# -*- coding: utf-8 -*-
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.

from __future__ import division

import numpy as np

from .perspective import Base3DRotationCamera


class TurntableCamera(Base3DRotationCamera):
    """ 3D camera class that orbits around a center point while
    maintaining a view on a center point.

    For this camera, the ``scale_factor`` indicates the zoom level, and
    the ``center`` indicates the position to put at the center of the
    view.

    Parameters
    ----------
    fov : float
        Field of view. Zero (default) means orthographic projection.
    elevation : float
        Elevation angle in degrees. Positive angles place the camera
        above the cente point, negative angles place the camera below
        the center point.
    azimuth : float
        Azimuth angle in degrees. Zero degrees places the camera on the
        positive x-axis, pointing in the negative x direction.
    roll : float
        Roll angle in degrees
    distance : float | None
        The distance of the camera from the rotation point (only makes sense
        if fov > 0). If None (default) the distance is determined from the
        scale_factor and fov.
    translate_speed : float
        Scale factor on translation speed when moving the camera center point.
    **kwargs : dict
        Keyword arguments to pass to `BaseCamera`.

    Notes
    -----
    Interaction:

        * LMB: orbits the view around its center point.
        * RMB or scroll: change scale_factor (i.e. zoom level)
        * SHIFT + LMB: translate the center point
        * SHIFT + RMB: change FOV

    """

    _state_props = Base3DRotationCamera._state_props + ('elevation',
                                                        'azimuth', 'roll')

    def __init__(self, fov=45.0, elevation=30.0, azimuth=30.0, roll=0.0,
                 distance=None, translate_speed=1.0, **kwargs):
        super(TurntableCamera, self).__init__(fov=fov, **kwargs)

        # Set camera attributes
        self.azimuth = azimuth
        self.elevation = elevation
        self.roll = roll  # interaction not implemented yet
        self.distance = distance  # None means auto-distance
        self.translate_speed = translate_speed

    @property
    def elevation(self):
        """ The angle of the camera in degrees above the horizontal (x, z)
        plane.
        """
        return self._elevation

    @elevation.setter
    def elevation(self, elev):
        elev = float(elev)
        self._elevation = min(90, max(-90, elev))
        self.view_changed()

    @property
    def azimuth(self):
        """ The angle of the camera in degrees around the y axis. An angle of
        0 places the camera within the (y, z) plane.
        """
        return self._azimuth

    @azimuth.setter
    def azimuth(self, azim):
        azim = float(azim)
        while azim < -180:
            azim += 360
        while azim > 180:
            azim -= 360
        self._azimuth = azim
        self.view_changed()

    @property
    def roll(self):
        """ The angle of the camera in degrees around the z axis. An angle of
        0 places puts the camera upright.
        """
        return self._roll

    @roll.setter
    def roll(self, roll):
        roll = float(roll)
        while roll < -180:
            roll += 360
        while roll > 180:
            roll -= 360
        self._roll = roll
        self.view_changed()

    def orbit(self, azim, elev):
        """ Orbits the camera around the center position.

        Parameters
        ----------
        azim : float
            Angle in degrees to rotate horizontally around the center point.
        elev : float
            Angle in degrees to rotate vertically around the center point.
        """
        self.azimuth += azim
        self.elevation = np.clip(self.elevation + elev, -90, 90)
        self.view_changed()

    def _update_rotation(self, event):
        """Update rotation parmeters based on mouse movement"""
        p1 = event.mouse_event.press_event.pos
        p2 = event.mouse_event.pos
        if self._event_value is None:
            self._event_value = self.azimuth, self.elevation
        self.azimuth = self._event_value[0] - (p2 - p1)[0] * 0.5
        self.elevation = self._event_value[1] + (p2 - p1)[1] * 0.5

    def _rotate_tr(self):
        """Rotate the transformation matrix based on camera parameters"""
        up, forward, right = self._get_dim_vectors()
        self.transform.rotate(self.elevation, -right)
        self.transform.rotate(self.azimuth, up)

    def _dist_to_trans(self, dist):
        """Convert mouse x, y movement into x, y, z translations"""
        rae = np.array([self.roll, self.azimuth, self.elevation]) * np.pi / 180
        sro, saz, sel = np.sin(rae)
        cro, caz, cel = np.cos(rae)
        d0, d1 = dist[0], dist[1]
        dx = (+ d0 * (cro * caz + sro * sel * saz)
              + d1 * (sro * caz - cro * sel * saz)) * self.translate_speed
        dy = (+ d0 * (cro * saz - sro * sel * caz)
              + d1 * (sro * saz + cro * sel * caz)) * self.translate_speed
        dz = (- d0 * sro * cel + d1 * cro * cel) * self.translate_speed
        return dx, dy, dz