are the key findings:\n\n1. The approach is viable\n2. Recommended next steps are documented\n3. No blockers identified\n\nWould you like me to proceed with implementation?"


class MockOpenAI:
    """Simulates OpenAI client for offline lab execution."""
    
    def __init__(self, api_key: str = "mock-key"):
        self.api_key = api_key
    
    class chat:
        class completions:
            @staticmethod
            def create(model: str = None, messages: list = None, tools: list = None, **kwargs) -> dict:
                return {
                    "choices": [{
                        "message": {
                            "content": _generate_text_response(messages[-1]["content"] if messages else ""),
                            "tool_calls": None
                        },
                        "finish_reason": "stop"
                    }]
                }


if __name__ == "__main__":
    # Quick test
    client = MockAnthropic()
    resp = client.messages.create(
        messages=[{"role": "user", "content": "Read the file data.txt and summarize it"}],
        tools=[{"name": "read_file", "description": "Read a file"}]
    )
    print(f"Stop reason: {resp.stop_reason}")
    for block in resp.content:
        if block.type == "text":
            print(f"Text: {block.text[:100]}")
        elif block.type == "tool_use":
            print(f"Tool: {block.name}({block.input})")
