/*
 * This file is part of mpv.
 *
 * mpv is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#if !HAVE_GPL
#error GPL only
#endif

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <strings.h>
#include <errno.h>
#include <assert.h>

#ifdef __linux__
#include <linux/cdrom.h>
#include <scsi/sg.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#endif

#include <dvdnav/dvdnav.h>
#include <libavutil/common.h>
#include <libavutil/intreadwrite.h>

#include "osdep/io.h"

#include "options/options.h"
#include "common/msg.h"
#include "input/input.h"
#include "options/m_config.h"
#include "options/path.h"
#include "osdep/timer.h"
#include "stream.h"
#include "demux/demux.h"
#include "video/out/vo.h"

#define TITLE_MENU -1
#define TITLE_LONGEST -2

struct priv {
    dvdnav_t *dvdnav;                   // handle to libdvdnav stuff
    char *filename;                     // path
    unsigned int duration;              // in milliseconds
    int mousex, mousey;
    int title;
    uint32_t spu_clut[16];
    bool spu_clut_valid;
    bool had_initial_vts;

    int dvd_speed;

    int track;
    char *device;

    struct dvd_opts *opts;
};

#define DNE(e) [e] = # e
static const char *const mp_dvdnav_events[] = {
    DNE(DVDNAV_BLOCK_OK),
    DNE(DVDNAV_NOP),
    DNE(DVDNAV_STILL_FRAME),
    DNE(DVDNAV_SPU_STREAM_CHANGE),
    DNE(DVDNAV_AUDIO_STREAM_CHANGE),
    DNE(DVDNAV_VTS_CHANGE),
    DNE(DVDNAV_CELL_CHANGE),
    DNE(DVDNAV_NAV_PACKET),
    DNE(DVDNAV_STOP),
    DNE(DVDNAV_HIGHLIGHT),
    DNE(DVDNAV_SPU_CLUT_CHANGE),
    DNE(DVDNAV_HOP_CHANNEL),
    DNE(DVDNAV_WAIT),
};

#define LOOKUP_NAME(array, i) \
    (((i) >= 0 && (i) < MP_ARRAY_SIZE(array)) ? array[(i)] : "?")

static void dvd_set_speed(stream_t *stream, char *device, unsigned speed)
{
#if defined(__linux__) && defined(SG_IO) && defined(GPCMD_SET_STREAMING)
  int fd;
  unsigned char buffer[28];
  unsigned char cmd[12];
  struct sg_io_hdr sghdr;
  struct stat st;

  memset(&st, 0, sizeof(st));

  if (stat(device, &st) == -1) return;

  if (!S_ISBLK(st.st_mode)) return; /* not a block device */

  switch (speed) {
  case 0: /* don't touch speed setting */
    return;
  case -1: /* restore default value */
    MP_INFO(stream, "Restoring DVD speed... ");
    break;
  default: /* limit to <speed> KB/s */
    // speed < 100 is multiple of DVD single speed (1350KB/s)
    if (speed < 100)
      speed *= 1350;
    MP_INFO(stream, "Limiting DVD speed to %dKB/s... ", speed);
    break;
  }

  memset(&sghdr, 0, sizeof(sghdr));
  sghdr.interface_id = 'S';
  sghdr.timeout = 5000;
  sghdr.dxfer_direction = SG_DXFER_TO_DEV;
  sghdr.dxfer_len = sizeof(buffer);
  sghdr.dxferp = buffer;
  sghdr.cmd_len = sizeof(cmd);
  sghdr.cmdp = cmd;

  memset(cmd, 0, sizeof(cmd));
  cmd[0] = GPCMD_SET_STREAMING;
  cmd[10] = sizeof(buffer);

  memset(buffer, 0, sizeof(buffer));
  /* first sector 0, last sector 0xffffffff */
  AV_WB32(buffer + 8, 0xffffffff);
  if (speed == -1)
    buffer[0] = 4; /* restore default */
  else {
    /* <speed> kilobyte */
    AV_WB32(buffer + 12, speed);
    AV_WB32(buffer + 20, speed);
  }
  /* 1 second */
  AV_WB16(buffer + 18, 1000);
  AV_WB16(buffer + 26, 1000);

  fd = open(device, O_RDWR | O_NONBLOCK | O_CLOEXEC);
  if (fd == -1) {
    MP_INFO(stream, "Couldn't open DVD device for writing, changing DVD speed needs write access.\n");
    return;
  }

  if (ioctl(fd, SG_IO, &sghdr) < 0)
    MP_INFO(stream, "failed\n");
  else
    MP_INFO(stream, "successful\n");

  close(fd);
#endif
}

// Check if this is likely to be an .ifo or similar file.
static int dvd_probe(const char *path, const char *ext, const char *sig)
{
    if (!bstr_case_endswith(bstr0(path), bstr0(ext)))
        return false;

    FILE *temp = fopen(path, "rb");
    if (!temp)
        return false;

    bool r = false;

    char data[50];

    assert(strlen(sig) <= sizeof(data));

    if (fread(data, 50, 1, temp) == 1) {
        if (memcmp(data, sig, strlen(sig)) == 0)
            r = true;
    }

    fclose(temp);
    return r;
}

static int fill_buffer(stream_t *s, char *buf, int max_len)
{
    struct priv *priv = s->priv;
    dvdnav_t *dvdnav = priv->dvdnav;

    if (max_len < 2048)
        return -1;

    while (1) {
        int len = -1;
        int event = DVDNAV_NOP;
        if (dvdnav_get_next_block(dvdnav, buf, &event, &len) != DVDNAV_STATUS_OK)
        {
            MP_ERR(s, "Error getting next block from DVD %d (%s)\n",
                   event, dvdnav_err_to_string(dvdnav));
            return 0;
        }
        if (event != DVDNAV_BLOCK_OK) {
            const char *name = LOOKUP_NAME(mp_dvdnav_events, event);
            MP_VERBOSE(s, "DVDNAV: event %s (%d).\n", name, event);
        }
        switch (event) {
        case DVDNAV_BLOCK_OK:
            return len;
        case DVDNAV_STOP:
            return 0;
        case DVDNAV_NAV_PACKET: {
            pci_t *pnavpci = dvdnav_get_current_nav_pci(dvdnav);
            uint32_t start_pts = pnavpci->pci_gi.vobu_s_ptm;
            MP_TRACE(s, "start pts = %"PRIu32"\n", start_pts);
            break;
        }
        case DVDNAV_STILL_FRAME:
            dvdnav_still_skip(dvdnav);
            return 0;
        case DVDNAV_WAIT:
            dvdnav_wait_skip(dvdnav);
            return 0;
        case DVDNAV_HIGHLIGHT:
            break;
        case DVDNAV_VTS_CHANGE: {
            int tit = 0, part = 0;
            dvdnav_vts_change_event_t *vts_event =
                (dvdnav_vts_change_event_t *)s->buffer;
            MP_INFO(s, "DVDNAV, switched to title: %d\n",
                   vts_event->new_vtsN);
            if (!priv->had_initial_vts) {
                // dvdnav sends an initial VTS change before any data; don't
                // cause a blocking wait for the player, because the player in
                // turn can't initialize the demuxer without data.
                priv->had_initial_vts = true;
                break;
            }
            if (dvdnav_current_title_info(dvdnav, &tit, &part) == DVDNAV_STATUS_OK)
            {
                MP_VERBOSE(s, "DVDNAV, NEW TITLE %d\n", tit);
                if (priv->title > 0 && tit != priv->title)
                    MP_WARN(s, "Requested title not found\n");
            }
            break;
        }
        case DVDNAV_CELL_CHANGE: {
            dvdnav_cell_change_event_t *ev =  (dvdnav_cell_change_event_t *)buf;

            if (ev->pgc_length)
                priv->duration = ev->pgc_length / 90;

            break;
        }
        case DVDNAV_SPU_CLUT_CHANGE: {
            memcpy(priv->spu_clut, buf, 16 * sizeof(uint32_t));
            priv->spu_clut_valid = true;
            break;
        }
        }
    }
    return 0;
}

static int control(stream_t *stream, int cmd, void *arg)
{
    struct priv *priv = stream->priv;
    dvdnav_t *dvdnav = priv->dvdnav;

    switch (cmd) {
    case STREAM_CTRL_OPTICAL_CRAP_HACK1: {
        if (priv->duration) {
            *(double *)arg = (double)priv->duration / 1000.0;
            return 1;
        }
        break;
    }
    case STREAM_CTRL_OPTICAL_CRAP_HACK2: {
        double *args = arg;
        double d = args[0]; // absolute target timestamp
        int flags = args[1]; // from SEEK_* flags (demux.h)
        if (flags & SEEK_HR)
            d -= 10; // fudge offset; it's a hack, because fuck libdvd*
        int64_t tm = (int64_t)(d * 90000);
        if (tm < 0)
            tm = 0;
        if (priv->duration && tm >= (priv->duration * 90))
            tm = priv->duration * 90 - 1;
        uint32_t pos, len;
        if (dvdnav_get_position(dvdnav, &pos, &len) != DVDNAV_STATUS_OK)
            break;
        MP_VERBOSE(stream, "seek to PTS %f (%"PRId64")\n", d, tm);
        if (dvdnav_time_search(dvdnav, tm) != DVDNAV_STATUS_OK)
            break;
        stream_drop_buffers(stream);
        d = dvdnav_get_current_time(dvdnav) / 90000.0f;
        MP_VERBOSE(stream, "landed at: %f\n", d);
        if (dvdnav_get_position(dvdnav, &pos, &len) == DVDNAV_STATUS_OK)
            MP_VERBOSE(stream, "block: %lu\n", (unsigned long)pos);
        return STREAM_OK;
    }
    }

    return STREAM_UNSUPPORTED;
}

static void stream_dvdnav_close(stream_t *s)
{
    struct priv *priv = s->priv;
    dvdnav_close(priv->dvdnav);
    priv->dvdnav = NULL;
    if (priv->dvd_speed)
        dvd_set_speed(s, priv->filename, -1);
    if (priv->filename)
        free(priv->filename);
}

static struct priv *new_dvdnav_stream(stream_t *stream, char *filename)
{
    struct priv *priv = stream->priv;
    const char *title_str;

    if (!filename)
        return NULL;

    if (!(priv->filename = strdup(filename)))
        return NULL;

    priv->dvd_speed = priv->opts->speed;
    dvd_set_speed(stream, priv->filename, priv->dvd_speed);

    if (dvdnav_open(&(priv->dvdnav), priv->filename) != DVDNAV_STATUS_OK) {
        free(priv->filename);
        priv->filename = NULL;
        return NULL;
    }

    if (!priv->dvdnav)
        return NULL;

    dvdnav_set_readahead_flag(priv->dvdnav, 1);
    if (dvdnav_set_PGC_positioning_flag(priv->dvdnav, 1) != DVDNAV_STATUS_OK)
        MP_ERR(stream, "stream_dvdnav, failed to set PGC positioning\n");
    /* report the title?! */
    dvdnav_get_title_string(priv->dvdnav, &title_str);

    return priv;
}

static int open_s_internal(stream_t *stream)
{
    struct priv *priv, *p;
    priv = p = stream->priv;
    char *filename;

    p->opts = mp_get_config_group(stream, stream->global, &dvd_conf);

    if (p->device && p->device[0])
        filename = p->device;
    else if (p->opts->device && p->opts->device[0])
        filename = p->opts->device;
    else
        filename = DEFAULT_DVD_DEVICE;
    if (!new_dvdnav_stream(stream, filename)) {
        MP_ERR(stream, "Couldn't open DVD device: %s\n",
                filename);
        return STREAM_UNSUPPORTED;
    }

    if (p->track == TITLE_LONGEST) { // longest
        dvdnav_t *dvdnav = priv->dvdnav;
        uint64_t best_length = 0;
        int best_title = -1;
        int32_t num_titles;
        if (dvdnav_get_number_of_titles(dvdnav, &num_titles) == DVDNAV_STATUS_OK) {
            MP_VERBOSE(stream, "List of available titles:\n");
            for (int n = 1; n <= num_titles; n++) {
                uint64_t *parts = NULL, duration = 0;
                dvdnav_describe_title_chapters(dvdnav, n, &parts, &duration);
                if (parts) {
                    if (duration > best_length) {
                        best_length = duration;
                        best_title = n;
                    }
                    if (duration > 90000) { // arbitrarily ignore <1s titles
                        char *time = mp_format_time(duration / 90000, false);
                        MP_VERBOSE(stream, "title: %3d duration: %s\n",
                                   n - 1, time);
                        talloc_free(time);
                    }
                    free(parts);
                }
            }
        }
        p->track = best_title - 1;
        MP_INFO(stream, "Selecting title %d.\n", p->track);
    }

    if (p->track >= 0) {
        priv->title = p->track;
        if (dvdnav_title_play(priv->dvdnav, p->track + 1) != DVDNAV_STATUS_OK) {
            MP_FATAL(stream, "dvdnav_stream, couldn't select title %d, error '%s'\n",
                   p->track, dvdnav_err_to_string(priv->dvdnav));
            return STREAM_UNSUPPORTED;
        }
    } else {
        MP_FATAL(stream, "DVD menu support has been removed.\n");
        return STREAM_ERROR;
    }
    if (p->opts->angle > 1)
        dvdnav_angle_change(priv->dvdnav, p->opts->angle);

    stream->fill_buffer = fill_buffer;
    stream->control = control;
    stream->close = stream_dvdnav_close;
    stream->lavf_type = "mpeg";

    return STREAM_OK;
}

static int open_s(stream_t *stream)
{
    struct priv *priv = talloc_zero(stream, struct priv);
    stream->priv = priv;

    bstr title, bdevice;
    bstr_split_tok(bstr0(stream->path), "/", &title, &bdevice);

    priv->track = TITLE_LONGEST;

    if (bstr_equals0(title, "longest") || bstr_equals0(title, "first")) {
        priv->track = TITLE_LONGEST;
    } else if (bstr_equals0(title, "menu")) {
        priv->track = TITLE_MENU;
    } else if (title.len) {
        bstr rest;
        priv->track = bstrtoll(title, &rest, 10);
        if (rest.len) {
            MP_ERR(stream, "number expected: '%.*s'\n", BSTR_P(rest));
            return STREAM_ERROR;
        }
    }

    priv->device = bstrto0(priv, bdevice);

    return open_s_internal(stream);
}

const stream_info_t stream_info_dvdnav = {
    .name = "dvdnav",
    .open = open_s,
    .protocols = (const char*const[]){ "dvd", "dvdnav", NULL },
};

static bool check_ifo(const char *path)
{
    if (strcasecmp(mp_basename(path), "video_ts.ifo"))
        return false;

    return dvd_probe(path, ".ifo", "DVDVIDEO-VMG");
}

static int ifo_dvdnav_stream_open(stream_t *stream)
{
    struct priv *priv = talloc_zero(stream, struct priv);
    stream->priv = priv;

    if (!stream->access_references)
        goto unsupported;

    priv->track = TITLE_LONGEST;

    char *path = mp_file_get_path(priv, bstr0(stream->url));
    if (!path)
        goto unsupported;

    // We allow the path to point to a directory containing VIDEO_TS/, a
    // directory containing VIDEO_TS.IFO, or that file itself.
    if (!check_ifo(path)) {
        // On UNIX, just assume the filename is always uppercase.
        char *npath = mp_path_join(priv, path, "VIDEO_TS.IFO");
        if (!check_ifo(npath)) {
            npath = mp_path_join(priv, path, "VIDEO_TS/VIDEO_TS.IFO");
            if (!check_ifo(npath))
                goto unsupported;
        }
        path = npath;
    }

    priv->device = bstrto0(priv, mp_dirname(path));

    MP_INFO(stream, ".IFO detected. Redirecting to dvd://\n");
    return open_s_internal(stream);

unsupported:
    talloc_free(priv);
    stream->priv = NULL;
    return STREAM_UNSUPPORTED;
}

const stream_info_t stream_info_ifo_dvdnav = {
    .name = "ifo_dvdnav",
    .open = ifo_dvdnav_stream_open,
    .protocols = (const char*const[]){ "file", "", NULL },
};