#include <allegro.h>
#include <stdarg.h>
#include "lighting.h"

static void find_vlines_helper(Polygon* poly, va_list ap);
static void draw_vlines_helper(VLine* vline, va_list ap);

/* Returns a fresh vline */
VLine* create_vline(void)
{
	return calloc(1, sizeof(VLine));
}

/* Deallocates a vline */
void destroy_vline(VLine* vline)
{
	free(vline);
}

/* Makes a vline for every applicable edge in the world list of polygons */
void find_vlines(Heap* lines, Heap* world)
{
	empty_heap(lines);
	process_heap_va(world, PROC_VA(find_vlines_helper), lines);
}

/* Renders the list of vlines to bmp */
void draw_vlines(BITMAP* bmp, int x, int y, Heap* lines, int color)
{
//	int r, g, b;
	void** data = lines->data;
	void** data_end = data + lines->count;
	VLine* vline;
//	color = -1;
//	drawing_mode(DRAW_MODE_TRANS, NULL, 0, 0);
//	text_mode(-1);
	for (; data < data_end; data++) {
		vline = *data;
//		color++;
		if (vline->vtx_count != 2) {
//			if (vline->vtx_count == 1)
//				circle(buffer, vline->xa, vline->ya, 2,
//						0xffffff);
			continue;
		}
		triangle(bmp, x, y, vline->xa, vline->ya, vline->xb, vline->yb,
				color);
//		hsv_to_rgb(color * 360.0 / 6.0, 1.0, 0.5, &r, &g, &b);
//		triangle(buffer, x, y, vline->xa, vline->ya, vline->xb,
//				vline->yb, makecol32(r, g, b));
//		textprintf_centre(buffer, font, (vline->x1 + vline->x2) / 2,
//				(vline->y1 + vline->y2) / 2 - 4,
//				makecol32(r, g, b), "%i", color);
//		line(buffer, vline->xa, vline->ya, vline->xb, vline->yb,
//				0xffffff);
	}
//	drawing_mode(DRAW_MODE_SOLID, NULL, 0, 0);
//	process_heap_va(lines, PROC_VA(draw_vlines_helper), bmp, x, y, color);
}

/* Adds a vertex to the given vline */
void add_vertex_to_vline(VLine* vline, int x, int y)
{
	static int recurse = 0;
	switch (vline->vtx_count) {
	case 0:
		vline->xa = x;
		vline->ya = y;
		vline->vtx_count = 1;
		break;
	case 1:
		if (vline->xa == x && vline->ya == y) break;
		vline->xb = x;
		vline->yb = y;
		vline->vtx_count = 2;
		break;
	case 2:
		switch (middle_point(x, y, vline->xa, vline->ya, vline->xb,
				vline->yb)) {
		case 2:
			vline->xa = x;
			vline->ya = y;
			break;
		case 3:
			vline->xb = x;
			vline->yb = y;
			break;
		}
		break;
	}
	if (recurse == 0 && vline->next != NULL) {
		recurse = 1;
		if (vline->x1 == x && vline->y1 == y)
			add_vertex_to_vline(vline->prev, x, y);
		else if (vline->x2 == x && vline->y2 == y)
			add_vertex_to_vline(vline->next, x, y);
		recurse = 0;
	}
}

/* Make a set of vlines for a polygon */
static void find_vlines_helper(Polygon* poly, va_list ap)
{
	int i, x, y;
	VLine* new_line;
	VLine* first_line;
	VLine* prev_line = NULL;
	Heap* lines = va_arg(ap, Heap*);

	if (poly->vtx_count < 3) return;
	x = poly->vtx[0].x;
	y = poly->vtx[0].y;
	for (i = 1; i <= poly->vtx_count; i++) {
		new_line = new_from_heap(lines);
		new_line->x1 = x;
		new_line->y1 = y;
		new_line->x2 = x = poly->vtx[i < poly->vtx_count ? i : 0].x;
		new_line->y2 = y = poly->vtx[i < poly->vtx_count ? i : 0].y;
		new_line->vtx_count = 0;
		new_line->skip = 0;
		if (prev_line == NULL)
			first_line = new_line;
		else {
			new_line->prev = prev_line;
			prev_line->next = new_line;
		}
		prev_line = new_line;
	}
	first_line->prev = prev_line;
	prev_line->next = first_line;
}

/* Draw a single VLine */
static void draw_vlines_helper(VLine* vline, va_list ap)
{
	if (vline->vtx_count == 2) {
		BITMAP* bmp;
		int x, y, color;
		bmp = va_arg(ap, BITMAP*);
		x = va_arg(ap, int);
		y = va_arg(ap, int);
		color = va_arg(ap, int);
		triangle(bmp, x, y, vline->xa, vline->ya, vline->xb, vline->yb,
				color);
		triangle(buffer, x, y, vline->xa, vline->ya, vline->xb, vline->yb,
				0x3f3f3f);
		line(buffer, x, y, vline->xa, vline->ya, 0x7f7f7f);
		line(buffer, x, y, vline->xb, vline->yb, 0x7f7f7f);
		line(buffer, vline->xa, vline->ya, vline->xb, vline->yb, 0xffffff);
	}
}