# -*- encoding: utf-8 -*-
##
## Copyright (C) 2011 Thibaut Girka <thib@sitedethib.com>
##
## 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; version 3 only.
##
## 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.
##

from libc.stdlib cimport malloc, free
from libc.string cimport memset
from os.path import join

from pytouhou.lib.opengl cimport \
         (glVertexPointer, glTexCoordPointer, glColorPointer,
          glVertexAttribPointer, glEnableVertexAttribArray, glBlendFunc,
          glBindTexture, glDrawElements, glBindBuffer, glBufferData,
          GL_ARRAY_BUFFER, GL_DYNAMIC_DRAW, GL_UNSIGNED_BYTE,
          GL_UNSIGNED_SHORT, GL_SHORT, GL_FLOAT, GL_SRC_ALPHA,
          GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ZERO, GL_TEXTURE_2D, GL_TRIANGLES,
          glGenBuffers, glBindFramebuffer, glViewport, glDeleteBuffers,
          glGenTextures, glTexParameteri, glTexImage2D, glGenRenderbuffers,
          glBindRenderbuffer, glRenderbufferStorage, glGenFramebuffers,
          glFramebufferTexture2D, glFramebufferRenderbuffer,
          glCheckFramebufferStatus, GL_FRAMEBUFFER, GL_TEXTURE_MIN_FILTER,
          GL_LINEAR, GL_TEXTURE_MAG_FILTER, GL_RGBA, GL_RENDERBUFFER,
          GL_DEPTH_COMPONENT, GL_COLOR_ATTACHMENT0, GL_DEPTH_ATTACHMENT,
          GL_FRAMEBUFFER_COMPLETE, glClear, GL_COLOR_BUFFER_BIT,
          GL_DEPTH_BUFFER_BIT, GLuint, glDeleteTextures)

from pytouhou.lib.sdl import SDLError

from pytouhou.game.element cimport Element
from .sprite cimport get_sprite_rendering_data

from pytouhou.utils.helpers import get_logger

logger = get_logger(__name__)


cdef class Texture:
    def __cinit__(self, GLuint texture, Renderer renderer):
        self.texture = texture

        # Find an unused key in the textures array.
        for key in xrange(MAX_TEXTURES):
            if renderer.textures[key] == 0:
                break
        else:
            raise MemoryError('Too many textures currently loaded, consider increasing MAX_TEXTURES (currently %d).' % MAX_TEXTURES)

        self.key = key
        self.pointer = &renderer.textures[key]
        self.pointer[0] = texture
        for i in xrange(2):
            renderer.indices[key][i] = self.indices[i]

    def __dealloc__(self):
        if self.texture:
            glDeleteTextures(1, &self.texture)
        if self.pointer != NULL:
            self.pointer[0] = 0
        # The dangling pointers in renderer.indices doesn’t matter, since we
        # won’t use them if no texture is loaded in that slot.


cdef long find_objects(Renderer self, object elements) except -1:
    # Don’t type element as Element, or else the overriding of objects won’t work.
    cdef Element obj
    cdef long i = 0
    for element in elements:
        for obj in element.objects:
            sprite = obj.sprite
            if sprite and sprite.visible:
                # warning: no reference is preserved on the object—assuming the object will not die accidentally
                self.elements[i] = <PyObject*>obj
                i += 1
                if i >= 640*3-4:
                    return i
    return i


cdef class Renderer:
    def __dealloc__(self):
        if not self.use_fixed_pipeline:
            glDeleteBuffers(1, &self.framebuffer_vbo)
            glDeleteBuffers(1, &self.vbo)


    def __init__(self, resource_loader):
        self.texture_manager = TextureManager(resource_loader, self, Texture)
        font_name = join(resource_loader.game_dir, 'font.ttf')
        try:
            self.font_manager = FontManager(font_name, 16, self, Texture)
        except SDLError:
            self.font_manager = None
            logger.error('Font file “%s” not found, disabling text rendering altogether.', font_name)

        if not self.use_fixed_pipeline:
            glGenBuffers(1, &self.vbo)
            glGenBuffers(1, &self.framebuffer_vbo)


    cdef void render_elements(self, elements):
        cdef int key
        cdef short x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4, ox, oy
        cdef float left, right, bottom, top
        cdef unsigned char r, g, b, a

        nb_elements = find_objects(self, elements)
        if not nb_elements:
            return

        nb_vertices = 0
        memset(self.last_indices, 0, sizeof(self.last_indices))

        for element_idx in xrange(nb_elements):
            element = <object>self.elements[element_idx]
            sprite = element.sprite
            ox, oy = element.x, element.y
            key, (vertices, uvs, colors) = get_sprite_rendering_data(sprite)

            blendfunc = key & 1
            texture = key >> 1

            rec = self.indices[texture][blendfunc]
            next_indice = self.last_indices[key]

            # Pack data in buffer
            x1, x2, x3, x4, y1, y2, y3, y4, z1, z2, z3, z4 = vertices
            left, right, bottom, top = uvs
            r, g, b, a = colors
            self.vertex_buffer[nb_vertices] = Vertex(x1 + ox, y1 + oy, z1, 0, left, bottom, r, g, b, a)
            self.vertex_buffer[nb_vertices+1] = Vertex(x2 + ox, y2 + oy, z2, 0, right, bottom, r, g, b, a)
            self.vertex_buffer[nb_vertices+2] = Vertex(x3 + ox, y3 + oy, z3, 0, right, top, r, g, b, a)
            self.vertex_buffer[nb_vertices+3] = Vertex(x4 + ox, y4 + oy, z4, 0, left, top, r, g, b, a)

            # Add indices
            rec[next_indice] = nb_vertices
            rec[next_indice+1] = nb_vertices + 1
            rec[next_indice+2] = nb_vertices + 2
            rec[next_indice+3] = nb_vertices + 2
            rec[next_indice+4] = nb_vertices + 3
            rec[next_indice+5] = nb_vertices
            self.last_indices[key] += 6

            nb_vertices += 4

        if self.use_fixed_pipeline:
            glVertexPointer(3, GL_SHORT, sizeof(Vertex), &self.vertex_buffer[0].x)
            glTexCoordPointer(2, GL_FLOAT, sizeof(Vertex), &self.vertex_buffer[0].u)
            glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(Vertex), &self.vertex_buffer[0].r)
        else:
            glBindBuffer(GL_ARRAY_BUFFER, self.vbo)
            glBufferData(GL_ARRAY_BUFFER, nb_vertices * sizeof(Vertex), &self.vertex_buffer[0], GL_DYNAMIC_DRAW)

            #TODO: find a way to use offsetof() instead of those ugly hardcoded values.
            glVertexAttribPointer(0, 3, GL_SHORT, False, sizeof(Vertex), <void*>0)
            glEnableVertexAttribArray(0)
            glVertexAttribPointer(1, 2, GL_FLOAT, False, sizeof(Vertex), <void*>8)
            glEnableVertexAttribArray(1)
            glVertexAttribPointer(2, 4, GL_UNSIGNED_BYTE, True, sizeof(Vertex), <void*>16)
            glEnableVertexAttribArray(2)

        # Don’t change the state when it’s not needed.
        previous_blendfunc = -1
        previous_texture = -1

        for key in xrange(2 * MAX_TEXTURES):
            nb_indices = self.last_indices[key]
            if not nb_indices:
                continue

            blendfunc = key & 1
            texture = key >> 1

            if blendfunc != previous_blendfunc:
                glBlendFunc(GL_SRC_ALPHA, (GL_ONE_MINUS_SRC_ALPHA, GL_ONE)[blendfunc])
            if texture != previous_texture:
                glBindTexture(GL_TEXTURE_2D, self.textures[texture])
            glDrawElements(GL_TRIANGLES, nb_indices, GL_UNSIGNED_SHORT, self.indices[texture][blendfunc])

            previous_blendfunc = blendfunc
            previous_texture = texture

        glBindTexture(GL_TEXTURE_2D, 0)

        if not self.use_fixed_pipeline:
            glBindBuffer(GL_ARRAY_BUFFER, 0)


    cdef void render_quads(self, rects, colors, GLuint texture):
        # There is nothing that batch more than two quads on the same texture, currently.
        cdef Vertex buf[8]
        cdef unsigned short indices[12]
        indices[:] = [0, 1, 2, 2, 3, 0, 4, 5, 6, 6, 7, 4]

        length = len(rects)
        assert length == len(colors)

        for i, r in enumerate(rects):
            c1, c2, c3, c4 = colors[i]

            buf[4*i] = Vertex(r.x, r.y, 0, 0, 0, 0, c1.r, c1.g, c1.b, c1.a)
            buf[4*i+1] = Vertex(r.x + r.w, r.y, 0, 0, 1, 0, c2.r, c2.g, c2.b, c2.a)
            buf[4*i+2] = Vertex(r.x + r.w, r.y + r.h, 0, 0, 1, 1, c3.r, c3.g, c3.b, c3.a)
            buf[4*i+3] = Vertex(r.x, r.y + r.h, 0, 0, 0, 1, c4.r, c4.g, c4.b, c4.a)

        if self.use_fixed_pipeline:
            glVertexPointer(3, GL_SHORT, sizeof(Vertex), &buf[0].x)
            glTexCoordPointer(2, GL_FLOAT, sizeof(Vertex), &buf[0].u)
            glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(Vertex), &buf[0].r)
        else:
            glBindBuffer(GL_ARRAY_BUFFER, self.vbo)
            glBufferData(GL_ARRAY_BUFFER, 4 * length * sizeof(Vertex), buf, GL_DYNAMIC_DRAW)

            #TODO: find a way to use offsetof() instead of those ugly hardcoded values.
            glVertexAttribPointer(0, 3, GL_SHORT, False, sizeof(Vertex), <void*>0)
            glEnableVertexAttribArray(0)
            glVertexAttribPointer(1, 2, GL_FLOAT, False, sizeof(Vertex), <void*>8)
            glEnableVertexAttribArray(1)
            glVertexAttribPointer(2, 4, GL_UNSIGNED_BYTE, True, sizeof(Vertex), <void*>16)
            glEnableVertexAttribArray(2)

        glBindTexture(GL_TEXTURE_2D, texture)
        glDrawElements(GL_TRIANGLES, 6 * length, GL_UNSIGNED_SHORT, indices)

        if not self.use_fixed_pipeline:
            glBindBuffer(GL_ARRAY_BUFFER, 0)


    cdef void render_framebuffer(self, Framebuffer fb):
        cdef PassthroughVertex[4] buf
        cdef unsigned short indices[6]
        indices[:] = [0, 1, 2, 2, 3, 0]

        assert not self.use_fixed_pipeline

        glBindFramebuffer(GL_FRAMEBUFFER, 0)
        glViewport(self.x, self.y, self.width, self.height)
        glBlendFunc(GL_ONE, GL_ZERO)
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

        glBindBuffer(GL_ARRAY_BUFFER, self.framebuffer_vbo)

        #TODO: find a way to use offsetof() instead of those ugly hardcoded values.
        glVertexAttribPointer(0, 2, GL_SHORT, False, sizeof(PassthroughVertex), <void*>0)
        glEnableVertexAttribArray(0)
        glVertexAttribPointer(1, 2, GL_FLOAT, False, sizeof(PassthroughVertex), <void*>4)
        glEnableVertexAttribArray(1)

        buf[0] = PassthroughVertex(fb.x, fb.y, 0, 1)
        buf[1] = PassthroughVertex(fb.x + fb.width, fb.y, 1, 1)
        buf[2] = PassthroughVertex(fb.x + fb.width, fb.y + fb.height, 1, 0)
        buf[3] = PassthroughVertex(fb.x, fb.y + fb.height, 0, 0)
        glBufferData(GL_ARRAY_BUFFER, 4 * sizeof(PassthroughVertex), buf, GL_DYNAMIC_DRAW)

        glBindTexture(GL_TEXTURE_2D, fb.texture)
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices)
        glBindTexture(GL_TEXTURE_2D, 0)

        glBindBuffer(GL_ARRAY_BUFFER, 0)


cdef class Framebuffer:
    def __init__(self, int x, int y, int width, int height):
        self.x = x
        self.y = y
        self.width = width
        self.height = height

        glGenTextures(1, &self.texture)
        glBindTexture(GL_TEXTURE_2D, self.texture)
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
        glTexImage2D(GL_TEXTURE_2D, 0,
                     GL_RGBA,
                     width, height,
                     0,
                     GL_RGBA, GL_UNSIGNED_BYTE,
                     NULL)
        glBindTexture(GL_TEXTURE_2D, 0)

        glGenRenderbuffers(1, &self.rbo)
        glBindRenderbuffer(GL_RENDERBUFFER, self.rbo)
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, width, height)
        glBindRenderbuffer(GL_RENDERBUFFER, 0)

        glGenFramebuffers(1, &self.fbo)
        glBindFramebuffer(GL_FRAMEBUFFER, self.fbo)
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, self.texture, 0)
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, self.rbo)
        assert glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE
        glBindFramebuffer(GL_FRAMEBUFFER, 0)

    cpdef bind(self):
        glBindFramebuffer(GL_FRAMEBUFFER, self.fbo)