/* This file is part of Korman.
 *
 * Korman 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.
 *
 * Korman 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 Korman.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "texture.h"
#include "buffer.h"

#ifdef _WIN32
#   define WIN32_LEAN_AND_MEAN
#   define NOMINMAX
#   include <windows.h>
#endif // _WIN32

#include <gl/gl.h>
#include <PRP/Surface/plMipmap.h>

#ifndef GL_GENERATE_MIPMAP
#   define GL_GENERATE_MIPMAP 0x8191
#endif // GL_GENERATE_MIPMAP

extern "C" {

typedef struct {
    PyObject_HEAD
    PyObject* m_blenderImage;
    bool m_ownIt;
    GLint m_prevImage;
    bool m_changedState;
    GLint m_mipmapState;
} pyGLTexture;

typedef struct {
    PyObject_HEAD
    plMipmap* fThis;
    bool fPyOwned;
} pyMipmap;

static void pyGLTexture_dealloc(pyGLTexture* self) {
    if (self->m_blenderImage) Py_DECREF(self->m_blenderImage);
    Py_TYPE(self)->tp_free((PyObject*)self);
}

static PyObject* pyGLTexture_new(PyTypeObject* type, PyObject* args, PyObject* kwds) {
    pyGLTexture* self = (pyGLTexture*)type->tp_alloc(type, 0);
    self->m_blenderImage = NULL;
    self->m_ownIt = false;
    self->m_prevImage = 0;
    self->m_changedState = false;
    self->m_mipmapState = 0;
    return (PyObject*)self;
}

static int pyGLTexture___init__(pyGLTexture* self, PyObject* args, PyObject* kwds) {
    PyObject* blender_image;
    if (!PyArg_ParseTuple(args, "O", &blender_image)) {
        PyErr_SetString(PyExc_TypeError, "expected a bpy.types.Image");
        return -1;
    }

    // Save a reference to the Blender image
    Py_INCREF(blender_image);
    self->m_blenderImage = blender_image;

    // Done!
    return 0;
}

static PyObject* pyGLTexture__enter__(pyGLTexture* self) {
    // Is the image already loaded?
    PyObjectRef bindcode = PyObject_GetAttrString(self->m_blenderImage, "bindcode");
    if (!PyLong_Check(bindcode)) {
        PyErr_SetString(PyExc_RuntimeError, "Image bindcode isn't a long?");
        return NULL;
    }

    glGetIntegerv(GL_TEXTURE_BINDING_2D, &self->m_prevImage);
    GLuint image_bindcode = PyLong_AsLong(bindcode);
    self->m_ownIt = image_bindcode == 0;

    // Load image into GL
    if (self->m_ownIt) {
        PyObjectRef new_bind = PyObject_CallMethod(self->m_blenderImage, "gl_load", NULL);
        if (!(PyObject*)new_bind) {
            PyErr_SetString(PyExc_RuntimeError, "failed to load image into GL");
            return NULL;
        }
        image_bindcode = PyLong_AsLong(new_bind);
    }

    // Set image as current in GL
    if (self->m_prevImage != image_bindcode) {
        self->m_changedState = true;
        glBindTexture(GL_TEXTURE_2D, image_bindcode);
    }

    // Misc GL state
    glGetTexParameteriv(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, &self->m_mipmapState);

    Py_INCREF(self);
    return (PyObject*)self;
}

static PyObject* pyGLTexture__exit__(pyGLTexture* self, PyObject*) {
    // We don't care about the args here
    glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, self->m_mipmapState);
    if (self->m_changedState)
        glBindTexture(GL_TEXTURE_2D, self->m_prevImage);
    Py_RETURN_NONE;
}

static PyObject* pyGLTexture_generate_mipmap(pyGLTexture* self) {
    glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, 1);
    Py_RETURN_NONE;
}

static uint8_t* _get_level_data(pyGLTexture* self, GLint level, bool bgra, size_t* size) {
    GLint width, height;
    glGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_WIDTH, &width);
    glGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_HEIGHT, &height);
    GLenum fmt = bgra ? GL_BGRA_EXT : GL_RGBA;

    *size = (width * height * 4);
    uint8_t* buf = new uint8_t[*size];
    glGetTexImage(GL_TEXTURE_2D, level, fmt, GL_UNSIGNED_BYTE, reinterpret_cast<GLvoid*>(buf));
    return buf;
}

static PyObject* pyGLTexture_get_level_data(pyGLTexture* self, PyObject* args, PyObject* kwargs) {
    static char* kwlist[] = { _pycs("level"), _pycs("calc_alpha"), _pycs("bgra"),
                              _pycs("quiet"), NULL };
    GLint level = 0;
    bool calc_alpha = false;
    bool bgra = false;
    bool quiet = false;
    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|ibbb", kwlist, &level, &calc_alpha, &bgra, &quiet)) {
        PyErr_SetString(PyExc_TypeError, "get_level_data expects an optional int, bool, bool, bool");
        return NULL;
    }

    size_t bufsz;
    uint8_t* buf = _get_level_data(self, level, bgra, &bufsz);
    if (calc_alpha) {
        for (size_t i = 0; i < bufsz; i += 4)
            buf[i + 3] = (buf[i + 0] + buf[i + 1] + buf[i + 2]) / 3;
    }

    return pyBuffer_Steal(buf, bufsz);
}

static PyObject* pyGLTexture_store_in_mipmap(pyGLTexture* self, PyObject* args) {
    pyMipmap* pymipmap;
    PyObject* levels;
    size_t compression;
    if (!PyArg_ParseTuple(args, "OOn", &pymipmap, &levels, &compression) || !PySequence_Check(levels)) {
        PyErr_SetString(PyExc_TypeError, "store_in_mipmap expects a plMipmap, sequence of Buffer and int");
        return NULL;
    }

    // Since we actually have no way of knowing if that really is a pyMipmap...
    plMipmap* mipmap = plMipmap::Convert(pymipmap->fThis, false);
    if (!mipmap) {
        PyErr_SetString(PyExc_TypeError, "store_in_mipmap expects a plMipmap, sequence of Buffer and int");
        return NULL;
    }

    for (Py_ssize_t i = 0; i < PySequence_Size(levels); ++i) {
        pyBuffer* item = (pyBuffer*)PySequence_GetItem(levels, i);
        if (!pyBuffer_Check((PyObject*)item)) {
            PyErr_SetString(PyExc_TypeError, "store_in_mipmap expects a plMipmap, sequence of Buffer and int");
            return NULL;
        }

        if (compression == plBitmap::kDirectXCompression)
            mipmap->CompressImage(i, item->m_buffer, item->m_size);
        else
            mipmap->setLevelData(i, item->m_buffer, item->m_size);
    }

    Py_RETURN_NONE;
}

static PyMethodDef pyGLTexture_Methods[] = {
    { _pycs("__enter__"), (PyCFunction)pyGLTexture__enter__, METH_NOARGS, NULL },
    { _pycs("__exit__"), (PyCFunction)pyGLTexture__enter__, METH_VARARGS, NULL },

    { _pycs("generate_mipmap"), (PyCFunction)pyGLTexture_generate_mipmap, METH_NOARGS, NULL },
    { _pycs("get_level_data"), (PyCFunction)pyGLTexture_get_level_data, METH_KEYWORDS | METH_VARARGS, NULL },
    { _pycs("store_in_mipmap"), (PyCFunction)pyGLTexture_store_in_mipmap, METH_VARARGS, NULL },
    { NULL, NULL, 0, NULL }
};

static PyObject* pyGLTexture_get_has_alpha(pyGLTexture* self, void*) {
    size_t bufsz;
    uint8_t* buf = _get_level_data(self, 0, false, &bufsz);
    for (size_t i = 3; i < bufsz; i += 4) {
        if (buf[i] != 255) {
            delete[] buf;
            return PyBool_FromLong(1);
        }
    }
    delete[] buf;
    return PyBool_FromLong(0);
}

static PyGetSetDef pyGLTexture_GetSet[] = {
    { _pycs("has_alpha"), (getter)pyGLTexture_get_has_alpha, NULL, NULL, NULL },
    { NULL, NULL, NULL, NULL, NULL }
};

PyTypeObject pyGLTexture_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "_korlib.GLTexture",                /* tp_name */
    sizeof(pyGLTexture),                /* tp_basicsize */
    0,                                  /* tp_itemsize */

    (destructor)pyGLTexture_dealloc,    /* tp_dealloc */
    NULL,                               /* tp_print */
    NULL,                               /* tp_getattr */
    NULL,                               /* tp_setattr */
    NULL,                               /* tp_compare */
    NULL,                               /* tp_repr */
    NULL,                               /* tp_as_number */
    NULL,                               /* tp_as_sequence */
    NULL,                               /* tp_as_mapping */
    NULL,                               /* tp_hash */
    NULL,                               /* tp_call */
    NULL,                               /* tp_str */
    NULL,                               /* tp_getattro */
    NULL,                               /* tp_setattro */
    NULL,                               /* tp_as_buffer */

    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
    "GLTexture",                              /* tp_doc */

    NULL,                               /* tp_traverse */
    NULL,                               /* tp_clear */
    NULL,                               /* tp_richcompare */
    0,                                  /* tp_weaklistoffset */
    NULL,                               /* tp_iter */
    NULL,                               /* tp_iternext */

    pyGLTexture_Methods,                /* tp_methods */
    NULL,                               /* tp_members */
    pyGLTexture_GetSet,                 /* tp_getset */
    NULL,                               /* tp_base */
    NULL,                               /* tp_dict */
    NULL,                               /* tp_descr_get */
    NULL,                               /* tp_descr_set */
    0,                                  /* tp_dictoffset */

    (initproc)pyGLTexture___init__,     /* tp_init */
    NULL,                               /* tp_alloc */
    pyGLTexture_new,                    /* tp_new */
    NULL,                               /* tp_free */
    NULL,                               /* tp_is_gc */

    NULL,                               /* tp_bases */
    NULL,                               /* tp_mro */
    NULL,                               /* tp_cache */
    NULL,                               /* tp_subclasses */
    NULL,                               /* tp_weaklist */

    NULL,                               /* tp_del */
    0,                                  /* tp_version_tag */
    NULL,                               /* tp_finalize */
};

PyObject* Init_pyGLTexture_Type() {
    if (PyType_Ready(&pyGLTexture_Type) < 0)
        return NULL;

    Py_INCREF(&pyGLTexture_Type);
    return (PyObject*)&pyGLTexture_Type;
}

};