import { readFile, writeFile } from 'fs/promises';
import path from 'path';
import { fileURLToPath } from 'url';
import { LibraryItem, LibraryItems } from '@excalidraw/excalidraw/types'

// 如果新增了自定义素材，则需要运行这个脚本将素材同步到lib文件夹，以便下次合成素材库时，不会清除新增素材

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const inputFile = path.resolve(__dirname, '../library.excalidrawlib'); // 输入目录
const outputFile = path.resolve(__dirname, '../lib/library.excalidrawlib'); // 输出文件路径

interface ExportedLibraryData {
  type: string;
  version: number;
  source: string;
  libraryItems: LibraryItems;
}

function isExcalidrawlibFile(fileName: string): boolean {
  return fileName.endsWith('.excalidrawlib');
}

/**
 * checks if library item does not exist already in current library
 */
const isUniqueItem = (
  existingLibraryItems: LibraryItems,
  targetLibraryItem: LibraryItem,
) => {
  return !existingLibraryItems.find((libraryItem) => {
    if (libraryItem.elements.length !== targetLibraryItem.elements.length) {
      return false;
    }

    // detect z-index difference by checking the excalidraw elements
    // are in order
    return libraryItem.elements.every((libItemExcalidrawItem, idx) => {
      return (
        libItemExcalidrawItem.id === targetLibraryItem.elements[idx].id &&
        libItemExcalidrawItem.versionNonce ===
          targetLibraryItem.elements[idx].versionNonce
      );
    });
  });
};

function positionError(obj: any, msg?: string): false {
  console.error({
    error_msg: msg,
    error_obj: obj
  })
  return false
}

function isLibraryItem(obj: any): obj is LibraryItem {
  if (!obj) return positionError(obj, "LibraryItem obj does not exist")
  if (!obj.id || !obj.status || !obj.elements || !obj.created) return positionError(obj, "obj missing fields")
  if (typeof obj.id !== 'string') return positionError(obj, "obj.id type is not string")
  if (obj.status !== "published" && obj.status !== "unpublished") return positionError(obj, "obj.status value is wrong")
  if (!Array.isArray(obj.elements))  return positionError(obj, "obj.elements is not an array")
  if (typeof obj.created !== 'number') return positionError(obj, "obj.created type is not number")
  return true
}

function isLibraryItems(obj: any): obj is LibraryItems {
  if (!obj) return positionError(obj, "LibraryItems obj does not exist")
  if (!Array.isArray(obj)) return positionError(obj, "obj is not an array")
  for (const item of obj) {
    if (!isLibraryItem(item)) return positionError(obj, "LibraryItems is not an array")
  }
  return true
}

function isExportedLibraryData(obj: any): obj is ExportedLibraryData {
  if (!obj) return positionError(obj, "ExportedLibraryData obj does not exist")
  if (obj.type !== "excalidrawlib") return positionError(obj, "obj.type value is not excalidrawlib")
  if (typeof obj.version !== "number") return positionError(obj, "obj.version type is not number")
  if (!obj.libraryItems || !isLibraryItems(obj.libraryItems)) return positionError(obj, "The library array does not exist or is wrong")
  return true
}

async function readExcalidrawlibFile(filePath: string): Promise<ExportedLibraryData> {
  const content = await readFile(filePath, 'utf-8');
  const parsed = JSON.parse(content);

  if (!isExportedLibraryData(parsed)) {
    console.error({filePath, parsed})
    throw new Error(`Invalid excalidrawlib file: ${filePath}`);
  }

  return parsed;
}

async function updateExcalidrawlibFile(inputFilePath: string, outputFilePath: string): Promise<ExportedLibraryData | undefined> {
  if (!isExcalidrawlibFile(inputFilePath)) return undefined
  if (!isExcalidrawlibFile(outputFilePath)) return undefined

  const originalData = await readExcalidrawlibFile(outputFilePath);
  const inputData = await readExcalidrawlibFile(inputFilePath);
  const exportedLibraryData: ExportedLibraryData = {
    type: originalData.type,
    version: originalData.version,
    source: originalData.source,
    libraryItems: []
  }

  inputData.libraryItems.map(item => {
    if (item.status === 'unpublished' && isUniqueItem(originalData.libraryItems, item)) {
      exportedLibraryData.libraryItems = [
        ...exportedLibraryData.libraryItems,
        {...item}
      ]
    }
  })

  return exportedLibraryData;
}

async function saveUpdatedExcalidrawlib(data: ExportedLibraryData, filePath: string) {
  const jsonString = JSON.stringify(data, null, 2); // 缩进美化
  await writeFile(filePath, jsonString, 'utf-8');
  console.log(`✅ 更新完成，已保存到 ${filePath}`);
}

// 执行流程
const updated = await updateExcalidrawlibFile(inputFile, outputFile);
if (updated !== undefined) {
  saveUpdatedExcalidrawlib(updated, outputFile);
}