import streamlit as st
import pandas as pd
import numpy as np
import re
import httpx
import json
import os
import time
import logging
from typing import Optional, List
from openai import OpenAI

import textgrad as tg
from st_aggrid import AgGrid, GridOptionsBuilder, GridUpdateMode, DataReturnMode

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# --- Page Configuration ---
st.set_page_config(
    layout="wide",
    page_title="TextGrad Regex Optimizer",
    page_icon="📝",
    initial_sidebar_state="expanded"
)

# --- Session State Initialization ---
DEFAULT_STATE = {
    'dataset': None,
    'selected_indices': [],  # Track selected row indices for training
    'optimized_prompt': None,
    'optimization_history': [],
    'config': {
        'model_name': 'gpt-4o-mini',
        'critic_model': 'gpt-4o',
        'api_key': '',
        'base_url': 'https://api.openai.com/v1',
        'timeout': 30,
        'max_retries': 3,
        'temperature': 0.7,
        'max_tokens': 1024,
    },
    'textgrad_config': {
        'num_iterations': 5,
        'batch_size': 3,
        'early_stopping_threshold': 0.95,
    },
    'prompts': {
        'system_instruction': "You are a Regex Expert. Given the input text, provide a high-precision Python regex pattern to extract the target text. Output only the regex pattern, nothing else.",
        'output_description': "A Python-compatible regular expression",
    },
    'train_test_split': 0.8,
    'regex_flags': [],
}

for key, value in DEFAULT_STATE.items():
    if key not in st.session_state:
        st.session_state[key] = value


# --- Configuration Manager ---
class ConfigManager:
    """Manages application configuration with persistence."""
    
    CONFIG_FILE = "textgrad_config.json"
    
    @staticmethod
    def save_config():
        """Save current configuration to file."""
        config_data = {
            'config': st.session_state.config,
            'textgrad_config': st.session_state.textgrad_config,
            'prompts': st.session_state.prompts,
            'train_test_split': st.session_state.train_test_split,
            'regex_flags': st.session_state.regex_flags,
        }
        try:
            with open(ConfigManager.CONFIG_FILE, 'w') as f:
                json.dump(config_data, f, indent=2)
            return True
        except Exception as e:
            st.error(f"Failed to save config: {e}")
            return False
    
    @staticmethod
    def load_config():
        """Load configuration from file."""
        try:
            if os.path.exists(ConfigManager.CONFIG_FILE):
                with open(ConfigManager.CONFIG_FILE, 'r') as f:
                    config_data = json.load(f)
                for key, value in config_data.items():
                    if key in st.session_state:
                        if isinstance(value, dict):
                            st.session_state[key].update(value)
                        else:
                            st.session_state[key] = value
                return True
        except Exception as e:
            st.warning(f"Failed to load config: {e}")
        return False
    
    @staticmethod
    def reset_to_defaults():
        """Reset all configuration to defaults."""
        for key, value in DEFAULT_STATE.items():
            if key not in ['dataset', 'optimized_prompt', 'optimization_history']:
                st.session_state[key] = value.copy() if isinstance(value, (dict, list)) else value


# --- TextGrad Setup ---
def setup_textgrad() -> bool:
    """Configure TextGrad with current settings."""
    config = st.session_state.config
    try:
        api_key = config['api_key'] or os.getenv("OPENAI_API_KEY", "")
        if not api_key:
            st.error("Please provide an OpenAI API key.")
            return False
        
        os.environ["OPENAI_API_KEY"] = api_key
        
        # Get engines
        target_engine = tg.get_engine(config['model_name'])
        critic_engine = tg.get_engine(config['critic_model'])
        tg.set_backward_engine(critic_engine)
        
        st.session_state['target_engine'] = target_engine
        st.session_state['critic_engine'] = critic_engine
        
        return True
    except Exception as e:
        st.error(f"TextGrad Configuration Error: {e}")
        return False


# --- TextGrad Model Wrapper ---
class RegexGeneratorModel:
    """TextGrad model wrapper for regex generation task."""
    
    def __init__(self, system_prompt: tg.Variable, engine):
        self.system_prompt = system_prompt
        self.llm_engine = engine
        self.model = tg.BlackboxLLM(engine=engine, system_prompt=system_prompt)
    
    def __call__(self, user_message: tg.Variable) -> tg.Variable:
        """Forward pass through the LLM with current system prompt."""
        return self.model(user_message)
    
    def parameters(self):
        """Return parameters for the optimizer."""
        return [self.system_prompt]


# --- Loss Function ---
def create_regex_loss_fn(raw_text: str, target: str, regex_flags: list) -> tg.TextLoss:
    """
    Create a TextGrad loss function that evaluates regex quality.
    Returns textual feedback that guides optimization.
    """
    flags_str = ", ".join(regex_flags) if regex_flags else "None"
    
    evaluation_instruction = f"""Evaluate the quality of this regex pattern for extracting specific text.

Input Text: {raw_text[:500]}{'...' if len(raw_text) > 500 else ''}
Target Text to Extract: {target}
Regex Flags Applied: {flags_str}

Evaluation Criteria:
1. Does the regex pattern correctly extract the target text from the input?
2. Is the pattern precise (not too broad, capturing extra text)?
3. Is the pattern syntax valid for Python's re module?
4. Is the pattern robust (handles edge cases appropriately)?

Provide specific, actionable feedback on how to improve the system prompt to generate better regex patterns.
Focus on:
- What instructions would help generate more precise patterns
- How to avoid common regex mistakes
- Ways to improve pattern matching accuracy
Be constructive and specific about what changes would improve performance."""

    return tg.TextLoss(evaluation_instruction)


# --- Simple Metric ---
def evaluate_regex_simple(pattern: str, raw_text: str, target: str, flags: list) -> float:
    """
    Simple scoring function for regex evaluation.
    Returns a score between 0 and 1.
    """
    if not pattern:
        return 0.0
    
    # Compile flags
    compiled_flags = 0
    for flag in flags:
        compiled_flags |= getattr(re, flag, 0)
    
    try:
        compiled = re.compile(pattern.strip(), compiled_flags)
    except re.error:
        return 0.0
    
    match = compiled.search(raw_text)
    if not match:
        return 0.0
    
    extracted = match.group(0)
    
    if extracted == target:
        return 1.0
    elif target in extracted:
        # Too broad - partial credit
        return 0.3
    elif extracted in target:
        # Too narrow - partial credit
        return 0.3
    else:
        return 0.1


# --- Sidebar Configuration ---
def render_sidebar():
    """Render the configuration sidebar."""
    with st.sidebar:
        st.title("⚙️ Configuration")
        
        # Config management buttons
        col1, col2, col3 = st.columns(3)
        with col1:
            if st.button("💾 Save", use_container_width=True):
                if ConfigManager.save_config():
                    st.success("Saved!")
        with col2:
            if st.button("📂 Load", use_container_width=True):
                if ConfigManager.load_config():
                    st.success("Loaded!")
                    st.rerun()
        with col3:
            if st.button("🔄 Reset", use_container_width=True):
                ConfigManager.reset_to_defaults()
                st.rerun()
        
        st.divider()
        
        # LLM Configuration
        with st.expander("🤖 LLM Settings", expanded=True):
            st.session_state.config['model_name'] = st.text_input(
                "Target Model",
                value=st.session_state.config['model_name'],
                help="Model to optimize (e.g., gpt-4o-mini)"
            )
            
            st.session_state.config['critic_model'] = st.text_input(
                "Critic Model",
                value=st.session_state.config['critic_model'],
                help="Model for generating gradients (e.g., gpt-4o)"
            )
            
            st.session_state.config['api_key'] = st.text_input(
                "API Key",
                value=st.session_state.config['api_key'],
                type="password",
                help="Leave empty to use OPENAI_API_KEY env var"
            )
            
            st.session_state.config['base_url'] = st.text_input(
                "Base URL",
                value=st.session_state.config['base_url'],
                help="Custom API endpoint"
            )
            
            col1, col2 = st.columns(2)
            with col1:
                st.session_state.config['timeout'] = st.number_input(
                    "Timeout (s)",
                    min_value=5,
                    max_value=300,
                    value=st.session_state.config['timeout']
                )
            with col2:
                st.session_state.config['max_retries'] = st.number_input(
                    "Max Retries",
                    min_value=0,
                    max_value=10,
                    value=st.session_state.config['max_retries']
                )
            
            col1, col2 = st.columns(2)
            with col1:
                st.session_state.config['temperature'] = st.slider(
                    "Temperature",
                    min_value=0.0,
                    max_value=2.0,
                    value=st.session_state.config['temperature'],
                    step=0.1
                )
            with col2:
                st.session_state.config['max_tokens'] = st.number_input(
                    "Max Tokens",
                    min_value=64,
                    max_value=8192,
                    value=st.session_state.config['max_tokens']
                )
        
        # TextGrad Optimizer Settings
        with st.expander("📝 TextGrad Optimizer", expanded=False):
            st.session_state.textgrad_config['num_iterations'] = st.slider(
                "Iterations",
                min_value=1,
                max_value=20,
                value=st.session_state.textgrad_config['num_iterations'],
                help="Number of optimization iterations"
            )
            
            st.session_state.textgrad_config['batch_size'] = st.slider(
                "Batch Size",
                min_value=1,
                max_value=10,
                value=st.session_state.textgrad_config['batch_size'],
                help="Number of examples per batch"
            )
            
            st.session_state.textgrad_config['early_stopping_threshold'] = st.slider(
                "Early Stopping Threshold",
                min_value=0.5,
                max_value=1.0,
                value=st.session_state.textgrad_config['early_stopping_threshold'],
                step=0.05,
                help="Stop if this score is reached"
            )
        
        # Prompt Configuration
        with st.expander("📝 Prompts", expanded=False):
            st.session_state.prompts['system_instruction'] = st.text_area(
                "System Instruction",
                value=st.session_state.prompts['system_instruction'],
                height=150,
                help="Initial system prompt for regex generation"
            )
            
            st.session_state.prompts['output_description'] = st.text_input(
                "Output Field Description",
                value=st.session_state.prompts['output_description'],
                help="Description for the regex output field"
            )
        
        # Regex Configuration
        with st.expander("🔧 Regex Options", expanded=False):
            flag_options = ['IGNORECASE', 'MULTILINE', 'DOTALL', 'VERBOSE', 'ASCII']
            st.session_state.regex_flags = st.multiselect(
                "Regex Flags",
                options=flag_options,
                default=st.session_state.regex_flags,
                help="Python regex flags to apply"
            )
        
        # Data Split Configuration
        with st.expander("📊 Data Settings", expanded=False):
            st.session_state.train_test_split = st.slider(
                "Train/Validation Split",
                min_value=0.5,
                max_value=0.95,
                value=st.session_state.train_test_split,
                step=0.05,
                help="Proportion of data for training"
            )


# --- Stratified Sampling Utility ---
def stratified_train_val_split(
    df: pd.DataFrame,
    train_ratio: float = 0.8,
    stratify_column: str = 'ground_truth',
    random_state: int = 42
) -> tuple:
    """
    Perform stratified train/validation split.
    Groups samples by ground_truth pattern and splits proportionally.
    """
    np.random.seed(random_state)
    
    df = df.copy()
    df['_strat_key'] = df[stratify_column].apply(
        lambda x: str(x)[:50] if pd.notna(x) and x != '' else '_empty_'
    )
    
    train_indices = []
    val_indices = []
    
    for _, group in df.groupby('_strat_key'):
        indices = group.index.tolist()
        np.random.shuffle(indices)
        
        split_idx = max(1, int(len(indices) * train_ratio))
        
        if len(indices) > 1 and split_idx == len(indices):
            split_idx = len(indices) - 1
        
        train_indices.extend(indices[:split_idx])
        val_indices.extend(indices[split_idx:])
    
    train_df = df.loc[train_indices].drop(columns=['_strat_key'])
    val_df = df.loc[val_indices].drop(columns=['_strat_key']) if val_indices else pd.DataFrame()
    
    return train_df, val_df


# --- Data Persistence ---
def save_annotated_data(df: pd.DataFrame, selected_indices: List[int], filepath: str) -> bool:
    """Save annotated data with selection state."""
    try:
        save_df = df.copy()
        save_df['_selected'] = save_df.index.isin(selected_indices)
        
        if filepath.endswith('.json'):
            save_df.to_json(filepath, orient='records', indent=2)
        else:
            save_df.to_csv(filepath, index=False)
        return True
    except Exception as e:
        st.error(f"Failed to save data: {e}")
        return False


def load_annotated_data(filepath: str) -> tuple:
    """Load annotated data with selection state."""
    try:
        df = pd.read_csv(filepath)
        
        selected_indices = []
        if '_selected' in df.columns:
            selected_indices = df[df['_selected'] == True].index.tolist()
            df = df.drop(columns=['_selected'])
        
        if 'text' not in df.columns:
            raise ValueError("Dataset must have a 'text' column.")
        
        if 'ground_truth' not in df.columns:
            df['ground_truth'] = ''
        
        return df, selected_indices
    except Exception as e:
        st.error(f"Failed to load data: {e}")
        return None, []


# --- Main Application Tabs ---
def render_data_ingestion_tab():
    """Render the data ingestion tab."""
    st.header("📥 Data Ingestion & Annotation")
    
    col1, col2 = st.columns([2, 1])
    
    with col1:
        uploaded = st.file_uploader(
            "Upload Dataset",
            type=["csv", "json", "xlsx"],
            help="CSV/JSON/Excel with 'text' column (ground_truth optional, _selected for pre-selected rows)"
        )
    
    with col2:
        st.markdown("**Expected Format:**")
        st.code("text,ground_truth,_selected\n'Sample text','expected',true", language="csv")
    
    if uploaded:
        try:
            df, selected_indices = load_annotated_data(uploaded)
            if df is not None:
                st.session_state.dataset = df.reset_index(drop=True)
                st.session_state.selected_indices = selected_indices
                st.success(f"✅ Loaded {len(df)} samples ({len(selected_indices)} pre-selected)")
        except Exception as e:
            st.error(f"Failed to load file: {e}")
            return
    
    if st.session_state.dataset is not None:
        df = st.session_state.dataset.copy()
        
        st.subheader("📝 Annotate Ground Truth")
        st.caption("Edit 'ground_truth' column and select rows (checkbox) to include in training/validation.")
        
        pre_selected_rows = st.session_state.get('selected_indices', [])
        
        # Configure AgGrid
        gb = GridOptionsBuilder.from_dataframe(df)
        gb.configure_default_column(
            resizable=True,
            filterable=True,
            sortable=True
        )
        gb.configure_column(
            "text",
            width=500,
            wrapText=True,
            autoHeight=True,
            editable=False
        )
        gb.configure_column(
            "ground_truth",
            editable=True,
            width=300,
            cellStyle={'backgroundColor': '#fffde7'}
        )
        gb.configure_selection(
            selection_mode='multiple',
            use_checkbox=True,
            pre_selected_rows=pre_selected_rows
        )
        gb.configure_pagination(paginationAutoPageSize=False, paginationPageSize=10)
        
        grid_response = AgGrid(
            df,
            gridOptions=gb.build(),
            update_mode=GridUpdateMode.MODEL_CHANGED | GridUpdateMode.SELECTION_CHANGED,
            data_return_mode=DataReturnMode.FILTERED_AND_SORTED,
            fit_columns_on_grid_load=False,
            theme='streamlit',
            height=400,
            key='annotation_grid'
        )
        
        st.session_state.dataset = pd.DataFrame(grid_response['data'])
        
        selected_rows = grid_response.get('selected_rows', [])
        if selected_rows is not None and len(selected_rows) > 0:
            selected_df = pd.DataFrame(selected_rows)
            if not selected_df.empty:
                st.session_state.selected_indices = selected_df.index.tolist()
        else:
            st.session_state.selected_indices = []
        
        st.divider()
        
        # Save/Export section
        st.subheader("💾 Save Annotated Data")
        col1, col2, col3 = st.columns([2, 1, 1])
        
        with col1:
            save_filename = st.text_input(
                "Filename",
                value="annotated_data.csv",
                help="Enter filename (.csv or .json)"
            )
        
        with col2:
            if st.button("💾 Save to File", use_container_width=True):
                if save_annotated_data(
                    st.session_state.dataset,
                    st.session_state.selected_indices,
                    save_filename
                ):
                    st.success(f"✅ Saved to {save_filename}")
        
        with col3:
            save_df = st.session_state.dataset.copy()
            save_df['_selected'] = save_df.index.isin(st.session_state.selected_indices)
            
            csv_data = save_df.to_csv(index=False)
            st.download_button(
                "📥 Download CSV",
                csv_data,
                file_name="annotated_data.csv",
                mime="text/csv",
                use_container_width=True
            )
        
        st.divider()
        
        # Data statistics
        st.subheader("📊 Data Statistics")
        
        total = len(st.session_state.dataset)
        annotated = (st.session_state.dataset['ground_truth'].astype(str) != '').sum()
        selected_count = len(st.session_state.selected_indices)
        
        selected_df = st.session_state.dataset.iloc[st.session_state.selected_indices] if st.session_state.selected_indices else pd.DataFrame()
        selected_annotated = selected_df[selected_df['ground_truth'].astype(str) != ''] if not selected_df.empty else pd.DataFrame()
        
        if len(selected_annotated) >= 2:
            train_df, val_df = stratified_train_val_split(
                selected_annotated,
                train_ratio=st.session_state.train_test_split
            )
            train_size = len(train_df)
            val_size = len(val_df)
        else:
            train_size = 0
            val_size = 0
        
        col1, col2, col3, col4 = st.columns(4)
        
        with col1:
            st.metric("Total Samples", total)
        with col2:
            st.metric("Annotated", f"{annotated}/{total}")
        with col3:
            st.metric("Selected", selected_count, help="Rows selected for training/validation")
        with col4:
            st.metric("Train/Val", f"{train_size}/{val_size}", help="Stratified split of selected & annotated rows")
        
        if selected_count == 0:
            st.info("💡 Select rows using checkboxes to include them in training/validation.")
        elif len(selected_annotated) < 2:
            st.warning("⚠️ Please select at least 2 annotated rows for training.")
        
        if len(selected_annotated) >= 2:
            with st.expander("📈 Stratification Preview"):
                pattern_counts = selected_annotated['ground_truth'].apply(
                    lambda x: str(x)[:30] + '...' if len(str(x)) > 30 else str(x)
                ).value_counts()
                
                st.markdown("**Ground Truth Pattern Distribution:**")
                st.bar_chart(pattern_counts)
                
                st.caption(f"Training: {train_size} samples, Validation: {val_size} samples")
        
        with st.expander("📋 Sample Preview"):
            st.dataframe(
                st.session_state.dataset.head(5),
                use_container_width=True
            )


def render_optimization_tab():
    """Render the optimization tab."""
    st.header("📝 TextGrad Optimization")
    
    if st.session_state.dataset is None:
        st.warning("⚠️ Please upload and annotate data first.")
        return
    
    df = st.session_state.dataset
    selected_indices = st.session_state.get('selected_indices', [])
    
    if selected_indices:
        selected_df = df.iloc[selected_indices]
        annotated_df = selected_df[selected_df['ground_truth'].astype(str) != '']
        use_selection = True
    else:
        annotated_df = df[df['ground_truth'].astype(str) != '']
        use_selection = False
    
    if len(annotated_df) < 2:
        if use_selection:
            st.warning("⚠️ Please select and annotate at least 2 samples in the Data Ingestion tab.")
        else:
            st.warning("⚠️ Please annotate at least 2 samples or select rows for training.")
        return
    
    # Stratified split
    train_df, val_df = stratified_train_val_split(
        annotated_df,
        train_ratio=st.session_state.train_test_split
    )
    
    col1, col2, col3 = st.columns(3)
    with col1:
        st.info(f"📚 Training samples: {len(train_df)}")
    with col2:
        st.info(f"🧪 Validation samples: {len(val_df)}")
    with col3:
        if use_selection:
            st.success("✅ Using selected rows")
        else:
            st.warning("⚠️ Using all annotated rows")
    
    # Optimization controls
    col1, col2, col3 = st.columns([1, 1, 2])
    
    with col1:
        run_button = st.button(
            "🚀 Run Optimization",
            type="primary",
            use_container_width=True
        )
    
    with col2:
        if st.button("🔄 Reset Results", use_container_width=True):
            st.session_state.optimized_prompt = None
            st.session_state.optimization_history = []
            st.rerun()
    
    if run_button:
        if not setup_textgrad():
            return
        
        # Prepare training examples
        train_examples = [
            {'raw_text': row['text'], 'ground_truth': row['ground_truth']}
            for _, row in train_df.iterrows()
        ]
        
        val_examples = [
            {'raw_text': row['text'], 'ground_truth': row['ground_truth']}
            for _, row in val_df.iterrows()
        ]
        
        # Progress tracking
        progress_bar = st.progress(0)
        status_text = st.empty()
        iteration_log = st.empty()
        
        try:
            with st.spinner("📝 TextGrad is optimizing the prompt..."):
                status_text.text("Initializing TextGrad...")
                
                # Initialize system prompt as a TextGrad Variable (trainable)
                system_prompt = tg.Variable(
                    st.session_state.prompts['system_instruction'],
                    requires_grad=True,
                    role_description="system prompt for regex generation that guides the LLM to extract target text using precise Python regex patterns"
                )
                
                # Initialize model
                model = RegexGeneratorModel(
                    system_prompt, 
                    st.session_state['target_engine']
                )
                
                # Initialize TextGrad optimizer (TGD - Textual Gradient Descent)
                optimizer = tg.TGD(parameters=[system_prompt])
                
                progress_bar.progress(10)
                status_text.text("Evaluating initial performance...")
                
                # Evaluate initial performance
                initial_scores = []
                for example in val_examples[:5]:
                    try:
                        user_msg = tg.Variable(
                            f"Extract the target text from the following input:\n\n{example['raw_text']}",
                            requires_grad=False,
                            role_description="user input for regex extraction"
                        )
                        prediction = model(user_msg)
                        score = evaluate_regex_simple(
                            prediction.value.strip(),
                            example['raw_text'],
                            example['ground_truth'],
                            st.session_state.regex_flags
                        )
                        initial_scores.append(score)
                    except Exception as e:
                        logger.warning(f"Error in initial eval: {e}")
                        initial_scores.append(0.0)
                
                initial_avg = np.mean(initial_scores) if initial_scores else 0.0
                
                best_score = initial_avg
                best_prompt = system_prompt.value
                history = []
                
                num_iterations = st.session_state.textgrad_config['num_iterations']
                batch_size = st.session_state.textgrad_config['batch_size']
                
                progress_bar.progress(20)
                status_text.text(f"Starting optimization (Initial score: {initial_avg:.2%})...")
                
                # TextGrad optimization loop
                for iteration in range(num_iterations):
                    status_text.text(f"Iteration {iteration + 1}/{num_iterations}")
                    
                    # Sample training examples for this iteration
                    batch_indices = np.random.choice(
                        len(train_examples),
                        min(batch_size, len(train_examples)),
                        replace=False
                    )
                    
                    iteration_losses = []
                    
                    for idx in batch_indices:
                        example = train_examples[idx]
                        
                        try:
                            # Clear gradients
                            optimizer.zero_grad()
                            
                            # Create user message variable
                            user_msg = tg.Variable(
                                f"Extract the target text from the following input:\n\n{example['raw_text']}",
                                requires_grad=False,
                                role_description="user input for regex extraction"
                            )
                            
                            # Forward pass
                            prediction = model(user_msg)
                            
                            # Create loss function for this example
                            loss_fn = create_regex_loss_fn(
                                example['raw_text'],
                                example['ground_truth'],
                                st.session_state.regex_flags
                            )
                            
                            # Calculate loss
                            loss = loss_fn(prediction)
                            iteration_losses.append(loss)
                            
                            # Backward pass to compute textual gradients
                            loss.backward()
                            
                        except Exception as e:
                            logger.warning(f"Error in iteration {iteration + 1}, example {idx}: {e}")
                            continue
                    
                    if iteration_losses:
                        # Apply optimization step (updates the system prompt)
                        optimizer.step()
                        
                        # Evaluate on validation set
                        val_scores = []
                        for example in val_examples[:5]:
                            try:
                                user_msg = tg.Variable(
                                    f"Extract the target text from the following input:\n\n{example['raw_text']}",
                                    requires_grad=False,
                                    role_description="user input for regex extraction"
                                )
                                prediction = model(user_msg)
                                score = evaluate_regex_simple(
                                    prediction.value.strip(),
                                    example['raw_text'],
                                    example['ground_truth'],
                                    st.session_state.regex_flags
                                )
                                val_scores.append(score)
                            except Exception as e:
                                val_scores.append(0.0)
                        
                        current_score = np.mean(val_scores) if val_scores else 0.0
                        
                        # Track results
                        history.append({
                            'iteration': iteration + 1,
                            'score': current_score,
                            'prompt': system_prompt.value[:200] + '...' if len(system_prompt.value) > 200 else system_prompt.value
                        })
                        
                        iteration_log.text(f"Iteration {iteration + 1}: Score = {current_score:.2%} (Best: {best_score:.2%})")
                        
                        # Update best if improved
                        if current_score > best_score:
                            best_score = current_score
                            best_prompt = system_prompt.value
                        
                        # Early stopping
                        if best_score >= st.session_state.textgrad_config['early_stopping_threshold']:
                            status_text.text(f"Early stopping - reached threshold {best_score:.2%}")
                            break
                    
                    # Update progress
                    progress_bar.progress(20 + int(70 * (iteration + 1) / num_iterations))
                    
                    # Small delay to avoid rate limits
                    time.sleep(1)
                
                # Final evaluation
                progress_bar.progress(95)
                status_text.text("Final evaluation...")
                
                final_scores = []
                for example in val_examples:
                    try:
                        user_msg = tg.Variable(
                            f"Extract the target text from the following input:\n\n{example['raw_text']}",
                            requires_grad=False,
                            role_description="user input for regex extraction"
                        )
                        prediction = model(user_msg)
                        score = evaluate_regex_simple(
                            prediction.value.strip(),
                            example['raw_text'],
                            example['ground_truth'],
                            st.session_state.regex_flags
                        )
                        final_scores.append(score)
                    except Exception as e:
                        final_scores.append(0.0)
                
                final_avg = np.mean(final_scores) if final_scores else 0.0
                
                progress_bar.progress(100)
                status_text.text("Complete!")
                
                st.session_state.optimized_prompt = best_prompt
                st.session_state.optimization_history.append({
                    'initial_score': initial_avg,
                    'final_score': final_avg,
                    'best_score': best_score,
                    'prompt': best_prompt,
                    'timestamp': pd.Timestamp.now(),
                    'history': history
                })
                
                st.success(f"✅ Optimization Complete! Initial: {initial_avg:.2%} → Best: {best_score:.2%}")
                
        except Exception as e:
            st.error(f"Optimization failed: {e}")
            import traceback
            st.error(traceback.format_exc())
            return
    
    # Display results
    if st.session_state.optimized_prompt:
        st.subheader("📊 Results")
        
        with st.expander("🔍 Optimized Prompt", expanded=True):
            st.code(st.session_state.optimized_prompt, language="text")
        
        # Optimization history
        if st.session_state.optimization_history:
            with st.expander("📈 Optimization History"):
                latest = st.session_state.optimization_history[-1]
                
                col1, col2, col3 = st.columns(3)
                with col1:
                    st.metric("Initial Score", f"{latest['initial_score']:.2%}")
                with col2:
                    st.metric("Final Score", f"{latest['final_score']:.2%}")
                with col3:
                    improvement = latest['best_score'] - latest['initial_score']
                    st.metric("Best Score", f"{latest['best_score']:.2%}", delta=f"{improvement:+.2%}")
                
                if 'history' in latest and latest['history']:
                    history_df = pd.DataFrame(latest['history'])
                    st.line_chart(history_df.set_index('iteration')['score'])


def render_testing_tab():
    """Render the testing tab."""
    st.header("🔍 Test & Validate")
    
    if st.session_state.optimized_prompt is None:
        st.warning("⚠️ Please run optimization first.")
        return
    
    # Single test
    st.subheader("🧪 Single Test")
    
    test_input = st.text_area(
        "Enter test text",
        height=100,
        placeholder="Paste text here to extract regex pattern..."
    )
    
    col1, col2 = st.columns([1, 3])
    with col1:
        test_button = st.button("▶️ Generate & Run", type="primary")
    
    if test_button and test_input:
        if not setup_textgrad():
            return
        
        with st.spinner("Generating regex..."):
            try:
                # Create model with optimized prompt
                system_prompt = tg.Variable(
                    st.session_state.optimized_prompt,
                    requires_grad=False,
                    role_description="optimized system prompt for regex generation"
                )
                
                model = RegexGeneratorModel(
                    system_prompt,
                    st.session_state['target_engine']
                )
                
                user_msg = tg.Variable(
                    f"Extract the target text from the following input:\n\n{test_input}",
                    requires_grad=False,
                    role_description="user input for regex extraction"
                )
                
                result = model(user_msg)
                pattern = result.value.strip()
                
                st.code(f"Generated Regex: {pattern}", language="regex")
                
                # Compile and test
                flags = 0
                for flag in st.session_state.regex_flags:
                    flags |= getattr(re, flag, 0)
                
                compiled = re.compile(pattern, flags)
                matches = compiled.findall(test_input)
                
                if matches:
                    st.success(f"✅ Found {len(matches)} match(es):")
                    for i, match in enumerate(matches, 1):
                        st.markdown(f"**Match {i}:** `{match}`")
                    
                    # Highlight matches in text
                    highlighted = test_input
                    for match in matches:
                        if isinstance(match, str):
                            highlighted = highlighted.replace(
                                match,
                                f"**:green[{match}]**"
                            )
                    st.markdown("**Highlighted text:**")
                    st.markdown(highlighted)
                else:
                    st.warning("No matches found.")
                    
            except re.error as e:
                st.error(f"Invalid regex generated: {e}")
            except Exception as e:
                st.error(f"Error: {e}")
    
    st.divider()
    
    # Batch testing
    st.subheader("📋 Batch Testing")
    
    batch_file = st.file_uploader(
        "Upload test data (CSV with 'text' column)",
        type=["csv"],
        key="batch_test"
    )
    
    if batch_file:
        test_df = pd.read_csv(batch_file)
        
        if 'text' not in test_df.columns:
            st.error("CSV must have 'text' column.")
            return
        
        if st.button("🚀 Run Batch Test"):
            if not setup_textgrad():
                return
            
            results = []
            progress = st.progress(0)
            
            # Create model with optimized prompt
            system_prompt = tg.Variable(
                st.session_state.optimized_prompt,
                requires_grad=False,
                role_description="optimized system prompt for regex generation"
            )
            
            model = RegexGeneratorModel(
                system_prompt,
                st.session_state['target_engine']
            )
            
            for i, row in test_df.iterrows():
                try:
                    user_msg = tg.Variable(
                        f"Extract the target text from the following input:\n\n{row['text']}",
                        requires_grad=False,
                        role_description="user input for regex extraction"
                    )
                    
                    result = model(user_msg)
                    pattern = result.value.strip()
                    
                    flags = 0
                    for flag in st.session_state.regex_flags:
                        flags |= getattr(re, flag, 0)
                    
                    match = re.search(pattern, row['text'], flags)
                    extracted = match.group(0) if match else ""
                    
                    results.append({
                        'text': row['text'][:100] + '...' if len(row['text']) > 100 else row['text'],
                        'pattern': pattern,
                        'extracted': extracted,
                        'success': bool(match)
                    })
                except Exception as e:
                    results.append({
                        'text': row['text'][:100] + '...',
                        'pattern': 'ERROR',
                        'extracted': str(e),
                        'success': False
                    })
                
                progress.progress((i + 1) / len(test_df))
            
            results_df = pd.DataFrame(results)
            
            # Summary metrics
            success_rate = results_df['success'].mean()
            col1, col2 = st.columns(2)
            with col1:
                st.metric("Success Rate", f"{success_rate:.1%}")
            with col2:
                st.metric("Total Tests", len(results_df))
            
            # Results table
            st.dataframe(results_df, use_container_width=True)
            
            # Download results
            csv = results_df.to_csv(index=False)
            st.download_button(
                "📥 Download Results",
                csv,
                "batch_test_results.csv",
                "text/csv"
            )


# --- Main Application ---
def main():
    render_sidebar()
    
    st.title("📝 TextGrad Regex Optimizer")
    st.caption("Automated regex generation with TextGrad text-based optimization")
    
    tab1, tab2, tab3 = st.tabs([
        "📥 Data Ingestion",
        "📝 Optimization",
        "🔍 Testing"
    ])
    
    with tab1:
        render_data_ingestion_tab()
    
    with tab2:
        render_optimization_tab()
    
    with tab3:
        render_testing_tab()
    
    # Footer
    st.divider()
    st.caption(
        "Built with Streamlit and TextGrad | "
        "Configuration is auto-saved in the sidebar"
    )


if __name__ == "__main__":
    main()