# Licensed under GPL3 https://github.com/maoschanz/drawing/blob/master/LICENSE

import cairo, math
from gi.repository import Gdk, GdkPixbuf
from .selection_manager import NoSelectionPathException

################################################################################
# Selection overlay ############################################################

def utilities_show_overlay_on_context(ccontext, cpath, thickness=1):
	"""Draw a blueish area on `ccontext`, for the selection."""
	if cpath is None:
		raise NoSelectionPathException()
	ccontext.new_path()
	ccontext.set_antialias(cairo.Antialias.NONE)
	ccontext.set_line_width(thickness)
	ccontext.set_dash([thickness * 3, thickness * 3])
	ccontext.append_path(cpath)
	ccontext.set_source_rgba(0.1, 0.1, 0.3, 0.2)
	ccontext.fill_preserve()
	ccontext.set_source_rgba(0.5, 0.5, 0.5, 0.5)
	ccontext.stroke()

################################################################################
# Transform tools overlay ######################################################

def utilities_show_handles_on_context(cairo_context, x1, x2, y1, y2, thickness=1):
	"""Request the drawing of handles for a rectangle pixbuf having the provided
	coords. Handles are only decorative objects drawn on the surface to help the
	user understand the rationale of tools without relying on the mouse cursor."""
	radius = _get_radius((x2 - x1), (y2 - y1), thickness)
	lateral_handles = True # may become a parameter later
	if radius < 4 * thickness:
		cairo_context.set_line_width(thickness)
	elif radius < 8 * thickness:
		cairo_context.set_line_width(2 * thickness)
	else:
		cairo_context.set_line_width(3 * thickness)

	_draw_arc_handle(cairo_context, x1, y1, radius, 'nw')
	_draw_arc_handle(cairo_context, x2, y1, radius, 'ne')
	_draw_arc_handle(cairo_context, x2, y2, radius, 'se')
	_draw_arc_handle(cairo_context, x1, y2, radius, 'sw')
	if lateral_handles:
		_draw_arc_handle(cairo_context, (x1+x2)/2, y1, radius, 'n')
		_draw_arc_handle(cairo_context, x2, (y1+y2)/2, radius, 'e')
		_draw_arc_handle(cairo_context, (x1+x2)/2, y2, radius, 's')
		_draw_arc_handle(cairo_context, x1, (y1+y2)/2, radius, 'w')

	cairo_context.move_to(x1, y1)
	cairo_context.line_to(x1, y2)
	cairo_context.line_to(x2, y2)
	cairo_context.line_to(x2, y1)
	cairo_context.close_path()

	cairo_context.set_line_width(thickness)
	cairo_context.set_dash([2 * thickness, 2 * thickness])
	cairo_context.set_source_rgba(0.5, 0.5, 0.5, 0.5)
	cairo_context.stroke()

def _draw_arc_handle(cairo_context, x, y, radius, orientation):
	"""Draw a moon-like shape with the given orientation and radius. The coords
	are the center of the shape. The orientation is an enumeration provided as a
	string with the stupid n/nw/w/sw/s/se/e/ne format."""
	if orientation == 'nw':
		angle_1 = 0.5 * math.pi
		angle_2 = 2.0 * math.pi
	elif orientation == 'n':
		angle_1 = math.pi
		angle_2 = 0.0
	elif orientation == 'ne':
		angle_1 = math.pi
		angle_2 = 0.5 * math.pi
	elif orientation == 'e':
		angle_1 = -0.5 * math.pi
		angle_2 = 0.5 * math.pi
	elif orientation == 'se':
		angle_1 = -0.5 * math.pi
		angle_2 = math.pi
	elif orientation == 's':
		angle_1 = 0.0
		angle_2 = math.pi
	elif orientation == 'sw':
		angle_1 = 0.0
		angle_2 = -0.5 * math.pi
	elif orientation == 'w':
		angle_1 = 0.5 * math.pi
		angle_2 = -0.5 * math.pi

	cairo_context.move_to(x, y)
	cairo_context.arc(x, y, radius, angle_1, angle_2)
	cairo_context.close_path()
	cairo_context.set_source_rgba(1.0, 1.0, 1.0, 1.0)
	cairo_context.fill_preserve()
	cairo_context.set_source_rgba(0.5, 0.5, 0.5, 0.5)
	cairo_context.stroke()

def _get_radius(dx, dy, thickness):
	return min([dx/5, dy/5, 12 * thickness])

################################################################################
# Canvas generic ouline ########################################################

def utilities_generic_canvas_outline(cairo_context, zoom_level, w, h):
	cairo_context.set_source_rgba(0.0, 0.0, 0.0, 1.0)
	cairo_context.set_dash([])
	size = max(1, int(1 / zoom_level))
	cairo_context.set_line_width(size)
	cairo_context.move_to(w + size, 0)
	cairo_context.rel_line_to(0, h + size)
	cairo_context.line_to(0, h + size)
	cairo_context.stroke_preserve()

	cairo_context.set_source_rgba(1.0, 1.0, 1.0, 1.0)
	cairo_context.set_dash([2 * size, 2 * size])
	cairo_context.stroke()

################################################################################