from pandas import DataFrame
import pandas as pd

# switch off warnings
pd.options.mode.chained_assignment = None


# main logic function
def main(result_file = 'output.csv', vlan_file = 'vlans.csv', requests_file = 'requests.csv'):
    # final list of elements
    out_list = [('request_id', []), ('device_id', []), ('primary_port', []), ('vlan_id', [])]

    # get files: with vlans data and requests data
    vlan_csv, requests_csv = read_data(vlan_file, requests_file)
    # division vlan_csv into two files
    # only_primary_port_devices - devices with primary port
    # device_primary - pairs of dataframes with devices available for redundancy
    only_primary_port_devices, device_primary = get_devices_info(vlan_csv)

    for request_data in requests_csv.itertuples():
        # processing of non redundant requests
        if request_data.redundant == 0:
                # from primary devices get minimal vlan value
                minimal_vlan_id = only_primary_port_devices[only_primary_port_devices.vlan_id == only_primary_port_devices.vlan_id.min()]

                # from minimal vlan for id is chosen a minimal device id
                minimal_device_id = minimal_vlan_id[minimal_vlan_id.device_id == minimal_vlan_id.device_id.min()]

                # drop
                only_primary_port_devices = only_primary_port_devices.drop(minimal_device_id.index)
                try:
                    device_primary = device_primary.drop(minimal_device_id.index)
                except ValueError:
                    pass

                # adding data in dict
                out_list[0][1].append(request_data.request_id)
                out_list[1][1].append(int(minimal_device_id.device_id.values[0]))
                out_list[2][1].append(1)
                out_list[3][1].append(int(minimal_device_id.vlan_id.values[0]))

        # processing of redundant requests
        elif request_data.redundant == 1:
            # if we have available pair vlan IDs
            if not device_primary.empty:
                # getiing minimal ids vlan value
                minimal_primary_vlan_id = device_primary[device_primary.vlan_id == device_primary.vlan_id.min()]

                #  device id is gotten from the number of minimal vlan ids
                minimal_primary_device_id = minimal_primary_vlan_id[minimal_primary_vlan_id.device_id == minimal_primary_vlan_id.device_id.min()]

                # drop
                only_primary_port_devices = only_primary_port_devices.drop(minimal_primary_device_id.index)
                device_primary = device_primary.drop(minimal_primary_device_id.index)

                # adding in dict data about minimal_primary_vlan_id
                out_list[0][1].append(request_data.request_id)
                out_list[1][1].append(int(minimal_primary_device_id.device_id.values[0]))
                out_list[2][1].append(1)
                out_list[3][1].append(int(minimal_primary_device_id.vlan_id.values[0]))

                # adding in dict data about minimal_secondary_vlan_id
                out_list[0][1].append(request_data.request_id)
                out_list[1][1].append(int(minimal_primary_device_id.device_id.values[0]))
                out_list[2][1].append(0)
                out_list[3][1].append(int(minimal_primary_device_id.vlan_id.values[0]))

    # create DataFrame from dict and write it into a file
    pd.DataFrame.from_items(out_list).sort_values(by=['request_id','primary_port']).to_csv(result_file, index=False, header=True, columns=['request_id', 'device_id', 'primary_port', 'vlan_id'])


# returning of the redundancy devices list and list of devices with primary port
def get_devices_info(vlan_csv):
    primary_results = DataFrame()

    # creating of three lists: a list with devices primary ports and devices secondary ports
    primary_port_devices = vlan_csv[vlan_csv.primary_port == 1]
    only_primary_port_devices = primary_port_devices
    secondary_port_devices = vlan_csv[vlan_csv.primary_port == 0]

    for devices in vlan_csv.device_id.unique():
        primary_port_device = primary_port_devices[(primary_port_devices.device_id == devices)]
        secondary_port_device = secondary_port_devices[(secondary_port_devices.device_id == devices)]

        primary_port_devices['redundancy_able'] = primary_port_device.vlan_id.isin(secondary_port_device.vlan_id)

        primary_results = primary_results.append(primary_port_devices[(primary_port_devices.redundancy_able == True)])

    return only_primary_port_devices[['device_id', 'vlan_id']], primary_results[['device_id', 'vlan_id']]


# reading data from files and cleaning it
def read_data(vlan_file = 'vlans.csv', requests_file = 'requests.csv'):
    vlan_csv = DataFrame(pd.read_csv(vlan_file)).dropna(how='any')
    requests_csv = DataFrame(pd.read_csv(requests_file)).dropna(how='any')

    return vlan_csv, requests_csv

if __name__ == '__main__':
    main()