#include "cgen.h"
#include "fn.h"
#include "lex.h"
#include "lit.h"
#include "parse.h"
#include "storage.h"
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

void cgen_free(struct cgen *c)
{
}

const char *cgen_sz(const size_t sz)
{
    switch (sz)
    {
        case 1:
            return "b";
        case 2:
            return "h";
        case 4:
            return "w";
        case 8:
            return "l";
        default:
            break;
    }

    return NULL;
}

const char *cgen_type(const struct type *t)
{
    switch (t->sz)
    {
    case 1:
        return t->sign ? "b" : "ub";
    case 2:
        return t->sign ? "h" : "uh";
    case 4:
        return t->sign ? "w" : "uw";
    case 8:
        return t->sign ? "l" : "ul";

    default:
        break;
    }

    return NULL;
}

const char *cgen_abity(const struct type *t)
{
    switch (t->sz)
    {
    case 1:
        return t->sign ? "b" : "ub";
    case 2:
        return t->sign ? "h" : "uh";
    case 4:
        return "w";
    case 8:
        return "l";

    default:
        break;
    }

    return NULL;
}

const char *cgen_load(const struct type *t)
{
    switch (t->sz)
    {
    case 1:
        return t->sign ? "sb" : "ub";
    case 2:
        return t->sign ? "sh" : "uh";
    case 4:
        return t->sign ? "sw" : "uw";
    case 8:
        return "l";

    default:
        break;
    }

    return NULL;
}

int cgen_param(const struct fn *fn, const struct stentry *e)
{
    const struct pr *pr = fn->pr;
    const char *name = e->tk->s;

    for (size_t i = 0; i < pr->nparams; i++)
        if (!strcmp(pr->params[i].tk->s, name))
            return 1;

    return 0;
}

int cgen_global(const struct fn *fn, const struct stentry *e)
{
    const struct storage *ws = fn->ws, *gl = fn->gl;
    const struct pr *pr = fn->pr;
    const struct param *ret = pr->ret;
    const char *name = e->tk->s;

    /* A variable is only global if it is defined inside the global
     * variables section ("gl"), or if it is not listed on the working
     * storage section ("ws"), as a function parameter or a return value. */

    if (gl)
        for (size_t i = 0; i < gl->nentries; i++)
            if (!strcmp(gl->entries[i].tk->s, name))
                return 1;

    if (cgen_param(fn, e))
        return 0;

    if (ret && !strcmp(ret->tk->s, name))
        return 0;

    if (ws)
        for (size_t i = 0; i < ws->nentries; i++)
            if (!strcmp(ws->entries[i].tk->s, name))
                return 0;

    return 1;
}

static void pushfmt(const char *type, const char *fmt)
{
    printf("data $____fmt%s = { b \"%s\" , b 0 }\n", type, fmt);
}

int cgen(const struct ast *ast, struct cgen *c)
{
    /* generate literals to use with printf(3) */
    pushfmt("b", "%hhd");
    pushfmt("h", "%hd");
    pushfmt("w", "%d");
    pushfmt("l", "%ld");
    pushfmt("ub", "%hhu");
    pushfmt("uh", "%hu");
    pushfmt("uw", "%u");
    pushfmt("ul", "%lu");
    pushfmt("bx", "%#hhx");
    pushfmt("hx", "%#hx");
    pushfmt("wx", "%#x");
    pushfmt("lx", "%#lx");

    for (const struct lit *l = ast->lits; l; l = l->next)
        if (lit_cgen(l))
            return-1;

    for (size_t i = 0; i < ast->nfns; i++)
        if (fn_cgen((c->fn = &ast->fns[i]), c))
            return -1;

    return 0;
}