/*

 * This file is part of mpv.

 *

 * mpv is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * mpv is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.

 */

#include "language.h"

#include <limits.h>

#include <stdint.h>

#include "common/common.h"

#include "misc/ctype.h"

#define L(s) { #s, sizeof(#s) - 1 }

static const struct lang {

    struct { const char s[3] MP_NONSTRING; uint8_t l; } match;

    struct { const char s[3] MP_NONSTRING; uint8_t l; } canonical;

} langmap[] = {

    {L(aa), L(aar)},

    {L(ab), L(abk)},

    {L(ae), L(ave)},

    {L(af), L(afr)},

    {L(ak), L(aka)},

    {L(am), L(amh)},

    {L(an), L(arg)},

    {L(ar), L(ara)},

    {L(as), L(asm)},

    {L(av), L(ava)},

    {L(ay), L(aym)},

    {L(az), L(aze)},

    {L(ba), L(bak)},

    {L(be), L(bel)},

    {L(bg), L(bul)},

    {L(bh), L(bih)},

    {L(bi), L(bis)},

    {L(bm), L(bam)},

    {L(bn), L(ben)},

    {L(bo), L(tib)},

    {L(bod), L(tib)},

    {L(br), L(bre)},

    {L(bs), L(bos)},

    {L(ca), L(cat)},

    {L(ce), L(che)},

    {L(ces), L(cze)},

    {L(ch), L(cha)},

    {L(co), L(cos)},

    {L(cr), L(cre)},

    {L(cs), L(cze)},

    {L(cu), L(chu)},

    {L(cv), L(chv)},

    {L(cy), L(wel)},

    {L(cym), L(wel)},

    {L(da), L(dan)},

    {L(de), L(ger)},

    {L(deu), L(ger)},

    {L(dv), L(div)},

    {L(dz), L(dzo)},

    {L(ee), L(ewe)},

    {L(el), L(gre)},

    {L(ell), L(gre)},

    {L(en), L(eng)},

    {L(eo), L(epo)},

    {L(es), L(spa)},

    {L(et), L(est)},

    {L(eu), L(baq)},

    {L(eus), L(baq)},

    {L(fa), L(per)},

    {L(fas), L(per)},

    {L(ff), L(ful)},

    {L(fi), L(fin)},

    {L(fj), L(fij)},

    {L(fo), L(fao)},

    {L(fr), L(fre)},

    {L(fra), L(fre)},

    {L(fy), L(fry)},

    {L(ga), L(gle)},

    {L(gd), L(gla)},

    {L(gl), L(glg)},

    {L(gn), L(grn)},

    {L(gu), L(guj)},

    {L(gv), L(glv)},

    {L(ha), L(hau)},

    {L(he), L(heb)},

    {L(hi), L(hin)},

    {L(ho), L(hmo)},

    {L(hr), L(hrv)},

    {L(ht), L(hat)},

    {L(hu), L(hun)},

    {L(hy), L(arm)},

    {L(hye), L(arm)},

    {L(hz), L(her)},

    {L(ia), L(ina)},

    {L(id), L(ind)},

    {L(ie), L(ile)},

    {L(ig), L(ibo)},

    {L(ii), L(iii)},

    {L(ik), L(ipk)},

    {L(io), L(ido)},

    {L(is), L(ice)},

    {L(isl), L(ice)},

    {L(it), L(ita)},

    {L(iu), L(iku)},

    {L(ja), L(jpn)},

    {L(jv), L(jav)},

    {L(ka), L(geo)},

    {L(kat), L(geo)},

    {L(kg), L(kon)},

    {L(ki), L(kik)},

    {L(kj), L(kua)},

    {L(kk), L(kaz)},

    {L(kl), L(kal)},

    {L(km), L(khm)},

    {L(kn), L(kan)},

    {L(ko), L(kor)},

    {L(kr), L(kau)},

    {L(ks), L(kas)},

    {L(ku), L(kur)},

    {L(kv), L(kom)},

    {L(kw), L(cor)},

    {L(ky), L(kir)},

    {L(la), L(lat)},

    {L(lb), L(ltz)},

    {L(lg), L(lug)},

    {L(li), L(lim)},

    {L(ln), L(lin)},

    {L(lo), L(lao)},

    {L(lt), L(lit)},

    {L(lu), L(lub)},

    {L(lv), L(lav)},

    {L(mg), L(mlg)},

    {L(mh), L(mah)},

    {L(mi), L(mao)},

    {L(mk), L(mac)},

    {L(mkd), L(mac)},

    {L(ml), L(mal)},

    {L(mn), L(mon)},

    {L(mr), L(mar)},

    {L(mri), L(mao)},

    {L(ms), L(may)},

    {L(msa), L(may)},

    {L(mt), L(mlt)},

    {L(my), L(bur)},

    {L(mya), L(bur)},

    {L(na), L(nau)},

    {L(nb), L(nob)},

    {L(nd), L(nde)},

    {L(ne), L(nep)},

    {L(ng), L(ndo)},

    {L(nl), L(dut)},

    {L(nld), L(dut)},

    {L(nn), L(nno)},

    {L(no), L(nor)},

    {L(nr), L(nbl)},

    {L(nv), L(nav)},

    {L(ny), L(nya)},

    {L(oc), L(oci)},

    {L(oj), L(oji)},

    {L(om), L(orm)},

    {L(or), L(ori)},

    {L(os), L(oss)},

    {L(pa), L(pan)},

    {L(pi), L(pli)},

    {L(pl), L(pol)},

    {L(ps), L(pus)},

    {L(pt), L(por)},

    {L(qu), L(que)},

    {L(rm), L(roh)},

    {L(rn), L(run)},

    {L(ro), L(rum)},

    {L(ron), L(rum)},

    {L(ru), L(rus)},

    {L(rw), L(kin)},

    {L(sa), L(san)},

    {L(sc), L(srd)},

    {L(sd), L(snd)},

    {L(se), L(sme)},

    {L(sg), L(sag)},

    {L(si), L(sin)},

    {L(sk), L(slo)},

    {L(sl), L(slv)},

    {L(slk), L(slo)},

    {L(sm), L(smo)},

    {L(sn), L(sna)},

    {L(so), L(som)},

    {L(sq), L(alb)},

    {L(sqi), L(alb)},

    {L(sr), L(srp)},

    {L(ss), L(ssw)},

    {L(st), L(sot)},

    {L(su), L(sun)},

    {L(sv), L(swe)},

    {L(sw), L(swa)},

    {L(ta), L(tam)},

    {L(te), L(tel)},

    {L(tg), L(tgk)},

    {L(th), L(tha)},

    {L(ti), L(tir)},

    {L(tk), L(tuk)},

    {L(tl), L(tgl)},

    {L(tn), L(tsn)},

    {L(to), L(ton)},

    {L(tr), L(tur)},

    {L(ts), L(tso)},

    {L(tt), L(tat)},

    {L(tw), L(twi)},

    {L(ty), L(tah)},

    {L(ug), L(uig)},

    {L(uk), L(ukr)},

    {L(ur), L(urd)},

    {L(uz), L(uzb)},

    {L(ve), L(ven)},

    {L(vi), L(vie)},

    {L(vo), L(vol)},

    {L(wa), L(wln)},

    {L(wo), L(wol)},

    {L(xh), L(xho)},

    {L(yi), L(yid)},

    {L(yo), L(yor)},

    {L(za), L(zha)},

    {L(zh), L(chi)},

    {L(zho), L(chi)},

    {L(zu), L(zul)},

};

static int lang_compare(const void *key, const void *lang)

{

    const struct lang *l = lang;

    return bstrcasecmp(*(const bstr*)key, (bstr){(unsigned char *)l->match.s, l->match.l});

}

static bstr canonicalize(bstr lang)

{

    const struct lang *l = bsearch(&lang, langmap, MP_ARRAY_SIZE(langmap),

                                   sizeof(langmap[0]), &lang_compare);

    return l ? (bstr){(unsigned char *)l->canonical.s, l->canonical.l} : lang;

}

int mp_match_lang(char **langs, const char *lang)

{

    if (!lang)

        return 0;

    void *ta_ctx = talloc_new(NULL);

    int lang_parts_n = 0;

    bstr *lang_parts = NULL;

    bstr rest = bstr0(lang);

    while (rest.len) {

        bstr s = bstr_split(rest, "-", &rest);

        MP_TARRAY_APPEND(ta_ctx, lang_parts, lang_parts_n, s);

    }

    int best_score = 0;

    if (!lang_parts_n)

        goto done;

    for (int idx = 0; langs && langs[idx]; idx++) {

        rest = bstr0(langs[idx]);

        int part = 0;

        int score = 0;

        while (rest.len) {

            bstr s = bstr_split(rest, "-", &rest);

            if (!part) {

                if (bstrcasecmp(canonicalize(lang_parts[0]), canonicalize(s)))

                    break;

                score = INT_MAX - idx;

                part++;

                continue;

            }

            if (part >= lang_parts_n)

                break;

            if (bstrcasecmp(lang_parts[part], s))

                score -= 1000;

            part++;

        }

        score -= (lang_parts_n - part) * 1000;

        best_score = MPMAX(best_score, score);

    }

done:

    talloc_free(ta_ctx);

    return best_score;

}

bstr mp_guess_lang_from_filename(bstr name, int *lang_start, enum track_flags *flags)

{

    name = bstr_strip(bstr_strip_ext(name));

    if (lang_start)

        *lang_start = -1;

    if (flags)

        *flags = 0;

    if (name.len < 2)

        return (bstr){0};

    int lang_length = 0;

    int i = name.len - 1;

    int suffixes_length = 0;

    char delimiter = '.';

    if (name.start[i] == ')') {

        delimiter = '(';

        i--;

    }

    if (name.start[i] == ']') {

        delimiter = '[';

        i--;

    }

    enum track_flags *f = flags ? flags : &(enum track_flags){0};

    while (true) {

        while (i >= 0 && mp_isalpha(name.start[i])) {

            lang_length++;

            i--;

        }

        if (i >= 0 && lang_length >= 2 && name.start[i] == delimiter) {

            bool matched = false;

            static const char *const suffixes[] = { "sdh", "hi", "cc" };

            bstr tag = { name.start + i + 1, lang_length };

            for (int n = 0; n < MP_ARRAY_SIZE(suffixes); n++) {

                if (!bstrcasecmp0(tag, suffixes[n])) {

                    *f |= TRACK_HEARING_IMPAIRED;

                    matched = true;

                    break;

                }

            }

            if (!bstrcasecmp0(tag, "forced")) {

                *f |= TRACK_FORCED;

                matched = true;

            }

            if (!bstrcasecmp0(tag, "default")) {

                *f |= TRACK_DEFAULT;

                matched = true;

            }

            if (matched) {

                lang_length = 0;

                i -= (delimiter != '.') ? 2 : 1;

                continue;

            }

        }

        // According to

        // https://en.wikipedia.org/wiki/IETF_language_tag#Syntax_of_language_tags

        // subtags after the first are composed of 1 to 8 letters.

        if (lang_length < suffixes_length + 1 || lang_length > suffixes_length + 8)

            return (bstr){0};

        if (i >= 0 && name.start[i] == '-') {

            lang_length++;

            i--;

            suffixes_length = lang_length;

        } else {

            break;

        }

    }

    // The primary subtag can have 2 or 3 letters.

    if (lang_length < suffixes_length + 2 || lang_length > suffixes_length + 3 ||

        i <= 0 || name.start[i] != delimiter)

        return (bstr){0};

    if (lang_start)

        *lang_start = i;

    return (bstr){name.start + i + 1, lang_length};

}