/* retoor <retoor@molodetz.nl> */
#ifndef LOREX_NFA_H
#define LOREX_NFA_H

#include "ast.h"
#include "lorex.h"
#include <stdbool.h>
#include <stddef.h>

#define EPSILON '\0'
#define NFA_MAX_TRANSITIONS 256

typedef struct nfa_state nfa_state_t;

typedef enum {
    TRANS_CHAR,
    TRANS_EPSILON,
    TRANS_DOT,
    TRANS_BRACKET,
    TRANS_CLASS_DIGIT,
    TRANS_CLASS_WORD,
    TRANS_CLASS_SPACE,
    TRANS_CLASS_NDIGIT,
    TRANS_CLASS_NWORD,
    TRANS_CLASS_NSPACE,
    TRANS_GROUP_START,
    TRANS_GROUP_END,
    TRANS_ANCHOR_START,
    TRANS_ANCHOR_END
} transition_type_t;

typedef struct {
    nfa_state_t *target;
    bracket_class_t *bracket;
    transition_type_t type;
    int group_id;
    char value;
} transition_t;

struct nfa_state {
    transition_t *transitions;
    size_t trans_count;
    size_t trans_capacity;
    int id;
    bool accepting;
};

typedef struct {
    nfa_state_t *start;
    nfa_state_t *accept;
} nfa_fragment_t;

typedef struct {
    nfa_state_t **states;
    nfa_state_t *start;
    char *literal_prefix;
    char *literal_suffix;
    size_t state_count;
    size_t capacity;
    size_t prefix_len;
    size_t suffix_len;
    int group_count;
    char single_first_char;
    bool anchored_start;
    bool anchored_end;
    bool first_chars_valid;
    bool is_pure_literal;
    bool has_alt_dispatch;
    unsigned char first_chars[32];
    unsigned char alt_dispatch[256];
} nfa_t;

nfa_t *nfa_create(void);
void nfa_free(nfa_t *nfa);
nfa_state_t *nfa_add_state(nfa_t *nfa);
void nfa_add_transition(nfa_state_t *from, nfa_state_t *to, transition_type_t type, char value);
void nfa_add_bracket_transition(nfa_state_t *from, nfa_state_t *to, bracket_class_t *bracket);
void nfa_add_group_transition(nfa_state_t *from, nfa_state_t *to, transition_type_t type, int group_id);
nfa_t *nfa_from_ast(ast_node_t *ast, lorex_error_t *error);

#endif