import type { Compiler, Compilation, Chunk, Module } from 'webpack';

/**
 * This plugin removes eager modules from the runtime.
 * @class RemoveEagerModulesFromRuntimePlugin
 */
class RemoveEagerModulesFromRuntimePlugin {
  private container: string | undefined;
  private debug: boolean;
  private modulesToProcess: Set<Module>;

  /**
   * Creates an instance of RemoveEagerModulesFromRuntimePlugin.
   * @param {Object} options - The options for the plugin.
   * @param {string} options.container - The container to remove modules from.
   * @param {boolean} options.debug - Whether to log debug information.
   */
  constructor(options: { container?: string; debug?: boolean }) {
    this.container = options.container;
    this.debug = options.debug || false;
    this.modulesToProcess = new Set<Module>();
  }

  /**
   * Applies the plugin to the compiler.
   * @param {Compiler} compiler - The webpack compiler.
   */
  apply(compiler: Compiler) {
    if (!this.container) {
      console.warn(
        '[nextjs-mf]:',
        'RemoveEagerModulesFromRuntimePlugin container is not defined:',
        this.container,
      );
      return;
    }

    compiler.hooks.thisCompilation.tap(
      'RemoveEagerModulesFromRuntimePlugin',
      (compilation: Compilation) => {
        compilation.hooks.optimizeChunkModules.tap(
          'RemoveEagerModulesFromRuntimePlugin',
          (chunks: Iterable<Chunk>, modules: Iterable<Module>) => {
            for (const chunk of chunks) {
              if (chunk.hasRuntime() && chunk.name === this.container) {
                this.processModules(compilation, chunk, modules);
              }
            }
          },
        );
      },
    );
  }

  /**
   * Processes the modules in the chunk.
   * @param {Compilation} compilation - The webpack compilation.
   * @param {Chunk} chunk - The chunk to process.
   * @param {Iterable<Module>} modules - The modules in the chunk.
   */
  private processModules(
    compilation: Compilation,
    chunk: Chunk,
    modules: Iterable<Module>,
  ) {
    for (const module of modules) {
      if (!compilation.chunkGraph.isModuleInChunk(module, chunk)) {
        continue;
      }

      if (module.constructor.name === 'NormalModule') {
        this.modulesToProcess.add(module);
      }
    }

    this.removeModules(compilation, chunk);
  }

  /**
   * Removes the modules from the chunk.
   * @param {Compilation} compilation - The webpack compilation.
   * @param {Chunk} chunk - The chunk to remove modules from.
   */
  private removeModules(compilation: Compilation, chunk: Chunk) {
    for (const moduleToRemove of this.modulesToProcess) {
      if (this.debug) {
        console.log('removing', moduleToRemove.constructor.name);
      }

      if (compilation.chunkGraph.isModuleInChunk(moduleToRemove, chunk)) {
        compilation.chunkGraph.disconnectChunkAndModule(chunk, moduleToRemove);
      }
    }
  }
}

export default RemoveEagerModulesFromRuntimePlugin;