# ***** BEGIN GPL LICENSE BLOCK *****
#
# This program 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 2
# of the License, or (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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# ***** END GPL LICENSE BLOCK *****

def draw_circle_2d(position, color, radius, *, segments=32):
    """
    Draw a circle.

    :arg position: Position where the circle will be drawn.
    :type position: 2D Vector
    :arg color: Color of the circle. To use transparency GL_BLEND has to be enabled.
    :type color: tuple containing RGBA values
    :arg radius: Radius of the circle.
    :type radius: float
    :arg segments: How many segments will be used to draw the circle.
        Higher values give besser results but the drawing will take longer.
    :type segments: int
    """
    from math import sin, cos, pi
    import gpu
    from gpu.types import (
        GPUBatch,
        GPUVertBuf,
        GPUVertFormat,
    )

    if segments <= 0:
        raise ValueError("Amount of segments must be greater than 0.")

    with gpu.matrix.push_pop():
        gpu.matrix.translate(position)
        gpu.matrix.scale_uniform(radius)
        mul = (1.0 / (segments - 1)) * (pi * 2)
        verts = [(sin(i * mul), cos(i * mul)) for i in range(segments)]
        fmt = GPUVertFormat()
        pos_id = fmt.attr_add(id="pos", comp_type='F32', len=2, fetch_mode='FLOAT')
        vbo = GPUVertBuf(len=len(verts), format=fmt)
        vbo.attr_fill(id=pos_id, data=verts)
        batch = GPUBatch(type='LINE_STRIP', buf=vbo)
        shader = gpu.shader.from_builtin('2D_UNIFORM_COLOR')
        batch.program_set(shader)
        shader.uniform_float("color", color)
        batch.draw()


def draw_texture_2d(texture, position, width, height):
    """
    Draw a 2d texture.

    :arg texture: GPUTexture to draw (e.g. gpu.texture.from_image(image) for :class:`bpy.types.Image`).
    :type texture: :class:`gpu.types.GPUTexture`
    :arg position: Position of the lower left corner.
    :type position: 2D Vector
    :arg width: Width of the image when drawn (not necessarily
        the original width of the texture).
    :type width: float
    :arg height: Height of the image when drawn.
    :type height: float
    """
    import gpu
    from . batch import batch_for_shader

    coords = ((0, 0), (1, 0), (1, 1), (0, 1))

    shader = gpu.shader.from_builtin('2D_IMAGE')
    batch = batch_for_shader(
        shader, 'TRI_FAN',
        {"pos": coords, "texCoord": coords},
    )

    with gpu.matrix.push_pop():
        gpu.matrix.translate(position)
        gpu.matrix.scale((width, height))

        shader = gpu.shader.from_builtin('2D_IMAGE')
        shader.bind()

        if isinstance(texture, int):
            # Call the legacy bgl to not break the existing API
            import bgl
            bgl.glActiveTexture(bgl.GL_TEXTURE0)
            bgl.glBindTexture(bgl.GL_TEXTURE_2D, texture)
            shader.uniform_int("image", 0)
        else:
            shader.uniform_sampler("image", texture)

        batch.draw(shader)
