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import pandas as pd
import json
import os
import asyncio
import logging
import numpy as np
import textwrap

try:
    from google import generativeai as genai
    from google.generativeai import types as genai_types # For GenerateContentConfig, SafetySetting etc.
    from google.generativeai.types import HarmCategory, HarmBlockThreshold # Specific enums
except ImportError:
    logging.error("Google Generative AI library not found. Please install it: pip install google-generativeai", exc_info=True)
    # Define dummy classes/variables if import fails, so app.py can try to run
    # (though app.py already has EB_AGENT_AVAILABLE check)
    class genai: Client = None # type: ignore
    class genai_types: # type: ignore
        EmbedContentConfig = None
        GenerateContentConfig = None
        SafetySetting = None
    class HarmCategory: # type: ignore
        HARM_CATEGORY_HATE_SPEECH = "HARM_CATEGORY_HATE_SPEECH"
        HARM_CATEGORY_HARASSMENT = "HARM_CATEGORY_HARASSMENT"
        HARM_CATEGORY_SEXUALLY_EXPLICIT = "HARM_CATEGORY_SEXUALLY_EXPLICIT"
        HARM_CATEGORY_DANGEROUS_CONTENT = "HARM_CATEGORY_DANGEROUS_CONTENT"
    class HarmBlockThreshold: # type: ignore
        BLOCK_LOW_AND_ABOVE = "BLOCK_LOW_AND_ABOVE"
        BLOCK_MEDIUM_AND_ABOVE = "BLOCK_MEDIUM_AND_ABOVE"
        BLOCK_NONE = "BLOCK_NONE"


# --- Configuration Constants ---
# These are defined here because app.py imports them.
# User should ensure these are appropriate for their needs.

GEMINI_API_KEY = os.getenv('GEMINI_API_KEY', "")
if not GEMINI_API_KEY:
    logging.warning("GEMINI_API_KEY environment variable not set. EB Agent will not function.")

# Model names (as used in app.py imports from this module)
LLM_MODEL_NAME = "gemini-1.5-flash-latest" # Changed to 1.5-flash as it's generally preferred; user had 2.0-flash. Adjust if needed.
GEMINI_EMBEDDING_MODEL_NAME = "text-embedding-004" # Common embedding model; user had gemini-embedding-exp-03-07. Adjust if needed.

# Default Generation Config (app.py imports this as EB_AGENT_GEN_CONFIG)
GENERATION_CONFIG_PARAMS = {
    "temperature": 0.7,
    "top_p": 0.95,
    "top_k": 40,
    "max_output_tokens": 8192,
    "candidate_count": 1, # Important for non-streaming
    # "stop_sequences": [...] # Optional
}

# Default Safety Settings (app.py imports this as EB_AGENT_SAFETY_SETTINGS)
DEFAULT_SAFETY_SETTINGS = [
    {"category": HarmCategory.HARM_CATEGORY_HATE_SPEECH, "threshold": HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE},
    {"category": HarmCategory.HARM_CATEGORY_HARASSMENT, "threshold": HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE},
    {"category": HarmCategory.HARM_CATEGORY_SEXUALLY_EXPLICIT, "threshold": HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE},
    {"category": HarmCategory.HARM_CATEGORY_DANGEROUS_CONTENT, "threshold": HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE},
]

# Placeholder for RAG documents DataFrame (app.py imports this as eb_agent_default_rag_docs)
# In a real application, this would be loaded from a file or database.
df_rag_documents = pd.DataFrame({
    'text': [
        "Employer branding focuses on how an organization is perceived as an employer by potential and current employees.",
        "Key metrics for employer branding include employee engagement, candidate quality, and retention rates.",
        "LinkedIn is a crucial platform for showcasing company culture and attracting talent.",
        "Analyzing follower demographics and post engagement helps refine employer branding strategies."
    ]
})

# --- Client Initialization ---
# This client will be used by the agent instances.
# It's initialized once when the module is loaded.
client = None
if GEMINI_API_KEY and genai.Client: # Check if genai.Client is not None (due to dummy class on import error)
    try:
        # genai.configure(api_key=GEMINI_API_KEY) # Alternative: global configuration
        client = genai.Client(api_key=GEMINI_API_KEY)
        logging.info("Google GenAI client initialized successfully.")
    except Exception as e:
        logging.error(f"Failed to initialize Google GenAI client: {e}", exc_info=True)
else:
    logging.warning("Google GenAI client could not be initialized (GEMINI_API_KEY missing or library import failed).")


class AdvancedRAGSystem:
    """
    Handles Retrieval Augmented Generation by embedding documents and finding relevant context for queries.
    """
    def __init__(self, documents_df: pd.DataFrame, embedding_model_name: str):
        self.documents_df = documents_df.copy() # Work on a copy
        self.embedding_model_name = embedding_model_name
        self.embeddings: np.ndarray | None = None # Populated by async initialize_embeddings
        logging.info(f"AdvancedRAGSystem initialized with embedding model: {self.embedding_model_name}")

    def _embed_single_document_sync(self, text: str) -> np.ndarray:
        """Synchronous helper to embed a single piece of text."""
        if not client:
            raise ConnectionError("GenAI client not initialized for RAG embedding.")
        if not text or not isinstance(text, str): # Basic validation
            logging.warning("Attempted to embed empty or non-string text. Returning zero vector.")
            # Attempt to get model's embedding dimension, otherwise use a common default (e.g., 768)
            # This is tricky without a live model call. For now, let's assume it will be filtered or handled.
            # If we must return a vector, its dimensionality needs to be known.
            # For simplicity, errors during embedding will be logged and might lead to skipping the doc.
            raise ValueError("Cannot embed empty or non-string text.")

        # Using client.models.embed_content as per user's provided snippets
        response = client.models.embed_content(
            model=self.embedding_model_name, # e.g., "text-embedding-004" or "gemini-embedding-exp-03-07"
            contents=text, # API takes 'contents' (plural) but can be a single string for single embedding
            config=genai_types.EmbedContentConfig(task_type="SEMANTIC_SIMILARITY") if genai_types.EmbedContentConfig else None
        )
        # Assuming response.embeddings is the list of floats for a single content string, as per user's snippet.
        return np.array(response.embeddings)

    async def initialize_embeddings(self):
        """Asynchronously embeds all documents in the documents_df. Should be called once."""
        if self.documents_df.empty:
            logging.info("RAG documents DataFrame is empty. No embeddings to initialize.")
            self.embeddings = np.array([])
            return

        if not client:
            logging.error("GenAI client not available for RAG embedding initialization.")
            self.embeddings = np.array([])
            return

        logging.info(f"Starting RAG document embedding for {len(self.documents_df)} documents...")
        embedded_docs_list = []
        for index, row in self.documents_df.iterrows():
            text_to_embed = row.get('text')
            if not text_to_embed or not isinstance(text_to_embed, str):
                logging.warning(f"Skipping document at index {index} due to invalid text: {text_to_embed}")
                continue
            try:
                # Wrap the synchronous SDK call in asyncio.to_thread
                embedding_array = await asyncio.to_thread(self._embed_single_document_sync, text_to_embed)
                embedded_docs_list.append(embedding_array)
            except Exception as e:
                logging.error(f"Error embedding document text (index {index}) '{str(text_to_embed)[:50]}...': {e}", exc_info=False) # exc_info=False for brevity in loop

        if not embedded_docs_list:
            self.embeddings = np.array([])
            logging.warning("No documents were successfully embedded for RAG.")
        else:
            try:
                self.embeddings = np.vstack(embedded_docs_list)
                logging.info(f"Successfully embedded {len(embedded_docs_list)} documents for RAG. Embedding matrix shape: {self.embeddings.shape}")
            except ValueError as ve: # Handles cases like empty list or inconsistent shapes if errors weren't caught properly
                logging.error(f"Error stacking embeddings: {ve}. Check individual embedding errors.", exc_info=True)
                self.embeddings = np.array([])


    async def retrieve_relevant_info(self, query: str, top_k: int = 3) -> str:
        """Retrieves relevant document snippets for a given query using vector similarity."""
        if self.embeddings is None or self.embeddings.size == 0 or self.documents_df.empty:
            logging.debug("RAG system not initialized or no documents/embeddings available for retrieval.")
            return ""
        if not query or not isinstance(query, str):
            logging.debug("Empty or invalid query for RAG retrieval.")
            return ""
        if not client:
            logging.error("GenAI client not available for RAG query embedding.")
            return ""

        try:
            query_vector = await asyncio.to_thread(self._embed_single_document_sync, query)
        except Exception as e:
            logging.error(f"Error embedding query '{str(query)[:50]}...': {e}", exc_info=False)
            return ""

        if query_vector.ndim == 0 or query_vector.size == 0:
             logging.warning(f"Query vector embedding failed or is empty for query: {str(query)[:50]}")
             return ""
        if query_vector.ndim > 1: # Should be 1D
            query_vector = query_vector.flatten()

        try:
            # Cosine similarity is dot product of normalized vectors.
            # For simplicity, using dot product directly. Normalize if true cosine sim is needed.
            scores = np.dot(self.embeddings, query_vector) # self.embeddings (N, D), query_vector (D,) -> scores (N,)
            
            if scores.size == 0:
                return ""

            actual_top_k = min(top_k, len(self.documents_df), len(scores))
            if actual_top_k <= 0: return "" # Ensure top_k is positive

            # Get indices of top_k scores in descending order
            top_indices = np.argsort(scores)[-actual_top_k:][::-1]
            
            valid_top_indices = [idx for idx in top_indices if 0 <= idx < len(self.documents_df)]
            if not valid_top_indices: return ""

            # Retrieve the 'text' field from the original DataFrame
            context_parts = [self.documents_df.iloc[i]['text'] for i in valid_top_indices if 'text' in self.documents_df.columns]
            context = "\n\n---\n\n".join(context_parts)
            logging.debug(f"Retrieved RAG context for query '{str(query)[:50]}...':\n{context[:200]}...")
            return context
        except Exception as e:
            logging.error(f"Error during RAG retrieval (dot product/sorting): {e}", exc_info=True)
            return ""


class EmployerBrandingAgent:
    """
    An agent that uses Generative AI to provide insights on employer branding
    based on provided DataFrames and RAG context.
    """
    def __init__(self,
                 all_dataframes: dict,
                 rag_documents_df: pd.DataFrame, # For RAG system
                 llm_model_name: str,
                 embedding_model_name: str, # For RAG system
                 generation_config_dict: dict,
                 safety_settings_list_of_dicts: list,
                 # client_instance, # Using global client for simplicity now
                 force_sandbox: bool = False # Parameter from app.py, currently unused here
                ):
        # self.client = client_instance # If client were passed
        self.all_dataframes = {k: df.copy() for k, df in all_dataframes.items()} # Work with copies
        self.schemas_representation = self._get_all_schemas_representation() # Sync method
        
        self.chat_history = [] # Stores chat in API format: [{"role": "user/model", "parts": [{"text": "..."}]}]
                               # This will be set by app.py before calling process_query

        self.llm_model_name = llm_model_name
        self.generation_config_dict = generation_config_dict
        self.safety_settings_list_of_dicts = safety_settings_list_of_dicts
        
        self.embedding_model_name = embedding_model_name
        self.rag_system = AdvancedRAGSystem(rag_documents_df, self.embedding_model_name)
        # Note: self.rag_system.initialize_embeddings() must be called externally (e.g., in app.py)
        
        self.force_sandbox = force_sandbox # Store if needed for tool use later
        logging.info(f"EmployerBrandingAgent initialized. LLM: {self.llm_model_name}, Embedding: {self.embedding_model_name}. RAG system created.")

    def _get_all_schemas_representation(self) -> str:
        """Generates a string representation of the schemas of all DataFrames."""
        schema_descriptions = ["DataFrames available for analysis:"]
        for key, df in self.all_dataframes.items():
            df_name = f"df_{key}" # Consistent naming for the agent to refer to
            columns = ", ".join(df.columns)
            shape = df.shape
            if df.empty:
                schema = f"\n--- DataFrame: {df_name} ---\nStatus: Empty\nShape: {shape}\nColumns: {columns}"
            else:
                # Basic stats for numeric columns, first few unique for objects
                sample_info_parts = []
                for col in df.columns:
                    if pd.api.types.is_numeric_dtype(df[col]) and not df[col].empty:
                        sample_info_parts.append(f"{col} (numeric, e.g., mean: {df[col].mean():.2f})")
                    elif pd.api.types.is_datetime64_any_dtype(df[col]) and not df[col].empty:
                         sample_info_parts.append(f"{col} (datetime, e.g., min: {df[col].min()}, max: {df[col].max()})")
                    elif not df[col].empty:
                        unique_vals = df[col].unique()
                        display_unique = ', '.join(map(str, unique_vals[:3]))
                        if len(unique_vals) > 3: display_unique += ", ..."
                        sample_info_parts.append(f"{col} (object, e.g., {display_unique})")
                    else:
                        sample_info_parts.append(f"{col} (empty)")

                schema = (f"\n--- DataFrame: {df_name} ---\nShape: {shape}\nColumns & Sample Info:\n  " + "\n  ".join(sample_info_parts))
            schema_descriptions.append(schema)
        return "\n".join(schema_descriptions)

    async def _build_prompt_for_current_turn(self, raw_user_query: str) -> str:
        """
        Constructs the full prompt for the current turn, including system instructions,
        DataFrame schemas, RAG context, and the user's query.
        """
        # System instruction part
        prompt_parts = [
            "You are an expert Employer Branding Analyst and a helpful AI assistant. "
            "Your goal is to provide insightful analysis based on the provided LinkedIn data. "
            "When asked to generate Pandas code, ensure it is correct, runnable, and clearly explained. "
            "When providing insights, be specific and refer to the data where possible."
        ]

        # Schema information
        prompt_parts.append("\n\n--- AVAILABLE DATA ---")
        prompt_parts.append(self.schemas_representation)

        # RAG context
        if self.rag_system.embeddings is not None and self.rag_system.embeddings.size > 0 : # Check if RAG is initialized
            logging.debug(f"Retrieving RAG context for query: {raw_user_query[:50]}...")
            rag_context = await self.rag_system.retrieve_relevant_info(raw_user_query)
            if rag_context:
                prompt_parts.append("\n\n--- RELEVANT CONTEXTUAL INFORMATION (from documents) ---")
                prompt_parts.append(rag_context)
            else:
                logging.debug("No relevant RAG context found.")
        else:
            logging.debug("RAG system not initialized or embeddings not available, skipping RAG context retrieval.")


        # User's current query
        prompt_parts.append("\n\n--- USER REQUEST ---")
        prompt_parts.append(f"Based on all the information above, please respond to the following user query:\n{raw_user_query}")
        
        final_prompt = "\n".join(prompt_parts)
        logging.debug(f"Built prompt for current turn (first 300 chars): {final_prompt[:300]}")
        return final_prompt

    async def process_query(self, raw_user_query_this_turn: str) -> str:
        """
        Processes the user's query, incorporating chat history, DataFrame schemas, and RAG.
        The agent's self.chat_history is expected to be set by the calling application (app.py)
        and should contain the history *before* the current raw_user_query_this_turn.
        This method returns the AI's response string. app.py will then update the agent's
        chat history with the raw_user_query_this_turn and this response.
        """
        if not client:
            logging.error("GenAI client not initialized. Cannot process query.")
            return "Error: The AI Agent is not available due to a configuration issue with the AI service."

        if not raw_user_query_this_turn.strip():
            return "Please provide a query."

        # 1. Prepare the augmented prompt for the *current* user query
        # This prompt includes system instructions, schemas, RAG, and the current raw query.
        augmented_current_user_prompt_text = await self._build_prompt_for_current_turn(raw_user_query_this_turn)

        # 2. Construct the full list of contents for the API call
        # self.chat_history should be in API format: [{"role": "user/model", "parts": [{"text": "..."}]}]
        # It contains history *before* the current raw_user_query_this_turn.
        api_call_contents = []
        if self.chat_history: # Add previous turns if any
            api_call_contents.extend(self.chat_history)
        
        # Add the current user turn, using the fully augmented prompt as its content
        api_call_contents.append({"role": "user", "parts": [{"text": augmented_current_user_prompt_text}]})
        
        logging.debug(f"Sending to GenAI. Total turns in content: {len(api_call_contents)}")
        if api_call_contents:
             logging.debug(f"Last turn role: {api_call_contents[-1]['role']}, text start: {api_call_contents[-1]['parts'][0]['text'][:100]}")


        # 3. Prepare API configuration
        # Convert safety settings from list of dicts to list of SafetySetting objects if genai_types are available
        api_safety_settings = []
        if genai_types.SafetySetting:
            for ss_dict in self.safety_settings_list_of_dicts:
                try:
                    api_safety_settings.append(genai_types.SafetySetting(**ss_dict))
                except TypeError: # Handles if HarmCategory/HarmBlockThreshold were strings due to import error
                     logging.warning(f"Could not create SafetySetting object from dict: {ss_dict}. Using dict directly.")
                     api_safety_settings.append(ss_dict) # Fallback to dict
        else: # genai_types not available
            api_safety_settings = self.safety_settings_list_of_dicts


        api_generation_config = None
        if genai_types.GenerateContentConfig:
            try:
                api_generation_config = genai_types.GenerateContentConfig(
                    **self.generation_config_dict,
                    safety_settings=api_safety_settings # This should be list of SafetySetting objects or dicts
                )
            except TypeError:
                logging.warning("Could not create GenerateContentConfig object. Using dicts directly for config.")
                # Fallback: if GenerateContentConfig fails, try to pass dicts (might not be supported by client.models.generate_content's 'config' param)
                # The user's snippet uses config=types.GenerateContentConfig(...), so this object is important.
                # If it fails, the call might fail.
                api_generation_config = self.generation_config_dict # This is not ideal for the 'config' parameter.
                # The 'config' parameter of client.models.generate_content expects a GenerateContentConfig object.
                # If we can't create it, we should signal an error or try a different call structure if available.
                # For now, proceed and let the API call potentially fail if config is malformed.
                # A better fallback would be to construct the config parts individually if the main object fails.
                # However, the user's snippet is clear: config=types.GenerateContentConfig(...)
                # So, if genai_types.GenerateContentConfig is None, this will be an issue.

        else: # genai_types.GenerateContentConfig is None (likely import error)
             logging.error("genai_types.GenerateContentConfig not available. Cannot form API config.")
             return "Error: AI Agent configuration problem (GenerateContentConfig type missing)."


        # 4. Make the API call (synchronous SDK call wrapped in asyncio.to_thread)
        try:
            response = await asyncio.to_thread(
                client.models.generate_content, # As per user's snippet
                model=self.llm_model_name,
                contents=api_call_contents,
                config=api_generation_config # Pass the GenerateContentConfig object
            )
            # Extract text. User's snippet uses response.text
            # Check for blocked content or other issues
            if not response.candidates:
                block_reason = response.prompt_feedback.block_reason if response.prompt_feedback else "Unknown"
                logging.warning(f"AI response blocked or empty. Reason: {block_reason}")
                # You might want to inspect response.prompt_feedback for block reasons
                error_message = f"The AI's response was blocked. Reason: {block_reason}."
                if response.prompt_feedback and response.prompt_feedback.block_reason_message:
                    error_message += f" Details: {response.prompt_feedback.block_reason_message}"
                return error_message

            answer = response.text.strip()
            logging.info(f"Successfully received AI response (first 100 chars): {answer[:100]}")

        except Exception as e:
            logging.error(f"Error during GenAI call: {e}", exc_info=True)
            # Check if it's a Google specific API error for more details
            # from google.api_core import exceptions as google_exceptions
            # if isinstance(e, google_exceptions.GoogleAPIError):
            #     answer = f"API Error: {e.message}"
            # else:
            answer = f"# Error during AI processing:\n{type(e).__name__}: {str(e)}"
        
        return answer

    def clear_chat_history(self): # This method is called by app.py
        """Clears the agent's internal chat history."""
        self.chat_history = []
        logging.info("EmployerBrandingAgent chat history cleared by request.")

# --- Module-level function for schema display in app.py ---
def get_all_schemas_representation(all_dataframes: dict) -> str:
    """
    Generates a string representation of the schemas of all DataFrames,
    intended for display in the Gradio UI.
    This is a standalone function as it's imported directly by app.py.
    """
    if not all_dataframes:
        return "No DataFrames are currently loaded."
        
    schema_descriptions = ["DataFrames currently available in the application state:"]
    for key, df in all_dataframes.items():
        df_name = f"df_{key}"
        columns = ", ".join(df.columns)
        shape = df.shape
        if df.empty:
            schema = f"\n--- DataFrame: {df_name} ---\nStatus: Empty\nShape: {shape}\nColumns: {columns}"
        else:
            # Provide a bit more detail for UI display
            sample_data_str = df.head(2).to_markdown(index=False) # Use markdown for better UI rendering
            schema = (f"\n--- DataFrame: {df_name} ---\nShape: {shape}\nColumns: {columns}\n\n<details><summary>Sample Data (first 2 rows of {df_name}):</summary>\n\n{sample_data_str}\n\n</details>")
        schema_descriptions.append(schema)
    return "\n".join(schema_descriptions)