#ifndef REGEX_H
#define REGEX_H

#include <stdint.h>

#include "arena.h"
#include "dynarr.h"
#include "str.h"

typedef enum : u8 {
	RE_CHAR,
	RE_CHAR_NOT,
	RE_CHAR_ANY,
	RE_CHAR_SET,
	RE_CHAR_RANGE,
	RE_CHAR_RANGE_NOT,
	RE_CHAR_SET_PACKED,
	RE_CHAR_SET_PACKED_NOT,
	RE_LINE_START,
	RE_LINE_END,
	RE_MATCH,
	RE_FAIL,
	RE_JUMP,
	RE_SPLIT,
	RE_GROUP_START,
	RE_GROUP_END,
	RE_LABEL /* only used during codegen */
} ReOpType;

typedef union {
	struct {
		ReOpType op;
		union {
			uint32_t c;
			struct {
				u16 a, b;
			};
		};
	};
	u64 align;
} ReOp;

typedef struct {
	uint32_t min, max;
} ReChRange;

typedef struct {
	/* sorted list of non-overlapping character ranges */
	ReChRange *v;
	uint32_t n;
	int invert;
} ReChSet;

/* for RE_CHAR */
typedef enum {
	C_ANY = 0x40000000,
	C_LINE_START,
	C_LINE_END,
} ReChSpecial;

typedef struct {
	DYNARR(ReOp) op;
	DYNARR(ReChSet) cset;
	uint32_t groups;
	u8 first_byte; /* 0 if unknown */
} RegEx;

typedef struct {
	uint32_t start, len;
} ReSpan;

typedef struct {
	ReSpan extent;
	ReSpan *grp;
} ReMatch;

typedef DYNARR(ReMatch) ReMatchList;

typedef struct {
	u32 i;
	ReSpan *grp;
} ReThread;

typedef struct {
	ReThread *v;
	uintmax_t *set;
	size_t n;
} ReThreadList;

typedef enum {
	RE_SEARCH_FIRST_CHUNK = 1,
	RE_SEARCH_LAST_CHUNK  = 2,
	RE_SEARCH_MID_MATCH   = 4,
	RE_SEARCH_WAS_NEWLINE = 8,
} ReSearchFlags;

typedef struct {
	Arena *a;
	RegEx *re;
	ReSpan *grp;
	const char *buf;
	size_t buf_len, buf_idx;
	size_t total_idx;
	size_t match_start, match_end;
	ReThreadList tcur, tnext;
	ReSearchFlags flags;
	uint32_t c, c_prev;
} ReSearch;

typedef enum {
	RE_COMP_NO_GROUPS = 1
} ReCompFlags;

typedef enum {
	RE_COMP_ENONE,
	RE_COMP_ENORPAREN,
	RE_COMP_ENOLPAREN,
	RE_COMP_EEOF,
} ReCompErr;

int re_comp(RegEx *re, Str src, Arena *perm, Arena *scratch);
int re_comp_ex(RegEx *re, Str src, Arena *perm, Arena *scratch, ReCompFlags flags);
const char *re_comp_strerror(ReCompErr err);

void re_search_start(ReSearch *s, RegEx *re, Arena *a);
void re_search_chunk(ReSearch *s, const char *buf, size_t n);
void re_search_first_chunk(ReSearch *s);
void re_search_last_chunk(ReSearch *s);
int re_search_match(ReSearch *s, ReMatch *m);
int re_search_match_at_start(ReSearch *s, ReMatch *m);

ReMatchList re_match_all(RegEx *re, Str s, Arena *a);
int re_match_full(RegEx *re, Str s, Arena *a);
int re_match(RegEx *re, Str s, ReMatch *out, Arena *a);

#endif