Design an Applicant Tracking System (ATS)

Design a system for an Applicant Tracking System (ATS) that supports offer letter templates with macros. Templates contain placeholders that are replaced with actual values during document generation. There are two types of fields: (1) Direct Fields — values provided directly by the user (e.g., FixedSalary, BonusPercentage, JoiningBonus, CandidateName); (2) Calculated Fields — values derived from formulas referencing other fields (e.g., BonusAmount = IncentiveBonus + (BonusPercentage * FixedSalary) / 100, CTC = FixedSalary + JoiningBonus + BonusAmount). The system must resolve field dependencies and substitute all placeholders in the template to produce the final document.