import { watch, onMounted, reactive } from 'vue';

export type ImportedLib = {
  versions: string[];
  selectedVersion: string;
  libTypes: string;
};

export type XOCashLibs = {
  '@xocash/stack': ImportedLib;
  '@xocash/primitives': ImportedLib;
};

const xocashLibs = reactive<XOCashLibs>({
  '@xocash/stack': {
    versions: [],
    selectedVersion: '',
    libTypes: '',
  },
  '@xocash/primitives': {
    versions: [],
    selectedVersion: '',
    libTypes: '',
  },
});

export const useXOCashLibs = (): XOCashLibs => {
  // Get versions from npm registry
  const getVersions = async (): Promise<string[]> => {
    const response = await fetch('https://registry.npmjs.org/@xocash/stack');

    const data = await response.json();

    const versions = Object.keys(data.versions);

    return versions;
  };

  const getTypes = async (packageName: string, version: string) => {
    const response = await fetch(
      `https://cdn.jsdelivr.net/npm/${packageName}@${version}/dist/types-bundled.d.ts`,
    );

    const content = await response.text();

    return content;
  };

  // Update the types file when the selected version changes.
  watch(
    () => xocashLibs['@xocash/stack'].selectedVersion,
    async (newVersion) => {
      const stackTypes = await getTypes('@xocash/stack', newVersion);
      const primitivesTypes = await getTypes('@xocash/primitives', newVersion);

      // Only set the types file if the selected version has not been changed while fetching the types.
      if (xocashLibs['@xocash/stack'].selectedVersion === newVersion) {
        xocashLibs['@xocash/stack'].libTypes = stackTypes;
        xocashLibs['@xocash/primitives'].libTypes = primitivesTypes;
      }
    },
  );

  // Fetch the versions and set the selected version when the component is mounted.
  onMounted(async () => {
    xocashLibs['@xocash/stack'].versions = await getVersions();

    // Only update the selected version if it is not already set.
    if (!xocashLibs['@xocash/stack'].selectedVersion) {
      xocashLibs['@xocash/stack'].selectedVersion =
        xocashLibs['@xocash/stack'].versions[
          xocashLibs['@xocash/stack'].versions.length - 1
        ];
    }
  });

  return xocashLibs;
};