wave-amp

--[[
wave-amp version 1.0.0

The MIT License (MIT)
Copyright (c) 2016 CrazedProgrammer

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
]]

--[[
wave version 0.1.4

The MIT License (MIT)
Copyright (c) 2016 CrazedProgrammer

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
]]

local wave = { }
wave.version = "0.1.4"

wave._oldSoundMap = {"harp", "bassattack", "bd", "snare", "hat"}
wave._newSoundMap = {"harp", "bass", "basedrum", "snare", "hat"}
wave._defaultThrottle = 99
wave._defaultClipMode = 1
wave._maxInterval = 1
wave._isNewSystem = false
if _HOST then
    wave._isNewSystem = _HOST:sub(15, #_HOST) >= "1.80"
end

wave.context = { }
wave.output = { }
wave.track = { }
wave.instance = { }

function wave.createContext(clock, volume)
    clock = clock or os.clock()
    volume = volume or 1.0

    local context = setmetatable({ }, {__index = wave.context})
    context.outputs = { }
    context.instances = { }
    context.vs = {0, 0, 0, 0, 0}
    context.prevClock = clock
    context.volume = volume
    return context
end

function wave.context:addOutput(...)
    local output = wave.createOutput(...)
    self.outputs[#self.outputs + 1] = output
    return output
end

function wave.context:addOutputs(...)
    local outs = {...}
    if #outs == 1 then
        if not getmetatable(outs) then
            outs = outs[1]
        else
            if getmetatable(outs).__index ~= wave.outputs then
                outs = outs[1]
            end
        end
    end
    for i = 1, #outs do
        self:addOutput(outs[i])
    end
end

function wave.context:removeOutput(out)
    if type(out) == "number" then
        table.remove(self.outputs, out)
        return
    elseif type(out) == "table" then
        if getmetatable(out).__index == wave.output then
            for i = 1, #self.outputs do
                if out == self.outputs[i] then
                    table.remove(self.outputs, i)
                    return
                end
            end
            return
        end
    end
    for i = 1, #self.outputs do
        if out == self.outputs[i].native then
            table.remove(self.outputs, i)
            return
        end
    end
end

function wave.context:addInstance(...)
    local instance = wave.createInstance(...)
    self.instances[#self.instances + 1] = instance
    return instance
end

function wave.context:removeInstance(instance)
    if type(instance) == "number" then
        table.remove(self.instances, instance)
    else
        for i = 1, #self.instances do
            if self.instances == instance then
                table.remove(self.instances, i)
                return
            end
        end
    end
end

function wave.context:playNote(note, pitch, volume)
    volume = volume or 1.0

    self.vs[note] = self.vs[note] + volume
    for i = 1, #self.outputs do
        self.outputs[i]:playNote(note, pitch, volume * self.volume)
    end
end

function wave.context:update(interval)
    local clock = os.clock()
    interval = interval or (clock - self.prevClock)

    self.prevClock = clock
    if interval > wave._maxInterval then
        interval = wave._maxInterval
    end
    for i = 1, #self.outputs do
        self.outputs[i].notes = 0
    end
    for i = 1, 5 do
        self.vs[i] = 0
    end
    if interval > 0 then
        for i = 1, #self.instances do
            local notes = self.instances[i]:update(interval)
            for j = 1, #notes / 3 do
                self:playNote(notes[j * 3 - 2], notes[j * 3 - 1], notes[j * 3])
            end
        end
    end
end



function wave.createOutput(out, volume, filter, throttle, clipMode)
    volume = volume or 1.0
    filter = filter or {true, true, true, true, true}
    throttle = throttle or wave._defaultThrottle
    clipMode = clipMode or wave._defaultClipMode

    local output = setmetatable({ }, {__index = wave.output})
    output.native = out
    output.volume = volume
    output.filter = filter
    output.notes = 0
    output.throttle = throttle
    output.clipMode = clipMode
    if type(out) == "function" then
        output.nativePlayNote = out
        output.type = "custom"
        return output
    elseif type(out) == "string" then
        if peripheral.getType(out) == "iron_noteblock" then
            if wave._isNewSystem then
                local nb = peripheral.wrap(out)
                output.type = "iron_noteblock"
                function output.nativePlayNote(note, pitch, volume)
                    if output.volume * volume > 0 then
                        nb.playSound("minecraft:block.note."..wave._newSoundMap[note], volume, math.pow(2, (pitch - 12) / 12))
                    end
                end
                return output
            end
        end
    elseif type(out) == "table" then
        if out.execAsync then
            output.type = "commands"
            if wave._isNewSystem then
                function output.nativePlayNote(note, pitch, volume)
                    out.execAsync("playsound minecraft:block.note."..wave._newSoundMap[note].." record @a ~ ~ ~ "..tostring(volume).." "..tostring(math.pow(2, (pitch - 12) / 12)))
                end
            else
                function output.nativePlayNote(note, pitch, volume)
                    out.execAsync("playsound note."..wave._oldSoundMap[note].." @a ~ ~ ~ "..tostring(volume).." "..tostring(math.pow(2, (pitch - 12) / 12)))
                end
            end
            return output
        elseif getmetatable(out) then
            if getmetatable(out).__index == wave.output then
                return out
            end
        end
    end
end

function wave.scanOutputs()
    local outs = { }
    if commands then
        outs[#outs + 1] = wave.createOutput(commands)
    end
    local sides = peripheral.getNames()
    for i = 1, #sides do
        if peripheral.getType(sides[i]) == "iron_noteblock" then
            outs[#outs + 1] = wave.createOutput(sides[i])
        end
    end
    return outs
end

function wave.output:playNote(note, pitch, volume)
    volume = volume or 1.0

    if self.clipMode == 1 then
        if pitch < 0 then
            pitch = 0
        elseif pitch > 24 then
            pitch = 24
        end
    elseif self.clipMode == 2 then
        if pitch < 0 then
            while pitch < 0 do
                pitch = pitch + 12
            end
        elseif pitch > 24 then
            while pitch > 24 do
                pitch = pitch - 12
            end
        end
    end
    if self.filter[note] and self.notes < self.throttle then
        self.nativePlayNote(note, pitch, volume * self.volume)
        self.notes = self.notes + 1
    end
end



function wave.loadTrack(path)
    local track = setmetatable({ }, {__index = wave.track})
    local handle = fs.open(path, "rb")
    if not handle then return end

    local function readInt(size)
        local num = 0
        for i = 0, size - 1 do
            local byte = handle.read()
            if not byte then -- dont leave open file handles no matter what
                handle.close()
                return
            end
            num = num + byte * (256 ^ i)
        end
        return num
    end
    local function readStr()
        local length = readInt(4)
        if not length then return end
        local data = { }
        for i = 1, length do
            data[i] = string.char(handle.read())
        end
        return table.concat(data)
    end

    -- Part #1: Metadata
    track.length = readInt(2) -- song length (ticks)
    track.height = readInt(2) -- song height
    track.name = readStr() -- song name
    track.author = readStr() -- song author
    track.originalAuthor = readStr() -- original song author
    track.description = readStr() -- song description
    track.tempo = readInt(2) / 100 -- tempo (ticks per second)
    track.autoSaving = readInt(1) == 0 and true or false -- auto-saving
    track.autoSavingDuration = readInt(1) -- auto-saving duration
    track.timeSignature = readInt(1) -- time signature (3 = 3/4)
    track.minutesSpent = readInt(4) -- minutes spent
    track.leftClicks = readInt(4) -- left clicks
    track.rightClicks = readInt(4) -- right clicks
    track.blocksAdded = readInt(4) -- blocks added
    track.blocksRemoved = readInt(4) -- blocks removed
    track.schematicFileName = readStr() -- midi/schematic file name

    -- Part #2: Notes
    track.layers = { }
    for i = 1, track.height do
        track.layers[i] = {name = "Layer "..i, volume = 1.0}
        track.layers[i].notes = { }
    end

    local tick = 0
    while true do
        local tickJumps = readInt(2)
        if tickJumps == 0 then break end
        tick = tick + tickJumps
        local layer = 0
        while true do
            local layerJumps = readInt(2)
            if layerJumps == 0 then break end
            layer = layer + layerJumps
            if layer > track.height then -- nbs can be buggy
                for i = track.height + 1, layer do
                    track.layers[i] = {name = "Layer "..i, volume = 1.0}
                    track.layers[i].notes = { }
                end
                track.height = layer
            end
            local instrument = readInt(1)
            local key = readInt(1)
            if instrument <= 4 then -- nbs can be buggy
                track.layers[layer].notes[tick * 2 - 1] = instrument + 1
                track.layers[layer].notes[tick * 2] = key - 33
            end
        end
    end

    -- Part #3: Layers
    for i = 1, track.height do
        local name = readStr()
        if not name then break end -- if layer data doesnt exist, abort
        track.layers[i].name = name
        track.layers[i].volume = readInt(1) / 100
    end

    handle.close()
    return track
end



function wave.createInstance(track, volume, playing, loop)
    volume = volume or 1.0
    playing = (playing == nil) or playing
    loop = (loop ~=  nil) and loop

    if getmetatable(track).__index == wave.instance then
        return track
    end
    local instance = setmetatable({ }, {__index = wave.instance})
    instance.track = track
    instance.volume = volume or 1.0
    instance.playing = playing
    instance.loop = loop
    instance.tick = 1
    return instance
end

function wave.instance:update(interval)
    local notes = { }
    if self.playing then
        local dticks = interval * self.track.tempo
        local starttick = self.tick
        local endtick = starttick + dticks
        local istarttick = math.ceil(starttick)
        local iendtick = math.ceil(endtick) - 1
        for i = istarttick, iendtick do
            for j = 1, self.track.height do
                if self.track.layers[j].notes[i * 2 - 1] then
                    notes[#notes + 1] = self.track.layers[j].notes[i * 2 - 1]
                    notes[#notes + 1] = self.track.layers[j].notes[i * 2]
                    notes[#notes + 1] = self.track.layers[j].volume
                end
            end
        end
        self.tick = self.tick + dticks

        if endtick > self.track.length then
            self.tick = 1
            self.playing = self.loop
        end
    end
    return notes
end



local cmdHelp = [[
-l                   lists all outputs connected to the computer.
-c <config file>     loads the parameters from a file.
parameters are separated by newlines.
-t <theme file>      loads the theme from a file.
-f <filter[:second]> sets the note filter for the outputs.
examples:
 -f 10111            sets the filter for all outputs to remove the bass instrument.
 -f 10011:01100      sets the filter so the bass and basedrum instruments only come out of the second output
-v <volume[:second]> sets the volume for the outputs.
--nrm --stp --rep --shf   sets the play mode.
--noui --noinput     disables the ui/keyboard input]]


local trackMode = 1
-- 1 = normal (go to next song on finish)
-- 2 = stop (stop on finish)
-- 3 = repeat (restart song on finish)
-- 4 = shuffle (go to random song on finish)

local files = { }
local tracks = { }
local context, track, instance

-- ui stuff
local noUI = false
local noInput = false
local screenWidth, screenHeight = term.getSize()
local trackScroll = 0
local currentTrack = 1
local vsEasings = {0, 0, 0, 0, 0}
local vsStep = 5
local vsDecline = 0.25

-- theme
local theme = term.isColor() and
{
    topBar = colors.lime,
    topBarTitle = colors.white,
    topBarOption = colors.white,
    topBarOptionSelected = colors.lightGray,
    topBarClose = colors.white,
    song = colors.black,
    songBackground = colors.white,
    songSelected = colors.black,
    songSelectedBackground = colors.lightGray,
    scrollBackground = colors.lightGray,
    scrollBar = colors.gray,
    scrollButton = colors.black,
    visualiserBar = colors.lime,
    visualiserBackground = colors.green,
    progressTime = colors.white,
    progressBackground = colors.lightGray,
    progressLine = colors.gray,
    progressNub = colors.gray,
    progressNubBackground = colors.gray,
    progressNubChar = "=",
    progressButton = colors.white
}
or
{
    topBar = colors.lightGray,
    topBarTitle = colors.white,
    topBarOption = colors.white,
    topBarOptionSelected = colors.gray,
    topBarClose = colors.white,
    song = colors.black,
    songBackground = colors.white,
    songSelected = colors.black,
    songSelectedBackground = colors.lightGray,
    scrollBackground = colors.lightGray,
    scrollBar = colors.gray,
    scrollButton = colors.black,
    visualiserBar = colors.black,
    visualiserBackground = colors.gray,
    progressTime = colors.white,
    progressBackground = colors.lightGray,
    progressLine = colors.gray,
    progressNub = colors.gray,
    progressNubBackground = colors.gray,
    progressNubChar = "=",
    progressButton = colors.white
}

local running = true



local function addFiles(path)
    local dirstack = {path}
    while #dirstack > 0 do
        local dir = dirstack[1]
        table.remove(dirstack, 1)
        if dir ~= "rom" then
            for _, v in pairs(fs.list(dir)) do
                local path = (dir == "") and v or dir.."/"..v
                if fs.isDir(path) then
                    dirstack[#dirstack + 1] = path
                elseif path:sub(#path - 3, #path) == ".nbs" then
                    files[#files + 1] = path
                end
            end
        end
    end
end

local function init(args)
    local volumes = { }
    local filters = { }
    local outputs = wave.scanOutputs()
    local timestamp = 0

    if #outputs == 0 then
        error("no outputs found")
    end

    local i, argtype = 1
    while i <= #args do
        if not argtype then
            if args[i] == "-h" then
                print(cmdHelp)
                noUI = true
                running = false
                return
            elseif args[i] == "-c" or args[i] == "-v" or args[i] == "-f" or args[i] == "-t" then
                argtype = args[i]
            elseif args[i] == "-l" then
                print(#outputs.." outputs detected:")
                for i = 1, #outputs do
                    print(i..":", outputs[i].type, type(outputs[i].native) == "string" and outputs[i].native or "")
                end
                noUI = true
                running = false
                return
            elseif args[i] == "--noui" then
                noUI = true
            elseif args[i] == "--noinput" then
                noInput = true
            elseif args[i] == "--nrm" then
                trackMode = 1
            elseif args[i] == "--stp" then
                trackMode = 2
            elseif args[i] == "--rep" then
                trackMode = 3
            elseif args[i] == "--shf" then
                trackMode = 4
            else
                local path = shell.resolve(args[i])
                if fs.isDir(path) then
                    addFiles(path)
                elseif fs.exists(path) then
                    files[#files + 1] = path
                end
            end
        else
            if argtype == "-c" then
                local path = shell.resolve(args[i])
                local handle = fs.open(path, "r")
                if not handle then
                    error("config file does not exist: "..path)
                end
                local line = handle.readLine()
                while line do
                    args[#args + 1] = line
                    line = handle.readLine()
                end
                handle.close()
            elseif argtype == "-t" then
                local path = shell.resolve(args[i])
                local handle = fs.open(path, "r")
                if not handle then
                    error("theme file does not exist: "..path)
                end
                local data = handle.readAll()
                handle.close()
                for k, v in pairs(colors) do
                    data = data:gsub("colors."..k, tostring(v))
                end
                for k, v in pairs(colours) do
                    data = data:gsub("colours."..k, tostring(v))
                end
                local newtheme = textutils.unserialize(data)
                for k, v in pairs(newtheme) do
                    theme[k] = v
                end
            elseif argtype == "-v" then
                for str in args[i]:gmatch("([^:]+)") do
                    local vol = tonumber(str)
                    if vol then
                        if vol >= 0 and vol <= 1 then
                            volumes[#volumes + 1] = vol
                        else
                            error("invalid volume value: "..str)
                        end
                    else
                        error("invalid volume value: "..str)
                    end
                end
            elseif argtype == "-f" then
                for str in args[i]:gmatch("([^:]+)") do
                    if #str == 5 then
                        local filter = { }
                        for i = 1, 5 do
                            if str:sub(i, i) == "1" then
                                filter[i] = true
                            elseif str:sub(i, i) == "0" then
                                filter[i] = false
                            else
                                error("invalid filter value: "..str)
                            end
                        end
                        filters[#filters + 1] = filter
                    else
                        error("invalid filter value: "..str)
                    end
                end
            end
            argtype = nil
        end
        i = i + 1
    end

    if #files == 0 then
        addFiles("")
    end

    i = 1
    print("loading tracks...")
    while i <= #files do
        local track
        pcall(function () track = wave.loadTrack(files[i]) end)
        if not track then
            print("failed to load "..files[i])
            os.sleep(0.2)
            table.remove(files, i)
        else
            tracks[i] = track
            print("loaded "..files[i])
            i = i + 1
        end
        if i % 10 == 0 then
            os.sleep(0)
        end
    end
    if #files == 0 then
        error("no tracks found")
    end

    if #volumes == 0 then
        volumes[1] = 1
    end
    if #filters == 0 then
        filters[1] = {true, true, true, true, true}
    end
    if #volumes == 1 then
        for i = 2, #outputs do
            volumes[i] = volumes[1]
        end
    end
    if #filters == 1 then
        for i = 2, #outputs do
            filters[i] = filters[1]
        end
    end
    if #volumes ~= #outputs then
        error("invalid amount of volume values: "..#volumes.." (must be 1 or "..#outputs..")")
    end
    if #filters ~= #outputs then
        error("invalid amount of filter values: "..#filters.." (must be 1 or "..#outputs..")")
    end

    for i = 1, #outputs do
        outputs[i].volume = volumes[i]
        outputs[i].filter = filters[i]
    end

    context = wave.createContext()
    context:addOutputs(outputs)
end




local function formatTime(secs)
    local mins = math.floor(secs / 60)
    secs = secs - mins * 60
    return string.format("%01d:%02d", mins, secs)
end

local function drawStatic()
    if noUI then return end
    term.setCursorPos(1, 1)
    term.setBackgroundColor(theme.topBar)
    term.setTextColor(theme.topBarTitle)
    term.write("wave-amp")
    term.write((" "):rep(screenWidth - 25))
    term.setTextColor(trackMode == 1 and theme.topBarOptionSelected or theme.topBarOption)
    term.write("nrm ")
    term.setTextColor(trackMode == 2 and theme.topBarOptionSelected or theme.topBarOption)
    term.write("stp ")
    term.setTextColor(trackMode == 3 and theme.topBarOptionSelected or theme.topBarOption)
    term.write("rep ")
    term.setTextColor(trackMode == 4 and theme.topBarOptionSelected or theme.topBarOption)
    term.write("shf ")
    term.setTextColor(theme.topBarClose)
    term.write("X")

    local scrollnub = math.floor(trackScroll / (#tracks - screenHeight + 7) * (screenHeight - 10) + 0.5)

    term.setTextColor(theme.song)
    term.setBackgroundColor(theme.songBackground)
    for i = 1, screenHeight - 7 do
        local index = i + trackScroll
        term.setCursorPos(1, i + 1)
        term.setTextColor(index == currentTrack and theme.songSelected or theme.song)
        term.setBackgroundColor(index == currentTrack and theme.songSelectedBackground or theme.songBackground)
        local str = ""
        if tracks[index] then
            local track = tracks[index]
            str = formatTime(track.length / track.tempo).." "
            if #track.name > 0 then
                str = str..(#track.originalAuthor == 0 and track.author or track.originalAuthor).." - "..track.name
            else
                local name = fs.getName(files[index])
                str = str..name:sub(1, #name - 4)
            end
        end
        if #str > screenWidth - 1 then
            str = str:sub(1, screenWidth - 3)..".."
        end
        term.write(str)
        term.write((" "):rep(screenWidth - 1 - #str))
        term.setBackgroundColor((i >= scrollnub + 1 and i <= scrollnub + 3) and theme.scrollBar or theme.scrollBackground)
        if i == 1 then
            term.setTextColor(theme.scrollButton)
            term.write(_HOST and "\30" or "^")
        elseif i == screenHeight - 7 then
            term.setTextColor(theme.scrollButton)
            term.write(_HOST and "\31" or "v")
        else
            term.write(" ")
        end
    end
end

local function drawDynamic()
    if noUI then return end
    for i = 1, 5 do
        vsEasings[i] = vsEasings[i] - vsDecline
        if vsEasings[i] < 0 then
            vsEasings[i] = 0
        end
        local part = context.vs[i] > vsStep and vsStep or context.vs[i]
        if vsEasings[i] < part then
            vsEasings[i] = part
        end
        local full = math.floor(part / vsStep * screenWidth + 0.5)
        local easing = math.floor(vsEasings[i] / vsStep * screenWidth + 0.5)
        term.setCursorPos(1, screenHeight - 6 + i)
        term.setBackgroundColor(theme.visualiserBar)
        term.setTextColor(theme.visualiserBackground)
        term.write((" "):rep(full))
        term.write((_HOST and "\127" or "#"):rep(math.floor((easing - full) / 2)))
        term.setBackgroundColor(theme.visualiserBackground)
        term.setTextColor(theme.visualiserBar)
        term.write((_HOST and "\127" or "#"):rep(math.ceil((easing - full) / 2)))
        term.write((" "):rep(screenWidth - easing))
    end

    local progressnub = math.floor((instance.tick / track.length) * (screenWidth - 14) + 0.5)

    term.setCursorPos(1, screenHeight)
    term.setTextColor(theme.progressTime)
    term.setBackgroundColor(theme.progressBackground)
    term.write(formatTime(instance.tick / track.tempo))

    term.setTextColor(theme.progressLine)
    term.write("\136")
    term.write(("\140"):rep(progressnub))
    term.setTextColor(theme.progressNub)
    term.setBackgroundColor(theme.progressNubBackground)
    term.write(theme.progressNubChar)
    term.setTextColor(theme.progressLine)
    term.setBackgroundColor(theme.progressBackground)
    term.write(("\140"):rep(screenWidth - 14 - progressnub))
    term.write("\132")

    term.setTextColor(theme.progressTime)
    term.write(formatTime(track.length / track.tempo).." ")
    term.setTextColor(theme.progressButton)
    term.write(instance.playing and (_HOST and "|\016" or "|>") or "||")
end

local function playSong(index)
    if index >= 1 and index <= #tracks then
        currentTrack = index
        track = tracks[currentTrack]
        context:removeInstance(1)
        instance = context:addInstance(track, 1, trackMode ~= 2, trackMode == 3)
        if currentTrack <= trackScroll then
            trackScroll = currentTrack - 1
        end
        if currentTrack > trackScroll + screenHeight - 7 then
            trackScroll = currentTrack - screenHeight + 7
        end
        drawStatic()
    end
end

local function nextSong()
    if trackMode == 1 then
        playSong(currentTrack + 1)
    elseif trackMode == 4 then
        playSong(math.random(#tracks))
    end
end

local function setScroll(scroll)
    trackScroll = scroll
    if trackScroll > #tracks - screenHeight + 7 then
        trackScroll = #tracks - screenHeight + 7
    end
    if trackScroll < 0 then
        trackScroll = 0
    end
    drawStatic()
end

local function handleClick(x, y)
    if noUI then return end
    if y == 1 then
        if x == screenWidth then
            running = false
        elseif x >= screenWidth - 16 and x <= screenWidth - 2 and (x - screenWidth + 1) % 4 ~= 0 then
            trackMode = math.floor((x - screenWidth + 16) / 4) + 1
            instance.loop = trackMode == 3
            drawStatic()
        end
    elseif x < screenWidth and y >= 2 and y <= screenHeight - 6 then
        playSong(y - 1 + trackScroll)
    elseif x == screenWidth and y == 2 then
        setScroll(trackScroll - 2)
    elseif x == screenWidth and y == screenHeight - 6 then
        setScroll(trackScroll + 2)
    elseif x == screenWidth and y >= 3 and y <= screenHeight - 7 then
        setScroll(math.floor((y - 3) / (screenHeight - 10) * (#tracks - screenHeight + 7 ) + 0.5))
    elseif y == screenHeight then
        if x >= screenWidth - 1 and x <= screenWidth then
            instance.playing = not instance.playing
        elseif x >= 6 and x <= screenWidth - 8 then
            instance.tick = ((x - 6) / (screenWidth - 14)) * track.length
        end
    end
end

local function handleScroll(x, y, scroll)
    if noUI then return end
    if y >= 2 and y <= screenHeight - 6 then
        setScroll(trackScroll + scroll * 2)
    end
end

local function handleKey(key)
    if noInput then return end
    if key == keys.space then
        instance.playing = not instance.playing
    elseif key == keys.n then
        nextSong()
    elseif key == keys.p then
        playSong(currentTrack - 1)
    elseif key == keys.m then
        context.volume = (context.volume == 0) and 1 or 0
    elseif key == keys.left then
        instance.tick = instance.tick - track.tempo * 10
        if instance.tick < 1 then
            instance.tick = 1
        end
    elseif key == keys.right then
        instance.tick = instance.tick + track.tempo * 10
    elseif key == keys.up then
        context.volume = (context.volume == 1) and 1 or context.volume + 0.1
    elseif key == keys.down then
        context.volume = (context.volume == 0) and 0 or context.volume - 0.1
    elseif key == keys.j then
        setScroll(trackScroll + 2)
    elseif key == keys.k then
        setScroll(trackScroll - 2)
    elseif key == keys.pageUp then
        setScroll(trackScroll - 5)
    elseif key == keys.pageDown then
        setScroll(trackScroll + 5)
    elseif key == keys.leftShift then
        trackMode = trackMode % 4 + 1
        drawStatic()
    elseif key == keys.backspace then
        running = false
    end
end

local function run()
    playSong(1)
    drawStatic()
    drawDynamic()
    local timer = os.startTimer(0.05)
    while running do
        local e = {os.pullEventRaw()}
        if e[1] == "timer" and e[2] == timer then
            timer = os.startTimer(0)
            local prevtick = instance.tick
            context:update()
            if prevtick > 1 and instance.tick == 1 then
                nextSong()
            end
            drawDynamic()
        elseif e[1] == "terminate" then
            running = false
        elseif e[1] == "term_resize" then
            screenWidth, screenHeight = term.getSize()
        elseif e[1] == "mouse_click" then
            handleClick(e[3], e[4])
        elseif e[1] == "mouse_scroll" then
            handleScroll(e[3], e[4], e[2])
        elseif e[1] == "key" then
            handleKey(e[2])
        end
    end
end

local function exit()
    if noUI then return end
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.setCursorPos(1, 1)
    term.clear()
end

init({...})
run()
exit()