// Pacer unit tests: given a clock sequence, the expected wait durations are hand-calculated. The period 16.666 ms is written as P = 16666667 ns.
#include "../nvn/nvn_pace.h"
#include <stdio.h>

int main(void) {
    const uint64_t P = 16666667, MS = 1000000;
    struct { uint64_t now, period, want; const char *why; } c[] = {
        {1000 * MS, P, 0, "first frame: starts the beat, no wait"},
        {1005 * MS, P, 1000 * MS + P - 1005 * MS, "5 ms early: wait until 1000+P"},
        {1000 * MS + 2 * P - 2 * MS, P, 2 * MS, "third frame 2 ms early: wait 2 ms"},
        {1000 * MS + 3 * P + 3 * MS, P, 0, "3 ms late (less than a period): present at once, beat point stays 1000+3P"},
        {1000 * MS + 4 * P - 1 * MS, P, 1 * MS, "next frame 1 ms early: wait until 1000+4P in the original phase"},
        {1000 * MS + 7 * P, P, 0, "two periods behind (stall): restart the beat now, no burst to catch up"},
        {1000 * MS + 7 * P + 4 * MS, P, P - 4 * MS, "next frame after the restart: wait until the new target"},
        {1000 * MS + 9 * P, 0, 0, "period 0 (DM_PRESENT_HZ=0): no wait"},
        {1000 * MS + 9 * P + 1 * MS, 2 * P, 2 * P - 1 * MS, "back to interval 2: beat point = previous frame time 9P + 2P"},
        {1000 * MS + 11 * P + 3 * MS, 2 * P, 2 * P - 3 * MS, "interval 2, next frame: beat point 13P"},
    };
    nvn_pacer p = {0}; int fail = 0, n = sizeof c / sizeof *c;
    for (int i = 0; i < n; i++) {
        uint64_t got = nvn_pace(&p, c[i].now, c[i].period);
        int ok = got == c[i].want;
        printf("%-52s expected wait %8.3f ms → got %8.3f ms %s\n", c[i].why, c[i].want / 1e6, got / 1e6, ok ? "✓" : "✗");
        fail += !ok;
    }
    printf("== %d checks, %d failed ==\n", n, fail);
    return fail != 0;
}