1 files changed, 80 insertions, 0 deletions
diff --git a/src/context.ts b/src/context.ts
new file mode 100644
index 0000000..35fa1ae
--- /dev/null
+++ b/src/context.ts
@@ -0,0 +1,80 @@
+import { Project, ScriptTarget, Type, Node, SyntaxKind } from 'ts-morph'
+import path from 'path'
+import { v4 as uuid } from 'uuid';
+import { Ctx } from './types';
+
+const RESULT_TYPE_NAME = '__$result'
+
+export const createContext = (): Ctx => {
+  const project = new Project({
+    compilerOptions: {
+      target: ScriptTarget.ES3,
+    },
+  })
+
+  const typeChecker = project.getTypeChecker()
+
+  const [filePath] = process.argv.slice(2)
+
+  if (!filePath) {
+    throw new Error('Must specify ts file to run')
+  }
+
+  const sourceFile = project.addSourceFileAtPath(path.resolve(filePath))
+
+  const entryPoint = sourceFile.getExportedDeclarations().get('main')?.[0]
+
+  if (!entryPoint) {
+    throw new Error('No "main" entrypoint defined in source file')
+  }
+
+  const typeToString = (ty: Type | undefined): string =>
+    ty ? typeChecker.compilerObject.typeToString(ty.compilerType) : ''
+
+  const [resultTypeNode] = sourceFile.addStatements(`type ${RESULT_TYPE_NAME} = {}`)
+
+  const getResultExpr = (resultKey?: string) => `${RESULT_TYPE_NAME}[${JSON.stringify(resultKey)}`
+
+  const addResult = (name: string, ty: string): Node | undefined =>
+    resultTypeNode
+      ?.asKind(SyntaxKind.TypeAliasDeclaration)
+      ?.getChildAtIndexIfKind(3, SyntaxKind.TypeLiteral)
+      ?.addProperty({
+        name: JSON.stringify(name),
+        type: `{ output: ${ty} }`,
+      })
+
+  const createResult = (ty: string): [string, Node | undefined] => {
+    const resultKey = uuid()
+    const node = addResult(resultKey, ty)
+    return [resultKey, node]
+  }
+
+  const customEffects: Record<string, (...args: Type[]) => any> = {}
+
+  return {
+    sourceFile,
+    typeChecker,
+    entryPoint,
+    typeToString,
+
+    createResult,
+    getResultExpr,
+    printResultNode: () => console.log(resultTypeNode?.print()),
+
+    addCustomEffect: (name, expr) => {
+      const func = eval(expr)
+      Object.assign(customEffects, { [name]: func })
+    },
+    runCustomEffect: async (name, args) => {
+      const output = await customEffects[name]?.(...args)
+      if (output) {
+        const [resultKey, _] = createResult(`${JSON.stringify(output)}`)
+        return [resultKey]
+      }
+      return []
+    },
+    hasCustomEffect: (name) => customEffects[name] !== undefined,
+  }
+}
+