PHP Financial Data Analysis Script

I need a clean, well-documented PHP script that takes raw financial data as input, runs the necessary analysis, and returns structured results I can feed straight into my reporting stack. Scope of work • Ingest financial datasets (CSV, JSON, or an array passed in memory). • Perform the core data-analysis routines I specify—totals, averages, growth calculations, and any other metrics we agree on. • Output should be available both as an associative array and, on demand, as a downloadable CSV so I can drop it into Excel or Power BI without extra steps. • Code must stay framework-agnostic (pure PHP 8.x) and avoid heavy external dependencies; if you rely on a helper library, clear it with me first. • Efficiency matters: typical files sit around 50 MB, so streaming or chunked processing is essential to keep memory under control. Deliverables 1. The PHP script(s) with inline comments. 2. A short README explaining required PHP version, any composer installs, and example usage. 3. Sample input file and its expected output for quick verification. Acceptance criteria • Script completes analysis of a 50 MB CSV in under 30 seconds on a standard shared-hosting environment (1 vCPU, 1 GB RAM). • No fatal errors or notices when run with error_reporting(E_ALL). • Results match the sample output to within 0.1 % tolerance. Send a brief outline of your approach, including how you will handle memory management and any testing strategy you plan to use.