#include <assert.h>

#include <debug.h>

#include <memory/srealloc.h>

#include <parse/istream/struct.h>
#include <parse/istream/read.h>

#include "struct.h"
#include "next.h"

static const enum state {
    s_error,
    
    s_EOF,
    
    s_null,
    
    s_true,
    
    s_false,
    
    s_integer,
    
    // symbols:
    s_gravemark,
    s_oparen,
    s_cparen,
    
    s_identifier,
    
    s_start,
    
    s_skipping_comment,
    
    s_reading_oparen,
    s_reading_cparen,
    
    s_reading_integer,
    
    s_reading_identifier,
    
    s_reading_gravemark,
    
    s_reading_n,
    s_reading_nu,
    s_reading_nul,
    s_reading_null,
    
    s_reading_t,
    s_reading_tr,
    s_reading_tru,
    s_reading_true,
    
    s_reading_f,
    s_reading_fa,
    s_reading_fal,
    s_reading_fals,
    s_reading_false,
    
    number_of_states,
} lookup[number_of_states][256] = {
    
    #define ANY 0 ... 255
    
    // EOF:
    [s_start][0] = s_EOF,
    
    // skip whitespace
    [s_start][' '] = s_start,
    [s_start]['\t'] = s_start,
    [s_start]['\n'] = s_start,
    
    // skip comments:
    [s_start]['#'] = s_skipping_comment,
        [s_skipping_comment][ANY] = s_skipping_comment,
        [s_skipping_comment]['\n'] = s_start,
    
    // brackets:
    [s_start]['('] = s_reading_oparen,
        [s_reading_oparen][ANY] = s_oparen,
    [s_start][')'] = s_reading_cparen,
        [s_reading_cparen][ANY] = s_cparen,
    
    // symbols:
    [s_start]['`'] = s_reading_gravemark,
        [s_reading_gravemark][ANY] = s_gravemark,
    
    // integer literals:
    [s_start]['0' ... '9'] = s_reading_integer,
        [s_reading_integer][    ANY    ] = s_integer,
        [s_reading_integer]['0' ... '9'] = s_reading_integer,
    
    // identifiers
    [s_start]['?'] = s_reading_identifier,
    [s_start]['!'] = s_reading_identifier,
    [s_start]['>'] = s_reading_identifier,
    [s_start]['<'] = s_reading_identifier,
    [s_start]['='] = s_reading_identifier,
    [s_start]['+'] = s_reading_identifier,
    [s_start]['*'] = s_reading_identifier,
    [s_start]['_'] = s_reading_identifier,
    [s_start]['-'] = s_reading_identifier,
    [s_start]['/'] = s_reading_identifier,
    [s_start]['a' ... 'z'] = s_reading_identifier,
    [s_start]['A' ... 'Z'] = s_reading_identifier,
        [s_reading_identifier][ANY] = s_identifier,
        [s_reading_identifier][':'] = s_reading_identifier,
        [s_reading_identifier]['='] = s_reading_identifier,
        [s_reading_identifier]['!'] = s_reading_identifier,
        [s_reading_identifier]['+'] = s_reading_identifier,
        [s_reading_identifier]['*'] = s_reading_identifier,
        [s_reading_identifier]['_'] = s_reading_identifier,
        [s_reading_identifier]['/'] = s_reading_identifier,
        [s_reading_identifier]['-'] = s_reading_identifier,
        [s_reading_identifier]['a' ... 'z'] = s_reading_identifier,
        [s_reading_identifier]['A' ... 'Z'] = s_reading_identifier,
        [s_reading_identifier]['0' ... '9'] = s_reading_identifier,
    
    // "null" keyword:
    [s_start]['n'] = s_reading_n,
        [s_reading_n][ANY] = s_identifier,
        [s_reading_n]['_'] = s_reading_identifier,
        [s_reading_n]['-'] = s_reading_identifier,
        [s_reading_n]['a' ... 'z'] = s_reading_identifier,
        [s_reading_n]['A' ... 'Z'] = s_reading_identifier,
        [s_reading_n]['u'] = s_reading_nu,
            [s_reading_nu][ANY] = s_identifier,
            [s_reading_nu]['_'] = s_reading_identifier,
            [s_reading_nu]['-'] = s_reading_identifier,
            [s_reading_nu]['a' ... 'z'] = s_reading_identifier,
            [s_reading_nu]['A' ... 'Z'] = s_reading_identifier,
            [s_reading_nu]['l'] = s_reading_nul,
                [s_reading_nul][ANY] = s_identifier,
                [s_reading_nul]['_'] = s_reading_identifier,
                [s_reading_nul]['-'] = s_reading_identifier,
                [s_reading_nul]['a' ... 'z'] = s_reading_identifier,
                [s_reading_nul]['A' ... 'Z'] = s_reading_identifier,
                [s_reading_nul]['l'] = s_reading_null,
                    [s_reading_null][ANY] = s_null,
                    [s_reading_null]['_'] = s_reading_identifier,
                    [s_reading_null]['-'] = s_reading_identifier,
                    [s_reading_null]['a' ... 'z'] = s_reading_identifier,
                    [s_reading_null]['A' ... 'Z'] = s_reading_identifier,
    
    // "true" keyword:
    [s_start]['t'] = s_reading_t,
        [s_reading_t][ANY] = s_identifier,
        [s_reading_t]['_'] = s_reading_identifier,
        [s_reading_t]['-'] = s_reading_identifier,
        [s_reading_t]['a' ... 'z'] = s_reading_identifier,
        [s_reading_t]['A' ... 'Z'] = s_reading_identifier,
        [s_reading_t]['r'] = s_reading_tr,
            [s_reading_tr][ANY] = s_identifier,
            [s_reading_tr]['_'] = s_reading_identifier,
            [s_reading_tr]['-'] = s_reading_identifier,
            [s_reading_tr]['a' ... 'z'] = s_reading_identifier,
            [s_reading_tr]['A' ... 'Z'] = s_reading_identifier,
            [s_reading_tr]['u'] = s_reading_tru,
                [s_reading_tru][ANY] = s_identifier,
                [s_reading_tru]['_'] = s_reading_identifier,
                [s_reading_tru]['-'] = s_reading_identifier,
                [s_reading_tru]['a' ... 'z'] = s_reading_identifier,
                [s_reading_tru]['A' ... 'Z'] = s_reading_identifier,
                [s_reading_tru]['e'] = s_reading_true,
                    [s_reading_true][ANY] = s_true,
                    [s_reading_true]['_'] = s_reading_identifier,
                    [s_reading_true]['-'] = s_reading_identifier,
                    [s_reading_true]['a' ... 'z'] = s_reading_identifier,
                    [s_reading_true]['A' ... 'Z'] = s_reading_identifier,
    
    // "false" keyword:
    [s_start]['f'] = s_reading_f,
        [s_reading_f][ANY] = s_identifier,
        [s_reading_f]['_'] = s_reading_identifier,
        [s_reading_f]['-'] = s_reading_identifier,
        [s_reading_f]['a' ... 'z'] = s_reading_identifier,
        [s_reading_f]['A' ... 'Z'] = s_reading_identifier,
        [s_reading_f]['a'] = s_reading_fa,
            [s_reading_fa][ANY] = s_identifier,
            [s_reading_fa]['_'] = s_reading_identifier,
            [s_reading_fa]['-'] = s_reading_identifier,
            [s_reading_fa]['a' ... 'z'] = s_reading_identifier,
            [s_reading_fa]['A' ... 'Z'] = s_reading_identifier,
            [s_reading_fa]['l'] = s_reading_fal,
                [s_reading_fal][ANY] = s_identifier,
                [s_reading_fal]['_'] = s_reading_identifier,
                [s_reading_fal]['-'] = s_reading_identifier,
                [s_reading_fal]['a' ... 'z'] = s_reading_identifier,
                [s_reading_fal]['A' ... 'Z'] = s_reading_identifier,
                [s_reading_fal]['s'] = s_reading_fals,
                    [s_reading_fals][ANY] = s_identifier,
                    [s_reading_fals]['_'] = s_reading_identifier,
                    [s_reading_fals]['-'] = s_reading_identifier,
                    [s_reading_fals]['a' ... 'z'] = s_reading_identifier,
                    [s_reading_fals]['A' ... 'Z'] = s_reading_identifier,
                    [s_reading_fals]['e'] = s_reading_false,
                        [s_reading_false][ANY] = s_false,
                        [s_reading_false]['_'] = s_reading_identifier,
                        [s_reading_false]['-'] = s_reading_identifier,
                        [s_reading_false]['a' ... 'z'] = s_reading_identifier,
                        [s_reading_false]['A' ... 'Z'] = s_reading_identifier,
};

void tokenizer_next_token(
    struct tokenizer* this)
{
    ENTER;
    
    this->rawtoken.n = 0;
    
    void append(uint8_t c)
    {
        ENTER;
        
        if (this->rawtoken.n == this->rawtoken.cap)
        {
            this->rawtoken.cap = this->rawtoken.cap << 1 ?: 1;
            
            this->rawtoken.data = srealloc(
                this->rawtoken.data,
                sizeof(*this->rawtoken.data) * this->rawtoken.cap);
        }
        
        this->rawtoken.data[this->rawtoken.n++] = c;
        
        EXIT;
    }
    
    enum state state = s_start;
    
    while (state >= s_start)
    {
        dpvc(this->stream->c);
        
        state = lookup[state][this->stream->c];
        
        if (state > s_start)
        {
            append(this->stream->c);
            
            istream_read(this->stream);
        }
        
        if (state == s_start)
        {
            this->rawtoken.n = 0;
            
            istream_read(this->stream);
        }
    }
    
    append(0), this->rawtoken.n--;
    
    switch (state)
    {
        case s_error:
        {
            TODO;
            
            break;
        }
        
        case s_EOF:
        {
            this->token = t_EOF;
            
            break;
        }
        
        case s_gravemark:
        {
            this->token = t_gravemark;
            
            break;
        }
        
        case s_oparen:
        {
            this->token = t_oparen;
            
            break;
        }
        
        case s_cparen:
        {
            this->token = t_cparen;
            
            break;
        }
        
        case s_null:
        {
            this->token = t_null;
            
            break;
        }
        
        case s_true:
        {
            this->token = t_true;
            
            break;
        }
        
        case s_false:
        {
            this->token = t_false;
            
            break;
        }
        
        case s_identifier:
        {
            this->token = t_identifier;
            
            break;
        }
        
        case s_integer:
        {
            this->token = t_integer;
            
            break;
        }
        
        default:
            TODO;
            break;
    }
    
    EXIT;
}