#include <stdlib.h>
#include <string.h>
#include "DrawSpan.h"
#include "polygon_pack.h"
#include "SpanPack.h"
#include "texture.h"
#include "viewer_types.h"
#include "TileHash.h"

#define SPAN_PACK_LOAD 0
#define TEX_LOAD 1

SchedDefineTask(DrawSpan);

static TileHashPtr hash;
static TileListPtr tileList;

/**
 * テクスチャは、TEXTURE_SPLIT_PIXEL^2 のブロックに分割する
 *
 * +---+---+---+---+---+---+
 * | 0 | 1 | 2 | 3 | 4 | 5 |
 * +---+---+---+---+---+---+
 * |   |   |   |   |   |11 |
 * +---+---+---+---+---+---+
 * |   |   |   |   |   |17 |
 * +---+---+---+---+---+---+
 * |   |   |   |   |   |23 |
 * +---+---+---+---+---+---+
 * |   |   |   |   |   |29 |
 * +---+---+---+---+---+---+
 * |   |   |   |   |   |35 |
 * +---+---+---+---+---+---+
 *
 * 一辺を TEXTURE_SPLIT とする
 * 各ブロックの数字がブロックIDとなる。
 */

/**
 * テクスチャの座標から、
 * テクスチャのどのブロックかを求める
 *
 * @param[in] tx X coordinates of texture
 * @param[in] tx Y coordinates of texture
 * @param[in] twidth  Width of texture
 * @return block ID
 */
static inline int
get_tex_block(int tx, int ty, int twidth)
{
     int blockX, blockY;

     blockX = tx / TEXTURE_SPLIT_PIXEL;
     blockY = ty / TEXTURE_SPLIT_PIXEL;

     return blockX + (twidth/TEXTURE_SPLIT_PIXEL)*blockY;
}

/**
 * block ID と、テクスチャの TOP address から
 * (tx,ty) で使われるテクスチャの Tile addres を求める
 *
 * @param[in] tx X coordinates of texture
 * @param[in] tx Y coordinates of texture
 * @param[in] tw Width of texture
 * @param[in] tex_addr_top (tx,ty) で使うテクスチャの先頭address
 * @return block ID
 */
static inline uint32*
getTile(int tx, int ty, int tw, uint32 *tex_addr_top)
{
    int block = get_tex_block(tx, ty, tw);
    return tex_addr_top + block*TEXTURE_BLOCK_SIZE;
}

void
DrawSpan::linebuf_init(int *buf, int x, int rgb)
{
    for (int i = 0; i < x; i++) {
	buf[i] = rgb;
    }
}

float*
DrawSpan::zRow_init(int w, int h)
{
    float *zRow = NULL;
    float z = 65535.0f;
    int length = w*h;

    zRow = (float*)smanager->allocate(sizeof(float)*length);

    for (int i = 0; i < length; i++) {
	zRow[i] = z;
    }

    return zRow;
}

Uint32
DrawSpan::get_rgb(int tx, int ty, uint32 *addr)
{
    Uint8 red, green, blue, alpha;
    TilePtr tile;

    tile = hash->get(addr);
    if (tile == NULL) {
	if (tileList->size >= MAX_TILE) {
	    tileList->init();
	    hash->clear();
	}

	tile = &tileList->tile[tileList->size];
	tile->texture_addr = addr;

	smanager->dma_load(tile->pixel, (uint32)addr,
			   sizeof(uint32)*TEXTURE_BLOCK_SIZE, TEX_LOAD);

	int index = hash->put(tile->texture_addr, tile);

	/**
	 * TODO:
	 *   入らなかったやつは
	 *   今までのやつを描画してから続きをするとか
	 */
	if (index < 0) {
	    printf("[%p] Can't entry\n", tile);
	    return 0xff0000;
	}

	tileList->size++;

	smanager->dma_wait(TEX_LOAD);
    }

    return tile->pixel[(TEXTURE_SPLIT_PIXEL)*ty+tx];
}



int
DrawSpan::run(void *rbuf, void *wbuf)
{
    SpanPack *sp = (SpanPack*)smanager->get_input(0);
    SpanPack *next_sp =
	(SpanPack*)smanager->allocate(sizeof(SpanPack));
    SpanPack *free_sp = next_sp; // next_sp の free() 用
    SpanPack *tmp_sp = NULL;
    Span *span;

    hash = (TileHashPtr)smanager->global_get(GLOBAL_TEXTURE_HASH);
    tileList = (TileListPtr)smanager->global_get(GLOBAL_TILE_LIST);

    int rangex_start  = get_param(0); // このタスクが担当する x の範囲の始点
    int rangex_end    = get_param(1); // 終点 (start <= x <= end)
    int rangey        = get_param(2); // y の範囲 (render_y + rangey - 1)
    int rangex        = rangex_end - rangex_start + 1;

    float *zRow = zRow_init(rangex, rangey);
    int **linebuf = (int**)smanager->allocate(sizeof(int*)*rangey);

    for (int i = 0; i < rangey; i++) {
	linebuf[i] = (int*)smanager->get_output(i);
	linebuf_init(linebuf[i], rangex, 0xffffffff);
    }

    do {
	/**
	 * SpanPack->next が存在する場合、
	 * 現在の SpanPack を処理してる間に
	 * 次の SpanPack の DMA 転送を行う
	 */
	if (sp->next != NULL) {
	    smanager->dma_load(next_sp, (uint32)sp->next,
			       sizeof(SpanPack), SPAN_PACK_LOAD);
	} else {
	    next_sp = NULL;
	}

	for (int t = 0; t < sp->info.size; t++) {	  
	    span = &sp->span[t];

	    Uint32 rgb = 0x00ff00;
	    float tex1 = span->tex_x1;
	    float tex2 = span->tex_x2;
	    float tey1 = span->tex_y1;
	    float tey2 = span->tex_y2;

	    /**
	     * Span が持つ 1 pixel 毎の
	     * テクスチャの座標
	     */
	    int tex_xpos;
	    int tex_ypos;

	    /**
	     * (tex_xpos, tex_ypos) の、ブロック内(上の図参照)での座標と
	     * そのブロックのアドレス(MainMemory)
	     */
	    int tex_localx;
	    int tex_localy;
	    uint32 *tex_addr;

	    int x = span->x;
	    int y = span->y;
	    int x_len = span->length_x;
	    float z = span->start_z;
	    float zpos = span->end_z;

	    // 座標が [0 .. split_screen_w-1] に入るように x,y を -1
	    int localx = getLocalX(x-1);
	    int localy = getLocalY(y-1);

	    if (x_len == 1) {
		if (x < rangex_start || rangex_end < x) {
		    continue;
		}

		tex_xpos = (int)((span->tex_width-1) * tex1);
		tex_ypos = (int)((span->tex_height-1) * tey1);

		if (zpos < zRow[localx + (rangex * localy)]) {
		    tex_addr = getTile(tex_xpos, tex_ypos,
				       span->tex_width, span->tex_addr);
		    tex_localx = tex_xpos % TEXTURE_SPLIT_PIXEL;
		    tex_localy = tex_ypos % TEXTURE_SPLIT_PIXEL;
		    
		    rgb = get_rgb(tex_localx, tex_localy, tex_addr);

		    zRow[localx + (rangex * localy)] = zpos;
		    linebuf[localy][localx] = rgb;
		}
	    } else {
		int js = (x < rangex_start) ? rangex_start - x : 0;
		int je = (x + x_len > rangex_end) ? rangex_end - x : x_len;
		float tex_x, tex_y, tex_z;

		for (int j = js; j <= je; j++) {
		    localx = getLocalX(x-1+j);

		    tex_z = z*(x_len-1-j)/(x_len-1) + zpos*j/(x_len-1);

		    tex_x = tex1*(x_len-1-j)/(x_len-1) + tex2*j/(x_len-1);
		    tex_y = tey1*(x_len-1-j)/(x_len-1) + tey2*j/(x_len-1);
		    /**
		     * ・・・なんかかっこいい書き方ないかな
		     */
		    if (tex_x > 1) tex_x = 1;
		    if (tex_x < 0) tex_x = 0;
		    if (tex_y > 1) tex_y = 1;
		    if (tex_y < 0) tex_y = 0;
		    tex_xpos = (int)((span->tex_width-1) * tex_x);
		    tex_ypos = (int)((span->tex_height-1) * tex_y);
		    
		    if (tex_z < zRow[localx + (rangex*localy)]) {
			tex_addr = getTile(tex_xpos, tex_ypos,
					   span->tex_width, span->tex_addr);
			tex_localx = tex_xpos % TEXTURE_SPLIT_PIXEL;
			tex_localy = tex_ypos % TEXTURE_SPLIT_PIXEL;
			
			rgb = get_rgb(tex_localx, tex_localy, tex_addr);
		    
			zRow[localx + (rangex*localy)] = tex_z;
			linebuf[localy][localx] = rgb;
		    }
		}
	    }
	}

	smanager->dma_wait(SPAN_PACK_LOAD);

	tmp_sp = sp;
	sp = next_sp;
	next_sp = tmp_sp;
    } while (sp);

    free(free_sp);
    free(linebuf);
    free(zRow);

    return 0;
}