import path from 'node:path';
import { readJson, writeJson } from '../../utils/fs.js';
import type { WorkspaceModuleView, WorkspacePackageJson } from '../../config/workspaceManifest.js';

export interface SsgViewMetadataOptions {
  readonly workspaceRoot: string;
  readonly pageName: string;
}

export async function ensureSsgViewMetadataForPage(options: SsgViewMetadataOptions): Promise<void> {
  const pkgPath = path.join(options.workspaceRoot, 'package.json');
  const pkg = (await readJson<WorkspacePackageJson>(pkgPath)) ?? {};
  const workspaceMode = pkg.webstir?.mode;
  const isSsgWorkspace = typeof workspaceMode === 'string' && workspaceMode.toLowerCase() === 'ssg';
  if (isSsgWorkspace) {
    return;
  }

  const webstir = pkg.webstir ?? {};
  const moduleConfig = webstir.moduleManifest ?? {};
  const existingViews = Array.isArray(moduleConfig.views) ? [...moduleConfig.views] : [];

  const pageName = options.pageName;
  const isHome = pageName === 'home';
  const viewName = `${capitalize(pageName)}View`;
  const viewPath = isHome ? '/' : `/${pageName}`;

  const existingIndex = existingViews.findIndex(
    (view) => view?.name === viewName || view?.path === viewPath,
  );
  const existing = existingIndex >= 0 ? (existingViews[existingIndex] ?? {}) : {};
  const nextView: WorkspaceModuleView = {
    ...existing,
    name: viewName,
    path: viewPath,
    renderMode: 'ssg',
    staticPaths: [viewPath],
  };

  if (existingIndex >= 0) {
    existingViews[existingIndex] = nextView;
  } else {
    existingViews.push(nextView);
  }

  const nextPkg: WorkspacePackageJson = {
    ...pkg,
    webstir: {
      ...webstir,
      moduleManifest: {
        ...moduleConfig,
        views: existingViews,
      },
    },
  };

  await writeJson(pkgPath, nextPkg);
}

function capitalize(value: string): string {
  if (!value) {
    return value;
  }
  return value.charAt(0).toUpperCase() + value.slice(1);
}