import type {
  CanvasGenerationDialogState,
  CanvasHistoryAction,
  CanvasHistorySnapshot,
  CanvasLayer,
  GenerateDialogState,
} from './ImageCanvasEditorTypes';

const CANVAS_HISTORY_ACTION_LABELS: Record<
  CanvasHistoryAction['type'],
  string
> = {
  'move-image': '移动图片',
  'move-generation-result': '移动生成结果',
  'delete-image': '删除图片',
  'delete-generation-result': '删除生成结果',
  'cut-image': '剪切图片',
  'paste-image': '粘贴图片',
  'duplicate-image': '复制图片',
  'add-image': '添加图片',
  'upload-image': '上传图片',
  'generate-image': '生成图片',
  'expand-image': '扩展图片',
  'remove-background': '移除背景',
  'split-atlas': '拆分图集',
  'replace-image': '替换图片',
  'show-image': '显示图片',
  'hide-image': '隐藏图片',
  'change-layer-order': '调整图片层级',
  'group-images': '组合图片',
  'ungroup-images': '取消组合',
  'lock-image': '锁定图片',
  'unlock-image': '解锁图片',
  'flip-image': '翻转图片',
  'change-asset-kind': '修改素材类型',
  'change-viewport': '调整画布视图',
};

const PROTECTED_CANVAS_HISTORY_ACTION_TYPES = new Set<
  CanvasHistoryAction['type']
>([
  'paste-image',
  'duplicate-image',
  'add-image',
  'upload-image',
  'generate-image',
  'expand-image',
  'remove-background',
  'split-atlas',
  'replace-image',
]);

export function formatCanvasHistoryAction(action: CanvasHistoryAction): string {
  return CANVAS_HISTORY_ACTION_LABELS[action.type];
}

export function isProtectedCanvasHistoryAction(
  action: CanvasHistoryAction,
): boolean {
  return PROTECTED_CANVAS_HISTORY_ACTION_TYPES.has(action.type);
}

function hasSameStableMediaReference(
  current: {
    src: string;
    objectKey?: string | null;
    assetObjectId?: string | null;
  },
  target: {
    src: string;
    objectKey?: string | null;
    assetObjectId?: string | null;
  },
): boolean {
  if (current.objectKey && target.objectKey) {
    return current.objectKey === target.objectKey;
  }
  if (current.assetObjectId && target.assetObjectId) {
    return current.assetObjectId === target.assetObjectId;
  }
  return current.src === target.src;
}

function hasSameImageSequenceFrames(
  current: CanvasLayer,
  target: CanvasLayer,
): boolean {
  const currentFrames = current.imageSequenceFrames ?? [];
  const targetFrames = target.imageSequenceFrames ?? [];
  if (currentFrames.length !== targetFrames.length) {
    return false;
  }
  return currentFrames.every((currentFrame, index) => {
    const targetFrame = targetFrames[index];
    return (
      targetFrame !== undefined &&
      currentFrame.frameIndex === targetFrame.frameIndex &&
      hasSameStableMediaReference(
        {
          src: currentFrame.imageSrc,
          objectKey: currentFrame.objectKey,
          assetObjectId: currentFrame.assetObjectId,
        },
        {
          src: targetFrame.imageSrc,
          objectKey: targetFrame.objectKey,
          assetObjectId: targetFrame.assetObjectId,
        },
      )
    );
  });
}

function hasSameLayerContent(
  current: CanvasLayer,
  target: CanvasLayer,
): boolean {
  return (
    (current.mediaType ?? 'image') === (target.mediaType ?? 'image') &&
    hasSameStableMediaReference(current, target) &&
    hasSameImageSequenceFrames(current, target)
  );
}

function cloneDialogPlaceholder(
  dialog: GenerateDialogState,
): GenerateDialogState['placeholder'] {
  return dialog.placeholder ? { ...dialog.placeholder } : undefined;
}

function mergeLayerForHistoryRestore(
  target: CanvasLayer,
  current: CanvasLayer | undefined,
  restoreAssetKind: boolean,
): CanvasLayer {
  if (!current) {
    return { ...target };
  }
  const resourceAssetKind =
    current.resourceAssetKind ?? target.resourceAssetKind;
  const restoresLayerOverride =
    target.assetKindOverride !== undefined ||
    current.assetKindOverride !== undefined;
  const assetKindOverride = restoreAssetKind
    ? (target.assetKindOverride ?? null)
    : current.assetKindOverride;
  return {
    ...current,
    x: target.x,
    y: target.y,
    zIndex: target.zIndex,
    groupId: target.groupId,
    ...(resourceAssetKind !== undefined ? { resourceAssetKind } : {}),
    ...(restoresLayerOverride ? { assetKindOverride } : {}),
    assetKind: restoreAssetKind
      ? restoresLayerOverride
        ? (assetKindOverride ?? resourceAssetKind ?? null)
        : target.assetKind
      : current.assetKind,
    hidden: target.hidden,
    locked: target.locked,
    flipX: target.flipX,
    flipY: target.flipY,
  };
}

function mergeDialogPlaceholderForHistoryRestore(
  target: GenerateDialogState,
  current: GenerateDialogState,
): GenerateDialogState['placeholder'] {
  if (!current.placeholder) {
    return cloneDialogPlaceholder(target);
  }
  if (!target.placeholder) {
    return cloneDialogPlaceholder(current);
  }
  return {
    ...current.placeholder,
    x: target.placeholder.x,
    y: target.placeholder.y,
  };
}

function mergeDialogForHistoryRestore<
  TTarget extends GenerateDialogState,
  TCurrent extends GenerateDialogState,
>(target: TTarget, current: TCurrent | undefined): TTarget | TCurrent {
  if (!current) {
    return {
      ...target,
      placeholder: cloneDialogPlaceholder(target),
    };
  }
  return {
    ...current,
    composerOpen: target.composerOpen,
    placeholder: mergeDialogPlaceholderForHistoryRestore(target, current),
  };
}

export function mergeCanvasHistorySnapshotForRestore({
  current,
  target,
  assetKindLayerIds,
}: {
  current: CanvasHistorySnapshot;
  target: CanvasHistorySnapshot;
  assetKindLayerIds?: ReadonlySet<string>;
}): CanvasHistorySnapshot {
  const currentLayerById = new Map(
    current.layers.map((layer) => [layer.id, layer] as const),
  );
  const currentDialogById = new Map<string, GenerateDialogState>();
  for (const dialog of current.inactiveGenerateDialogs) {
    currentDialogById.set(dialog.id, dialog);
  }
  if (current.generateDialog?.id) {
    currentDialogById.set(current.generateDialog.id, current.generateDialog);
  }

  const mergeTargetDialog = <T extends GenerateDialogState>(dialog: T): T =>
    mergeDialogForHistoryRestore(
      dialog,
      dialog.id ? currentDialogById.get(dialog.id) : undefined,
    ) as T;

  return {
    ...target,
    layers: target.layers.map((layer) =>
      mergeLayerForHistoryRestore(
        layer,
        currentLayerById.get(layer.id),
        assetKindLayerIds?.has(layer.id) ?? true,
      ),
    ),
    generateDialog: target.generateDialog
      ? mergeTargetDialog(target.generateDialog)
      : null,
    inactiveGenerateDialogs: target.inactiveGenerateDialogs.map(
      (dialog): CanvasGenerationDialogState => mergeTargetDialog(dialog),
    ),
  };
}

export function canRestoreCanvasHistorySnapshotWithoutContentLoss({
  current,
  target,
}: {
  current: CanvasHistorySnapshot;
  target: CanvasHistorySnapshot;
}): boolean {
  const targetLayerById = new Map(
    target.layers.map((layer) => [layer.id, layer] as const),
  );

  const preservesLayers = current.layers.every((currentLayer) => {
    const targetLayer = targetLayerById.get(currentLayer.id);
    if (!targetLayer) {
      return false;
    }
    if (!currentLayer.hidden && targetLayer.hidden) {
      return false;
    }
    return hasSameLayerContent(currentLayer, targetLayer);
  });
  if (!preservesLayers) {
    return false;
  }

  const getDialogIds = (snapshot: CanvasHistorySnapshot): Set<string> =>
    new Set(
      [
        snapshot.generateDialog?.id,
        ...snapshot.inactiveGenerateDialogs.map((dialog) => dialog.id),
      ].filter((dialogId): dialogId is string => Boolean(dialogId)),
    );
  const targetDialogIds = getDialogIds(target);

  return [...getDialogIds(current)].every((dialogId) =>
    targetDialogIds.has(dialogId),
  );
}