/*

 * 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 <stdlib.h>

#include <string.h>

#include <libavutil/common.h>

#include "common/common.h"

#include "options/options.h"

#include "options/m_config.h"

#include "common/msg.h"

#include "common/playlist.h"

#include "misc/charset_conv.h"

#include "misc/thread_tools.h"

#include "options/path.h"

#include "player/core.h"

#include "stream/stream.h"

#include "osdep/io.h"

#include "misc/natural_sort.h"

#include "demux.h"

#define PROBE_SIZE (8 * 1024)

enum dir_mode {

    DIR_AUTO,

    DIR_LAZY,

    DIR_RECURSIVE,

    DIR_IGNORE,

};

enum autocreate_mode {

    AUTO_NONE     = 0,

    AUTO_VIDEO    = 1 << 0,

    AUTO_AUDIO    = 1 << 1,

    AUTO_IMAGE    = 1 << 2,

    AUTO_ARCHIVE  = 1 << 3,

    AUTO_PLAYLIST = 1 << 4,

    AUTO_ANY      = 1 << 5,

};

#define OPT_BASE_STRUCT struct demux_playlist_opts

struct demux_playlist_opts {

    int dir_mode;

};

struct m_sub_options demux_playlist_conf = {

    .opts = (const struct m_option[]) {

        {"directory-mode", OPT_CHOICE(dir_mode,

            {"auto", DIR_AUTO},

            {"lazy", DIR_LAZY},

            {"recursive", DIR_RECURSIVE},

            {"ignore", DIR_IGNORE})},

        {0}

    },

    .size = sizeof(struct demux_playlist_opts),

    .defaults = &(const struct demux_playlist_opts){

        .dir_mode = DIR_AUTO,

    },

    .change_flags = UPDATE_DEMUXER,

};

static bool check_mimetype(struct stream *s, const char *const *list)

{

    if (s->mime_type) {

        for (int n = 0; list && list[n]; n++) {

            if (strcasecmp(s->mime_type, list[n]) == 0)

                return true;

        }

    }

    return false;

}

struct pl_parser {

    struct mpv_global *global;

    struct mp_log *log;

    struct stream *s;

    char buffer[2 * 1024 * 1024];

    int utf16;

    struct playlist *pl;

    bool error;

    bool probing;

    bool force;

    bool line_allocated;

    int autocreate_playlist;

    enum demux_check check_level;

    struct stream *real_stream;

    const char *format;

    char *codepage;

    char **directory_filter;

    struct demux_playlist_opts *opts;

    struct MPOpts *mp_opts;

};

static uint16_t stream_read_word_endian(stream_t *s, bool big_endian)

{

    unsigned int y = stream_read_char(s);

    y = (y << 8) | stream_read_char(s);

    if (!big_endian)

        y = ((y >> 8) & 0xFF) | (y << 8);

    return y;

}

// Read characters until the next '\n' (including), or until the buffer in s is

// exhausted.

static int read_characters(stream_t *s, uint8_t *dst, int dstsize, int utf16)

{

    if (utf16 == 1 || utf16 == 2) {

        uint8_t *cur = dst;

        while (1) {

            if ((cur - dst) + 8 >= dstsize) // PUT_UTF8 writes max. 8 bytes

                return -1; // line too long

            uint32_t c;

            uint8_t tmp;

            GET_UTF16(c, stream_read_word_endian(s, utf16 == 2), return -1;)

            if (s->eof)

                break; // legitimate EOF; ignore the case of partial reads

            PUT_UTF8(c, tmp, *cur++ = tmp;)

            if (c == '\n')

                break;

        }

        return cur - dst;

    } else {

        uint8_t buf[1024];

        int buf_len = stream_read_peek(s, buf, sizeof(buf));

        uint8_t *end = memchr(buf, '\n', buf_len);

        int len = end ? end - buf + 1 : buf_len;

        if (len > dstsize)

            return -1; // line too long

        memcpy(dst, buf, len);

        stream_seek_skip(s, stream_tell(s) + len);

        return len;

    }

}

// On error, or if the line is larger than max-1, return NULL and unset s->eof.

// On EOF, return NULL, and s->eof will be set.

// Otherwise, return the line (including \n or \r\n at the end of the line).

// If the return value is non-NULL, it's always the same as mem.

// utf16: 0: UTF8 or 8 bit legacy, 1: UTF16-LE, 2: UTF16-BE

static char *read_line(stream_t *s, char *mem, int max, int utf16)

{

    if (max < 1)

        return NULL;

    int read = 0;

    while (1) {

        // Reserve 1 byte of ptr for terminating \0.

        int l = read_characters(s, &mem[read], max - read - 1, utf16);

        if (l < 0 || memchr(&mem[read], '\0', l)) {

            MP_WARN(s, "error reading line\n");

            return NULL;

        }

        read += l;

        if (l == 0 || (read > 0 && mem[read - 1] == '\n'))

            break;

    }

    mem[read] = '\0';

    if (!stream_read_peek(s, &(char){0}, 1) && read == 0) // legitimate EOF

        return NULL;

    return mem;

}

static char *pl_get_line0(struct pl_parser *p)

{

    char *res = read_line(p->s, p->buffer, sizeof(p->buffer), p->utf16);

    if (res) {

        int len = strlen(res);

        if (len > 0 && res[len - 1] == '\n')

            res[len - 1] = '\0';

    } else {

        p->error |= !p->s->eof;

    }

    return res;

}

static bstr pl_get_line(struct pl_parser *p)

{

    bstr line = bstr_strip(bstr0(pl_get_line0(p)));

    const char *charset = mp_charset_guess(p, p->log, line, p->codepage, 0);

    if (charset && !mp_charset_is_utf8(charset)) {

        bstr utf8 = mp_iconv_to_utf8(p->log, line, charset, 0);

        if (utf8.start && utf8.start != line.start) {

            line = utf8;

            p->line_allocated = true;

        }

    }

    return line;

}

// Helper in case mp_iconv_to_utf8 allocates memory

static void pl_free_line(struct pl_parser *p, bstr line)

{

    if (p->line_allocated) {

        talloc_free(line.start);

        p->line_allocated = false;

    }

}

static void pl_add(struct pl_parser *p, bstr entry)

{

    void *ctx = talloc_new(NULL);

    char *path = mp_get_user_path(ctx, p->global, bstrto0(ctx, entry));

    bstr proto = mp_split_proto(bstr0(p->s->url), NULL);

    // Don't add base path to self-expanding protocols

    if (!mp_is_url(entry) && bstrcasecmp0(proto, "memory") &&

        bstrcasecmp0(proto, "lavf") && bstrcasecmp0(proto, "hex") &&

        bstrcasecmp0(proto, "data") && bstrcasecmp0(proto, "fd")) {

        const char *base = p->s->effective_url ? p->s->effective_url : p->s->url;

        path = mp_path_join_bstr(ctx, mp_dirname(base), bstr0(path));

    }

    playlist_append_file(p->pl, path);

    talloc_free(ctx);

}

static bool pl_eof(struct pl_parser *p)

{

    return p->error || p->s->eof;

}

static bool maybe_text(bstr d)

{

    for (int n = 0; n < d.len; n++) {

        unsigned char c = d.start[n];

        if (c < 32 && c != '\n' && c != '\r' && c != '\t')

            return false;

    }

    return true;

}

static int parse_m3u(struct pl_parser *p)

{

    bstr line = pl_get_line(p);

    if (p->probing && !bstr_equals0(line, "#EXTM3U")) {

        // Last resort: if the file extension is m3u, it might be headerless.

        if (p->check_level == DEMUX_CHECK_UNSAFE) {

            bstr ext = mp_get_ext(bstr0(p->real_stream->url));

            char probe[PROBE_SIZE];

            int len = stream_read_peek(p->real_stream, probe, sizeof(probe));

            bstr data = {probe, len};

            if (ext.len && data.len >= 2 && maybe_text(data)) {

                const char *exts[] = {"m3u", "m3u8", "strm", NULL};

                for (int n = 0; exts[n]; n++) {

                    if (bstrcasecmp(ext, bstr0(exts[n])) == 0)

                        goto ok;

                }

            }

        }

        pl_free_line(p, line);

        return -1;

    }

ok:

    if (p->probing) {

        pl_free_line(p, line);

        return 0;

    }

    char *title = NULL;

    while (line.len || !pl_eof(p)) {

        bstr line_dup = line;

        if (bstr_eatstart0(&line_dup, "#EXTINF:")) {

            bstr duration, btitle;

            if (bstr_split_tok(line_dup, ",", &duration, &btitle) && btitle.len) {

                talloc_free(title);

                title = bstrto0(NULL, btitle);

            }

        } else if (bstr_startswith0(line_dup, "#EXT-X-")) {

            // Note that this is only used for user advice. Actual HLS demuxing

            // must happen through demux_lavf.

            p->format = "hls";

        } else if (line_dup.len > 0 && !bstr_startswith0(line_dup, "#")) {

            pl_add(p, line);

            struct playlist_entry *e = playlist_get_last(p->pl);

            e->title = talloc_steal(e, title);

            title = NULL;

        }

        pl_free_line(p, line);

        line = pl_get_line(p);

    }

    pl_free_line(p, line);

    talloc_free(title);

    return 0;

}

static int parse_ref_init(struct pl_parser *p)

{

    bstr line = pl_get_line(p);

    if (!bstr_equals0(line, "[Reference]")) {

        pl_free_line(p, line);

        return -1;

    }

    pl_free_line(p, line);

    // ASF http streaming redirection - this is needed because ffmpeg http://

    // and mmsh:// can not automatically switch automatically between each

    // others. Both protocols use http - MMSH requires special http headers

    // to "activate" it, and will in other cases return this playlist.

    static const char *const mmsh_types[] = {"audio/x-ms-wax",

        "audio/x-ms-wma", "video/x-ms-asf", "video/x-ms-afs", "video/x-ms-wmv",

        "video/x-ms-wma", "application/x-mms-framed",

        "application/vnd.ms.wms-hdr.asfv1", NULL};

    bstr burl = bstr0(p->s->url);

    if (bstr_eatstart0(&burl, "http://") && check_mimetype(p->s, mmsh_types)) {

        MP_INFO(p, "Redirecting to mmsh://\n");

        playlist_append_file(p->pl, talloc_asprintf(p, "mmsh://%.*s", BSTR_P(burl)));

        return 0;

    }

    while (!pl_eof(p)) {

        line = pl_get_line(p);

        bstr value;

        if (bstr_case_startswith(line, bstr0("Ref"))) {

            bstr_split_tok(line, "=", &(bstr){0}, &value);

            if (value.len)

                pl_add(p, value);

        }

        pl_free_line(p, line);

    }

    return 0;

}

static int parse_ini_thing(struct pl_parser *p, const char *header,

                           const char *entry)

{

    bstr line = {0};

    while (!line.len && !pl_eof(p))

        line = pl_get_line(p);

    if (bstrcasecmp0(line, header) != 0) {

        pl_free_line(p, line);

        return -1;

    }

    if (p->probing) {

        pl_free_line(p, line);

        return 0;

    }

    pl_free_line(p, line);

    while (!pl_eof(p)) {

        line = pl_get_line(p);

        bstr key, value;

        if (bstr_split_tok(line, "=", &key, &value) &&

            bstr_case_startswith(key, bstr0(entry)))

        {

            value = bstr_strip(value);

            if (bstr_startswith0(value, "\"") && bstr_endswith0(value, "\""))

                value = bstr_splice(value, 1, -1);

            pl_add(p, value);

        }

        pl_free_line(p, line);

    }

    return 0;

}

static int parse_pls(struct pl_parser *p)

{

    return parse_ini_thing(p, "[playlist]", "File");

}

static int parse_url(struct pl_parser *p)

{

    return parse_ini_thing(p, "[InternetShortcut]", "URL");

}

static int parse_txt(struct pl_parser *p)

{

    if (!p->force)

        return -1;

    if (p->probing)

        return 0;

    MP_WARN(p, "Reading plaintext playlist.\n");

    while (!pl_eof(p)) {

        bstr line = pl_get_line(p);

        if (line.len == 0)

            continue;

        pl_add(p, line);

        pl_free_line(p, line);

    }

    return 0;

}

#define MAX_DIR_STACK 20

static bool same_st(struct stat *st1, struct stat *st2)

{

    return st1->st_dev == st2->st_dev && st1->st_ino == st2->st_ino;

}

struct pl_dir_entry {

    char *path;

    char *name;

    struct stat st;

    bool is_dir;

};

static int cmp_dir_entry(const void *a, const void *b)

{

    struct pl_dir_entry *a_entry = (struct pl_dir_entry*) a;

    struct pl_dir_entry *b_entry = (struct pl_dir_entry*) b;

    if (a_entry->is_dir == b_entry->is_dir) {

        return mp_natural_sort_cmp(a_entry->name, b_entry->name);

    } else {

        return a_entry->is_dir ? 1 : -1;

    }

}

static bool test_path(struct pl_parser *p, char *path, int autocreate)

{

    if (autocreate & AUTO_ANY)

        return true;

    if (!strcmp(path, p->real_stream->path))

        return true;

    bstr ext = mp_get_ext(bstr0(path));

    if (autocreate & AUTO_VIDEO && bstr_in_list0(ext, p->mp_opts->video_exts))

        return true;

    if (autocreate & AUTO_AUDIO && bstr_in_list0(ext, p->mp_opts->audio_exts))

        return true;

    if (autocreate & AUTO_IMAGE && bstr_in_list0(ext, p->mp_opts->image_exts))

        return true;

    if (autocreate & AUTO_ARCHIVE && bstr_in_list0(ext, p->mp_opts->archive_exts))

        return true;

    if (autocreate & AUTO_PLAYLIST && bstr_in_list0(ext, p->mp_opts->playlist_exts))

        return true;

    return false;

}

// Return true if this was a readable directory.

static bool scan_dir(struct pl_parser *p, char *path,

                     struct stat *dir_stack, int num_dir_stack, int autocreate)

{

    if (strlen(path) >= 8192 || num_dir_stack == MAX_DIR_STACK)

        return false; // things like mount bind loops

    DIR *dp = opendir(path);

    if (!dp) {

        MP_ERR(p, "Could not read directory.\n");

        return false;

    }

    struct pl_dir_entry *dir_entries = NULL;

    int num_dir_entries = 0;

    int path_len = strlen(path);

    int dir_mode = p->opts->dir_mode;

    struct dirent *ep;

    while ((ep = readdir(dp))) {

        if (ep->d_name[0] == '.')

            continue;

        if (mp_cancel_test(p->s->cancel))

            break;

        char *file = mp_path_join(p, path, ep->d_name);

        struct stat st;

        if (stat(file, &st) == 0 && S_ISDIR(st.st_mode)) {

            if (dir_mode != DIR_IGNORE) {

                for (int n = 0; n < num_dir_stack; n++) {

                    if (same_st(&dir_stack[n], &st)) {

                        MP_VERBOSE(p, "Skip recursive entry: %s\n", file);

                        goto skip;

                    }

                }

                struct pl_dir_entry d = {file, &file[path_len], st, true};

                MP_TARRAY_APPEND(p, dir_entries, num_dir_entries, d);

            }

        } else {

            struct pl_dir_entry f = {file, &file[path_len], .is_dir = false};

            MP_TARRAY_APPEND(p, dir_entries, num_dir_entries, f);

        }

        skip: ;

    }

    closedir(dp);

    if (dir_entries)

        qsort(dir_entries, num_dir_entries, sizeof(dir_entries[0]), cmp_dir_entry);

    for (int n = 0; n < num_dir_entries; n++) {

        char *file = dir_entries[n].path;

        if (dir_mode == DIR_RECURSIVE && dir_entries[n].is_dir) {

            dir_stack[num_dir_stack] = dir_entries[n].st;

            scan_dir(p, file, dir_stack, num_dir_stack + 1, autocreate);

        }

        else {

            if (dir_entries[n].is_dir || test_path(p, file, autocreate))

                playlist_append_file(p->pl, dir_entries[n].path);

        }

    }

    return true;

}

static enum autocreate_mode get_directory_filter(struct pl_parser *p)

{

    enum autocreate_mode autocreate = AUTO_NONE;

    if (!p->directory_filter || !p->directory_filter[0])

        autocreate = AUTO_ANY;

    if (bstr_in_list0(bstr0("video"), p->directory_filter))

        autocreate |= AUTO_VIDEO;

    if (bstr_in_list0(bstr0("audio"), p->directory_filter))

        autocreate |= AUTO_AUDIO;

    if (bstr_in_list0(bstr0("image"), p->directory_filter))

        autocreate |= AUTO_IMAGE;

    if (bstr_in_list0(bstr0("archive"), p->directory_filter))

        autocreate |= AUTO_ARCHIVE;

    if (bstr_in_list0(bstr0("playlist"), p->directory_filter))

        autocreate |= AUTO_PLAYLIST;

    return autocreate;

}

static int parse_dir(struct pl_parser *p)

{

    int ret = -1;

    struct stream *stream = p->real_stream;

    enum autocreate_mode autocreate = AUTO_NONE;

    p->pl->playlist_dir = NULL;

    if (p->autocreate_playlist && p->real_stream->is_local_fs && p->real_stream->is_regular &&

        !p->real_stream->is_directory) {

        bstr ext = mp_get_ext(bstr0(p->real_stream->url));

        switch (p->autocreate_playlist) {

        case 1: // filter

            autocreate = get_directory_filter(p);

            break;

        case 2: // same

            if (bstr_in_list0(ext, p->mp_opts->video_exts)) {

                autocreate = AUTO_VIDEO;

            } else if (bstr_in_list0(ext, p->mp_opts->audio_exts)) {

                autocreate = AUTO_AUDIO;

            } else if (bstr_in_list0(ext, p->mp_opts->image_exts)) {

                autocreate = AUTO_IMAGE;

            } else if (bstr_in_list0(ext, p->mp_opts->archive_exts)) {

                autocreate = AUTO_ARCHIVE;

            } else if (bstr_in_list0(ext, p->mp_opts->playlist_exts)) {

                autocreate = AUTO_PLAYLIST;

            }

            break;

        }

        int flags = STREAM_READ_FILE_FLAGS_DEFAULT;

        bstr dir = mp_dirname(p->real_stream->url);

        if (!dir.len)

            autocreate = AUTO_NONE;

        if (autocreate != AUTO_NONE) {

            stream = stream_create(bstrdup0(p, dir), flags, NULL, p->global);

            p->pl->playlist_dir = bstrdup0(p->pl, dir);

        }

    } else {

        autocreate = get_directory_filter(p);

    }

    if (!stream->is_directory)

        goto done;

    if (p->probing) {

        ret = 0;

        goto done;

    }

    char *path = mp_file_get_path(p, bstr0(stream->url));

    if (!path)

        goto done;

    if (autocreate == AUTO_NONE)

        goto done;

    struct stat dir_stack[MAX_DIR_STACK];

    if (p->opts->dir_mode == DIR_AUTO)

        p->opts->dir_mode = p->mp_opts->shuffle ? DIR_RECURSIVE : DIR_LAZY;

    scan_dir(p, path, dir_stack, 0, autocreate);

    ret = p->pl->num_entries > 0 ? 0 : -1;

done:

    if (stream != p->real_stream)

        free_stream(stream);

    return ret;

}

#define MIME_TYPES(...) \

    .mime_types = (const char*const[]){__VA_ARGS__, NULL}

struct pl_format {

    const char *name;

    int (*parse)(struct pl_parser *p);

    const char *const *mime_types;

};

static const struct pl_format dir_formats[] = {

    {"directory", parse_dir},

    {0},

};

static const struct pl_format playlist_formats[] = {

    {"m3u", parse_m3u,

     MIME_TYPES("audio/mpegurl", "audio/x-mpegurl", "application/x-mpegurl")},

    {"strm", parse_m3u},

    {"ini", parse_ref_init},

    {"pls", parse_pls,

     MIME_TYPES("audio/x-scpls")},

    {"url", parse_url},

    {"txt", parse_txt},

    {0},

};

static const struct pl_format *probe_pl(struct pl_parser *p, const struct pl_format *fmts)

{

    int64_t start = stream_tell(p->s);

    const struct pl_format *fmt = fmts;

    while (fmt->name) {

        stream_seek(p->s, start);

        if (check_mimetype(p->s, fmt->mime_types)) {

            MP_VERBOSE(p, "forcing format by mime-type.\n");

            p->force = true;

            return fmt;

        }

        if (fmt->parse(p) >= 0)

            return fmt;

        fmt++;

    }

    return NULL;

}

extern const demuxer_desc_t demuxer_desc_playlist;

extern const demuxer_desc_t demuxer_desc_directory;

static int open_file(struct demuxer *demuxer, enum demux_check check)

{

    if (!demuxer->access_references)

        return -1;

    bool force = check < DEMUX_CHECK_UNSAFE || check == DEMUX_CHECK_REQUEST;

    struct pl_parser *p = talloc_zero(NULL, struct pl_parser);

    p->global = demuxer->global;

    p->log = demuxer->log;

    p->pl = talloc_zero(p, struct playlist);

    p->real_stream = demuxer->stream;

    struct demux_opts *opts = mp_get_config_group(p, p->global, &demux_conf);

    p->codepage = opts->meta_cp;

    char probe[PROBE_SIZE];

    int probe_len = stream_read_peek(p->real_stream, probe, sizeof(probe));

    p->s = stream_memory_open(demuxer->global, probe, probe_len);

    p->s->mime_type = demuxer->stream->mime_type;

    p->utf16 = stream_skip_bom(p->s);

    p->force = force;

    p->check_level = check;

    p->probing = true;

    p->autocreate_playlist = demuxer->params->allow_playlist_create ? opts->autocreate_playlist : 0;

    p->directory_filter = opts->directory_filter;

    p->mp_opts = mp_get_config_group(demuxer, demuxer->global, &mp_opt_root);

    p->opts = mp_get_config_group(demuxer, demuxer->global, &demux_playlist_conf);

    const struct pl_format *fmts = playlist_formats;

    if (demuxer->desc == &demuxer_desc_directory)

        fmts = dir_formats;

    const struct pl_format *fmt = probe_pl(p, fmts);

    free_stream(p->s);

    playlist_clear(p->pl);

    if (!fmt) {

        talloc_free(p);

        return -1;

    }

    p->probing = false;

    p->error = false;

    p->s = demuxer->stream;

    p->utf16 = stream_skip_bom(p->s);

    bool ok = fmt->parse(p) >= 0 && !p->error;

    playlist_set_stream_flags(p->pl, demuxer->stream_origin);

    demuxer->playlist = talloc_steal(demuxer, p->pl);

    demuxer->filetype = p->format ? p->format : fmt->name;

    demuxer->fully_read = true;

    talloc_free(p);

    if (ok)

        demux_close_stream(demuxer);

    return ok ? 0 : -1;

}

const demuxer_desc_t demuxer_desc_directory = {

    .name = "directory",

    .desc = "Playlist dir",

    .open = open_file,

};

const demuxer_desc_t demuxer_desc_playlist = {

    .name = "playlist",

    .desc = "Playlist file",

    .open = open_file,

};