import { LitElement, html, css } from 'lit';
import { property, queryAll } from 'lit/decorators.js';
import { CloudIcon, HomeIcon, LoginIcon, LinkIcon, MenuIcon, UserCircleIcon, LogoutIcon } from './icons'
import { EVENT_MENU_ITEM_SELECTED, EVENT_MENU_ITEM_UNSELECTED, MenuItem } from './menu-item';
import { MenuSubItem } from './menu-sub-item';

interface Manifest {
    id: string
    description: string
    metadata: { [key: string]: any }
    tags: string[]
    title: string
    version: string
    url?: string
}

interface Profile {
    sub?: string
    preferred_username?: string
    iss?: string
    edge_role?: string
    edge_tenant?: string
    edge_entrypoint?: string
}

const BASE_API_URL = '/edge/api/v1';

enum Roles {
    visitor = 0,
    user = 1,
    superuser = 2,
    admin = 3,
    superadmin = 4
}

export class Menu extends LitElement {
    @property({ attribute: 'app-icon-url', type: String })
    appIconUrl: string;

    @property({ attribute: 'app-title', type: String })
    appTitle: string;

    @property({ attribute: 'hidden', type: Boolean })
    hidden: boolean;

    @property()
    _apps: Manifest[] = []

    @property()
    _profile: Profile

    static styles = css`
    :host {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        height: 60px;
        background-color: #fff;
        display: flex;
        flex-direction: row;
        align-items: center;
        justify-content: center;
        z-index: 9999;
    }

    :host([hidden]) {
        display: none;
    }
    `;

    @queryAll('edge-menu-item')
    _menuItems: NodeListOf<MenuItem>

    constructor() {
        super();
        this.addEventListener(EVENT_MENU_ITEM_SELECTED, this._handleMenuItemSelected.bind(this));
        this.addEventListener(EVENT_MENU_ITEM_UNSELECTED, this._handleMenuItemUnselected.bind(this));
        
        this._fetchApps();
        this._fetchProfile();
    }

    render() {
        const apps = this._renderApps()

        return html`
            <edge-menu-item name='menu' label="${ this.appTitle || "App" }" icon-url='${ this.appIconUrl || MenuIcon }'>
                <edge-menu-sub-item name='home' label='Home' icon-url='${HomeIcon}' link-url='/'></edge-menu-sub-item>
                <slot></slot>
            </edge-menu-item>
            ${ this._renderApps() }
            ${ this._renderProfile() }
        `;
    }

    _fetchApps() {
        return fetch(`${BASE_API_URL}/apps`)
            .then(res => res.json())
            .then(result => {
                if (result.error) {
                    throw new Error(`Unexpected server error: ${result.error.code}`);
                }

                return result.data?.manifests || [];
            })
            .then((manifests: Manifest[]) => {
                const promises = manifests.map((m: Manifest) => {
                    const fetchOptions: RequestInit = {
                        method: 'POST', 
                        body: JSON.stringify({}),
                        headers: {
                            'Content-Type': 'application/json',
                        }
                    };
                    return fetch(`${BASE_API_URL}/apps/${m.id}/url`, fetchOptions)
                        .then(res => res.json())
                        .then(result => {
                            if (result.error) {
                                throw new Error(`Unexpected server error: ${result.error.code}`);
                            }

                            m.url = result.data?.url;

                            return m;
                        })
                    ;
                });

                return Promise.all(promises);
            })
            .then((manifests: Manifest[]) => {
                this._apps = manifests;
            })
            .catch(err => console.error(err))
    }

    _fetchProfile() {
        return fetch(`${BASE_API_URL}/profile`)
            .then(res => res.json())
            .then(result => {
                if (result.error) {
                    switch (result.error.code) {
                        case "unauthorized":
                            return null;
                        default:
                            throw new Error(`Unexpected server error: ${result.error.code}`);
                    }
                }

                return result.data?.profile;
            })
            .then(profile => {
                this._profile = profile;
            })
            .catch(err => console.error(err))
        ;
    }

    _renderApps() {
        const apps = this._apps
            .filter(manifest => this._canAccess(manifest))
            .map(manifest => {
                const iconUrl = ( ( manifest.url || '') + ( manifest.metadata?.paths?.icon || '' ) ) || LinkIcon;
                return html`
                    <edge-menu-sub-item 
                        name='${ manifest.id }' 
                        label='${ manifest.title }' 
                        icon-url='${ iconUrl }' 
                        link-url='${ manifest.url || '#' }'>
                    </edge-menu-sub-item>
                `
            });

        return html`
            <edge-menu-item name='apps' label='Apps' icon-url='${CloudIcon}'>
                ${ apps }
            </edge-menu-item>
        `;
    }

    _canAccess(manifest: Manifest): boolean {
        const currentRole = this._profile?.edge_role || 'visitor';
        const minimumRole = manifest.metadata?.minimumRole || 'visitor';

        return Roles[currentRole] >= Roles[minimumRole];
    }

    _renderProfile() {
        const profile = this._profile;
        return html`
            <edge-menu-item name='profile' label="${profile?.preferred_username || 'Profile'}" icon-url='${UserCircleIcon}'>
                ${
                    profile && profile.iss != "anon" ?
                    html`<edge-menu-sub-item name='login' label='Logout' icon-url='${LogoutIcon}' link-url='/edge/auth/logout'></edge-menu-sub-item>` :
                    html`<edge-menu-sub-item name='login' label='Login' icon-url='${LoginIcon}' link-url='/edge/auth/login'></edge-menu-sub-item>`
                }
            </edge-menu-item>
        `;
    }

    _handleMenuItemSelected(evt: CustomEvent) {
        const selectedMenuItem: HTMLElement = evt.detail.element;

        selectedMenuItem.classList.add('selected');
        selectedMenuItem.classList.remove('unselected');

        for (let item, i = 0; (item = this._menuItems[i]); i++) {
            if (item === selectedMenuItem) continue;
            
            item.unselect();
            item.classList.add('unselected');
        }
    }

    _handleMenuItemUnselected(evt: CustomEvent) {
        const unselectedMenuItem: HTMLElement = evt.detail.element;

        unselectedMenuItem.classList.remove('selected');

        const hasSelectedItem = this.renderRoot.querySelectorAll('edge-menu-item.selected').length !== 0

        if (hasSelectedItem) {
            return
        }

        for (let item, i = 0; (item = this._menuItems[i]); i++) {
            item.classList.remove('unselected');
        }
    }
}

declare global {
    interface HTMLElementTagNameMap {
        "edge-menu": Menu;
        "edge-menu-item": MenuItem;
        "edge-menu-sub-item": MenuSubItem;
    }
}