import cherrypy
from sqlalchemy.orm import sessionmaker
from datetime import datetime
from accounting.models import Account, BankAccount, BankTransaction, JournalEntry, JournalEntryLine, ReconciliationReport, \
    ReconciliationMatch
import simplejson as json


class AccountingAPI:
    def __init__(self, db_engine):
        self.db_engine = db_engine
        Session = sessionmaker(bind=db_engine)
        self.session = Session()

    @cherrypy.expose
    @cherrypy.tools.json_out()
    def index(self):
        return {"status": "success", "message": "Accounting API is running"}

    # Bank Accounts Endpoints
    @cherrypy.expose
    @cherrypy.tools.json_out()
    def bank_accounts(self):
        if cherrypy.request.method != 'GET':
            raise cherrypy.HTTPError(405)

        accounts = self.session.query(BankAccount).all()
        return [{
            'id': a.id,
            'name': a.name,
            'bank_name': a.bank_name,
            'account_number': a.account_number,
            'currency': a.currency
        } for a in accounts]

    @cherrypy.expose
    @cherrypy.tools.json_in()
    @cherrypy.tools.json_out()
    def add_bank_account(self):
        if cherrypy.request.method != 'POST':
            raise cherrypy.HTTPError(405)

        data = cherrypy.request.json
        account = BankAccount(
            name=data['name'],
            bank_name=data['bank_name'],
            account_number=data['account_number'],
            currency=data.get('currency', 'USD')
        )
        self.session.add(account)
        self.session.commit()
        return {'status': 'success', 'id': account.id}

    # Add OPTIONS method handler for CORS preflight
    @cherrypy.expose
    def add_bank_account_options(self):
        cherrypy.response.headers['Allow'] = 'POST, OPTIONS'
        cherrypy.response.headers['Access-Control-Allow-Headers'] = 'Content-Type'
        return ''

    # Accounts Endpoints
    @cherrypy.expose
    @cherrypy.tools.json_out()
    def accounts(self):
        if cherrypy.request.method != 'GET':
            raise cherrypy.HTTPError(405)

        accounts = self.session.query(Account).all()
        return [{
            'id': a.id,
            'name': a.name,
            'code': a.code,
            'type': a.account_type,
            'balance': float(a.balance) if a.balance else 0
        } for a in accounts]

    @cherrypy.expose
    @cherrypy.tools.json_in()
    @cherrypy.tools.json_out()
    def add_account(self):
        if cherrypy.request.method != 'POST':
            raise cherrypy.HTTPError(405)

        data = cherrypy.request.json
        account = Account(
            name=data['name'],
            account_type=data['type'],
            code=data['code'],
            parent_id=data.get('parent_id')
        )
        self.session.add(account)
        self.session.commit()
        return {'status': 'success', 'id': account.id}

    # Journal Entries Endpoints
    @cherrypy.expose
    @cherrypy.tools.json_in()
    @cherrypy.tools.json_out()
    def add_journal_entry(self):
        if cherrypy.request.method != 'POST':
            raise cherrypy.HTTPError(405)

        data = cherrypy.request.json
        total_debit = sum(line['amount'] for line in data['lines'] if line['is_debit'])
        total_credit = sum(line['amount'] for line in data['lines'] if not line['is_debit'])

        if abs(total_debit - total_credit) > 0.01:
            return {'status': 'error', 'message': 'Debits and credits must balance'}

        entry = JournalEntry(
            date=datetime.strptime(data['date'], '%Y-%m-%d').date(),
            reference=data.get('reference', ''),
            description=data.get('description', '')
        )
        self.session.add(entry)

        for line_data in data['lines']:
            line = JournalEntryLine(
                journal_entry=entry,
                account_id=line_data['account_id'],
                amount=line_data['amount'],
                is_debit=line_data['is_debit']
            )
            self.session.add(line)

            account = self.session.query(Account).get(line_data['account_id'])
            if line_data['is_debit']:
                account.balance += line_data['amount']
            else:
                account.balance -= line_data['amount']

        self.session.commit()
        return {'status': 'success', 'id': entry.id}

    @cherrypy.expose
    @cherrypy.tools.json_out()
    def journal_entries(self):
        if cherrypy.request.method != 'GET':
            raise cherrypy.HTTPError(405)

        entries = self.session.query(JournalEntry).all()
        return [{
            'id': e.id,
            'date': e.date.isoformat(),
            'description': e.description,
            'reference': e.reference,
            'lines': [{
                'account_id': l.account_id,
                'amount': float(l.amount),
                'is_debit': l.is_debit
            } for l in e.lines]
        } for e in entries]

    # Add default OPTIONS handler for all endpoints
    @cherrypy.expose
    def default(self, *args, **kwargs):
        if cherrypy.request.method == 'OPTIONS':
            cherrypy.response.headers['Allow'] = 'GET, POST, OPTIONS'
            cherrypy.response.headers['Access-Control-Allow-Headers'] = 'Content-Type'
            return ''
        raise cherrypy.HTTPError(404)