/*
  Copyright:    © 2018 SIL International.
  Description:  This is a test implementation of the keyboard processor API to
                enable testing API clients against a basic keyboard and give
                them something to link against and load.
                TODO: Add a mecahnism to trigger output of PERSIST_OPT &
                RESET_OPT actions items, options support and context matching.
  Create Date:  17 Oct 2018
  Authors:      Tim Eves (TSE)
  History:      17 Oct 2018 - TSE - Initial implementation.
*/

#include "mock/mock_processor.hpp"
#include "state.hpp"

namespace
{

  // An table of VKEY to character sequence mappings, one per shift state.
  // An empty string inidicates no mapping.
  constexpr char const table[2][256][4] = {
    {
      /*00-0F*/"","","","","","","","","","\t","","","","\015","","",
      /*10-1F*/"","","","","","","","","","","","\033","","","","",
      /*20-2F*/" ","","","","","","","","","","","","","","","",
      /*30-3F*/"0","1","2","3","4","5","6","7","8","9","","","","","","",
      /*40-4F*/"","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o",
      /*50-5F*/"p","q","r","s","t","u","v","w","x","y","z","","","","","",
      /*60-6F*/"0","1","2","3","4","5","6","7","8","9","*","+","","-",".","/",
      /*70-7F*/"f1","f2","f3","f4","f5","f6","f7","f8","f9","f10","f11","f12","f13","f14","f15","f16",
      /*80-8F*/"f17","f18","f19","f20","f24","","","","","","","","","","","",
      /*90-9F*/"","","","","","","","","","","","","","","","",
      /*A0-AF*/"","","","","","","","","","","","","","","","",
      /*B0-BF*/"","","","","","","","","","",";","=",",","-",".","/",
      /*C0-CF*/"`","","","","","","","","","","","","","","","",
      /*D0-DF*/"","","","","","","","","","","","[","\\","]","'","",
      /*E0-EF*/"","","","","","","","","","","","","","","","",
      /*F0-FF*/"","","","","","","","","","","","","","","","",
    },
    {
      /*00-0F*/"","","","","","","","","","\t","","","","\015","","",
      /*10-1F*/"","","","","","","","","","","","\033","","","","",
      /*20-2F*/" ","","","","","","","","","","","","","","","",
      /*30-3F*/")","!","@","#","$","%","^","&","*","(","","","","","","",
      /*40-4F*/"","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O",
      /*50-5F*/"P","Q","R","S","T","U","V","W","X","Y","Z","","","","","",
      /*60-6F*/"","","","","","","","","","","","","","","","",
      /*70-7F*/"","","","","","","","","","","","","","","","",
      /*80-8F*/"","","","","","","","","","","","","","","","",
      /*90-9F*/"","","","","","","","","","","","","","","","",
      /*A0-AF*/"","","","","","","","","","","","","","","","",
      /*B0-BF*/"","","","","","","","","","",":","+","<","_",">","?",
      /*C0-CF*/"~","","","","","","","","","","","","","","","",
      /*D0-DF*/"","","","","","","","","","","","{","|","}","\"","",
      /*E0-EF*/"","","","","","","","","","","","","","","","",
      /*F0-FF*/"","","","","","","","","","","","","","","","",
    }
  };


  constexpr km_kbp_attr const engine_attrs = {
    256,
    KM_KBP_LIB_CURRENT,
    KM_KBP_LIB_AGE,
    KM_KBP_LIB_REVISION,
    KM_KBP_TECH_MOCK,
    "SIL International"
  };

}

namespace km {
  namespace kbp
  {
    mock_processor::mock_processor(kbp::path const & path)
    : abstract_processor(
        keyboard_attributes(path.stem(), u"3.145", path.parent(), {
          option{KM_KBP_OPT_KEYBOARD, u"__test_point", u"F2 pressed test save."},
          option{KM_KBP_OPT_KEYBOARD, u"hello", u"-"}
      }))
    {
    }


    km_kbp_status mock_processor::process_event(km_kbp_state *state, km_kbp_virtual_key vk, uint16_t modifier_state)
    {
      assert(state);
      if (!state)
        return KM_KBP_STATUS_INVALID_ARGUMENT;

      try
      {
        // At the start of every process_event allways clear the action_items
        state->actions().clear();

        switch (vk)
        {
        case KM_KBP_VKEY_BKSP:
          state->context().pop_back();
          state->actions().push_backspace();
          break;

        default:
        {
          auto shift_state = bool(modifier_state & KM_KBP_MODIFIER_SHIFT);
          // Only process further one of the shift states has something to output.
          if (table[0][vk][0] || table[1][vk][0])
          {
            auto char_seq = table[shift_state][vk];

            for (auto c = char_seq; *c; ++c)
            {
              km_kbp_usv usv = *c;
              state->context().push_character(usv);
              state->actions().push_character(usv);
            }
            state->actions().commit();

            return KM_KBP_STATUS_OK;
          }

          // Both shift states output nothing, generate an alert.
          state->actions().push_alert();
          break;
        }
        }

        state->actions().commit();
      }
      catch (std::bad_alloc)
      {
        state->actions().clear();
        return KM_KBP_STATUS_NO_MEM;
      }

      return KM_KBP_STATUS_OK;

    }

    void mock_processor::update_option(km_kbp_state *,
                                       km_kbp_option_scope,
                                       std::u16string const &,
                                       std::u16string const &)
    {};

    void mock_processor::init_state(std::vector<option> &default_env) {
      default_env.emplace_back(KM_KBP_OPT_ENVIRONMENT, u"hello", u"-");
      default_env.emplace_back();
    };

    km_kbp_attr const & mock_processor::attributes() const {
      return engine_attrs;
    }

    km_kbp_status mock_processor::validate() const { return KM_KBP_STATUS_OK; }

    km_kbp_status null_processor::validate() const { return KM_KBP_STATUS_INVALID_ARGUMENT; }
  } // namespace kbp
} // namespace km