#include <cmath>
#include <pugl/pugl.h>
#include "pui.h"

float Knob::GetNewValue(int x, int y)
{
	int dx = (this->x + this->w / 2) - x;
	int dy = (this->y + this->h / 2) - y;

	float a = .5f - (atan2(dx, dy) * .5f / M_PI) * 1.33f;
	if (a < 0) a = 0;
	if (a > 1) a = 1;

	return a * (max - min) + min;
}

static void DrawPartial(GLuint t1, GLuint t2, int seg, float x1, float y1, float x2, float y2, float r)
{
	float xc = .5f;
	float yc = .5f;

	if (r >= 0 && r <= .25f) {
		float t;
		if (r <= .125f) {
			t = .5 - tanf((.125f - r) * 2 * M_PI) * .5f;
		} else {
			t = .5 + tanf((r - .125f) * 2 * M_PI) * .5f;
		}
		float x, y;
		switch (seg) {
			default:
			case 0: x = x1; y = 1 - t; break;
			case 1: x = t; y = y1; break;
			case 2: x = x1; y = t; break;
			case 3: x = 1 - t; y = y1; break;
		}

		glBindTexture(GL_TEXTURE_2D, t2);
		glBegin(GL_TRIANGLES);
		glTexCoord2f(xc, yc);
		glVertex2f(xc, yc);
		glTexCoord2f(x1, y1);
		glVertex2f(x1, y1);
		glTexCoord2f(x, y);
		glVertex2f(x, y);
		glEnd();

		glBindTexture(GL_TEXTURE_2D, t1);
		glBegin(GL_TRIANGLES);
		glTexCoord2f(xc, yc);
		glVertex2f(xc, yc);
		glTexCoord2f(x, y);
		glVertex2f(x, y);
		glTexCoord2f(x2, y2);
		glVertex2f(x2, y2);
		glEnd();
	} else {
		glBindTexture(GL_TEXTURE_2D, r > 0 ? t2 : t1);
		glBegin(GL_TRIANGLES);
		glTexCoord2f(xc, yc);
		glVertex2f(xc, yc);
		glTexCoord2f(x1, y1);
		glVertex2f(x1, y1);
		glTexCoord2f(x2, y2);
		glVertex2f(x2, y2);
		glEnd();
	}
}

void Knob::OnPaint(const PUi *pui) const
{
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glEnable(GL_BLEND);
	glEnable(GL_TEXTURE_2D);

	float mx = (w - pui->w[TEX_KNOB]) * 0.5f + x;
	float my = (h - pui->h[TEX_KNOB]) * 0.5f + y;

	float hw = pui->w[TEX_KNOB] * .5f;
	float hh = pui->h[TEX_KNOB] * .5f;

	glPushMatrix();
	glTranslatef(mx, my, 0);
	glColor3f(1, 1, 1);

	glScalef(pui->w[TEX_KNOB], pui->h[TEX_KNOB], 1);

	GLuint t1 = pui->tex[TEX_KNOB];
	GLuint t2 = pui->tex[TEX_KNOB_PRE];

	float r = (this->value - this->min) / (this->max - this->min) - .5f;
	r /= 1.3333f;
	r += .5f;

	r -= .125f;
	DrawPartial(t1, t2, 0, 0, 1, 0, 0, r);
	r -= .25f;
	DrawPartial(t1, t2, 1, 0, 0, 1, 0, r);
	r -= .25f;
	DrawPartial(t1, t2, 2, 1, 0, 1, 1, r);
	r -= .25f;
	DrawPartial(t1, t2, 3, 1, 1, 0, 1, r);

	glPopMatrix();
	r = (this->value - this->min) / (this->max - this->min) - .5f;

	glPushMatrix();
	glTranslatef(mx + hw, my + hw, 0);
	glRotatef(r * 270, 0, 0, 1);
	glBindTexture(GL_TEXTURE_2D, pui->tex[TEX_KNOB_SEL]);
	glBegin(GL_QUADS);
	glColor3f(1.0, 1.0, 1.0);
	glTexCoord2f(0, 0);
	glVertex2f(-hw, -hh);
	glTexCoord2f(0, 1);
	glVertex2f(-hw,  hh);
	glTexCoord2f(1, 1);
	glVertex2f( hw,  hh);
	glTexCoord2f(1, 0);
	glVertex2f( hw, -hh);
	glEnd();

	glPopMatrix();
	glDisable(GL_TEXTURE_2D);

	char tmp[128];
	snprintf(tmp, sizeof tmp, "%s: %06d", this->label, (int)(this->value * 44100));
	FTBBox box = pui->font->BBox(tmp);
	FTPoint p = box.Upper() - box.Lower();
	float cx = p.X();
	float cy = p.Y();

	float ox = -.5f;
	float oy = 0;

	glPushMatrix();
	glTranslatef(x + w * 0.5f, y - 4, 0);
	glScalef(.5f, -.5f, 1);
	glTranslatef(cx * ox, -cy * oy, 0);
	glColor4f(0, 0, 0, 1);
	pui->font->Render(tmp);
	glTranslatef(0, 2, 0);
	glColor4f(1, 1, 1, 1);
	pui->font->Render(tmp);
	glPopMatrix();

	Widget::OnPaint(pui);
}