#include "math.h"


// Angle conversion constants.
const double fromRadians = 10430.378350470453;     // 65536 / 2π
const double toRadians   = 0.00009587379924285257; // 2π / 65536


// Reset the math device.
void math_reset(MathDevice *math) {
    math->x = 0;
    math->y = 0;
    math->r = 0;
    math->t = 0;
    math_clear_cartesian(math);
    math_clear_polar(math);
}

// Clear all values calculated from cartesian coordinates.
void math_clear_cartesian(MathDevice *math) {
    math->r_cached    = false;
    math->t_cached    = false;
    math->prod_cached = false;
    math->quot_cached = false;
    math->rem_cached  = false;
}

// Clear all values calculated from polar coordinates.
void math_clear_polar(MathDevice *math) {
    math->x_cached    = false;
    math->y_cached    = false;
}

// Calculate the x coordinate of the polar point.
s16 math_get_x(MathDevice *math) {
    if (!math->x_cached) {
        double x = cos(math->t * toRadians) * math->r;
        if (-32768.0 <= x && x <= 32768.0) {
            math->x_read = x;
        } else {
            math->x_read = 0;
        }
        math->x_cached = true;
    }
    return math->x_read;
}

// Calculate the y coordinate of the polar point.
s16 math_get_y(MathDevice *math) {
    if (!math->y_cached) {
        double y = sin(math->t * toRadians) * math->r;
        if (-32768.0 <= y && y <= 32767.0) {
            math->y_read = y;
        } else {
            math->y_read = 0;
        }
        math->y_cached = true;
    }
    return math->y_read;
}

// Calculate the r coordinate of the cartesian point.
u16 math_get_r(MathDevice *math) {
    if (!math->r_cached) {
        u32 x2 = math->x * math->x;
        u32 y2 = math->y * math->y;
        math->r_read = sqrt32(x2 + y2);
        math->r_cached = true;
    }
    return math->r_read;
}

// Calculate the t coordinate of the cartesian point.
u16 math_get_t(MathDevice *math) {
    if (!math->t_cached) {
        if (math->x || math->y) {
            math->t_read = atan2(math->y, math->x) * fromRadians;
        } else {
            math->t_read = 0;
        }
        math->t_cached = true;
    }
    return math->t_read;
}

// Calculate the product of x by y.
u32 math_get_prod(MathDevice *math) {
    if (!math->prod_cached) {
        math->prod_read = (u16)math->x * (u16)math->y;
        math->prod_cached = true;
    }
    return math->prod_read;
}

// Calculate the quotient of x by y.
u16 math_get_quot(MathDevice *math) {
    if (!math->quot_cached) {
        if (math->y) {
            math->quot_read = div32((u16)math->x, (u16)math->y);
        } else {
            math->quot_read = 0;
        }
        math->quot_cached = true;
    }
    return math->quot_read;
}

// Calculate the remainder of x by y.
u16 math_get_rem(MathDevice *math) {
    if (!math->rem_cached) {
        if (math->y) {
            math->rem_read = mod32((u16)math->x, (u16)math->y);
        } else {
            math->rem_read = 0;
        }
        math->rem_cached = true;
    }
    return math->rem_read;
}