note
	description: "Tools to capture audio from a capturing audio device"
	author: "Louis Marchand"
	date: "Thu, 15 Jun 2017 19:17:55 +0000"
	revision: "0.1"

class 
	AUDIO_CAPTURE_CONTROLLER

create {AUDIO_LIBRARY_CONTROLLER}
	make

feature {NONE} -- Initialization

	default_create
			-- Process instances of classes with no creation clause.
			-- (Default: do nothing.)
			-- (from ANY)
		do
		end

	make (a_device: POINTER; a_frequency, a_channel_count, a_bits_per_sample, a_buffer_count: INTEGER_32)
			-- Initialization of Current using a_device as device, a_frequency as frequency
			-- a_channel_count as channel_count and a_bits_per_sample as bits_per_sample and a_buffer_count to initialize buffer
			-- and buffer_sample_count
		require
			device_valid: not a_device.is_default_pointer
			channel_valid: a_channel_count >= 1 and a_channel_count <= 2
			bits_per_sample_valid: a_bits_per_sample ~ 8 or a_bits_per_sample ~ 16
			frequency_valid: a_frequency > 0
		do
			device := a_device
			channel_count := a_channel_count
			frequency := a_frequency
			bits_per_sample := a_bits_per_sample
			buffer_sample_count := a_buffer_count
			create buffer.make (a_buffer_count * a_channel_count * (a_bits_per_sample // 8))
			is_device_closed := False
			is_capturing := False
			has_samples := False
			is_updating := False
		end
	
feature -- Access

	bits_per_sample: INTEGER_32
			-- The bit resolution of one frame of Current (without channel count).

	buffer: MANAGED_POINTER
			-- The data that has been read by update

	buffer_sample_count: INTEGER_32
			-- The number of samples that the buffer will be able to contain (for example,
			-- a stereo 16 bits capture with a buffer count of 1024 will have the size 1024*2*2 = 5096 bytes)

	channel_count: INTEGER_32
			-- The channel number of Current (1=mono, 2=stereo, etc.).

	frequency: INTEGER_32
			-- The frequency (sample rate) of Current.

	generating_type: TYPE [detachable AUDIO_CAPTURE_CONTROLLER]
			-- Type of current object
			-- (type of which it is a direct instance)
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			generating_type_not_void: Result /= Void
		end

	generator: STRING_8
			-- Name of current object's generating class
			-- (base class of the type of which it is a direct instance)
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			generator_not_void: Result /= Void
			generator_not_empty: not Result.is_empty
		end

	get_sample (a_index: INTEGER_32): LIST [INTEGER_16]
			-- Get the sample at the position a_index in the buffer (start at 1).
			-- The number of value in Result represent the channel_count
			-- If bits_per_sample is 8, the values are unsigned from 0 to 255 with 128 being an ouput level of 0
			-- If bits_per_sample is 16, the values are signed from -32768 to 32767 with 0 being an ouput level of 0
		require
			index_valid: a_index >= 1 and a_index <= buffer_sample_count
		local
			l_index: INTEGER_32
		do
			create {ARRAYED_LIST [INTEGER_16]} Result.make (channel_count)
			l_index := (a_index - 1) * channel_count
			if bits_per_sample ~ 16 then
				across
					l_index |..| (l_index + channel_count - 1) as la_index
				loop
					Result.extend (buffer.read_integer_16 (la_index.item))
				end
			else
				across
					l_index |..| (l_index + channel_count - 1) as la_index
				loop
					Result.extend (buffer.read_natural_8 (la_index.item).to_integer_16)
				end
			end
		ensure
			sample_count_valid: Result.count ~ channel_count
		end

	has_error: BOOLEAN
			-- Is the library has generate an error
			-- (from GAME_ERROR_MANAGER)

	has_samples: BOOLEAN
			-- Samples has been found by the last call to update

	is_capturing: BOOLEAN
			-- Current is presently capturing sound

	is_device_closed: BOOLEAN
			-- The capturing device id closed

	last_error: READABLE_STRING_GENERAL
			-- The last error generate by the library
			-- (from AUDIO_OPENAL_ERROR_MANAGER)
		do
			if is_manual_error then
				Result := Precursor {GAME_ERROR_MANAGER}
			elseif last_al_error_code /= {AUDIO_EXTERNAL}.al_no_error then
				if last_al_error_code = {AUDIO_EXTERNAL}.al_invalid_enum then
					Result := "An invalid enum value was passed to an OpenAL function."
				elseif last_al_error_code = {AUDIO_EXTERNAL}.al_invalid_value then
					Result := "An invalid value was passed to an OpenAL function."
				elseif last_al_error_code = {AUDIO_EXTERNAL}.al_invalid_operation then
					Result := "The requested operation is not valid."
				elseif last_al_error_code = {AUDIO_EXTERNAL}.al_invalid_name then
					Result := "A bad name (ID) was passed to an OpenAL function."
				elseif last_al_error_code = {AUDIO_EXTERNAL}.al_out_of_memory then
					Result := "The requested operation resulted in OpenAL running out of memory."
				else
					Result := "Unmanaged OpenAL error."
				end
			elseif last_alc_error_code /= {AUDIO_EXTERNAL}.alc_no_error then
				if last_alc_error_code = {AUDIO_EXTERNAL}.alc_invalid_value then
					Result := "An invalid value was passed to an OpenAL context function."
				elseif last_alc_error_code = {AUDIO_EXTERNAL}.alc_invalid_device then
					Result := "The device is not valid."
				elseif last_alc_error_code = {AUDIO_EXTERNAL}.alc_invalid_context then
					Result := "The context is not valid."
				elseif last_alc_error_code = {AUDIO_EXTERNAL}.alc_invalid_enum then
					Result := "Invalid enum parameter passed to an ALC call."
				elseif last_alc_error_code = {AUDIO_EXTERNAL}.alc_out_of_memory then
					Result := "Out of memory."
				else
					Result := "Unmanaged OpenAL context error."
				end
			else
				Result := "No error."
			end
		end

	start_capture
			-- Strart the capture (use update to fill the buffer)
		require
			device_open: not is_device_closed
			not_already_started: not is_capturing
		do
			clear_alc_error (device)
			{AUDIO_EXTERNAL}.alc_capture_start (device)
			read_alc_error (device, "Cannot start capture.")
			is_capturing := not has_error
		ensure
			capture_started: not has_error implies is_capturing
		end

	stop_capture
			-- Stop the capture
		require
			device_open: not is_device_closed
			not_already_stopped: is_capturing
		do
			clear_alc_error (device)
			{AUDIO_EXTERNAL}.alc_capture_stop (device)
			read_alc_error (device, "Cannot stop capture.")
			is_capturing := False
		ensure
			captue_stopped: not is_capturing
		end

	update
			-- Update a_buffer with the new value of the capture
		require
			device_open: not is_device_closed
			is_capturing: is_capturing
		do
			is_updating := True
			clear_alc_error (device)
			{AUDIO_EXTERNAL}.alc_capture_samples (device, buffer.item, buffer_sample_count)
			has_samples := True
			read_alc_error (device, "Cannot capture samples.")
			is_updating := False
		end
	
feature -- Comparison

	frozen deep_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void
			-- or attached to isomorphic object structures?
			-- (from ANY)
		do
			if a = Void then
				Result := b = Void
			else
				Result := b /= Void and then a.is_deep_equal (b)
			end
		ensure -- from ANY
			instance_free: class
			shallow_implies_deep: standard_equal (a, b) implies Result
			both_or_none_void: (a = Void) implies (Result = (b = Void))
			same_type: (Result and (a /= Void)) implies (b /= Void and then a.same_type (b))
			symmetric: Result implies deep_equal (b, a)
		end

	frozen equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached
			-- to objects considered equal?
			-- (from ANY)
		do
			if a = Void then
				Result := b = Void
			else
				Result := b /= Void and then a.is_equal (b)
			end
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.is_equal (b))
		end

	frozen is_deep_equal alias "≡≡≡" (other: AUDIO_CAPTURE_CONTROLLER): BOOLEAN
			-- Are Current and other attached to isomorphic object structures?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		external
			"built_in"
		ensure -- from ANY
			shallow_implies_deep: standard_is_equal (other) implies Result
			same_type: Result implies same_type (other)
			symmetric: Result implies other.is_deep_equal (Current)
		end

	is_equal (other: AUDIO_CAPTURE_CONTROLLER): BOOLEAN
			-- Is other attached to an object considered
			-- equal to current object?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		external
			"built_in"
		ensure -- from ANY
			symmetric: Result implies other ~ Current
			consistent: standard_is_equal (other) implies Result
		end

	frozen standard_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached to
			-- field-by-field identical objects of the same type?
			-- Always uses default object comparison criterion.
			-- (from ANY)
		do
			if a = Void then
				Result := b = Void
			else
				Result := b /= Void and then a.standard_is_equal (b)
			end
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.standard_is_equal (b))
		end

	frozen standard_is_equal alias "≜" (other: AUDIO_CAPTURE_CONTROLLER): BOOLEAN
			-- Is other attached to an object of the same type
			-- as current object, and field-by-field identical to it?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		external
			"built_in"
		ensure -- from ANY
			same_type: Result implies same_type (other)
			symmetric: Result implies other.standard_is_equal (Current)
		end
	
feature -- Status report

	conforms_to (other: ANY): BOOLEAN
			-- Does type of current object conform to type
			-- of other (as per Eiffel: The Language, chapter 13)?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		external
			"built_in"
		end

	same_type (other: ANY): BOOLEAN
			-- Is type of current object identical to type of other?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		external
			"built_in"
		ensure -- from ANY
			definition: Result = (conforms_to (other) and other.conforms_to (Current))
		end
	
feature -- Duplication

	frozen clone (other: detachable ANY): like other
		obsolete "Use `twin' instead. [2017-05-31]"
			-- Void if other is void; otherwise new object
			-- equal to other
			--
			-- For non-void other, clone calls copy;
			-- to change copying/cloning semantics, redefine copy.
			-- (from ANY)
		do
			if other /= Void then
				Result := other.twin
			end
		ensure -- from ANY
			instance_free: class
			equal: Result ~ other
		end

	copy (other: AUDIO_CAPTURE_CONTROLLER)
			-- Update current object using fields of object attached
			-- to other, so as to yield equal objects.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		external
			"built_in"
		ensure -- from ANY
			is_equal: Current ~ other
		end

	frozen deep_clone (other: detachable ANY): like other
		obsolete "Use `deep_twin' instead. [2017-05-31]"
			-- Void if other is void: otherwise, new object structure
			-- recursively duplicated from the one attached to other
			-- (from ANY)
		do
			if other /= Void then
				Result := other.deep_twin
			end
		ensure -- from ANY
			instance_free: class
			deep_equal: deep_equal (other, Result)
		end

	frozen deep_copy (other: AUDIO_CAPTURE_CONTROLLER)
			-- Effect equivalent to that of:
			--		copy (other . deep_twin)
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		do
			copy (other.deep_twin)
		ensure -- from ANY
			deep_equal: deep_equal (Current, other)
		end

	frozen deep_twin: AUDIO_CAPTURE_CONTROLLER
			-- New object structure recursively duplicated from Current.
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			deep_twin_not_void: Result /= Void
			deep_equal: deep_equal (Current, Result)
		end

	frozen standard_clone (other: detachable ANY): like other
		obsolete "Use `standard_twin' instead. [2017-05-31]"
			-- Void if other is void; otherwise new object
			-- field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		do
			if other /= Void then
				Result := other.standard_twin
			end
		ensure -- from ANY
			instance_free: class
			equal: standard_equal (Result, other)
		end

	frozen standard_copy (other: AUDIO_CAPTURE_CONTROLLER)
			-- Copy every field of other onto corresponding field
			-- of current object.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		external
			"built_in"
		ensure -- from ANY
			is_standard_equal: standard_is_equal (other)
		end

	frozen standard_twin: AUDIO_CAPTURE_CONTROLLER
			-- New object field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			standard_twin_not_void: Result /= Void
			equal: standard_equal (Result, Current)
		end

	frozen twin: AUDIO_CAPTURE_CONTROLLER
			-- New object equal to Current
			-- twin calls copy; to change copying/twinning semantics, redefine copy.
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result ~ Current
		end
	
feature -- Basic operations

	frozen as_attached: attached AUDIO_CAPTURE_CONTROLLER
		obsolete "Remove calls to this feature. [2017-05-31]"
			-- Attached version of Current.
			-- (Can be used during transitional period to convert
			-- non-void-safe classes to void-safe ones.)
			-- (from ANY)
		do
			Result := Current
		end

	frozen default: detachable AUDIO_CAPTURE_CONTROLLER
			-- Default value of object's type
			-- (from ANY)
		do
		end

	frozen default_pointer: POINTER
			-- Default value of type POINTER
			-- (Avoid the need to write p.default for
			-- some p of type POINTER.)
			-- (from ANY)
		do
		ensure -- from ANY
			instance_free: class
		end

	default_rescue
			-- Process exception for routines with no Rescue clause.
			-- (Default: do nothing.)
			-- (from ANY)
		do
		end

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)
		do
		ensure -- from ANY
			instance_free: class
		end
	
feature {AUDIO_ANY} -- Implementation

	device: POINTER
			-- Internal representation of the capture device
	
feature {AUDIO_LIBRARY_CONTROLLER} -- Implementation

	close_device
			-- Called when the AUDIO_LIBRARY_CONTROLLER close the capture device.
		do
			if is_capturing then
				stop_capture
			end
			is_device_closed := True
		end
	
feature {NONE} -- Implementation

	disable_print_on_error
			-- Desactive the print_on_error functionnality.
			-- (from GAME_ERROR_MANAGER)
		do
			Print_on_error_internal.put (False)
		end

	enable_print_on_error
			-- Active the print_on_error functionnality.
			-- (from GAME_ERROR_MANAGER)
		do
			Print_on_error_internal.put (True)
		end

	is_updating: BOOLEAN
			-- An update presently in progress

	manual_error: detachable READABLE_STRING_GENERAL
			-- The specific message for the last error
			-- (from GAME_ERROR_MANAGER)

	null: POINTER
			-- A NULL C pointer

	print_on_error: BOOLEAN
			-- When an error occured, the library will print
			-- informations about the error on the error console
			-- output (default is True).
			-- (from GAME_ERROR_MANAGER)
		do
			Result := Print_on_error_internal.item
		end

	Print_on_error_internal: CELL [BOOLEAN]
			-- True when an error occured,
			-- The library will print it right away.
			-- (from GAME_ERROR_MANAGER)
		once ("PROCESS")
			create Result.put (True)
		end

	read_alc_error (a_device: POINTER; a_message: READABLE_STRING_GENERAL)
			-- Read the next OpenAL error
		do
			last_al_error_code := {AUDIO_EXTERNAL}.al_no_error
			last_alc_error_code := {AUDIO_EXTERNAL}.alc_get_error (a_device)
			if is_updating and last_alc_error_code = {AUDIO_EXTERNAL}.alc_invalid_value then
				has_samples := False
			else
				has_error := last_alc_error_code /= {AUDIO_EXTERNAL}.alc_no_error
				if has_error and Print_on_error_internal.item then
					Io.Error.put_string (a_message.to_string_8 + "%N");
					Io.Error.put_string (last_error.to_string_8 + "%N")
				end
			end
		end

	set_print_on_error (a_value: BOOLEAN)
			-- Assign to print_on_error the value of a_value
			-- (from GAME_ERROR_MANAGER)
		do
			if a_value then
				enable_print_on_error
			else
				disable_print_on_error
			end
		ensure -- from GAME_ERROR_MANAGER
			is_assign: print_on_error ~ a_value
		end
	
feature {NONE} 

	clear_alc_error (a_device: POINTER)
			-- (from AUDIO_OPENAL_ERROR_MANAGER)
		do
			clear_error
			last_alc_error_code := {AUDIO_EXTERNAL}.alc_get_error (a_device)
		end

	clear_error
			-- Remove error pending in Current
			-- (from AUDIO_OPENAL_ERROR_MANAGER)
		do
			last_alc_error_code := {AUDIO_EXTERNAL}.alc_get_error (create {POINTER})
			last_al_error_code := {AUDIO_EXTERNAL}.al_get_error
			Precursor {GAME_ERROR_MANAGER}
		ensure -- from GAME_ERROR_MANAGER
			no_error: not has_error
		end

	is_error_managable: BOOLEAN
			-- Can the present error can be manage
			-- (from AUDIO_OPENAL_ERROR_MANAGER)
		do
			Result := last_al_error_code = {AUDIO_EXTERNAL}.al_out_of_memory or last_al_error_code = {AUDIO_EXTERNAL}.al_no_error
		end

	is_manual_error: BOOLEAN
			-- Is the present error a manual error
			-- (from AUDIO_OPENAL_ERROR_MANAGER)

	last_al_error_code: INTEGER_32
			-- The last error index return by the OpenAL library.
			-- (from AUDIO_OPENAL_ERROR_MANAGER)

	last_alc_error_code: INTEGER_32
			-- The last error index return by the OpenAL context library.
			-- (from AUDIO_OPENAL_ERROR_MANAGER)

	put_manual_error (a_general_message, a_specific_error: READABLE_STRING_GENERAL)
			-- Create a manual error using a_general_error for the debug information
			-- and a_specific_error for the lasting information
			-- (from AUDIO_OPENAL_ERROR_MANAGER)
		do
			last_al_error_code := {AUDIO_EXTERNAL}.al_no_error
			is_manual_error := True
			Precursor {GAME_ERROR_MANAGER} (a_general_message, a_specific_error)
		ensure -- from GAME_ERROR_MANAGER
				has_error
		end

	read_al_error (a_message: READABLE_STRING_GENERAL)
			-- Read the next OpenAL error
			-- (from AUDIO_OPENAL_ERROR_MANAGER)
		do
			last_alc_error_code := {AUDIO_EXTERNAL}.alc_no_error
			last_al_error_code := {AUDIO_EXTERNAL}.al_get_error
			has_error := last_al_error_code /= {AUDIO_EXTERNAL}.al_no_error
			if has_error and Print_on_error_internal.item then
				Io.Error.put_string (a_message.to_string_8 + "%N");
				Io.Error.put_string (last_error.to_string_8 + "%N")
			end
		end
	
feature -- Output

	Io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)
		once
			create Result;
			Result.set_output_default
		ensure -- from ANY
			instance_free: class
			io_not_void: Result /= Void
		end

	out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		do
			Result := tagged_out
		ensure -- from ANY
			out_not_void: Result /= Void
		end

	print (o: detachable ANY)
			-- Write terse external representation of o
			-- on standard output.
			-- (from ANY)
		local
			s: READABLE_STRING_8
		do
			if attached o then
				s := o.out
				if attached {READABLE_STRING_32} s as s32 then
					Io.put_string_32 (s32)
				elseif attached {READABLE_STRING_8} s as s8 then
					Io.put_string (s8)
				else
					Io.put_string_32 (s.as_string_32)
				end
			end
		ensure -- from ANY
			instance_free: class
		end

	frozen tagged_out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			tagged_out_not_void: Result /= Void
		end
	
feature -- Platform

	Operating_environment: OPERATING_ENVIRONMENT
			-- Objects available from the operating system
			-- (from ANY)
		once
			create Result
		ensure -- from ANY
			instance_free: class
			operating_environment_not_void: Result /= Void
		end
	
feature {NONE} -- Retrieval

	frozen internal_correct_mismatch
			-- Called from runtime to perform a proper dynamic dispatch on correct_mismatch
			-- from MISMATCH_CORRECTOR.
			-- (from ANY)
		local
			l_msg: STRING_32
			l_exc: EXCEPTIONS
		do
			if attached {MISMATCH_CORRECTOR} Current as l_corrector then
				l_corrector.correct_mismatch
			else
				create l_msg.make_from_string ("Mismatch: ".as_string_32)
				create l_exc;
				l_msg.append (generating_type.name_32);
				l_exc.raise_retrieval_exception (l_msg)
			end
		end
	
invariant
	buffer_count_valid: buffer.count ~ buffer_sample_count * channel_count * (bits_per_sample // 8)

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

end -- class AUDIO_CAPTURE_CONTROLLER

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