#include "set_plot.h"
#include <math.h>

static double clamp(double v, double lo, double hi) { return fmin(hi, fmax(lo, v)); }
static int finite_values(const double *v, size_t n) {
    size_t i;
    for (i = 0; i < n; ++i) if (!isfinite(v[i])) return 0;
    return 1;
}

uint32_t set_plot_abi_version(void) { return 1U; }

size_t set_plot_eval(uint32_t op, const double *v, size_t n, double *out, size_t cap) {
    static const size_t sizes[] = {10, 3, 4, 4, 6, 2, 3, 2};
    double span, fraction;
    if (op > SET_PLOT_DB_DELTA || !v || !out || n != sizes[op] ||
        cap < (op == SET_PLOT_TRANSFORM ? 4U : 1U)) return 0;
    if (op == SET_PLOT_TRANSFORM) {
        double w, h, fx, fy;
        if (!finite_values(v, 4) || v[2] < 1.0/128 || v[2] > 1 ||
            v[3] < 1.0/128 || v[3] > 1 || v[0] < 0 || v[1] < 0 ||
            v[0] + v[2] > 1.000000000001 || v[1] + v[3] > 1.000000000001) return 0;
        out[0] = v[0]; out[1] = v[1]; out[2] = v[2]; out[3] = v[3];
        if (!finite_values(v + 4, 6) || v[4] <= 0 || v[5] <= 0) return 4;
        w = clamp(v[2] / v[4], 1.0/128, 1);
        h = clamp(v[3] / v[5], 1.0/128, 1);
        fx = clamp(v[8], 0, 1); fy = clamp(v[9], 0, 1);
        out[0] = clamp(v[0] + (v[2] - w) * fx - v[6] * w, 0, 1 - w);
        out[1] = clamp(v[1] + (v[3] - h) * fy - v[7] * h, 0, 1 - h);
        out[2] = w; out[3] = h;
        return 4;
    }
    if (!finite_values(v, n)) return 0;
    switch (op) {
    case SET_PLOT_AXIS:
        if (v[2] < 0) return 0;
        out[0] = fmax(fabs(v[0]), fabs(v[1])) <= v[2] ? 0 :
            (fabs(v[1]) > fabs(v[0]) ? 2 : 1);
        break;
    case SET_PLOT_FRACTION:
    case SET_PLOT_VALUE:
        span = v[2] - v[1];
        if (!isfinite(span) || span <= 0 || (v[3] != 0 && v[3] != 1)) return 0;
        if (op == SET_PLOT_FRACTION) {
            fraction = (v[0] - v[1]) / span;
            out[0] = v[3] ? 1 - fraction : fraction;
        } else {
            fraction = v[3] ? 1 - v[0] : v[0];
            out[0] = v[1] + fraction * span;
        }
        break;
    case SET_PLOT_DRAG:
        span = v[4] - v[3];
        if (!isfinite(span) || span <= 0 || v[2] <= 0 || (v[5] != 0 && v[5] != 1)) return 0;
        out[0] = clamp(v[0] + (v[5] ? -1 : 1) * (v[1] / v[2]) * span, v[3], v[4]);
        break;
    case SET_PLOT_TICK_STEP: {
        double raw, magnitude, scaled;
        if (v[0] <= 0 || v[1] <= 0) return 0;
        raw = v[0] / fmax(2, floor(v[1] / 100));
        magnitude = pow(10, floor(log10(raw)));
        if (magnitude <= 0 || !isfinite(magnitude)) return 0;
        scaled = raw / magnitude;
        out[0] = (scaled <= 1 ? 1 : scaled <= 2 ? 2 : scaled <= 5 ? 5 : 10) * magnitude;
        break;
    }
    case SET_PLOT_DELTA: out[0] = (v[1] - v[0]) * v[2]; break;
    case SET_PLOT_DB_DELTA:
        if (v[0] == 0 || v[1] == 0) return 0;
        out[0] = 20 * log10(fabs(v[1] / v[0]));
        break;
    default: return 0;
    }
    return isfinite(out[0]) ? 1 : 0;
}