PRD: Charting Refactor Checklist

Status: Completed (2026-01-31)

Goals

• Simplify the charting surface area so common workflows read clearly and predictably.
• Reduce conditional branching for time axis behavior (REAL_TIME vs BAR_INDEX).
• Separate dataset creation, axis configuration, renderer styling, and overlay composition.
• Keep public APIs stable while making internal responsibilities easier to test.

Guiding principles

• Tests first: add or expand unit tests before behavior-heavy refactors.
• Prefer small, isolated refactors over sweeping changes.
• Preserve current chart defaults and rendering behavior.
• Use existing ta4j style conventions (immutability, explicit imports, no reflection in tests).

Current focus area

• ChartWorkflow, ChartBuilder, TradingChartFactory (charting pipeline and time axis behavior).

Prioritized refactor opportunities

1. P0 - TradingChartFactory is a god class (dataset creation, axis config, renderer styling, overlays, tooltips). Minimal path: extract focused helpers (AxisFactory, DatasetFactory, OverlayRenderer) without changing behavior.
2. P0 - Repeated REAL_TIME vs BAR_INDEX branching across dataset creation, tooltips, and axis labels. Minimal path: introduce a TimeAxisModeStrategy interface that supplies axis, x-values, and tooltip formatting.
3. P1 - ChartWorkflow has many overloads with repeated validation. Minimal path: shared validation + chart creation helpers, keep current overloads delegating.
4. P1 - ChartBuilder stores timeAxisMode on builder but does not expose it in a dedicated config object. Minimal path: introduce ChartDefinitionMetadata or ChartContext that carries timeAxisMode + domain series.
5. P2 - Chart styling (background, anti-alias, title paint) is duplicated across factory methods. Minimal path: private applyChartStyling(JFreeChart chart) helper.

Implementation status

• Delivered TimeAxisMode (REAL_TIME/BAR_INDEX) and BAR_INDEX support across chart workflows.
• Extracted AxisFactory, DatasetFactory, and OverlayRendererFactory to reduce branching in TradingChartFactory.
• Centralized chart styling defaults to keep title/background/anti-aliasing consistent across chart types.
• Introduced ChartDefinitionMetadata and ChartContext to encapsulate domain series and time axis configuration.
• Added BAR_INDEX-focused tests for tooltips, analysis criterion overlays, and composite charts.
• Updated charting documentation to reference metadata inspection before rendering.

Test coverage gaps

• None noted after latest pass.

Step-by-step checklist

• Initial refactor scout completed (2026-01-31).
• Add BAR_INDEX dual-axis tooltip/date label tests.
• Add BAR_INDEX analysis criterion overlay test.
• Add BAR_INDEX overlay tooltip generator test.
• Extract TimeAxisModeStrategy and migrate one call site.
• Extract AxisFactory and replace in TradingChartFactory.
• Extract DatasetFactory (TimeSeries vs XYSeries) and update overlays.
• Extract OverlayRendererFactory for overlay renderers and tooltips.
• Route domain value selection through TimeAxisModeStrategy.
• Centralize ChartWorkflow validation/chart creation into helper methods.
• Centralize chart styling in TradingChartFactory.
• Introduce ChartDefinitionMetadata for time axis mode and domain series.
• Route ChartPlan/compose title handling through ChartDefinitionMetadata.
• Introduce ChartContext and use it across chart planning/rendering.
• Document chart metadata/consistent title styling in README.
• Verify full build after each refactor step (latest: 2026-01-31).

Open questions

• None.

References

• Charting guide
• Usage examples
• Wiki home