# deep_dive_agentic.py

"""
Agentic analytical code generation + execution engine using Hugging Face

FLOW:
User Question
↓
LLM generates pandas code
↓
Python executes code safely
↓
LLM interprets results
↓
Return code + interpretation

Environment:
export HUGGINGFACE_API_TOKEN=...

FIXES APPLIED (v2):
- FIX 1: exec() now uses a single merged namespace dict so result variables
         are reliably written back (Python bug with separate globals/locals).
- FIX 2: Smart result detection — scans namespace for any new DataFrame/Series
         instead of relying on hardcoded variable names (result_1, final_result).
- FIX 3: _fix_pandas_compatibility() is now actually called before exec().
"""

# ---------------------------------------------------
# IMPORTS
# ---------------------------------------------------

import pandas as pd
import json
import os
import re

try:
    from huggingface_hub import InferenceClient
except ImportError as exc:
    raise ImportError(
        "huggingface_hub is required. Install with `pip install huggingface-hub`."
    ) from exc

from analytics.performance_analysis import generate_metric_view

# ---------------------------------------------------
# HF CONFIG
# ---------------------------------------------------

HF_MODEL_ID = os.environ.get("HF_MODEL_ID", "Qwen/Qwen2.5-7B-Instruct")
HF_TOKEN = os.environ.get("HUGGINGFACE_API_TOKEN")


# ---------------------------------------------------
# HELPER: GET INFERENCE CLIENT
# ---------------------------------------------------

def _get_hf_client():
    if not HF_TOKEN:
        raise RuntimeError(
            "HUGGINGFACE_API_TOKEN is required. Set it in your environment."
        )
    return InferenceClient(token=HF_TOKEN)


# ---------------------------------------------------
# HELPER: EXTRACT JSON FROM LLM RESPONSE
# ---------------------------------------------------

def _extract_json(text: str):
    match = re.search(r"\{.*\}", text, re.S)
    if not match:
        return None
    payload = match.group(0)
    try:
        return json.loads(payload)
    except json.JSONDecodeError:
        try:
            cleaned = re.sub(r"[\n\r]+", " ", payload)
            cleaned = re.sub(r"(['\"])?([a-zA-Z0-9_]+)(['\"])?\s*:\s*", r'"\2": ', cleaned)
            return json.loads(cleaned)
        except Exception:
            return None


# ---------------------------------------------------
# HELPER: FIX COMMON PANDAS COMPATIBILITY ISSUES
# ---------------------------------------------------

def _fix_pandas_compatibility(code: str) -> str:
    """
    Fix common pandas API compatibility issues in generated code.
    Handles version differences between pandas versions.
    """
    # Fix: .reset_index(name=...) -> .reset_index(names=[...])
    code = re.sub(
        r"\.reset_index\(name=(['\"])([^'\"]+)\1\)",
        r".reset_index(names=[\1\2\1])",
        code
    )

    # Fix: .reset_index(name= with variable
    code = re.sub(
        r"\.reset_index\(name=([a-zA-Z_][a-zA-Z0-9_]*)\)",
        r".reset_index(names=[\1])",
        code
    )

    # Fix: df.append() deprecated in newer pandas -> pd.concat()
    code = re.sub(
        r"(\w+)\.append\((\w+),\s*ignore_index=True\)",
        r"pd.concat([\1, \2], ignore_index=True)",
        code
    )

    return code


# ---------------------------------------------------
# STEP 1: CODE GENERATION
# ---------------------------------------------------

def generate_analysis_requirements(
    question: str,
    acq: pd.DataFrame,
    perf: pd.DataFrame,
    master_df: pd.DataFrame
):
    """
    LLM breaks down question into 1-3 structured analytics requirements.
    Each requirement includes a description and executable pandas code.
    """

    client = _get_hf_client()

    # Build detailed column descriptions
    acq_cols = {
        "account_id": "unique account identifier",
        "booking_date": "when account was originated",
        "booking_vintage": "year-month of origination (YYYY-MM)",
        "fico_band": "FICO score bracket (e.g., 700-750, 750-800)",
        "sourcing_channel": "acquisition channel (e.g., Online, Branch, Broker)",
        "city_tier": "city classification (Tier-1, Tier-2, Tier-3)",
        "occupation_type": "borrower occupation category",
        "credit_limit": "approved credit line amount"
    }

    perf_cols = {
        "account_id": "unique account identifier",
        "reporting_month": "month of performance observation (YYYY-MM)",
        "mob": "months on books (age of account in months)",
        "dpd": "days past due (0, 30, 60, 90+)",
        "balance": "current outstanding balance",
        "ncl_amount": "net charge-off amount (dollars)",
        "payment": "payment amount in period"
    }

    prompt = (
        "You are a senior retail credit risk analyst with 15+ years of portfolio management experience.\n\n"
        "Your task:\n"
        "1. Analyze the user's analytical question deeply\n"
        "2. Determine 1-3 specific analytics requirements needed to fully answer the question\n"
        "3. For EACH requirement, generate executable pandas code\n"
        "4. Return ONLY valid JSON, no other text\n\n"

        "AVAILABLE DATA:\n"
        "- acq: acquisition data with columns: " + ", ".join(acq_cols.keys()) + "\n"
        "- perf: performance data with columns: " + ", ".join(perf_cols.keys()) + "\n"
        "- master_df: merged acq+perf, includes all above columns\n\n"

        "COLUMN DESCRIPTIONS:\n"
        "Acquisition (acq):\n"
        + "\n".join([f" - {k}: {v}" for k, v in acq_cols.items()]) + "\n\n"
        "Performance (perf):\n"
        + "\n".join([f" - {k}: {v}" for k, v in perf_cols.items()]) + "\n\n"

        "Available Risk Metrics via generate_metric_view(df, metric_name, group_col):\n"
        " - 30+@3 (30+ dpd at 3 months)\n"
        " - 30+@6 (30+ dpd at 6 months)\n"
        " - 60+@6 (60+ dpd at 6 months)\n"
        " - Yr1 NCL (Year 1 net charge-off rate)\n\n"

        "CODE GENERATION RULES:\n"
        "- Generate pandas code ONLY\n"
        "- IMPORTANT: Always store your final result in a variable named exactly 'result_1', 'result_2', or 'result_3' matching the sequence number\n"
        "- Use meaningful intermediate variable names (e.g., vintage_analysis, segment_summary)\n"
        "- Focus on GROUP BY aggregations for insights\n"
        "- Calculate rates as dollars/total (percentage)\n"
        "- Sort by risk metrics (descending) to identify worst segments\n"
        "- Add brief comments for clarity\n"
        "- NO markdown, NO explanations outside JSON\n\n"

        "JSON STRUCTURE:\n"
        "{\n"
        ' "requirements": [\n'
        '   {\n'
        '     "sequence": 1,\n'
        '     "title": "Analysis title",\n'
        '     "description": "What this code does and why it matters",\n'
        '     "code": "pandas code here — must assign final result to result_1"\n'
        "   }\n"
        " ]\n"
        "}\n\n"

        "User Question:\n" + question
    )

    messages = [
        {
            "role": "system",
            "content": (
                "You are a senior credit risk analyst who generates pandas code for portfolio analytics. "
                "Return ONLY valid JSON. Always store the final result in result_1, result_2, or result_3."
            )
        },
        {"role": "user", "content": prompt}
    ]

    response = client.chat.completions.create(
        model=HF_MODEL_ID,
        messages=messages,
        max_tokens=2048,
        temperature=0.1,
        top_p=0.95
    )

    response_text = (
        response.choices[0].message.content
        if hasattr(response, "choices")
        else str(response)
    )

    # Extract JSON
    spec = _extract_json(response_text)

    if not spec:
        return {
            "success": False,
            "requirements": [],
            "error": f"Failed to parse JSON from LLM response: {response_text[:200]}",
            "raw_response": response_text
        }

    requirements = spec.get("requirements", [])

    if not requirements:
        return {
            "success": False,
            "requirements": [],
            "error": f"LLM returned no requirements. Response keys: {list(spec.keys())}",
            "raw_response": response_text[:300]
        }

    print(f"[DEBUG] Generated {len(requirements)} requirements for question: {question[:80]}")
    for i, req in enumerate(requirements, 1):
        print(f"  Req {i}: {req.get('title')}")

    return {
        "success": True,
        "requirements": requirements,
        "error": None
    }


# ---------------------------------------------------
# STEP 2: CODE EXECUTION (LOOPED)
# ---------------------------------------------------

def execute_requirement_code(
    code: str,
    acq: pd.DataFrame,
    perf: pd.DataFrame,
    master_df: pd.DataFrame,
    requirement_num: int
):
    """
    Safely execute generated pandas code for a single requirement.

    FIXES:
    - FIX 1: Single namespace dict passed to exec() so variable assignments
             are reliably captured (Python quirk with separate globals/locals).
    - FIX 2: Smart result detection — checks named keys first, then scans
             for any new DataFrame/Series, then any non-None new variable.
    - FIX 3: _fix_pandas_compatibility() called before exec().
    """

    # FIX 3: Apply pandas compatibility patches BEFORE executing
    code = _fix_pandas_compatibility(code)

    # FIX 1: Merge everything into ONE dict so exec() writes back correctly.
    # When you pass separate globals + locals to exec(), Python's bytecode
    # compiler uses STORE_FAST which writes to an internal frame and does NOT
    # update the locals dict you passed in — so result variables always come
    # back None. Using a single namespace avoids this entirely.
    namespace = {
        "pd": pd,
        "generate_metric_view": generate_metric_view,
        "__builtins__": __builtins__,
        # Data available to generated code
        "acq": acq,
        "perf": perf,
        "master_df": master_df,
    }

    # Snapshot of keys before exec so we can detect newly created variables
    keys_before = set(namespace.keys())

    try:
        print(f"[DEBUG] Executing requirement {requirement_num}...")
        print(f"[DEBUG] Code preview: {code[:120].strip()}...")

        exec(code, namespace)  # FIX 1: single namespace

        # FIX 2: Smart result detection — three priority tiers

        # --- Tier 1: expected named result variables ---
        result = None
        expected_keys = [
            f"result_{requirement_num}",
            "final_result",
            "result",
        ]
        for key in expected_keys:
            if key in namespace and namespace[key] is not None:
                result = namespace[key]
                print(f"[DEBUG] Found result in expected variable: '{key}'")
                break

        # --- Tier 2: any NEW DataFrame or Series created during exec ---
        if result is None:
            new_keys = set(namespace.keys()) - keys_before
            for key in new_keys:
                val = namespace[key]
                if isinstance(val, (pd.DataFrame, pd.Series)) and val is not None:
                    result = val
                    print(f"[DEBUG] Found result by scanning new DataFrame/Series: '{key}'")
                    break

        # --- Tier 3: any new non-None, non-private variable ---
        if result is None:
            new_keys = set(namespace.keys()) - keys_before
            for key in sorted(new_keys):  # sorted for determinism
                if key.startswith("_"):
                    continue
                val = namespace[key]
                if val is not None:
                    result = val
                    print(f"[DEBUG] Fallback: found result in new variable: '{key}'")
                    break

        if result is None:
            result = "Code executed successfully but no result variable was found in namespace."

        print(f"[DEBUG] Req {requirement_num} success. Result type: {type(result).__name__}")
        return {
            "success": True,
            "result": result,
            "error": None
        }

    except Exception as e:
        import traceback
        tb = traceback.format_exc()
        print(f"[DEBUG] Req {requirement_num} FAILED: {str(e)}")
        print(f"[DEBUG] Traceback:\n{tb}")
        return {
            "success": False,
            "result": None,
            "error": str(e)
        }


def execute_all_requirements(
    requirements: list,
    acq: pd.DataFrame,
    perf: pd.DataFrame,
    master_df: pd.DataFrame
):
    """
    Execute all requirements sequentially, building context.
    """

    print(f"[DEBUG] Starting execution of {len(requirements)} requirements")
    all_results = []
    context_text = ""

    for i, req in enumerate(requirements, 1):
        code = req.get("code", "")
        description = req.get("description", "")
        title = req.get("title", f"Analysis {i}")

        exec_result = execute_requirement_code(code, acq, perf, master_df, i)

        all_results.append({
            "sequence": i,
            "title": title,
            "description": description,
            "code": code,
            # "success" is what app.py checks via res.get("success")
            # "execution_success" kept for backward compatibility
            "success": exec_result["success"],
            "execution_success": exec_result["success"],
            "result": exec_result["result"],
            "error": exec_result.get("error")
        })

        # Build context for interpretation
        if exec_result["success"]:
            context_text += f"\nAnalysis {i} ({title}):\n{str(exec_result['result'])}\n"
        else:
            context_text += f"\nAnalysis {i} ({title}) FAILED:\n{exec_result['error']}\n"

    return all_results, context_text


# ---------------------------------------------------
# STEP 3: RESULT INTERPRETATION
# ---------------------------------------------------

def interpret_all_results(
    question: str,
    all_results: list,
    context_text: str
):
    """
    Senior risk analyst LLM interprets all results holistically.
    """

    print(f"[DEBUG] Interpreting results for {len(all_results)} analyses")
    print(f"[DEBUG] Successful executions: {sum(1 for r in all_results if r.get('success'))}")

    client = _get_hf_client()

    # Format all analyses
    analyses_text = ""
    for res in all_results:
        analyses_text += f"\n{'=' * 60}\n"
        analyses_text += f"Analysis {res['sequence']}: {res['title']}\n"
        analyses_text += f"Description: {res['description']}\n"
        analyses_text += f"{'=' * 60}\n"
        if res["success"]:
            analyses_text += f"Result:\n{str(res['result'])}\n"
        else:
            analyses_text += f"Execution Error: {res['error']}\n"

    prompt = (
        "You are a senior retail credit risk analyst with 15+ years of portfolio management experience.\n\n"
        "Your task:\n"
        "Synthesize the analytical results and provide comprehensive risk insights.\n\n"

        "Focus on:\n"
        "- Key findings and patterns across all analyses\n"
        "- Risk deterioration or improvement trends\n"
        "- Vintage/segment concentration issues and implications\n"
        "- Root causes of observed patterns\n"
        "- Unusual trends, anomalies, or red flags\n"
        "- Actionable recommendations for portfolio management\n"
        "- Comparative risk assessment (which segments/vintages are most/least risky)\n\n"

        "Guidelines:\n"
        "- Be analytical and specific (not generic)\n"
        "- Focus on business implications, not just statistics\n"
        "- Avoid repeating raw tables; interpret the meaning\n"
        "- Provide 3-5 key insights\n"
        "- Suggest next investigative steps if needed\n\n"

        "User's Original Question:\n" + question + "\n\n"

        "Analyses Performed:\n" + analyses_text + "\n\n"

        "Provide your senior analyst interpretation:"
    )

    messages = [
        {
            "role": "system",
            "content": "You are a senior credit risk analyst providing executive insights from portfolio analytics."
        },
        {"role": "user", "content": prompt}
    ]

    response = client.chat.completions.create(
        model=HF_MODEL_ID,
        messages=messages,
        max_tokens=1024,
        temperature=0.3,
        top_p=0.95
    )

    interpretation = (
        response.choices[0].message.content
        if hasattr(response, "choices")
        else str(response)
    )
    return interpretation


# ---------------------------------------------------
# MASTER ORCHESTRATOR FUNCTION
# ---------------------------------------------------

def run_deep_dive_analysis(
    question: str,
    acq: pd.DataFrame,
    perf: pd.DataFrame,
    master_df: pd.DataFrame
):
    """
    End-to-end deep dive analysis:
    1. Break question into 1-3 structured requirements
    2. Generate code for each requirement
    3. Execute each requirement's code sequentially
    4. Synthesize results and provide senior analyst interpretation
    """

    print(f"\n[DEEP DIVE START] Question: {question}")
    print(f"[DEBUG] Data shapes - Acq: {acq.shape}, Perf: {perf.shape}, Master: {master_df.shape}")

    # Step 1: Generate requirements
    print("[DEBUG] Step 1: Generating requirements...")
    req_response = generate_analysis_requirements(question, acq, perf, master_df)

    if not req_response["success"]:
        return {
            "success": False,
            "question": question,
            "requirements": [],
            "all_results": [],
            "interpretation": f"Failed to generate requirements: {req_response['error']}",
            "error": req_response["error"]
        }

    requirements = req_response["requirements"][:3]  # Cap at 3

    # Step 2 & 3: Execute all requirements
    print(f"[DEBUG] Step 2-3: Executing {len(requirements)} requirements...")
    all_results, context_text = execute_all_requirements(requirements, acq, perf, master_df)

    # Step 4: Interpret results
    print("[DEBUG] Step 4: Interpreting all results...")
    interpretation = interpret_all_results(question, all_results, context_text)
    print("[DEEP DIVE END] Analysis complete\n")

    return {
        "success": True,
        "question": question,
        "requirements": requirements,
        "all_results": all_results,
        "interpretation": interpretation,
        "error": None
    }