// Copyright (c) 2005-2006, Rodrigo Braz Monteiro, Fredrik Mellbin
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//   * Neither the name of the Aegisub Group nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Aegisub Project http://www.aegisub.org/

#include "include/aegisub/audio_provider.h"

#include <libaegisub/make_unique.h>

#include <boost/algorithm/string/predicate.hpp>
#include <boost/filesystem/path.hpp>

/*
 * scheme            ::= "dummy-audio" ":" signal-specifier "?" signal-parameters
 * signal-specifier  ::= "silence" | "noise" | "sine" "/" frequency
 * frequency         ::= integer
 * signal-parameters ::= signal-parameter [ "&" signal-parameters ]
 * signal-parameter  ::= signal-parameter-name "=" integer
 * signal-parameter-name ::= "sr" | "bd" | "ch" | "ln"
 *
 * Signal types:
 * "silence", a silent signal is generated.
 * "noise", a white noise signal is generated.
 * "sine", a sine wave is generated at the specified frequency.
 *
 * Signal parameters:
 * "sr", sample rate to generate signal at.
 * "bd", bit depth to generate signal at (usually 16).
 * "ch", number of channels to generate, usually 1 or 2. The same signal is generated
 *       in every channel even if one would be LFE.
 * "ln", length of signal in samples. ln/sr gives signal length in seconds.
 */

namespace {
class DummyAudioProvider final : public AudioProvider {
	bool noise;
	void FillBuffer(void *buf, int64_t start, int64_t count) const override {
		if (noise) {
			auto workbuf = static_cast<uint16_t *>(buf);
			while (count-- > 0)
				*workbuf++ = (rand() - RAND_MAX/2) * 10000 / RAND_MAX;
		}
		else {
			memset(buf, 0, count * bytes_per_sample);
		}
	}

public:
	DummyAudioProvider(agi::fs::path const& uri) {
		noise = boost::contains(uri.string(), ":noise?");
		channels = 1;
		sample_rate = 44100;
		bytes_per_sample = 2;
		float_samples = false;
		decoded_samples = num_samples = (int64_t)5*30*60*1000 * sample_rate / 1000;
	}
};
}

std::unique_ptr<AudioProvider> CreateDummyAudioProvider(agi::fs::path const& file, agi::BackgroundRunner *) {
	if (!boost::starts_with(file.string(), "dummy-audio:"))
		return {};
	return agi::make_unique<DummyAudioProvider>(file);
}