/* MIT License
 *
 * Copyright (c) 2023 Tyge Løvset
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#define i_header // external linkage by default. override with i_static.
#define _i_inc_utf8
#include "utf8.h"

#ifndef CSUBSTR_H_INCLUDED
#define CSUBSTR_H_INCLUDED

#define             csubstr_init() c_ss_1("")
#define             csubstr_drop(p) c_default_drop(p)
#define             csubstr_clone(ss) c_default_clone(ss)
#define             csubstr_from_n(str, n) c_ss_2(str, n)

STC_API csubstr_iter csubstr_advance(csubstr_iter it, intptr_t pos);
STC_API intptr_t    csubstr_find_ss(csubstr ss, csubstr search);
STC_API uint64_t    csubstr_hash(const csubstr *self);
STC_API csubstr     csubstr_slice_ex(csubstr ss, intptr_t p1, intptr_t p2);
STC_API csubstr     csubstr_substr_ex(csubstr ss, intptr_t pos, intptr_t n);
STC_API csubstr     csubstr_token(csubstr ss, const char* sep, intptr_t* start);

STC_INLINE csubstr  csubstr_from(const char* str)
    { return c_LITERAL(csubstr){str, c_strlen(str)}; }
STC_INLINE void     csubstr_clear(csubstr* self) { *self = csubstr_init(); }
STC_INLINE intptr_t csubstr_size(csubstr ss) { return ss.size; }
STC_INLINE bool     csubstr_empty(csubstr ss) { return ss.size == 0; }

STC_INLINE bool csubstr_equals(csubstr ss, const char* str)
    { intptr_t n = c_strlen(str); return ss.size == n && !c_memcmp(ss.str, str, n); }

STC_INLINE intptr_t csubstr_find(csubstr ss, const char* str)
    { return csubstr_find_ss(ss, c_ss_2(str, c_strlen(str))); }

STC_INLINE bool csubstr_contains(csubstr ss, const char* str)
    { return csubstr_find(ss, str) != c_NPOS; }

STC_INLINE bool csubstr_starts_with(csubstr ss, const char* str) {
    intptr_t n = c_strlen(str);
    return n > ss.size ? false : !c_memcmp(ss.str, str, n);
}

STC_INLINE bool csubstr_ends_with(csubstr ss, const char* str) {
    intptr_t n = c_strlen(str);
    return n > ss.size ? false : !c_memcmp(ss.str + ss.size - n, str, n);
}

STC_INLINE csubstr csubstr_substr(csubstr ss, intptr_t pos, intptr_t n) {
    if (pos + n > ss.size) n = ss.size - pos;
    ss.str += pos, ss.size = n;
    return ss;
}

STC_INLINE csubstr csubstr_slice(csubstr ss, intptr_t p1, intptr_t p2) {
    if (p2 > ss.size) p2 = ss.size;
    ss.str += p1, ss.size = p2 > p1 ? p2 - p1 : 0;
    return ss;
}

/* utf8 iterator */
STC_INLINE csubstr_iter csubstr_begin(const csubstr* self) { 
    if (!self->size) return c_LITERAL(csubstr_iter){NULL};
    return c_LITERAL(csubstr_iter){.u8 = {{self->str, utf8_chr_size(self->str)},
                                           self->str + self->size}};
}
STC_INLINE csubstr_iter csubstr_end(const csubstr* self) {
    return c_LITERAL(csubstr_iter){.u8 = {{NULL}, self->str + self->size}};
}
STC_INLINE void csubstr_next(csubstr_iter* it) {
    it->ref += it->u8.chr.size;
    it->u8.chr.size = utf8_chr_size(it->ref);
    if (it->ref == it->u8.end) it->ref = NULL;
}

/* utf8 */
STC_INLINE intptr_t csubstr_u8_size(csubstr ss)
    { return utf8_size_n(ss.str, ss.size); }

STC_INLINE csubstr csubstr_u8_substr(csubstr ss, intptr_t bytepos, intptr_t u8len) {
    ss.str += bytepos;
    ss.size = utf8_pos(ss.str, u8len);
    return ss;
}

STC_INLINE bool csubstr_valid_utf8(csubstr ss) // depends on src/utf8code.c
    { return utf8_valid_n(ss.str, ss.size); }

#define c_fortoken_ss(it, inputss, sep) \
    for (struct { csubstr _inp, token, *ref; const char *_sep; intptr_t pos; } \
          it = {._inp=inputss, .token=it._inp, .ref=&it.token, ._sep=sep} \
        ; it.pos <= it._inp.size && (it.token = csubstr_token(it._inp, it._sep, &it.pos)).str ; )

#define c_fortoken(it, input, sep) \
    c_fortoken_ss(it, csubstr_from(input), sep)

/* ---- Container helper functions ---- */

STC_INLINE int csubstr_cmp(const csubstr* x, const csubstr* y) {
    intptr_t n = x->size < y->size ? x->size : y->size;
    int c = c_memcmp(x->str, y->str, n);
    return c ? c : (int)(x->size - y->size);
}

STC_INLINE int csubstr_icmp(const csubstr* x, const csubstr* y)
    { return utf8_icmp_ss(*x, *y); }

STC_INLINE bool csubstr_eq(const csubstr* x, const csubstr* y)
    { return x->size == y->size && !c_memcmp(x->str, y->str, x->size); }

#endif // CSUBSTR_H_INCLUDED

/* csubstr interaction with cstr: */
#ifdef CSTR_H_INCLUDED

STC_INLINE csubstr cstr_substr(const cstr* self, intptr_t pos, intptr_t n)
    { return csubstr_substr(cstr_ss(self), pos, n); }

STC_INLINE csubstr cstr_slice(const cstr* self, intptr_t p1, intptr_t p2)
    { return csubstr_slice(cstr_ss(self), p1, p2); }

STC_INLINE csubstr cstr_substr_ex(const cstr* self, intptr_t pos, intptr_t n)
    { return csubstr_substr_ex(cstr_ss(self), pos, n); }

STC_INLINE csubstr cstr_slice_ex(const cstr* self, intptr_t p1, intptr_t p2)
    { return csubstr_slice_ex(cstr_ss(self), p1, p2); }

STC_INLINE csubstr cstr_u8_substr(const cstr* self , intptr_t bytepos, intptr_t u8len)
    { return csubstr_u8_substr(cstr_ss(self), bytepos, u8len); }
#endif

/* -------------------------- IMPLEMENTATION ------------------------- */
#if defined i_implement || defined i_static
#ifndef CSUBSTR_C_INCLUDED
#define CSUBSTR_C_INCLUDED

STC_DEF csubstr_iter csubstr_advance(csubstr_iter it, intptr_t pos) {
    int inc = -1;
    if (pos > 0) pos = -pos, inc = 1;
    while (pos && it.ref != it.u8.end) pos += (*(it.ref += inc) & 0xC0) != 0x80;
    it.u8.chr.size = utf8_chr_size(it.ref);
    if (it.ref == it.u8.end) it.ref = NULL;
    return it;
}

STC_DEF intptr_t csubstr_find_ss(csubstr ss, csubstr search) {
    char* res = cstrnstrn(ss.str, search.str, ss.size, search.size);
    return res ? (res - ss.str) : c_NPOS;
}

STC_DEF uint64_t csubstr_hash(const csubstr *self)
    { return cfasthash(self->str, self->size); }

STC_DEF csubstr csubstr_substr_ex(csubstr ss, intptr_t pos, intptr_t n) {
    if (pos < 0) { 
        pos += ss.size;
        if (pos < 0) pos = 0;
    }
    if (pos > ss.size) pos = ss.size;
    if (pos + n > ss.size) n = ss.size - pos;
    ss.str += pos, ss.size = n;
    return ss;
}

STC_DEF csubstr csubstr_slice_ex(csubstr ss, intptr_t p1, intptr_t p2) {
    if (p1 < 0) { 
        p1 += ss.size;
        if (p1 < 0) p1 = 0;
    }
    if (p2 < 0) p2 += ss.size;
    if (p2 > ss.size) p2 = ss.size;
    ss.str += p1, ss.size = (p2 > p1 ? p2 - p1 : 0);
    return ss;
}

STC_DEF csubstr csubstr_token(csubstr ss, const char* sep, intptr_t* start) {
    intptr_t sep_size = c_strlen(sep);
    csubstr slice = {ss.str + *start, ss.size - *start};
    const char* res = cstrnstrn(slice.str, sep, slice.size, sep_size);
    csubstr tok = {slice.str, res ? (res - slice.str) : slice.size};
    *start += tok.size + sep_size;
    return tok;
}
#endif // CSUBSTR_C_INCLUDED
#endif // i_implement
#undef i_static
#undef i_header
#undef i_implement
#undef i_import
#undef i_opt