// This file handles the "Confirm instance details" dialog

import { parseHost } from "./add_an_instance.mjs";
import { FormDialog, ONCE } from "./dialog.mjs";
import { findButtonOrFail, findFormOrFail, findImageOrFail, findInputOrFail, findOptionOrFail, findSelectOrFail } from "./dom.mjs";
import knownSoftware from "./known_software.mjs";
import { Instance } from "./storage_manager.mjs";

const blankImage = "data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==";

export function mergeHost(host: string, secure: boolean): string {
    return `http${secure ? "s" : ""}://${host}`;
}

export type InstanceDetailsDialogData = {
    name: string,
    host: string,
    hostSecure: boolean,
    software: string,
    iconURL: string | null,
    preferredFor: string[],
};

export function dialogDetailsFromInstance(instance: Instance): InstanceDetailsDialogData {
    const host = parseHost(instance.origin)!;
    return {
        name: instance.name,
        host: host.host,
        hostSecure: host.secure,
        software: instance.software,
        iconURL: instance.iconURL ?? null,
        preferredFor: instance.preferredFor,
    };
}

export function dialogDetailsToInstance(data: InstanceDetailsDialogData, instance: Partial<Instance>): Instance {
    instance.name = data.name;
    instance.origin = mergeHost(data.host, data.hostSecure);
    instance.software = data.software;
    instance.iconURL = data.iconURL ?? undefined;
    instance.preferredFor = data.preferredFor;
    return instance as Instance;
}

export class InstanceDetailsDialog extends FormDialog {
    protected instanceName: HTMLInputElement;
    protected instanceHost: HTMLInputElement;
    protected instanceHostSecure: HTMLInputElement;
    protected instanceSoftware: HTMLSelectElement;
    protected instanceIcon: HTMLImageElement;
    protected closeButton: HTMLButtonElement;
    protected defaultsList?: {
        list: HTMLSelectElement,
        removeButton: HTMLButtonElement,
        noDefaultsOption: HTMLOptionElement,
    };

    constructor(dialog: HTMLDialogElement, initializeDOM: boolean = true) {
        super(dialog, findFormOrFail(dialog, ".instanceDetailsForm"));

        this.instanceName = findInputOrFail(this.form, "#instanceName");
        this.instanceHost = findInputOrFail(this.form, "#instanceHost");
        this.instanceHostSecure = findInputOrFail(this.form, "#instanceHostSecure");
        this.instanceSoftware = findSelectOrFail(this.form, "#instanceSoftware");
        this.instanceIcon = findImageOrFail(this.form, "#instanceIcon");
        this.closeButton = findButtonOrFail(this.form, ".close");
        try {
            this.defaultsList = {
                list: findSelectOrFail(this.form, "#defaultsList"),
                removeButton: findButtonOrFail(this.form, "#removeDefaults"),
                noDefaultsOption: findOptionOrFail(this.form, "#noDefaults"),
            };
        } catch {
            this.defaultsList = undefined;
        }

        if (initializeDOM) this.initializeDOM();
    }

    protected override initializeDOM() {
        super.initializeDOM();

        for (const [name, software] of Object.entries(knownSoftware.software)) {
            const option = new Option(software.name, name);
            this.instanceSoftware.appendChild(option);
        }

        this.instanceIcon.src = blankImage;

        this.closeButton.addEventListener("click", e => this.close());

        if (this.defaultsList) {
            this.defaultsList.list.addEventListener("change", e => this.#handleListSelectionChange());
            this.defaultsList.removeButton.addEventListener("click", e => this.#removeSelectedListOptions());
        }
    }

    #getRemainingListOptions(): string[] {
        if (!this.defaultsList) return [];

        const items: string[] = [];

        for (const option of this.defaultsList.list.options) {
            if (option == this.defaultsList.noDefaultsOption) continue;
            items.push(option.value);
        }

        return items;
    }

    #removeSelectedListOptions() {
        if (!this.defaultsList) return;

        // Copy using spread because this breaks when the list changes mid-iteration
        for (const option of [...this.defaultsList.list.selectedOptions]) {
            option.remove();
        }

        this.#handleListChange();
    }

    #populateDefaultsList(items: string[]) {
        if (!this.defaultsList) return;

        while (this.defaultsList.list.children.length > 1)
            this.defaultsList.list.removeChild(this.defaultsList.list.lastChild!);

        for (const item of items) {
            const option = document.createElement("option");
            option.value = item;
            option.innerText = knownSoftware.software[item]?.name ?? knownSoftware.groups[item]?.name ?? item;
            this.defaultsList.list.appendChild(option);
        }

        this.#handleListChange();
    }

    #handleListChange() {
        this.#handleListEmpty();
        this.#handleListSelectionChange();
    }

    #handleListSelectionChange() {
        if (!this.defaultsList) return;
        this.defaultsList.removeButton.disabled = this.defaultsList.list.selectedOptions.length === 0;
    }

    #handleListEmpty() {
        if (!this.defaultsList) return;
        if (this.defaultsList.list.children.length == 1) {
            this.defaultsList.noDefaultsOption.removeAttribute("hidden");
        } else {
            this.defaultsList.noDefaultsOption.setAttribute("hidden", "");
        }
    }

    #handleSubmit(data: InstanceDetailsDialogData, resolve: (data: InstanceDetailsDialogData) => void) {
        this.form.addEventListener("submit", e => {
            data.name = this.instanceName.value;
            data.host = this.instanceHost.value;
            data.hostSecure = this.instanceHostSecure.checked;
            data.software = this.instanceSoftware.value;
            data.preferredFor = this.#getRemainingListOptions();

            resolve(data);
            this.close();
        }, ONCE);
    }

    async present(data: InstanceDetailsDialogData): Promise<InstanceDetailsDialogData> {
        this.instanceName.value = data.name;
        this.instanceHost.value = data.host;
        this.instanceHostSecure.checked = data.hostSecure;
        this.instanceSoftware.value = data.software;
        this.instanceIcon.src = data.iconURL ?? blankImage;
        this.#populateDefaultsList(data.preferredFor);

        return new Promise((resolve, reject) => {
            this.cancelOnceClosed(reject);
            this.#handleSubmit(data, resolve);
            this.open();
        });
    }
}