# -*- coding: utf-8 -*-

# Copyright (c) 2016-2022 by University of Kassel and Fraunhofer Institute for Energy Economics
# and Energy System Technology (IEE), Kassel. All rights reserved.
import copy
import functools
import os
from time import perf_counter
from types import FunctionType

import numpy as np
import pandas as pd
from collections.abc import Iterable
from pandapower.io_utils import JSONSerializableClass
from pandapower.io_utils import mkdirs_if_not_existent
from pandapower.pd2ppc import _pd2ppc
from pandapower.pypower.idx_bus import VM, VA, NONE, BUS_TYPE
from pandapower.run import _init_runpp_options
from pandapower.timeseries.read_batch_results import v_to_i_s, get_batch_line_results, get_batch_trafo3w_results, \
    get_batch_trafo_results, get_batch_bus_results

try:
    import pandaplan.core.pplog as pplog
except ImportError:
    import logging as pplog
logger = pplog.getLogger(__name__)


class OutputWriter(JSONSerializableClass):
    """
    The OutputWriter class is used to store and format specific outputs from a time series calculation.

    It contains a python-dictionary *output* which is a container for result DataFrames or arbitrary information you
    would like to store. By default a pandas DataFrame is initialized for the key *Parameters*, which has the columns
    "time_step", "controller_unstable", "powerflow_failed".

    To simple log outputs during a time series simulation use **ow.log_variable(table, column)** where table is the name
    of the (result) table, e.g. "res_bus", and column the name of the column, e.g. "vm_pu".

    More sophisticated outputs can be added as well since for each value to be stored a function is
    added to the *output_list* which is called at the end of each time step.
    The function reads the calculation results and returns the desired values to store.
    The function is expected to return scalar value by default. If more values are returned, the function should have
    "n_columns" as a paramter (see example below for logging of cost function values).
    These values are then stored in the *output* DataFrame in a column named after the function you implemented.
    Such a function can be used to store only some information of the power flow results, like the highest values
    of the line loading in a time step or the mean values. Check the "advanced time series example" jupyter notebook
    for an example.

    INPUT:
        **net** - The pandapower format network

        **time_steps** (list) - time_steps to calculate as a list (or range)

    OPTIONAL:

        **output_path** (string, None) - Path to a folder where the output is written to.

        **output_file_type** (string, ".p") - output filetype to use.
        Allowed file extensions: [.xls, .xlsx, .csv, .p, .json]
        Note: XLS has a maximum number of 256 rows.

        **csv_separator** (string, ";") - The separator used when writing to a csv file

        **write_time** (int, None) - Time to save periodically to disk in minutes. Deactivated by default

        **log_variables** (list, None) - list of tuples with (table, column) values to  be logged by output writer.
        Defaults are: res_bus.vm_pu and res_line.loading_percent. Additional variables can be added later on
        with ow.log_variable or removed with ow.remove_log_variable



    EXAMPLE:
        >>> from pandapower.timeseries.output_writer import OutputWriter
        >>> from pandapower.networks as nw
        >>> net = nw.simple_four_bus_system()
        >>> ow = OutputWriter(net) # create an OutputWriter
        >>> ow.log_variable('res_bus', 'vm_pu') # add logging for bus voltage magnitudes
        >>> ow.log_variable('res_line', 'loading_percent') # add logging for line loadings in percent
        >>>  # Getting the cost function slope for each time step:
        >>> def cost_logging(result, n_columns=2):
        >>>      return array([result[i][0][2] for i in range(len(result))])
        >>> ow.log_variable("pwl_cost", "points", eval_function=cost_logging)



    """

    def __init__(self, net, time_steps=None, output_path=None, output_file_type=".p", write_time=None,
                 log_variables=None, csv_separator=";"):
        super().__init__()
        self.output_path = output_path
        self.output_file_type = output_file_type
        self.write_time = write_time
        self.log_variables = log_variables
        # these are the default log variables which are added if log_variables is None
        self.default_log_variables = [("res_bus", "vm_pu"), ("res_line", "loading_percent")]
        self._add_log_defaults()

        self.csv_separator = csv_separator
        if write_time is not None:
            self.write_time *= 60.0  # convert to seconds

        # init the matrix and the list of output functions
        self.output = dict()
        # internal results stored as numpy arrays in dict. Is created from output_list
        self.np_results = dict()
        # output list contains functools.partial with tables, variables, index...
        self.output_list = []
        # real time is tracked to save results to disk regularly
        self.cur_realtime = perf_counter()
        # total time steps to calculate
        self.time_steps = time_steps
        # add output_writer to net
        self.add_to_net(net, element="output_writer", index=0, overwrite=True)
        # inits dataframes and numpy arrays which store results
        # self.init_all()
        # Saves all parameters as object attributes to store in JSON

    def __str__(self):
        # return self.__class__.__name__
        return self.__repr__()

    def __repr__(self):
        s = "%s: writes output to '%s'" % (self.__class__.__name__, self.output_path)
        s += " and logs:"
        for output in self.log_variables:
            table, variable = output[0], output[1]
            s += "\n'" + str(table) + "." + str(variable) + "'"
        return s

    def _monkey_patch(self, method, new):
        from types import MethodType
        setattr(self, method, MethodType(new, self))

    def _add_log_defaults(self):
        if self.log_variables is None:
            self.log_variables = list()
            self.log_variables = copy.copy(self.default_log_variables)
        if not isinstance(self.log_variables, list):
            raise TypeError("log_variables must be None or a list of tuples like [('res_bus', 'vm_pu')]")

    def init_log_variables(self, net):
        """
        inits the log variables given to output writer.
        log_variables is a list with tuples of DataFrame columns to log.
        Example: [("res_bus", "vm_pu"), ("res_bus", "va_degree")]

        If None are given the defaults are:
        res_bus.vm_pu
        res_line.loading_percent
        """
        _init_log_variable = functools.partial(self._init_log_variable, net)
        for log_args in self.log_variables:
            # add log variable
            _init_log_variable(*log_args)

    def init_all(self, net):
        if isinstance(self.time_steps, Iterable):
            self.output = dict()
            self.np_results = dict()
            self.output_list = list()
            self.init_log_variables(net)
            self.init_timesteps(self.time_steps)
            self._init_np_results()
            self._init_output()

        else:
            logger.debug("Time steps not set at init ")

    def _init_output(self):
        self.output = dict()
        # init parameters
        self.output["Parameters"] = pd.DataFrame(False, index=self.time_steps,
                                                 columns=["time_step", "controller_unstable",
                                                          "powerflow_failed"])
        self.output["Parameters"].loc[:, "time_step"] = self.time_steps

    def _init_np_results(self):
        # inits numpy array (contains results)
        self.np_results = dict()
        for partial_func in self.output_list:
            self._init_np_array(partial_func)

    def _save_separate(self, append):

        for partial in self.output_list:
            if isinstance(partial, tuple):
                # if batch output is used
                table = partial[0]
                variable = partial[1]
            else:
                # if output_list contains functools.partial
                table = partial.args[0]
                variable = partial.args[1]
            if table != "Parameters":
                file_path = os.path.join(self.output_path, table)
                mkdirs_if_not_existent(file_path)
                if append:
                    file_name = str(variable) + "_" + str(self.cur_realtime) + self.output_file_type
                else:
                    file_name = str(variable) + self.output_file_type
                file_path = os.path.join(file_path, file_name)
                data = self.output[self._get_output_name(table, variable)]
                if self.output_file_type == ".json":
                    data.to_json(file_path)
                elif self.output_file_type == ".p":
                    data.to_pickle(file_path)
                elif self.output_file_type in [".xls", ".xlsx"]:
                    try:
                        data.to_excel(file_path)
                    except ValueError as e:
                        if data.shape[1] > 255:
                            raise ValueError("pandas.to_excel() is not capable to handle large data" +
                                             "with more than 255 columns. Please use other " +
                                             "file_extensions instead, e.g. 'json'.")
                        else:
                            raise ValueError(e)
                elif self.output_file_type == ".csv":
                    data.to_csv(file_path, sep=self.csv_separator)

    def dump_to_file(self, net, append=False, recycle_options=None):
        """
        Save the output to separate files in output_path with the file_type output_file_type. This is called after
        the time series simulation by default.

           **append** (bool, False) - Option for appending instead of overwriting the file
        """
        save_single = False
        self._np_to_pd()
        if recycle_options not in [None, False]:
            self.get_batch_outputs(net, recycle_options)
        if self.output_path is not None:
            try:
                if save_single and self.output_file_type in [".xls", ".xlsx"]:
                    self._save_single_xls_sheet(append)
                elif self.output_file_type in [".csv", ".xls", ".xlsx", ".json", ".p"]:
                    self._save_separate(append)
                else:
                    raise UserWarning(
                        "Specify output file with .csv, .xls, .xlsx, .p or .json ending")
                if append:
                    self._init_output()

            except Exception:
                raise

    def dump(self, net, recycle_options=None):
        append = False if self.time_step == self.time_steps[-1] else True
        self.dump_to_file(net, append=append, recycle_options=recycle_options)
        self.cur_realtime = perf_counter()  # reset real time counter for next period

    def save_results(self, net, time_step, pf_converged, ctrl_converged, recycle_options=None):
        # Saves the results of the current time step to a matrix,
        # using the output functions in the self.output_list

        # remember the last time step
        self.time_step = time_step

        # add an entry to the output matrix if something failed
        if not pf_converged:
            self.save_nans_to_parameters()
            self.output["Parameters"].loc[time_step, "powerflow_failed"] = True
        elif not ctrl_converged:
            self.output["Parameters"].loc[time_step, "controller_unstable"] = True
        else:
            self.save_to_parameters()

        # if write time is exceeded or it is the last time step, data is written
        if self.write_time is not None:
            if perf_counter() - self.cur_realtime > self.write_time:
                self.dump(net)
        if self.time_step == self.time_steps[-1]:
            self.dump(net, recycle_options)

    def save_to_parameters(self):
        # Saves the results of the current time step to self.output,
        # using the output functions in the self.output_list

        for of in self.output_list:
            try:
                of()
            except:
                import traceback
                traceback.print_exc()
                logger.error("Error in output function! Stored NaN for '%s' in time-step %i"
                             % (of.__name__, self.time_step))
                self.save_nans_to_parameters()

    def save_nans_to_parameters(self):
        # Saves NaNs to for the given time step.
        time_step_idx = self.time_step_lookup[self.time_step]
        for of in self.output_list:
            self.output["Parameters"].loc[time_step_idx, of.__name__] = np.NaN

    def remove_log_variable(self, table, variable=None):
        """
        removes a logged variable from outputs

        INPUT:
        **table** (str) - name of the DataFrame table (example: "res_bus")

        OPTIONAL:
        **variable** (str, None) - column name of the DataFrame table (example: "vm_pu"). If None all are variables of
        table are removed

        """
        # remove variables from list
        if variable is not None:
            self.output_list = [o for o in self.output_list if not (o.args[0] == table and o.args[1] == variable)]
            self.log_variables = [o for o in self.log_variables if not (o[0] == table and o[1] == variable)]
        else:
            self.output_list = [o for o in self.output_list if not (o.args[0] == table)]
            self.log_variables = [o for o in self.log_variables if not (o[0] == table)]
        # init output container again
        self._init_np_results()

    def log_variable(self, table, variable, index=None, eval_function=None, eval_name=None):
        """
        Adds a variable to log during simulation and appends it to output_list.
        INPUT:

        **table** (str) - The DataFrame table where the variable is located as a string (e.g. "res_bus")

        **variable** (str) -  variable that should be logged as string (e.g. "p_mw")

        OPTIONAL:

        **index** (iterable, None) - Can be either one index or a list of indices, or a numpy array of indices,
        or a pandas Index, or a pandas Series (e.g. net.load.bus) for which
        the variable will be logged. If no index is given, the variable will be logged for all elements in the table

        **eval_function** (function, None) - A function to be applied on the table / variable / index combination.
        example: pd.min or pd.mean

        **eval_name** (str, None) - The name for an applied function. It *must* be unique.
                                    If the name is None the name consists of the table, variable, index and eval function
                                    example: "max_load_p_mw_values"

        EXAMPLE:
            >>> ow.log_variable('res_bus', 'vm_pu') # add logging for bus voltage magnitudes
            >>> ow.log_variable('res_line', 'loading_percent', index=[0, 2, 5]) # add logging for line loading of lines with indices 0, 2, 5
            >>> ow.log_variable('res_line', 'loading_percent', eval_function=pd.max) # get the highest line loading only

            # Getting the cost function slope for each time step:
            >>> def cost_logging(result, n_columns=2):
            >>>      return array([result[i][0][2] for i in range(len(result))])
            >>> ow.log_variable("pwl_cost", "points", eval_function=cost_logging)

        """
        del_indices = list()
        append_args = set()
        append = True
        # check if new log_variable is already in log_variables. If so either append or delete
        for i, log_args in enumerate(self.log_variables):
            if len(log_args) > 4 and eval_name is not None and log_args[4] == eval_name:
                logger.warning("eval_name '{}' already exists for table '{}' and variable '{}'. "
                                 "Please choose a unique eval_name. "
                               "I'll use the default instead.".format(eval_name, log_args[0], log_args[1]))
                eval_name = None
            if log_args[0] == table and log_args[1] == variable:
                # table and variable exist in log_variables
                if eval_function is not None or eval_name is not None:
                    append = True
                    continue
                if len(log_args) == 2 and eval_function is None:
                    # everything from table / variable is logged
                    append = False
                    continue
                if log_args[2] is not None and index is not None and eval_function is None:
                    # if index is given and an index was given before extend the index and get unique
                    log_args[2] = set(log_args[2].extend(index))
                else:
                    del_indices.append(i)
                    append_args.add((table, variable))
                    append = False

        for i in del_indices:
            del self.log_variables[i]
        for log_arg in append_args:
            self.log_variables.append(log_arg)
        if append:
            self.log_variables.append((table, variable, index, eval_function, eval_name))

    def _init_ppc_logging(self, table, variable, net, eval_function, eval_name):
        var_name = self._get_output_name(table, variable)
        ppc = net["_ppc"]
        if ppc is None:
            # if no ppc is in net-> create one
            options = dict(algorithm='nr', calculate_voltage_angles="auto", init="auto",
                           max_iteration="auto", tolerance_mva=1e-8, trafo_model="t",
                           trafo_loading="current", enforce_q_lims=False, check_connectivity=True,
                           voltage_depend_loads=True, consider_line_temperature=False)
            _init_runpp_options(net, **options)
            ppc, _ = _pd2ppc(net)
            net["_ppc"] = ppc
        index = list(range(sum(ppc['bus'][:, BUS_TYPE] != NONE)))
        self._append_output_list(table, variable, net, index, eval_function, eval_name, var_name, func=self._log_ppc)
        return index

    def _init_log_variable(self, net, table, variable, index=None, eval_function=None, eval_name=None):
        if "ppc" in table:
            index = self._init_ppc_logging(table, variable, net, eval_function, eval_name)

        if np.any(pd.isnull(index)):
            # check how many elements there are in net
            index = net[table.split("res_")[-1].replace("_3ph", "")].index
        if not hasattr(index, '__iter__'):
            index = [index]
        if isinstance(index, (np.ndarray, pd.Index, pd.Series)):
            index = index.tolist()
        if eval_function is not None and eval_name is None:
            eval_name = "%s.%s.%s.%s" % (table, variable, str(index), eval_function.__name__)
        if eval_function is None and eval_name is not None:
            logger.info("'eval_name' is to give a name in case of evaluation functions. Since " +
                        "no function is given for eval_name '%s', " % eval_name +
                        "eval_name is neglected.")
            eval_name = None
        if eval_name is not None and eval_function is not None:
            if isinstance(eval_function, FunctionType):
                if "n_columns" in eval_function.__code__.co_varnames:
                    logger.info("'eval_name' is to give a name in case of single value evaluation functions. Since " +
                                "n_columns is given as a parameter of the evaluation function, the given for eval_name "
                                "'%s', " % eval_name + "eval_name is neglected.")
                    eval_name = None

        # var_name = self._get_hash((table, variable, index, eval_function))
        var_name = self._get_output_name(table, variable)
        idx = self._get_same_log_variable_partial_func_idx(table, variable, eval_function,
                                                           eval_name)
        if idx is not None:
            self._append_existing_log_variable_partial_func(idx, index)
        else:
            self._append_output_list(table, variable, net, index, eval_function, eval_name, var_name)

    def _get_same_log_variable_partial_func_idx(self, table, variable, eval_function, eval_name):
        """ Returns the position index in self.output_list of partial_func which has the same table
        and variable and no evaluation function. """
        if eval_function is None and eval_name is None:
            for i, partial_func in enumerate(self.output_list):
                partial_args = partial_func.args
                match = partial_args[0] == table
                match &= partial_args[1] == variable
                if match:
                    return i

    def _append_existing_log_variable_partial_func(self, idx, index):
        """ Appends the index of existing, same partial_func in output_list. """
        for i in index:
            if i not in self.output_list[idx].args[3]:
                self.output_list[idx].args[3].append(i)

    def _append_output_list(self, table, variable, net, index, eval_function, eval_name, var_name, func=None):
        """ Appends the output_list by an additional partial_func. """
        func = self._log if func is None else func
        partial_func = functools.partial(func, table, variable, net, index, eval_function, eval_name)
        partial_func.__name__ = var_name
        self.output_list.append(partial_func)
        if self.time_steps is not None:
            self._init_np_array(partial_func)

    def _log(self, table, variable, net, index, eval_function=None, eval_name=None):
        try:
            # ToDo: Create a mask for the numpy array in the beginning and use this one for getting the values. Faster
            if net[table].index.equals(pd.Index(index)):
                # if index equals all values -> get numpy array directly
                result = net[table][variable].values
            else:
                # get by loc (slow)
                result = net[table].loc[index, variable].values

            if eval_function is not None:
                result = eval_function(result)

            # save results to numpy array
            time_step_idx = self.time_step_lookup[self.time_step]
            hash_name = self._get_np_name((table, variable, net, index, eval_function, eval_name))
            self.np_results[hash_name][time_step_idx, :] = result

        except Exception as e:
            logger.error("Error at index %s for %s[%s]: %s" % (index, table, variable, e))

    def _log_ppc(self, table, variable, net, index, eval_function=None, eval_name=None):
        # custom log function fo ppc results
        ppci = net["_ppc"]["internal"]
        if variable == "vm":
            v = VM
        elif variable == "va":
            v = VA
        else:
            raise NotImplementedError("No other variable implemented yet.")
        result = ppci[table.split("_")[-1]][:, v]
        if eval_function is not None:
            result = eval_function(result)

        # save results to numpy array
        time_step_idx = self.time_step_lookup[self.time_step]
        hash_name = self._get_np_name((table, variable, net, index, eval_function, eval_name))
        self.np_results[hash_name][time_step_idx, :] = result

    def _np_to_pd(self):
        # convert numpy arrays (faster so save results) into pd Dataframes (user friendly)
        # intended use: At the end of time series simulation write results to pandas

        for partial_func in self.output_list:
            (table, variable, net, index, eval_func, eval_name) = partial_func.args
            # res_name = self._get_hash(table, variable)
            res_name = self._get_output_name(table, variable)
            np_name = self._get_np_name(partial_func.args)
            columns = index
            if eval_name is not None and eval_func is not None:
                if isinstance(eval_func, FunctionType):
                    if "n_columns" not in eval_func.__code__.co_varnames:
                        columns = [eval_name]
                else:
                    columns = [eval_name]

            res_df = pd.DataFrame(self.np_results[np_name], index=self.time_steps, columns=columns)
            if res_name in self.output and eval_name is not None:
                try:
                    self.output[res_name] = pd.concat([self.output[res_name], res_df], axis=1,
                                                      sort=False)
                except TypeError:
                    # pandas legacy < 0.21
                    self.output[res_name] = pd.concat([self.output[res_name], res_df], axis=1)
            else:
                # new dataframe
                self.output[res_name] = res_df

    def _get_output_name(self, table, variable):
        return "%s.%s" % (table, variable)

    def _get_np_name(self, partial_args):
        eval_name = partial_args[5]
        if eval_name is not None:
            return eval_name
        else:
            table = partial_args[0]
            variable = partial_args[1]
            return "%s.%s" % (table, variable)

    def _save_single_xls_sheet(self, append):
        # ToDo: implement save to a single sheet
        raise NotImplementedError("Sorry not implemented yet")

    def init_timesteps(self, time_steps):
        self.time_steps = time_steps
        self.time_step = time_steps[0]
        self.time_step_lookup = {t: idx for idx, t in enumerate(time_steps)}

    def _init_np_array(self, partial_func):
        (table, variable, net, index, eval_function, eval_name) = partial_func.args
        hash_name = self._get_np_name(partial_func.args)
        n_columns = len(index)
        if eval_function is not None:
            n_columns = 1
            if isinstance(eval_function, FunctionType):
                if "n_columns" in eval_function.__code__.co_varnames:
                    n_columns = eval_function.__defaults__[0]
        self.np_results[hash_name] = np.zeros((len(self.time_steps), n_columns))

    def get_batch_outputs(self, net, recycle_options):
        # read the results in batch from vm, va (ppci values)

        if isinstance(recycle_options["batch_read"], list) and len(recycle_options["batch_read"]):
            # vm, va is without out of service elements
            vm, va = self.output["ppc_bus.vm"], self.output["ppc_bus.va"]
            _, s_abs, i_abs = v_to_i_s(net, vm, va)
            results = dict()
            new_output_list = list()
            for table, variable in recycle_options["batch_read"]:
                if table == "res_line" and "res_line" not in results:
                    i_ka, i_from_ka, i_to_ka, loading_percent = get_batch_line_results(net, i_abs)
                    results["res_line"] = dict(i_ka=i_ka, i_from_ka=i_from_ka, i_to_ka=i_to_ka,
                                               loading_percent=loading_percent)
                elif table == "res_trafo" and "res_trafo" not in results:
                    i_ka, i_hv_ka, i_lv_ka, s_mva, loading_percent = get_batch_trafo_results(net, i_abs, s_abs)
                    results["res_trafo"] = dict(i_ka=i_ka, i_hv_ka=i_hv_ka, i_lv_ka=i_lv_ka,
                                                loading_percent=loading_percent)
                elif table == "res_trafo3w":
                    i_h, i_m, i_l, loading_percent = get_batch_trafo3w_results(net, i_abs, s_abs)
                    results["res_trafo3w"] = dict(i_h=i_h, i_m=i_m, i_l=i_l, loading_percent=loading_percent)
                elif table == "res_bus" and "res_bus" not in results:
                    vm_full, va_full = get_batch_bus_results(net, vm, va)
                    results["res_bus"] = dict(vm_pu=vm_full, va_degree=va_full)
                else:
                    raise ValueError("Something went wrong")
                output_name = "%s.%s" % (table, variable)
                # convert to dataframe
                self.output[output_name] = pd.DataFrame(data=results[table][variable], index=self.time_steps)
                new_output_list.append((table, variable))
            self.output_list = new_output_list
