// This file is distributed under the BSD License.
// See "license.txt" for details.
// Copyright 2009-2012, Jonathan Turner (jonathan@emptycrate.com)
// Copyright 2009-2018, Jason Turner (jason@emptycrate.com)
// http://www.chaiscript.com

// This is an open source non-commercial project. Dear PVS-Studio, please check it.
// PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com

#include <iostream>
#include <list>
#include <regex>

#ifdef _MSC_VER
#define _CRT_SECURE_NO_WARNINGS
#endif

#include "../static_libs/chaiscript_parser.hpp"
#include "../static_libs/chaiscript_stdlib.hpp"
#include <chaiscript/chaiscript_basic.hpp>

#ifdef READLINE_AVAILABLE
#include <readline/history.h>
#include <readline/readline.h>
#else

char *mystrdup(const char *s) {
 size_t len = strlen(s); // Space for length plus nul
 char *d = static_cast<char *>(malloc(len + 1));
 if (d == nullptr) {
 return nullptr;
 } // No memory
#ifdef CHAISCRIPT_MSVC
 strcpy_s(d, len + 1, s); // Copy the characters
#else
 strncpy(d, s, len); // Copy the characters
#endif
 d[len] = '0円';
 return d; // Return the new string
}

char *readline(const char *p) {
 std::string retval;
 std::cout << p;
 std::getline(std::cin, retval);
 return std::cin.eof() ? nullptr : mystrdup(retval.c_str());
}

void add_history(const char * /*unused*/) {}
void using_history() {}
#endif

void *cast_module_symbol(std::vector<std::string> (*t_path)()) {
 union cast_union {
 std::vector<std::string> (*in_ptr)();
 void *out_ptr;
 };

 cast_union c;
 c.in_ptr = t_path;
 return c.out_ptr;
}

std::vector<std::string> default_search_paths() {
 std::vector<std::string> paths;

#ifndef CHAISCRIPT_NO_DYNLOAD
#ifdef CHAISCRIPT_WINDOWS // force no unicode
 CHAR path[4096];
 int size = GetModuleFileNameA(nullptr, path, sizeof(path) - 1);

 std::string exepath(path, size);

 size_t lastslash = exepath.rfind('\\');
 size_t secondtolastslash = exepath.rfind('\\', lastslash - 1);
 if (lastslash != std::string::npos) {
 paths.push_back(exepath.substr(0, lastslash));
 }

 if (secondtolastslash != std::string::npos) {
 return {exepath.substr(0, secondtolastslash) + "\\lib\\chaiscript\\"};
 }
#else

 std::string exepath;

 std::vector<char> buf(2048);
 ssize_t size = -1;

 if ((size = readlink("/proc/self/exe", &buf.front(), buf.size())) >= 0) {
 exepath = std::string(&buf.front(), static_cast<size_t>(size));
 }

 if (exepath.empty()) {
 if ((size = readlink("/proc/curproc/file", &buf.front(), buf.size())) >= 0) {
 exepath = std::string(&buf.front(), static_cast<size_t>(size));
 }
 }

 if (exepath.empty()) {
 if ((size = readlink("/proc/self/path/a.out", &buf.front(), buf.size())) >= 0) {
 exepath = std::string(&buf.front(), static_cast<size_t>(size));
 }
 }

 if (exepath.empty()) {
 Dl_info rInfo;
 memset(&rInfo, 0, sizeof(rInfo));
 if (dladdr(cast_module_symbol(&default_search_paths), &rInfo) == 0 || rInfo.dli_fname == nullptr) {
 return paths;
 }

 exepath = std::string(rInfo.dli_fname);
 }

 size_t lastslash = exepath.rfind('/');

 size_t secondtolastslash = exepath.rfind('/', lastslash - 1);
 if (lastslash != std::string::npos) {
 paths.push_back(exepath.substr(0, lastslash + 1));
 }

 if (secondtolastslash != std::string::npos) {
 paths.push_back(exepath.substr(0, secondtolastslash) + "/lib/chaiscript/");
 }
#endif
#endif // ifndef CHAISCRIPT_NO_DYNLOAD

 return paths;
}

void help(int n) {
 if (n >= 0) {
 std::cout << "ChaiScript evaluator. To evaluate an expression, type it and press <enter>.\n";
 std::cout << "Additionally, you can inspect the runtime system using:\n";
 std::cout << " dump_system() - outputs all functions registered to the system\n";
 std::cout << " dump_object(x) - dumps information about the given symbol\n";
 } else {
 std::cout << "usage : chai [option]+\n";
 std::cout << "option:" << '\n';
 std::cout << " -h | --help" << '\n';
 std::cout << " -i | --interactive" << '\n';
 std::cout << " -c | --command cmd" << '\n';
 std::cout << " -v | --version" << '\n';
 std::cout << " - --stdin" << '\n';
 std::cout << " filepath" << '\n';
 }
}

std::string throws_exception(const std::function<void()> &f) {
 try {
 f();
 } catch (const std::exception &e) {
 return e.what();
 }

 return "";
}

chaiscript::exception::eval_error get_eval_error(const std::function<void()> &f) {
 try {
 f();
 } catch (const chaiscript::exception::eval_error &e) {
 return e;
 }

 throw std::runtime_error("no exception throw");
}

std::string get_next_command() {
 std::string retval("quit");
 if (!std::cin.eof()) {
 char *input_raw = readline("eval> ");
 if (input_raw != nullptr) {
 add_history(input_raw);

 std::string val(input_raw);
 size_t pos = val.find_first_not_of("\t\n");
 if (pos != std::string::npos) {
 val.erase(0, pos);
 }
 pos = val.find_last_not_of("\t\n");
 if (pos != std::string::npos) {
 val.erase(pos + 1, std::string::npos);
 }

 retval = val;

 ::free(input_raw);
 }
 }
 if (retval == "quit" || retval == "exit" || retval == "help" || retval == "version") {
 retval += "(0)";
 }
 return retval;
}

// We have to wrap exit with our own because Clang has a hard time with
// function pointers to functions with special attributes (system exit being marked NORETURN)
void myexit(int return_val) {
 exit(return_val);
}

void interactive(chaiscript::ChaiScript_Basic &chai) {
 using_history();

 for (;;) {
 std::string input = get_next_command();
 try {
 // evaluate input
 chaiscript::Boxed_Value val = chai.eval(input);

 // Then, we try to print the result of the evaluation to the user
 if (!val.get_type_info().bare_equal(chaiscript::user_type<void>())) {
 try {
 std::cout << chai.eval<std::function<std::string(const chaiscript::Boxed_Value &bv)>>("to_string")(val) << '\n';
 } catch (...) {
 } // If we can't, do nothing
 }
 } catch (const chaiscript::exception::eval_error &ee) {
 std::cout << ee.what();
 if (!ee.call_stack.empty()) {
 std::cout << "during evaluation at (" << ee.call_stack[0].start().line << ", " << ee.call_stack[0].start().column << ")";
 }
 std::cout << '\n';
 } catch (const std::exception &e) {
 std::cout << e.what();
 std::cout << '\n';
 }
 }
}

double now() {
 using namespace std::chrono;
 auto now = high_resolution_clock::now();
 return duration_cast<duration<double>>(now.time_since_epoch()).count();
}

int main(int argc, char *argv[]) {
// Disable deprecation warning for getenv call.
#ifdef CHAISCRIPT_MSVC
#pragma warning(push)
#pragma warning(disable : 4996)
#endif

 const char *usepath = getenv("CHAI_USE_PATH");
 const char *modulepath = getenv("CHAI_MODULE_PATH");

#ifdef CHAISCRIPT_MSVC
#pragma warning(pop)
#endif

 std::vector<std::string> usepaths;
 usepaths.emplace_back("");
 if (usepath != nullptr) {
 usepaths.emplace_back(usepath);
 }

 std::vector<std::string> modulepaths;
 std::vector<std::string> searchpaths = default_search_paths();
 modulepaths.insert(modulepaths.end(), searchpaths.begin(), searchpaths.end());
 modulepaths.emplace_back("");
 if (modulepath != nullptr) {
 modulepaths.emplace_back(modulepath);
 }

 chaiscript::ChaiScript_Basic chai(create_chaiscript_stdlib(), create_chaiscript_parser(), modulepaths, usepaths);

 chai.add(chaiscript::fun(&myexit), "exit");
 chai.add(chaiscript::fun(&myexit), "quit");
 chai.add(chaiscript::fun(&help), "help");
 chai.add(chaiscript::fun(&throws_exception), "throws_exception");
 chai.add(chaiscript::fun(&get_eval_error), "get_eval_error");
 chai.add(chaiscript::fun(&now), "now");

 bool eval_error_ok = false;
 bool boxed_exception_ok = false;
 bool any_exception_ok = false;

 for (int i = 0; i < argc; ++i) {
 if (i == 0 && argc > 1) {
 ++i;
 }

 std::string arg(i != 0 ? argv[i] : "--interactive");

 enum {
 eInteractive,
 eCommand,
 eFile
 } mode
 = eCommand;

 if (arg == "-c" || arg == "--command") {
 if ((i + 1) >= argc) {
 std::cout << "insufficient input following " << arg << '\n';
 return EXIT_FAILURE;
 }
 arg = argv[++i];

 } else if (arg == "-" || arg == "--stdin") {
 arg = "";
 std::string line;
 while (std::getline(std::cin, line)) {
 arg += line + '\n';
 }
 } else if (arg == "-v" || arg == "--version") {
 arg = "print(version())";
 } else if (arg == "-h" || arg == "--help") {
 arg = "help(-1)";
 } else if (arg == "-e" || arg == "--evalerrorok") {
 eval_error_ok = true;
 continue;
 } else if (arg == "--exception") {
 boxed_exception_ok = true;
 continue;
 } else if (arg == "--any-exception") {
 any_exception_ok = true;
 continue;
 } else if (arg == "-i" || arg == "--interactive") {
 mode = eInteractive;
 } else if (arg.find('-') == 0) {
 std::cout << "unrecognised argument " << arg << '\n';
 return EXIT_FAILURE;
 } else {
 mode = eFile;
 }

 try {
 switch (mode) {
 case eInteractive:
 interactive(chai);
 break;
 case eCommand:
 chai.eval(arg);
 break;
 case eFile:
 chai.eval_file(arg);
 }
 } catch (const chaiscript::exception::eval_error &ee) {
 std::cout << ee.pretty_print();
 std::cout << '\n';

 if (!eval_error_ok) {
 return EXIT_FAILURE;
 }
 } catch (const chaiscript::Boxed_Value &e) {
 std::cout << "Unhandled exception thrown of type " << e.get_type_info().name() << '\n';

 if (!boxed_exception_ok) {
 return EXIT_FAILURE;
 }
 } catch (const chaiscript::exception::load_module_error &e) {
 std::cout << "Unhandled module load error\n"
 << e.what() << '\n';
 } catch (std::exception &e) {
 std::cout << "Unhandled standard exception: " << e.what() << '\n';
 if (!any_exception_ok) {
 throw;
 }
 } catch (...) {
 std::cout << "Unhandled unknown exception" << '\n';
 if (!any_exception_ok) {
 throw;
 }
 }
 }

 return EXIT_SUCCESS;
}