"use strict";

function save_thumbnail_to_dom(win_id, win_html) {
    var new_id = null;
    var div_container = null;
    var thumbnails_container = null;
    var thumbnail_is_cached = null;
    var cached_thumb = null;
    var cached_thumb_child_array = null;
    var i = null;
    var thumbnail_elem = null;

    //create the DOM containers to hold cached thumbnails and the thumbnails' top parent container.
    //if you create the thumbnail's container, then the top parent container is automatically created as well.
    //if either of these DOM containers already exist, they will not be recreated. 
    //instead, the existing objects are returned by the function.
    thumbnails_container = make_thumbnails_container(); //returns the thumbnail cache container in the DOM

    //create a string which will serve as a unique ID value for the div container holding the thumbnail HTML.
    //make a div object to serve as the thumbnail's parent container.
    //modify its ID attribute to make it unique.
    //store the thumbnail's ID, and the ID the of the thumbnails web window as custom attributes.
    //set the container so that its not displayed.
    //place the thumbnail's HTML into the container
    new_id = win_id + "_in_DOM";
    div_container = document.createElement("div");
    div_container.setAttribute("id", new_id + "_container");
    div_container.setAttribute("name", "cached_DOM_thumbnails");
    div_container.setAttribute("data-thumbnail_id_", win_id + "_is_cached");
    div_container.setAttribute("data-win_id", win_id.replace("copied_node_", ""));
    div_container.style.display = "none";
    div_container.style.position = "fixed";
    div_container.style.border = "2px none rgb(0, 0, 255)";

    div_container.innerHTML = win_html;

    //2023-09-19:
    //tried chanding every child id attribute. It caused errors.
    //Reset the code back to as it was from a backup file.
    //Will try again later....
    //2023-09-19:
    //Set the child node of the div_container which is the stored web window thumbnail HTML.
    //change its ID attribute to be unique. A thumbnail located elsewhere in the
    //DOM(inside the 'single_thumbnail_contaier' object), may already exist.
    if (div_container.hasChildNodes() === true) {
        cached_thumb = div_container.childNodes[0];
        if (cached_thumb !== null) {
            cached_thumb_child_array = cached_thumb.getElementsByTagName("*");
            for (i = 0; i < cached_thumb_child_array.length; i++) {
                thumbnail_elem = cached_thumb_child_array[i];
                thumbnail_elem.setAttribute("id", (thumbnail_elem.id + "_is_cached")); //change the cached thumbnail's ID attribute to be unique
            }
        }
    }
    
    //set the child node of the div_container which is the stored web window thumbnail HTML.
    //change its ID attribute to be unique. A thumbnail located elsewhere in the
    //DOM(inside the 'single_thumbnail_contaier' object), may already exist.
    /*
    if (div_container.hasChildNodes() === true) {
        cached_thumb = div_container.childNodes[0];
        if (cached_thumb !== null) {
            cached_thumb.setAttribute("id", (cached_thumb.id + "_is_cached")); //change the cached thumbnail's ID attribute to be unique
        }
    }
    */

    //check to see if the cached thumbnail's parent container object exists in the DOM.
    //If the thumbnail's container exists, then so does the thumbnail's HTML -- we don't need to check
    //for the actual cached thumbnail specifically. 
    thumbnail_is_cached = thumbnail_exists_in_dom_cache(win_id + "_in_DOM_container"); //the argument is the ID attribute of the thumbnail's container object

    //console.log("thumbnail_is_cached");

    if (thumbnail_is_cached === false) {
        if (thumbnails_container !== null) {
            thumbnails_container.appendChild(div_container); //add the container object and its thumbnail HTML into the cached thumbnails collection
        }
    }

    //get the cached thumbnail object via its parent container ID.
    //if the thumbnail object is not null (it exists), then
    //set the expiration date to 1.5 days. Time given until
    //expiration date is input as a number of days. The expiration
    //date provides the date as a number of seconds.
    if (div_container.hasChildNodes() === true) {
        cached_thumb = div_container.childNodes[0]; //get the thumbnail object in cache
        if (cached_thumb !== null) {
            //2023-06-24: Don't remove this. It may be used later.
            //store the expiration date in the thumbnail as an HTML attribute. 
            //In this case, the expiration date expires in 1.5 days.The stored 
            //expiration date is a numeric value representing a date in seconds.
            set_thumbnail_cache_expiration_date(cached_thumb.id, 0); 
        }
    }
}



//This function creates the immediate parent container for cached thumbnails.
//the immediate parent container is stored within the thumbnails' top parent
//node container. If that top parent doesn't exist, create it.
function make_thumbnails_container() {
    var div_id = null;
    var div_id_2 = null;
    var thumbnails_container = null;
    var thumbnails_top_container = null;
    var top_container = null;
    var single_thumbnail_container = null;

    div_id = "thumbnail_top_container";
    thumbnails_top_container = document.getElementById(div_id);

    div_id_2 = "cached_thumbnails";
    thumbnails_container = document.getElementById(div_id_2);

    if (thumbnails_top_container !== null) {
        if (thumbnails_container !== null) {
            thumbnails_top_container.appendChild(thumbnails_container);
        }
        else {
            single_thumbnail_container = document.createElement("div");
            single_thumbnail_container.setAttribute("id", "cached_thumbnails");
            thumbnails_top_container.appendChild(single_thumbnail_container);
        }
    }
    else {
        top_container = document.createElement("div");
        top_container.setAttribute("id", "thumbnail_top_container");
        document.body.appendChild(top_container);
    }

    return thumbnails_container;
}


//this function returns a boolean value of true if the thumbnail already exists in the DOM.
//otherwise, it returns false. This prevents duplicate cached thumbnails from being
//added to the DOM
function thumbnail_exists_in_dom_cache(thumbnail_id) {
    var cached_thumbnails = null;
    var thumbnail = null;
    var thumb_id = null;
    var i = null;
    var exists = null;

    exists = false;
    cached_thumbnails = document.getElementById("cached_thumbnails");
    if (cached_thumbnails !== null) {
        //alert("cached_thumbnails elem exists");
        if (cached_thumbnails.hasChildNodes() === true) {
            //alert("has child nodes");
            for (i = 0; i < cached_thumbnails.childElementCount; i++) {
                thumbnail = cached_thumbnails.childNodes[i];
                //alert(thumbnail.id);
                //alert(thumbnail_id);
                if (thumbnail !== null) {
                    //alert(thumbnail.hasAttribute("id"));
                    if (thumbnail.hasAttribute("id") === true) {
                        thumb_id = thumbnail.getAttribute("id");
                        if (thumb_id === thumbnail_id) { 
                            exists = true;
                            //alert("test");
                            return exists;
                        }
                    }
                }
            }
        }
    }
    return exists;
}




function set_thumbnail_cache_expiration_date(thumbnail_id, num_of_days) {
    var thumbnail = null;
    var expire_date = null;
    var num_days_until_expiration = null;
    var days_until_expiration = null;
    var date_in_seconds = null;
    var default_expiration_days = null;
    var grace_period = null;
    var seconds_per_day = null;
    var seconds_until_expiration = null;

    //if the expiration time length in days is invalid, or not specified, default to 2.0 days.
    default_expiration_days = 2.0;

    //get the time until expiration in days.
    //if the number of days is not a valid number
    //that is equal to or greater than 0, then
    //then the number of days defaults to 2.0.
    num_days_until_expiration = num_of_days;
    if (typeof num_days_until_expiration === "number") {
        if (num_days_until_expiration >= 0) {
            days_until_expiration = num_days_until_expiration; //number of days passed in as an argument is a valid numver greater or equal to 0.
        }
        else {
            days_until_expiration = default_expiration_days; //number of days specified is less than 0.
        }
    }
    else {
        days_until_expiration = default_expiration_days; //the number of days specified is not a number
    }

    thumbnail = document.getElementById(thumbnail_id);
    if (thumbnail !== null) {
        expire_date = calculate_expiration_date(days_until_expiration); //today's date in seconds + number of days until expiration.
        grace_period = 10.0; //provide a 10 second grace period before the thumbnail expires. Used mostly for testing.
        date_in_seconds = parseFloat(get_date_in_seconds());
        seconds_per_day = 60 * 60 * 24;
        seconds_until_expiration = (seconds_per_day * days_until_expiration); //this sets exiration date to 2 days from now (in seconds)
        expire_date = parseFloat(date_in_seconds) + parseFloat(grace_period) + parseFloat(seconds_until_expiration); //add today's date in seconds to the seconds until expiration to get the expiration date.

        thumbnail.setAttribute("data-thumbnail_cache_expiration_date", expire_date); //set expiration date in an html attribute of the thumbnail.
    }
    else {
        expire_date = calculate_expiration_date(days_until_expiration); //today's date in seconds + number of days until expiration.
        grace_period = 10.0; //provide a 10 second grace period before the thumbnail expires. Used mostly for testing.
        date_in_seconds = parseFloat(get_date_in_seconds());
        seconds_per_day = 60 * 60 * 24;
        seconds_until_expiration = (seconds_per_day * days_until_expiration); //this sets exiration date to 2 days from now (in seconds)
        expire_date = parseFloat(date_in_seconds) + parseFloat(grace_period) + parseFloat(seconds_until_expiration); //add today's date in seconds to the seconds until expiration to get the expiration date.
    }

    //alert("Time till expiration: " + (expire_date - date_in_seconds));

    return expire_date;
}

//2023-06-24: get the expiration date stored in a thumbnail object's HTML attribute.
//if the attribute exists and is numeric return that date (in seconds). Otherwise, return null.
function get_thumbnail_cache_expiration_date(thumbnail_id) {
    var thumbnail = null;
    var expires = null;

    thumbnail = document.getElementById(thumbnail_id);
    if (thumbnail !== null) {
        if (thumbnail.hasAttribute("data-expiration_date") === true) {
            expires = thumbnail.getAttribute("data-expiration_date");
            if (expires !== null && !isNaN(expires) === true && expires !== undefined && expires !== "") {
                return expires;
            }
            else {
                //in this conditional, the 'expires' variable is either non-existent, or
                //does not have a numerical value, or has the value of null. So,
                //set the expiration date into a new HTML attribute of "data-expiration_date".
                expires = set_thumbnail_cache_expiration_date(thumbnail_id, 2.0);
                return expires;
            }
        }
        else {
            //the HTML attribute doesn't exist in this object. Add it.
            expires = set_thumbnail_cache_expiration_date(thumbnail_id, 2.0);
            return expires;
        }
    }
    return expires;
}


//2023-06-24: depending on the number of days
//specified in this function's argument, this function
//returns the expiration date in seconds. 
//Defaults to 2 days if the argument isn't a number above -1.0
function calculate_expiration_date(num_days_until_expiration) {
    var date_in_seconds = null;
    var seconds_per_day = null;
    var seconds_until_expiration = null;
    var expiration_date_in_seconds = null;
    var days_until_expiration = null;

    if (typeof num_days_until_expiration === "number") {
        if (num_days_until_expiration >= 0) {
            days_until_expiration = num_days_until_expiration;
        }
        else {
            days_until_expiration = 2.0;
        }
    }
    else {
        days_until_expiration = 2.0;
    }
    
    date_in_seconds = parseFloat(get_date_in_seconds());
    seconds_per_day = 60 * 60 * 24;
    seconds_until_expiration = seconds_per_day * days_until_expiration; //this sets exiration date to 2 days from now (in seconds)
    expiration_date_in_seconds = parseFloat(date_in_seconds) + parseFloat(seconds_until_expiration); //add today's date in seconds to the seconds until expiration to get the expiration date.

    return expiration_date_in_seconds;
}


//gets the date in milliseconds by default. Divide by 1,000 to get seconds.
function get_date_in_seconds() {
    var d = null;
    var d_now = null;

    d = new Date(Date.now());
    d_now = parseFloat(d.getTime());
    d_now = Math.round(d_now / 1000);
    ////console.log(d_now);

    return d_now;
}



function is_cached_thumbnail_in_DOM_expired(thumbnail_id) {
    var thumbnail = null;
    var todays_date = null;
    var attribute_name = null;
    var expire_date = null;
    var is_expired = null;


    todays_date = parseFloat(get_date_in_seconds());

    is_expired = null;
    //get thumbnail object by its ID
    thumbnail = document.getElementById(thumbnail_id); 
    if (thumbnail !== null) {
        attribute_name = "data-thumbnail_cache_expiration_date";
        //When expiration dates are stored in HTML 
        //attributes, they may be retrieved by accessing this 
        //thumbnail's attribute value. 
        if (thumbnail.hasAttribute(attribute_name) === true) {
            expire_date = thumbnail.getAttribute(attribute_name);
            if (!isNaN(expire_date) === true) {
                expire_date = parseFloat(expire_date);
                if (!isNaN(todays_date) === true) {
                    if (todays_date >= expire_date) {
                    //the thumbnail is expired by:
                        console.log("Thumbnail expired by " + (todays_date - expire_date) + " seconds.");
                        is_expired = true;
                        return is_expired;
                    }
                    else if (todays_date < expire_date) {
                    //the thumbnail is valid for: 
                        console.log("Thumbnail is valid for " + (expire_date - todays_date) + " seconds.");
                        is_expired = false;
                        return is_expired;
                    }
                }
            }
        }
    }
    return is_expired;
}



function position_cached_thumbnail_to_web_window(win_id) {
    var win = null;
    var thumbnail = null;
    var thumbnail_parent_container_id = null;
    var thumbnail_parent = null;

    win = document.getElementById(win_id);
    if (win !== null) {
        thumbnail = document.getElementById("copied_node_" + win_id + "_is_cached");
        thumbnail_parent_container_id = "copied_node_" + win_id + "_in_DOM_container";
        thumbnail_parent = document.getElementById(thumbnail_parent_container_id);
        if (thumbnail_parent !== null) {
            if (thumbnail !== null) {
                remove_elem_animations(thumbnail.id);

                thumbnail_parent.style.top = (parseFloat(win.offsetTop) + 29) + "px";
                thumbnail_parent.style.left = (parseFloat(win.offsetLeft) + 28) + "px";
                thumbnail_parent.style.width = ((parseFloat(thumbnail.style.width) * 0.5) + 3) + "px";
                thumbnail_parent.style.height = ((parseFloat(thumbnail.style.height) * 0.5) + 3) + "px";
                thumbnail.style.top = (parseFloat(win.scrollTop)) + "px";
                thumbnail.style.left = (parseFloat(win.offsetLeft)) + "px";

                //2023-06-26: If window icons still have a blue background from user interaction,
                //these two lines remove those backgrounds if they exist on a thumbnail object.
                remove_bg_color("copied_node_" + win_id + "_tbl_0000_tr_0000_td_0002");
                remove_bg_color("copied_node_" + win_id + "_tbl_0000_tr_0000_td_0000");
            }
        }
    }
}


/*
function is_object_thumbnail_window(win_id) {
    var win = null;
    var is_thumbnail = null;
    var attr = null
    var r_value = null;

    win = document.getElementById(win_id);

    if (win !== null) {
        if (win.hasAttribute("data-is_thumbnail_object") === true) {
            is_thumbnail = win.getAttribute("data-is_thumbnail_object");
            if (is_thumbnail !== null) {
                if (is_thumbnail === "true" || is_thumbnail === true) {
                    r_value = true;
                }
                else if (r_value === "false" || r_value === false) {
                    r_value = false;
                }
                else {
                    r_value = null;
                }
            }
        }
        else {
            win.setAttribute("data-is_thumbnail_object", "false"); 
            r_value = false;
        }
    }

    return r_value;
}


function set_object_thumbnail_true(win_id) {
    var win = null;

    win = document.getElementById(win_id);

    if (win !== null) {
    win.setAttribute("data-is_thumbnail_object", "true");
    }
}


function set_object_thumbnail_false(win_id) {
    var win = null;

    win = document.getElementById(win_id);

    if (win !== null) {
        win.setAttribute("data-is_thumbnail_object", "false");
    }
}
*/