core/processing.py

import re

def parse_transcript_into_qa(transcript_string: str):
    """
    Parses a transcript string with speaker labels into a structured Q&A format.
    It assumes the first speaker is the interviewer and groups consecutive lines
    from the same speaker.

    Args:
        transcript_string: A multi-line string from the STT service.
        e.g., "Speaker 0: Hello\nSpeaker 1: Hi there\nSpeaker 0: How are you?"

    Returns:
        A list of dictionaries, where each dictionary represents a Q&A pair.
        e.g., [{"question": "...", "answer": "..."}]
    """
    if not transcript_string or not isinstance(transcript_string, str):
        return []

    lines = transcript_string.strip().split('\n')
    if not lines:
        return []

    # Define a flexible regex to find speaker labels
    speaker_regex = re.compile(r'^(Speaker \d+|Interviewer|Candidate):', re.IGNORECASE)

    # Find the first speaker to identify the interviewer
    first_speaker_match = speaker_regex.search(lines[0])
    if not first_speaker_match:
        # If the format is unexpected, we can't proceed reliably.
        return []
    interviewer_id = first_speaker_match.group(1).strip(':')

    qa_pairs = []
    current_question = ""
    current_answer = ""
    last_speaker = None

    for line in lines:
        line = line.strip()
        if not line:
            continue

        speaker_match = speaker_regex.search(line)
        text_content = re.sub(speaker_regex, '', line, 1).strip()
        if not speaker_match:
            # If a line doesn't have a speaker, append it to the last utterance
            if last_speaker and interviewer_id.lower() in last_speaker.lower():
                current_question += " " + line
            elif last_speaker:
                current_answer += " " + line
            continue

        current_speaker = speaker_match.group(1).strip(':')
        text = text_content

        # Check if the current speaker is the interviewer, case-insensitively
        if interviewer_id.lower() in current_speaker.lower():
            # New question starts. If we have a completed Q&A, save it.
            if current_question and current_answer:
                qa_pairs.append({
                    "qa_id": len(qa_pairs) + 1,
                    "question": current_question.strip(), 
                    "answer": current_answer.strip()
                })
                current_answer = ""
                current_question = text
            else:
                # This handles consecutive questions or the very first question
                current_question = (current_question + " " + text).strip()
        else:
            # This is an answer from the candidate
            current_answer = (current_answer + " " + text).strip()
        
        last_speaker = current_speaker

    # Add the last Q&A pair to the list
    if current_question and current_answer:
        qa_pairs.append({
            "qa_id": len(qa_pairs) + 1,
            "question": current_question.strip(), 
            "answer": current_answer.strip()
        })

    return qa_pairs


def test_parse_transcript_into_qa():
    """Test suite for the parse_transcript_into_qa function."""
    print("Running tests for parse_transcript_into_qa...")

    # Test Case 1: Basic 'Speaker' format
    test_1_input = """
Speaker 0: What is your greatest strength?
Speaker 1: My greatest strength is my persistence.
"""
    test_1_expected = [{'qa_id': 1, 'question': 'What is your greatest strength?', 'answer': 'My greatest strength is my persistence.'}]
    assert parse_transcript_into_qa(test_1_input) == test_1_expected, "Test Case 1 Failed"
    print("Test Case 1 Passed")

    # Test Case 2: 'Interviewer/Candidate' format, case-insensitive
    test_2_input = """
interviewer: Tell me about a challenge you faced.
Candidate: I once had to meet a very tight deadline.
"""
    test_2_expected = [{'qa_id': 1, 'question': 'Tell me about a challenge you faced.', 'answer': 'I once had to meet a very tight deadline.'}]
    assert parse_transcript_into_qa(test_2_input) == test_2_expected, "Test Case 2 Failed"
    print("Test Case 2 Passed")

    # Test Case 3: Multi-line answer and question
    test_3_input = """
Speaker 0: Can you describe your experience with Python?
It is a key requirement for this role.
Speaker 1: Certainly. I have over five years of experience.
I have used it for web development and data analysis.
"""
    test_3_expected = [{'qa_id': 1, 'question': 'Can you describe your experience with Python? It is a key requirement for this role.', 'answer': 'Certainly. I have over five years of experience. I have used it for web development and data analysis.'}]
    assert parse_transcript_into_qa(test_3_input) == test_3_expected, "Test Case 3 Failed"
    print("Test Case 3 Passed")

    # Test Case 4: Multiple Q&A pairs
    test_4_input = """
Interviewer: First question?
Candidate: First answer.
Interviewer: Second question?
Candidate: Second answer.
"""
    test_4_expected = [
        {'qa_id': 1, 'question': 'First question?', 'answer': 'First answer.'},
        {'qa_id': 2, 'question': 'Second question?', 'answer': 'Second answer.'}
    ]
    assert parse_transcript_into_qa(test_4_input) == test_4_expected, "Test Case 4 Failed"
    print("Test Case 4 Passed")

    # Test Case 5: Edge case - Empty and whitespace strings
    assert parse_transcript_into_qa("") == [], "Test Case 5.1 Failed"
    assert parse_transcript_into_qa("   \n   ") == [], "Test Case 5.2 Failed"
    print("Test Case 5 Passed")

    # Test Case 6: Edge case - No speaker labels
    test_6_input = "This is just a block of text without any speakers."
    assert parse_transcript_into_qa(test_6_input) == [], "Test Case 6 Failed"
    print("Test Case 6 Passed")

    # Test Case 7: Transcript starts with Candidate
    test_7_input = """
Candidate: I have a question first.
Interviewer: Please go ahead.
"""
    # Expects the first speaker to be the interviewer, so this will be parsed with C as Q and I as A
    test_7_expected = [{'qa_id': 1, 'question': 'I have a question first.', 'answer': 'Please go ahead.'}]
    assert parse_transcript_into_qa(test_7_input) == test_7_expected, "Test Case 7 Failed"
    print("Test Case 7 Passed")

    print("\nAll tests passed successfully!")

if __name__ == '__main__':
    # First, run the standard test suite
    # test_parse_transcript_into_qa()

    # Then, test with the real example file
    import json
    print("\n" + "-"*50)
    print("--- Testing with example_interview_transcipt.txt ---")
    print("-"*50)

    # The script is in core/, the example is in examples/
    # So we need to go up one level and then into examples/
    file_path = 'e:/projects/intelcruit/backend/examples/example_interview_transcipt.txt'
    
    try:
        with open(file_path, 'r', encoding='utf-8') as f:
            transcript_content = f.read()
        
        qa_pairs = parse_transcript_into_qa(transcript_content)
        
        print(f"\nFound {len(qa_pairs)} Q&A pairs.")
        output_file_path = 'test_output.json'
        print(f"Writing output to {output_file_path}...")
        with open(output_file_path, 'w', encoding='utf-8') as f_out:
            json.dump(qa_pairs, f_out, indent=2, ensure_ascii=False)
        print(f"Successfully wrote results to {output_file_path}")
        
    except FileNotFoundError:
        print(f"\nError: Test file not found at {file_path}")
    except Exception as e:
        print(f"\nAn error occurred: {e}")