// Copyright (c) 2010, Amar Takhar <verm@aegisub.org>
//
// Permission to use, copy, modify, and distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

/// @file mru.cpp
/// @brief Most Recently Used (MRU) Lists
/// @ingroup libaegisub

#include "libaegisub/mru.h"

#include "libaegisub/cajun/writer.h"

#include "libaegisub/io.h"
#include "libaegisub/json.h"
#include "libaegisub/log.h"
#include "libaegisub/option.h"
#include "libaegisub/option_value.h"

namespace agi {

MRUManager::MRUManager(agi::fs::path const& config, std::pair<const char *, size_t> default_config, agi::Options *options)
: config_name(config)
, options(options)
{
	option_names["Audio"] = "Limits/MRU";
	option_names["Keyframes"] = "Limits/MRU";
	option_names["Subtitle"] = "Limits/MRU";
	option_names["Timecodes"] = "Limits/MRU";
	option_names["Video"] = "Limits/MRU";

	option_names["Find"] = "Limits/Find Replace";
	option_names["Replace"] = "Limits/Find Replace";

	LOG_D("agi/mru") << "Loading MRU List";

	json::Object root(json_util::file(config, default_config));
	for (auto const& it : root)
		Load(it.first, it.second);
}

MRUManager::~MRUManager() {
}

MRUManager::MRUListMap &MRUManager::Find(std::string const& key) {
	auto index = mru.find(key);
	if (index == mru.end())
		throw MRUErrorInvalidKey("Invalid key value");
	return index->second;
}

void MRUManager::Add(std::string const& key, agi::fs::path const& entry) {
	MRUListMap &map = Find(key);
	auto it = find(begin(map), end(map), entry);
	if (it == begin(map) && it != end(map))
		return;
	if (it != end(map))
		map.splice(begin(map), map, it);
	else {
		map.push_front(entry);
		Prune(key, map);
	}

	Flush();
}

void MRUManager::Remove(std::string const& key, agi::fs::path const& entry) {
	Find(key).remove(entry);

	Flush();
}

const MRUManager::MRUListMap* MRUManager::Get(std::string const& key) {
	return &Find(key);
}

agi::fs::path const& MRUManager::GetEntry(std::string const& key, const size_t entry) {
	const MRUManager::MRUListMap *const map = Get(key);

	if (entry >= map->size())
		throw MRUErrorIndexOutOfRange("Requested element index is out of range.");

	return *next(map->begin(), entry);
}

void MRUManager::Flush() {
	json::Object out;

	for (auto const& mru_map : mru) {
		json::Array &array = out[mru_map.first];
		transform(begin(mru_map.second), end(mru_map.second),
			back_inserter(array), [](agi::fs::path const& p) { return p.string(); });
	}

	json::Writer::Write(out, io::Save(config_name).Get());
}

/// @brief Prune MRUListMap to the desired length.
/// This uses the user-set values for MRU list length.
void MRUManager::Prune(std::string const& key, MRUListMap& map) const {
	size_t limit = 16u;
	if (options) {
		auto it = option_names.find(key);
		if (it != option_names.end())
			limit = (size_t)options->Get(it->second)->GetInt();
	}
	map.resize(std::min(limit, map.size()));
}

/// @brief Load MRU Lists.
/// @param key List name.
/// @param array json::Array of values.
void MRUManager::Load(std::string const& key, const json::Array& array) {
	try {
		transform(begin(array), end(array),
			back_inserter(mru[key]), [](std::string const& s) { return s; });
	}
	catch (json::Exception const&) {
		// Out of date MRU file; just discard the data and skip it
	}
	Prune(key, mru[key]);
}

}