#include "sym.h"
#include "errloc.h"
#include "fn.h"
#include "lex.h"
#include "parse.h"
#include "prv.h"
#include "storage.h"
#include "type.h"
#include <stdio.h>
#include <stdlib.h>

static int addr(const struct lex *, struct prv *);
static int cnt(const struct lex *, struct prv *);
static int off(const struct lex *, struct prv *);
static int szof(const struct lex *, struct prv *);
static int idof(const struct lex *, struct prv *);
static int numof(const struct lex *, struct prv *);
static int cast(const struct lex *, struct prv *);
static int to(const struct lex *, struct prv *);
static int lit(const struct lex *, struct prv *);
static int num(const struct lex *, struct prv *);
static int id(const struct lex *, struct prv *);
static int push_to(struct prv *);

static const struct seq seqs[] =
{
    {(struct step[]){{ID, "address"}, {ID, "of"}, {0}}, .fn = addr},
    {(struct step[]){{ID, "contents"}, {ID, "of"}, {0}}, .fn = cnt},
    {(struct step[]){{ID, "offset"}, {ID, "of"}, {0}}, .fn = off},
    {(struct step[]){{ID, "size"}, {ID, "of"}, {0}}, .fn = szof},
    {(struct step[]){{ID, "cast"}, {0}}, .fn = cast},
    {(struct step[]){{ID}, {ID, "of"}, {0}}, .fn = idof},
    {(struct step[]){{NUM}, {ID, "of"}, {0}}, .fn = numof},
    {(struct step[]){{LIT}, {0}}, .fn = lit},
    {(struct step[]){{NUM}, {0}}, .fn = num},
    {(struct step[]){{ID}, {0}}, .fn = id},
    {0}
};

static const struct seq cast_seqs[] =
{
    {(struct step[]){{ID, "to"}, {0}}, .fn = to},
    {0}
};

static void queue(struct prv *p, struct sym *s)
{
    struct sym *ss = p->s;

    if (!ss)
        p->s = s;
    else
    {
        while (ss->child)
            ss = ss->child;

        ss->child = s;
        s->parent = ss;
    }

    reset(p);
}

static int pushsym(struct prv *p, enum symtype t)
{
    struct sym *s = malloc(sizeof *s);

    if (!s)
    {
        perror("malloc(3)");
        return -1;
    }

    *s = (struct sym){.type = t, .tk = p->stk};
    queue(p, s);
    return 0;
}

static int addr(const struct lex *l, struct prv *p)
{
    return pushsym(p, SYM_ADDR);
}

static int cnt(const struct lex *l, struct prv *p)
{
    return pushsym(p, SYM_CNT);
}

static int off(const struct lex *l, struct prv *p)
{
    return pushsym(p, SYM_OFF);
}

static int szof(const struct lex *l, struct prv *p)
{
    return pushsym(p, SYM_SZ);
}

static void insert(struct fn *fn, struct sym *s)
{
    struct sym *ss = fn->syms;

    while (ss && ss->next)
        ss = ss->next;

    if (!ss)
        fn->syms = s;
    else
        ss->next = s;
}

static int symbol(const struct sym *s)
{
    switch (s->type)
    {
    case SYM_ID:
    case SYM_TMP:
    case SYM_LIT:
    case SYM_NUM:
        return 1;

    case SYM_CAST:
    case SYM_ADDR:
    case SYM_SZ:
    case SYM_CNT:
    case SYM_OFF:
        break;
    }

    return 0;
}

static struct sym *getsym(struct sym *s)
{
    for (struct sym *ss = s; ss; ss = ss->child)
        if (symbol(ss))
            return ss;

    return NULL;
}

static int idof(const struct lex *l, struct prv *p)
{
    fprintf(stderr, "%s: TODO\n", __func__);
    reset(p);
    return -1;
}

static int numof(const struct lex *l, struct prv *p)
{
    fprintf(stderr, "%s: TODO\n", __func__);
    reset(p);
    return -1;
}

static struct sym *inner(struct sym *s)
{
    struct sym *ret = NULL;

    for (; s; s = s->child)
        if (s->type == SYM_CAST && !s->u.t)
            ret = s;

    return ret;
}

static struct sym *resolve(const struct sym *s)
{
    fprintf(stderr, "%s: TODO\n", __func__);
    return NULL;
}

static int run(const struct lex *l, struct prv *p)
{
    struct fn *fn = fn_cur(p);
    struct sym *s = p->s;

    insert(fn, s);
    p->s = NULL;

    if (getsym(s))
        return p->sym(l, p, s);

    errloc(p->stk - 1, "expected identifier, literal or number");
    return -1;
}

static int totype(const struct lex *l, struct prv *p, const struct type *t)
{
    struct sym *s = inner(p->s);

    if (!s || s->u.t)
    {
        errloc(p->tk - 1, "incomplete cast");
        return -1;
    }

    s->u.t = t;

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

    return !inner(p->s) && getsym(p->s) ? run(l, p) : 0;
}

static int to(const struct lex *l, struct prv *p)
{
    return type(l, p, totype);
}

static int endcast(const struct lex *l, struct prv *p)
{
    struct sym *s = inner(p->s);

    if (!p->cast--)
    {
        errloc(p->tk - 1, "incomplete cast");
        return -1;
    }
    else if (s)
    {
        if (lex_eof(l, p->tk))
        {
            errloc(p->tk - 1, "incomplete cast");
            return -1;
        }

        return push_to(p);
    }

    return 0;
}

static int cast(const struct lex *l, struct prv *p)
{
    p->cast++;
    return pushsym(p, SYM_CAST);
}

static int push_to(struct prv *p)
{
    struct pos init =
    {
        .name = __func__,
        .seq = cast_seqs,
        .end = endcast
    };

    return push(&init, p);
}

static int lit(const struct lex *l, struct prv *p)
{
    struct sym *cs = inner(p->s);

    if (pushsym(p, SYM_LIT))
        return -1;

    return cs ? push_to(p) : run(l, p);
}

static int num(const struct lex *l, struct prv *p)
{
    fprintf(stderr, "%s: TODO\n", __func__);
    reset(p);
    return -1;
}

static int id(const struct lex *l, struct prv *p)
{
    struct sym *cs = inner(p->s);

    if (pushsym(p, SYM_ID))
        return -1;
    else if (cs)
        return push_to(p);

    p->stk = p->tk;
    return run(l, p);
}

void sym_free(struct sym *s)
{
    struct sym *ss = s;

    while (ss)
    {
        struct sym *child = ss->child;

        free(ss);
        ss = child;
    }
}

int sym_lval(const struct sym *s)
{
    int ret = 1;

    while (s)
    {
        switch (s->type)
        {
        case SYM_OFF:
        case SYM_SZ:
        case SYM_LIT:
        case SYM_NUM:
        case SYM_TMP:
            ret = 0;
            break;

        case SYM_ADDR:
            if (!s->parent || s->parent->type != SYM_CNT)
                ret = 0;
        case SYM_ID:
        case SYM_CNT:
        case SYM_CAST:
            break;
        }

        s = s->child;
    }

    return ret;
}

static int endsym(const struct lex *l, struct prv *p)
{
    return p->s ? run(l, p) : 0;
}

static int invalid(const struct tk *tk, const struct type *a,
    const struct type *b)
{
    static int t[BUILTIN + 1][BUILTIN + 1] =
    {
        /*              U  S  C  P  T PTR ARY BUILTIN */
        /* U        */ {1, 0, 0, 0, 0, 0,  0,  0},
        /* S        */ {0, 1, 0, 0, 0, 0,  0,  0},
        /* C        */ {0, 0, 1, 0, 0, 0,  0,  0},
        /* P        */ {0, 0, 0, 1, 0, 1,  0,  0},
        /* T        */ {0, 0, 0, 0, 1, 0,  0,  0},
        /* PTR      */ {0, 0, 0, 0, 0, 1,  1,  0},
        /* ARY      */ {0, 0, 0, 0, 0, 0,  1,  0},
        /* BUILTIN  */ {0, 0, 0, 0, 0, 0,  0,  1}
    };

    int valid = t[a->type][b->type];

    if (!valid)
    {
        char *s1 = type_name(b), *s2 = type_name(a);

        if (s1 && s2)
            errloc(tk, "cannot convert \"%s\" to \"%s\"", s1, s2);

        free(s1);
        free(s2);
    }

    return !valid;
}

static const struct type *genlittype(struct prv *p)
{
    const struct fn *fn = fn_cur(p);
    const char *tr = triplet(p);
    const struct type *byte = type_find(fn, tr, "char");
    struct type *bytedup = NULL, *t = NULL;

    if (!byte)
        return NULL;
    else if (!(bytedup = malloc(sizeof *bytedup))
        || !(t = malloc(sizeof *t)))
    {
        perror("malloc(3)");
        goto failure;
    }

    *bytedup = *byte;
    *t = (struct type)
    {
        .type = ARY,
        .u.ary.etc = 1,
        .child = bytedup
    };

    return p->ast->littype = type_insert(p, t);

failure:
    free(t);
    free(bytedup);
    return NULL;
}

static const struct type *littype(struct prv *p)
{
    const struct type *t = p->ast->littype;

    return t ? t : genlittype(p);
}

const struct type *sym_type(struct prv *p, const struct sym *s)
{
    const struct fn *fn = fn_cur(p);
    const struct type *ret = NULL;

    for (; s; s = s->child)
    {
        const struct tk *tk = s->tk;

        switch (s->type)
        {
        case SYM_CAST:
            if (!ret)
                ret = s->u.t;
            else if (invalid(tk, ret, s->u.t))
                return NULL;

            break;

        case SYM_ID:
        {
            const struct stentry *e = fn_var(fn, tk);
            const char *tr = triplet(p);
            const struct type *t;

            if (!e && !(t = type_ufind(fn, tr, tk->s)))
                return NULL;
            else if (e)
                t = e->t;

            if (!ret)
                ret = t;
            else if (invalid(tk, ret, t))
                return NULL;
        }
            break;

        case SYM_LIT:
        {
            const struct type *lt = littype(p);

            if (!ret)
                ret = lt;
            else if (invalid(tk, ret, lt))
                return NULL;
        }
            break;

        case SYM_ADDR:
        case SYM_TMP:
        case SYM_NUM:
        case SYM_SZ:
        case SYM_CNT:
        case SYM_OFF:
            break;
        }
    }

    return ret;
}

int sym_rval(const struct sym *s)
{
    return !sym_lval(s);
}

int sym(struct prv *p, sym_fn fn)
{
    struct pos init =
    {
        .name = __func__,
        .seq = seqs,
        .end = endsym
    };

    p->stk = p->tk;
    p->sym = fn;
    return push(&init, p);
}