obs         = obslua

local hotkeys = {}
local hk = {}


function script_description()
	return [[Control audio source volumes with hotkeys.<br>Use Stream Deck + to control source volumes by using hotkeys]]
end
function script_properties()
	return false
end

function change_volume(source_name, type)
	local sources = obs.obs_enum_sources()
	if sources ~= nil then
		for _, source in ipairs(sources) do
			name = obs.obs_source_get_name(source)

			if name == source_name then
				local volume = obs.obs_source_get_volume(source)
				-- Convert volume to decibel
				local db = (20 * math.log10(volume))

				local change = 0.5
				if db <= -10 and db > -20 then
					change = 1
				elseif db <= -20  and db > -30 then
					change = 2
				elseif db <= -30  and db > -40 then
					change = 3
				elseif db <= -40  and db > -50 then
					change = 4
				elseif db <= -50 then
					change = 5
				else
					change = 0.5
				end

				if type == "up" then
					db = db + change
				else
					db = db - change
				end
				volume = (10^(db/20))

				if volume < 0 then
					volume = 0
				end
				if volume > 1 then
					volume = 1
				end
				obs.obs_source_set_volume(source, volume)
			end
		end
	end
end

function toggle_mute(source_name) 
	local sources = obs.obs_enum_sources()
	local state
	if sources ~= nil then
		for _, source in ipairs(sources) do
			name = obs.obs_source_get_name(source)

			if name == source_name then
				state = obs.obs_source_muted(source)
				if state == true then
					obs.obs_source_set_muted(source, false)
				else 
					obs.obs_source_set_muted(source, true)
				end
			end
		end
	end
end

-- A function named script_load will be called on startup
function script_load(settings)

	local sources = get_sources();
	local a

	local i = 0
	for k, v in pairs(sources) do
		
		hotkeys[i] = obs.OBS_INVALID_HOTKEY_ID
		
		-- Create volume up hotkey
		hk[i] = v..i
		hotkeys[i] = obs.obs_hotkey_register_frontend(hk[i], v .. " Vol +", function(pressed)
			if pressed then change_volume(v, "up") end
		end)

		a = obs.obs_data_get_array(settings, hk[i])
		obs.obs_hotkey_load(hotkeys[i], a)
		obs.obs_data_array_release(a)

		i = i + 1

		-- Create volume down hotkey
		hk[i] = v..i
		hotkeys[i] = obs.obs_hotkey_register_frontend(hk[i], v .. " Vol -", function(pressed)
			if pressed then change_volume(v, "down") end
		end)

		a = obs.obs_data_get_array(settings, hk[i])
		obs.obs_hotkey_load(hotkeys[i], a)
		obs.obs_data_array_release(a)

		i = i + 1

		-- Create volume mute toggle
		hk[i] = v..i
		hotkeys[i] = obs.obs_hotkey_register_frontend(hk[i], v .. " Toggle Mute", function(pressed)
			if pressed then toggle_mute(v) end
		end)

		a = obs.obs_data_get_array(settings, hk[i])
		obs.obs_hotkey_load(hotkeys[i], a)
		obs.obs_data_array_release(a)

		i = i + 1
		
	end

end

-- A function named script_save will be called when the script is saved
--
-- NOTE: This function is usually used for saving extra data (such as in this
-- case, a hotkey's save data).  Settings set via the properties are saved
-- automatically.
function script_save(settings)

	for k, v in pairs(hotkeys) do

		a = obs.obs_hotkey_save(hotkeys[k])
		obs.obs_data_set_array(settings, hk[k], a)
		obs.obs_data_array_release(a)
		
	end
end


function get_sources()

	local audio_sources = {}
	local sources = obs.obs_enum_sources()
	if sources ~= nil then
		for _, source in ipairs(sources) do

			source_id = obs.obs_source_get_id(source)
			local name = obs.obs_source_get_name(source)
			local fullname = name
			if source_id == "wasapi_output_capture" then
				fullname = name
				table.insert(audio_sources, fullname)
			elseif source_id == "wasapi_process_output_capture" then
				fullname = name
				table.insert(audio_sources, fullname)
			elseif source_id == "wasapi_input_capture" then
				fullname = name
				table.insert(audio_sources, fullname)
			end
		end
	end
	obs.source_list_release(sources)

	table.sort(audio_sources)
	local sources = {}
	local i = 0
	for _, k in pairs(audio_sources) do
		sources[i] = k
		i = i+1
	end

	return sources

end