import pandas as pd
import openpyxl  # ensure XLSX engine is available
import gradio as gr
import uuid
import os

# 7-Day Schedule Converter with explicit iteration and header fill and download support

def convert_schedule(file_path, direction):
    try:
        # 1. Load raw header rows to determine day labels
        raw = pd.read_excel(file_path, header=None)
        header1 = raw.iloc[0, 1:].astype(object)
        header2 = raw.iloc[1, 1:].astype(object)

        # Decide which header row to use: prefer second if fully populated
        if header2.notna().all() and not header2.str.startswith('Unnamed').any():
            days = header2.tolist()
            data_start = 2
        else:
            # Forward-fill merged first-row headers
            days = []
            last = None
            for val in header1:
                if pd.isna(val) or str(val).startswith('Unnamed'):
                    days.append(last)
                else:
                    last = str(val)
                    days.append(last)
            data_start = 1

        # 2. Load actual data using resolved day columns
        df = pd.read_excel(
            file_path,
            header=data_start,
            index_col=0,
            usecols=[0] + list(range(1, len(days) + 1))
        )
        df.columns = [str(day) for day in days]

        # 3. Retain original day column order
        day_cols = list(df.columns)

        # 4. Build assignment mapping via explicit iteration
        assignments = {}
        if direction == 'A to B':
            # Models in rows → Texters as rows
            for model in df.index.astype(str):
                for day in day_cols:
                    cell = df.at[model, day]
                    # Handle NaN values properly
                    if pd.isna(cell):
                        continue
                    for texter in str(cell).split(','):
                        texter = texter.strip()
                        if not texter or texter.lower() in ['nan', 'none', '']:
                            continue
                        assignments.setdefault(texter, {d: [] for d in day_cols})
                        assignments[texter][day].append(model)
            
            if not assignments:  # Handle empty assignments
                result = pd.DataFrame(columns=day_cols)
                first_col_name = 'Texter'
            else:
                index = sorted(assignments.keys())
                result = pd.DataFrame(index=index, columns=day_cols)
                first_col_name = 'Texter'
                for texter, days_map in assignments.items():
                    for day in day_cols:
                        models = days_map.get(day, [])
                        result.at[texter, day] = ', '.join(models) if models else 'OFF'
        else:
            # Texters in rows → Models as rows
            for texter in df.index.astype(str):
                for day in day_cols:
                    cell = df.at[texter, day]
                    # Handle NaN values properly
                    if pd.isna(cell):
                        continue
                    for model in str(cell).split(','):
                        model = model.strip()
                        if not model or model.lower() in ['nan', 'none', '']:
                            continue
                        assignments.setdefault(model, {d: [] for d in day_cols})
                        assignments[model][day].append(texter)
            
            if not assignments:  # Handle empty assignments
                result = pd.DataFrame(columns=day_cols)
                first_col_name = 'Model'
            else:
                index = sorted(assignments.keys())
                result = pd.DataFrame(index=index, columns=day_cols)
                first_col_name = 'Model'
                for model, days_map in assignments.items():
                    for day in day_cols:
                        texters = days_map.get(day, [])
                        result.at[model, day] = ', '.join(texters) if texters else 'OFF'

        # 5. Cleanup axis names
        result.index.name = None
        result.columns.name = None

        # For display, include index as a column
        display_df = result.reset_index().rename(columns={'index': first_col_name})

        # 6. Save to Excel for download with better error handling
        output_filename = f"converted_{uuid.uuid4().hex}.xlsx"
        
        # Clean the DataFrame before saving
        result_clean = result.copy()
        
        # Replace any problematic values
        result_clean = result_clean.fillna('OFF')  # Fill NaN with 'OFF'
        
        # Ensure all values are strings to avoid Excel compatibility issues
        for col in result_clean.columns:
            result_clean[col] = result_clean[col].astype(str)
        
        # Save with additional parameters for better compatibility
        with pd.ExcelWriter(output_filename, engine='openpyxl', mode='w') as writer:
            result_clean.to_excel(writer, sheet_name='Schedule', index=True, header=True)

        # Return both DataFrame and download path
        return display_df, output_filename

    except Exception as e:
        # Return error information
        error_df = pd.DataFrame({'Error': [f"Error processing file: {str(e)}"]})
        return error_df, None

# Build Gradio interface and launch immediately for Hugging Face Spaces
iface = gr.Interface(
    fn=convert_schedule,
    inputs=[
        gr.File(label='Upload Weekly Schedule (.xlsx)', file_count='single', type='filepath'),
        gr.Radio(['A to B', 'B to A'], label='Convert Direction', value='A to B')  # Added default value
    ],
    outputs=[
        gr.Dataframe(label='Converted Schedule'),
        gr.File(label='Download Converted Excel')
    ],
    title='7-Day Schedule Converter',
    description=(
        'Upload a 7-column weekly schedule (Models vs Days) with merged or single headers, '
        'then flip between Models→Texters or Texters→Models. Download the result as .xlsx.'
    ),
    flagging_mode='never'
)

# Launch on 0.0.0.0:7860 for Spaces
if __name__ == "__main__":
    iface.launch(server_name='0.0.0.0', server_port=7860)