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

import type {
  CanvasGenerationDialogState,
  CanvasLayer,
  CanvasViewport,
} from './ImageCanvasEditorTypes';
import {
  centerViewportOnPlacement,
  chooseGenerationPlacement,
} from './ImageCanvasGenerationPlacementModel';

const canvasSize = { width: 900, height: 640 };
const viewport: CanvasViewport = { x: 10, y: 20, scale: 2 };
const frame = {
  x: 0,
  y: 0,
  width: 420,
  height: 420,
  originalWidth: 2048,
  originalHeight: 2048,
};

function layer(overrides: Partial<CanvasLayer>): CanvasLayer {
  return {
    id: 'layer-1',
    resourceId: 'resource-1',
    title: '图片',
    src: '/image.png',
    x: 0,
    y: 0,
    width: 100,
    height: 100,
    originalWidth: 100,
    originalHeight: 100,
    zIndex: 1,
    sourceType: 'uploaded',
    ...overrides,
  };
}

function generationDialog(
  overrides: Partial<CanvasGenerationDialogState>,
): CanvasGenerationDialogState {
  return {
    id: 'dialog-1',
    mode: 'generate',
    prompt: '',
    status: 'idle',
    placeholder: {
      x: 0,
      y: 0,
      width: 100,
      height: 100,
      originalWidth: 2048,
      originalHeight: 2048,
    },
    ...overrides,
  };
}

describe('ImageCanvasGenerationPlacementModel', () => {
  it('places an empty-canvas generation frame at the current viewport center', () => {
    const placement = chooseGenerationPlacement({
      canvasSize,
      viewport,
      frame,
      layers: [],
      generationDialogs: [],
    });

    expect(placement).toEqual({
      x: 10,
      y: -60,
      width: 420,
      height: 420,
      originalWidth: 2048,
      originalHeight: 2048,
    });
  });

  it('keeps the nearest non-overlapping gap from visible layers and generation placeholders', () => {
    const placement = chooseGenerationPlacement({
      canvasSize,
      viewport,
      frame: { ...frame, width: 100, height: 100 },
      layers: [
        layer({ id: 'center', x: 170, y: 110, width: 120, height: 120 }),
        layer({ id: 'right', x: 322, y: 110, width: 100, height: 120 }),
        layer({
          id: 'hidden',
          hidden: true,
          x: 18,
          y: 118,
          width: 100,
          height: 100,
        }),
      ],
      generationDialogs: [
        {
          id: 'dialog-left',
          mode: 'generate',
          prompt: '',
          status: 'idle',
          placeholder: {
            x: 18,
            y: 118,
            width: 100,
            height: 100,
            originalWidth: 2048,
            originalHeight: 2048,
          },
        },
      ],
    });

    expect(placement.x).toBe(170);
    expect(placement.y).toBe(-22);
  });

  it('does not treat hidden layers as generation placement blockers', () => {
    const placement = chooseGenerationPlacement({
      canvasSize,
      viewport,
      frame: { ...frame, width: 100, height: 100 },
      layers: [
        layer({
          id: 'hidden-center',
          hidden: true,
          x: 170,
          y: 110,
          width: 100,
          height: 100,
        }),
      ],
      generationDialogs: [],
    });

    expect(placement.x).toBe(170);
    expect(placement.y).toBe(100);
  });

  it('chooses the nearest empty slot when multiple blockers surround the viewport center', () => {
    const placement = chooseGenerationPlacement({
      canvasSize: { width: 1000, height: 1000 },
      viewport: { x: 500, y: 500, scale: 1 },
      frame: { ...frame, width: 100, height: 100 },
      layers: [
        layer({
          id: 'left-blocker',
          x: -148,
          y: -68,
          width: 96,
          height: 136,
        }),
        layer({
          id: 'top-blocker',
          x: -68,
          y: -148,
          width: 136,
          height: 96,
        }),
      ],
      generationDialogs: [],
    });

    expect(placement.x).toBe(-20);
    expect(placement.y).toBe(-20);
  });

  it('avoids existing generation placeholders when choosing a new placement', () => {
    const placement = chooseGenerationPlacement({
      canvasSize,
      viewport,
      frame: { ...frame, width: 100, height: 100 },
      layers: [],
      generationDialogs: [
        generationDialog({
          id: 'existing-placeholder',
          placeholder: {
            x: 170,
            y: 110,
            width: 100,
            height: 100,
            originalWidth: 2048,
            originalHeight: 2048,
          },
        }),
      ],
    });

    expect(placement.x).toBe(170);
    expect(placement.y).toBe(-22);
  });

  it('focuses the viewport on the chosen placement without changing zoom', () => {
    const zoomedViewport = { ...viewport, scale: 1.75 };
    const nextViewport = centerViewportOnPlacement({
      canvasSize,
      viewport: zoomedViewport,
      placement: {
        x: 170,
        y: 262,
        width: 100,
        height: 100,
        originalWidth: 2048,
        originalHeight: 2048,
      },
    });

    expect(nextViewport.scale).toBe(zoomedViewport.scale);
    expect(nextViewport).toEqual({ x: 65, y: -226, scale: 1.75 });
  });
});