#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from csv import DictWriter
from glob import glob
from ofxparse import OfxParser
from pathlib import Path

from decimal import Decimal
from bson.decimal128 import Decimal128

import logging
import os 
import pymongo
import time
import watchdog.events
import watchdog.observers

DATE_FORMAT = "%d/%m/%Y"

if 'WATCH_DIR' in os.environ:
    WATCH_DIR = os.environ['WATCH_DIR']
else:
    WATCH_DIR = '/mnt/data/'

PATTERN = '*.qfx'
BACKUP_DIR = 'Imported'
CONVERTED_DIR = 'Converted'

MONGO_URL = os.environ['DB_HOST']
MONGO_PORT = os.environ['DB_PORT']
MONGO_DB = os.environ['DB_NAME']
MONGO_COL = 'imported_transactions'
ACCOUNT_COL = 'accounts'

MONGO_URL = "mongodb://{}:{}".format(MONGO_URL, MONGO_PORT)
myclient = pymongo.MongoClient(MONGO_URL)
mydb = myclient[MONGO_DB]
mongo_col = mydb[MONGO_COL]
account_col = mydb[ACCOUNT_COL]

logging.basicConfig(format='%(asctime)s - %(message)s', level=logging.INFO)
logging.basicConfig(format='ERROR: %(asctime)s - %(message)s', level=logging.ERROR)

class Handler(watchdog.events.PatternMatchingEventHandler):
    def __init__(self):
        # Set the patterns for PatternMatchingEventHandler
        watchdog.events.PatternMatchingEventHandler.__init__(self, patterns=['*.qfx'],
                                                             ignore_directories=True, case_sensitive=False)
  
    @staticmethod
    def write_csv(statement, out_file):
        logging.info("Writing: " + out_file)

        if len(statement) == 0:
            logging.info("No transactions to write.")
            return

        fields = ['date', 'memo', 'category', 'amount', 'name']
        with open(out_file, 'w') as f:
            f.write("Date,Original Description,Category,Amount,Account Name")
            f.write("\r\n")
            writer = DictWriter(f, fieldnames=fields)
            for line in statement:
                writer.writerow(line)

    @staticmethod
    def transaction_exists(line):
        existing_trans = mongo_col.find_one(line)

        return existing_trans is not None

    @staticmethod
    def convert_decimal(dict_item):
    # This function iterates a dictionary looking for types of Decimal and converts them to Decimal128
    # Embedded dictionaries and lists are called recursively.
        if dict_item is None: return None

        for k, v in list(dict_item.items()):
            if isinstance(v, dict):
                Handler.convert_decimal(v)
            elif isinstance(v, list):
                for l in v:
                    Handler.convert_decimal(l)
            elif isinstance(v, Decimal):
                dict_item[k] = Decimal128(str(v))

        return dict_item

    @staticmethod
    def get_statement_from_qfx(qfx):

        account = account_col.find_one({"number": qfx.account.number})
        if account is None:
            logging.error("No account for account number {} exists. Create one and re-process the file".format(qfx.account.number))

        statement = []
        for transaction in qfx.account.statement.transactions:
           
            if transaction.payee.startswith("PENDING:"):
                continue

            line = {
                'date': transaction.date.strftime(DATE_FORMAT),
                'memo' : transaction.memo,
                'category': 'Uncategorised',
                'amount': transaction.amount,
                'name': account['name']
            }

            #mongo needs the decimal values in Decimal128, so create a version for it
            line_d128 = Handler.convert_decimal(line.copy())

            if Handler.transaction_exists(line_d128):
                continue

            statement.append(line)
            result = mongo_col.insert_one(line_d128)
            logging.info("New db entry stored: {}".format(result.inserted_id))

        return statement, account['name']    

    @staticmethod
    def unique_path(directory, name_pattern):
        counter = 0
        while True:
            counter += 1
            path = directory / name_pattern.format(counter)
            if not path.exists():
                return path

    def on_created(self, event):
        logging.info('File found: {}'.format(event.src_path))

        fileExists = False
        timeout = 0
        while not fileExists:
            fileExists = os.path.isfile(event.src_path)
            time.sleep(1)
            timeout += 1

            if timeout > 60:
                logging.error('Timeout waiting for file {} to exist. Aborting processing.'.format(event.src_path))
                return
        
        historicalSize = -1
        while (historicalSize != os.path.getsize(event.src_path)):
            logging.info('waiting for copy to finish....')
            historicalSize = os.path.getsize(event.src_path)
            time.sleep(1)

        logging.info("file copy has now finished")
        
        with open(event.src_path, 'r') as file:
            qfx = OfxParser.parse(file, fail_fast=False)
            statement, acct_name = Handler.get_statement_from_qfx(qfx)

            path = Path(event.src_path)
            path.resolve()

            converted_dir = path.parent / CONVERTED_DIR
            if not converted_dir.exists():
                converted_dir.mkdir()

            out_file = str(path.parent / CONVERTED_DIR / (acct_name + '-' + qfx.signon.dtserver + '.csv'))
            Handler.write_csv(statement, out_file)    

            #Now move the input file to backup
            archive_file_dir = path.parent / BACKUP_DIR
            archive_file = (path.stem + '{:04d}' + path.suffix)
            destination = Handler.unique_path(archive_file_dir, archive_file)

            if not archive_file_dir.exists():
                archive_file_dir.mkdir()

            if not destination.exists():
                path.replace(destination)

        logging.info("Processing successfully finished for {}".format(event.src_path))
  
if __name__ == "__main__":
    event_handler = Handler()
    observer = watchdog.observers.Observer()
    observer.schedule(event_handler, path=WATCH_DIR, recursive=False)

    observer.start()
    logging.info('Converter running, waiting for files in {}'.format(WATCH_DIR))
    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        observer.stop()
    observer.join()