/*
 * Keyman is copyright (C) SIL International. MIT License.
 *
 * Description: Used for apply core processor actions to
 *              Keyman for Windows engine.
 */
#include "pch.h"

/**
* Adds characters to the queue to be inserted into the application
* @param app           A pointer to the AITIP instance.
* @param outputString  A null-terminated string of characters to insert into the application
*/

static void
processUnicodeChar(AITIP* app, const km_core_usv* outputString) {
  while (*outputString) {
    if (Uni_IsSMP(*outputString)) {
      app->QueueAction(QIT_CHAR, (Uni_UTF32ToSurrogate1(*outputString)));
      app->QueueAction(QIT_CHAR, (Uni_UTF32ToSurrogate2(*outputString)));
    } else {
      app->QueueAction(QIT_CHAR, *outputString);
    }
    outputString++;
  }
}

static void processAlert(AITIP* app) {
  app->QueueAction(QIT_BELL, 0);
}

static void
processBack(
    AITIP* app,
    const unsigned int code_points_to_delete,
    const km_core_usv* delete_context,
    BOOL* emitKeystroke,
    WORD vkey) {
  if (app->IsLegacy()) {
    for (unsigned int i = 0; i < code_points_to_delete; i++) {
      app->QueueAction(QIT_BACK, BK_DEFAULT);
    }
  }
  else {
    // If there is a selection emit the key (backspace)
    // allowing the application handle clearing selected text in the correct manner.
    if (app->IsTextSelected() && (vkey == VK_BACK)) {
      *emitKeystroke = TRUE;
      return;
    }

    km_core_usv const* delete_context_ptr = delete_context;
    while (*delete_context_ptr) {
      delete_context_ptr++;
    }
    delete_context_ptr--;
    for (; delete_context_ptr >= delete_context; delete_context_ptr--) {
      if (Uni_IsSMP(*delete_context_ptr)) {
        app->QueueAction(QIT_BACK, BK_DEFAULT | BK_SURROGATE);
      }
      else {
        app->QueueAction(QIT_BACK, BK_DEFAULT);
      }
    }
  }
}



static void
processPersistOpt(km_core_actions const* actions, LPINTKEYBOARDINFO activeKeyboard
) {
  for (auto option = actions->persist_options; option->key; option++) {
    SendDebugMessageFormat("Saving option to registry for keyboard [%s].", activeKeyboard->Name);
    SaveKeyboardOptionCoretoRegistry(
        activeKeyboard, reinterpret_cast<LPCWSTR>(option->key), reinterpret_cast<LPCWSTR>(option->value));
  }
}

static void processCapsLock(const km_core_caps_state caps_state_change, BOOL isUp, BOOL Updateable, BOOL externalEvent) {
  BOOL isCapsOn            = IsCapsLockOn();

  // This debug message is useful for understanding the sequence of events around caps lock changes
  //SendDebugMessageFormat("ACTION CAPS STATE:%d FIsUp=%d Updateable=%d ExternalEvent=%d CapsState=%d", caps_state_change, isUp, Updateable,
  //    externalEvent, isCapsOn);

  // We only want to process the Caps Lock key event once;
  // it has to be when updateble=1 as TSF does not consistently
  // have updateable=0 events.
  if (!Updateable || caps_state_change == KM_CORE_CAPS_UNCHANGED) {
    return;
  }
  // Turn three state value into a boolean for whether capslock should be on or off,
  // we only want to process the key event if the state is changing.
  BOOL required_caps_state = (caps_state_change == KM_CORE_CAPS_ON);

  if (isCapsOn != required_caps_state) {
    SendDebugMessageFormat(
      "Simulate CapsLock %s: FIsUp=%d CurrentCapsState=%d ExternalEvent=%d",
      required_caps_state ? "ON" : "OFF", isUp, isCapsOn, externalEvent);
    keybd_event(VK_CAPITAL, SCAN_FLAG_KEYMAN_KEY_EVENT, 0, 0);
    keybd_event(VK_CAPITAL, SCAN_FLAG_KEYMAN_KEY_EVENT, KEYEVENTF_KEYUP, 0);
  }
}

BOOL ProcessActions(BOOL* emitKeystroke)
{
  PKEYMAN64THREADDATA _td = ThreadGlobals();
  if (!_td) return FALSE;

  km_core_actions const* core_actions = km_core_state_get_actions(_td->lpActiveKeyboard->lpCoreKeyboardState);

  _td->CoreProcessEventRun = FALSE;

  processBack(_td->app, core_actions->code_points_to_delete, core_actions->deleted_context, emitKeystroke, _td->state.vkey);
  processUnicodeChar(_td->app, core_actions->output);
  if (core_actions->persist_options != NULL) {
    processPersistOpt(core_actions, _td->lpActiveKeyboard);
  }
  if (core_actions->do_alert) {
    processAlert(_td->app);
  }
  if (core_actions->emit_keystroke) {
    *emitKeystroke = TRUE;
  }
  processCapsLock(core_actions->new_caps_lock_state, !_td->state.isDown, _td->TIPFUpdateable, FALSE);

  return TRUE;
}

BOOL
ProcessActionsNonUpdatableParse(BOOL* emitKeystroke) {
  PKEYMAN64THREADDATA _td = ThreadGlobals();
  if (!_td) {
    return FALSE;
  }

  if (_td->TIPFUpdateable) {  // ensure only run when not updateable
    return FALSE;
  }
  _td->CoreProcessEventRun = TRUE;

  km_core_actions const* core_actions = km_core_state_get_actions(_td->lpActiveKeyboard->lpCoreKeyboardState);

  if (core_actions->emit_keystroke) {
    *emitKeystroke = TRUE;
    SendDebugMessageFormat("EMIT_KEYSTROKE");
    _td->CoreProcessEventRun  = FALSE;  // If we emit the key stroke on this parse we don't need the second parse
  }
  return TRUE;
}

BOOL
ProcessActionsExternalEvent() {
  PKEYMAN64THREADDATA _td = ThreadGlobals();
  if (!_td) {
    return FALSE;
  }
  km_core_actions const* core_actions = km_core_state_get_actions(_td->lpActiveKeyboard->lpCoreKeyboardState);
  processCapsLock(core_actions->new_caps_lock_state, !_td->state.isDown, TRUE, TRUE);
  return TRUE;
}