zkoss/zk

// eslint-disable-next-line no-undef
module.exports = function ({types: t}) {

    function createNestedMemberExpression(identifiers) {
        if (identifiers.length === 1) {
            return t.identifier(identifiers[0]);
        } else {
            const [head, ...tail] = identifiers;
            return t.memberExpression(
                createNestedMemberExpression(tail),
                t.identifier(head)
            );
        }
    }

    return {
        visitor: {
            Program: {
                exit(path) {
                    let dir = this.file.opts.filename.replace(/-/g, '_').split('/');
                    const jsLoc = dir.findIndex(x => x === 'js'),
                        file = dir[dir.length - 1],
                        exports = {};

                    // pass if [not in js folder] or [not ts file] or [is global.d.ts] or [is index.ts]
                    if (jsLoc === -1 || !file.endsWith('ts') || file === 'global.d.ts' || file === 'index.ts') return;

                    // simplify whole dir
                    dir = dir.slice(jsLoc + 1);
                    dir[dir.length - 1] = file.replace('.ts', '');

                    // sort order for follow-up
                    dir.unshift('window');
                    dir.push('_');
                    dir.reverse();

                    // visit all nodes
                    path.node.body.forEach((node, index) => {
                        if (t.isVariableDeclaration(node)) {
                            node.declarations.forEach((declaration) => {
                                if (t.isIdentifier(declaration.id)) {
                                    exports[declaration.id.name] = declaration.id.name;
                                }
                            });
                        } else if (t.isFunctionDeclaration(node) && t.isIdentifier(node.id)) {
                            exports[node.id.name] = node.id.name;
                        }
                    });

                    // add check-exist if statements
                    for (let i = dir.length - 2; i > 0; i--) {
                        const nestedExpression = createNestedMemberExpression(dir.slice(i));
                        path.pushContainer('body',
                            t.ifStatement(
                                t.unaryExpression('!', nestedExpression),
                                t.expressionStatement(
                                    t.assignmentExpression(
                                        '=',
                                        nestedExpression,
                                        t.objectExpression([])
                                    )
                                )
                            )
                        );
                    }

                    // export all global variables and functions
                    path.pushContainer('body',
                        // window.x.x.x._ = {...}
                        t.expressionStatement(
                            t.assignmentExpression(
                                '=',
                                createNestedMemberExpression(dir),
                                t.objectExpression(
                                    Object.entries(exports).map(([k, v]) => {
                                        return t.objectProperty(t.identifier(k), t.identifier(v));
                                    })
                                )
                            )
                        )
                    );

                }
            }
        }
    };
};