#!/usr/bin/env python3
#
# vidi-player - generate GStreamer Editing Services timelines from midi
#
# Copyright (C) 2016  Antonio Ospite <ao2@ao2.it>
#
# This program 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 3 of the License, or
# (at your option) any later version.
#
# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

import os
import sys
import mido
import vidi


def is_note(msg):
    return msg.type == 'note_on' or msg.type == 'note_off'


def is_note_on(msg):
    return msg.type == 'note_on' and msg.velocity > 0


def is_note_off(msg):
    return ((msg.type == 'note_on' and msg.velocity == 0) or
            (msg.type == 'note_off'))


def check_overlapping_notes(midi_file):
    previous_note_on = False
    for msg in midi_file:
        if is_note_on(msg) and msg.channel == 0:
            if previous_note_on:
                return True

            previous_note_on = True
        elif is_note_off(msg) and msg.channel == 0:
            previous_note_on = False

    return False


def timeline_from_midi(midi_file, video_font_path):
    timeline = vidi.Timeline()

    elapsed_time = 0
    start_time = 0
    for msg in midi_file:
        elapsed_time += msg.time
        if is_note_on(msg) and msg.channel == 0:
            start_time = elapsed_time
        elif is_note_off(msg) and msg.channel == 0:
            note = vidi.MidiNote(msg.note)
            duration = elapsed_time - start_time
            print("Note name: %s start_time: %f duration: %f" %
                  (note.name, start_time, duration))

            video_sample_path = "%s/sample_%s.mkv" % (video_font_path, note.name)

            timeline.add_clip(video_sample_path, start_time, duration)

    return timeline


def usage():
    print("usage: %s <midi_file> <videofont_directory> [<destination_file>]"
          % os.path.basename(sys.argv[0]))


def main():
    if len(sys.argv) > 1 and sys.argv[1] in ["-h", "--help"]:
        usage()
        return 0

    if len(sys.argv) < 3:
        usage()
        return 1

    if not os.path.isdir(sys.argv[2]):
        sys.stderr.write("The second argument must be the path of the videofont directory\n")
        usage()
        return 1

    if len(sys.argv) > 3 and os.path.exists(sys.argv[3]):
        sys.stderr.write("File '%s' exists, exiting!\n" % sys.argv[3])
        return 1

    midi_file = mido.MidiFile(sys.argv[1])

    overlapping_notes = check_overlapping_notes(midi_file, 0)
    if overlapping_notes:
        sys.stderr.write("Sorry, supporting only midi file with no overlapping notes on channel 0\n")
        return 1

    video_font_path = os.path.realpath(sys.argv[2])

    timeline = timeline_from_midi(midi_file, video_font_path)

    if len(sys.argv) > 3:
        timeline.save(sys.argv[3])
    else:
        try:
            timeline.play()
        except KeyboardInterrupt:
            timeline.stop()
            return 1


if __name__ == "__main__":
    sys.exit(main())