# -*- coding: utf-8 -*-
"""
$Id$

Copyright 2010 Lars Kruse <devel@sumpfralle.de>
Copyright 2008 Lode Leroy

This file is part of PyCAM.

PyCAM is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

PyCAM is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with PyCAM.  If not, see <http://www.gnu.org/licenses/>.
"""

__all__ = ["DropCutter", "PushCutter", "EngraveCutter", "ContourFollow"]

from pycam.Geometry.utils import INFINITE, epsilon, sqrt
from pycam.Geometry.Point import Point
import pycam.Utils.threading


class Hit:
    def __init__(self, cl, cp, t, d, direction):
        self.cl = cl
        self.cp = cp
        self.t = t
        self.d = d
        self.dir = direction
        self.z = -INFINITE

    def __repr__(self):
        return "%s - %s - %s - %s" % (self.d, self.cl, self.dir, self.cp)


def get_free_paths_triangles(models, cutter, p1, p2, return_triangles=False):
    if len(models) == 1:
        # only one model is left - just continue
        model = models[0]
    else:
        # multiple models were given - process them in layers
        result = get_free_paths_triangles(models[:1], cutter, p1, p2,
                return_triangles)
        # group the result into pairs of two points (start/end)
        point_pairs = []
        while result:
            pair1 = result.pop(0)
            pair2 = result.pop(0)
            point_pairs.append((pair1, pair2))
        all_results = []
        for pair in point_pairs:
            one_result = get_free_paths_triangles(models[1:], cutter, pair[0],
                    pair[1], return_triangles)
            all_results.extend(one_result)
        return all_results

    backward = p1.sub(p2).normalized()
    forward = p2.sub(p1).normalized()
    xyz_dist = p2.sub(p1).norm

    minx = min(p1.x, p2.x)
    maxx = max(p1.x, p2.x)
    miny = min(p1.y, p2.y)
    maxy = max(p1.y, p2.y)
    minz = min(p1.z, p2.z)

    # find all hits along scan line
    hits = []

    triangles = model.triangles(minx - cutter.distance_radius,
            miny - cutter.distance_radius, minz, maxx + cutter.distance_radius,
            maxy + cutter.distance_radius, INFINITE)

    for t in triangles:
        (cl1, d1, cp1) = cutter.intersect(backward, t, start=p1)
        if cl1:
            hits.append(Hit(cl1, cp1, t, -d1, backward))
        (cl2, d2, cp2) = cutter.intersect(forward, t, start=p1)
        if cl2:
            hits.append(Hit(cl2, cp2, t, d2, forward))

    # sort along the scan direction
    hits.sort(key=lambda h: h.d)

    count = 0
    points = []
    for h in hits:
        if h.dir == forward:
            if count == 0:
                if -epsilon <= h.d <= xyz_dist + epsilon:
                    if len(points) == 0:
                        points.append((p1, None, None))
                    points.append((h.cl, h.t, h.cp))
            count += 1
        else:
            if count == 1:
                if -epsilon <= h.d <= xyz_dist + epsilon:
                    points.append((h.cl, h.t, h.cp))
            count -= 1

    if len(points) % 2 == 1:
        points.append((p2, None, None))

    if len(points) == 0:
        # check if the path is completely free or if we are inside of the model
        inside_counter = 0
        for h in hits:
            if -epsilon <= h.d:
                # we reached the outer limit of the model
                break
            if h.dir == forward:
                inside_counter += 1
            else:
                inside_counter -= 1
        if inside_counter <= 0:
            # we are not inside of the model
            points.append((p1, None, None))
            points.append((p2, None, None))

    if return_triangles:
        return points
    else:
        # return only the cutter locations (without triangles)
        return [cl for (cl, t, cp) in points]


def get_free_paths_ode(physics, p1, p2, depth=8):
    """ Recursive function for splitting a line (usually along x or y) into
    small pieces to gather connected paths for the PushCutter.
    Strategy: check if the whole line is free (without collisions). Do a
    recursive call (for the first and second half), if there was a
    collision.

    Usually either minx/maxx or miny/maxy should be equal, unless you want
    to do a diagonal cut.
    @param minx: lower limit of x
    @type minx: float
    @param maxx: upper limit of x; should equal minx for a cut along the x axis
    @type maxx: float
    @param miny: lower limit of y
    @type miny: float
    @param maxy: upper limit of y; should equal miny for a cut along the y axis
    @type maxy: float
    @param z: the fixed z level
    @type z: float
    @param depth: number of splits to be calculated via recursive calls; the
        accuracy can be calculated as (maxx-minx)/(2^depth)
    @type depth: int
    @returns: a list of points that describe the tool path of the PushCutter;
        each pair of points defines a collision-free path
    @rtype: list(pycam.Geometry.Point.Point)
    """
    points = []
    # "resize" the drill along the while x/y range and check for a collision
    physics.extend_drill(p2.x - p1.x, p2.y - p1.y, p2.z - p1.z)
    physics.set_drill_position((p1.x, p1.y, p1.z))
    if physics.check_collision():
        # collision detected
        if depth > 0:
            middle_x = (p1.x + p2.x) / 2
            middle_y = (p1.y + p2.y) / 2
            middle_z = (p1.z + p2.z) / 2
            p_middle = Point(middle_x, middle_y, middle_z)
            group1 = get_free_paths_ode(physics, p1, p_middle, depth - 1)
            group2 = get_free_paths_ode(physics, p_middle, p2, depth - 1)
            if group1 and group2 and (group1[-1] == group2[0]):
                # The last pair of the first group ends where the first pair of
                # the second group starts.
                # We will combine them into a single pair.
                points.extend(group1[:-1])
                points.extend(group2[1:])
            else:
                # the two groups are not connected - just add both
                points.extend(group1)
                points.extend(group2)
        else:
            # no points to be added
            pass
    else:
        # no collision - the line is free
        points.append(p1)
        points.append(p2)
    physics.reset_drill()
    return points

def get_max_height_ode(physics, x, y, minz, maxz):
    low, high = minz, maxz
    trip_start = 20
    safe_z = None
    # check if the full step-down would be ok
    physics.set_drill_position((x, y, minz))
    if physics.check_collision():
        # there is an object between z1 and z0 - we need more=None loops
        trips = trip_start
    else:
        # No need for further collision detection - we can go down the whole
        # range z1..z0.
        trips = 0
        safe_z = minz
    while trips > 0:
        current_z = (low + high) / 2
        physics.set_drill_position((x, y, current_z))
        if physics.check_collision():
            low = current_z
        else:
            high = current_z
            safe_z = current_z
        trips -= 1
    if safe_z is None:
        # skip this point (by going up to safety height)
        return None
    else:
        return Point(x, y, safe_z)

def get_max_height_triangles(model, cutter, x, y, minz, maxz):
    p = Point(x, y, maxz)
    height_max = None
    box_x_min = cutter.get_minx(p)
    box_x_max = cutter.get_maxx(p)
    box_y_min = cutter.get_miny(p)
    box_y_max = cutter.get_maxy(p)
    box_z_min = minz
    box_z_max = maxz
    triangles = model.triangles(box_x_min, box_y_min, box_z_min, box_x_max,
            box_y_max, box_z_max)
    for t in triangles:
        cut = cutter.drop(t, start=p)
        if cut and ((height_max is None) or (cut.z > height_max)):
            height_max = cut.z
    # don't do a complete boundary check for the height
    # this avoids zero-cuts for models that exceed the bounding box height
    if (height_max is None) or (height_max < minz + epsilon):
        height_max = minz
    if height_max > maxz:
        return None
    else:
        return Point(x, y, height_max)

def _check_deviance_of_adjacent_points(p1, p2, p3, min_distance):
    straight = p3.sub(p1)
    added = p2.sub(p1).norm + p3.sub(p2).norm
    # compare only the x/y distance of p1 and p3 with min_distance
    if straight.x ** 2 + straight.y ** 2 < min_distance ** 2:
        # the points are too close together
        return True
    else:
        # allow 0.1% deviance - this is an angle of around 2 degrees
        return (added / straight.norm) < 1.001

def get_max_height_dynamic(model, cutter, positions, minz, maxz, physics=None):
    max_depth = 8
    # the points don't need to get closer than 1/1000 of the cutter radius
    min_distance = cutter.distance_radius / 1000
    result = []
    if physics:
        get_max_height = lambda x, y: get_max_height_ode(physics, x, y, minz,
                maxz)
    else:
        get_max_height = lambda x, y: get_max_height_triangles(model, cutter,
                x, y, minz, maxz)
    # add one point between all existing points
    for index in range(len(positions)):
        p = positions[index]
        result.append(get_max_height(p[0], p[1]))
    # Check if three consecutive points are "flat".
    # Add additional points if necessary.
    index = 0
    depth_count = 0
    while index < len(result) - 2:
        p1 = result[index]
        p2 = result[index + 1]
        p3 = result[index + 2]
        if (not p1 is None) and (not p2 is None) and (not p3 is None) \
                and not _check_deviance_of_adjacent_points(p1, p2, p3, min_distance) \
                and (depth_count < max_depth):
            # distribute the new point two before the middle and one after
            if depth_count % 3 != 2:
                # insert between the 1st and 2nd point
                middle = ((p1.x + p2.x) / 2, (p1.y + p2.y) / 2)
                result.insert(index + 1, get_max_height(middle[0], middle[1]))
            else:
                # insert between the 2nd and 3rd point
                middle = ((p2.x + p3.x) / 2, (p2.y + p3.y) / 2)
                result.insert(index + 2, get_max_height(middle[0], middle[1]))
            depth_count += 1
        else:
            index += 1
            depth_count = 0
    return result

