package cas.cs4tb3.mellowd.parser;
import cas.cs4tb3.mellowd.Dynamic;
import cas.cs4tb3.mellowd.TimingEnvironment;
import org.antlr.v4.runtime.Token;
import javax.sound.midi.InvalidMidiDataException;
import javax.sound.midi.Track;
import java.util.*;This is a state based class that is tracking the virtual state of the playback sequencer that help make decisions on which channel a channel specific event should happen on.
public class TrackManager {
public static class Channel {
public final boolean isDrum;
public final int midiChannelNum;
public final Set<Block> usedBy = new HashSet<>();
private Channel(boolean isDrum, int midiChannelNum) {
this.isDrum = isDrum;
this.midiChannelNum = midiChannelNum;
}
}
private Map<String, Block> blocks;
private Map<String, Channel> channelMap;
private List<Channel> channels;
private List<Channel> drumChannels;
public TrackManager(Set<Integer> regChannels, Set<Integer> drumChannels) {Check a few preconditions to make sure we have the expected channel inputs.
if (regChannels == null || regChannels.isEmpty())
throw new IllegalArgumentException("No regular channels specified.");
if (drumChannels == null || drumChannels.isEmpty())
throw new IllegalArgumentException("No drum channels specified.");
blocks = new HashMap<>();
this.channels = new ArrayList<>(regChannels.size());
this.drumChannels = new ArrayList<>(drumChannels.size());
for (int channel : regChannels) {
this.channels.add(new Channel(false, channel));
}
for (int dChannel : drumChannels) {
this.drumChannels.add(new Channel(true, dChannel));
}
this.channelMap = new HashMap<>();
this.blocks = new HashMap<>();
}
public Block createBlock(Token blockToken, TimingEnvironment timingEnvironment, Track track, BlockOptions options) {Check to make sure the block doesn’t exist yet
if (this.blocks.containsKey(blockToken.getText()))
throw new ParseException(blockToken, "A block with the name " + blockToken.getText() + " already exists.");Instantiate the new block
Block block = new Block(this, timingEnvironment, track, options, blockToken.getText(), Dynamic.mf);Register the block
this.blocks.put(block.getName(), block);Put it on a channel
requestChannel(block);
try {
block.updateBlockOptions(blockToken, options, true);
} catch (InvalidMidiDataException e) {
throw new ParseException(blockToken, "Invalid midi data in " + blockToken.getText() + "'s block options. "+e.getLocalizedMessage());
}Return the newly created block
return block;
}
public Block getBlock(String blockName) {
return this.blocks.get(blockName);
}
public void finish() {
for (Block block : this.blocks.values()) {
block.finish();
}
}
public void requestChannel(Block block) {
List<Channel> empties = new LinkedList<>();
if (block.getOptions().isPercussion()) {
for (Channel channel : drumChannels) {
if (channel.usedBy.isEmpty()) {Don’t take an empty channel yet because it would be better to share if possible.
empties.add(channel);
} else {
for (Block user : channel.usedBy) {
if (block.getName().equals(user.getOptions().getShareChannel())
|| user.getName().equals(block.getOptions().getShareChannel())) {Found a channel to share! We can pack these together.
switchChannels(channel, block);
return;
}
}
}
}
if (empties.isEmpty()) {Because this block is a percussion block it is not that bad if we have to share a channel.
switchChannels(drumChannels.get(0), block);
} else {Take the first empty channel.
switchChannels(empties.get(0), block);
}
} else {
Channel current = channelMap.get(block.getName());
if (current != null && !current.isDrum) return;
for (Channel channel : channels) {
if (channel.usedBy.isEmpty()) {Don’t take an empty channel yet because it would be better to share if possible.
empties.add(channel);
} else {
for (Block user : channel.usedBy) {
if (block.getName().equals(user.getOptions().getShareChannel())
|| user.getName().equals(block.getOptions().getShareChannel())) {Found a channel to share! We can pack these together.
switchChannels(channel, block);
return;
}
}
}
}
if (empties.isEmpty()) {Otherwise we really can’t just put 2 random regular blocks together because at the very least we may have an instrument mismatch. This is a problem we unfortunately cannot fix.
throw new IllegalStateException("Ran out of channels. Mellow D source is overloaded and cannot fit in the MIDI channels." +
" Try to use the \"sharechannel\" options to compact blocks on the same channel.");
} else {Take the first empty channel.
switchChannels(empties.get(0), block);
}
}
}
public String requestChannel(Block block, int channelNum) {
if (block.getOptions().isPercussion()) {
for (Channel channel : drumChannels) {
if (channel.midiChannelNum == channelNum) {Try and take this channel
if (channel.usedBy.isEmpty()) {
switchChannels(channel, block);
return null;
} else {
for (Block user : channel.usedBy) {
if (block.getName().equals(user.getOptions().getShareChannel())
|| user.getName().equals(block.getOptions().getShareChannel())) {The channel is occupied but a sharing relationship has been specified.
switchChannels(channel, block);
return null;
}
}
return "The requested channel (" + channelNum + ") is occupied by a block that does not allow sharing.";
}
}
}
return "The requested channel (" + channelNum + ") is not an available drum channel and the block (" + block.getName() + ") is a percussion block.";
} else {
for (Channel channel : channels) {
if (channel.midiChannelNum == channelNum) {Try and take this channel
if (channel.usedBy.isEmpty()) {
switchChannels(channel, block);
return null;
} else {
for (Block user : channel.usedBy) {
if (block.getName().equals(user.getOptions().getShareChannel())
|| user.getName().equals(block.getOptions().getShareChannel())) {The channel is occupied but a sharing relationship has been specified.
switchChannels(channel, block);
return null;
}
}
return "The requested channel (" + channelNum + ") is occupied by a block that does not allow sharing.";
}
}
}
return "The requested channel (" + channelNum + ") is not an available channel and the block (" + block.getName() + ") is a regular block.";
}
}
private void joinChannel(Channel channel, Block block) {
channel.usedBy.add(block);
this.channelMap.put(block.getName(), channel);
}
private void leaveChannel(Channel channel, Block block) {
channel.usedBy.remove(block);
this.channelMap.remove(block.getName());
}
private void switchChannels(Channel to, Block block) {
Channel from = channelMap.get(block.getName());
if (from != null) leaveChannel(from, block);
joinChannel(to, block);
}
public Channel getChannel(Block block) {
Channel channel = this.channelMap.get(block.getName());
if (channel != null)
return channel;
this.requestChannel(block);
return this.channelMap.get(block.getName());
}
}