#!/usr/bin/env python3
""" Alignments file functions for reading, writing and manipulating
    a serialized alignments file """

import logging
import os
from datetime import datetime

import cv2

from lib.faces_detect import rotate_landmarks
from lib import Serializer

logger = logging.getLogger(__name__)  # pylint: disable=invalid-name


class Alignments():
    """ Holds processes pertaining to the alignments file.

        folder:     folder alignments file is stored in
        filename:   Filename of alignments file excluding extension. If a
                    valid extension is provided, then it will be used to
                    decide the serializer, and the serializer argument will
                    be ignored.
        serializer: If provided, this will be the format that the data is
                    saved in (if data is to be saved). Can be 'json', 'pickle'
                    or 'yaml'
    """
    # pylint: disable=too-many-public-methods
    def __init__(self, folder, filename="alignments", serializer="json"):
        logger.debug("Initializing %s: (folder: '%s', filename: '%s', serializer: '%s')",
                     self.__class__.__name__, folder, filename, serializer)
        self.serializer = self.get_serializer(filename, serializer)
        self.file = self.get_location(folder, filename)

        self.data = self.load()
        self.update_legacy()
        logger.debug("Initialized %s", self.__class__.__name__)

    # << PROPERTIES >> #

    @property
    def frames_count(self):
        """ Return current frames count """
        retval = len(self.data)
        logger.trace(retval)
        return retval

    @property
    def faces_count(self):
        """ Return current faces count """
        retval = sum(len(faces) for faces in self.data.values())
        logger.trace(retval)
        return retval

    @property
    def have_alignments_file(self):
        """ Return whether an alignments file exists """
        retval = os.path.exists(self.file)
        logger.trace(retval)
        return retval

    @property
    def hashes_to_frame(self):
        """ Return a dict of each face_hash with their parent
            frame name(s) and their index in the frame
            """
        hash_faces = dict()
        for frame_name, faces in self.data.items():
            for idx, face in enumerate(faces):
                hash_faces.setdefault(face["hash"], dict())[frame_name] = idx
        return hash_faces

    # << INIT FUNCTIONS >> #

    @staticmethod
    def get_serializer(filename, serializer):
        """ Set the serializer to be used for loading and
            saving alignments

            If a filename with a valid extension is passed in
            this will be used as the serializer, otherwise the
            specified serializer will be used """
        logger.debug("Getting serializer: (filename: '%s', serializer: '%s')",
                     filename, serializer)
        extension = os.path.splitext(filename)[1]
        if extension in (".json", ".p", ".yaml", ".yml"):
            logger.debug("Serializer set from file extension: '%s'", extension)
            retval = Serializer.get_serializer_from_ext(extension)
        elif serializer not in ("json", "pickle", "yaml"):
            raise ValueError("Error: {} is not a valid serializer. Use "
                             "'json', 'pickle' or 'yaml'")
        else:
            logger.debug("Serializer set from argument: '%s'", serializer)
            retval = Serializer.get_serializer(serializer)
        logger.verbose("Using '%s' serializer for alignments", retval.ext)
        return retval

    def get_location(self, folder, filename):
        """ Return the path to alignments file """
        logger.debug("Getting location: (folder: '%s', filename: '%s')", folder, filename)
        extension = os.path.splitext(filename)[1]
        if extension in (".json", ".p", ".yaml", ".yml"):
            logger.debug("File extension set from filename: '%s'", extension)
            location = os.path.join(str(folder), filename)
        else:
            location = os.path.join(str(folder),
                                    "{}.{}".format(filename,
                                                   self.serializer.ext))
            logger.debug("File extension set from serializer: '%s'", self.serializer.ext)
        logger.verbose("Alignments filepath: '%s'", location)
        return location

    # << I/O >> #

    def load(self):
        """ Load the alignments data
            Override for custom loading logic """
        logger.debug("Loading alignments")
        if not self.have_alignments_file:
            raise ValueError("Error: Alignments file not found at "
                             "{}".format(self.file))

        try:
            logger.info("Reading alignments from: '%s'", self.file)
            with open(self.file, self.serializer.roptions) as align:
                data = self.serializer.unmarshal(align.read())
        except IOError as err:
            logger.error("'%s' not read: %s", self.file, err.strerror)
            exit(1)
        logger.debug("Loaded alignments")
        return data

    def reload(self):
        """ Read the alignments data from the correct format """
        logger.debug("Re-loading alignments")
        self.data = self.load()
        logger.debug("Re-loaded alignments")

    def save(self):
        """ Write the serialized alignments file """
        logger.debug("Saving alignments")
        try:
            logger.info("Writing alignments to: '%s'", self.file)
            with open(self.file, self.serializer.woptions) as align:
                align.write(self.serializer.marshal(self.data))
            logger.debug("Saved alignments")
        except IOError as err:
            logger.error("'%s' not written: %s", self.file, err.strerror)

    def backup(self):
        """ Backup copy of old alignments """
        logger.debug("Backing up alignments")
        if not os.path.isfile(self.file):
            logger.debug("No alignments to back up")
            return
        now = datetime.now().strftime("%Y%m%d_%H%M%S")
        src = self.file
        split = os.path.splitext(src)
        dst = split[0] + "_" + now + split[1]
        logger.info("Backing up original alignments to '%s'", dst)
        os.rename(src, dst)
        logger.debug("Backed up alignments")

    # << VALIDATION >> #

    def frame_exists(self, frame):
        """ return path of images that have faces """
        retval = frame in self.data.keys()
        logger.trace("'%s': %s", frame, retval)
        return retval

    def frame_has_faces(self, frame):
        """ Return true if frame exists and has faces """
        retval = bool(self.data.get(frame, list()))
        logger.trace("'%s': %s", frame, retval)
        return retval

    def frame_has_multiple_faces(self, frame):
        """ Return true if frame exists and has faces """
        if not frame:
            retval = False
        else:
            retval = bool(len(self.data.get(frame, list())) > 1)
        logger.trace("'%s': %s", frame, retval)
        return retval

    # << DATA >> #

    def get_faces_in_frame(self, frame):
        """ Return the alignments for the selected frame """
        logger.trace("Getting faces for frame: '%s'", frame)
        return self.data.get(frame, list())

    def get_full_frame_name(self, frame):
        """ Return a frame with extension for when the extension is
            not known """
        retval = next(key for key in self.data.keys()
                      if key.startswith(frame))
        logger.trace("Requested: '%s', Returning: '%s'", frame, retval)
        return retval

    def count_faces_in_frame(self, frame):
        """ Return number of alignments within frame """
        retval = len(self.data.get(frame, list()))
        logger.trace(retval)
        return retval

    # << MANIPULATION >> #

    def delete_face_at_index(self, frame, idx):
        """ Delete the face alignment for given frame at given index """
        logger.debug("Deleting face %s for frame '%s'", idx, frame)
        idx = int(idx)
        if idx + 1 > self.count_faces_in_frame(frame):
            logger.debug("No face to delete: (frame: '%s', idx %s)", frame, idx)
            return False
        del self.data[frame][idx]
        logger.debug("Deleted face: (frame: '%s', idx %s)", frame, idx)
        return True

    def add_face(self, frame, alignment):
        """ Add a new face for a frame and return it's index """
        logger.debug("Adding face to frame: '%s'", frame)
        if frame not in self.data:
            self.data[frame] = []
        self.data[frame].append(alignment)
        retval = self.count_faces_in_frame(frame) - 1
        logger.debug("Returning new face index: %s", retval)
        return retval

    def update_face(self, frame, idx, alignment):
        """ Replace a face for given frame and index """
        logger.debug("Updating face %s for frame '%s'", idx, frame)
        self.data[frame][idx] = alignment

    def filter_hashes(self, hashlist, filter_out=False):
        """ Filter in or out faces that match the hashlist

            filter_out=True: Remove faces that match in the hashlist
            filter_out=False: Remove faces that are not in the hashlist
        """
        hashset = set(hashlist)
        for filename, frame in self.data.items():
            for idx, face in reversed(list(enumerate(frame))):
                if ((filter_out and face.get("hash", None) in hashset) or
                        (not filter_out and face.get("hash", None) not in hashset)):
                    logger.verbose("Filtering out face: (filename: %s, index: %s)", filename, idx)
                    del frame[idx]
                else:
                    logger.trace("Not filtering out face: (filename: %s, index: %s)",
                                 filename, idx)

    # << GENERATORS >> #

    def yield_faces(self):
        """ Yield face alignments for one image """
        for frame_fullname, alignments in self.data.items():
            frame_name = os.path.splitext(frame_fullname)[0]
            face_count = len(alignments)
            logger.trace("Yielding: (frame: '%s', faces: %s, frame_fullname: '%s')",
                         frame_name, face_count, frame_fullname)
            yield frame_name, alignments, face_count, frame_fullname

    @staticmethod
    def yield_original_index_reverse(image_alignments, number_alignments):
        """ Return the correct original index for
            alignment in reverse order """
        for idx, _ in enumerate(reversed(image_alignments)):
            original_idx = number_alignments - 1 - idx
            logger.trace("Yielding: face index %s", original_idx)
            yield original_idx

    # << LEGACY FUNCTIONS >> #

    def update_legacy(self):
        """ Update legacy alignments """
        if self.has_legacy_landmarksxy():
            logger.info("Updating legacy alignments")
            self.update_legacy_landmarksxy()
    # < Rotation > #
    # The old rotation method would rotate the image to find a face, then
    # store the rotated landmarks along with a rotation value to tell the
    # convert process that it had to rotate the frame to find the landmarks.
    # This is problematic for numerous reasons. The process now rotates the
    # landmarks to correctly correspond with the original frame. The below are
    # functions to convert legacy alignments to the currently supported
    # infrastructure.
    # This can eventually be removed

    def get_legacy_rotation(self):
        """ Return a list of frames with legacy rotations
            Looks for an 'r' value in the alignments file that
            is not zero """
        logger.debug("Getting alignments containing legacy rotations")
        keys = list()
        for key, val in self.data.items():
            if any(alignment.get("r", None) for alignment in val):
                keys.append(key)
        logger.debug("Got alignments containing legacy rotations: %s", len(keys))
        return keys

    def rotate_existing_landmarks(self, frame_name, frame):
        """ Backwards compatability fix. Rotates the landmarks to
            their correct position and deletes r

            NB: The original frame must be passed in otherwise
            the transformation cannot be performed """
        logger.trace("Rotating existing landmarks for frame: '%s'", frame_name)
        dims = frame.shape[:2]
        for face in self.get_faces_in_frame(frame_name):
            angle = face.get("r", 0)
            if not angle:
                logger.trace("Landmarks do not require rotation: '%s'", frame_name)
                return
            logger.trace("Rotating landmarks: (frame: '%s', angle: %s)", frame_name, angle)
            r_mat = self.get_original_rotation_matrix(dims, angle)
            rotate_landmarks(face, r_mat)
            del face["r"]
        logger.trace("Rotatated existing landmarks for frame: '%s'", frame_name)

    @staticmethod
    def get_original_rotation_matrix(dimensions, angle):
        """ Calculate original rotation matrix and invert """
        logger.trace("Getting original rotation matrix: (dimensions: %s, angle: %s)",
                     dimensions, angle)
        height, width = dimensions
        center = (width/2, height/2)
        r_mat = cv2.getRotationMatrix2D(  # pylint: disable=no-member
            center, -1.0 * angle, 1.)

        abs_cos = abs(r_mat[0, 0])
        abs_sin = abs(r_mat[0, 1])
        rotated_width = int(height*abs_sin + width*abs_cos)
        rotated_height = int(height*abs_cos + width*abs_sin)
        r_mat[0, 2] += rotated_width/2 - center[0]
        r_mat[1, 2] += rotated_height/2 - center[1]
        logger.trace("Returning rotation matrix: %s", r_mat)
        return r_mat

    # <Face Hashes> #
    # The old index based method of face matching is problematic.
    # The SHA1 Hash of the extracted face is now stored in the alignments file.
    # This has it's own issues, but they are far reduced from the index/filename method
    # This can eventually be removed
    def get_legacy_no_hashes(self):
        """ Get alignments without face hashes """
        logger.debug("Getting alignments without face hashes")
        keys = list()
        for key, val in self.data.items():
            for alignment in val:
                if "hash" not in alignment.keys():
                    keys.append(key)
                    break
        logger.debug("Got alignments without face hashes: %s", len(keys))
        return keys

    def add_face_hashes(self, frame_name, hashes):
        """ Backward compatability fix. Add face hash to alignments """
        logger.trace("Adding face hash: (frame: '%s', hashes: %s)", frame_name, hashes)
        faces = self.get_faces_in_frame(frame_name)
        count_match = len(faces) - len(hashes)
        if count_match != 0:
            msg = "more" if count_match > 0 else "fewer"
            logger.warning("There are %s %s face(s) in the alignments file than exist in the "
                           "faces folder. Check your sources for frame '%s'.",
                           abs(count_match), msg, frame_name)
        for idx, i_hash in hashes.items():
            faces[idx]["hash"] = i_hash

    # <landmarks> #
    # Landmarks renamed from landmarksXY to landmarks_xy for PEP compliance
    def has_legacy_landmarksxy(self):
        """ check for legacy landmarksXY keys """
        logger.debug("checking legacy landmarksXY")
        retval = (any(key == "landmarksXY"
                      for alignments in self.data.values()
                      for alignment in alignments
                      for key in alignment))
        logger.debug("legacy landmarksXY: %s", retval)
        return retval

    def update_legacy_landmarksxy(self):
        """ Update landmarksXY to landmarks_xy and save alignments """
        update_count = 0
        for alignments in self.data.values():
            for alignment in alignments:
                alignment["landmarks_xy"] = alignment.pop("landmarksXY")
                update_count += 1
        logger.debug("Updated landmarks_xy: %s", update_count)
        self.save()