import spacy
import re
import subprocess

try:
    nlp = spacy.load("en_core_web_sm")
except OSError:
    subprocess.run(["python", "-m", "spacy", "download", "en_core_web_sm"], check=True)
    nlp = spacy.load("en_core_web_sm")


FULL_NAME_PATTERN = r'My name is ([A-Za-z\s\.\-]+)[\.,]|Name\s*:\s*([A-Za-z\s\.\-]+)[\.,]'
EMAIL_PATTERN = r'You can reach me at ([A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,})|Email\s*:\s*([A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,})'
PHONE_PATTERN = r'My [Cc]ontact number is\s*([+\d\s\-\(\)\.]+)|Phone\s*:\s*([+\d\s\-\(\)\.]+)|(\+?\d{1,4}?[-.\s]?\(?\d{1,3}?\)?[-.\s]?\d{1,4}[-.\s]?\d{1,4}[-.\s]?\d{1,9})'
DOB_PATTERN = r'[Dd]ate of [Bb]irth\s*:?\s*(\d{1,2}[-/\.]\d{1,2}[-/\.]\d{2,4}|\d{2,4}[-/\.]\d{1,2}[-/\.]\d{1,2})'
AADHAR_PATTERN = r'[Aa]adhar(?:\s*[Cc]ard)?\s*(?:[Nn]umber)?\s*:?\s*(\d{4}\s*\d{4}\s*\d{4}|\d{12})'
CREDIT_DEBIT_PATTERN = r'[Cc](?:redit|ard)\s*(?:[Nn]umber)?\s*:?\s*(\d{4}[-\s]?\d{4}[-\s]?\d{4}[-\s]?\d{4}|\d{16})'
CVV_PATTERN = r'[Cc][Vv][Vv]\s*(?:[Nn]umber)?\s*:?\s*(\d{3,4})'
EXPIRY_PATTERN = r'[Ee]xpir(?:y|ation)\s*[Dd]ate\s*:?\s*(\d{1,2}[-/\.]\d{2,4}|\d{2}[-/\.]\d{2})'

def preprocess_text(text):
    """Clean and normalize text before processing."""
    text = re.sub(r'\n{2,}', '\n', text)
    text = text.replace('\n', ' ')
    text = re.sub(r'\s+', ' ', text)
    text = text.replace('\xa0', ' ')
    text = text.replace('"', '')

    return text.strip()

def mask_pii(email_text):
    """Mask PII in emails using regex patterns with the required entity fields."""
    if not email_text or len(email_text.strip()) == 0:
        return ""

    masked_text = preprocess_text(email_text)
    pii_entities = {}
    name_matches = re.finditer(FULL_NAME_PATTERN, masked_text)
    for match in name_matches:
        full_match = match.group(0)
        name = next((g for g in match.groups() if g), "")
        if name:
            pii_entities["full_name"] = name
            if "My name is" in full_match:
                masked_text = masked_text.replace(full_match, "My name is <full_name>.")
            elif "Name:" in full_match:
                masked_text = masked_text.replace(full_match, "Name: <full_name>.")
            else:
                masked_text = masked_text.replace(name, "<full_name>")

    email_matches = re.finditer(EMAIL_PATTERN, masked_text)
    for match in email_matches:
        full_match = match.group(0)
        email = next((g for g in match.groups() if g), "")
        if email:
            pii_entities["email"] = email
            if "You can reach me at" in full_match:
                masked_text = masked_text.replace(full_match, "You can reach me at <email>")
            elif "Email" in full_match:
                masked_text = masked_text.replace(full_match, "Email: <email>")
            else:
                masked_text = masked_text.replace(email, "<email>")

    phone_matches = re.finditer(PHONE_PATTERN, masked_text)
    for match in phone_matches:
        full_match = match.group(0)
        phone = next((g for g in match.groups() if g), "")
        if phone:
            pii_entities["phone_number"] = phone
            if "My contact number is" in full_match or "My Contact number is" in full_match:
                masked_text = masked_text.replace(full_match, "My contact number is <phone_number>")
            elif "Phone" in full_match:
                masked_text = masked_text.replace(full_match, "Phone: <phone_number>")
            else:
                masked_text = masked_text.replace(phone, "<phone_number>")

    dob_matches = re.finditer(DOB_PATTERN, masked_text)
    for match in dob_matches:
        full_match = match.group(0)
        dob = match.group(1)
        if dob:
            pii_entities["dob"] = dob
            masked_text = masked_text.replace(full_match, "Date of Birth: <dob>")

    aadhar_matches = re.finditer(AADHAR_PATTERN, masked_text)
    for match in aadhar_matches:
        full_match = match.group(0)
        aadhar = match.group(1)
        if aadhar:
            pii_entities["aadhar_num"] = aadhar
            masked_text = masked_text.replace(full_match, "Aadhar Number: <aadhar_num>")

    card_matches = re.finditer(CREDIT_DEBIT_PATTERN, masked_text)
    for match in card_matches:
        full_match = match.group(0)
        card = match.group(1)
        if card:
            pii_entities["credit_debit_no"] = card
            masked_text = masked_text.replace(full_match, "Card Number: <credit_debit_no>")

    cvv_matches = re.finditer(CVV_PATTERN, masked_text)
    for match in cvv_matches:
        full_match = match.group(0)
        cvv = match.group(1)
        if cvv:
            pii_entities["cvv_no"] = cvv
            masked_text = masked_text.replace(full_match, "CVV: <cvv_no>")

    expiry_matches = re.finditer(EXPIRY_PATTERN, masked_text)
    for match in expiry_matches:
        full_match = match.group(0)
        expiry = match.group(1)
        if expiry:
            pii_entities["expiry_no"] = expiry
            masked_text = masked_text.replace(full_match, "Expiry Date: <expiry_no>")

    doc = nlp(masked_text)
    for ent in doc.ents:
        if ent.label_ == "PERSON" and "full_name" not in pii_entities:
            masked_text = masked_text.replace(ent.text, "<full_name>")

    return masked_text