#pragma version(1)
#pragma stateVertex(PV)
#pragma stateFragment(PFTexLinear)
#pragma stateStore(PSIcons)

#define PI 3.14159f

int g_SpecialHWWar;

// Attraction to center values from page edge to page center.
float g_AttractionTable[9];
float g_FrictionTable[9];
float g_PhysicsTableSize;

float g_PosPage;
float g_PosVelocity;
float g_LastPositionX;
int g_LastTouchDown;
float g_DT;
int g_LastTime;
int g_PosMax;
float g_Zoom;
float g_OldPosPage;
float g_OldPosVelocity;
float g_OldZoom;
float g_MoveToTotalTime;
float g_MoveToTime;
float g_MoveToOldPos;


// Drawing constants, should be parameters ======
#define VIEW_ANGLE 1.28700222f

int g_DrawLastFrame;
int lastFrame(int draw) {
    // We draw one extra frame to work around the last frame post bug.
    // We also need to track if we drew the last frame to deal with large DT
    // in the physics.
    int ret = g_DrawLastFrame | draw;
    g_DrawLastFrame = draw;
    return ret;  // should return draw instead.
}

void updateReadback() {
    if ((g_OldPosPage != g_PosPage) ||
        (g_OldPosVelocity != g_PosVelocity) ||
        (g_OldZoom != g_Zoom)) {

        g_OldPosPage = g_PosPage;
        g_OldPosVelocity = g_PosVelocity;
        g_OldZoom = g_Zoom;

        int i[3];
        i[0] = g_PosPage * (1 << 16);
        i[1] = g_PosVelocity * (1 << 16);
        i[2] = g_OldZoom * (1 << 16);
        sendToClient(&i[0], 1, 12, 1);
    }
}

void setColor(float r, float g, float b, float a) {
    if (g_SpecialHWWar) {
        color(0, 0, 0, 0.001f);
    } else {
        color(r, g, b, a);
    }
}

void init() {
    g_AttractionTable[0] = 20.0f;
    g_AttractionTable[1] = 20.0f;
    g_AttractionTable[2] = 15.0f;
    g_AttractionTable[3] = 10.0f;
    g_AttractionTable[4] = -10.0f;
    g_AttractionTable[5] = -15.0f;
    g_AttractionTable[6] = -15.0f;
    g_AttractionTable[7] = -20.0f;
    g_AttractionTable[8] = -20.0f;  // dup 7 to avoid a clamp later
    g_FrictionTable[0] = 10.0f;
    g_FrictionTable[1] = 10.0f;
    g_FrictionTable[2] = 11.0f;
    g_FrictionTable[3] = 15.0f;
    g_FrictionTable[4] = 15.0f;
    g_FrictionTable[5] = 11.0f;
    g_FrictionTable[6] = 10.0f;
    g_FrictionTable[7] = 10.0f;
    g_FrictionTable[8] = 10.0f;  // dup 7 to avoid a clamp later
    g_PhysicsTableSize = 7;

    g_PosVelocity = 0;
    g_PosPage = 0;
    g_LastTouchDown = 0;
    g_LastPositionX = 0;
    g_Zoom = 0;
    g_SpecialHWWar = 1;
    g_MoveToTime = 0;
    g_MoveToOldPos = 0;
    g_MoveToTotalTime = 0.2f; // Duration of scrolling 1 line
}

void resetHWWar() {
    g_SpecialHWWar = 1;
}

void move() {
    if (g_LastTouchDown) {
        float dx = -(state->newPositionX - g_LastPositionX);
        g_PosVelocity = 0;
        g_PosPage += dx * 4;

        float pmin = -0.25f;
        float pmax = g_PosMax + 0.25f;
        g_PosPage = clampf(g_PosPage, pmin, pmax);
    }
    g_LastTouchDown = state->newTouchDown;
    g_LastPositionX = state->newPositionX;
    g_MoveToTime = 0;
    //debugF("Move P", g_PosPage);
}

void moveTo() {
    g_MoveToTime = g_MoveToTotalTime;
    g_PosVelocity = 0;
    g_MoveToOldPos = g_PosPage;

	// debugF("======= moveTo", state->targetPos);
}

void fling() {
    g_LastTouchDown = 0;
    g_PosVelocity = -state->flingVelocity * 4;
    float av = fabsf(g_PosVelocity);
    float minVel = 3.5f;

    minVel *= 1.f - (fabsf(fracf(g_PosPage + 0.5f) - 0.5f) * 0.45f);

    if (av < minVel && av > 0.2f) {
        if (g_PosVelocity > 0) {
            g_PosVelocity = minVel;
        } else {
            g_PosVelocity = -minVel;
        }
    }

    if (g_PosPage <= 0) {
        g_PosVelocity = maxf(0, g_PosVelocity);
    }
    if (g_PosPage > g_PosMax) {
        g_PosVelocity = minf(0, g_PosVelocity);
    }
}

float
modf(float x, float y)
{
    return x-(y*floorf(x/y));
}


/*
 * Interpolates values in the range 0..1 to a curve that eases in
 * and out.
 */
float
getInterpolation(float input) {
    return (cosf((input + 1) * PI) / 2.0f) + 0.5f;
}


void updatePos() {
    if (g_LastTouchDown) {
        return;
    }

    int outOfRange = 0;
    float tablePosNorm = fracf(g_PosPage + 0.5f);
    float tablePosF = tablePosNorm * g_PhysicsTableSize;
    int tablePosI = tablePosF;
    float tablePosFrac = tablePosF - tablePosI;
    float accel = lerpf(g_AttractionTable[tablePosI],
                        g_AttractionTable[tablePosI + 1],
                        tablePosFrac) * g_DT;
    float friction = lerpf(g_FrictionTable[tablePosI],
                        g_FrictionTable[tablePosI + 1],
                        tablePosFrac) * g_DT;

    if (g_MoveToTime) {

		/*
        float a = 2.f * (state->targetPos - g_MoveToOldPos) /
                  (g_MoveToTotalTime * g_MoveToTotalTime);
        if (g_MoveToTime > (g_MoveToTotalTime * 0.5f)) {
            // slowing
            g_PosPage = state->targetPos - 0.5f * a * (g_MoveToTime * g_MoveToTime);
        } else {
            // accelerating.
            float t = g_MoveToTotalTime - g_MoveToTime;
            g_PosPage = g_MoveToOldPos + 0.5f * a * (t * t);
        }
		 */

		// New position is old posiition + (total distance) * (interpolated time)
		g_PosPage = g_MoveToOldPos + (state->targetPos - g_MoveToOldPos) * getInterpolation((g_MoveToTotalTime - g_MoveToTime) / g_MoveToTotalTime);

        g_MoveToTime -= g_DT;
        if (g_MoveToTime <= 0) {
            g_MoveToTime = 0;
            g_PosPage = state->targetPos;
        }
        return;
    }

    if (g_PosPage < -0.5f) {
        accel = g_AttractionTable[0] * g_DT;
        outOfRange = 1;
    }
    if ((g_PosPage - g_PosMax) > 0.5f) {
        accel = g_AttractionTable[(int)g_PhysicsTableSize] * g_DT;
        outOfRange = 1;
    }

    // If our velocity is low OR acceleration is opposing it, apply it.
    if (fabsf(g_PosVelocity) < 2.5f || (g_PosVelocity * accel) < 0 || outOfRange) {
        g_PosVelocity += accel;
    }

    if ((friction > fabsf(g_PosVelocity)) &&
        (friction > fabsf(accel)) &&
        !outOfRange) {
        // Special get back to center and overcome friction physics.
        float t = tablePosNorm - 0.5f;
        if (fabsf(t) < (friction * g_DT)) {
            // really close, just snap
            g_PosPage = roundf(g_PosPage);
            g_PosVelocity = 0;
        } else {
            if (t > 0) {
                g_PosVelocity = -friction;
            } else {
                g_PosVelocity = friction;
            }
        }
    } else {
        // Normal physics
        if (g_PosVelocity > 0) {
            g_PosVelocity -= friction;
            g_PosVelocity = maxf(g_PosVelocity, 0);
        } else {
            g_PosVelocity += friction;
            g_PosVelocity = minf(g_PosVelocity, 0);
        }
    }
    g_PosPage += g_PosVelocity * g_DT;

    // Check for out of boundry conditions.
    if (g_PosPage < 0 && g_PosVelocity < 0) {
        g_PosPage = maxf(g_PosPage, -0.49);
        float damp = 1.0 + (g_PosPage * 4);
        damp = clampf(damp, 0.f, 0.9f);
        g_PosVelocity *= damp;
    }
    if (g_PosPage > g_PosMax && g_PosVelocity > 0) {
        g_PosPage = minf(g_PosPage, g_PosMax + 0.49);
        float damp = 1.0 - ((g_PosPage - g_PosMax) * 4);
        damp = clampf(damp, 0.f, 0.9f);
        g_PosVelocity *= damp;
    }
}

int positionStrip(float row, float column, int isTop, float p)
{
    float mat1[16];
    float x = 0.5f * (column - 1.5f);
    float scale = 72.f * 3 / getWidth();

    if (isTop) {
        matrixLoadTranslate(mat1, x, 0.8f, 0.f);
        matrixScale(mat1, scale, scale, 1.f);
    } else {
        matrixLoadTranslate(mat1, x, -0.9f, 0.f);
        matrixScale(mat1, scale, -scale, 1.f);
    }
    matrixTranslate(mat1, 0, p * 2, 0.f);
    matrixRotate(mat1, -p * 50, 1, 0, 0);
    vpLoadModelMatrix(mat1);

    float soff = -(row * 1.4);
    if (isTop) {
        matrixLoadScale(mat1, 1.f, -0.85f, 1.f);
        matrixTranslate(mat1, 0, soff - 0.97f, 0);
    } else {
        matrixLoadScale(mat1, 1.f, 0.85f, 1.f);
        matrixTranslate(mat1, 0, soff - 0.45f, 0);
    }
    vpLoadTextureMatrix(mat1);
    return -soff * 10.f;
}

void
draw_home_button()
{
    setColor(1.0f, 1.0f, 1.0f, 1.0f);
    bindTexture(NAMED_PFTexLinear, 0, state->homeButtonId);
    float x = (SCREEN_WIDTH_PX - params->homeButtonTextureWidth) / 2;
    float y = (g_Zoom - 1.f) * params->homeButtonTextureHeight;

    y -= 36; // move the house to the edge of the screen as it doesn't fill the texture.
    drawSpriteScreenspace(x, y, 0, params->homeButtonTextureWidth, params->homeButtonTextureHeight);
}

void drawFrontGrid(float rowOffset, float p)
{
    float h = getHeight();
    float w = getWidth();

    int intRowOffset = rowOffset;
    float rowFrac = rowOffset - intRowOffset;
    float colWidth = getWidth() / 4;
    float rowHeight = colWidth + 25.f;
    float yoff = h - ((h - (rowHeight * 4.f)) / 2);

    yoff -= 110;

    int row, col;
    int iconNum = intRowOffset * 4;
    float ymax = yoff;
    float ymin = yoff - (3 * rowHeight) - 70;

    for (row = 0; row < 5; row++) {
        float y = yoff - ((-rowFrac + row) * rowHeight);

        for (col=0; col < 4; col++) {
            if (iconNum >= state->iconCount) {
                return;
            }

            if (iconNum >= 0) {
                float x = colWidth * col - ((128 - colWidth) / 2);

                if ((y >= ymin) && (y <= ymax)) {
                    setColor(1.f, 1.f, 1.f, 1.f);

                    if (state->selectedIconIndex == iconNum && !p) {
                        bindTexture(NAMED_PFTexLinear, 0, state->selectedIconTexture);
                        drawSpriteScreenspace(x, y, 0, 128, 128);
                    }

                    bindTexture(NAMED_PFTexLinear, 0, loadI32(ALLOC_ICON_IDS, iconNum));
                    if (!p) {
                        drawSpriteScreenspace(x, y, 0, 128, 128);
                    } else {
                        float px = ((x + 64) - (getWidth() / 2)) / (getWidth() / 2);
                        float py = ((y + 64) - (getHeight() / 2)) / (getWidth() / 2);
                        float d = 64.f / (getWidth() / 2);
                        px *= p + 1;
                        py *= p + 1;
                        drawQuadTexCoords(px - d, py - d, -p, 0, 1,
                                          px - d, py + d, -p, 0, 0,
                                          px + d, py + d, -p, 1, 0,
                                          px + d, py - d, -p, 1, 1);
                    }
                }

                float y2 = y - 44;
                float a = 1.f;
                if (y2 < ymin) {
                    a = 1.f - (ymin - y2) * 0.02f;
                }
                if (y > (ymax + 40)) {
                    a = 1.f - (y - (ymax + 40)) * 0.02f;
                }
                a = clampf(a, 0, 1);
                a *= maxf(0, 1.f - p * 5.f);

                setColor(1, 1, 1, a);
                bindTexture(NAMED_PFTexLinear, 0, loadI32(ALLOC_LABEL_IDS, iconNum));
                drawSpriteScreenspace(x, y - 44, 0,
                           params->bubbleBitmapWidth, params->bubbleBitmapHeight);
            }
            iconNum++;
        }
    }
}

void drawStrip(float row, float column, int isTop, int iconNum, float p)
{
    if (iconNum < 0) return;
    int offset = positionStrip(row, column, isTop, p);
    bindTexture(NAMED_PFTexLinear, 0, loadI32(ALLOC_ICON_IDS, iconNum));
    if (offset < -20) return;
    offset = clamp(offset, 0, 199 - 20);
    drawSimpleMeshRange(NAMED_SMMesh, offset * 6, 20 * 6);
}

void drawTop(float rowOffset, float p)
{
    int row, col;
    int iconNum = 0;
    for (row = 0; row < rowOffset; row++) {
        for (col=0; col < 4; col++) {
            if (iconNum >= state->iconCount) {
                return;
            }
            drawStrip(rowOffset - row, col, 1, iconNum, p);
            iconNum++;
        }
    }
}

void drawBottom(float rowOffset, float p)
{
    float pos = -1.f;
    int intRowOffset = rowOffset;
    pos -= rowOffset - intRowOffset;

    int row, col;
    int iconNum = (intRowOffset + 3) * 4;
    while (1) {
        for (col=0; col < 4; col++) {
            if (iconNum >= state->iconCount) {
                return;
            }
            if (pos > -1) {
                drawStrip(pos, col, 0, iconNum, p);
            }
            iconNum++;
        }
        pos += 1.f;
    }
}

int
main(int launchID)
{
    // Compute dt in seconds.
    int newTime = uptimeMillis();
    g_DT = (newTime - g_LastTime) / 1000.f;
    g_LastTime = newTime;

    if (!g_DrawLastFrame) {
        // If we stopped rendering we cannot use DT.
        // assume 30fps in this case.
        g_DT = 0.033f;
    }
    // physics may break if DT is large.
    g_DT = minf(g_DT, 0.2f);

    if (g_Zoom != state->zoomTarget) {
        float dz;
        if (state->zoomTarget > 0.5f) {
            dz = (1 - g_Zoom) * 0.2f;
        } else {
            dz = -g_DT - (1 - g_Zoom) * 0.2f;
        }
        if (dz && (fabsf(dz) < 0.02f)) {
            if (dz > 0) {
                dz = 0.02f;
            } else {
                dz = -0.02f;
            }
        }
        if (fabsf(g_Zoom - state->zoomTarget) < fabsf(dz)) {
            g_Zoom = state->zoomTarget;
        } else {
            g_Zoom += dz;
        }
        updateReadback();
    }

    // Set clear value to dim the background based on the zoom position.
    if ((g_Zoom < 0.001f) && (state->zoomTarget < 0.001f) && !g_SpecialHWWar) {
        pfClearColor(0.0f, 0.0f, 0.0f, 0.0f);
        // When we're zoomed out and not tracking motion events, reset the pos to 0.
        if (!g_LastTouchDown) {
            g_PosPage = 0;
        }
        return lastFrame(0);
    } else {
        pfClearColor(0.0f, 0.0f, 0.0f, g_Zoom);
    }

    // icons & labels
    int iconCount = state->iconCount;
    g_PosMax = ((iconCount + 3) / 4) - 4;
    if (g_PosMax < 0) g_PosMax = 0;

    updatePos(0.1f);
    updateReadback();

    //debugF("    draw g_PosPage", g_PosPage);

    // Draw the icons ========================================

    //bindProgramFragment(NAMED_PFColor);
    //positionStrip(1, 0, 0);
    //drawSimpleMesh(NAMED_SMMesh);

    bindProgramFragment(NAMED_PFTexLinear);


    drawTop(g_PosPage, 1-g_Zoom);
    drawBottom(g_PosPage, 1-g_Zoom);

    {
        float mat1[16];
        matrixLoadIdentity(mat1);
        vpLoadModelMatrix(mat1);
        vpLoadTextureMatrix(mat1);
    }
    drawFrontGrid(g_PosPage, 1-g_Zoom);
    draw_home_button();


    // This is a WAR to do a rendering pass without drawing during init to
    // force the driver to preload and compile its shaders.
    // Without this the first animation does not appear due to the time it
    // takes to init the driver state.
    if (g_SpecialHWWar) {
        g_SpecialHWWar = 0;
        return 1;
    }

    // Bug workaround where the last frame is not always displayed
    // So we keep rendering until the bug is fixed.
    return lastFrame((g_PosVelocity != 0) || fracf(g_PosPage) || g_Zoom != state->zoomTarget || (g_MoveToTime != 0));
}