import {DidFailLoadEvent, ipcRenderer, PageFaviconUpdatedEvent, UpdateTargetUrlEvent} from "electron";
import Service from "../../src/Service";
import {IconProperties, IconSet, SpecialPages} from "../../src/Meta";
import Config from "../../src/Config";

const appInfo: {
    title?: string;
} = {};
let icons: IconProperties[] = [];

let services: (FrontService | undefined)[] = [];
let selectedServiceId: number | null = null;
let securityButton: HTMLElement | null = null,
    homeButton: HTMLElement | null = null,
    forwardButton: HTMLElement | null = null,
    backButton: HTMLElement | null = null,
    refreshButton: HTMLElement | null = null;
let addButton, settingsButton;
let specialPages: SpecialPages | null = null;
let urlPreview: HTMLElement | null = null;
let serviceSelector: HTMLElement | null = null;

// Service reordering
let lastDragPosition: HTMLElement | null = null;
let oldActiveService: number | null = null;


ipcRenderer.on('data', (
    event,
    appTitle: string,
    iconSets: IconSet[],
    activeServiceId: number,
    _specialPages: SpecialPages,
    config: Config,
) => {
    // App info
    appInfo.title = appTitle;

    // Icons
    icons = [];
    for (const set of iconSets) {
        icons.push(...set);
    }

    // Special pages
    specialPages = _specialPages;

    console.log('Updating services ...');
    services = config.services;

    const nav = document.querySelector('#service-selector');
    if (nav) {
        while (nav.children.length > 0) {
            nav.removeChild(nav.children[0]);
        }
    }

    const serviceContainer = document.querySelector('#services');
    if (serviceContainer) {
        serviceContainer.querySelectorAll(":scope > webview").forEach(w => serviceContainer.removeChild(w));
    }

    for (let i = 0; i < services.length; i++) {
        createServiceNavigationElement(i);
    }

    // Init drag last position
    lastDragPosition = document.getElementById('service-last-drag-position');
    if (lastDragPosition) {
        lastDragPosition.addEventListener('dragover', () => {
            const index = services.length;
            if (draggedId !== index && draggedId !== index - 1) {
                resetDrag();
                lastDragTarget = index;
                lastDragPosition?.classList.remove('hidden');
                lastDragPosition?.classList.add('drag-target');
            }
        });
    }

    // Set active service
    if (activeServiceId < 0 || activeServiceId >= services.length) {
        activeServiceId = 0;
    }
    setActiveService(activeServiceId);

    // Url preview element
    urlPreview = document.getElementById("url-preview");
    if (urlPreview) {
        const _urlPreview = urlPreview;
        urlPreview.addEventListener('mouseover', () => {
            if (_urlPreview.classList.contains('right')) {
                _urlPreview.classList.remove('right');
            } else {
                _urlPreview.classList.add('right');
            }
        });
    }

    // History nav buttons
    const buttons: { [k: string]: HTMLElement | null } = {
        securityButton: securityButton,
        homeButton: homeButton,
        backButton: backButton,
        forwardButton: forwardButton,
        refreshButton: refreshButton,
    };
    for (const k in buttons) {
        if (config[k]) buttons[k]?.classList.remove('hidden');
        else buttons[k]?.classList.add('hidden');
    }

    // Other elements
    serviceSelector = document.getElementById('service-selector');

    // Navbar size
    document.documentElement.style.setProperty('--nav-width', config.bigNavBar ? '64px' : '48px');
});

ipcRenderer.on('load-service-home', (event, serviceId: number) => {
    const service = services[serviceId];
    if (!service) throw new Error('Service doesn\'t exist.');

    service.view?.loadURL(service.url)
        .catch(console.error);
});

ipcRenderer.on('reload-service', (event, serviceId: number) => {
    reloadService(serviceId);
});

ipcRenderer.on('unload-service', (event, serviceId: number) => {
    unloadService(serviceId);
});

ipcRenderer.on('reset-service-zoom-level', (event, serviceId: number) => {
    const service = services[serviceId];
    if (service?.view) {
        service.view.setZoomFactor(1);
        service.view.setZoomLevel(0);
    }
});

ipcRenderer.on('zoom-in-service', (event, serviceId: number) => {
    const service = services[serviceId];
    if (service?.view) {
        service.view.setZoomLevel(service.view.getZoomLevel() + 1);
    }
});

ipcRenderer.on('zoom-out-service', (event, serviceId: number) => {
    const service = services[serviceId];
    if (service?.view) {
        service.view.setZoomLevel(service.view.getZoomLevel() - 1);
    }
});

function removeServiceFeatures(id: number): Element | null {
    // Remove nav
    const nav = document.querySelector('#service-selector');
    let oldNavButton: HTMLElement | null = null;
    let nextSibling: Element | null = null;
    if (nav) {
        oldNavButton = nav.querySelector('li:nth-of-type(' + (id + 1) + ')');
        if (oldNavButton) {
            nextSibling = oldNavButton.nextElementSibling;
            nav.removeChild(oldNavButton);
        }
    }

    // Remove webview
    const service = services[id];
    if (service) {
        const view = service.view;
        if (view) document.querySelector('#services')?.removeChild(view);
    }

    return nextSibling;
}

ipcRenderer.on('updateService', (e, id: number | null, data: Service) => {
    if (id === null) {
        console.log('Adding new service');
        services.push(data);
        createServiceNavigationElement(services.length - 1);
    } else {
        console.log('Updating existing service', id);
        const nextSibling = removeServiceFeatures(id);

        // Create new service
        services[id] = data;
        createServiceNavigationElement(id, nextSibling);
        if (selectedServiceId === id) {
            setActiveService(id);
        }
    }
});

ipcRenderer.on('reorderService', (e, serviceId: number, targetId: number) => {
    const oldServices = services;
    services = [];

    let newId = targetId;

    for (let i = 0; i < targetId; i++) {
        if (i !== serviceId) {
            services.push(oldServices[i]);
            if (i === oldActiveService) newId = services.length - 1;
        }
    }
    services.push(oldServices[serviceId]);
    for (let i = targetId; i < oldServices.length; i++) {
        if (i !== serviceId) {
            services.push(oldServices[i]);
            if (i === oldActiveService) newId = services.length - 1;
        }
    }

    if (serviceSelector) {
        serviceSelector.innerHTML = '';
    }
    for (let i = 0; i < services.length; i++) {
        const service = services[i];
        if (service) service.li = undefined;
        createServiceNavigationElement(i);
    }
    setActiveService(newId);
});

ipcRenderer.on('deleteService', (e, id: number) => {
    removeServiceFeatures(id);

    if (selectedServiceId === id) {
        setActiveService(0);
    }

    services.splice(id, 1);
});

function createServiceNavigationElement(index: number, nextNavButton?: Element | null) {
    const service = services[index];
    if (!service) throw new Error('Service doesn\'t exist.');

    const li = document.createElement('li') as NavigationElement;
    service.li = li;

    const button = document.createElement('button');
    button.dataset.serviceId = '' + index;
    button.dataset.tooltip = service.name;
    button.addEventListener('click', () => {
        const rawId = button.dataset.serviceId;
        if (rawId) {
            const id = parseInt(rawId);
            setActiveService(id);
            ipcRenderer.send('setActiveService', id);
        }
    });
    button.addEventListener('contextmenu', e => {
        e.preventDefault();

        const service = services[index];
        if (!service) throw new Error('Service doesn\'t exist.');

        ipcRenderer.send(
            'open-service-navigation-context-menu',
            index,
            !!service.view && !!service.viewReady,
            !service.view && !service.viewReady,
            service.view?.getZoomFactor() !== 1 && service.view?.getZoomLevel() !== 0,
        );
    });

    let icon: HTMLImageElement | HTMLElement;
    if (service.useFavicon && service.favicon != null) {
        icon = document.createElement('img');
        if (icon instanceof HTMLImageElement) {
            icon.src = service.favicon;
            icon.alt = service.name;
        }
    } else if (service.isImage && service.icon) {
        icon = document.createElement('img');
        if (icon instanceof HTMLImageElement) {
            icon.src = service.icon;
            icon.alt = service.name;
        }
    } else {
        icon = document.createElement('i');
        let iconProperties = icons.find(i => `${i.set}/${i.name}` === service.icon);

        // Compatibility with old services
        if (!iconProperties) iconProperties = icons.find(i => i.name === service.icon);

        if (iconProperties) {
            iconProperties.faIcon.split(' ').forEach((cl: string) => {
                icon.classList.add(cl);
            });
        } else {
            icon.classList.add('fas', 'fa-circle');
        }
    }

    button.appendChild(icon);
    li.appendChild(button);
    li.button = button;

    const nav = document.querySelector('#service-selector');
    if (nav) {
        if (nextNavButton === nav || nextNavButton === undefined) {
            nav.appendChild(li);
        } else {
            nav.insertBefore(li, nextNavButton);
        }
    }

    if (service.autoLoad) {
        loadService(index, service);
    }

    initDrag(index, li);
}

let draggedId: number;
let lastDragTarget = -1;

function initDrag(index: number, li: NavigationElement) {
    li.serviceId = index;
    li.draggable = true;
    li.addEventListener('dragstart', (event: DragEvent) => {
        draggedId = index;
        if (event.dataTransfer) {
            event.dataTransfer.dropEffect = 'move';
        }
        lastDragPosition?.classList.remove('hidden');
    });
    li.addEventListener('dragover', (e: DragEvent) => {
        let realIndex = index;
        const rect = li.getBoundingClientRect();

        if ((e.clientY - rect.y) / rect.height >= 0.5) {
            realIndex++;
        }

        if (draggedId === realIndex - 1) {
            realIndex--;
        }

        resetDrag();
        const el = realIndex === services.length ?
            lastDragPosition :
            services[realIndex]?.li;
        lastDragTarget = realIndex;
        lastDragPosition?.classList.remove('hidden');

        if (el) {
            el.classList.add('drag-target');

            if (draggedId === realIndex || draggedId === realIndex - 1)
                el.classList.add('drag-target-self');
        }
    });
    li.addEventListener('dragend', () => {
        reorderService(draggedId, lastDragTarget);
        resetDrag();
    });
}

function resetDrag() {
    lastDragTarget = -1;
    serviceSelector?.querySelectorAll('li').forEach(li => {
        li.classList.remove('drag-target');
        li.classList.remove('drag-target-self');
    });
    const lastDragPosition = document.getElementById('service-last-drag-position');
    lastDragPosition?.classList.remove('drag-target');
    lastDragPosition?.classList.add('hidden');
}

function reorderService(serviceId: number, targetId: number) {
    console.log('Reordering service', serviceId, targetId);
    if (targetId >= 0) {
        oldActiveService = selectedServiceId;
        setActiveService(-1);
        ipcRenderer.send('reorderService', serviceId, targetId);
    }
}

document.addEventListener('DOMContentLoaded', () => {
    securityButton = document.getElementById('status');

    homeButton = document.getElementById('home');
    homeButton?.addEventListener('click', () => goHome());

    forwardButton = document.getElementById('forward');
    forwardButton?.addEventListener('click', () => goForward());

    backButton = document.getElementById('back');
    backButton?.addEventListener('click', () => goBack());

    refreshButton = document.getElementById('reload');
    refreshButton?.addEventListener('click', () => reload());

    addButton = document.getElementById('add-button');
    addButton?.addEventListener('click', () => ipcRenderer.send('create-new-service', null));

    settingsButton = document.getElementById('settings-button');
    settingsButton?.addEventListener('click', () => ipcRenderer.send('openSettings', null));
});

function setActiveService(serviceId: number) {
    const currentService = services[serviceId];
    process.nextTick(() => {
        if (currentService) {
            loadService(serviceId, currentService);
        }

        // Hide previous service
        if (typeof selectedServiceId === 'number') {
            const selectedService = services[selectedServiceId];
            if (selectedService && selectedService.view) {
                selectedService.view.classList.remove('active');
            }
        }

        // Show service
        currentService?.view?.classList.add('active');

        // Save active service ID
        selectedServiceId = serviceId;

        // Refresh navigation
        updateNavigation();
    });
}

function loadService(serviceId: number, service: FrontService) {
    // Load service if not loaded yet
    if (!service.view && !service.viewReady) {
        console.log('Loading service', serviceId);

        document.querySelector('#services > .loader')?.classList.remove('hidden');
        const view = service.view = document.createElement('webview');
        updateNavigation(); // Start loading animation
        view.setAttribute('enableRemoteModule', 'false');
        view.setAttribute('partition', 'persist:service_' + service.partition);
        view.setAttribute('autosize', 'true');
        view.setAttribute('allowpopups', 'true');
        if (specialPages) view.setAttribute('src', specialPages.empty);

        // Error handling
        view.addEventListener('did-fail-load', (e: DidFailLoadEvent) => {
            if (e.errorCode <= -100 && e.errorCode > -200) {
                if (specialPages) view.setAttribute('src', specialPages.connectionError);
            } else if (e.errorCode === -6) {
                if (specialPages) view.setAttribute('src', specialPages.fileNotFound);
            } else if (e.errorCode !== -3) {
                console.error('Unhandled error:', e);
            }
        });

        // Append element to DOM
        document.querySelector('#services')?.appendChild(view);

        // Load chain
        let listener: () => void;
        view.addEventListener('dom-ready', listener = () => {
            view.removeEventListener('dom-ready', listener);

            view.addEventListener('dom-ready', listener = () => {
                if (service.customCSS) {
                    view.insertCSS(service.customCSS)
                        .catch(console.error);
                }

                document.querySelector('#services > .loader')?.classList.add('hidden');
                service.li?.classList.add('loaded');
                service.viewReady = true;

                updateNavigation();

                if (selectedServiceId === null) {
                    setActiveService(serviceId);
                }
            });


            // Set custom user agent
            if (typeof service.customUserAgent === 'string') {
                ipcRenderer.send('set-web-contents-user-agent', view.getWebContentsId(), service.customUserAgent);
            }

            // Set context menu
            ipcRenderer.send('open-service-content-context-menu', view.getWebContentsId());

            // Set permission request handler
            ipcRenderer.send('set-partition-permissions', serviceId, view.partition);

            view.setAttribute('src', service.url);
        });

        // Load favicon
        view.addEventListener('page-favicon-updated', (event: PageFaviconUpdatedEvent) => {
            console.debug('Loaded favicons for', service.name, event.favicons);
            if (event.favicons.length > 0 && service.favicon !== event.favicons[0]) {
                ipcRenderer.send('setServiceFavicon', serviceId, event.favicons[0]);
                if (service.useFavicon) {
                    const img = document.createElement('img');
                    img.src = event.favicons[0];
                    img.alt = service.name;
                    img.onload = () => {
                        if (service.li) {
                            service.li.button.innerHTML = '';
                            service.li.button.appendChild(img);
                        }
                    };
                }
            }
        });

        // Display target urls
        view.addEventListener('update-target-url', (event: UpdateTargetUrlEvent) => {
            if (event.url.length === 0) {
                urlPreview?.classList.add('invisible');
            } else {
                urlPreview?.classList.remove('invisible');
                if (urlPreview) {
                    urlPreview.innerHTML = event.url;
                }
            }
        });
    }
}

function unloadService(serviceId: number) {
    const service = services[serviceId];
    if (!service) throw new Error('Service doesn\'t exist.');

    if (service.view && service.viewReady) {
        service.view.remove();
        service.view = undefined;
        service.li?.classList.remove('loaded');
        service.viewReady = false;

        if (selectedServiceId === serviceId) {
            selectedServiceId = null;

            for (let i = 0; i < services.length; i++) {
                const otherService = services[i];
                if (otherService && otherService.view && otherService.viewReady) {
                    setActiveService(i);
                    break;
                }
            }

            // false positive:
            // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
            if (selectedServiceId === null) {
                updateNavigation();
            }
        }
    }
}

function reloadService(serviceId: number) {
    const service = services[serviceId];
    if (!service) throw new Error('Service doesn\'t exist.');

    if (service.view && service.viewReady) {
        console.log('Reloading service', serviceId);
        document.querySelector('#services > .loader')?.classList.remove('hidden');
        service.view.reload();
    } else if (!service.view && !service.viewReady) {
        loadService(serviceId, service);
    }
}

function updateNavigation() {
    console.debug('Updating navigation');
    // Update active list element
    for (let i = 0; i < services.length; i++) {
        const service = services[i];
        if (!service) continue;

        if (!service.li) continue;

        // Active?
        if (selectedServiceId === i) service.li.classList.add('active');
        else service.li.classList.remove('active');

        // Loading?
        if (service.view && !service.viewReady) service.li.classList.add('loading');
        else service.li.classList.remove('loading');

        // Loaded?
        if (service.viewReady) service.li.classList.add('loaded');
        else service.li.classList.remove('loaded');
    }

    if (selectedServiceId !== null && services[selectedServiceId]?.viewReady) {
        console.debug('Updating navigation buttons because view is ready');
        // Update history navigation
        const view = services[selectedServiceId]?.view;

        homeButton?.classList.remove('disabled');

        if (view && view.canGoForward()) forwardButton?.classList.remove('disabled');
        else forwardButton?.classList.add('disabled');

        if (view && view.canGoBack()) backButton?.classList.remove('disabled');
        else backButton?.classList.add('disabled');

        refreshButton?.classList.remove('disabled');

        updateStatusButton();
    }

    updateWindowTitle();
}

function updateStatusButton() {
    if (typeof selectedServiceId !== 'number') return;

    const protocol = services[selectedServiceId]?.view?.getURL().split('://')[0] || 'unknown';
    securityButton?.childNodes.forEach(el => {
        if (el instanceof HTMLElement) {
            if (el.classList.contains(protocol)) el.classList.add('active');
            else el.classList.remove('active');
        }
    });
}

function updateWindowTitle() {
    if (selectedServiceId === null) {
        ipcRenderer.send('update-window-title', null);
    } else {
        const service = services[selectedServiceId];
        if (service?.viewReady && service.view) {
            ipcRenderer.send('update-window-title', selectedServiceId, service.view.getWebContentsId());
        }
    }
}

function goHome() {
    if (selectedServiceId === null) return;

    const service = services[selectedServiceId];
    if (!service) throw new Error('Service doesn\'t exist.');

    service.view?.loadURL(service.url)
        .catch(console.error);
}

function goForward() {
    if (selectedServiceId === null) return;

    const view = services[selectedServiceId]?.view;
    if (view) ipcRenderer.send('go-forward', view.getWebContentsId());
}

function goBack() {
    if (selectedServiceId === null) return;

    const view = services[selectedServiceId]?.view;
    if (view) ipcRenderer.send('go-back', view.getWebContentsId());
}

function reload() {
    if (selectedServiceId === null) return;

    reloadService(selectedServiceId);
}

ipcRenderer.on('fullscreenchange', (e, fullscreen: boolean) => {
    if (fullscreen) document.body.classList.add('fullscreen');
    else document.body.classList.remove('fullscreen');
});

type FrontService = Service & {
    view?: Electron.WebviewTag;
    viewReady?: boolean;
    li?: NavigationElement;
};

type NavigationElement = HTMLLIElement & {
    serviceId: number;
    button: HTMLButtonElement;
};