import hashlib
from dataclasses import dataclass
from datetime import datetime
from typing import List, Optional

@dataclass
class ProductIdentifier:
    """
    DSCSA-compliant product identifier
    """
    gtin: str  # Global Trade Item Number (NDC in GTIN-14 format)
    serial_number: str
    lot_number: str
    expiration_date: datetime

    def to_serialized_string(self):
        """Convert to DSCSA format"""
        exp_date = self.expiration_date.strftime("%y%m%d")
        return f"(01){self.gtin}(21){self.serial_number}(10){self.lot_number}(17){exp_date}"

    @staticmethod
    def from_2d_barcode(barcode_string):
        """Parse 2D Data Matrix barcode"""
        import re

        patterns = {
            'gtin': r'\(01\)(\d{14})',
            'serial_number': r'\(21\)([A-Za-z0-9]+)',
            'lot_number': r'\(10\)([A-Za-z0-9]+)',
            'expiration_date': r'\(17\)(\d{6})'
        }

        data = {}
        for field, pattern in patterns.items():
            match = re.search(pattern, barcode_string)
            if match:
                value = match.group(1)
                if field == 'expiration_date':
                    data[field] = datetime.strptime(value, "%y%m%d")
                else:
                    data[field] = value

        return ProductIdentifier(**data) if data else None

@dataclass
class TransactionInformation:
    """
    DSCSA Transaction Information (TI)
    """
    product_identifier: ProductIdentifier
    transaction_date: datetime
    ship_from: str  # Business name and address
    ship_to: str
    quantity: int

@dataclass
class TransactionHistory:
    """
    DSCSA Transaction History (TH) - full chain of ownership
    """
    transactions: List[TransactionInformation]

    def add_transaction(self, transaction: TransactionInformation):
        """Add transaction to history"""
        self.transactions.append(transaction)

    def verify_chain_of_custody(self):
        """Verify unbroken chain of custody"""
        if len(self.transactions) < 2:
            return True

        for i in range(len(self.transactions) - 1):
            current = self.transactions[i]
            next_trans = self.transactions[i + 1]

            # Verify ship_to of current matches ship_from of next
            if current.ship_to != next_trans.ship_from:
                return False

        return True

@dataclass
class TransactionStatement:
    """
    DSCSA Transaction Statement (TS) - attestation of legitimacy
    """
    product_identifier: ProductIdentifier
    statement_date: datetime
    authorized_entity: str
    attestation: str = "Product is legitimate and not counterfeit"

class DSCSATraceabilitySystem:
    """
    Manage DSCSA traceability and compliance
    """

    def __init__(self, business_name, dea_number, license_number):
        self.business_name = business_name
        self.dea_number = dea_number
        self.license_number = license_number
        self.inventory = {}
        self.transactions = []

    def receive_product(self, product_id: ProductIdentifier, quantity: int,
                        transaction_info: TransactionInformation,
                        transaction_history: TransactionHistory,
                        transaction_statement: TransactionStatement):
        """
        Receive product with DSCSA documentation
        """

        # Verify transaction history
        if not transaction_history.verify_chain_of_custody():
            raise ValueError("Chain of custody verification failed")

        # Verify product identifier matches
        if product_id.serial_number != transaction_info.product_identifier.serial_number:
            raise ValueError("Product identifier mismatch")

        # Store product in inventory with TI/TH/TS
        inventory_key = f"{product_id.gtin}-{product_id.serial_number}"

        self.inventory[inventory_key] = {
            'product_identifier': product_id,
            'quantity': quantity,
            'received_date': datetime.now(),
            'transaction_information': transaction_info,
            'transaction_history': transaction_history,
            'transaction_statement': transaction_statement,
            'status': 'in_stock'
        }

        return inventory_key

    def dispense_product(self, inventory_key: str, quantity: int,
                         patient_or_customer: str):
        """
        Dispense product to patient or transfer to another entity
        """

        if inventory_key not in self.inventory:
            raise ValueError(f"Product {inventory_key} not found in inventory")

        product_record = self.inventory[inventory_key]

        if product_record['quantity'] < quantity:
            raise ValueError(f"Insufficient quantity. Available: {product_record['quantity']}")

        # Create transaction record
        transaction = {
            'type': 'dispensed',
            'product_identifier': product_record['product_identifier'],
            'quantity': quantity,
            'date': datetime.now(),
            'recipient': patient_or_customer
        }

        self.transactions.append(transaction)

        # Update inventory
        product_record['quantity'] -= quantity

        if product_record['quantity'] == 0:
            product_record['status'] = 'dispensed'

        return transaction

    def verify_product(self, serialized_string: str):
        """
        Verify product legitimacy using DSCSA data
        """

        product_id = ProductIdentifier.from_2d_barcode(serialized_string)

        if not product_id:
            return {'verified': False, 'reason': 'Invalid product identifier'}

        inventory_key = f"{product_id.gtin}-{product_id.serial_number}"

        if inventory_key in self.inventory:
            product = self.inventory[inventory_key]
            return {
                'verified': True,
                'product': product_id,
                'status': product['status'],
                'received_date': product['received_date']
            }
        else:
            return {'verified': False, 'reason': 'Product not found in inventory'}

    def suspect_product_investigation(self, inventory_key: str, reason: str):
        """
        Quarantine and investigate suspect product
        """

        if inventory_key not in self.inventory:
            raise ValueError(f"Product {inventory_key} not found")

        product = self.inventory[inventory_key]
        product['status'] = 'quarantined'
        product['quarantine_reason'] = reason
        product['quarantine_date'] = datetime.now()

        # Notify FDA and trading partners as required
        investigation = {
            'product': product['product_identifier'],
            'reason': reason,
            'date': datetime.now(),
            'actions_taken': 'Product quarantined, investigation initiated'
        }

        return investigation

---

import pandas as pd
from datetime import datetime
from enum import Enum

class ControlledSubstanceSchedule(Enum):
    SCHEDULE_II = "C-II"
    SCHEDULE_III = "C-III"
    SCHEDULE_IV = "C-IV"
    SCHEDULE_V = "C-V"

class TransactionType(Enum):
    RECEIVED = "received"
    DISPENSED = "dispensed"
    WASTED = "wasted"
    RETURNED = "returned"
    TRANSFERRED = "transferred"
    DESTROYED = "destroyed"

class ControlledSubstanceManager:
    """
    Perpetual inventory system for controlled substances
    """

    def __init__(self, pharmacy_name, dea_number):
        self.pharmacy_name = pharmacy_name
        self.dea_number = dea_number
        self.inventory = {}
        self.transactions = []

    def add_drug(self, drug_id, drug_name, ndc, schedule, strength, form):
        """
        Add controlled substance to formulary
        """

        self.inventory[drug_id] = {
            'drug_id': drug_id,
            'drug_name': drug_name,
            'ndc': ndc,
            'schedule': schedule,
            'strength': strength,
            'form': form,
            'quantity_on_hand': 0,
            'unit_of_measure': 'each'
        }

    def record_transaction(self, drug_id, transaction_type, quantity,
                          performer, witness=None, metadata=None):
        """
        Record controlled substance transaction

        Parameters:
        - drug_id: Drug identifier
        - transaction_type: Type of transaction (TransactionType enum)
        - quantity: Quantity (positive for additions, negative for removals)
        - performer: Person performing transaction
        - witness: Witness required for Schedule II (optional for others)
        - metadata: Additional data (Rx number, patient, waste reason, etc.)
        """

        if drug_id not in self.inventory:
            raise ValueError(f"Drug {drug_id} not in inventory")

        drug = self.inventory[drug_id]

        # Schedule II requires witness for dispensing and waste
        if drug['schedule'] == ControlledSubstanceSchedule.SCHEDULE_II:
            if transaction_type in [TransactionType.DISPENSED, TransactionType.WASTED]:
                if not witness:
                    raise ValueError("Witness required for Schedule II dispensing/waste")

        # Create transaction record
        transaction = {
            'transaction_id': len(self.transactions) + 1,
            'timestamp': datetime.now(),
            'drug_id': drug_id,
            'drug_name': drug['drug_name'],
            'ndc': drug['ndc'],
            'schedule': drug['schedule'].value,
            'transaction_type': transaction_type.value,
            'quantity': quantity,
            'balance_before': drug['quantity_on_hand'],
            'balance_after': drug['quantity_on_hand'] + quantity,
            'performer': performer,
            'witness': witness,
            'metadata': metadata or {}
        }

        # Update inventory
        drug['quantity_on_hand'] += quantity

        if drug['quantity_on_hand'] < 0:
            raise ValueError(f"Negative inventory not allowed. Current: {drug['quantity_on_hand']}")

        # Store transaction
        self.transactions.append(transaction)

        return transaction

    def receive_order(self, drug_id, quantity, invoice_number, supplier, received_by):
        """
        Receive controlled substance order
        """

        return self.record_transaction(
            drug_id=drug_id,
            transaction_type=TransactionType.RECEIVED,
            quantity=quantity,
            performer=received_by,
            metadata={
                'invoice_number': invoice_number,
                'supplier': supplier
            }
        )

    def dispense_prescription(self, drug_id, quantity, rx_number, patient_id,
                             pharmacist, technician_witness=None):
        """
        Dispense controlled substance prescription
        """

        return self.record_transaction(
            drug_id=drug_id,
            transaction_type=TransactionType.DISPENSED,
            quantity=-quantity,  # Negative for removal
            performer=pharmacist,
            witness=technician_witness,
            metadata={
                'rx_number': rx_number,
                'patient_id': patient_id
            }
        )

    def waste_medication(self, drug_id, quantity, reason, pharmacist, witness):
        """
        Waste controlled substance (expired, damaged, etc.)
        """

        return self.record_transaction(
            drug_id=drug_id,
            transaction_type=TransactionType.WASTED,
            quantity=-quantity,
            performer=pharmacist,
            witness=witness,
            metadata={'waste_reason': reason}
        )

    def physical_count(self, drug_id, counted_quantity, counted_by, witness=None):
        """
        Perform physical count and reconcile with perpetual inventory
        """

        if drug_id not in self.inventory:
            raise ValueError(f"Drug {drug_id} not in inventory")

        drug = self.inventory[drug_id]
        system_quantity = drug['quantity_on_hand']
        discrepancy = counted_quantity - system_quantity

        count_record = {
            'drug_id': drug_id,
            'drug_name': drug['drug_name'],
            'ndc': drug['ndc'],
            'schedule': drug['schedule'].value,
            'count_date': datetime.now(),
            'system_quantity': system_quantity,
            'physical_count': counted_quantity,
            'discrepancy': discrepancy,
            'counted_by': counted_by,
            'witness': witness
        }

        return count_record

    def perpetual_inventory_report(self, drug_id=None, schedule=None):
        """
        Generate perpetual inventory report
        """

        transactions_df = pd.DataFrame(self.transactions)

        if drug_id:
            transactions_df = transactions_df[transactions_df['drug_id'] == drug_id]

        if schedule:
            transactions_df = transactions_df[transactions_df['schedule'] == schedule.value]

        return transactions_df

    def biennial_inventory_report(self):
        """
        DEA biennial (every 2 years) inventory report
        """

        inventory_list = []

        for drug_id, drug in self.inventory.items():
            inventory_list.append({
                'drug_name': drug['drug_name'],
                'ndc': drug['ndc'],
                'schedule': drug['schedule'].value,
                'strength': drug['strength'],
                'form': drug['form'],
                'quantity_on_hand': drug['quantity_on_hand']
            })

        inventory_df = pd.DataFrame(inventory_list)
        inventory_df = inventory_df.sort_values(['schedule', 'drug_name'])

        report = {
            'pharmacy_name': self.pharmacy_name,
            'dea_number': self.dea_number,
            'report_date': datetime.now(),
            'inventory': inventory_df
        }

        return report

---

class Patient340BEligibility:
    """
    Determine 340B patient eligibility
    """

    def __init__(self, covered_entity_id, entity_type):
        self.covered_entity_id = covered_entity_id
        self.entity_type = entity_type  # DSH, PED, CAH, FQHC, etc.

    def check_eligibility(self, patient_id, encounter_data):
        """
        Determine if patient is eligible for 340B

        Patient must meet all criteria:
        1. Established relationship with covered entity
        2. Received healthcare service from covered entity
        3. Covered entity has responsibility for care
        4. Drug prescribed by provider of covered entity
        5. Drug dispensed by eligible pharmacy
        """

        criteria = {
            'established_patient': self._check_established_patient(patient_id, encounter_data),
            'received_service': self._check_service_received(encounter_data),
            'provider_responsibility': self._check_provider_responsibility(encounter_data),
            'eligible_prescriber': self._check_eligible_prescriber(encounter_data),
            'eligible_pharmacy': self._check_eligible_pharmacy(encounter_data)
        }

        # All criteria must be met
        eligible = all(criteria.values())

        return {
            'eligible': eligible,
            'criteria_results': criteria,
            'reason': self._eligibility_reason(criteria) if not eligible else 'Meets all criteria'
        }

    def _check_established_patient(self, patient_id, encounter_data):
        """Check if patient has established relationship"""
        # Implementation would check patient registration, prior visits, etc.
        return encounter_data.get('established_patient', False)

    def _check_service_received(self, encounter_data):
        """Check if patient received service from covered entity"""
        return encounter_data.get('service_location') == self.covered_entity_id

    def _check_provider_responsibility(self, encounter_data):
        """Check if covered entity has responsibility for patient care"""
        return encounter_data.get('responsible_entity') == self.covered_entity_id

    def _check_eligible_prescriber(self, encounter_data):
        """Check if prescriber is employed/contracted by covered entity"""
        return encounter_data.get('prescriber_entity') == self.covered_entity_id

    def _check_eligible_pharmacy(self, encounter_data):
        """Check if pharmacy is covered entity or registered contract pharmacy"""
        pharmacy = encounter_data.get('dispensing_pharmacy')
        return pharmacy in [self.covered_entity_id] or \
               pharmacy in self._get_contract_pharmacies()

    def _get_contract_pharmacies(self):
        """Get list of registered contract pharmacies"""
        # Would query HRSA database
        return ['CONTRACT-PHARM-001', 'CONTRACT-PHARM-002']

    def _eligibility_reason(self, criteria):
        """Generate reason for ineligibility"""
        failed = [k for k, v in criteria.items() if not v]
        return f"Failed criteria: {', '.join(failed)}"

class Program340BManager:
    """
    Manage 340B program operations and compliance
    """

    def __init__(self, covered_entity_id):
        self.covered_entity_id = covered_entity_id
        self.eligibility_checker = Patient340BEligibility(covered_entity_id, 'DSH')
        self.purchases = []
        self.dispenses = []

    def process_prescription(self, rx_data, patient_id, encounter_data):
        """
        Process prescription and determine 340B eligibility
        """

        # Check patient eligibility
        eligibility = self.eligibility_checker.check_eligibility(patient_id, encounter_data)

        # Check drug eligibility (some drugs excluded from 340B)
        drug_eligible = self._check_drug_eligibility(rx_data['ndc'])

        # Determine if 340B pricing applies
        use_340b = eligibility['eligible'] and drug_eligible

        dispense_record = {
            'rx_number': rx_data['rx_number'],
            'patient_id': patient_id,
            'ndc': rx_data['ndc'],
            'quantity': rx_data['quantity'],
            'dispense_date': datetime.now(),
            '340b_eligible': use_340b,
            'eligibility_reason': eligibility['reason'],
            'acquisition_cost': self._get_acquisition_cost(rx_data['ndc'], use_340b)
        }

        self.dispenses.append(dispense_record)

        return dispense_record

    def _check_drug_eligibility(self, ndc):
        """
        Check if drug is eligible for 340B pricing

        Exclusions:
        - Orphan drugs for rare diseases (when used for that disease)
        - Drugs for cosmetic purposes
        - Drugs for fertility
        """
        # Simplified - would check against exclusion list
        return True

    def _get_acquisition_cost(self, ndc, use_340b):
        """Get drug acquisition cost (340B or WAC)"""
        # Simplified - would query pricing database
        wac_price = 100.00
        price_340b = wac_price * 0.60  # Typical 40% discount

        return price_340b if use_340b else wac_price

    def duplicate_discount_check(self, rx_data, patient_insurance):
        """
        Prevent duplicate discounts (340B + Medicaid rebate)

        Covered entities cannot receive 340B discount AND Medicaid rebate
        """

        is_medicaid = patient_insurance.get('payer_type') == 'Medicaid'
        is_340b = rx_data.get('340b_eligible', False)

        if is_medicaid and is_340b:
            # Options:
            # 1. Carve-out: Don't bill Medicaid, use 340B
            # 2. Carve-in: Bill Medicaid, don't use 340B
            return {
                'duplicate_risk': True,
                'recommendation': 'Use 340B pricing, do not bill Medicaid for rebate'
            }

        return {'duplicate_risk': False}

    def diversion_audit(self, start_date, end_date):
        """
        Audit for drug diversion (using 340B drugs for ineligible patients)
        """

        dispenses_df = pd.DataFrame(self.dispenses)

        # Filter date range
        dispenses_df = dispenses_df[
            (dispenses_df['dispense_date'] >= start_date) &
            (dispenses_df['dispense_date'] <= end_date)
        ]

        # Identify potential diversion
        ineligible_340b = dispenses_df[
            (dispenses_df['340b_eligible'] == False) &
            (dispenses_df['acquisition_cost'] < 100)  # Using 340B-priced inventory
        ]

        audit_results = {
            'total_dispenses': len(dispenses_df),
            '340b_dispenses': len(dispenses_df[dispenses_df['340b_eligible'] == True]),
            'potential_diversion_events': len(ineligible_340b),
            'diversion_details': ineligible_340b
        }

        return audit_results