package input

import (
	"runtime"
	"strings"
)

func PressKey(key, action string, modifiers []string) error {
	vk, ok := vkCode(key)
	if !ok {
		return ErrBadKey
	}

	runtime.LockOSThread()
	defer runtime.UnlockOSThread()
	if err := attachInputDesktop(); err != nil {
		return err
	}

	modVKs := make([]uint16, 0, len(modifiers))
	for _, mod := range modifiers {
		modVK, ok := vkCode(mod)
		if !ok {
			return ErrBadKey
		}
		modVKs = append(modVKs, modVK)
	}

	for _, modVK := range modVKs {
		if err := sendKeyEvent(modVK, false); err != nil {
			return err
		}
	}

	switch strings.ToLower(strings.TrimSpace(action)) {
	case "down":
		if err := sendKeyEvent(vk, false); err != nil {
			return err
		}
	case "up":
		if err := sendKeyEvent(vk, true); err != nil {
			return err
		}
	default:
		if err := sendKeyEvent(vk, false); err != nil {
			return err
		}
		if err := sendKeyEvent(vk, true); err != nil {
			return err
		}
		for i := len(modVKs) - 1; i >= 0; i-- {
			if err := sendKeyEvent(modVKs[i], true); err != nil {
				return err
			}
		}
		return nil
	}
	return nil
}

func sendKeyEvent(vk uint16, keyUp bool) error {
	flags := uint32(0)
	if keyUp {
		flags = keyeventfKeyup
	}
	inputs := []keybdInput{{Type: inputKeyboard, Vk: vk, Flags: flags}}
	return sendKeys(inputs)
}