#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <ctype.h>

// TODO: lr parser is bad for debugging

#define INPUT_CAP 4096
#define ARENA_CAP 4096

#define ARENA_IMPLEMENTATION
#include "util/arena.h"

static char buf[ARENA_CAP];
static struct arena_ctx global_arena;
static void *xalloc(size_t sz) {
    void *addr = arena_allocate(&global_arena, sz);
    if(!addr) {
        fprintf(stderr, "ERROR: Arena empty\n"); exit(1);
    }

    return addr;
}

// other things here
#include "util/list.h"
static inline struct list_head *list_new_head(struct list_head *head, struct list_head *new)
{
    if(head) list_add(new, head);
    return new;
}

#define list_new_head(head, new) (intptr_t)list_new_head((struct list_head *)head, (struct list_head *)new)

// generated
#include "bin/lbp.h"
#include "bin/lbp.c"

#include "util/dict.h"
static struct dict types_dict;
static struct string_token types_strings[] = {
    {"int", T_INT},
    {"enum", T_ENUM},
    {"struct", T_STRUCT},
    {"function", ST_FUNCTION},
    {"big", ST_BIG},
    {"little", ST_LITTLE},
    {"native", ST_NATIVE},
};
static size_t ntypes_strings = sizeof(types_strings)/sizeof(*types_strings);
static uint8_t dict_lowercase_char_to_bit[256] = {
    ['a'] = 2,  ['b'] = 3,  ['c'] = 4,  ['d'] = 5,  ['e'] = 6,  ['f'] = 7,
    ['g'] = 8,  ['h'] = 9,  ['i'] = 10, ['j'] = 11, ['k'] = 12, ['l'] = 13,
    ['m'] = 14, ['n'] = 15, ['o'] = 16, ['p'] = 17, ['q'] = 18, ['r'] = 19,
    ['s'] = 20, ['t'] = 21, ['u'] = 22, ['v'] = 23, ['w'] = 24, ['x'] = 25,
    ['y'] = 26, ['z'] = 27, [ 0 ] = 1,  [' '] = 1
};


#include "parts/toklist.h"
struct token {
    symbol s;
    intptr_t v;
};

#include "util/queue.h"
QUEUE_GENERATE(tokbuf, struct token, 16)

symbol token_sym(struct token *t) { return t->s; }
intptr_t token_val(struct token *t) { return t->v; }

static void print_token(struct token *t);
static char *next_token(char *str);

static char *input;

struct token *toklist_eat()
{
    static struct token t;
    tokbuf_dequeue(&t); // err not checked
    if(tokbuf_empty()) input = next_token(input);
    return &t;
}

struct token *toklist_peek() {
    static struct token t;
    tokbuf_peek(&t);   // err not checked
    return &t;
}

// #define _LR_PARSER_DEBUG
#include "lr-parser.c"

int main(void)
{
    static char input_buf[INPUT_CAP];
    if(fread(input_buf, INPUT_CAP, 1, stdin) == INPUT_CAP) {
        fprintf(stderr, "INPUT_CAP reached\n");
        return 1;
    }

    global_arena = ARENA_CTX_INIT(buf, ARENA_CAP);

    types_dict = DICT_INIT(types_strings, ntypes_strings, dict_lowercase_char_to_bit);
    dict_compile(&types_dict);

    input = next_token(input_buf);

    // while(1) {
    //     struct token *tok = toklist_eat();
    //     print_token(tok);
    //     if(token_sym(tok) == END_INPUT) break;
    // } return 0;

    intptr_t value;
    if(lr_parser(&value)) {
        fprintf(stderr, input);
        return 1;
    }

    fprintf(stderr, "OUTPUT: %jd\n", value);

    dict_free(&types_dict);
    return 0;
}

static void print_token(struct token *tok)
{
    printf("%s\n", symbol_to_str[token_sym(tok)]);
    if(token_sym(tok) == IDEN || token_sym(tok) == ATOM) printf("  %s\n", (char *)token_val(tok));
}

// STR UTIL

#define strdup(...) _strdup(__VA_ARGS__)
static inline char *_strdup(char *str)
{
    return memcpy(xalloc(strlen(str) + 1), str, strlen(str)+1);
}

static inline char *substring(char *str, size_t sub_end)
{
    static char sub[128];
    if(!str) return sub;

    if(sub_end+1 > sizeof(sub)) return NULL;

    sub[sub_end] = '\0';
    return memcpy(sub, str, sub_end);
}

static inline size_t tillch(char *str, size_t len, char ch)
{
    for(size_t i = 0; i < len; i++) if(str[i] == ch) return i;
    return len;
}

// LEXER

static inline int issep(char c)
{
    return isspace(c) || c == '\0' || c == '/' || c == ',' || c == ';' ||
        c == '.' || c == '(' || c == ')' || c == '{' || c == '}';
}

static inline int tillsep(char *str)
{
    size_t i = 0;
    while(!issep(str[i++]));
    return i-1;
}

static char *typelist_tokenize(char *str)
{
    size_t off = 0;
    while(!issep(str[off]) && str[off] != '-') off++;

    if(off > 0) {
        int s = dict_check(&types_dict, substring(str, off));
        if(s < 0) {
            fprintf(stderr, "ERROR: Unknown type or subtype %s\n", substring(NULL, 0));
            return NULL;
        }

        tokbuf_enqueue(&(struct token){.s = s, .v = s});
    }

    str += off;

    switch(str[0]) {
    case '-': return typelist_tokenize(str+1);
    case '(':
        while((str = next_token(str)))
            if(*(str-1)== ')') { // not really
                if(str[0] == '-') return typelist_tokenize(str+1);
                else return str;
            }
        return NULL;
    default: return str;
    }
}

static char *next_token(char *str)
{
    if(!str) return str;

    struct token tok = {0};
    size_t off = 0;
    char c0 = str[0];

    if(c0 == '\0') tok.s = END_INPUT;
    if(isspace(c0)) return next_token(str+1);
    else {
        off = tillsep(str);
        if(off == 0) { // sep
            switch(str[off++]) {
            case ',': tok.s = COMMA; break;
            case ';': tok.s = SEMICOL; break;
            case '.': tok.s = DOT; break;
            case '(': tok.s = LPAREN; break;
            case ')': tok.s = RPAREN; break;
            case '{': tok.s = LBRACE; break;
            case '}': tok.s = RBRACE; break;
            case '/':
                tok.s = TYPELIST_START; tokbuf_enqueue(&tok);
                if(!(str = typelist_tokenize(str+off))) goto fail;
                tok.s = TYPELIST_END; tokbuf_enqueue(&tok);
                return str;
            default: break;
            }
        } else if(c0 >= '0' && c0 <= '9') { // num
            tok.s = NUM;
            tok.v = (intptr_t)atoi(substring(str, off)); // not really
        } else { // iden or atom (possibly with fields)
            int hasfield = 0;
            size_t sub_off;

            do {
                sub_off = tillch(str + 1, off - 1, ':') + 1;
                if(hasfield)
                    tokbuf_enqueue(&(struct token){.s = COLON, .v = 0});

                tokbuf_enqueue(&(struct token){.s = (!hasfield && str[0] == ':') ? ATOM : IDEN,
                                               .v = (intptr_t)strdup(substring(str+hasfield, sub_off-hasfield))});
            } while(hasfield = 1, str += sub_off, off -= sub_off, off > 0);

            return str;
        }
    }

    tokbuf_enqueue(&tok);
    return str+off;

fail:
    tokbuf_enqueue(&(struct token){.s = END_INPUT});
    return NULL;
}