// Copyright (c) .NET Foundation and contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

#include "pal_utils.h"
#include "trace.h"

bool library_exists_in_dir(const pal::string_t& lib_dir, const pal::string_t& lib_name, pal::string_t* p_lib_path)
{
	pal::string_t lib_path = lib_dir;
	append_path(&lib_path, lib_name.c_str());

	if (!pal::file_exists(lib_path))
	{
		return false;
	}
	if (p_lib_path)
	{
		*p_lib_path = lib_path;
	}
	return true;
}

bool coreclr_exists_in_dir(const pal::string_t& candidate)
{
	pal::string_t test(candidate);
	append_path(&test, LIBCORECLR_NAME);
	trace::verbose(_X("Checking if CoreCLR path exists=[%s]"), test.c_str());
	return pal::file_exists(test);
}

bool ends_with(const pal::string_t& value, const pal::string_t& suffix, bool match_case)
{
	auto cmp = match_case ? pal::strcmp : pal::strcasecmp;
	return (value.size() >= suffix.size()) &&
		cmp(value.c_str() + value.size() - suffix.size(), suffix.c_str()) == 0;
}

bool starts_with(const pal::string_t& value, const pal::string_t& prefix, bool match_case)
{
	if (prefix.empty())
	{
		// Cannot start with an empty string.
		return false;
	}
	auto cmp = match_case ? pal::strncmp : pal::strncasecmp;
	return (value.size() >= prefix.size()) &&
		cmp(value.c_str(), prefix.c_str(), prefix.size()) == 0;
}

void append_path(pal::string_t* path1, const pal::char_t* path2)
{
	if (pal::is_path_rooted(path2))
	{
		path1->assign(path2);
	}
	else
	{
		if (path1->empty() || path1->back() != DIR_SEPARATOR)
		{
			path1->push_back(DIR_SEPARATOR);
		}
		path1->append(path2);
	}
}

pal::string_t get_executable(const pal::string_t& filename)
{
	pal::string_t exe_suffix = pal::exe_suffix();
	if (exe_suffix.empty())
	{
		return filename;
	}

	if (ends_with(filename, exe_suffix, false))
	{
		// We need to strip off the old extension
		pal::string_t result(filename);
		result.erase(result.size() - exe_suffix.size());
		return result;
	}

	return filename;
}

pal::string_t strip_file_ext(const pal::string_t& path)
{
	if (path.empty())
	{
		return path;
	}
	size_t sep_pos = path.rfind(_X("/\\"));
	size_t dot_pos = path.rfind(_X('.'));
	if (sep_pos != pal::string_t::npos && sep_pos > dot_pos)
	{
		return path;
	}
	return path.substr(0, dot_pos);
}

pal::string_t get_filename_without_ext(const pal::string_t& path)
{
	if (path.empty())
	{
		return path;
	}

	size_t name_pos = path.find_last_of(_X("/\\"));
	size_t dot_pos = path.rfind(_X('.'));
	size_t start_pos = (name_pos == pal::string_t::npos) ? 0 : (name_pos + 1);
	size_t count = (dot_pos == pal::string_t::npos || dot_pos < start_pos) ? pal::string_t::npos : (dot_pos - start_pos);
	return path.substr(start_pos, count);
}

pal::string_t get_filename(const pal::string_t& path)
{
	if (path.empty())
	{
		return path;
	}

	auto name_pos = path.find_last_of(DIR_SEPARATOR);
	if (name_pos == pal::string_t::npos)
	{
		return path;
	}

	return path.substr(name_pos + 1);
}

pal::string_t get_directory(const pal::string_t& path)
{
	// Find the last dir separator
	auto path_sep = path.find_last_of(DIR_SEPARATOR);
	if (path_sep == pal::string_t::npos)
	{
		return pal::string_t(path);
	}

	return path.substr(0, path_sep);
}

void replace_char(pal::string_t* path, pal::char_t match, pal::char_t repl)
{
	int pos = 0;
	while ((pos = path->find(match, pos)) != pal::string_t::npos)
	{
		(*path)[pos] = repl;
	}
}

const pal::char_t* get_arch()
{
#if defined __X86__ || defined __i386__ || defined i386 || defined _M_IX86 || defined __386__
	return _X("x86");
#elif defined __ia64 || defined _M_IA64 || defined __ia64__ || defined __x86_64__ || defined _M_X64
	return _X("x64");
#elif defined ARM || defined __arm__ || defined _ARM
	return _X("arm");
#elif defined __aarch64__ || defined _M_ARM64 || __ARM_ARCH_ISA_A64 
	return _X("arm64");
#endif
}

pal::string_t get_last_known_arg(
	const std::unordered_map<pal::string_t, std::vector<pal::string_t>>& opts,
	const pal::string_t& opt_key,
	const pal::string_t& de_fault)
{
	if (opts.count(opt_key))
	{
		const auto& val = opts.find(opt_key)->second;
		return val[val.size() - 1];
	}
	return de_fault;
}

bool parse_known_args(
	const int argc,
	const pal::char_t* argv[],
	const std::vector<pal::string_t>& known_opts,
	// Although multimap would provide this functionality the order of kv, values are
	// not preserved in C++ < C++0x
	std::unordered_map<pal::string_t, std::vector<pal::string_t>>* opts,
	int* num_args)
{
	int arg_i = *num_args;
	while (arg_i < argc)
	{
		pal::string_t arg = argv[arg_i];
		pal::string_t arg_lower = pal::to_lower(arg);
		if (std::find(known_opts.begin(), known_opts.end(), arg_lower) == known_opts.end())
		{
			// Unknown argument.
			break;
		}

		// Known argument, so expect one more arg (value) to be present.
		if (arg_i + 1 >= argc)
		{
			return false;
		}

		trace::verbose(_X("Parsed known arg %s = %s"), arg.c_str(), argv[arg_i + 1]);
		(*opts)[arg_lower].push_back(argv[arg_i + 1]);

		// Increment for both the option and its value.
		arg_i += 2;
	}

	*num_args = arg_i;

	return true;
}

// Try to match 0xEF 0xBB 0xBF byte sequence (no endianness here.)
bool skip_utf8_bom(pal::ifstream_t* stream)
{
	if (stream->eof() || !stream->good())
	{
		return false;
	}

	int peeked = stream->peek();
	if (peeked == EOF || ((peeked & 0xFF) != 0xEF))
	{
		return false;
	}

	unsigned char bytes[3];
	stream->read((char*)bytes, 3);
	if ((stream->gcount() < 3) ||
		(bytes[1] != 0xBB) ||
		(bytes[2] != 0xBF))
	{
		// Reset to 0 if returning false.
		stream->seekg(0, stream->beg);
		return false;
	}

	return true;
}
