#define FRONTEND_IMPLEMENTATION
#include "../frontend.h"
#include "token.h"

#define ROUND_IDX(idx) ((idx) % tokbuf->cap)

tok_t* pop_tok(tok_buf_t* tokbuf) {
    if (tokbuf->size == 0) {
        error("no token to pop");
        return NULL;
    }
    int idx = tokbuf->cur;
    tokbuf->cur = ROUND_IDX(idx + 1);
    tokbuf->size -= 1;
    return tokbuf->buf + idx;
}

void flush_peek_tok(tok_buf_t* tokbuf) {
    tokbuf->peek = tokbuf->cur;
}

void init_tokbuf(tok_buf_t *tokbuf, void *stream, get_tokbuf_func gettok) {
    tokbuf->cur = 0;
    tokbuf->end = 0;
    tokbuf->peek = 0;
    tokbuf->size = 0;
    tokbuf->stream = stream;
    tokbuf->gettok = gettok;
    tokbuf->buf = NULL;
    tokbuf->cap = 0;
}

tok_t *peek_tok(tok_buf_t *tokbuf) {
    int idx = tokbuf->peek;
    tokbuf->peek = ROUND_IDX(idx + 1);
    if (tokbuf->size >= tokbuf->cap) {
        error("peek too deep, outof array size");
    }
    if (idx == tokbuf->end) {
        if (tokbuf->size == tokbuf->cap) {
            error("peek_tok buffer overflow");
        }
        if (tokbuf->gettok == NULL) {
            error("peek_tok can not got tok");
        }
        tokbuf->gettok(tokbuf->stream, &(tokbuf->buf[idx]));
        tokbuf->size++;
        tokbuf->end = tokbuf->peek;
    }

    return &(tokbuf->buf[idx]);
}

tok_type_t peek_tok_type(tok_buf_t* tokbuf) {
    return peek_tok(tokbuf)->type;
}

int expect_pop_tok(tok_buf_t* tokbuf, tok_type_t type) {
    flush_peek_tok(tokbuf);
    tok_t* tok = peek_tok(tokbuf);
    if (tok->type != type) {
        error("expected tok: %s, got %s", get_tok_name(type), get_tok_name(tok->type));
    } else {
        pop_tok(tokbuf);
    }
    return 0;
}

// 生成字符串映射（根据需求选择#str或#name）
static const char* token_strings[] = {
    // 普通token使用#str
    #define X(str, tok) [tok] = #str,
    TOKEN_TABLE
    #undef X
    
    // 关键字使用#name
    #define X(name, std, tok) [tok] = #name,
    KEYWORD_TABLE
    #undef X
};

const char* get_tok_name(tok_type_t type) {
    return token_strings[type];
}