/*
* (C) 2015,2017 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include "cli.h"
#include "argparse.h"
#include <botan/rng.h>
#include <botan/internal/os_utils.h>
#include <fstream>
#include <iostream>

#if defined(BOTAN_HAS_HEX_CODEC)
   #include <botan/hex.h>
#endif

#if defined(BOTAN_HAS_BASE64_CODEC)
   #include <botan/base64.h>
#endif

#if defined(BOTAN_HAS_BASE58_CODEC)
   #include <botan/base58.h>
#endif

namespace Botan_CLI {

Command::Command(const std::string& cmd_spec) : m_spec(cmd_spec) {
   // for checking all spec strings at load time
   //m_args.reset(new Argument_Parser(m_spec));
}

Command::~Command() = default;

std::string Command::cmd_name() const {
   return m_spec.substr(0, m_spec.find(' '));
}

std::string Command::help_text() const {
   return "Usage: " + m_spec;
}

//static
std::vector<std::string> Command::split_on(const std::string& str, char delim) {
   return Argument_Parser::split_on(str, delim);
}

int Command::run(const std::vector<std::string>& params) {
   try {
      const std::vector<std::string> extra_flags = {"verbose", "help"};
      const std::vector<std::string> extra_opts = {"output", "error-output", "rng-type", "drbg-seed"};

      m_args = std::make_unique<Argument_Parser>(m_spec, extra_flags, extra_opts);

      m_args->parse_args(params);

      if(m_args->has_arg("output")) {
         const std::string output_file = get_arg("output");

         if(!output_file.empty()) {
            m_output_stream = std::make_unique<std::ofstream>(output_file, std::ios::binary);
            if(!m_output_stream->good()) {
               throw CLI_IO_Error("opening", output_file);
            }
         }
      }

      if(m_args->has_arg("error-output")) {
         const std::string output_file = get_arg("error-output");

         if(!output_file.empty()) {
            m_error_output_stream = std::make_unique<std::ofstream>(output_file, std::ios::binary);
            if(!m_error_output_stream->good()) {
               throw CLI_IO_Error("opening", output_file);
            }
         }
      }

      if(flag_set("help")) {
         output() << help_text() << "\n";
         return 2;
      }

      this->go();
      return m_return_code;
   } catch(CLI_Usage_Error& e) {
      error_output() << "Usage error: " << e.what() << "\n";
      error_output() << help_text() << "\n";
      return 1;
   } catch(std::exception& e) {
      error_output() << "Error: " << e.what() << "\n";
      return 2;
   } catch(...) {
      error_output() << "Error: unknown exception\n";
      return 2;
   }
}

bool Command::flag_set(const std::string& flag_name) const {
   return m_args->flag_set(flag_name);
}

std::string Command::get_arg(const std::string& opt_name) const {
   return m_args->get_arg(opt_name);
}

/*
* Like get_arg() but if the argument was not specified or is empty, returns otherwise
*/
std::string Command::get_arg_or(const std::string& opt_name, const std::string& otherwise) const {
   return m_args->get_arg_or(opt_name, otherwise);
}

std::optional<std::string> Command::get_arg_maybe(const std::string& opt_name) const {
   auto arg = m_args->get_arg(opt_name);
   if(arg.empty()) {
      return std::nullopt;
   } else {
      return arg;
   }
}

size_t Command::get_arg_sz(const std::string& opt_name) const {
   return m_args->get_arg_sz(opt_name);
}

uint16_t Command::get_arg_u16(const std::string& opt_name) const {
   const size_t val = get_arg_sz(opt_name);
   if(static_cast<uint16_t>(val) != val) {
      throw CLI_Usage_Error("Argument " + opt_name + " has value out of allowed range");
   }
   return static_cast<uint16_t>(val);
}

uint32_t Command::get_arg_u32(const std::string& opt_name) const {
   const size_t val = get_arg_sz(opt_name);
   if(static_cast<uint32_t>(val) != val) {
      throw CLI_Usage_Error("Argument " + opt_name + " has value out of allowed range");
   }
   return static_cast<uint32_t>(val);
}

std::vector<std::string> Command::get_arg_list(const std::string& what) const {
   return m_args->get_arg_list(what);
}

std::ostream& Command::output() {
   if(m_output_stream) {
      return *m_output_stream;
   }
   return std::cout;
}

std::ostream& Command::error_output() {
   if(m_error_output_stream) {
      return *m_error_output_stream;
   }
   return std::cerr;
}

std::vector<uint8_t> Command::slurp_file(const std::string& input_file, size_t buf_size) const {
   std::vector<uint8_t> buf;
   auto insert_fn = [&](const uint8_t b[], size_t l) { buf.insert(buf.end(), b, b + l); };
   Command::read_file(input_file, insert_fn, buf_size);
   return buf;
}

std::string Command::slurp_file_as_str(const std::string& input_file, size_t buf_size) const {
   std::string str;
   auto insert_fn = [&](const uint8_t b[], size_t l) { str.append(reinterpret_cast<const char*>(b), l); };
   Command::read_file(input_file, insert_fn, buf_size);
   return str;
}

void Command::read_file(const std::string& input_file,
                        const std::function<void(uint8_t[], size_t)>& consumer_fn,
                        size_t buf_size) {
   if(input_file == "-") {
      do_read_file(std::cin, consumer_fn, buf_size);
   } else {
      std::ifstream in(input_file, std::ios::binary);
      if(!in) {
         throw CLI_IO_Error("reading file", input_file);
      }
      do_read_file(in, consumer_fn, buf_size);
   }
}

//static
void Command::do_read_file(std::istream& in,
                           const std::function<void(uint8_t[], size_t)>& consumer_fn,
                           size_t buf_size) {
   // Avoid an infinite loop on --buf-size=0
   std::vector<uint8_t> buf(buf_size == 0 ? 4096 : buf_size);

   while(in.good()) {
      in.read(reinterpret_cast<char*>(buf.data()), buf.size());
      const size_t got = static_cast<size_t>(in.gcount());
      consumer_fn(buf.data(), got);
   }
}

Botan::RandomNumberGenerator& Command::rng() {
   return *rng_as_shared();
}

std::shared_ptr<Botan::RandomNumberGenerator> Command::rng_as_shared() {
   if(m_rng == nullptr) {
      m_rng = cli_make_rng(get_arg("rng-type"), get_arg("drbg-seed"));
   }

   return m_rng;
}

std::string Command::get_passphrase_arg(const std::string& prompt, const std::string& opt_name) {
   std::string s = get_arg(opt_name);
   if(s != "-") {
      return s;
   }
   return get_passphrase(prompt);
}

namespace {

bool echo_suppression_supported() {
   auto echo = Botan::OS::suppress_echo_on_terminal();
   return (echo != nullptr);
}

}  // namespace

std::string Command::get_passphrase(const std::string& prompt) {
   if(echo_suppression_supported() == false) {
      error_output() << "Warning: terminal echo suppression not enabled for this platform\n";
   }

   error_output() << prompt << ": " << std::flush;
   std::string pass;

   auto echo_suppress = Botan::OS::suppress_echo_on_terminal();

   std::getline(std::cin, pass);

   return pass;
}

//static
std::string Command::format_blob(const std::string& format, const uint8_t bits[], size_t len) {
#if defined(BOTAN_HAS_HEX_CODEC)
   if(format == "hex") {
      return Botan::hex_encode(bits, len);
   }
#endif

#if defined(BOTAN_HAS_BASE64_CODEC)
   if(format == "base64") {
      return Botan::base64_encode(bits, len);
   }
#endif

#if defined(BOTAN_HAS_BASE58_CODEC)
   if(format == "base58") {
      return Botan::base58_encode(bits, len);
   }
   if(format == "base58check") {
      return Botan::base58_check_encode(bits, len);
   }
#endif

   // If we supported format, we would have already returned
   throw CLI_Usage_Error("Unknown or unsupported format type");
}

// Registration code

Command::Registration::Registration(const std::string& name, const Command::cmd_maker_fn& maker_fn) {
   std::map<std::string, Command::cmd_maker_fn>& reg = Command::global_registry();

   if(reg.contains(name)) {
      throw CLI_Error("Duplicated registration of command " + name);
   }

   reg.insert(std::make_pair(name, maker_fn));
}

//static
std::map<std::string, Command::cmd_maker_fn>& Command::global_registry() {
   static std::map<std::string, Command::cmd_maker_fn> g_cmds;
   return g_cmds;
}

//static
std::vector<std::string> Command::registered_cmds() {
   std::vector<std::string> cmds;
   for(auto& cmd : Command::global_registry()) {
      cmds.push_back(cmd.first);
   }
   return cmds;
}

//static
std::unique_ptr<Command> Command::get_cmd(const std::string& name) {
   const auto& reg = Command::global_registry();

   auto i = reg.find(name);
   if(i != reg.end()) {
      return i->second();
   }

   return nullptr;
}

}  // namespace Botan_CLI
