import gradio as gr
import pandas as pd
import tempfile
import os

def process_excel(file):
    if file is None:
        return pd.DataFrame(columns=['Student', 'Email', 'Answers/Question', 'Score', 'Comment']), None

    try:
        df = pd.read_excel(file)
    except Exception as e:
        return pd.DataFrame(columns=['Student', 'Email', 'Answers/Question', 'Score', 'Comment']), None

    # Fill forward key metadata columns if they exist
    for col in ['Student', 'Email', 'Status', 'Survey']:
        if col in df.columns:
            df[col] = df[col].ffill()

    # Clean column names (strip spaces)
    df.columns = [col.strip() for col in df.columns]

    # Map for flexible column names (remove spaces, '/', '_', lowercase)
    col_map = {col.lower().replace(' ', '').replace('/', '').replace('_', ''): col for col in df.columns}

    student_col = col_map.get('student', None)
    email_col = col_map.get('email', None)
    question_col = None
    for candidate in ['answersquestion', 'question']:
        if candidate in col_map:
            question_col = col_map[candidate]
            break
    answers_col = col_map.get('answers', None)

    # If any required column missing, return empty DataFrame
    if not all([student_col, email_col, question_col, answers_col]):
        return pd.DataFrame(columns=['Student', 'Email', 'Answers/Question', 'Score', 'Comment']), None

    # Extract Score and Comment from 'Answers' column (e.g. "4: Some comment")
    df[['Score', 'Comment']] = df[answers_col].astype(str).str.extract(r'^\s*(\d+)\s*[:\-]\s*(.*)$')

    # Handle rows with just a score and no comment (e.g. "4")
    score_only_mask = df[answers_col].astype(str).str.match(r'^\s*\d+\s*$')
    df.loc[score_only_mask, 'Score'] = df.loc[score_only_mask, answers_col].str.strip()
    df.loc[score_only_mask, 'Comment'] = ""

    # Build output DataFrame with required columns
    output_df = pd.DataFrame()
    output_df['Student'] = df[student_col]
    output_df['Email'] = df[email_col]
    output_df['Answers/Question'] = df[question_col]
    output_df['Score'] = df['Score']
    output_df['Comment'] = df['Comment']

    # Drop rows missing any of these essential fields
    output_df = output_df.dropna(subset=['Student', 'Email', 'Answers/Question', 'Score'])
    output_df = output_df.reset_index(drop=True)

    # Save the cleaned data to a temporary Excel file for download
    temp_dir = tempfile.gettempdir()
    temp_path = os.path.join(temp_dir, "survey_answers_clean.xlsx")
    output_df.to_excel(temp_path, index=False)

    # Return preview (first 100 rows) and file path for download
    return output_df.head(100), temp_path


title = "Survey Data Transformer"
description = """
Upload your survey Excel report.<br>
The output will always have these columns:<br><b>Student, Email, Answers/Question, Score, Comment</b>.<br>
Check the preview and download the cleaned Excel file.
"""

gr.Interface(
    fn=process_excel,
    inputs=gr.File(label="Upload Excel File"),
    outputs=[
        gr.Dataframe(label="Preview (first 100 rows)"),
        gr.File(label="Download Cleaned Excel")
    ],
    title=title,
    description=description,
    allow_flagging="never",
).launch()