Implement axis targets, axis -> button and axis -> relative axis mappings. (#1)

Co-authored-by: Anna Rose Wiggins <annabunches@gmail.com>
Co-committed-by: Anna Rose Wiggins <annabunches@gmail.com>

internal/mappingrules/mapping_rule_axis_to_button.go

@@ -4,48 +4,106 @@ import (
 	"time"
 
 	"github.com/holoplot/go-evdev"
+	"github.com/jonboulle/clockwork"
 )
 
-// TODO: This whole file is still WIP
+// MappingRuleAxisToButton represents a rule that converts an axis input into a (potentially repeating)
+// button output.
 type MappingRuleAxisToButton struct {
 	MappingRuleBase
-	Input          *RuleTargetAxis
-	Output         *RuleTargetButton
-	RepeatSpeedMin int32
-	RepeatSpeedMax int32
-	lastValue      int32
-	lastEvent      time.Time
+	Input         *RuleTargetAxis
+	Output        *RuleTargetButton
+	RepeatRateMin int
+	RepeatRateMax int
+	nextEvent     time.Duration
+	lastEvent     time.Time
+	repeat        bool
+	pressed       bool // "pressed" indicates that we've sent the output button signal, but still need to send the button release
+	active        bool // "active" is true whenever the input is not in a deadzone
+	clock         clockwork.Clock
 }
 
-func (rule *MappingRuleAxisToButton) MatchEvent(device *evdev.InputDevice, event *evdev.InputEvent, mode *string) (*evdev.InputDevice, *evdev.InputEvent) {
+func NewMappingRuleAxisToButton(base MappingRuleBase, input *RuleTargetAxis, output *RuleTargetButton, repeatRateMin, repeatRateMax int) *MappingRuleAxisToButton {
+	return &MappingRuleAxisToButton{
+		MappingRuleBase: base,
+		Input:           input,
+		Output:          output,
+		RepeatRateMin:   repeatRateMin,
+		RepeatRateMax:   repeatRateMax,
+		lastEvent:       time.Now(),
+		nextEvent:       NoNextEvent,
+		repeat:          repeatRateMin != 0 && repeatRateMax != 0,
+		pressed:         false,
+		active:          false,
+		clock:           clockwork.NewRealClock(),
+	}
+}
+
+func (rule *MappingRuleAxisToButton) MatchEvent(device RuleTargetDevice, event *evdev.InputEvent, mode *string) (*evdev.InputDevice, *evdev.InputEvent) {
+
 	if !rule.MappingRuleBase.modeCheck(mode) ||
-		!rule.Input.MatchEvent(device, event) {
+		!rule.Input.MatchEventDeviceAndCode(device, event) {
 		return nil, nil
 	}
 
-	// set the last value to the normalized input value
-	rule.lastValue = rule.Input.NormalizeValue(event.Value)
+	// If we're inside the deadzone, unset the next event
+	if rule.Input.InDeadZone(event.Value) {
+		rule.nextEvent = NoNextEvent
+		rule.active = false
+		return nil, nil
+	}
+
+	// If we aren't repeating, we trigger the event immediately
+	// We also only set this if active == false, so that only one
+	// event can be emitted per "active" period
+	if !rule.repeat && !rule.active {
+		rule.nextEvent = 0
+		rule.active = true
+		return nil, nil
+	}
+
+	// use the axis value and the repeat rate to set a target time until the next event
+	strength := 1.0 - rule.Input.GetAxisStrength(event.Value)
+	rate := int64(LerpInt(rule.RepeatRateMax, rule.RepeatRateMin, strength))
+	rule.nextEvent = time.Duration(rate * int64(time.Millisecond))
+	rule.active = true
+
 	return nil, nil
 }
 
 // TimerEvent returns an event when enough time has passed (compared to the last recorded axis value)
 // to emit an event.
 func (rule *MappingRuleAxisToButton) TimerEvent() *evdev.InputEvent {
-	// This is tighter coupling than we'd like, but it will do for now.
-	// TODO: maybe it would be better to just be more declarative about event types and their inputs and outputs.
-	if rule.lastValue < rule.Input.DeadzoneStart {
-		rule.lastEvent = time.Now()
+	// If we pressed the button last tick, release it before doing anything else
+	if rule.pressed {
+		rule.pressed = false
+		return rule.Output.CreateEvent(0, nil)
+	}
+
+	// If we should not emit another event,
+	// we just update lastEvent for station keeping
+	if rule.nextEvent == NoNextEvent {
+		rule.lastEvent = rule.clock.Now()
 		return nil
 	}
 
-	// calculate target time until next event press
-	//	nextEvent := rule.LastEvent + (rule.LastValue)
+	if rule.clock.Now().Compare(rule.lastEvent.Add(rule.nextEvent)) > -1 {
+		rule.lastEvent = rule.clock.Now()
+		rule.pressed = true
 
-	// TODO: figure out what the condition should be
-	if false {
-		// TODO: emit event
-		rule.lastEvent = time.Now()
+		// The default case here is to leave nextEvent at whatever
+		// it has been set to by MatchEvent. Since nextEvent is a delta,
+		// this will naturally cause the repeat to happen
+		if !rule.repeat {
+			rule.nextEvent = NoNextEvent
+		}
+
+		return rule.Output.CreateEvent(1, nil)
 	}
 
 	return nil
 }
+
+func (rule *MappingRuleAxisToButton) GetOutputDevice() *evdev.InputDevice {
+	return rule.Output.Device
+}