---
phase: 13-fix-duplicate-generations
plan: 01
type: execute
---

<objective>
Add content-based deduplication to the auto-save generations flow.

Purpose: Prevent duplicate images/videos in the generations folder when the same content is generated multiple times. Currently every generation is saved regardless of whether identical content already exists.

Output: Modified save-generation API that checks content hash before writing, returns existing file if duplicate found.
</objective>

<execution_context>
@~/.claude/get-shit-done/workflows/execute-phase.md
@~/.claude/get-shit-done/templates/summary.md
</execution_context>

<context>
@.planning/PROJECT.md
@.planning/ROADMAP.md
@.planning/STATE.md

**Key source files:**
@src/app/api/save-generation/route.ts - Current save logic (no deduplication)
@src/utils/imageStorage.ts - Existing hash logic for workflow images (lines 206-211)

**Current behavior:**
- `workflowStore.ts` calls `/api/save-generation` with `imageId = Date.now()` for every generation
- `/api/save-generation` saves to `{directoryPath}/{imageId}.{ext}` unconditionally
- No content hash check - identical images get duplicate files

**Target behavior:**
- Hash image/video content on server before saving
- Check if file with same hash already exists in generations folder
- If duplicate: return existing file path, don't create new file
- If unique: save file with hash-based filename, return new path

**Prior art:**
- `imageStorage.ts:saveImageAndGetId` uses client-side hash of substring samples (lines 206-211)
- Server-side crypto hash is more reliable and works for URL-fetched content
</context>

<tasks>

<task type="auto">
  <name>Task 1: Add content hashing to save-generation API</name>
  <files>src/app/api/save-generation/route.ts</files>
  <action>
    Add server-side content hashing using Node.js crypto:

    1. Import `crypto` module at top
    2. After buffer is created (line ~95-108), compute content hash:
       ```typescript
       const contentHash = crypto.createHash('md5').update(buffer).digest('hex');
       ```
    3. Check if file with this hash already exists in directory:
       - List files in directoryPath
       - Check if any filename starts with the hash
       - If found, return early with existing file info
    4. Use hash-prefixed filename instead of timestamp-based:
       - Change filename format to: `{hash}_{promptSnippet}.{extension}`
       - Keep prompt snippet for human readability
       - Hash ensures uniqueness without timestamp

    Why MD5: Fast for binary data, collision resistance not critical for dedup (worst case: rare false duplicate). SHA256 is overkill for local file dedup.

    Why hash in filename: Enables O(1) duplicate check via glob/fs.existsSync pattern match instead of reading all files.
  </action>
  <verify>
    Build passes: `npm run build` succeeds without errors.
    Manual test: Generate same image twice, second generation should return existing file path without creating duplicate.
  </verify>
  <done>
    - MD5 hash computed from buffer content
    - Filename uses hash prefix: `{hash}_{prompt}.{ext}`
    - Duplicate check finds existing files by hash prefix
    - Returns existing file info if duplicate found
    - New files saved with hash-prefixed name
  </done>
</task>

<task type="auto">
  <name>Task 2: Add duplicate detection response handling</name>
  <files>src/app/api/save-generation/route.ts</files>
  <action>
    Enhance response to indicate whether file was deduplicated:

    1. Add `isDuplicate: boolean` field to response JSON
    2. When returning existing file (duplicate found):
       - Set `isDuplicate: true`
       - Return existing `filePath` and `filename`
       - Log deduplication event for observability
    3. When saving new file:
       - Set `isDuplicate: false`
       - Return new `filePath` and `filename` as before

    This allows callers (workflowStore) to know if deduplication occurred, useful for debugging and future UI feedback.
  </action>
  <verify>
    Test duplicate scenario: Generate same content twice, second call returns `{ success: true, isDuplicate: true, filePath: existing }`.
    Test unique scenario: Generate new content, returns `{ success: true, isDuplicate: false, filePath: new }`.
  </verify>
  <done>
    - Response includes `isDuplicate` boolean field
    - Duplicate files logged: "Generation deduplicated: existing file found"
    - Unique files logged: "Generation saved" (existing log)
  </done>
</task>

</tasks>

<verification>
Before declaring phase complete:
- [ ] `npm run build` succeeds without errors
- [ ] Generate same prompt twice → second returns existing file (no new file created)
- [ ] Generate different prompt → new file created with hash prefix
- [ ] Response includes `isDuplicate` field
- [ ] Existing generations folder functionality preserved
</verification>

<success_criteria>
- All tasks completed
- All verification checks pass
- No duplicate files created for identical content
- Backward compatible: existing generations still accessible
- Hash-based filenames enable fast duplicate lookup
</success_criteria>

<output>
After completion, create `.planning/phases/13-fix-duplicate-generations/13-01-SUMMARY.md`
</output>