Chibuzor Ezeamaku Case Study
Reporting Engine · Client Project

Document-Based Reporting Engine

A dynamic reporting engine that turns document and spreadsheet templates into finished client deliverables — pattern-driven find-and-replace over performant, DRY SQL, eliminating 95%+ of the hand-coding each report used to require.

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What it is

Producing client reports used to mean writing bespoke code for each new deliverable. This engine replaces that with a template-driven pipeline: a document or Excel template carries the structure and a set of well-defined placeholder patterns, and the engine resolves them with live data in a predetermined, repeatable way.

The result is that a new report type becomes a matter of authoring a template — not writing and maintaining yet another one-off codebase. I owned it end-to-end, from conception to ship.

Built for a client, so the deep specifics stay private — what follows is the shape of the system and the engineering behind it.

What makes it interesting

Templates as the contract

Excel and document templates hold both the layout and a set of placeholder patterns. The output’s shape lives in the template, so a new deliverable doesn’t require touching the engine.

Pattern-driven substitution

A refactored regex pipeline finds each placeholder and replaces it with the right data, deterministically. The find-and-replace is the hot path, so it was rebuilt for both correctness and speed.

Adapter pattern at the core

Pluggable adapters map each report or template family to its data, isolating per-deliverable variation from the engine core — new shapes plug in without destabilizing what already ships.

DRY, performant SQL

A shared, tuned query layer feeds the engine. Overlapping queries were consolidated into reusable, performant statements instead of copy-pasted SQL scattered per report.

Notable engineering decisions
Rebuild the regex pipeline

Placeholder resolution runs on every report, so the find-and-replace logic was refactored for correctness and performance rather than left as the bottleneck it had been.

Consolidate the SQL

Reporting queries were made DRY and performant — one tuned, reusable query layer rather than near-duplicate statements maintained per deliverable.

Isolate variation behind adapters

The adapter pattern keeps client- and report-specific differences out of the core, so the engine stays small while the catalog of supported deliverables grows.

Hold output fidelity

Generated documents match the client’s exact formatting expectations — high-quality output that drops straight into the deliverable without manual cleanup.

Tech & approach
CoreC# / .NETOwned end-to-end, conception to ship.
TemplatingExcel & document templatesStructure and placeholder patterns authored, not coded.
SubstitutionRefactored regex pipelineDeterministic find-and-replace; rebuilt for speed.
DataDRY, tuned SQLOne reusable, performant query layer.
PatternAdapterPer-deliverable variation isolated from the core.
Impact95%+ less custom codePer-report hand-coding all but eliminated.