From 6f185372b348aae1b1093c960e904ac41d49fc96 Mon Sep 17 00:00:00 2001
From: Bhanu Agrawal <bhanu.agrawal@dechea.com>
Date: Fri, 14 Oct 2022 17:31:18 +0530
Subject: [PATCH] Added graphql to fql converter

---
 .gitignore               |   1 +
 graphqlToFQLConverter.js | 113 +++++++++++++++++++++++++++++++++++++++
 package-lock.json        |  31 +++++++++++
 package.json             |  23 ++++++++
 4 files changed, 168 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 graphqlToFQLConverter.js
 create mode 100644 package-lock.json
 create mode 100644 package.json

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b512c09
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+node_modules
\ No newline at end of file
diff --git a/graphqlToFQLConverter.js b/graphqlToFQLConverter.js
new file mode 100644
index 0000000..47c7f88
--- /dev/null
+++ b/graphqlToFQLConverter.js
@@ -0,0 +1,113 @@
+const { parse } = require('graphql/language/parser');
+
+const capitalizeFirstLetter = (string) => {
+  return string.charAt(0).toUpperCase() + string.slice(1);
+}
+
+const composeOperator = (stringArray) => {
+  let result = stringArray[1];
+  for (let index = 2; index < stringArray.length; index++) {
+    result += capitalizeFirstLetter(stringArray[index]);
+  }
+  return result;
+}
+
+const getCollectionSortCriteria = (arg) => {
+  const [key, direction] = arg.value.value.split('_');
+  return `order(${direction.toLowerCase()}(.${key}))`;
+}
+
+const buildCriteriaString = (fields) => {
+  let criteriaString = '';
+  for (let index = 0; index < fields.length; index++) {
+    const splittedString = fields[index].name.value.split("_");
+    const key = splittedString[0];
+    const operator = composeOperator(splittedString);
+    const value = fields[index].value.value;
+
+    criteriaString += `.${key}.${operator}("${value}")`;
+    criteriaString += index < fields.length - 1 ? ' && ' : '';
+  }
+  return criteriaString;
+}
+
+const getCollectionFilterCriteria = (arg) => {
+  const { fields } = arg.value;
+  const criteriaString = buildCriteriaString(fields);
+  return `firstWhere(${criteriaString})`;
+}
+
+const getCollectionLevelCriteria = (args) => {
+  let sortCriteria = null;
+  let filterCriteria = null;
+  for (const arg of args) {
+    const keyword = arg.name.value;
+    if (keyword === 'orderBy') {
+      sortCriteria = getCollectionSortCriteria(arg);
+    }
+    else if (keyword === 'where') {
+      filterCriteria = getCollectionFilterCriteria(arg);
+    }
+  }
+  return { sortCriteria, filterCriteria };
+}
+
+const buildArrayExpression = (name, args) => {
+  const { fields } = args[0].value;
+  const criteriaString = buildCriteriaString(fields);
+  return `${name}.filter(${criteriaString}).at(0)`;
+}
+
+const getLastExpression = (input, result) => {
+  if (!input) return result;
+  result += '.';
+  const selections = input.selections[0];
+  const name = selections?.name?.value;
+  const args = selections?.arguments;
+  if (!args || args.length == 0) {
+    result += name;
+  }
+  else {
+    result += buildArrayExpression(name, args);
+  }
+  return getLastExpression(selections.selectionSet, result);
+}
+
+// TRP_TreatmentPlans.all.order(asc(.name)).firstWhere(.name.startsWith("Jamie"))
+//.treatments.filter(.title.startsWith("Union")).at(0).selectedItems
+
+const query = `
+query MyQuery {
+    TRP_TreatmentPlans(orderBy: name_ASC, where: {name_starts_with: "Jamie"}) {
+      treatments(where: {title_starts_with: "Union"}) {
+        selectedItems {
+          quantity {
+            items
+          }
+        }
+      }
+    }
+  }   
+`;
+
+const convertGraphQLToFQL = (query) => {
+  let fqlString = '';
+  const parsedQuery = parse(query);
+  const selections = parsedQuery.definitions[0].selectionSet.selections[0];
+  const collectionName = selections.name.value;
+  const args = selections.arguments;
+
+  fqlString += `${collectionName}.all`;
+  const { sortCriteria, filterCriteria } = getCollectionLevelCriteria(args);
+
+  fqlString += sortCriteria ? `.${sortCriteria}` : '';
+  fqlString += filterCriteria ? `.${filterCriteria}` : '';
+
+  const input = selections.selectionSet;
+  const lastExpression = getLastExpression(input, '');
+  fqlString += lastExpression;
+
+  return fqlString;
+};
+
+console.log(convertGraphQLToFQL(query));
\ No newline at end of file
diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..704a4eb
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,31 @@
+{
+  "name": "rules-engine",
+  "version": "1.0.0",
+  "lockfileVersion": 2,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "rules-engine",
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "graphql": "^16.6.0"
+      }
+    },
+    "node_modules/graphql": {
+      "version": "16.6.0",
+      "resolved": "https://registry.npmjs.org/graphql/-/graphql-16.6.0.tgz",
+      "integrity": "sha512-KPIBPDlW7NxrbT/eh4qPXz5FiFdL5UbaA0XUNz2Rp3Z3hqBSkbj0GVjwFDztsWVauZUWsbKHgMg++sk8UX0bkw==",
+      "engines": {
+        "node": "^12.22.0 || ^14.16.0 || ^16.0.0 || >=17.0.0"
+      }
+    }
+  },
+  "dependencies": {
+    "graphql": {
+      "version": "16.6.0",
+      "resolved": "https://registry.npmjs.org/graphql/-/graphql-16.6.0.tgz",
+      "integrity": "sha512-KPIBPDlW7NxrbT/eh4qPXz5FiFdL5UbaA0XUNz2Rp3Z3hqBSkbj0GVjwFDztsWVauZUWsbKHgMg++sk8UX0bkw=="
+    }
+  }
+}
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..435a72e
--- /dev/null
+++ b/package.json
@@ -0,0 +1,23 @@
+{
+  "name": "rules-engine",
+  "version": "1.0.0",
+  "description": "",
+  "main": "composer.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/Dechea/rules-engine.git"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/Dechea/rules-engine/issues"
+  },
+  "homepage": "https://github.com/Dechea/rules-engine#readme",
+  "dependencies": {
+    "graphql": "^16.6.0"
+  }
+}