sinProject-Inc/talk

type KeyEventHandlerParams = {
    alt?: boolean
    shift?: boolean
    control?: boolean
    code?: string
}

export class KeyboardShortcutHandler {
    private _event_handler: (event: KeyboardEvent) => void
    private _params: KeyEventHandlerParams
    private _callback: () => void

    public constructor(params: KeyEventHandlerParams, callback: () => void) {
        this._params = params
        this._callback = callback

        this._event_handler = this._create_event_handler()

        this._set_event_handler()
    }

    private _create_event_handler(): (event: KeyboardEvent) => void {
        const handler = (event: KeyboardEvent): void => {
            const should_process_event = this._should_process_event(event)

            if (!should_process_event) return

            event.preventDefault()

            this._callback()
        }

        return handler
    }

    private _should_process_event(event: KeyboardEvent): boolean {
        const { alt = false, shift = false, control = false, code = null } = this._params
        const is_control_pressed = event.ctrlKey || event.metaKey

        const is_alt_matching = alt === event.altKey
        const is_shift_matching = shift === event.shiftKey
        const is_control_matching = control === is_control_pressed
        const is_code_matching = code === event.code

        const should_process =
            is_alt_matching && is_shift_matching && is_control_matching && is_code_matching

        return should_process
    }

    private _set_event_handler(): void {
        this.remove_event_handler()

        if (!this._params) return

        window.addEventListener('keydown', this._event_handler)
    }

    public remove_event_handler(): void {
        window.removeEventListener('keydown', this._event_handler)
    }
}