const Model = require("flitter-orm/src/model/Model");
const { ObjectId } = require("mongodb");
const uuid = require('uuid/v4');

const ActiveScope = require('../scopes/Active.scope')

/*
 * Page Model
 * -------------------------------------------------------------
 * Put some description here!
 */
class Page extends Model {
	static get services() {
		return [...super.services, "models"];
	}
	static get schema() {
		// Return a flitter-orm schema here.
		return {
			UUID: {type: String, default: () => uuid()},
			Name: String,
			OrgUserId: ObjectId,
			IsPublic: {type: Boolean, default: true},
			IsVisibleInMenu: {type: Boolean, default: true},
			ParentId: String,
			NodeIds: [String],
			CreatedAt: {type: Date, default: () => new Date},
			UpdatedAt: {type: Date, default: () => new Date},
			DeletedAt: Date,
			Active: {type: Boolean, default: true},
			CreatedUserId: {type: String},
			UpdateUserId: {type: String},
			ChildPageIds: [String],

			// Menu flags
			noDelete: { type: Boolean, default: false },
			virtual: { type: Boolean, default: false },

			// Sharing properties
			shared_users_view: [ObjectId],
			shared_users_update: [ObjectId],
			shared_users_manage: [ObjectId],
		};
	}

	static scopes = [new ActiveScope]

	is_shared() {
		return this.shared_users_view.length > 0 || this.shared_users_update.length > 0 || this.shared_users_manage.length > 0
	}

	// ================= RELATIONSHIPS =================
	get user() {
		const User = this.models.get("auth:User")
		return this.belongs_to_one(User, "OrgUserId", "_id")
	}

	get nodes() {
		const Node = this.models.get("api:Node")
		return this.has_many(Node, "NodeIds", "UUID")
	}
	get childPages() {
		const Page = this.models.get("api:Page")
		return this.has_many(Page, "ChildPageIds", "UUID")
	}

	get parent() {
		const Parent = this.models.get("api:Page")
		return this.belongs_to_one(Parent, "ParentId", "UUID")
	}

	get view_users() {
		const User = this.models.get('auth:User')
		return this.has_many(User, 'shared_users_view', '_id')
	}

	get update_users() {
		const User = this.models.get('auth:User')
		return this.has_many(User, 'shared_users_update', '_id')
	}

	get manage_users() {
		const User = this.models.get('auth:User')
		return this.has_many(User, 'shared_users_manage', '_id')
	}

	// ================= SECURITY =================
	accessible_by(user, mode = 'view') {
		const base_access = user.can(`page:${this.UUID}:${mode}`)
	}

	async is_accessible_by(user, mode = 'view') {
		const can_manage = user.can(`page:${this.UUID}:manage`)
		const can_update = user.can(`page:${this.UUID}:update`)
		const can_view = user.can(`page:${this.UUID}:view`)
		const can_all = user.can(`page:${this.UUID}`)

		// Allow universal access
		if ( can_all ) return true
		// deny if blocked
		else if ( user.can(`page:${this.UUID}:block`) ) return false
		// manage, update, view can view
		else if ( mode === 'view' && (can_manage || can_update || can_view) ) return true
		// manage, update can update
		else if ( mode === 'update' ) {
			if ( can_manage || can_update ) return true
			// If other permissions are explicitly set for this page, use those
			else if ( can_view ) return false
		}
		// manage can manage
		else if ( mode === 'manage' ) {
			if ( can_manage ) return true
			// If other permissions are explicitly set for this page, use those
			else if ( can_update || can_view ) return false
		}

		// allow universal access
		// deny blocked users

		// If there are no explicit permissions set for this node, check the parent
		const parent = await this.parent
		if ( parent ) return (await this.parent).is_accessible_by(user, mode)
		else return false
	}

	async access_level_for(user) {
		if ( await this.is_accessible_by(user, 'manage') ) return 'manage'
		else if ( await this.is_accessible_by(user, 'update') ) return 'update'
		else if ( await this.is_accessible_by(user, 'view') ) return 'view'
		else return false
	}

	async share_with(user, level = 'view') {
		if ( !['view', 'update', 'manage'].includes(level) ) {
			throw new Error(`Invalid share level: ${level}`)
		}

		// Remove existing sharing info
		await this.unshare_with(user)

		// Add the page to the user's permissions:
		user.allow(`page:${this.UUID}:${level}`)

		// Add the user to the appropriate access list
		this[`shared_users_${level}`].push(user._id)

		await this.save()
		await user.save()
	}

	async unshare_with(user) {
		// Remove this page from the user's permissions
		if ( user.can(`page:${this.UUID}`) ) user.disallow(`page:${this.UUID}`)
		for ( const level of ['view', 'update', 'manage'] ) {
			if ( user.can(`page:${this.UUID}:${level}`) ) user.disallow(`page:${this.UUID}:${level}`)
		}

		// Remove the user from this page's access lists
		this.shared_users_view = this.shared_users_view.filter(x => String(x) !== user.id)
		this.shared_users_update = this.shared_users_update.filter(x => String(x) !== user.id)
		this.shared_users_manage = this.shared_users_manage.filter(x => String(x) !== user.id)

		await this.save()
		await user.save()
	}

}

module.exports = exports = Page;