feat: add execution plan helper

src/core/execution-plan.ts

@@ -0,0 +1,75 @@
+import { FileItem } from '../types/platform';
+import { Task } from '../types/core';
+import {
+  ConflictResolution,
+  ConflictResult,
+  resolveBatchConflicts,
+} from './conflict-detector';
+
+export interface ExecutionPlanInput {
+  files: FileItem[];
+  newNames: string[];
+  conflicts?: Map<string, ConflictResult>;
+  resolution?: ConflictResolution | null;
+  skipUnchanged?: boolean;
+}
+
+export interface ExecutionPlanResult {
+  resolvedNames: string[];
+  tasks: Task[];
+  skippedIndexes: number[];
+}
+
+export function buildExecutionPlan({
+  files,
+  newNames,
+  conflicts,
+  resolution,
+  skipUnchanged = true,
+}: ExecutionPlanInput): ExecutionPlanResult {
+  if (files.length !== newNames.length) {
+    throw new Error('Files and newNames length mismatch');
+  }
+
+  const conflictMap = conflicts ?? new Map<string, ConflictResult>();
+
+  let resolvedNames = newNames.slice();
+
+  if (resolution && conflictMap.size > 0) {
+    switch (resolution) {
+      case ConflictResolution.AUTO_NUMBER:
+        resolvedNames = resolveBatchConflicts(files, newNames, conflictMap);
+        break;
+      case ConflictResolution.SKIP:
+        resolvedNames = newNames.map((name, index) => {
+          const file = files[index];
+          const conflict = conflictMap.get(file.id);
+          return conflict?.hasConflict ? file.name : name;
+        });
+        break;
+      case ConflictResolution.OVERWRITE:
+      default:
+        resolvedNames = newNames.slice();
+        break;
+    }
+  }
+
+  const tasks: Task[] = [];
+  const skippedIndexes: number[] = [];
+
+  resolvedNames.forEach((resolvedName, index) => {
+    const file = files[index];
+    if (skipUnchanged && resolvedName === file.name) {
+      skippedIndexes.push(index);
+      return;
+    }
+
+    tasks.push({
+      file,
+      newName: resolvedName,
+      index,
+    });
+  });
+
+  return { resolvedNames, tasks, skippedIndexes };
+}

tests/unit/execution-plan.test.ts

@@ -0,0 +1,40 @@
+import { describe, it, expect } from 'vitest';
+import { buildExecutionPlan } from '../../src/core/execution-plan';
+import { checkBatchConflicts, ConflictResolution } from '../../src/core/conflict-detector';
+
+const files = [
+  { id: '1', name: 'a.txt', ext: '.txt', parentId: '0', size: 1, mtime: 1 },
+  { id: '2', name: 'b.txt', ext: '.txt', parentId: '0', size: 1, mtime: 1 },
+];
+
+describe('buildExecutionPlan', () => {
+  it('auto-number resolves duplicate names and skips unchanged', () => {
+    const newNames = ['same.txt', 'same.txt'];
+    const conflicts = checkBatchConflicts(files as any, newNames);
+
+    const plan = buildExecutionPlan({
+      files: files as any,
+      newNames,
+      conflicts,
+      resolution: ConflictResolution.AUTO_NUMBER,
+    });
+
+    expect(plan.resolvedNames[0]).toMatch(/same\(1\)\.txt/);
+    expect(plan.resolvedNames[1]).toMatch(/same\(2\)\.txt/);
+    expect(plan.tasks.length).toBe(2);
+  });
+
+  it('skip strategy preserves original names', () => {
+    const newNames = ['same.txt', 'same.txt'];
+    const conflicts = checkBatchConflicts(files as any, newNames);
+
+    const plan = buildExecutionPlan({
+      files: files as any,
+      newNames,
+      conflicts,
+      resolution: ConflictResolution.SKIP,
+    });
+
+    expect(plan.resolvedNames).toEqual(['a.txt', 'b.txt']);
+  });
+});