#include "set.h"
#include "cgen.h"
#include "errloc.h"
#include "fn.h"
#include "lex.h"
#include "parse.h"
#include "prv.h"
#include "stmt.h"
#include "storage.h"
#include "type.h"
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

static int mv(const struct lex *l, struct prv *p);
static int maddr(const struct lex *l, struct prv *p);
static int msz(const struct lex *l, struct prv *p);
static int mimb(const struct lex *l, struct prv *p);

static const struct seq seqs[] =
{
    /* size of elementary data types */
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ID, "void"},
        {0}}, .fn = msz},
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ID, "byte"},
        {0}}, .fn = msz},
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ID, "halfword"},
        {0}}, .fn = msz},
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ID, "word"},
        {0}}, .fn = msz},
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ID, "long"},
        {0}}, .fn = msz},
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ID, "ubyte"},
        {0}}, .fn = msz},
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ID, "uhalfword"},
        {0}}, .fn = msz},
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ID, "uword"},
        {0}}, .fn = msz},
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ID, "ulong"},
        {0}}, .fn = msz},

    /* address of variable */
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "address"},
        {ID, "of"},
        {ID},
        {0}}, .fn = maddr},

    /* size of variable or type alias */
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ID, "size"},
        {ID, "of"},
        {ANY},
        {0}}, .fn = msz},

    /* array index or aggregate member */
    {(struct step[]){
        {ID, NULL, 1},
        {ID, "to"},
        {ANY},
        {ID, "of"},
        {ID},
        {0}}, .fn = mimb},

    /* simple set */
    {(struct step[]){{ID, NULL, 1}, {ID, "to"}, {ANY}, {0}}, .fn = mv},
    {0}
};

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 dst(const struct lex *l, const struct tk *tk, struct set *s,
    struct prv *p)
{
    const struct stentry *e = fn_var(fn_cur(p), tk);
    size_t n = s->ndsts + 1;
    struct setdst *dsts;

    if (!e)
    {
        errloc(tk, "undefined reference to \"%s\"", tk->s);
        return -1;
    }
    else if (!(dsts = realloc(s->dsts, n * sizeof *dsts)))
    {
        perror("realloc(3)");
        return -1;
    }

    s->dsts = dsts;
    s->dsts[s->ndsts++] = (struct setdst){.entry = e};
    return 0;
}

static int checkzero(const struct tk *tk, const struct set *s,
    unsigned long long v)
{
    if (!s->srcv)
        return 0;

    for (size_t i = 0; i < s->ndsts; i++)
    {
        const struct stentry *dst = s->dsts[i].entry;

        if (dst->t->type != BUILTIN)
        {
            errloc(tk, "destination \"%s\" cannot be set to \"%s\"",
                dst->tk->s, tk->s);
            return -1;
        }
    }

    return 0;
}


static int checkcompat(const struct tk *tk, const struct set *s)
{
    for (size_t i = 0; i < s->ndsts; i++)
    {
        const struct stentry *dst = s->dsts[i].entry;
        const struct type *st = s->src->t, *dt = dst->t;

        /* TODO: integer promotions */
        if (st->type != dt->type
            || st->sz != dt->sz
            || st->sign != dt->sign)
        {
            errloc(tk, "destination \"%s\" cannot be set to \"%s\"",
                dst->tk->s, tk->s);
            return -1;
        }
    }

    return 0;
}

static int mv(const struct lex *l, struct prv *p)
{
    const struct tk *tk = p->stk;
    const struct stentry *e;
    struct stmt *stmt = stmt_cur(p);
    struct set *s = &stmt->u.set;

    while (!lex_eof(l, tk) && !kw((tk)->s))
        if (dst(l, tk++, s, p))
            return -1;

    /* skip "to" */
    tk++;

    if (tk->type == LIT)
    {
        /* this can only be applied to arrays of/pointers to chars */
        fprintf(stderr, "%s: TODO\n", __func__);
        return -1;
    }
    else if (tk->type == NUM)
    {
        s->type = SET_VAL;
        s->srcv = tonum(tk->s);

        if (checkzero(tk, s, s->srcv))
            return -1;
    }
    else if (tk->type == ID)
    {
        const struct fn *fn = fn_cur(p);
        const struct type *t = type_find(fn, tk->s);

        if (t)
        {
            if (t->type != C)
            {
                errloc(tk, "type \"%s\" not a constant", tk->s);
                return -1;
            }

            s->type = SET_VAL;
            s->srcv = t->u.c.v;

            if (checkzero(tk, s, s->srcv))
                return -1;
        }
        else if ((e = fn_var(fn_cur(p), tk)))
        {
            s->type = SET_VAR;
            s->src = e;

            if (checkcompat(tk, s))
                return -1;
        }
        else
        {
            errloc(tk, "undefined reference to \"%s\"", tk->s);
            return -1;
        }
    }

    fputs("\t\tadding set ", stderr);

    for (size_t i = 0; i < s->ndsts; i++)
        fprintf(stderr, "%s ", s->dsts[i].entry->tk->s);

    fprintf(stderr, "to %s\n", tk->s);

    if (pop(l, p))
        return -1;

    p->stk = ++tk;
    return 1;
}

static int maddr(const struct lex *l, struct prv *p)
{
    const struct tk *tk = p->stk;
    struct stmt *stmt = stmt_cur(p);
    struct set *s = &stmt->u.set;
    const struct stentry *e;

    while (!lex_eof(l, tk) && !kw((tk)->s))
    {
        const struct stentry *e = fn_var(fn_cur(p), tk);

        if (e && e->t->type != PTR)
        {
            errloc(tk, "destination \"%s\" not a pointer", tk->s);
            return -1;
        }
        else if (dst(l, tk++, s, p))
            return -1;
    }

    /* skip "to address of" */
    tk += 3;

    if (!(e = fn_var(fn_cur(p), tk)))
    {
        errloc(tk, "undefined reference to \"%s\"", tk->s);
        return -1;
    }
    else if (pop(l, p))
        return -1;

    s->type = SET_ADDR;
    s->src = e;
    p->stk = ++tk;
    fputs("\t\tadding set ", stderr);

    for (size_t i = 0; i < s->ndsts; i++)
        fprintf(stderr, "%s ", s->dsts[i].entry->tk->s);

    fprintf(stderr, "to address of %s\n", s->src->tk->s);
    return 1;
}

static int msz(const struct lex *l, struct prv *p)
{
    const struct tk *tk = p->stk;
    const struct stentry *e;
    struct stmt *stmt = stmt_cur(p);
    struct set *s = &stmt->u.set;
    const struct fn *fn = fn_cur(p);
    const struct type *t;

    while (!lex_eof(l, tk) && !kw(tk->s))
    {
        const struct stentry *e = fn_var(fn_cur(p), tk);

        if (e && e->t->type != BUILTIN)
        {
            errloc(tk, "destination \"%s\" not an integer", tk->s);
            return -1;
        }
        else if (dst(l, tk++, s, p))
            return -1;
    }

    /* skip "to size of" */
    tk += 3;

    if (tk->type == NUM)
    {
        errloc(tk, "cannot compute size of a number");
        return -1;
    }
    else if (tk->type == LIT)
        s->srcv = strlen(tk->s) + 1;
    else if ((t = type_find(fn, tk->s)))
    {
        if (!t->sz)
        {
            errloc(tk, "type \"%s\" has no size", tk->s);
            return-1;
        }

        s->srcv = t->sz;
    }
    else if ((e = fn_var(fn, tk)))
        s->srcv = e->t->sz;
    else
        return-1;

    if (pop(l, p))
        return -1;

    s->type = SET_VAL;
    p->stk = ++tk;
    fputs("\t\tadding set ", stderr);

    for (size_t i = 0; i < s->ndsts; i++)
        fprintf(stderr, "%s ", s->dsts[i].entry->tk->s);

    fprintf(stderr, "size=%llu\n", s->srcv);
    return 1;
}

static int mimb(const struct lex *l, struct prv *p)
{
    const struct tk *tk = p->stk;
    const struct fn *fn = fn_cur(p);
    struct stmt *stmt = stmt_cur(p);
    struct set *s = &stmt->u.set;

    while (!lex_eof(l, tk) && !kw((tk)->s))
        if (dst(l, tk++, s, p))
            return -1;

    /* skip "to" */
    tk++;

    fputs("\t\tadding set ", stderr);

    for (size_t i = 0; i < s->ndsts; i++)
        fprintf(stderr, "%s ", s->dsts[i].entry->tk->s);

    if (tk->type == LIT)
    {
        errloc(tk, "unexpected literal \"%s\"", tk->s);
        return -1;
    }
    else if (tk->type == ID && !(s->off = fn_var(fn, tk)))
    {
        errloc(tk, "undefined reference to \"%s\"", tk->s);
        return -1;
    }
    else if (tk->type == NUM)
        s->srcv = tonum(tk->s);

    fprintf(stderr, "to [%s] ", tk->s);

    /* skip index and "of" */
    tk += 2;

    if (!(s->src = fn_var(fn, tk)))
    {
        errloc(tk, "undefined reference to \"%s\"", tk->s);
        return -1;
    }
    else if (pop(l, p))
        return -1;

    fprintf(stderr, " of %s\n", tk->s);
    s->type = SET_IMB;
    p->stk = ++tk;
    return 1;
}

void set_free(struct set *m)
{
    if (m)
        free(m->dsts);
}

static int cg_val(const struct set *s, const struct stentry *dst,
    struct cgen *c)
{
    const char *szstr = cgen_sz(dst->t->sz), *ab = cgen_abity(dst->t);
    const struct fn *fn = c->fn;

    if (ab)
    {
        printf("store%s %llu, ", szstr, s->srcv);
        cgen_printvar(fn, dst);
    }
    else
    {
        fputs("%r =l call $memset(l ", stdout);
        cgen_printvar(fn, dst);
        printf(", w 0, l %zu)", dst->t->sz);
    }

    putchar('\n');
    return 0;
}

static int cg_addr(const struct set *s, const struct stentry *dst,
    struct cgen *c)
{
    printf("store%s ", cgen_sz(dst->t->sz));
    cgen_printvar(c->fn, s->src);
    fputs(", ", stdout);
    cgen_printvar(c->fn, dst);
    putchar('\n');
    return 0;
}

static int cg_var(const struct set *s, const struct stentry *dst,
    struct cgen *c)
{
    const struct stentry *src = s->src;
    const char *tmp = cgen_tmp(src->t->sz);

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

static int cg_imb(const struct set *s, const struct stentry *e, struct cgen *c)
{
    fprintf(stderr, "%s: TODO\n", __func__);
    return -1;
}

int set_cgen(const struct set *s, struct cgen *c)
{
    for (size_t i = 0; i < s->ndsts; i++)
    {
        const struct stentry *dst = s->dsts[i].entry;

        static int (*const f[])(const struct set *, const struct stentry *,
            struct cgen *) =
        {
            [SET_VAL] = cg_val,
            [SET_ADDR] = cg_addr,
            [SET_VAR] = cg_var,
            [SET_IMB] = cg_imb
        };

        if (f[s->type](s, dst, c))
            return -1;
    }

    return 0;
}

int set(const struct lex *l, struct prv *p)
{
    const struct tk *next = p->tk;
    const char *ns;
    struct fn *fn = fn_cur(p);
    size_t n = fn->nstmts + 1;
    struct stmt *stmts;

    if (lex_eof(l, next))
    {
        errloc(next - 1, "incomplete set statement");
        return -1;
    }
    else if (kw((ns = next->s)))
    {
        errloc(next, "incomplete set statement");
        return -1;
    }
    else if (!(stmts = realloc(fn->stmts, n * sizeof *stmts)))
    {
        perror("realloc(3)");
        return -1;
    }

    fn->stmts = stmts;
    fn->stmts[fn->nstmts++] = (struct stmt){.type = SET};

    struct pos init =
    {
        .seq = seqs,
        .stseq = seqs,
        .step = seqs->steps
    };

    if (push(&init, p))
        return -1;

    p->stk = p->tk;
    return 1;
}