const Observable = require('./utils/observable');

module.exports = {
    async init() {
        if (this._initialized) return;
        this.initConfig();
        this.initGlobals();
        this.docs = new Observable();
        this._initialized = true;
    },

    initConfig() {
        this.config = {
            serverURL: '',
            backend: 'sqlite',
            port: 8000
        };
    },

    initGlobals() {
        this.metaCache = {};
        this.models = {};
        this.forms = {};
        this.views = {};
        this.flags = {};
        this.methods = {};
        // temp params while calling routes
        this.params = {};
    },

    registerLibs(common) {
        // add standard libs and utils to frappe
        common.initLibs(this);
    },

    registerModels(models, type) {
        // register models from app/models/index.js
        const toAdd = Object.assign({}, models.models);

        // post process based on type
        if (models[type]) {
            models[type](toAdd);
        }

        Object.assign(this.models, toAdd);
    },

    registerView(view, name, module) {
        if (!this.views[view]) this.views[view] = {};
        this.views[view][name] = module;
    },

    registerMethod({method, handler}) {
        this.methods[method] = handler;
        if (this.app) {
            // add to router if client-server
            this.app.post(`/api/method/${method}`, this.asyncHandler(async function(request, response) {
                const data = await handler(request.body);
                response.json(data);
            }));
        }
    },

    async call({method, args}) {
        if (this.isServer) {
            if (this.methods[method]) {
                return await this.methods[method](args);
            } else {
                throw `${method} not found`;
            }
        }

        let url = `/api/method/${method}`;
        let response = await fetch(url, {
            method: 'POST',
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json'
            },
            body: JSON.stringify(args || {})
        });
        return await response.json();
    },

    addToCache(doc) {
        if (!this.docs) return;

        // add to `docs` cache
        if (doc.doctype && doc.name) {
            if (!this.docs[doc.doctype]) {
                this.docs[doc.doctype] = {};
            }
            this.docs[doc.doctype][doc.name] = doc;

            // singles available as first level objects too
            if (doc.doctype === doc.name) {
                this[doc.name] = doc;
            }

            // propogate change to `docs`
            doc.on('change', params => {
                this.docs.trigger('change', params);
            });
        }
    },

    isDirty(doctype, name) {
        return (this.docs && this.docs[doctype] && this.docs[doctype][name]
            && this.docs[doctype][name]._dirty) || false;
    },

    getDocFromCache(doctype, name) {
        if (this.docs && this.docs[doctype] && this.docs[doctype][name]) {
            return this.docs[doctype][name];
        }
    },

    getMeta(doctype) {
        if (!this.metaCache[doctype]) {
            let model = this.models[doctype];
            if (!model) {
                throw `${doctype} is not a registered doctype`;
            }
            let metaClass = model.metaClass || this.BaseMeta;
            this.metaCache[doctype] = new metaClass(model);
        }

        return this.metaCache[doctype];
    },

    async getDoc(doctype, name) {
        let doc = this.getDocFromCache(doctype, name);
        if (!doc) {
            doc = new (this.getDocumentClass(doctype))({doctype:doctype, name: name});
            await doc.load();
            this.addToCache(doc);
        }
        return doc;
    },

    getDocumentClass(doctype) {
        const meta = this.getMeta(doctype);
        return meta.documentClass || this.BaseDocument;
    },

    async getSingle(doctype) {
        return await this.getDoc(doctype, doctype);
    },

    async getDuplicate(doc) {
        const newDoc = await this.getNewDoc(doc.doctype);
        for (let field of this.getMeta(doc.doctype).getValidFields()) {
            if (['name', 'submitted'].includes(field.fieldname)) continue;
            if (field.fieldtype === 'Table') {
                newDoc[field.fieldname] = (doc[field.fieldname] || []).map(d => {
                    let newd = Object.assign({}, d);
                    newd.name = '';
                    return newd;
                });
            } else {
                newDoc[field.fieldname] = doc[field.fieldname];
            }
        }
        return newDoc;
    },

    async getNewDoc(doctype) {
        let doc = this.newDoc({doctype: doctype});
        doc._notInserted = true;
        doc.name = this.getRandomString();
        this.addToCache(doc);
        return doc;
    },

    newDoc(data) {
        let doc = new (this.getDocumentClass(data.doctype))(data);
        doc.setDefaults();
        return doc;
    },

    async insert(data) {
        return await (this.newDoc(data)).insert();
    },

    async syncDoc(data) {
        let doc;
        if (await this.db.exists(data.doctype, data.name)) {
            doc = await this.getDoc(data.doctype, data.name);
            Object.assign(doc, data);
            await doc.update();
        } else {
            doc = this.newDoc(data);
            await doc.insert();
        }
    },

    // only for client side
    async login(email, password) {
        if (email === 'Administrator') {
            this.session = {
                user: 'Administrator'
            }
            return;
        }

        let response = await fetch(this.getServerURL() + '/api/login', {
            method: 'POST',
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({ email, password })
        });

        if (response.status === 200) {
            const res = await response.json();

            this.session = {
                user: email,
                token: res.token
            }

            return res;
        }

        return response;
    },

    async signup(email, fullName, password) {
        let response = await fetch(this.getServerURL() + '/api/signup', {
            method: 'POST',
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({ email, fullName, password })
        });

        if (response.status === 200) {
            return await response.json();
        }

        return response;
    },

    getServerURL() {
        return this.config.serverURL || '';
    },

    close() {
        this.db.close();

        if (this.server) {
            this.server.close();
        }
    }
};