refactor(opencode): cut returns in packages/opencode/src/acp/content.ts

[JakePJakeP]

P1B: Starter Task: Refactoring PR

1. Issue

Link to the associated GitHub issue:
#77

Full path to the refactored file:
packages/opencode/src/acp/content.ts

What do you think this file does?
It converts Agent Client Protocol (ACP) content blocks into OpenCode prompt parts, and the reverse for replay: text, images, resource links, and embedded resources become session text/file parts (and later ACP content chunks).

What is the scope of your refactoring within that file?
Only contentBlockToParts and helpers extracted below it: textBlockToParts, imageBlockToParts, imageBlockUrl, resourceLinkBlockToParts, resourceBlockToParts, resourceTextToParts, resourceBlobToParts, plus the typed handlers map. partToContentChunks and the rest of the file were not changed.

Which Qlty‑reported issue did you address?
Function with many returns (count = 11) on contentBlockToParts (line 30). The same function also had Function with high complexity (count = 33); the file also showed High total complexity (count = 61).

2. Refactoring

How did the specific issue you chose impact the codebase’s maintainability?
Eleven return paths in one switch (text, several image URL shapes, resource_link, nested resource text/blob, default) made the conversion hard to scan and risky to change, because a mime or URL tweak could easily break a sibling branch.

What changes did you make to resolve the issue?
I kept the public API contentBlockToParts(block): PromptPart[] and copied each case into helpers below it, then collapsed the export to one dispatch: return handlers[block.type]?.(block as never) ?? []. URL handling, mime fallbacks, Windows slash normalize, and data-URL behavior were left as-is.

How do your changes improve maintainability? Did you consider alternatives?
Each block type is now a small named function, so a future ACP type or image-URL rule can be edited without rereading the whole converter. I considered leaving a 5-return switch, but Qlty’s bar was “many returns,” so I used the typed handler map instead of any or a still-smelly switch.

3. Validation

How did you validate that the change is correct?
Locally: bun lint from the repo root; bun test test/acp/content.test.ts from packages/opencode (19 pass, including new cases that hit the extracted helpers); coverage via bun test --coverage --coverage-dir=./coverage test/acp/content.test.ts (src/acp/content.ts 100% functions / 83.84% lines, with remaining misses in unchanged replay helpers); and qlty smells --no-snippets packages/opencode/src/acp/content.ts afterward reported no smells. CI on this branch adds an acp content job that runs only that test file.

Attach a screenshot of the test coverage showing the lines were executed by the tests.

Attach a screenshot showing the tests that cover the change passing during CI.

Attach a screenshot of qlty smells --no-snippets <full/path/to/file.ts> showing fewer reported issues after the changes.
Before Changes:

After Changes: