"use strict";

const assert = require("assert");
const types = require("@babel/types");
const template = require("@babel/template").default;

const templateExpression = require("./util/template-expression");

// FIXME: Auto-generate argument list based on exposed API surface?
let tmplModule = template(`
	module.exports = function({ builtins, $memoize, $handleArgument, $assertUniqueKeys }) {
		return %%contents%%;
	};
`);

let tmplIdentifierReference = templateExpression(`(
	%%name%%()
)`);

let trivial = {
	name: "trivial-transforms",
	visitors: {
		// Trivial transforms
		NixParenthesizedExpression: (node) => node.expression,
		Program: (_node, { setContext, defer }) => {
			setContext(null, "identifierType", "reference");

			return defer((node) => {
				assert(node.body.length === 1);
				return tmplModule({ contents: node.body[0] });
			});
		},
		NixIdentifier: (node, { getContext }) => {
			// FIXME: Mangle reserved keywords like `const`
			if (getContext("identifierType") === "define") {
				return types.identifier(node.name);
			} else { // reference
				return tmplIdentifierReference({ name: node.name });
			}
		},
		NixBinaryOperation: (_node, { defer }) => {
			return defer((node) => {
				// FIXME: Verify that all the 'operator' values match between Nix and JS!
				return types.binaryExpression(node.operator, node.left, node.right);
			});
		}
	}
};

module.exports = [
	require("./desugar-inherits"),
	require("./desugar-attrsets"),
	require("./desugar-let-attribute-set"),
	require("./desugar-interpolation-expressions"),
	require("./mangle-identifiers"),
	require("./let-in"),
	require("./literals"),
	require("./functions"),
	require("./attribute-sets"),
	trivial,
];