/*************************************************************************/
/*  audio_effect_filter.cpp                                              */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "audio_effect_filter.h"
#include "servers/audio_server.h"

template <int S>
void AudioEffectFilterInstance::_process_filter(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count) {
	for (int i = 0; i < p_frame_count; i++) {
		float f = p_src_frames[i].l;
		filter_process[0][0].process_one(f);
		if (S > 1) {
			filter_process[0][1].process_one(f);
		}
		if (S > 2) {
			filter_process[0][2].process_one(f);
		}
		if (S > 3) {
			filter_process[0][3].process_one(f);
		}

		p_dst_frames[i].l = f;
	}

	for (int i = 0; i < p_frame_count; i++) {
		float f = p_src_frames[i].r;
		filter_process[1][0].process_one(f);
		if (S > 1) {
			filter_process[1][1].process_one(f);
		}
		if (S > 2) {
			filter_process[1][2].process_one(f);
		}
		if (S > 3) {
			filter_process[1][3].process_one(f);
		}

		p_dst_frames[i].r = f;
	}
}

void AudioEffectFilterInstance::process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count) {
	filter.set_cutoff(base->cutoff);
	filter.set_gain(base->gain);
	filter.set_resonance(base->resonance);
	filter.set_mode(base->mode);
	int stages = int(base->db) + 1;
	filter.set_stages(stages);
	filter.set_sampling_rate(AudioServer::get_singleton()->get_mix_rate());

	for (int i = 0; i < 2; i++) {
		for (int j = 0; j < 4; j++) {
			filter_process[i][j].update_coeffs();
		}
	}

	if (stages == 1) {
		_process_filter<1>(p_src_frames, p_dst_frames, p_frame_count);
	} else if (stages == 2) {
		_process_filter<2>(p_src_frames, p_dst_frames, p_frame_count);
	} else if (stages == 3) {
		_process_filter<3>(p_src_frames, p_dst_frames, p_frame_count);
	} else if (stages == 4) {
		_process_filter<4>(p_src_frames, p_dst_frames, p_frame_count);
	}
}

AudioEffectFilterInstance::AudioEffectFilterInstance() {
	for (int i = 0; i < 2; i++) {
		for (int j = 0; j < 4; j++) {
			filter_process[i][j].set_filter(&filter);
		}
	}
}

Ref<AudioEffectInstance> AudioEffectFilter::instantiate() {
	Ref<AudioEffectFilterInstance> ins;
	ins.instantiate();
	ins->base = Ref<AudioEffectFilter>(this);

	return ins;
}

void AudioEffectFilter::set_cutoff(float p_freq) {
	cutoff = p_freq;
}

float AudioEffectFilter::get_cutoff() const {
	return cutoff;
}

void AudioEffectFilter::set_resonance(float p_amount) {
	resonance = p_amount;
}

float AudioEffectFilter::get_resonance() const {
	return resonance;
}

void AudioEffectFilter::set_gain(float p_amount) {
	gain = p_amount;
}

float AudioEffectFilter::get_gain() const {
	return gain;
}

void AudioEffectFilter::set_db(FilterDB p_db) {
	db = p_db;
}

AudioEffectFilter::FilterDB AudioEffectFilter::get_db() const {
	return db;
}

void AudioEffectFilter::_bind_methods() {
	ClassDB::bind_method(D_METHOD("set_cutoff", "freq"), &AudioEffectFilter::set_cutoff);
	ClassDB::bind_method(D_METHOD("get_cutoff"), &AudioEffectFilter::get_cutoff);

	ClassDB::bind_method(D_METHOD("set_resonance", "amount"), &AudioEffectFilter::set_resonance);
	ClassDB::bind_method(D_METHOD("get_resonance"), &AudioEffectFilter::get_resonance);

	ClassDB::bind_method(D_METHOD("set_gain", "amount"), &AudioEffectFilter::set_gain);
	ClassDB::bind_method(D_METHOD("get_gain"), &AudioEffectFilter::get_gain);

	ClassDB::bind_method(D_METHOD("set_db", "amount"), &AudioEffectFilter::set_db);
	ClassDB::bind_method(D_METHOD("get_db"), &AudioEffectFilter::get_db);

	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "cutoff_hz", PROPERTY_HINT_RANGE, "1,20500,1"), "set_cutoff", "get_cutoff");
	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "resonance", PROPERTY_HINT_RANGE, "0,1,0.01"), "set_resonance", "get_resonance");
	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "gain", PROPERTY_HINT_RANGE, "0,4,0.01"), "set_gain", "get_gain");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "db", PROPERTY_HINT_ENUM, "6 dB,12 dB,18 dB,24 dB"), "set_db", "get_db");

	BIND_ENUM_CONSTANT(FILTER_6DB);
	BIND_ENUM_CONSTANT(FILTER_12DB);
	BIND_ENUM_CONSTANT(FILTER_18DB);
	BIND_ENUM_CONSTANT(FILTER_24DB);
}

AudioEffectFilter::AudioEffectFilter(AudioFilterSW::Mode p_mode) {
	mode = p_mode;
	cutoff = 2000;
	resonance = 0.5;
	gain = 1.0;
	db = FILTER_6DB;
}