import PyPDF2
import re

## re Patterns
schedule_pattern = r"(?<=NOTES)(.*?)(?=NOTES|$)" # Split Schedule Cards
train_start_pattern = r"\b\d[A-Z]\d{2}\s+\d{5}\s+\d{2}\.\d{2}(?:\s+\d{2}\.\d{2})?\s+[A-Za-z &]+" # Defines start of train section
train_first_line_pattern = r"(?P<headcode>\d[A-Z]\d{2})\s+(?P<gsmr_code>\d{5})\s+(?P<time0>\d{2}\.\d{2})(?:\s+(?P<time1>\d{2}\.\d{2}))?\s+(?P<location>[A-Za-z0-9& ]+)" # Extracts Train Data
train_pis_line_pattern = r"\(PIS Code\s*:\s*(?P<pis_code>\d+)\s*\)" # Extracts PIS Code

# Extract Schedule Cards to list of strings

def extract_pdf_text(file_path):
    with open(file_path, 'rb') as file:
        pdf_reader = PyPDF2.PdfReader(file)
        
        page_texts = []
        for page in pdf_reader.pages:
            text = page.extract_text()
            if text:
                page_texts.append(text)

        full_text = " ".join(page_texts)
        return full_text

# Does everything - should be split in to functional functions
def parse_pdf_file(filename):
    pdf_text = extract_pdf_text(filename)
    schedule_cards = re.findall(schedule_pattern, pdf_text, re.DOTALL)
    print(f"{len(schedule_cards)} Schedule Cards parsed")

    # Split into individual trains
    parsed_schedule_cards = []

    for schedule_card in schedule_cards:
        train_sections = re.split(f"(?={train_start_pattern})", schedule_cards[0])
        train_sections = [section.strip() for section in train_sections if section.strip()]

        parsed_schedule_cards.append(train_sections)

    # Process data from each individual train


    train_data = []

    for parsed_schedule_card in parsed_schedule_cards:
        for train in parsed_schedule_card:
            first_line_match = re.match(train_first_line_pattern, train)
            if first_line_match:
                train_entry = first_line_match.groupdict()
                pis_code_match = re.search(train_pis_line_pattern, train)
                train_entry["pis_code"] = pis_code_match.group("pis_code") if pis_code_match else None

                train_data.append(train_entry)

    return train_data