#include "from.h"
#include "stmt.h"
#include "cgen.h"
#include "qbe.h"
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

static int loadvar(const struct from_it *st, struct cgen *c)
{
    const struct stentry *e = st->u.e;
    size_t sz = e->t->sz;
    const char *tmp = cgen_tmp(sz);

    printf("%%%s =%s load%s ", tmp, cgen_sz(sz), cgen_load(e->t));
    cgen_printvar(c->fn, e);
    putchar('\n');
    return 0;
}

/* TODO: de-duplicate function */
static unsigned long long tonum(const char *s)
{
    unsigned long long v;
    char *end;

    errno = 0;
    v = strtoull(s, &end, 0);

    if (*s == '-' || errno || *end)
        return strtoll(s, NULL, 0);

    return v;
}

static int loadval(const struct from *fr, struct cgen *c)
{
    const struct stentry *dst = fr->var;
    const struct from_it *st = &fr->start;
    unsigned long long v = tonum(st->u.tk->s);

    printf("store%s %llu, ", cgen_sz(dst->t->sz), v);
    cgen_printvar(c->fn, dst);
    putchar('\n');
    return 0;
}

static int endvar(const struct from *fr, struct cgen *c)
{
    fprintf(stderr, "%s: TODO\n", __func__);
    return -1;
}

static int endval(const struct from *fr, struct cgen *c)
{
    const struct stentry *src = fr->var;
    size_t sz = src->t->sz;
    const char *tmp = cgen_tmp(sz);
    const struct from_it *end = &fr->end;
    const struct tk *tk = end->u.tk;
    int neg = *tk->s == '-';
    size_t bl = fr->block_i;

    printf("%%%s =%s load%s ", tmp, cgen_sz(sz), cgen_load(src->t));
    cgen_printvar(c->fn, src);
    putchar('\n');
    printf("%%%s =%s c", tmp, cgen_sz(sz));
    fputs(neg ? "sge" : "uge", stdout);
    printf("%s ", cgen_sz(sz));
    printf("%%%s, %s\n", tmp, tk->s);
    printf("jnz %%%s, @__end%zu, @__blockbody%zu\n", tmp, bl, bl);
    printf("@__blockbody%zu\n", bl);
    return 0;
}

static int from_var(const struct from *fr, struct cgen *c)
{
    const struct from_it *st = &fr->start;

    switch (st->type)
    {
    case FR_VAR:
        if (loadvar(st, c))
            return -1;
        break;

    case FR_VAL:
        if (loadval(fr, c))
            return -1;
        break;
    }

    printf("@__block%zu\n", fr->block_i);

    switch (fr->end.type)
    {
    case FR_VAR:
        if (endvar(fr, c))
            return -1;
        break;

    case FR_VAL:
        if (endval(fr, c))
            return -1;
        break;
    }

    return 0;
}

int from_end(const struct stmt *s, struct cgen *c)
{
    const struct from *fr = &s->u.from;
    const struct stentry *src = fr->var;
    const struct type *t = src->t;
    size_t sz = t->sz;
    const char *tmp = cgen_tmp(sz);
    const struct fn *fn = c->fn;

    printf("%%%s =%s load%s ", tmp, cgen_sz(sz), cgen_load(t));
    cgen_printvar(fn, src);
    putchar('\n');
    printf("%%%s =%s add %%%s, 1\n", tmp, cgen_sz(sz), tmp);
    printf("store%s %%%s, ", cgen_sz(sz), tmp);
    cgen_printvar(fn, src);
    putchar('\n');
    printf("jmp @__block%zu\n", fr->block_i);
    return 0;
}

int qbe_from(const struct from *fr, struct cgen *c)
{
    return from_var(fr, c);
}