path: root/src/argaze/GazeFeatures.py

#!/usr/bin/env python

"""Generic gaze data and class definitions."""

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

from typing import TypeVar, Tuple, Any
from dataclasses import dataclass, field
import math
import ast
import json
from inspect import getmembers

from argaze import DataStructures

import numpy
import pandas
import cv2

GazePositionType = TypeVar('GazePosition', bound="GazePosition")
# Type definition for type annotation convenience

@dataclass(frozen=True)
class GazePosition():
    """Define gaze position as a tuple of coordinates with precision."""

    value: tuple[int | float] = field(default=(0, 0))
    """Position's value."""

    precision: float = field(default=0., kw_only=True)
    """Position's precision represents the radius of a circle around \
    this gaze position value where other same gaze position measurements could be."""

    def __getitem__(self, axis: int) -> int | float:
        """Get position value along a particular axis."""

        return self.value[axis]

    def __iter__(self) -> iter:
        """Iterate over each position value axis."""

        return iter(self.value)
    
    def __len__(self) -> int:
        """Number of axis in position value."""

        return len(self.value)

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

        return json.dumps(self, ensure_ascii = False, default=vars)

    def __mul__(self, value) -> GazePositionType:
        """Multiply gaze position."""

        return GazePosition(numpy.array(self.value) * value, precision= self.precision * numpy.linalg.norm(value))

    def __array__(self):
        """Cast as numpy array."""

        return numpy.array(self.value)

    @property
    def valid(self) -> bool:
        """Is the precision not None?"""

        return self.precision is not None

    def distance(self, gaze_position) -> float:
        """Distance to another gaze positions."""

        distance = (self.value[0] - gaze_position.value[0])**2 + (self.value[1] - gaze_position.value[1])**2
        distance = numpy.sqrt(distance)

        return distance

    def overlap(self, gaze_position, both=False) -> float:
        """Does this gaze position overlap another gaze position considering its precision?
        Set both to True to test if the other gaze position overlaps this one too."""

        distance = (self.value[0] - gaze_position.value[0])**2 + (self.value[1] - gaze_position.value[1])**2
        distance = numpy.sqrt(distance)

        if both:
            return distance < min(self.precision, gaze_position.precision)
        else:
            return distance < self.precision

    def draw(self, image: numpy.array, color=(0, 255, 255), draw_precision=True):
        """Draw gaze position point and precision circle."""

        if self.valid:

            int_value = (int(self.value[0]), int(self.value[1]))

            # Draw point at position
            cv2.circle(image, int_value, 2, color, -1)

            # Draw precision circle
            if self.precision > 0 and draw_precision:
                cv2.circle(image, int_value, round(self.precision), color, 1)

class UnvalidGazePosition(GazePosition):
    """Unvalid gaze position."""

    def __init__(self, message=None):

        self.message = message

        super().__init__((None, None), precision=None)

TimeStampedGazePositionsType = TypeVar('TimeStampedGazePositions', bound="TimeStampedGazePositions")
# Type definition for type annotation convenience

class TimeStampedGazePositions(DataStructures.TimeStampedBuffer):
    """Define timestamped buffer to store gaze positions."""

    def __setitem__(self, key, value: GazePosition|dict):
        """Force GazePosition storage."""

        # Convert dict into GazePosition
        if type(value) == dict:

            assert(set(['value', 'precision']).issubset(value.keys()))

            if math.isnan(value['precision']):

                if 'message' in value.keys():

                    value = UnvalidGazePosition(value['message'])

                else :

                    value = UnvalidGazePosition()

            else:

                value = GazePosition(value['value'], precision=value['precision'])

        assert(type(value) == GazePosition or type(value) == UnvalidGazePosition)

        super().__setitem__(key, value)

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

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

            json_buffer = json.load(ts_buffer_file)

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

    @classmethod
    def from_dataframe(self, dataframe: pandas.DataFrame, timestamp: str, x: str, y: str, precision: str = None) -> TimeStampedGazePositionsType:
        """Create a TimeStampedGazePositions from [Pandas DataFrame](https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.html).

        Parameters:
            timestamp: specific timestamp column label.
            x: specific x column label.
            y: specific y column label.
            precision: specific precision column label if exist.
        """

        # Select columns
        if precision:

            df = dataframe[[timestamp, x, y, precision]]

        else:

            df = dataframe[[timestamp, x, y]]

        # Merge x and y columns into one 'value' column
        df['value'] = tuple(zip(df[x], df[y]))
        df.drop(columns= [x, y], inplace=True, axis=1)

        # Handle precision data
        if precision:

             # Rename precision column into 'precision' column
            df.rename(columns={precision: 'precision'}, inplace=True)

        else:

            # Append a precision column where precision is NaN if value is a tuple of NaN else 0
            df['precision'] = df.apply(lambda row: numpy.nan if math.isnan(row.value[0]) or math.isnan(row.value[1]) else 0, axis=True)

        # Rename timestamp column into 'timestamp' column then use it as index
        df.rename(columns={timestamp: 'timestamp'}, inplace=True)
        df.set_index('timestamp', inplace=True)
        
        # Filter duplicate timestamps
        df = df[df.index.duplicated() == False]

        return TimeStampedGazePositions(df.to_dict('index'))

GazeMovementType = TypeVar('GazeMovement', bound="GazeMovement")
# Type definition for type annotation convenience

@dataclass(frozen=True)
class GazeMovement():
    """Define abstract gaze movement class as a buffer of timestamped positions."""

    positions: TimeStampedGazePositions
    """All timestamp gaze positions."""

    duration: float = field(init=False)
    """Inferred duration from first and last timestamps."""

    amplitude: float = field(init=False)
    """Inferred amplitude from first and last positions."""

    finished: bool = field(init=False, default=False)
    """Is the movement finished?"""

    def __post_init__(self):

        if self.valid:

            start_position_ts, start_position = self.positions.first
            end_position_ts, end_position = self.positions.last

            # Update frozen duration attribute
            object.__setattr__(self, 'duration', end_position_ts - start_position_ts)

            _, start_position = self.positions.first
            _, end_position = self.positions.last

            amplitude = numpy.linalg.norm( numpy.array(start_position.value) - numpy.array(end_position.value))

            # Update frozen amplitude attribute
            object.__setattr__(self, 'amplitude', amplitude)

        else:

            # Update frozen duration attribute
            object.__setattr__(self, 'duration', -1)

            # Update frozen amplitude attribute
            object.__setattr__(self, 'amplitude', -1)

    def __str__(self) -> str:
        """String display"""

        if self.valid:

            output = f'{type(self)}:\n\tduration={self.duration}\n\tsize={len(self.positions)}'

            for ts, position in self.positions.items():

                output += f'\n\t{ts}:\n\t\tvalue={position.value},\n\t\tprecision={position.precision}'

            return output

    @property
    def valid(self) -> bool:
        """Is there positions?"""

        return len(self.positions) > 0

    def finish(self) -> GazeMovementType:
        """Set gaze movement as finished"""

        # Update frozen finished attribute
        object.__setattr__(self, 'finished', True)

        return self

    def draw_positions(self, image: numpy.array, color=(0, 55, 55)):
        """Draw gaze movement positions"""

        gaze_positions = self.positions.copy()

        while len(gaze_positions) >= 2:

            ts_start, start_gaze_position = gaze_positions.pop_first()
            ts_next, next_gaze_position = gaze_positions.first

            # Draw start gaze
            start_gaze_position.draw(image, draw_precision=False)

            # Draw movement from start to next
            cv2.line(image, (int(start_gaze_position[0]), int(start_gaze_position[1])), (int(next_gaze_position[0]), int(next_gaze_position[1])), color, 1)

    def draw(self, image: numpy.array, color):
        """Draw gaze movement into image."""

        raise NotImplementedError('draw() method not implemented')

class UnvalidGazeMovement(GazeMovement):
    """Unvalid gaze movement."""

    def __init__(self, message=None):

        self.message = message

        super().__init__(TimeStampedGazePositions())

    def draw(self, image: numpy.array, color):
        
        pass

FixationType = TypeVar('Fixation', bound="Fixation")
# Type definition for type annotation convenience

class Fixation(GazeMovement):
    """Define abstract fixation as gaze movement."""

    focus: tuple = field(init=False)
    """Representative position of the fixation."""

    def __post_init__(self):

        super().__post_init__()

    def merge(self, fixation) -> FixationType:
        """Merge another fixation into this fixation."""

        raise NotImplementedError('merge() method not implemented')

def is_fixation(gaze_movement):
    """Is a gaze movement a fixation?"""

    return type(gaze_movement).__bases__[0] == Fixation or type(gaze_movement) == Fixation

class Saccade(GazeMovement):
    """Define abstract saccade as gaze movement."""

    def __post_init__(self):

        super().__post_init__()

def is_saccade(gaze_movement):
    """Is a gaze movement a saccade?"""

    return type(gaze_movement).__bases__[0] == Saccade or type(gaze_movement) == Saccade

TimeStampedGazeMovementsType = TypeVar('TimeStampedGazeMovements', bound="TimeStampedGazeMovements")
# Type definition for type annotation convenience

class TimeStampedGazeMovements(DataStructures.TimeStampedBuffer):
    """Define timestamped buffer to store gaze movements."""

    def __setitem__(self, key, value: GazeMovement):
        """Force value to be or inherit from GazeMovement."""

        assert(isinstance(value, GazeMovement) or type(value).__bases__[0] == Fixation or type(value).__bases__[0] == Saccade)

        super().__setitem__(key, value)

    def __str__(self):

        output = ''
        for ts, item in self.items():

            output += f'\n{item}'

        return output

GazeStatusType = TypeVar('GazeStatus', bound="GazeStatus")
# Type definition for type annotation convenience

@dataclass(frozen=True)
class GazeStatus(GazePosition):
    """Define gaze status as a gaze position belonging to an identified and indexed gaze movement."""

    movement_type: str = field(kw_only=True)
    """GazeMovement type to which gaze position belongs."""

    movement_index: int = field(kw_only=True)
    """GazeMovement index to which gaze positon belongs."""

    @classmethod
    def from_position(cls, gaze_position: GazePosition, movement_type: str, movement_index: int) -> GazeStatusType:
        """Initialize from a gaze position instance."""

        return cls(gaze_position.value, precision=gaze_position.precision, movement_type=movement_type, movement_index=movement_index)

TimeStampedGazeStatusType = TypeVar('TimeStampedGazeStatus', bound="TimeStampedGazeStatus")
# Type definition for type annotation convenience

class TimeStampedGazeStatus(DataStructures.TimeStampedBuffer):
    """Define timestamped buffer to store gaze status."""

    def __setitem__(self, key, value: GazeStatus):
        super().__setitem__(key, value)

class GazeMovementIdentifier():
    """Abstract class to define what should provide a gaze movement identifier."""

    def identify(self, ts, gaze_position, terminate=False) -> Tuple[GazeMovementType, GazeMovementType]:
        """Identify gaze movement from successive timestamped gaze positions. 
        Each identified gaze movement should share its first/last gaze position with previous/next gaze movement.

        Parameters:
            ts:
            gaze_position:
            terminate: allows to notify identification algorithm that given gaze position will be the last one.
        
        Returns:
            finished_gaze_movement: identified gaze movement once it is finished otherwise it returns unvalid gaze movement.
        """

        raise NotImplementedError('identify() method not implemented')

    @property
    def current_gaze_movement(self) -> GazeMovementType:
        """Get currently identified gaze movement."""

        raise NotImplementedError('current_gaze_movement getter not implemented')

    @property
    def current_fixation(self) -> GazeMovementType:
        """Get currently identified fixation."""

        raise NotImplementedError('current_fixation getter not implemented')

    @property
    def current_saccade(self) -> GazeMovementType:
        """Get currently identified saccade."""

        raise NotImplementedError('current_saccade getter not implemented')

    def browse(self, ts_gaze_positions: TimeStampedGazePositions) -> Tuple[TimeStampedGazeMovementsType, TimeStampedGazeMovementsType, TimeStampedGazeStatusType]:
        """Identify fixations and saccades browsing timestamped gaze positions."""

        assert(type(ts_gaze_positions) == TimeStampedGazePositions)

        ts_fixations = TimeStampedGazeMovements()
        ts_saccades = TimeStampedGazeMovements()
        ts_status = TimeStampedGazeStatus()

        # Get last ts to terminate identification on last gaze position
        last_ts, _ = ts_gaze_positions.last

        # Iterate on gaze positions
        for ts, gaze_position in ts_gaze_positions.items():

            finished_gaze_movement = self.identify(ts, gaze_position, terminate=(ts == last_ts))

            if is_fixation(finished_gaze_movement):

                start_ts, start_position = finished_gaze_movement.positions.first

                ts_fixations[start_ts] = finished_gaze_movement

                # First gaze movement position is always shared with previous gaze movement
                for ts, position in finished_gaze_movement.positions.items():

                    gaze_status = GazeStatus.from_position(position, 'Fixation', len(ts_fixations))

                    if ts != start_ts:

                        ts_status[ts] = [gaze_status]

                    else:

                        try:

                            ts_status[start_ts].append(gaze_status)

                        except KeyError:

                            ts_status[start_ts] = [gaze_status]

            elif is_saccade(finished_gaze_movement):

                start_ts, start_position = finished_gaze_movement.positions.first

                ts_saccades[start_ts] = finished_gaze_movement

                # First gaze movement position is always shared with previous gaze movement
                for ts, position in finished_gaze_movement.positions.items():

                    gaze_status = GazeStatus.from_position(position, 'Saccade', len(ts_saccades))

                    if ts != start_ts:

                        ts_status[ts] = [gaze_status]

                    else:

                        try:

                            ts_status[start_ts].append(gaze_status)

                        except KeyError:

                            ts_status[start_ts] = [gaze_status]

            else:

                continue

        return ts_fixations, ts_saccades, ts_status

    def __call__(self, ts_gaze_positions: TimeStampedGazePositions) -> Tuple[int|float, GazeMovementType]:
        """GazeMovement generator.

        Parameters:
            ts_gaze_positions: timestamped gaze positions to process.

        Returns:
            timestamp: first gaze position date of identified gaze movement
            finished_gaze_movement: identified gaze movement once it is finished
        """

        assert(type(ts_gaze_positions) == TimeStampedGazePositions)

        # Get last ts to terminate identification on last gaze position
        last_ts, _ = ts_gaze_positions.last

        # Iterate on gaze positions
        for ts, gaze_position in ts_gaze_positions.items():

            finished_gaze_movement = self.identify(ts, gaze_position, terminate=(ts == last_ts))

            if finished_gaze_movement.valid:

                start_ts, start_position = finished_gaze_movement.positions.first

                yield start_ts, finished_gaze_movement

ScanStepType = TypeVar('ScanStep', bound="ScanStep")
# Type definition for type annotation convenience

class ScanStepError(Exception):
    """Exception raised at ScanStepError creation if a aoi scan step doesn't start by a fixation or doesn't end by a saccade."""

    def __init__(self, message):  

        super().__init__(message)

@dataclass(frozen=True)
class ScanStep():
    """Define a scan step as a fixation and a consecutive saccade.
    .. warning::
       Scan step have to start by a fixation and then end by a saccade."""

    first_fixation: Fixation
    """A fixation that comes before the next saccade."""

    last_saccade: Saccade
    """A saccade that comes after the previous fixation."""

    def __post_init__(self):

        # First movement have to be a fixation
        if not is_fixation(self.first_fixation):

            raise ScanStepError('First step movement is not a fixation')

        # Last movement have to be a saccade
        if not is_saccade(self.last_saccade):
            
            raise ScanStepError('Last step movement is not a saccade')

    @property
    def duration(self):
        """Time spent on AOI."""

        # Timestamp of first position of first fixation
        first_ts, _ = self.first_fixation.positions.first 

        # Timestamp of first position of last saccade
        last_ts, _ = self.last_saccade.positions.first 

        return last_ts - first_ts

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

class ScanPath(list):
    """List of scan steps."""

    def __init__(self):

        super().__init__()
        
        self.__last_fixation = None

    def append_saccade(self, ts, saccade) -> ScanStepType:
        """Append new saccade to scan path and return last new scan step if one have been created."""

        # Ignore saccade if no fixation came before
        if self.__last_fixation != None:

            try: 

                # Edit new step
                new_step = ScanStep(self.__last_fixation, saccade)

                # Append new step
                super().append(new_step)

                # Return new step
                return new_step

            finally:

                # Clear last fixation
                self.__last_fixation = None

    def append_fixation(self, ts, fixation):
        """Append new fixation to scan path.
        !!! warning
                Consecutives fixations are ignored keeping the last fixation"""

        self.__last_fixation = fixation

    def draw(self, image: numpy.array, fixation_color=(255, 255, 255), saccade_color=(255, 255, 255), deepness=0):
        """Draw scan path into image."""

        last_step = None
        for step in self[-deepness:]:

            if last_step != None:

                cv2.line(image, (int(last_step.first_fixation.focus[0]), int(last_step.first_fixation.focus[1])), (int(step.first_fixation.focus[0]), int(step.first_fixation.focus[1])), saccade_color, 2)

                last_step.first_fixation.draw(image, fixation_color)

            last_step = step

class ScanPathAnalyzer():
    """Abstract class to define what should provide a scan path analyzer."""

    def __init__(self):

        self.__properties = [name for (name, value) in getmembers(type(self), lambda v: isinstance(v, property))]

    @property
    def analysis(self) -> dict:

        analysis = {}

        for p in self.__properties:

            if p != 'analysis':

                analysis[p] = getattr(self, p)

        return analysis

    def analyze(self, scan_path: ScanPathType):
        """Analyze scan path."""

        raise NotImplementedError('analyze() method not implemented')

AOIScanStepType = TypeVar('AOIScanStep', bound="AOIScanStep")
# Type definition for type annotation convenience

class AOIScanStepError(Exception):
    """Exception raised at AOIScanStepError creation if a aoi scan step doesn't start by a fixation or doesn't end by a saccade."""

    def __init__(self, message, aoi=''):  

        super().__init__(message)

        self.aoi = aoi

@dataclass(frozen=True)
class AOIScanStep():
    """Define a aoi scan step as a set of successive gaze movements onto a same AOI.
    .. warning::
       Aoi scan step have to start by a fixation and then end by a saccade."""

    movements: TimeStampedGazeMovements
    """All movements over an AOI and the last saccade that comes out."""

    aoi: str = field(default='')
    """AOI name."""

    letter: str = field(default='')
    """AOI unique letter to ease sequence analysis."""

    def __post_init__(self):

        # First movement have to be a fixation
        if not is_fixation(self.first_fixation):

            raise AOIScanStepError('First step movement is not a fixation', self.aoi)

        # Last movement have to be a saccade
        if not is_saccade(self.last_saccade):
            
            raise AOIScanStepError('Last step movement is not a saccade', self.aoi)

    @property
    def first_fixation(self):
        """First fixation on AOI."""

        _, first_movement = self.movements.first
        return first_movement

    @property
    def last_saccade(self):
        """Last saccade that comes out AOI."""

        _, last_movement = self.movements.last
        return last_movement

    @property
    def duration(self):
        """Time spent on AOI."""

        # Timestamp of first position of first fixation
        first_ts, _ = self.first_fixation.positions.first 

        # Timestamp of first position of last saccade
        last_ts, _ = self.last_saccade.positions.first 

        return last_ts - first_ts

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

class AOIScanPath(list):
    """List of aoi scan steps over successive aoi."""

    def __init__(self, expected_aois: list[str] = []):

        super().__init__()
        
        self.expected_aois = expected_aois
        
    def __repr__(self):
        """String representation."""

        return str(super())

    def __get_aoi_letter(self, aoi):

        try :

            return self.__aoi_letter[aoi]

        except KeyError:

            letter = chr(self.__index)
            self.__aoi_letter[aoi] = letter
            self.__index += 1
            return letter

    def get_letter_aoi(self, letter):
        """Get which aoi is related to an unique letter."""

        return self.__letter_aoi[letter]

    def __str__(self) -> str:
        """Convert aoi scan path into a string with unique letter per aoi step."""

        sequence = ''
        for step in self:
            sequence += step.letter

        return sequence

    @property
    def expected_aois(self):
        """List of all expected aoi."""

        return self.__expected_aois

    @expected_aois.setter
    def expected_aois(self, expected_aois: list[str] = []):
        """Edit list of all expected aoi.

        !!! warning
                This will clear the AOIScanPath
        """
        self.clear()

        self.__expected_aois = expected_aois
        self.__movements = TimeStampedGazeMovements()
        self.__current_aoi = ''
        self.__index = ord('A')
        self.__aoi_letter = {}
        self.__letter_aoi = {}

        size = len(self.__expected_aois)
        self.__transition_matrix = pandas.DataFrame(numpy.zeros((size, size)), index=self.__expected_aois, columns=self.__expected_aois)

    @property
    def current_aoi(self):
        """AOI name of aoi scan step under construction"""

        return self.__current_aoi

    @property
    def transition_matrix(self) -> pandas.DataFrame:
        """[Pandas DataFrame](https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.html) where indexes are transition departures and columns are transition destinations."""

        return self.__transition_matrix

    def append_saccade(self, ts, saccade):
        """Append new saccade to aoi scan path."""

        # Ignore saccade if no fixation have been stored before
        if len(self.__movements) > 0:

            self.__movements[ts] = saccade

    def append_fixation(self, ts, fixation, looked_aoi: str) -> bool:
        """Append new fixation to aoi scan path and return last new aoi scan step if one have been created.

        !!! warning
                It could raise AOIScanStepError"""

        if looked_aoi not in self.__expected_aois:

            raise AOIScanStepError('AOI not expected', looked_aoi)

        # Is it fixation onto a new aoi?
        if looked_aoi != self.__current_aoi and len(self.__movements) > 0:

            try: 

                # Edit unique letter per aoi
                letter = self.__get_aoi_letter(self.__current_aoi)

                # Remember which letter identify which aoi
                self.__letter_aoi[letter] = self.__current_aoi

                # Edit new step
                new_step = AOIScanStep(self.__movements, self.__current_aoi, letter)

                # Edit transition matrix
                if len(self) > 0:

                    # Increment [index: source, columns: destination] value
                    self.__transition_matrix.loc[self[-1].aoi, self.__current_aoi,] += 1

                # Append new step
                super().append(new_step)

                # Return new step
                return new_step

            finally:

                # Clear movements
                self.__movements = TimeStampedGazeMovements()

                # Append new fixation
                self.__movements[ts] = fixation

                # Remember new aoi
                self.__current_aoi = looked_aoi
        else:

            # Append new fixation
            self.__movements[ts] = fixation

            # Remember aoi
            self.__current_aoi = looked_aoi

            return None

    def fixations_count(self):
        """Get how many fixations are there in the scan path and how many fixation are there in each aoi."""

        scan_fixations_count = 0
        aoi_fixations_count = {aoi: 0 for aoi in self.__expected_aois}

        for aoi_scan_step in self:

            step_fixations_count = len(aoi_scan_step.movements) - 1 # -1: to ignore last saccade

            scan_fixations_count += step_fixations_count
            aoi_fixations_count[aoi_scan_step.aoi] += step_fixations_count
            
        return scan_fixations_count, aoi_fixations_count

class AOIScanPathAnalyzer():
    """Abstract class to define what should provide a aoi scan path analyzer."""

    def __init__(self):

        self.__properties = [name for (name, value) in getmembers(type(self), lambda v: isinstance(v, property))]

    @property
    def analysis(self) -> dict:

        analysis = {}

        for p in self.__properties:

            if p != 'analysis':
                
                analysis[p] = getattr(self, p)

        return analysis

    def analyze(self, aoi_scan_path: AOIScanPathType):
        """Analyze aoi scan path."""

        raise NotImplementedError('analyze() method not implemented')