class NoblogsCf_FormKnownError extends Error{
}

class NoblogsCf_Form{
    /*
     * The button used to send the form message.
     */
    #button = document.getElementById("noblogscf-form-button");
    
    /*
     * True if the message is being sent, false otherwise.
     */
    #sending = false;
    
    /*
     * The element containing the message sending status. Initially
     * empty, it starts to change after clicking on the button.
     */
    #status = document.getElementById("noblogscf-form-status");
    
    /*
     * The status text.
     */
    #statusText = document.getElementById("noblogscf-form-status-text");
    
    /*
     * Shows the form and attaches an action to the activation of the
     * button.
     */
    constructor(){
        // hide the instructions for users with Javascript disabled and show the form
        document.getElementById("noblogscf-no-javascript-instructions").style.display = "none";
        
        // set the button type to "button" to prevent it from submitting the form
        this.#button.type = "button";
        
        // send the message when the button is activated
        this.#button.addEventListener("click", this.#sendMessage.bind(this));
    }
    
    /*
     * Encrypts and sends the form message if it isn't already being
     * sent.
     */
    async #sendMessage(){
        // if the message isn't being sent
        if(this.#sending === false){
            try{
                // the message is being sent
                this.#sending = true;
                this.#setStatus(wp.i18n.__("Sending…", "noblogs-contact-form"));
                
                // disable the button to prevent the user to try to send the message again while it is being sent
                this.#button.disabled = true;
                
                // set the unencrypted message
                const unencryptedMessage = document.getElementById("noblogscf-form-message").value;
                
                // check the unencrypted message isn't empty
                if(unencryptedMessage.length === 0){
                    throw new NoblogsCf_FormKnownError(wp.i18n.__("The message is empty.", "noblogs-contact-form"));
                }
                
                // encrypt the message
                var encryptedMessage = null;
                try{
                    encryptedMessage = await openpgp.encrypt({
                        message: await openpgp.createMessage({"text": unencryptedMessage}),
                        encryptionKeys: await openpgp.readKey({"armoredKey": noblogscfPhpVars.pgpPublicKey})
                    });
                }
                catch(error){
                    if(error.message === "Error encrypting message: Primary key is expired"){
                        throw new NoblogsCf_FormKnownError(wp.i18n.__("The PGP public key configured by the site manager has expired.", "noblogs-contact-form"));
                    }
                    else{
                        throw new NoblogsCf_FormKnownError(wp.i18n.__("The site manager has configured an invalid PGP public key.", "noblogs-contact-form"));
                    }
                }
                
                // send the request
                var response = null;
                try{
                    response = await window.fetch(noblogscfPhpVars.requestURL, {
                        "method": "post",
                        "headers": {
                            "Content-Type": "application/x-www-form-urlencoded",
                        },
                        "body": "_ajax_nonce=" + noblogscfPhpVars.nonce + "&action=noblogscf_send_message_with_javascript&message=" + encodeURIComponent(encryptedMessage)
                    });
                }
                catch(error){
                    throw new NoblogsCf_FormKnownError(wp.i18n.__("Network error.", "noblogs-contact-form"))
                }
                
                // the message was sent
                if(response.ok && response.status === 200){
                    this.#setStatus(wp.i18n.__("Sent successfully!", "noblogs-contact-form"));
                }
                // the message was not sent
                else{
                    const responseBody = await response.json();
                    throw new NoblogsCf_FormKnownError(responseBody.data.error);
                }
            }
            catch(error){
                // known error
                if(error instanceof NoblogsCf_FormKnownError){
                    this.#setErrorStatus(error.message);
                }
                // unknown error
                else{
                    this.#setErrorStatus(wp.i18n.__("Unknown.", "noblogs-contact-form"));
                }
                
                // re-enable the button to allow the user to try to send the message again
                this.#button.disabled = false;
            }
                    
            // the message isn't being sent anymore
            this.#sending = false;
        }
    }
    
    /*
     * Sets the status text to an error status.
     */
    #setErrorStatus(errorText){
        // translators: "%s" is replaced with the reason why sending the message failed
        this.#setStatus(wp.i18n.sprintf(wp.i18n.__("Sending failed. Reason: %s", "noblogs-contact-form"), errorText));
    }
    
    /*
     * Sets the status text.
     */
    #setStatus(text){
        // show the status
        this.#status.style.display = "block";
        
        // change the status text
        this.#statusText.innerHTML = text;
    }
};

// instantiate the class on the window load event
window.addEventListener("load", () => {
    const noblogsCfForm = new NoblogsCf_Form();
});