// -*- mode: C; tab-width: 4 ; indent-tabs-mode: nil -*-
//
//  Unfified Keyboard Project
//  ASDF keyboard firmware
//
//  asdf_modifiers.h
//
// Copyright 2019 David Fenyes
//
// This program is free software: you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free Software
// Foundation, either version 3 of the License, or (at your option) any later
// version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
// details.
//
// You should have received a copy of the GNU General Public License along with
// this program. If not, see <https://www.gnu.org/licenses/>.

#if !defined(ASDF_MODIFIERS_H)
#define ASDF_MODIFIERS_H

// The active modifiers are used to build an index into a map that determinds
// which modifier map is selected.  The following define the bit position for each modifier.
// For example, if SHIFT and CTRL are active, the modifier index would be
//
// (1 << ASDF_MODIFIERS_SHIFT_POS) | (1 << ASDF_MODIFIERS_CAPS_POS)
// = (1 << 0) | (1 << 1)
// = (1 | 2)
// = 3
//
// So, if CTRL+SHIFT is a special modifier, then modifier_mapping[3] will point
// to the CTRL+SHIFT map. Alternatively, if CTRL+SHIFT is the same as just CTRL,
// then modifier_mapping[3] will point to the CTRL map.
#define ASDF_MODIFIERS_SHIFT_POS 0
#define ASDF_MODIFIERS_CAPS_POS 1
#define ASDF_MODIFIERS_CTRL_POS 2

#define ASDF_MODIFIERS_SHIFT_MASK (1 << ASDF_MODIFIERS_SHIFT_POS)
#define ASDF_MODIFIERS_CAPS_MASK (1 << ASDF_MODIFIERS_CAPS_POS)
#define ASDF_MODIFIERS_CTRL_MASK (1 << ASDF_MODIFIERS_CTRL_POS)

// Define the legal SHIFT and SHIFTLOCK states
typedef enum {
  SHIFT_OFF_ST = 0,
  SHIFT_ON_ST = 1,
  SHIFT_LOCKED_ST = 2,
  SHIFT_BOTH_ST = 3 // Never explicitly set. SHIFT and SHIFTLOCK together.

} shift_state_t;

// Define the legal CAPS and CAPSLOCK states
typedef enum {
  CAPS_OFF_ST = 0,
  CAPS_LOCKED_ST = 1,
} caps_state_t;

// Define the legal CTRL states
typedef enum { CTRL_OFF_ST = 0, CTRL_ON_ST = 1 } ctrl_state_t;

// Define the legal modifier mappings. In this case, we define 4 maps, for PLAIN
// (no modifier), SHIFT, CAPS, and CTRL. When combinations of these modifiers
// are active, then the precedence is determined by the modifier_mapping[]
// array.
typedef enum {
  MOD_PLAIN_MAP = 0,
  MOD_SHIFT_MAP,
  MOD_CAPS_MAP,
  MOD_CTRL_MAP,
  ASDF_MOD_NUM_MODIFIERS
} modifier_index_t;

// PROCEDURE: asdf_modifier_shift_activate
// INPUTS: none
// OUTPUTS: none
// DESCRIPTION: sets SHIFT state to ON
//
void asdf_modifier_shift_activate(void);

// PROCEDURE: asdf_modifier_shiftlock_on_activate
// INPUTS: none
// OUTPUTS: none
// DESCRIPTION: sets SHIFTLOCK state to ON
void asdf_modifier_shiftlock_on_activate(void);

// PROCEDURE: asdf_modifier_shiftlock_toggle_activate
// INPUTS: none
// OUTPUTS: none
// DESCRIPTION: Toggles SHIFTLOCK state.
void asdf_modifier_shiftlock_toggle_activate(void);

// PROCEDURE: asdf_modifier_capslock_activate
// INPUTS: none
// OUTPUTS: none
// DESCRIPTION: Turns on Capslock state
//
void asdf_modifier_capslock_activate(void);

// PROCEDURE: asdf_modifier_ctrl_activate
// INPUTS: none
// OUTPUTS: none
// DESCRIPTION: Turns on CTRL mode
//
void asdf_modifier_ctrl_activate(void);

// PROCEDURE: asdf_modifier_shift_deactivate
// INPUTS: none
// OUTPUTS: none
// DESCRIPTION: Turns off shift mode.
//
void asdf_modifier_shift_deactivate(void);

// PROCEDURE: asdf_modifier_ctrl_deactivate
// INPUTS: none
// OUTPUTS: none
// DESCRIPTION: Turns off CTRL mode
//
void asdf_modifier_ctrl_deactivate(void);

// PROCEDURE: asdf_modifiers_init
// INPUTS: none
// OUTPUTS: none
// DESCRIPTION: Initialize the modifier key state variables to OFF state
//
void asdf_modifiers_init(void);

// PROCEDURE: asdf_modifier_index
// INPUTS: none
// OUTPUTS: returns uint8_t index into key map, based on modifier key status
// DESCRIPTION: See OUTPUTS
//
modifier_index_t asdf_modifier_index(void);

#endif // !defined (ASDF_MODIFIERS_H)

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