import { describe, expect, it } from 'vitest';

import {
  canRedoResourceCanvasHistory,
  canUndoResourceCanvasHistory,
  captureResourceCanvasSnapshot,
  clearResourceCanvasHistory,
  createResourceCanvasHistory,
  MAX_RESOURCE_CANVAS_HISTORY_STEPS,
  pushResourceCanvasHistory,
  redoResourceCanvasHistory,
  resolveResourceCanvasRestoreEntries,
  undoResourceCanvasHistory,
} from '../src/features/resource-canvas/resourceCanvasHistoryModel';

function positions(
  entries: Array<[string, number, number, boolean?]>,
): ReturnType<typeof captureResourceCanvasSnapshot>['entries'] {
  return entries.map(([resourceId, x, y, manuallyPlaced = true]) => ({
    resourceId,
    section: 'document',
    x,
    y,
    manuallyPlaced,
  }));
}

describe('resource canvas history model', () => {
  it('按 resourceId 排序落快照，map 顺序不影响相等判定', () => {
    const left = captureResourceCanvasSnapshot(
      positions([
        ['asset:b', 2, 2],
        ['asset:a', 1, 1],
      ]),
    );
    const right = captureResourceCanvasSnapshot(
      positions([
        ['asset:a', 1, 1],
        ['asset:b', 2, 2],
      ]),
    );

    expect(left.entries.map((entry) => entry.resourceId)).toEqual([
      'asset:a',
      'asset:b',
    ]);
    expect(left).toEqual(right);
  });

  it('push 连续相同快照不产生新历史条目', () => {
    const snapshot = captureResourceCanvasSnapshot(
      positions([['asset:a', 1, 1]]),
    );
    const first = pushResourceCanvasHistory(createResourceCanvasHistory(), {
      label: '移动卡片',
      snapshot,
    });
    const second = pushResourceCanvasHistory(first, {
      label: '移动卡片',
      snapshot: captureResourceCanvasSnapshot(positions([['asset:a', 1, 1]])),
    });

    expect(first.undoStack).toHaveLength(1);
    expect(second).toBe(first);
  });

  it('push 后重做分支失效，撤回栈有界', () => {
    let history = createResourceCanvasHistory();
    for (
      let index = 0;
      index < MAX_RESOURCE_CANVAS_HISTORY_STEPS + 5;
      index += 1
    ) {
      history = pushResourceCanvasHistory(history, {
        label: `移动 ${index}`,
        snapshot: captureResourceCanvasSnapshot(
          positions([['asset:a', index, index]]),
        ),
      });
    }
    expect(history.undoStack).toHaveLength(MAX_RESOURCE_CANVAS_HISTORY_STEPS);
    expect(history.undoStack[0]?.label).toBe('移动 5');

    const undone = undoResourceCanvasHistory(
      history,
      captureResourceCanvasSnapshot(positions([['asset:a', 99, 99]])),
    )!;
    expect(canRedoResourceCanvasHistory(undone.history)).toBe(true);

    const pushed = pushResourceCanvasHistory(undone.history, {
      label: '新的移动',
      snapshot: captureResourceCanvasSnapshot(
        positions([['asset:a', 120, 120]]),
      ),
    });
    expect(canRedoResourceCanvasHistory(pushed)).toBe(false);
  });

  it('撤销与重做互为逆操作，并回填当前快照', () => {
    const moved = captureResourceCanvasSnapshot(
      positions([['asset:a', 10, 20]]),
    );
    let history = pushResourceCanvasHistory(createResourceCanvasHistory(), {
      label: '移动卡片',
      snapshot: moved,
    });

    const current = captureResourceCanvasSnapshot(
      positions([['asset:a', 60, 70]]),
    );
    const undone = undoResourceCanvasHistory(history, current)!;
    expect(undone.snapshot).toEqual(moved);
    expect(undone.label).toBe('移动卡片');
    expect(canUndoResourceCanvasHistory(undone.history)).toBe(false);

    const redone = redoResourceCanvasHistory(undone.history, moved)!;
    expect(redone.snapshot).toEqual(current);
    expect(canRedoResourceCanvasHistory(redone.history)).toBe(false);
    expect(canUndoResourceCanvasHistory(redone.history)).toBe(true);
    history = redone.history;
    expect(history.redoStack).toHaveLength(0);
  });

  it('空历史撤销/重做返回 null，清空后两个栈都为空', () => {
    const empty = createResourceCanvasHistory();
    expect(undoResourceCanvasHistory(empty, { entries: [] })).toBeNull();
    expect(redoResourceCanvasHistory(empty, { entries: [] })).toBeNull();

    const history = pushResourceCanvasHistory(empty, {
      label: '移动卡片',
      snapshot: captureResourceCanvasSnapshot(positions([['asset:a', 1, 1]])),
    });
    const cleared = clearResourceCanvasHistory(history);
    expect(cleared.undoStack).toHaveLength(0);
    expect(cleared.redoStack).toHaveLength(0);
    expect(clearResourceCanvasHistory(cleared)).toBe(cleared);
  });

  it('只把与当前不一致的位置写回后端', () => {
    const snapshot = captureResourceCanvasSnapshot(
      positions([
        ['asset:a', 10, 20],
        ['asset:b', 30, 40],
      ]),
    );
    const restore = resolveResourceCanvasRestoreEntries(
      snapshot,
      positions([
        ['asset:a', 10, 20],
        ['asset:b', 99, 98],
        ['asset:c', 1, 1],
      ]),
    );

    expect(restore.map((entry) => entry.resourceId)).toEqual(['asset:b']);
  });

  it('快照里不存在的资源不会在撤销时被新建出来', () => {
    const snapshot = captureResourceCanvasSnapshot(
      positions([['asset:deleted', 10, 20]]),
    );
    expect(
      resolveResourceCanvasRestoreEntries(snapshot, positions([])),
    ).toEqual([]);
  });
});