//
//   This is a single-, double-, triple-, and quadruple-click detector
//   component for LinuxCNC.
//
//   Copyright 2012 Sebastian Kuzminsky <seb@highlab.com>
//
//   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 2 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, write to the Free Software
//   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//

component multiclick "Single-, double-, triple-, and quadruple-click detector";
license "GPL";

pin in  bit in "The input line, this is where we look for clicks.";

pin out bit single_click
"Goes high briefly when a single-click is detected on the 'in' pin.";

pin out bit single_click_only
"""Goes high briefly when a single-click is detected on the 'in' pin
and no second click followed it.""";

pin out bit double_click
"Goes high briefly when a double-click is detected on the 'in' pin.";

pin out bit double_click_only
"""Goes high briefly when a double-click is detected on the 'in' pin
and no third click followed it.""";

pin out bit triple_click
"Goes high briefly when a triple-click is detected on the 'in' pin.";

pin out bit triple_click_only
"""Goes high briefly when a triple-click is detected on the 'in' pin
and no fourth click followed it.""";

pin out bit quadruple_click
"Goes high briefly when a quadruple-click is detected on the 'in' pin.";

pin out bit quadruple_click_only
"""Goes high briefly when a quadruple-click is detected on the 'in'
pin and no fifth click followed it.""";


// for debugging
pin out s32 state;


param rw bit invert_input = FALSE
"""If FALSE (the default), clicks start with rising edges.  If TRUE,
clicks start with falling edges.""";

param rw u32 max_hold_ns  = 250000000
"""If the input is held down longer than this, it's not part of a
multi-click.  (Default 250,000,000 ns, 250 ms.)""";

param rw u32 max_space_ns = 250000000
"""If the input is released longer than this, it's not part of a
multi-click.  (Default 250,000,000 ns, 250 ms.)""";

param rw u32 output_hold_ns = 100000000
"""Positive pulses on the output pins last this long.  (Default
100,000,000 ns, 100 ms.)""";


variable int click_state = 0;  // wish i could have an enum type here


//
// When entering a new non-IDLE state in the state machine, timer is set to
// 0 and timeout is set to the timeout for the new state.
//
// Each time the component's function runs and the state machine is not
// IDLE, the timer is incremented by the thread period.  When the timer
// exceeds the timeout, the state machine resets.
//

variable unsigned timer;
variable unsigned timeout;


//
// When an "X"-click (for X={single,double,triple,quadruple}) is detected,
// the X-click pin goes high and the X_click_hold_timer is set to the
// output_hold_ns param.  Each invocation of the function, the
// X_click_hold_timer is decremented by the thread period, and when the
// timer falls below 0, the X-click output pin goes  back to low again.
//
// Similarly for the X_click_only_hold_timer, but it doesnt start until
// max_space_ns after the click is detected (to ensure that this is not an
// X+1 click).
//

variable unsigned single_click_hold_timer;
variable unsigned single_click_only_hold_timer;

variable unsigned double_click_hold_timer;
variable unsigned double_click_only_hold_timer;

variable unsigned triple_click_hold_timer;
variable unsigned triple_click_only_hold_timer;

variable unsigned quadruple_click_hold_timer;
variable unsigned quadruple_click_only_hold_timer;


description """A click is defined as a rising edge on the 'in' pin,
followed by the 'in' pin being True for at most 'max-hold-ns' nanoseconds,
followed by a falling edge.

A double-click is defined as two clicks, separated by at
most 'max-space-ns' nanoseconds with the 'in' pin in the False state.

I bet you can guess the definition of triple- and quadruple-click.

You probably want to run the input signal through a debounce component
before feeding it to the multiclick detector, if the input is at all
noisy.

The '*-click' pins go high as soon as the input detects the correct
number of clicks.

The '*-click-only' pins go high a short while after the click, after
the click separator space timeout has expired to show that no further
click is coming.  This is useful for triggering halui MDI commands.""";


function _ nofp "Detect single-, double-, triple-, and quadruple-clicks";

;;

typedef enum {
    IDLE = 0,
    SAW_FIRST_RISING_EDGE,
    SAW_FIRST_CLICK,
    SAW_SECOND_RISING_EDGE,
    SAW_SECOND_CLICK,
    SAW_THIRD_RISING_EDGE,
    SAW_THIRD_CLICK,
    SAW_FOURTH_RISING_EDGE,
    SAW_FOURTH_CLICK,
    HELD_TOO_LONG
} state_t;

FUNCTION(_) {
    int new_in = in;

    if (1 == invert_input) {
        new_in = !new_in;
    }

    if (click_state != IDLE) {
        timer += period;
    }


    //
    // update the output pins
    //

    if (single_click_hold_timer > 0) {
        if (single_click_hold_timer > period) {
            single_click_hold_timer -= period;
        } else {
            single_click_hold_timer = 0;
            single_click = 0;
        }
    }

    if (single_click_only_hold_timer > 0) {
        if (single_click_only_hold_timer > period) {
            single_click_only_hold_timer -= period;
        } else {
            single_click_only_hold_timer = 0;
            single_click_only = 0;
        }
    }

    if (double_click_hold_timer > 0) {
        if (double_click_hold_timer > period) {
            double_click_hold_timer -= period;
        } else {
            double_click_hold_timer = 0;
            double_click = 0;
        }
    }

    if (double_click_only_hold_timer > 0) {
        if (double_click_only_hold_timer > period) {
            double_click_only_hold_timer -= period;
        } else {
            double_click_only_hold_timer = 0;
            double_click_only = 0;
        }
    }

    if (triple_click_hold_timer > 0) {
        if (triple_click_hold_timer > period) {
            triple_click_hold_timer -= period;
        } else {
            triple_click_hold_timer = 0;
            triple_click = 0;
        }
    }

    if (triple_click_only_hold_timer > 0) {
        if (triple_click_only_hold_timer > period) {
            triple_click_only_hold_timer -= period;
        } else {
            triple_click_only_hold_timer = 0;
            triple_click_only = 0;
        }
    }

    if (quadruple_click_hold_timer > 0) {
        if (quadruple_click_hold_timer > period) {
            quadruple_click_hold_timer -= period;
        } else {
            quadruple_click_hold_timer = 0;
            quadruple_click = 0;
        }
    }

    if (quadruple_click_only_hold_timer > 0) {
        if (quadruple_click_only_hold_timer > period) {
            quadruple_click_only_hold_timer -= period;
        } else {
            quadruple_click_only_hold_timer = 0;
            quadruple_click_only = 0;
        }
    }


    //
    // update state, if needed
    //

    switch (click_state) {
        case IDLE: {
            if (1 == new_in) {
                click_state = SAW_FIRST_RISING_EDGE;
                timer = 0;
                timeout = max_hold_ns;
            }
            break;
        }

        case SAW_FIRST_RISING_EDGE: {
            if (0 == new_in) {
                click_state = SAW_FIRST_CLICK;
                timer = 0;
                timeout = max_space_ns;
                single_click = 1;
                single_click_hold_timer = output_hold_ns;
            }
            break;
        }

        case SAW_FIRST_CLICK: {
            if (1 == new_in) {
                click_state = SAW_SECOND_RISING_EDGE;
                timer = 0;
                timeout = max_hold_ns;
            }
            break;
        }

        case SAW_SECOND_RISING_EDGE: {
            if (0 == new_in) {
                click_state = SAW_SECOND_CLICK;
                timer = 0;
                timeout = max_space_ns;
                double_click = 1;
                double_click_hold_timer = output_hold_ns;
            }
            break;
        }

        case SAW_SECOND_CLICK: {
            if (1 == new_in) {
                click_state = SAW_THIRD_RISING_EDGE;
                timer = 0;
                timeout = max_hold_ns;
            }
            break;
        }

        case SAW_THIRD_RISING_EDGE: {
            if (0 == new_in) {
                click_state = SAW_THIRD_CLICK;
                timer = 0;
                timeout = max_space_ns;
                triple_click = 1;
                triple_click_hold_timer = output_hold_ns;
            }
            break;
        }

        case SAW_THIRD_CLICK: {
            if (1 == new_in) {
                click_state = SAW_FOURTH_RISING_EDGE;
                timer = 0;
                timeout = max_hold_ns;
            }
            break;
        }

        case SAW_FOURTH_RISING_EDGE: {
            if (0 == new_in) {
                // four clicks is the most we look for, and we just saw it,
                // so we're done now
                click_state = SAW_FOURTH_CLICK;
                timer = 0;
                timeout = max_space_ns;
                quadruple_click = 1;
                quadruple_click_hold_timer = output_hold_ns;
            }
            break;
        }

        case SAW_FOURTH_CLICK: {
            if (1 == new_in) {
                click_state = HELD_TOO_LONG;
            }
            break;
        }

        case HELD_TOO_LONG: {
            if (0 == new_in) {
                click_state = IDLE;
            }
            break;
        }

        default: {
            // invalid click_state!
            click_state = IDLE;
        }
    }

    if ((click_state != IDLE) && (click_state != HELD_TOO_LONG) && (timer > timeout)) {
        if (1 == new_in) {
            click_state = HELD_TOO_LONG;
        } else {
            // timeout after some activity on the input line, trigger one
            // of the "only" outputs if appropriate
            switch (click_state) {
                case SAW_FIRST_CLICK: {
                    single_click_only = 1;
                    single_click_only_hold_timer = output_hold_ns;
                    break;
                }
                case SAW_SECOND_CLICK: {
                    double_click_only = 1;
                    double_click_only_hold_timer = output_hold_ns;
                    break;
                }
                case SAW_THIRD_CLICK: {
                    triple_click_only = 1;
                    triple_click_only_hold_timer = output_hold_ns;
                    break;
                }
                case SAW_FOURTH_CLICK: {
                    quadruple_click_only = 1;
                    quadruple_click_only_hold_timer = output_hold_ns;
                    break;
                }
            }
            click_state = IDLE;
        }
    }

    state = click_state;
}