/*
	This file is part of solidity.

	solidity is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	solidity is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
*/
// SPDX-License-Identifier: GPL-3.0

#include <libsolidity/lsp/FileRepository.h>
#include <libsolidity/lsp/Utils.h>

#include <libsolutil/StringUtils.h>
#include <libsolutil/CommonIO.h>

#include <range/v3/range/conversion.hpp>
#include <range/v3/view/transform.hpp>

#include <regex>

using namespace std;
using namespace solidity;
using namespace solidity::lsp;
using namespace solidity::frontend;

using solidity::util::readFileAsString;
using solidity::util::joinHumanReadable;

FileRepository::FileRepository(boost::filesystem::path _basePath): m_basePath(std::move(_basePath))
{
}

string FileRepository::sourceUnitNameToUri(string const& _sourceUnitName) const
{
	regex const windowsDriveLetterPath("^[a-zA-Z]:/");

	if (m_sourceUnitNamesToUri.count(_sourceUnitName))
		return m_sourceUnitNamesToUri.at(_sourceUnitName);
	else if (_sourceUnitName.find("file://") == 0)
		return _sourceUnitName;
	else if (regex_search(_sourceUnitName, windowsDriveLetterPath))
		return "file:///" + _sourceUnitName;
	else if (_sourceUnitName.find("/") == 0)
		return "file://" + _sourceUnitName;
	else
		return "file://" + m_basePath.generic_string() + "/" + _sourceUnitName;
}

string FileRepository::uriToSourceUnitName(string const& _path) const
{
	return stripFileUriSchemePrefix(_path);
}

void FileRepository::setSourceByUri(string const& _uri, string _source)
{
	// This is needed for uris outside the base path. It can lead to collisions,
	// but we need to mostly rewrite this in a future version anyway.
	auto sourceUnitName = uriToSourceUnitName(_uri);
	m_sourceUnitNamesToUri.emplace(sourceUnitName, _uri);
	m_sourceCodes[sourceUnitName] = std::move(_source);
}

frontend::ReadCallback::Result FileRepository::readFile(string const& _kind, string const& _sourceUnitName)
{
	solAssert(
		_kind == ReadCallback::kindString(ReadCallback::Kind::ReadFile),
		"ReadFile callback used as callback kind " + _kind
	);

	try
	{
		// File was read already. Use local store.
		if (m_sourceCodes.count(_sourceUnitName))
			return ReadCallback::Result{true, m_sourceCodes.at(_sourceUnitName)};

		string const strippedSourceUnitName = stripFileUriSchemePrefix(_sourceUnitName);

		if (
			boost::filesystem::path(strippedSourceUnitName).has_root_path() &&
			boost::filesystem::exists(strippedSourceUnitName)
		)
		{
			auto contents = readFileAsString(strippedSourceUnitName);
			solAssert(m_sourceCodes.count(_sourceUnitName) == 0, "");
			m_sourceCodes[_sourceUnitName] = contents;
			return ReadCallback::Result{true, move(contents)};
		}

		vector<boost::filesystem::path> candidates;
		vector<reference_wrapper<boost::filesystem::path>> prefixes = {m_basePath};
		prefixes += (m_includePaths | ranges::to<vector<reference_wrapper<boost::filesystem::path>>>);

		auto const pathToQuotedString = [](boost::filesystem::path const& _path) { return "\"" + _path.string() + "\""; };

		for (auto const& prefix: prefixes)
		{
			boost::filesystem::path canonicalPath = boost::filesystem::path(prefix) / boost::filesystem::path(strippedSourceUnitName);

			if (boost::filesystem::exists(canonicalPath))
				candidates.push_back(move(canonicalPath));
		}

		if (candidates.empty())
			return ReadCallback::Result{
				false,
				"File not found. Searched the following locations: " +
				joinHumanReadable(prefixes | ranges::views::transform(pathToQuotedString), ", ") +
				"."
			};

		if (candidates.size() >= 2)
			return ReadCallback::Result{
				false,
				"Ambiguous import. "
				"Multiple matching files found inside base path and/or include paths: " +
				joinHumanReadable(candidates | ranges::views::transform(pathToQuotedString), ", ") +
				"."
			};

		if (!boost::filesystem::is_regular_file(candidates[0]))
			return ReadCallback::Result{false, "Not a valid file."};

		auto contents = readFileAsString(candidates[0]);
		solAssert(m_sourceCodes.count(_sourceUnitName) == 0, "");
		m_sourceCodes[_sourceUnitName] = contents;
		return ReadCallback::Result{true, move(contents)};
	}
	catch (std::exception const& _exception)
	{
		return ReadCallback::Result{false, "Exception in read callback: " + boost::diagnostic_information(_exception)};
	}
	catch (...)
	{
		return ReadCallback::Result{false, "Unknown exception in read callback: " + boost::current_exception_diagnostic_information()};
	}
}