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

// TODO: - lr parser is bad for debugging
//       - deal with errors

#define INPUT_CAP 4096
#define ARENA_CAP 8192 //4096

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

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

    return addr;
}
static void *xcalloc(size_t nmemb, size_t size) { return xalloc(nmemb * size); }
static void xfree(void *ptr) { (void)ptr; return; }

// macros to create the g_ variant of the function
// where everything is cast to and from intptr_t
// so it plays nicely with the lr parser
// #define EMPTY()
// #define DEFER(m) m EMPTY()
// #define EVAL3(...)  EVAL2(EVAL2(EVAL2(EVAL2(__VA_ARGS__))))
// #define EVAL2(...)  EVAL1(EVAL1(EVAL1(EVAL1(__VA_ARGS__))))
// #define EVAL1(...)  __VA_ARGS__

// #define A1(type, name) type name
// #define A2(type, name) intptr_t name
// #define A3(type, name) (type)name

// #define _map2() map2
// #define map2(F, type, name, ...) F(type, name) __VA_OPT__(, DEFER(_map2)()(F, __VA_ARGS__))
// #define map(a, ...) DEFER(_map2)()(a, EVAL1 __VA_ARGS__)

// #define g(ret, name, args) EVAL3( \
    ret name(map(A1, args));  \
    intptr_t g_##name(map(A2, args))  \
    { return (intptr_t)name(map(A3, args)); } \
    ret name(map(A1, args)))

#include "util/list.h"

struct ast_strlist { char *str; struct list_head list; };

struct ast_expr {
    enum { AST_NUMBER, AST_VARIABLE, AST_FIELDLIST, AST_DECLARATION, AST_DEFINITION, AST_OPERATION, AST_PARENLIST } type;
    union {
        int number;
        struct ast_vrbl { int is_atom; char *iden; } variable;
        struct ast_fiel { struct ast_vrbl variable; struct list_head *fields_strlist; } fieldlist;
        struct ast_decl { struct ast_vrbl variable; int typed; } declaration;
        struct ast_defn { struct ast_decl declartion; struct list_head *block_exprlist; } definition;
        struct ast_oprn { enum { AST_OP_AND, AST_OP_OR } optype; struct list_head *left_exprlist; struct list_head *right_exprlist; } operation;
        struct list_head *paren_exprlist;
    };
    struct list_head list;
};

#define NEW(t, ...)  ((struct ast_##t){__VA_ARGS__})
#define g_NEW(t, ...) ((stack_item){.t = (struct ast_##t){__VA_ARGS__}})

#define LST(v) ({ typeof(v) *r = xalloc(sizeof(v)); *r = v; LIST_EMPTY(&r->list); &r->list; })
#define g_LST(v) ((stack_item){.list = LST(v)})

void ast_vrbl_print(struct ast_vrbl *vrbl);
void ast_fiel_print(struct ast_fiel *fiel);
void ast_decl_print(struct ast_decl *decl);
void ast_defn_print(struct ast_defn *defn);
void ast_oprn_print(struct ast_oprn *oprn);
void ast_expr_print(struct ast_expr *expr);
void ast_exprlist_print(struct list_head *list);

void ast_exprlist_free(struct list_head *list);

// 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;
    stack_item v;
};
#define TOKEN_INIT(sym, val) (struct token){ .s = sym, .v = val }
static void print_token(struct token *t);

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

static char *input;
static size_t line = 1;
static size_t active_region;
static char *next_token(char *str);

static inline char *substring(char *str, size_t sub_end);
static inline char *linestart(char *strstart, char *pos);
static inline size_t tillch(char *str, size_t len, char ch);
#define strdup(...) _strdup(__VA_ARGS__)
static inline char *_strdup(char *str);


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

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)
{
    char *filename = "stdin";

    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_SET_ALLOCATOR(&types_dict, xcalloc, xfree);
    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;

    stack_item value;
    struct lr_errinfo *errinfo;
    if((errinfo = lr_parser(&value))) {
        char *l = linestart(input_buf, input);

        fprintf(stderr, "%s:%zu:%zu: ERROR: %s\n", filename, line, input - l - active_region+1, lr_err_str(errinfo));

        size_t indent = fprintf(stderr, "   %zu ", line);
        fprintf(stderr, "| %s\n", substring(l, tillch(l, strlen(l), '\n')));

        fprintf(stderr, "%*s| %*s", indent, "", input - l - active_region, "");
        if(active_region == 0) active_region = 1;
        fprintf(stderr, "^"); for(size_t i = 0; i < active_region-1; i++) fprintf(stderr, "~");

        fprintf(stderr, "\n\n");
        goto cleanup;
    }

    ast_exprlist_print(value.list);
    // ast_exprlist_free(value.list);

cleanup:
    dict_free(&types_dict);
    return 0;
}

static void print_token(struct token *tok)
{
    // TODO: unfinished function
    printf("%s\n", symbol_to_str[token_sym(tok)]);
    switch(token_sym(tok)) {
    case IDEN:
    case ATOM:
        printf("  %s\n", (char *)token_val(tok));
        break;
    default: break;
    }
}

// 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 char *linestart(char *strstart, char *pos)
{
    while(pos-- > strstart) if(*pos == '\n') return pos+1;
    return strstart;
}

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));
        } else {
            tokbuf_enqueue(&TOKEN_INIT(s, { .num = s }));
        }
    }

    str += off;

    switch(str[0]) {
    case '-': return typelist_tokenize(str+1);
    case '(':
        size_t depth = 0;
        while((str = next_token(str)))
            if(str[0] == '(') depth++;
            else if(*(str-1) == ')') {
                if(depth > 0) depth--;
                else 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 == '\n') line++;
    if(isspace(c0)) return next_token(str+1);

    if(c0 == '\0') tok.s = END_INPUT;
    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 '/':
                char *s2 = str;
                tok.s = TYPELIST_START; tokbuf_enqueue(&tok);
                if(!(s2 = typelist_tokenize(s2+off))) goto fail;
                tok.s = TYPELIST_END; tokbuf_enqueue(&tok);
                active_region = s2 - str; return s2;
            default: fprintf(stderr, "ERROR: Unknown sep '%c'\n", c0); break;
            }
        } else if(c0 >= '0' && c0 <= '9') { // num
            tok.s = NUM;
            tok.v = (stack_item){ .num = atoi(substring(str, off)) }; // not really
        } else { // iden or atom (possibly with fields)
            active_region = off;
            int hasfield = 0;
            size_t sub_off;

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

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

            return str;
        }
    }

    tokbuf_enqueue(&tok);
    active_region = off;
    return str+off;

fail:
    exit(14);
    // tok.s = END_INPUT; tokbuf_enqueue(&tok);
    // return NULL;
}

// ast printing

void ast_vrbl_print(struct ast_vrbl *vrbl)
{
    printf("%s%s", vrbl->is_atom ? ":" : "", vrbl->iden);
}

void ast_fiel_print(struct ast_fiel *fiel)
{
    ast_vrbl_print(&fiel->variable);
    list_for_each_entry(struct ast_strlist, entry, list, fiel->fields_strlist) {
        printf(":%s", entry->str);
    }
}

void ast_decl_print(struct ast_decl *decl)
{
    // TODO: implement
}

void ast_defn_print(struct ast_defn *defn)
{
    // TODO: implement
}

void ast_oprn_print(struct ast_oprn *oprn)
{
    ast_exprlist_print(oprn->left_exprlist);
    if(oprn->optype == AST_OP_AND) printf(",\n"); else printf(";\n");
    ast_exprlist_print(oprn->right_exprlist);
}

void ast_expr_print(struct ast_expr *expr) { ast_exprlist_print(&expr->list); }
void ast_exprlist_print(struct list_head *list)
{
    list_for_each_entry(struct ast_expr, entry, list, list)
    {
        switch(entry->type) {
        case AST_NUMBER: printf("%d", entry->number); break;
        case AST_VARIABLE: ast_vrbl_print(&entry->variable); break;
        case AST_FIELDLIST: ast_fiel_print(&entry->fieldlist); break;
        case AST_DECLARATION: ast_decl_print(&entry->declaration); break;
        case AST_OPERATION: ast_oprn_print(&entry->operation); break;
        case AST_PARENLIST:
            printf("(");
            ast_exprlist_print(entry->paren_exprlist);
            printf(")");
            break;
        default: fprintf(stderr, "UNKNOWN TYPE: %d\n", entry->type);
        }
        printf(" ");
    }
    printf("\n");
}

void ast_exprlist_free(struct list_head *list)
{
    list_for_each_safe(l, list) {
        struct ast_expr *entry = list_entry(l, typeof(*entry), list);

        switch(entry->type) {
        case AST_NUMBER: break;
        case AST_VARIABLE: break;
        case AST_FIELDLIST:
            list_for_each_safe(l, entry->fieldlist.fields_strlist)
                free(list_entry(l, struct ast_strlist, list));
            break;
        case AST_DECLARATION: break;
        case AST_DEFINITION:  break;
        case AST_OPERATION:
            ast_exprlist_free(entry->operation.left_exprlist);
            ast_exprlist_free(entry->operation.right_exprlist);
            break;
        case AST_PARENLIST: ast_exprlist_free(entry->paren_exprlist); break;
        default: fprintf(stderr, "UNKNOWN TYPE: %d\n", entry->type);
        }

        free(entry);
    }
}