package input

import (
	"errors"
	"strings"
)

const (
	InterruptAllKeys    = "all"
	InterruptCommonKeys = "common"
	InterruptCustomKeys = "custom"
	MaxInterruptionKeys = 64
)

// InterruptionSettings selects individual keys, independently of key echo and
// command bindings. Reader commands retain their own explicit cancellation.
type InterruptionSettings struct {
	Mode string   `toml:"mode"`
	Keys []string `toml:"keys"`
}

func (settings InterruptionSettings) Validate() error {
	switch settings.Mode {
	case InterruptAllKeys, InterruptCommonKeys, InterruptCustomKeys:
	default:
		return errors.New("choose a valid speech interruption mode")
	}
	if len(settings.Keys) > MaxInterruptionKeys {
		return errors.New("too many speech interruption keys")
	}
	if settings.Mode == InterruptCustomKeys && len(settings.Keys) == 0 {
		return errors.New("record at least one speech interruption key")
	}
	seen := make(map[string]bool, len(settings.Keys))
	for _, name := range settings.Keys {
		key := strings.ToLower(name)
		if name == "" || len(name) > 128 || seen[key] {
			return errors.New("speech interruption keys must have unique, valid key names")
		}
		for _, character := range name {
			if character != '_' && !(character >= 'a' && character <= 'z') &&
				!(character >= 'A' && character <= 'Z') && !(character >= '0' && character <= '9') {
				return errors.New("invalid speech interruption key name")
			}
		}
		seen[key] = true
	}
	return nil
}

func (settings InterruptionSettings) ShouldInterrupt(event Event) bool {
	if !event.Pressed {
		return false
	}
	switch settings.Mode {
	case InterruptCommonKeys:
		switch event.Name {
		case "Control_L", "Control_R", "Return", "KP_Enter", "space", "KP_Space", "Escape":
			return true
		}
		return false
	case InterruptCustomKeys:
		for _, name := range settings.Keys {
			if strings.EqualFold(name, event.Name) || name == "Tab" && event.Name == "ISO_Left_Tab" {
				return true
			}
		}
		return false
	default:
		return true
	}
}