Register formula dependencies and listen for chnge

Author: Vic van Cooten

src/appbox-formulas/Functions/and.ts

@@ -0,0 +1,30 @@
+import Formula from "../index";
+
+/*
+ * AND(...arg1, etc)
+ * returns true if ALL children are true
+ */
+
+export default {
+  execute: (fArguments, data, formula: Formula) =>
+    new Promise(async (resolve, reject) => {
+      let isTrue = true;
+      for (let x = 0; x < fArguments.length; x++) {
+        if (fArguments[x] !== true) isTrue = false;
+      }
+
+      resolve(isTrue);
+    }),
+  onCompile: (fArguments) => {
+    const deps = [];
+
+    // For each argument, check if their type is string (so not a "string", but a string). If so, it refers to a field and is a dependency.
+    for (let x = 0; x < fArguments.length; x++) {
+      if (typeof fArguments[x] === "string") deps.push(fArguments[x]);
+    }
+
+    return deps;
+  },
+  // Give a sample result so it's parent functions know what we will return on execute and can perform the right precompiling.
+  returnPreview: true,
+};

src/appbox-formulas/Functions/index.ts

@@ -0,0 +1,7 @@
+import and from "./and";
+
+const functions = {
+  and,
+};
+
+export default functions;

src/appbox-formulas/Types.ts

@@ -0,0 +1,93 @@
+import { Collection } from "mongodb";
+
+/* Server technical types */
+export interface DBCollectionsType {
+  models: Collection;
+  objects: Collection;
+  usersettings: Collection;
+}
+
+/* Model */
+export interface ModelType {
+  _id: string;
+  key: string;
+  key_plural: string;
+  label: string;
+  label_plural: string;
+  app: string;
+  primary: string;
+  icon: string;
+  locked?: boolean;
+  fields: { [key: string]: ModelFieldType };
+  layouts: { [key: string]: ModelLayoutType };
+  lists: { [key: string]: ModelListType };
+  permissions: {
+    create: string[];
+    read: string[];
+    read_own: string[];
+    update: string[];
+    update_own: string[];
+    delete: string[];
+    delete_own: string[];
+  };
+}
+
+// Field
+export interface ModelFieldType {
+  label: string;
+  type?: "text" | "number" | "relationship" | "formula" | "options";
+  required?: boolean;
+  unique?: boolean;
+  // Options
+  selectMultiple?: boolean;
+  optionsDisplayAs?: "dropdown" | "list" | string;
+  options?: { label: string; value: string }[];
+  // Relationship
+  relationshipTo?: string;
+  // Formula
+  formula?: string;
+}
+
+// Layout
+export interface ModelLayoutType {
+  label: string;
+  layout: LayoutItemType[];
+}
+export interface LayoutItemType {
+  key?: string;
+  label: string;
+  type: string;
+  items?: LayoutItemType[];
+  args?: { [key: string]: any };
+}
+
+// List
+export interface ModelListType {
+  label?: string;
+  filter?: {};
+  fields?: string[];
+}
+
+/* Object types */
+export interface ObjectType {
+  _id: string;
+  meta: {
+    model: string;
+    createdOn: Date;
+    lastModifiedOn: Date;
+    createdBy: string;
+    lastModifiedBy: string;
+    owner: string;
+    team?: string;
+  };
+  [key: string]: any;
+}
+
+export interface UserObjectType extends ObjectType {
+  username: string;
+  first_name: string;
+  last_name: string;
+  email: string;
+  password: string;
+  roles: string[];
+}

src/appbox-formulas/index.ts

@@ -1,17 +1,39 @@
+import { ModelType } from "./Types";
+import { find } from "lodash";
+import uniqid from "uniqid";
 const uniqid = require("uniqid");
-
+/*
+ * The Formula class
+ */
 class Formula {
+  id = uniqid();
+  // Label
+  label;
   // Original formula string
   formulaString;
   // Holds formula template (tags replaced by unique identifiers)
   formulaTemplate;
   // Array holding all tags
   tags: { tag: string; identifier: string }[] = [];
+  // Array holding all dependencies
+  dependencies: { field: string; model: string; localDependency?: true }[] = [];
+  // Hold all models
+  models: ModelType[];
+  // Promise to check if constructor is done working asynchronously
+  onParsed: Promise<void>;
 
   // Constructor
-  constructor(formula, mode: "{{" | "[[" = "{{") {
+  constructor(
+    formula,
+    startingModelKey: string,
+    label?: string,
+    mode: "{{" | "[[" = "{{", // This is for nested formulas, such as templates
+    models?: ModelType[] // Some data may be statically delivered in JSON format. Then we don't need this. If we have dynamic (field__r) data we need to query the database and parse the correct dependencies.
+  ) {
     this.formulaString = formula;
     this.formulaTemplate = formula;
+    this.models = models;
+    this.label = label;
 
     // Pre-parse tags
     const tagPattern =
@@ -27,9 +49,100 @@ class Formula {
       );
     });
 
-    // Loop through all the tags
-    console.log(this.formulaString, this.formulaTemplate, this.tags);
+    // Parse dependencies
+    this.onParsed = new Promise((resolve, reject) =>
+      this.parseDependencies(startingModelKey).then(
+        () => resolve(),
+        (reason) =>
+          reject(`(${label}) couldn't process dependencies: ${reason}`)
+      )
+    );
   }
+
+  // Parse dependencies for all tags (asynchronously used in )
+  parseDependencies = (startModelKey: string) =>
+    new Promise<void>(async (resolve, reject) => {
+      //@ts-ignore
+      await this.tags.reduce(async (prevTag, tag) => {
+        await prevTag;
+
+        const tagParts = tag.tag.split(/[-+*\/](?![^\(]*\))/gm);
+        //@ts-ignore
+        await tagParts.reduce(async (prevTagPart, tagPart) => {
+          // The regexp splits on -, but not within parenthesis
+          const part = tagPart.trim();
+
+          // Check the context of the tag part and perform the appropriate action
+          if (part.match(/\w*\(.+\)/)) {
+            // This part has a function call. We need to preprocess these functions to figure out what the dependencies are.
+            const func = new RegExp(/(?<fName>\w*)\((?<fArgs>.*)\)/gm).exec(
+              part
+            );
+            console.log("Preprocessing", func.groups.fName, func.groups.fArgs);
+          } else if (part.match(/\./)) {
+            if (part.match("__r")) {
+              // This is an object based relationship. Resolve the dependencies
+              if (this.models) {
+                // We're going to split by . and resolve them all to set a dependency.
+                const tagParts = part.split(".");
+                let currentModelKey = startModelKey;
+                //@ts-ignore
+                await tagParts.reduce(async (prevPart, currPart) => {
+                  await prevPart;
+
+                  if (currPart.match("__r")) {
+                    const fieldName = currPart.replace("__r", "");
+
+                    // This is a part of the relationship. It needs to be registered as dependency, in case it's value changes.
+                    this.dependencies.push({
+                      model: currentModelKey,
+                      field: fieldName,
+                      ...(currentModelKey === startModelKey
+                        ? { localDependency: true }
+                        : {}),
+                    });
+                    // It also needs to be parsed to figure out what model the next
+                    const currentModel = find(
+                      this.models,
+                      (o) => o.key === currentModelKey
+                    );
+                    const field = currentModel.fields[fieldName];
+                    currentModelKey = field.relationshipTo;
+                  } else {
+                    this.dependencies.push({
+                      model: currentModelKey,
+                      field: currPart,
+                    });
+                  }
+
+                  return currPart;
+                }, tagParts[0]);
+                resolve();
+              } else {
+                reject("no-models-provided");
+              }
+            } else {
+              // This is a regular dependency (a.b.c), so we can just add it as a field
+              this.dependencies.push({
+                field: part,
+                model: startModelKey,
+                localDependency: true,
+              });
+            }
+          } else {
+            this.dependencies.push({
+              field: part,
+              model: startModelKey,
+              localDependency: true,
+            });
+          }
+        }, tagParts[0]);
+
+        return tag;
+      }, this.tags[0]);
+
+      resolve();
+    });
 }
 
 export default Formula;

src/engine.ts

@@ -14,6 +14,10 @@ class Engine {
     objects: null,
     usersettings: null,
   };
+  // All models
+  models: ModelType[];
+  // Update triggers
+  updateTriggers: { [key: string]: string } = {};
 
   // Initialise
   constructor(db) {
@@ -23,19 +27,46 @@ class Engine {
       objects: db.collection("objects"),
       usersettings: db.collection("usersettings"),
     };
+    this.collections.models
+      .find({})
+      .toArray()
+      .then((models: ModelType[]) => (this.models = models));
     console.log("Engine booting up");
   }
 
   // Parse formulas
-  parseFormulas() {
+  async parseFormulas() {
     console.log("Parsing formulas");
-    this.collections.models.find({}).forEach((model: ModelType) => {
+    const models = await this.collections.models.find({}).toArray();
+    await models.reduce(async (prevModel, model) => {
+      await prevModel;
+
       map(model.fields, (field, key) => {
         if (field.type === "formula") {
-          console.log(`🧪 Parsing formula ${field.label}.`);
-          const formula = new Formula(field.formula);
+          console.log(`🧪 Parsing formula '${field.label}'.`);
+          const formula = new Formula(
+            field.formula,
+            model.key,
+            `🧪 ${field.label}`,
+            "{{",
+            this.models
+          );
+          formula.onParsed.then(() => {
+            formula.dependencies.map((dep) => {
+              this.updateTriggers[`${dep.model}___${dep.field}`] = formula.id;
+            });
+          });
         }
       });
+      return model;
+    }, models[0]);
+    console.log("🥼 Done parsing formulas");
+    this.registerOnObjectChangeListeners();
+  }
+
+  registerOnObjectChangeListeners() {
+    this.collections.objects.watch().on("change", async (change) => {
+      console.log(change);
     });
   }
 }