#!/usr/bin/env python

"""Miscellaneous data features."""

__author__ = "Théo de la Hogue"
__credits__ = []
__copyright__ = "Copyright 2023, Ecole Nationale de l'Aviation Civile (ENAC)"
__license__ = "BSD"

from typing import TypeVar, Tuple, Any
import os
import importlib
from inspect import getmembers, getmodule
import collections
import json
import ast
import bisect
import threading
import math
import time

import pandas
import numpy
import matplotlib.pyplot as mpyplot
import matplotlib.patches as mpatches
from colorama import Style, Fore

TimeStampType = TypeVar('TimeStamp', int, float)
"""Type definition for timestamp as integer or float values."""

DataType = TypeVar('Data')
"""Type definition for data to store anything in time."""

TimeStampedBufferType = TypeVar('TimeStampedBuffer', bound="TimeStampedBuffer")
# Type definition for type annotation convenience

def module_path(obj) -> str:
    """
    Get object module path.

    Returns:
        module path
    """
    return obj.__class__.__module__

class JsonEncoder(json.JSONEncoder):
    """Specific ArGaze JSON Encoder."""

    def default(self, obj):
        """default implementation to serialize object."""

        # numpy cases
        if isinstance(obj, numpy.integer):
            return int(obj)

        elif isinstance(obj, numpy.floating):
            return float(obj)

        elif isinstance(obj, numpy.ndarray):
            return obj.tolist()

        # default case
        try:

            return json.JSONEncoder.default(self, obj)

        # class case
        except:

            # ignore attribute starting with _
            public_dict = {}

            for k, v in vars(obj).items():
                
                if not k.startswith('_'):
                    
                    # numpy cases
                    if isinstance(v, numpy.integer):
                        v = int(v)

                    elif isinstance(v, numpy.floating):
                        v = float(v)

                    elif isinstance(v, numpy.ndarray):
                        v = v.tolist()

                    public_dict[k] = v

            return public_dict

class TimeStampedBuffer(collections.OrderedDict):
    """Ordered dictionary to handle timestamped data.
    ```
        {
            timestamp1: data1,
            timestamp2: data2,
            ...
        }
    ```

    !!! warning
    
        Timestamps must be numbers.

    !!! warning "Timestamps are not sorted internally"
        
        Data are considered to be stored according at their coming time.
    """

    def __new__(cls, args = None):
        """Inheritance"""

        return super(TimeStampedBuffer, cls).__new__(cls)

    def __setitem__(self, ts: TimeStampType, data: DataType):
        """Store data at given timestamp."""

        assert(type(ts) == int or type(ts) == float)

        super().__setitem__(ts, data)

    def __repr__(self):
        """String representation"""

        return json.dumps(self, ensure_ascii=False, cls=JsonEncoder)

    def __str__(self):
        """String representation"""

        return json.dumps(self, ensure_ascii=False, cls=JsonEncoder)

    def append(self, timestamped_buffer: TimeStampedBufferType) -> TimeStampedBufferType:
        """Append a timestamped buffer."""

        for ts, value in timestamped_buffer.items():
            self[ts] = value

        return self

    @property
    def first(self) -> Tuple[TimeStampType, DataType]:
        """Easing access to first item."""

        return list(self.items())[0]

    def pop_first(self) -> Tuple[TimeStampType, DataType]:
        """Easing FIFO access mode."""

        return self.popitem(last=False)

    def pop_last_until(self, ts: TimeStampType) -> Tuple[TimeStampType, DataType]:
        """Pop all item until a given timestamped value and return the first after."""

        # get last item before given timestamp
        earliest_ts, earliest_value = self.get_last_until(ts)

        first_ts, first_value = self.first

        while first_ts < earliest_ts:
            self.pop_first()
            first_ts, first_value = self.first
            
        return first_ts, first_value

    def pop_last_before(self, ts: TimeStampType) -> Tuple[TimeStampType, DataType]:
        """Pop all item before a given timestamped value and return the last one."""

        # get last item before given timestamp
        earliest_ts, earliest_value = self.get_last_before(ts)

        popep_ts, poped_value = self.pop_first()

        while popep_ts != earliest_ts:
            popep_ts, poped_value = self.pop_first()

        return popep_ts, poped_value

    @property
    def last(self) -> Tuple[TimeStampType, DataType]:
        """Easing access to last item."""

        return list(self.items())[-1]

    def pop_last(self) -> Tuple[TimeStampType, DataType]:
        """Easing FIFO access mode."""

        return self.popitem(last=True)

    def get_first_from(self, ts) -> Tuple[TimeStampType, DataType]:
        """Retreive first item timestamp from a given timestamp value."""

        ts_list = list(self.keys())
        first_from_index = bisect.bisect_left(ts_list, ts)

        if first_from_index < len(self):

            first_from_ts = ts_list[first_from_index]
            
            return first_from_ts, self[first_from_ts]
            
        else:
            
            raise KeyError(f'No data stored after {ts} timestamp.')

    def get_last_before(self, ts) -> Tuple[TimeStampType, DataType]:
        """Retreive last item timestamp before a given timestamp value."""

        ts_list = list(self.keys())
        last_before_index = bisect.bisect_left(ts_list, ts) - 1

        if last_before_index >= 0:

            last_before_ts = ts_list[last_before_index]
            
            return last_before_ts, self[last_before_ts]
            
        else:
            
            raise KeyError(f'No data stored before {ts} timestamp.')
        
    def get_last_until(self, ts) -> Tuple[TimeStampType, DataType]:
        """Retreive last item timestamp until a given timestamp value."""

        ts_list = list(self.keys())
        last_until_index = bisect.bisect_right(ts_list, ts) - 1

        if last_until_index >= 0:

            last_until_ts = ts_list[last_until_index]
            
            return last_until_ts, self[last_until_ts]
            
        else:
            
            raise KeyError(f'No data stored until {ts} timestamp.')

    @classmethod
    def from_json(self, json_filepath: str) -> TimeStampedBufferType:
        """Create a TimeStampedBuffer from .json file."""

        with open(json_filepath, encoding='utf-8') as ts_buffer_file:

            json_buffer = json.load(ts_buffer_file)

            return TimeStampedBuffer({ast.literal_eval(ts_str): json_buffer[ts_str] for ts_str in json_buffer})

    def to_json(self, json_filepath: str):
        """Save a TimeStampedBuffer to .json file."""

        with open(json_filepath, 'w', encoding='utf-8') as ts_buffer_file:

            json.dump(self, ts_buffer_file, ensure_ascii=False, cls=JsonEncoder)

    @classmethod
    def from_dataframe(self, dataframe: pandas.DataFrame, exclude=[]) -> TimeStampedBufferType:
        """Create a TimeStampedBuffer from [Pandas DataFrame](https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.html)."""

        dataframe.drop(exclude, inplace=True, axis=True)

        assert(dataframe.index.name == 'timestamp')

        return TimeStampedBuffer(dataframe.to_dict('index'))

    def as_dataframe(self, exclude=[], split={}) -> pandas.DataFrame:
        """Convert as [Pandas DataFrame](https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.html).  
        
        The optional *split* argument allows tuple values to be stored in dedicated columns.  
        For example: to convert {"point": (0, 0)} data as two separated "x" and "y" columns, use split={"point": ["x", "y"]}  

        !!! warning "Values must be dictionaries"
        
            Each key is stored as a column name.

        !!! note

            Timestamps are stored as index column called 'timestamp'.
        """

        df = pandas.DataFrame.from_dict(self.values())

        # Exclude columns
        df.drop(exclude, inplace=True, axis=True)

        # Split columns
        if len(split) > 0:

            splited_columns = []
            
            for column in df.columns:

                if column in split.keys():

                    df[split[column]] = pandas.DataFrame(df[column].tolist(), index=df.index)
                    df.drop(column, inplace=True, axis=True)

                    for new_column in split[column]:

                        splited_columns.append(new_column)

                else:

                    splited_columns.append(column)

            # Reorder splited columns
            df = df[splited_columns]

        # Append timestamps as index column
        df['timestamp'] = self.keys()
        df.set_index('timestamp', inplace=True)

        return df

    def plot(self, names=[], colors=[], split={}, samples=None) -> list:
        """Plot as [matplotlib](https://matplotlib.org/) time chart."""

        df = self.as_dataframe(split=split)
        legend_patches = []

        # decimate data
        if samples != None:

            if samples < len(df):

                step = int(len(df) / samples) + 1
                df = df.iloc[::step, :]

        for name, color in zip(names, colors):

            markerline, stemlines, baseline = mpyplot.stem(df.index, df[name])
            mpyplot.setp(markerline, color=color, linewidth=1, markersize = 1)
            mpyplot.setp(stemlines, color=color, linewidth=1)
            mpyplot.setp(baseline, color=color, linewidth=1)

            legend_patches.append(mpatches.Patch(color=color, label=name.upper()))

        return legend_patches

class DataDictionary(dict):
    """Enable dot.notation access to dictionary attributes"""

    __getattr__ = dict.get
    __setattr__ = dict.__setitem__
    __delattr__ = dict.__delitem__

class SharedObject():
    """Abstract class to enable multiple threads sharing and timestamp management."""

    def __init__(self):

        self._lock = threading.Lock()
        self._timestamp = math.nan
        self._execution_times = {}
        self._exceptions = {}

    @property
    def lock(self) -> threading.Lock:
        """Get shared object lock object."""
        return self._lock

    @property
    def timestamp(self) -> int|float:
        """Get shared object timestamp."""
        self._lock.acquire()
        timestamp = self._timestamp
        self._lock.release()

        return timestamp

    @timestamp.setter
    def timestamp(self, timestamp: int|float):
        """Set shared object timestamp."""
        self._lock.acquire()
        self._timestamp = timestamp
        self._lock.release()

    def untimestamp(self):
        """Reset shared object timestamp."""
        self._lock.acquire()
        self._timestamp = math.nan
        self._lock.release()

    @property
    def timestamped(self) -> bool:
        """Is the object timestamped?"""
        self._lock.acquire()
        timestamped = not math.isnan(self._timestamp)
        self._lock.release()

        return timestamped

class PipelineStepObject():
    """
    Define class to assess pipeline step methods execution time and observe them.
    """

    def __init__(self, name: str = None, observers: dict = None):
        """Initialize PipelineStepObject

        Parameters:
            observers: dictionary with observers objects.
        """

        # Init private attribute
        self.__name = name
        self.__observers = observers if observers is not None else {}
        self.__execution_times = {}
        self.__properties = {}

        # parent attribute will be setup later by parent it self
        self.__parent = None

    def __enter__(self):
        """At with statement start."""

        # Start observers
        for observer_name, observer in self.__observers.items():

            observer.__enter__()

        return self

    def __exit__(self, type, value, traceback):
        """At with statement end."""

        # End observers
        for observer_name, observer in self.__observers.items():

            observer.__exit__(type, value, traceback)

    @property
    def name(self) -> str:
        """Get layer's name."""
        return self.__name

    @property
    def parent(self) -> object:
        """Get layer's parent object."""
        return self.__parent

    @parent.setter
    def parent(self, parent: object):
        """Set layer's parent object."""
        self.__parent = parent

    @property
    def observers(self) -> dict:
        """Get pipeline step object observers dictionary."""
        return self.__observers

    @property
    def execution_times(self):
        """Get pipeline step object observers execution times dictionary."""
        return self.__execution_times
    
    def as_dict(self) -> dict:
        """Export PipelineStepObject attributes as dictionary.

        Returns:
            object_data: dictionary with pipeline step object attributes values.
        """
        return {
            "name": self.__name,
            "observers": self.__observers
        }

    @classmethod
    def from_dict(cls, object_data: dict, working_directory: str = None) -> object:
        """Load PipelineStepObject attributes from dictionary.

        Returns:
            object_data: dictionary with pipeline step object attributes values.
            working_directory: folder path where to load files when a dictionary value is a relative filepath.
        """

        # Load name
        try:

            new_name = object_data.pop('name')

        except KeyError:

            new_name = None
        
        # Load observers
        new_observers = {}

        try:

            new_observers_value = object_data.pop('observers')

            # str: relative path to file
            if type(new_observers_value) == str:

                filepath = os.path.join(working_directory, new_observers_value)
                file_format = filepath.split('.')[-1]

                # Python file format
                if file_format == 'py':

                    observer_module_path = new_observers_value.split('.')[0]

                    observer_module = importlib.import_module(observer_module_path)

                    new_observers = observer_module.__observers__

             # dict: instanciate ready-made argaze observers
            elif type(new_observers_value) == dict:

                for observer_type, observer_data in new_observers_value.items():

                    new_observers[observer_type] = eval(f'{observer_type}(**observer_data)')

        except KeyError:

            pass

        # Create pipeline step object
        return PipelineStepObject(\
            new_name, \
            new_observers \
            )

    @classmethod
    def from_json(self, json_filepath: str) -> object:
        """
        Define abstract method to load pipeline step object from .json file.

        Parameters:
            json_filepath: path to json file
        """
        raise NotImplementedError('from_json() method not implemented')

    def to_json(self, json_filepath: str = None):
        """Save pipeline step object into .json file."""

        # Remember file path to ease rewriting
        if json_filepath is not None:

            self.__json_filepath = json_filepath

        # Open file
        with open(self.__json_filepath, 'w', encoding='utf-8') as object_file:

            json.dump({DataFeatures.module_path(self):DataFeatures.JsonEncoder().default(self)}, object_file, ensure_ascii=False, indent=4)

            # QUESTION: maybe we need two saving mode?
            #json.dump(self, object_file, ensure_ascii=False, indent=4, cls=DataFeatures.JsonEncoder)

    def __str__(self) -> str:
        """
        String representation of pipeline step object.
        
        Returns:
            String representation
        """
        
        tabs = self.tabulation  
        output = f'{Fore.GREEN}{Style.BRIGHT}{self.__class__.__module__}.{self.__class__.__name__}{Style.RESET_ALL}\n'

        if self.__name is not None:
            output += f'{tabs}\t{Style.BRIGHT}name{Style.RESET_ALL}: {self.__name}\n'

        if self.__parent is not None:
            output += f'{tabs}\t{Style.BRIGHT}parent{Style.RESET_ALL}: {self.__parent.name}\n'

        if len(self.__observers):
            output += f'{tabs}\t{Style.BRIGHT}observers{Style.RESET_ALL}:\n'
            for name, observer in self.__observers.items():
                output += f'{tabs}\t  - {Fore.RED}{name}{Style.RESET_ALL}: {Fore.GREEN}{Style.BRIGHT}{observer.__class__.__module__}.{observer.__class__.__name__}{Style.RESET_ALL}\n'

        for name, value in self.properties:

            output += f'{tabs}\t{Style.BRIGHT}{name}{Style.RESET_ALL}: '

            if type(value) == dict:

                output += '\n'

                for k, v in value.items():

                    output += f'{tabs}\t  - {Fore.RED}{k}{Style.RESET_ALL}: {v}\n'

            elif type(value) == numpy.ndarray:

                output += f'numpy.array{value.shape}\n'

            elif type(value) == pandas.DataFrame:

                output += f'pandas.DataFrame{value.shape}\n'

            else:

                output += f'{value}'

                if output[-1] != '\n':

                    output += '\n'

        return output

    @property
    def tabulation(self) -> str:
        """Edit tabulation string according parents number."""

        tabs = ''
        parent = self.__parent

        while (parent is not None):

            tabs += '\t'
            parent = parent.parent

        return tabs

    @property
    def properties(self) -> list:
        """Iterate over pipeline step properties values."""

        for name, item in self.__class__.__dict__.items(): 

            if isinstance(item, property):

                yield name, getattr(self, name)
        
        for base in self.__class__.__bases__:

            if base != PipelineStepObject and base != SharedObject:

                for name, item in base.__dict__.items(): 

                    if isinstance(item, property):

                        yield name, getattr(self, name)

def PipelineStepMethod(method):
    """Define a decorator use into PipelineStepObject class to declare pipeline method.

    !!! danger
        PipelineStepMethod must have a timestamp as first argument.
    """

    def wrapper(self, timestamp, *args, **kw):
        """Wrap pipeline step method to measure execution time."""

        # Initialize execution time assessment
        start = time.perf_counter()
        
        try:

            # Execute wrapped method
            result = method(self, timestamp, *args, **kw)

        finally:

            # Measure execution time
            self.execution_times[method.__name__] = (time.perf_counter() - start) * 1e3

        # Notify observers that method has been called
        subscription_name = f'on_{method.__name__}'

        for observer_name, observer in self.observers.items():

            # Does the observer cares about this method?
            if subscription_name in dir(observer): 

                subscription = getattr(observer, subscription_name)

                # Call subscription
                subscription(timestamp, self)

        return result

    return wrapper

class PipelineStepObserver():
    """Define abstract class to observe pipeline step object use.

    !!! note
        To subscribe to a method call, the inherited class simply needs to define 'on_<method_name>' functions with timestamp and object argument.
    """

    def __enter__(self):
        """
        Define abstract __enter__ method to use observer as a context.

        !!! warning
            This method is called provided that the observed PipelineStepObject is created as a context using a with statement.
        """
        return self

    def __exit__(self, type, value, traceback):
        """
        Define abstract __exit__ method to use observer as a context.

        !!! warning
            This method is called provided that the observed PipelineStepObject is created as a context using a with statement.
        """
        pass