/* rom_harness.h -- run the ROM's routines on a host node, for tests.
 *
 * The ROM (capsules/v4/rom, built by tools/mkrom.c into $(BINDIR)/rom-<w>.c)
 * is attached to a host node as the machine's ROM.  A routine is called
 * through the ROM's entry table, as a payload calls it (MACHINE.md 2.1): the
 * table's order is fixed, and is rom_entries[] below.  Where a test needs to
 * know whether P is inside a routine, the ROM's symbols are read from
 * $(BINDIR)/rom-<w>.sym (V4_ROM_SYM).
 */
#ifndef V4_TESTS_ROM_HARNESS_H
#define V4_TESTS_ROM_HARNESS_H

#include "v4/testcode.h"
#include "host_map.h"
#include "v4/sys_files.h"
#include "v4/rom_entries.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* A mesh node's ROM (MACHINE.md 2.2): the shared math only. */
#if V4_CELL_BITS == 64
extern const v4_cell v4_mesh_rom_64[];
extern const unsigned v4_mesh_rom_64_words;
#define MESH_ROM v4_mesh_rom_64
#define MESH_ROM_WORDS v4_mesh_rom_64_words
#else
extern const v4_cell v4_mesh_rom_32[];
extern const unsigned v4_mesh_rom_32_words;
#define MESH_ROM v4_mesh_rom_32
#define MESH_ROM_WORDS v4_mesh_rom_32_words
#endif

/* The entry table, in its fixed order: entry i is at V4_ROM_BASE + i. */
#define ROM_MATH_NAME(i, routine, forth, effect) routine,
static const char *const rom_entries[] = {
    V4_ROM_MATH_ENTRIES(ROM_MATH_NAME)
    "(KEY)", "(TOKEN)", "(NUMBER)", "(FIND)", "(DEFINE)", "(OPCODE)",
    "(OP)", "(LIT)", "(BRANCH)", "(BRANCH>)", "(RESOLVE)", "(LABEL)", "(ROM)"
};
#undef ROM_MATH_NAME
#define ROM_ENTRIES (sizeof rom_entries / sizeof rom_entries[0])

static v4_exec_state rom_es;
static v4_heat       rom_h;

/* The address a payload calls for the routine `name`: its entry. */
static v4_cell rom_entry(const char *name)
{
    unsigned i;
    for (i = 0; i < ROM_ENTRIES; i++) if (strcmp(rom_entries[i], name) == 0) return V4_ROM_BASE + (v4_cell)i;
    printf("rom_harness: %s is not in the entry table\n", name);
    return -1;
}

/* Call the routine through its entry.  1 if it returned within `max_words`
 * instruction words; 0 if not, and the node is left where it got to, to be
 * fed and resumed. */
static int rom_call(v4_node *n, const char *name, long max_words)
{
    return v4_test_call(n, &rom_es, &rom_h, rom_entry(name), max_words) >= 0;
}

/* Go on with a call that had not returned.  1 if it now has. */
static int rom_resume(v4_node *n, long max_words)
{
    long words = 0;
    while (n->p != V4_TEST_HALT) {
        if (words++ >= max_words || n->stopped) return 0;
        (void)v4_exec_step_word(n, &rom_es, &rom_h);
    }
    return 1;
}

/* 1 if P is inside the ROM's word `name`: at or after it, and before the
 * next word the ROM has. */
static int rom_in(const v4_node *n, const char *name)
{
    FILE *f = fopen(V4_ROM_SYM, "r");
    char sym[80];
    long addr, start = -1, next = -1;
    if (!f) { printf("rom_harness: cannot read %s\n", V4_ROM_SYM); return 0; }
    while (fscanf(f, "%79s %ld", sym, &addr) == 2)
        if (strcmp(sym, name) == 0) start = addr;
    rewind(f);
    while (fscanf(f, "%79s %ld", sym, &addr) == 2)
        if (start >= 0 && addr > start && (next < 0 || addr < next)) next = addr;
    fclose(f);
    if (start < 0) return 0;
    if (next < 0) next = (long)V4_ROM_BASE + (long)ROM_IMAGE_WORDS;
    return (long)n->p >= start && (long)n->p < next;
}

static char *rom_system_text(size_t *len);
static int rom_build_system(v4_node *n, long *words);

/* Reset `n`, attach the ROM and the console's receive registers. */
static void rom_boot(v4_node *n)
{
    (void)rom_build_system;
    (void)host_load;                         /* host_map.h's loader is not used here */
    (void)host_branch_slots;
    (void)rom_call;                          /* not every test uses every helper */
    (void)rom_resume;
    (void)rom_in;
    v4_node_reset(n);
    v4_exec_reset(&rom_es);
    v4_heat_reset(&rom_h);
    v4_node_rom_attach(n, ROM_IMAGE, ROM_IMAGE_WORDS);
    v4_node_console_input_attach(n, CONSOLE_RX, CONSOLE_ST);
}

/* THE SYSTEM, AS THE MACHINE BUILDS IT (MACHINE.md section 6, step 1).  The
 * system's source, capsules/v4/sys (V4_SYS_DIR): the map, v4/sys_files.h and
 * the end, each followed by a new line and V4_ROM_BLOB_END, then EOT -- what v4/system/boot.c
 * feeds the console.  rom_system_text gives it whole, *len its length;
 * rom_build_system has `n`, booted with its ROM, assemble it, and runs it to
 * its start: 1 if it started, with *words the instruction words it took. */
#define ROM_SYS_FILE(file) #file,
static const char *const rom_system_files[] = { V4_SYS_FILES(ROM_SYS_FILE) };
#undef ROM_SYS_FILE
#define ROM_SYS_FILES ((unsigned)(sizeof rom_system_files / sizeof rom_system_files[0]))

static char *rom_system_text(size_t *len)
{
    size_t total = 0, cap = 1u << 20;
    char *text = malloc(cap);
    unsigned i;
    if (!text) return NULL;
    for (i = 0; i < ROM_SYS_FILES + 2u; i++) {
        char path[512];
        FILE *f;
        long n;
        if (i == 0) snprintf(path, sizeof path, "%s/map-%d.f18", V4_SYS_DIR, V4_CELL_BITS);
        else if (i <= ROM_SYS_FILES) snprintf(path, sizeof path, "%s/%s.f18", V4_SYS_DIR, rom_system_files[i - 1]);
        else snprintf(path, sizeof path, "%s/end.f18", V4_SYS_DIR);
        f = fopen(path, "rb");
        if (!f) { printf("    cannot read %s\n", path); free(text); return NULL; }
        fseek(f, 0, SEEK_END); n = ftell(f); fseek(f, 0, SEEK_SET);
        if (n < 0 || total + (size_t)n + 3 > cap || fread(text + total, 1, (size_t)n, f) != (size_t)n) {
            fclose(f); free(text); return NULL;
        }
        fclose(f);
        total += (size_t)n;
        text[total++] = '\n';                      /* a blob that does not end with a new line still ends a token */
        text[total++] = V4_ROM_BLOB_END;           /* and the blob ends, as a file ends for text.c */
    }
    text[total++] = 4;                               /* EOT */
    *len = total;
    return text;
}

static int rom_build_system(v4_node *n, long *words)
{
    size_t total, fed = 0;
    char *text = rom_system_text(&total);
    long w = 0;
    if (!text) return 0;
    rom_boot(n);
    v4_node_stack_regs_attach(n, DSTACK_REG, RSTACK_REG);
    n->p = V4_ROM_BASE + (v4_cell)V4_ROM_START;      /* (ROM): where the machine starts */
    while (n->p >= V4_ROM_BASE && w < 400000000L && !n->stopped) {
        if (fed < total && n->input_pos == n->input_len) fed += v4_node_console_feed(n, text + fed, (unsigned)(total - fed));
        (void)v4_exec_step_word(n, &rom_es, &rom_h);
        w++;
        if (w % 1000 == 0 && n->mem[ROM_FAILED] != 0) break;
    }
    free(text);
    n->input_pos = n->input_len = 0;                 /* what was not read is the source's: boot.c takes it back */
    if (words) *words = w;
    return n->p < V4_ROM_BASE && n->mem[ROM_FAILED] == 0;
}

#endif /* V4_TESTS_ROM_HARNESS_H */