#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Fri Sep 20 15:33:17 2019

@author: tanya
"""

import os
import sys
import numpy as np
sys.path.append(os.getcwd())

class ParseMapping:
    '''
    '''
    def __init__(self, mapping_path: str, log_name: str = "ParseMapping",
                 source: str = "original_name", target: str = "mongo_name",
                 target_collection: str = "mongo_collection"):
        '''
        '''
        import json
        from cdplib.log import Log

        self._log = Log('Parse Mapping')

        if not os.path.isfile(mapping_path):
            err = "Mapping not found "+mapping_path
            self._log.error(err)
            raise FileNotFoundError(err)

        try:
            with open(mapping_path, "r") as f:
                self._mapping = json.load(f)

        except Exception as e:
            err = ("Could not load mapping. " + mapping_path +
                   "Exit with error {}".format(e))
            self._log.error(err)
            raise Exception(err)

        self._source = source
        self._target = target
        self._target_collection = target_collection

    def get_field_mapping(self) -> dict:
        '''
        '''
        assert(all([set([self._source, self._target]) <= set(d)
                    for d in self._mapping]))

        return {d[self._source]: d[self._target] for d in self._mapping}

    def _get_fields_satistisfying_condition(self, key: str, value) -> list:
        '''
        '''
        assert(all([self._source in d for d in self._mapping])),\
            "Invalid from field"

        return [d[self._source] for d in self._mapping
                if (key in d) and (d[key] == value)]

    def get_required_fields(self) -> list:
        '''
        '''
        return self._get_fields_satistisfying_condition(key="required",
                                                        value=1)

    def get_date_fields(self) -> list:
        '''
        '''
        return self._get_fields_satistisfying_condition(key="type",
                                                        value="Date")

    def get_fields_restricted_to_collecton(self, collection_name: str) -> list:
        '''
        '''
        return self._get_fields_satistisfying_condition(key=self._target_collection,
                                                        value=collection_name)

    def _get_info(self, key: str, value=None) -> dict:
        '''
        '''
        assert(all([self._source in d for d in self._mapping])),\
            "Invalid from field"

        return {d[self._source]: d[key] for d in self._mapping
                if (key in d) and ((value is not None)
                and (d[key] == value)) or (key in d)}

    def get_default_values(self) -> dict:
        '''
        '''
        return self._get_info(key="default_values")

    def get_date_formats(self) -> dict:
        '''
        '''
        return self._get_info(key="date_format")
    
    def get_internal_names(self) -> dict:
        '''
        '''
 
        if all(["internal_name" in d for d in self._mapping]):
            internal_names = [d["internal_name"] for d in self._mapping]
    
        elif all(["internal_name" not in d for d in self._mapping]):
            internal_names = list(range(len(self._mapping)))


        else:
            err = ("Incorrectly filled mapping. Internal names should "
                   "either be in all or in neither of the fields")
            self._log.error(err)
            raise Exception(err)

        return internal_names

    def get_mongo_names(self) -> dict:
        '''
        '''
        if all(["mongo_name" in d for d in self._mapping]):
            mongo_names = [d["mongo_name"] for d in self._mapping]

        elif all(["mongo_name" not in d for d in self._mapping]):
            mongo_names = list(range(len(self._mapping)))

        else:
            err = ("Incorrectly filled mapping. Mongo names should "
                   "either be in all or in neither of the fields")
            self._log.error(err)
            raise Exception(err)

        return mongo_names

    def get_types(self) -> dict:
        '''
        '''
        return self._get_info(key="type")

    def get_python_types(self) -> dict:
        '''
        '''
        sql_to_python_dtypes = {
                "Text": str,
                "Date": np.dtype('<M8[ns]'),
                "Double": float,
                "Integer": int
                }

        sql_types = self.get_types()

        return {k: sql_to_python_dtypes[v] for k, v in sql_types.items()}

    def get_value_mappings(self) -> dict:
        '''
        '''
        return self._get_info(key="value_mapping")

    def get_column_numbers(self) -> list:
        '''
        '''
        if all(["column_number" in d for d in self._mapping]):
            column_numbers = [d["column_number"] for d in self._mapping]

        elif all(["column_number" not in d for d in self._mapping]):
            column_numbers = list(range(len(self._mapping)))

        else:
            err = ("Incorrectly filled mapping. Column numbers should ",
                   "either in all or in neither of the fields")
            self._log.err(err)
            raise Exception(err)

        return column_numbers


if __name__ == "__main__":

    mapping_path = os.path.join(".", "migration_mappings", "rs0_mapping.json")

    if os.path.isfile(mapping_path):

        print("found mapping path")

        parser = ParseMapping(mapping_path, source="internal_name",
                              target="mongo_name")

        internal_to_mongo_mapping = parser.get_field_mapping()

        original_to_internal_mapping = parser.get_field_mapping()

        default_values = parser.get_default_values()

        types = parser.get_types()

        column_numbers = parser.get_column_numbers()

        print("Done testing!")