import { For, memo, SourceDirectoryContext, useContext } from "@alloy-js/core";
import { basename } from "pathe";

import { getSourceDirectoryData } from "../source-directory-data.js";
import type { TSModuleScope } from "../symbols/index.js";
import { ExportStatement } from "./ExportStatement.js";
import { SourceFile } from "./SourceFile.js";

export interface BarrelFileProps {
  /**
   * The name of the source file
   */
  path?: string;

  /**
   * Whether the source file is exported out of the package. When true, this
   * source file with its source file relative to the project root. Otherwise,
   * it will be exported with the specified path.
   */
  export?: boolean | string;
}

/**
 * Creates a source file which re-exports the exports in other files and nested
 * barrel files in the source directory its placed in.
 *
 * @remarks
 *
 * This component must be placed directly inside a {@link @alloy-js/core#SourceDirectory}
 * component. It will only discover nested barrel files directly within nested
 * source directories.
 *
 * @example
 *
 * Creating a barrel file which exports the two other source files in the same directory
 *
 * ```tsx
 * <Output>
 *   <SourceDirectory path="src">
 *     <SourceFile path="one.ts" />
 *     <SourceFile path="two.ts" />
 *     <BarrelFile />
 *   </SourceDirectory>
 * </Output>
 * ```
 *
 * The barrel file will contain the following contents:
 *
 * ```ts
 * export * from "./one.js";
 * export * from "./two.js";
 * ```
 *
 *
 * @see {@link @alloy-js/core#SourceDirectory}
 * @see {@link SourceFile}
 */
export function BarrelFile(props: BarrelFileProps) {
  const path = props.path ?? "index.ts";
  const directory = useContext(SourceDirectoryContext)!;
  const sdData = getSourceDirectoryData(directory);

  const exports = memo(() => {
    const subdirs = directory.contents.filter(
      (c) => !(c as any).filetype,
    ) as SourceDirectoryContext[];

    const nestedBarrels: TSModuleScope[] = [];
    for (const subdir of subdirs) {
      const nestedSdData = getSourceDirectoryData(subdir);
      const nestedBarrel = Array.from(nestedSdData.modules).find(
        (m) => basename(m.name) === "index.ts",
      );
      if (nestedBarrel) {
        nestedBarrels.push(nestedBarrel);
      }
    }

    const sourceFiles = Array.from(sdData.modules).filter(
      (m) => basename(m.name) !== "index.ts",
    );

    return [...sourceFiles, ...nestedBarrels];
  });

  return (
    <SourceFile path={path} export={props.export}>
      <For each={exports}>{(mod) => <ExportStatement star from={mod} />}</For>
    </SourceFile>
  );
}