/* post.c -- POST's runner: the kernel feeds a case to the node and judges it
 * from outside.  See post.h; docs/v4.0.0/NUCLEUS.md section 6.3.
 *
 * Nothing here uses the C library: the bare-metal kernel links this file.
 */
#include "v4/post.h"
#include "v4/message.h"

#define SHOWN_OUT   255u             /* how much of a failing case's printing is shown */
#define SHOWN_STACK 32u              /* and how many of the values it left */

static const char state_line[] = "DECIMAL FORTH DEFINITIONS";

static unsigned length(const char *s)
{
    unsigned n = 0;
    while (s[n]) n++;
    return n;
}

static void say(const v4_post_host *h, const char *s)
{
    h->say(h->self, s, length(s));
}

static void say_number(const v4_post_host *h, long long v)
{
    char text[24];
    unsigned at = sizeof text;
    unsigned long long u = v < 0 ? 0ull - (unsigned long long)v : (unsigned long long)v;

    do { text[--at] = (char)('0' + u % 10u); u /= 10u; } while (u);
    if (v < 0) text[--at] = '-';
    h->say(h->self, text + at, (unsigned)sizeof text - at);
}

int v4_post_run(const v4_post_host *h, const v4_post_case *cases, unsigned count, v4_post_tally *tally)
{
    static char out[V4_POST_OUT];    /* what the case being run has printed */
    v4_cell left[SHOWN_STACK];       /* what it left on the stack, the top first */
    unsigned i, k;

    tally->tests = 0; tally->pass = 0; tally->fail = 0;
    for (i = 0; i < count; i++) {
        const v4_post_case *c = &cases[i];
        unsigned kept = 0, total = 0, len = 0, depth;
        int errored = 0, came_back = 1, lost = 0, no_state = 0, quit = 0, ok, how;

        /* every case starts from the same state */
        v4_dstack_reset(&h->n->ds);
        how = h->line(h->self, state_line, (unsigned)sizeof state_line - 1u, out, V4_POST_OUT, &len);
        if (how < 0) lost = 1;
        if (how != V4_TEXT_COMPLETED) {              /* what the node said of it is what is shown */
            came_back = 0; no_state = 1;
            total = len; kept = len < V4_POST_OUT ? len : V4_POST_OUT;
        }
        v4_dstack_reset(&h->n->ds);

        for (k = 0; came_back && k < c->line_count; k++) {
            len = 0;
            how = h->line(h->self, c->lines[k], length(c->lines[k]), out + kept, V4_POST_OUT - kept, &len);
            if (how < 0) { came_back = 0; lost = 1; break; }
            if (how == V4_TEXT_ERROR) errored = 1;
            if (how == V4_TEXT_QUIT) quit = 1;       /* it went back to the terminal: it did not complete */
            total += len;
            kept = total < V4_POST_OUT ? total : V4_POST_OUT;
        }

        /* what it left, read before anything is judged */
        depth = h->n->ds.depth;
        for (k = 0; k < depth; k++) {
            v4_cell v = v4_dstack_pop(&h->n->ds);
            if (k < SHOWN_STACK) left[k] = v;
        }
        v4_dstack_reset(&h->n->ds);

        if (!came_back || quit) {
            ok = 0;
        } else if (c->expect == V4_POST_ERROR) {
            ok = errored;
        } else if (errored) {
            ok = 0;
        } else {
            ok = depth == c->depth;
            if (ok && c->expect == V4_POST_STACK) {
                if (depth > SHOWN_STACK) ok = 0;
                for (k = 0; ok && k < depth; k++) ok = left[k] == (v4_cell)c->stack[depth - 1u - k];
            }
            if (ok && c->expect != V4_POST_DEPTH) {
                ok = total == c->output_len && total <= V4_POST_OUT;
                for (k = 0; ok && k < total; k++) ok = out[k] == c->output[k];
            }
        }

        tally->tests++;
        if (ok) { tally->pass++; continue; }
        tally->fail++;
        say(h, "POST FAIL: "); say(h, c->name);
        if (no_state) say(h, " could not be put in its starting state:");
        if (quit) say(h, " ended with QUIT:");
        say(h, " out<"); h->say(h->self, out, kept < SHOWN_OUT ? kept : SHOWN_OUT);
        say(h, "> stack<");
        for (k = depth < SHOWN_STACK ? depth : SHOWN_STACK; k-- > 0; ) { say_number(h, (long long)left[k]); say(h, " "); }
        say(h, ">\n");

        /* The node did not come back from a line: it is stopped, or will
         * run for ever.  Nothing more can be asked of it, so POST ends
         * here and says which case it was. */
        if (lost) {
            say(h, "POST: the node did not come back from "); say(h, c->name);
            say(h, "; "); say_number(h, (long long)(count - i - 1u)); say(h, " not run\n");
            break;
        }
    }
    say(h, "PARITY:V4_POST tests="); say_number(h, (long long)tally->tests);
    say(h, " pass="); say_number(h, (long long)tally->pass);
    say(h, " fail="); say_number(h, (long long)tally->fail);
    say(h, "\n");
    return tally->fail == 0;
}