#include "render.h"

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "IL/il.h"
#include "IL/ilu.h"

#include "shared/types.h"
#include "color.h"
#include "system.h"

typedef struct
{
    struct
    {
        unsigned char dirty    : 1;
        unsigned char edge     : 1;
        unsigned char callback : 6;
    } flags;
    union
    {
        Vector3 location;
        struct {
            double r;
            double g;
            double b;
        } color;
    } data;
    double z;
} RenderFragment;

typedef struct
{
    int x;
    int y;
    Vector3 pixel;
    Vector3 location;
    int callback;
} ScanPoint;

typedef struct
{
    f_RenderFragmentCallback function;
    void* data;
} FragmentCallback;

struct RenderArea
{
    RenderParams params;
    int pixel_count;
    RenderFragment* pixels;
    ScanPoint* scanline_up;
    ScanPoint* scanline_down;
    int fragment_callbacks_count;
    FragmentCallback fragment_callbacks[64];
    int scanline_left;
    int scanline_right;
    Color background_color;
    volatile int dirty_left;
    volatile int dirty_right;
    volatile int dirty_up;
    volatile int dirty_down;
    volatile int dirty_count;
    Mutex* lock;
    RenderCallbackStart callback_start;
    RenderCallbackDraw callback_draw;
    RenderCallbackUpdate callback_update;
};

typedef struct {
    int startx;
    int endx;
    int starty;
    int endy;
    int finished;
    int interrupt;
    Thread* thread;
    RenderArea* area;
    Renderer* renderer;
} RenderChunk;

#define RENDER_INVERSE 1

static void _callbackStart(int width, int height, Color background) {}
static void _callbackDraw(int x, int y, Color col) {}
static void _callbackUpdate(double progress) {}

void renderInit()
{
}

void renderQuit()
{
}

RenderArea* renderCreateArea()
{
    RenderArea* result;
    
    result = malloc(sizeof(RenderArea));
    result->params.width = 1;
    result->params.height = 1;
    result->params.antialias = 1;
    result->params.quality = 5;
    result->pixel_count = 1;
    result->pixels = malloc(sizeof(RenderFragment));
    result->fragment_callbacks_count = 0;
    result->scanline_up = malloc(sizeof(ScanPoint));
    result->scanline_down = malloc(sizeof(ScanPoint));
    result->scanline_left = 0;
    result->scanline_right = 0;
    result->background_color = COLOR_TRANSPARENT;
    result->dirty_left = 1;
    result->dirty_right = -1;
    result->dirty_down = 1;
    result->dirty_up = -1;
    result->dirty_count = 0;
    result->lock = mutexCreate();
    result->callback_start = _callbackStart;
    result->callback_draw = _callbackDraw;
    result->callback_update = _callbackUpdate;
    
    return result;
}

void renderDeleteArea(RenderArea* area)
{
    mutexDestroy(area->lock);
    free(area->pixels);
    free(area->scanline_up);
    free(area->scanline_down);
    free(area);
}

void renderSetParams(RenderArea* area, RenderParams params)
{
    int width, height;
    
    width = params.width * params.antialias;
    height = params.height * params.antialias;

    area->params = params;
    area->pixels = realloc(area->pixels, sizeof(RenderFragment) * width * height);
    area->pixel_count = width * height;

    area->scanline_left = 0;
    area->scanline_right = width - 1;
    area->scanline_up = realloc(area->scanline_up, sizeof(ScanPoint) * width);
    area->scanline_down = realloc(area->scanline_down, sizeof(ScanPoint) * width);

    area->dirty_left = width;
    area->dirty_right = -1;
    area->dirty_down = height;
    area->dirty_up = -1;
    area->dirty_count = 0;

    renderClear(area);
}

void renderSetBackgroundColor(RenderArea* area, Color* col)
{
    area->background_color = *col;
}

static void _clearScanLines(RenderArea* area)
{
    int x;
    for (x = area->scanline_left; x <= area->scanline_right; x++)
    {
        area->scanline_up[x].y = -1;
        area->scanline_down[x].y = area->params.height * area->params.antialias;
    }
    area->scanline_left = area->params.width * area->params.antialias;
    area->scanline_right = -1;
}

void renderClear(RenderArea* area)
{
    RenderFragment* pixel;
    int x;
    int y;
    
    area->fragment_callbacks_count = 1;
    area->fragment_callbacks[0].function = NULL;
    area->fragment_callbacks[0].data = NULL;

    for (x = 0; x < area->params.width * area->params.antialias; x++)
    {
        for (y = 0; y < area->params.height * area->params.antialias; y++)
        {
            pixel = area->pixels + (y * area->params.width * area->params.antialias + x);
            pixel->z = -100000000.0;
            pixel->flags.dirty = 0;
            pixel->flags.callback = 0;
            pixel->data.color.r = area->background_color.r;
            pixel->data.color.g = area->background_color.g;
            pixel->data.color.b = area->background_color.b;
        }
    }

    area->scanline_left = 0;
    area->scanline_right = area->params.width * area->params.antialias - 1;
    _clearScanLines(area);

    area->callback_start(area->params.width, area->params.height, area->background_color);

    area->dirty_left = area->params.width * area->params.antialias;
    area->dirty_right = -1;
    area->dirty_down = area->params.height * area->params.antialias;
    area->dirty_up = -1;
    area->dirty_count = 0;
}

static inline void _setDirtyPixel(RenderArea* area, int x, int y)
{
    if (x < area->dirty_left)
    {
        area->dirty_left = x;
    }
    if (x > area->dirty_right)
    {
        area->dirty_right = x;
    }
    if (y < area->dirty_down)
    {
        area->dirty_down = y;
    }
    if (y > area->dirty_up)
    {
        area->dirty_up = y;
    }

    area->dirty_count++;
}

static inline Color _getFinalPixel(RenderArea* area, int x, int y)
{
    Color result, col;
    int sx, sy;
    RenderFragment* pixel_data;
    
    result.r = result.g = result.b = 0.0;
    result.a = 1.0;
    for (sx = 0; sx < area->params.antialias; sx++)
    {
        for (sy = 0; sy < area->params.antialias; sy++)
        {
            pixel_data = area->pixels + (y * area->params.antialias + sy) * area->params.width * area->params.antialias + (x * area->params.antialias + sx);
            if (pixel_data->flags.dirty)
            {
                if (pixel_data->flags.edge)
                {
                    col = COLOR_GREY;
                }
                else
                {
                    col = COLOR_WHITE;
                }
            }
            else
            {
                col.r = pixel_data->data.color.r;
                col.g = pixel_data->data.color.g;
                col.b = pixel_data->data.color.b;
            }
            result.r += col.r / (double)(area->params.antialias * area->params.antialias);
            result.g += col.g / (double)(area->params.antialias * area->params.antialias);
            result.b += col.b / (double)(area->params.antialias * area->params.antialias);
        }
    }
    
    return result;
}

static void _processDirtyPixels(RenderArea* area)
{
    int x, y;
    int down, up, left, right;
    
    down = area->dirty_down / area->params.antialias;
    up = area->dirty_up / area->params.antialias;
    left = area->dirty_left / area->params.antialias;
    right = area->dirty_right / area->params.antialias;

    for (y = down; y <= up; y++)
    {
        for (x = left; x <= right; x++)
        {
            area->callback_draw(x, y, _getFinalPixel(area, x, y));
        }
    }

    area->callback_update(0.0);

    area->dirty_left = area->params.width * area->params.antialias;
    area->dirty_right = -1;
    area->dirty_down = area->params.height * area->params.antialias;
    area->dirty_up = -1;
    area->dirty_count = 0;
}

void renderUpdate(RenderArea* area)
{
    mutexAcquire(area->lock);
    _processDirtyPixels(area);
    mutexRelease(area->lock);
}

static void _setAllDirty(RenderArea* area)
{
    area->dirty_left = 0;
    area->dirty_right = area->params.width * area->params.antialias - 1;
    area->dirty_down = 0;
    area->dirty_up = area->params.height * area->params.antialias - 1;
}

static inline unsigned int _pushCallback(RenderArea* area, FragmentCallback callback)
{
    int i;
    for (i = 0; i < area->fragment_callbacks_count; i++)
    {
        if (area->fragment_callbacks[i].function == callback.function && area->fragment_callbacks[i].data == callback.data)
        {
            return i;
        }
    }
    
    if (area->fragment_callbacks_count >= 64)
    {
        return 0;
    }
    else
    {
        area->fragment_callbacks[area->fragment_callbacks_count].function = callback.function;
        area->fragment_callbacks[area->fragment_callbacks_count].data = callback.data;
        return area->fragment_callbacks_count++;
    }
}

static void _pushFragment(RenderArea* area, int x, int y, double z, int edge, Vector3 location, int callback)
{
    RenderFragment* pixel_data;
    
    if (x >= 0 && x < area->params.width * area->params.antialias && y >= 0 && y < area->params.height * area->params.antialias && z > 1.0)
    {
        pixel_data = area->pixels + (y * area->params.width * area->params.antialias + x);

        if (z > pixel_data->z)
        {
            pixel_data->flags.dirty = (unsigned char)1;
            pixel_data->flags.edge = (unsigned char)edge;
            pixel_data->flags.callback = (unsigned char)callback;
            pixel_data->data.location = location;
            pixel_data->z = z;
            _setDirtyPixel(area, x, y);
        }
    }
}

static void _scanGetDiff(ScanPoint* v1, ScanPoint* v2, ScanPoint* result)
{
    result->pixel.x = v2->pixel.x - v1->pixel.x;
    result->pixel.y = v2->pixel.y - v1->pixel.y;
    result->pixel.z = v2->pixel.z - v1->pixel.z;
    result->location.x = v2->location.x - v1->location.x;
    result->location.y = v2->location.y - v1->location.y;
    result->location.z = v2->location.z - v1->location.z;
    result->callback = v1->callback;
}

static void _scanInterpolate(ScanPoint* v1, ScanPoint* diff, double value, ScanPoint* result)
{
    result->pixel.x = v1->pixel.x + diff->pixel.x * value;
    result->pixel.y = v1->pixel.y + diff->pixel.y * value;
    result->pixel.z = v1->pixel.z + diff->pixel.z * value;
    result->location.x = v1->location.x + diff->location.x * value;
    result->location.y = v1->location.y + diff->location.y * value;
    result->location.z = v1->location.z + diff->location.z * value;
    result->callback = v1->callback;
}

static void _pushScanPoint(RenderArea* area, ScanPoint* point)
{
    point->x = (int)floor(point->pixel.x);
    point->y = (int)floor(point->pixel.y);
    
    if (point->x < 0 || point->x >= area->params.width * area->params.antialias)
    {
        return;
    }

    if (point->x > area->scanline_right)
    {
        area->scanline_right = point->x;
        area->scanline_up[area->scanline_right] = *point;
        area->scanline_down[area->scanline_right] = *point;
        if (point->x < area->scanline_left)
        {
            area->scanline_left = point->x;
        }
    }
    else if (point->x < area->scanline_left)
    {
        area->scanline_left = point->x;
        area->scanline_up[area->scanline_left] = *point;
        area->scanline_down[area->scanline_left] = *point;
    }
    else
    {
        if (point->y > area->scanline_up[point->x].y)
        {
            area->scanline_up[point->x] = *point;
        }
        if (point->y < area->scanline_down[point->x].y)
        {
            area->scanline_down[point->x] = *point;
        }
    }
}

static void _pushScanLineEdge(RenderArea* area, ScanPoint* point1, ScanPoint* point2)
{
    double dx, fx;
    ScanPoint diff, point;
    int startx = lround(point1->pixel.x);
    int endx = lround(point2->pixel.x);
    int curx;

    if (endx < startx)
    {
        _pushScanLineEdge(area, point2, point1);
    }
    else if (endx < 0 || startx >= area->params.width * area->params.antialias)
    {
        return;
    }
    else if (startx == endx)
    {
        _pushScanPoint(area, point1);
        _pushScanPoint(area, point2);
    }
    else
    {
        if (startx < 0)
        {
            startx = 0;
        }
        if (endx >= area->params.width * area->params.antialias)
        {
            endx = area->params.width * area->params.antialias - 1;
        }

        dx = point2->pixel.x - point1->pixel.x;
        _scanGetDiff(point1, point2, &diff);
        for (curx = startx; curx <= endx; curx++)
        {
            fx = (double)curx + 0.5;
            if (fx < point1->pixel.x)
            {
                fx = point1->pixel.x;
            }
            else if (fx > point2->pixel.x)
            {
                fx = point2->pixel.x;
            }
            fx = fx - point1->pixel.x;
            _scanInterpolate(point1, &diff, fx / dx, &point);

            /*point.pixel.x = (double)curx;*/
            
            _pushScanPoint(area, &point);
        }
    }
}

static void _renderScanLines(RenderArea* area)
{
    int x, starty, endy, cury;
    ScanPoint diff;
    double dy, fy;
    ScanPoint up, down, current;

    if (area->scanline_right > 0)
    {
        for (x = area->scanline_left; x <= area->scanline_right; x++)
        {
            up = area->scanline_up[x];
            down = area->scanline_down[x];

            starty = down.y;
            endy = up.y;

            if (endy < 0 || starty >= area->params.height * area->params.antialias)
            {
                continue;
            }

            if (starty < 0)
            {
                starty = 0;
            }
            if (endy >= area->params.height * area->params.antialias)
            {
                endy = area->params.height * area->params.antialias - 1;
            }

            dy = up.pixel.y - down.pixel.y;
            _scanGetDiff(&down, &up, &diff);

            current.x = x;
            for (cury = starty; cury <= endy; cury++)
            {
                fy = (double)cury + 0.5;
                if (fy < down.pixel.y)
                {
                    fy = down.pixel.y;
                }
                else if (fy > up.pixel.y)
                {
                    fy = up.pixel.y;
                }
                fy = fy - down.pixel.y;

                current.y = cury;
                _scanInterpolate(&down, &diff, fy / dy, &current);

                _pushFragment(area, current.x, current.y, current.pixel.z, (cury == starty || cury == endy), current.location, current.callback);
            }
        }
    }
}

void renderPushTriangle(RenderArea* area, Vector3 pixel1, Vector3 pixel2, Vector3 pixel3, Vector3 location1, Vector3 location2, Vector3 location3, f_RenderFragmentCallback callback, void* callback_data)
{
    FragmentCallback fragment_callback = {callback, callback_data};
    ScanPoint point1, point2, point3;
    double limit_width = (double)(area->params.width * area->params.antialias - 1);
    double limit_height = (double)(area->params.height * area->params.antialias - 1);

    /* Filter if outside screen */
    if (pixel1.z < 1.0 || pixel2.z < 1.0 || pixel3.z < 1.0 || (pixel1.x < 0.0 && pixel2.x < 0.0 && pixel3.x < 0.0) || (pixel1.y < 0.0 && pixel2.y < 0.0 && pixel3.y < 0.0) || (pixel1.x > limit_width && pixel2.x > limit_width && pixel3.x > limit_width) || (pixel1.y > limit_height && pixel2.y > limit_height && pixel3.y > limit_height))
    {
        return;
    }
    
    point1.pixel = pixel1;
    point1.location = location1;
    point1.callback = _pushCallback(area, fragment_callback);

    point2.pixel = pixel2;
    point2.location = location2;
    point2.callback = _pushCallback(area, fragment_callback);

    point3.pixel = pixel3;
    point3.location = location3;
    point3.callback = _pushCallback(area, fragment_callback);
    
    _clearScanLines(area);
    
    _pushScanLineEdge(area, &point1, &point2);
    _pushScanLineEdge(area, &point2, &point3);
    _pushScanLineEdge(area, &point3, &point1);
    
    mutexAcquire(area->lock);
    _renderScanLines(area);
    mutexRelease(area->lock);
}

void* _renderPostProcessChunk(void* data)
{
    int x, y;
    RenderFragment* fragment;
    RenderChunk* chunk = (RenderChunk*)data;

#ifdef RENDER_INVERSE
    for (y = chunk->area->params.height * chunk->area->params.antialias - 1 - chunk->starty; y >= chunk->area->params.height * chunk->area->params.antialias - 1 - chunk->endy; y--)
#else
    for (y = chunk->starty; y <= chunk->endy; y++)
#endif
    {
        for (x = chunk->startx; x <= chunk->endx; x++)
        {
            fragment = chunk->area->pixels + (y * chunk->area->params.width * chunk->area->params.antialias + x);
            if (fragment->flags.dirty)
            {
                FragmentCallback callback;
                Color col;
                
                callback = chunk->area->fragment_callbacks[fragment->flags.callback];
                if (callback.function)
                {
                    col = callback.function(chunk->renderer, fragment->data.location, callback.data);
                    colorNormalize(&col);
                }
                else
                {
                    col = COLOR_BLACK;
                }
                
                fragment->data.color.r = col.r;
                fragment->data.color.g = col.g;
                fragment->data.color.b = col.b;

                mutexAcquire(chunk->area->lock);
                fragment->flags.dirty = 0;
                _setDirtyPixel(chunk->area, x, y);
                mutexRelease(chunk->area->lock);
            }
            /* chunk->area->progress_pixels++; */
        }
        if (chunk->interrupt)
        {
            break;
        }
    }

    chunk->finished = 1;
    return NULL;
}

#define MAX_CHUNKS 8
void renderPostProcess(RenderArea* area, Renderer* renderer, int nbchunks)
{
    volatile RenderChunk chunks[MAX_CHUNKS];
    int i;
    int x, y, dx, dy, nx, ny;
    int loops, running;

    if (nbchunks > MAX_CHUNKS)
    {
        nbchunks = MAX_CHUNKS;
    }
    if (nbchunks < 1)
    {
        nbchunks = 1;
    }

    nx = 10;
    ny = 10;
    dx = area->params.width * area->params.antialias / nx;
    dy = area->params.height * area->params.antialias / ny;
    x = 0;
    y = 0;
    /*_progress_pixels = 0;*/

    for (i = 0; i < nbchunks; i++)
    {
        chunks[i].thread = NULL;
        chunks[i].area = area;
        chunks[i].renderer = renderer;
    }

    running = 0;
    loops = 0;
    while ((y < ny && !renderer->render_interrupt) || running > 0)
    {
        timeSleepMs(100);

        for (i = 0; i < nbchunks; i++)
        {
            if (chunks[i].thread)
            {
                if (chunks[i].finished)
                {
                    threadJoin(chunks[i].thread);
                    chunks[i].thread = NULL;
                    running--;
                }
                else if (renderer->render_interrupt)
                {
                    chunks[i].interrupt = 1;
                }
            }

            if (y < ny && !chunks[i].thread && !renderer->render_interrupt)
            {
                chunks[i].finished = 0;
                chunks[i].interrupt = 0;
                chunks[i].startx = x * dx;
                if (x == nx - 1)
                {
                    chunks[i].endx = area->params.width * area->params.antialias - 1;
                }
                else
                {
                    chunks[i].endx = (x + 1) * dx - 1;
                }
                chunks[i].starty = y * dy;
                if (y == ny - 1)
                {
                    chunks[i].endy = area->params.height * area->params.antialias - 1;
                }
                else
                {
                    chunks[i].endy = (y + 1) * dy - 1;
                }

                chunks[i].thread = threadCreate(_renderPostProcessChunk, (void*)(chunks + i));
                running++;

                if (++x >= nx)
                {
                    y++;
                    x = 0;
                }
            }
        }

        if (++loops >= 10)
        {
            mutexAcquire(area->lock);
            /*_progress = (double)_progress_pixels / (double)_pixel_count;*/
            _processDirtyPixels(area);
            mutexRelease(area->lock);

            loops = 0;
        }
    }

    /*_progress = 1.0;*/
    _processDirtyPixels(area);
    area->callback_update(1.0);
}

int renderSaveToFile(RenderArea* area, const char* path)
{
    ILuint image_id;
    ilGenImages(1, &image_id);
    ilBindImage(image_id);
    Color result;
    ILuint x, y;
    ILuint rgba;
    ILuint data[area->params.height * area->params.width];
    ILenum error;
    int error_count;

    for (y = 0; y < area->params.height; y++)
    {
        for (x = 0; x < area->params.width; x++)
        {
            result = _getFinalPixel(area, x, y);
            rgba = colorTo32BitRGBA(&result);
            data[y * area->params.width + x] = rgba;
        }
    }

    ilTexImage((ILuint)area->params.width, (ILuint)area->params.height, 1, 4, IL_RGBA, IL_UNSIGNED_BYTE, data);
    remove(path);
    ilSaveImage(path);

    ilDeleteImages(1, &image_id);

    error_count = 0;
    while ((error=ilGetError()) != IL_NO_ERROR)
    {
        fprintf(stderr, "IL ERROR : %s\n", iluErrorString(error));
        error_count++;
    }
    return !error_count;
}

void renderSetPreviewCallbacks(RenderArea* area, RenderCallbackStart start, RenderCallbackDraw draw, RenderCallbackUpdate update)
{
    area->callback_start = start ? start : _callbackStart;
    area->callback_draw = draw ? draw : _callbackDraw;
    area->callback_update = update ? update : _callbackUpdate;

    area->callback_start(area->params.width, area->params.height, area->background_color);

    _setAllDirty(area);
    _processDirtyPixels(area);

    area->callback_update(0.0);
}