/**
 * @angular-modernizer/plugin-angular - Dependency Injection Migration Transformation Rule
 *
 * Transform rule that modernizes Angular dependency injection patterns.
 * This is part of the modernization to improve code maintainability and follow Angular best practices.
 *
 * Philosophy: "Thin Rule, Thick Orchestrator"
 * - The rule is a minimal wrapper
 * - All business logic lives in the orchestrator
 * - The rule handles the plugin protocol (TransformRule interface)
 */

import type {
  TransformRule,
  TransformContext,
  TransformResult,
} from '@angular-modernizer/plugin-system';
import type { PublicApi } from '@angular-modernizer/api';
import { DependencyInjectionMigrationOrchestrator } from '../orchestrators/dependency-injection-migration-orchestrator.js';

/**
 * Transform rule for modernizing Angular dependency injection patterns.
 *
 * @remarks
 * This rule implements the {@link TransformRule} interface and serves as the
 * bridge between the Angular Modernizer's plugin system and the dependency
 * injection migration orchestrator. It follows the "Thin Rule, Thick Orchestrator" pattern
 * where the rule handles protocol compliance while delegating all business logic
 * to the {@link DependencyInjectionMigrationOrchestrator}.
 *
 * ## What It Does
 *
 * The rule orchestrates the modernization of:
 * - **String-based injection tokens**: Converts `@Inject('TOKEN')` to proper `InjectionToken` usage
 * - **Deprecated injector patterns**: Updates old injector usage patterns
 * - **Provider configurations**: Modernizes provider syntax where applicable
 * - **Injection token imports**: Ensures proper imports for modern DI patterns
 *
 * ## Example Usage
 *
 * This rule is typically not used directly, but rather accessed through the
 * {@link AngularPlugin}:
 *
 * ```typescript
 * const plugin = new AngularPlugin();
 * const rules = plugin.getTransformRules();
 * const rule = rules.find(r => r.id === 'angular:dependency-injection-migration');
 * const result = await rule.transform(context);
 * ```
 *
 * ## Transformation Behavior
 *
 * **String-based Tokens**:
 * ```typescript
 * // Before
 * @Inject('API_URL') private apiUrl: string;
 *
 * // After
 * private apiUrl = inject(API_URL_TOKEN);
 * ```
 *
 * **Deprecated Injector Usage**:
 * ```typescript
 * // Before
 * const injector = ReflectiveInjector.resolveAndCreate([SomeService]);
 *
 * // After
 * const injector = Injector.create({ providers: [SomeService] });
 * ```
 *
 * @see {@link DependencyInjectionMigrationOrchestrator} for transformation logic
 * @see {@link TransformRule} for the interface contract
 * @see {@link AngularPlugin} for plugin integration
 *
 * @public
 */
export class DependencyInjectionMigrationRule implements TransformRule {
  /**
   * Unique rule identifier.
   * Format: "plugin-name:rule-name"
   */
  public readonly id = 'angular:dependency-injection-migration';

  /**
   * Human-readable rule name.
   */
  public readonly name = 'Dependency Injection Migration';

  /**
   * Rule description.
   */
  public readonly description =
    'Modernizes Angular dependency injection patterns to follow current best practices';

  /**
   * Rule category for grouping.
   */
  public readonly category = 'modernization';

  /**
   * Tags for filtering and search.
   */
  public readonly tags = [
    'angular',
    'dependency-injection',
    'inject',
    'tokens',
    'providers',
    'modernization',
    'refactoring',
  ];

  /**
   * The orchestrator that performs the actual transformation.
   */
  private readonly orchestrator =
    new DependencyInjectionMigrationOrchestrator();

  /**
   * Transform a source file by modernizing dependency injection patterns.
   *
   * @remarks
   * This method implements the {@link TransformRule.transform} contract.
   * It delegates to the {@link DependencyInjectionMigrationOrchestrator} for the actual
   * transformation work, then packages the result into a {@link TransformResult}.
   *
   * The method:
   * 1. Captures the file's initial state
   * 2. Invokes the orchestrator to perform the modernization
   * 3. Detects whether the file was modified
   * 4. Returns a standardized {@link TransformResult}
   *
   * ## Return Value
   *
   * The transform result includes:
   * - `modified`: Whether the file was changed
   * - `message`: A human-readable summary
   * - `filePath`: The path to the transformed file
   * - `ruleId`: This rule's identifier
   *
   * @param context - Transform context with file, project, and API access
   *
   * @returns Promise resolving to the transformation result
   *
   * @example
   * ```typescript
   * const rule = new DependencyInjectionMigrationRule();
   * const result = await rule.transform(context);
   *
   * if (result.modified) {
   *   console.info(`Modernized DI patterns: ${result.filePath}`);
   * }
   * ```
   *
   * @public
   */
  async transform(
    context: TransformContext<PublicApi>,
  ): Promise<TransformResult> {
    const { sourceFile, filePath } = context;

    // Check if this transformation type is requested
    const pluginConfig = context.config[
      '@angular-modernizer/plugin-angular'
    ] as Record<string, unknown> | undefined;
    if (
      pluginConfig?.['transformationType'] !== 'dependency-injection-migration'
    ) {
      return {
        ruleId: this.id,
        modified: false,
        message: 'Transformation type not applicable',
        filePath,
      };
    }

    // Capture initial state to detect modifications
    const initialText = sourceFile.getFullText();

    // Run the orchestrator
    this.orchestrator.run(context);

    // Detect if the file was modified
    const modified = sourceFile.getFullText() !== initialText;

    // Return the result
    return {
      ruleId: this.id,
      modified,
      message: modified
        ? `Successfully modernized dependency injection patterns`
        : `No dependency injection patterns found to modernize`,
      filePath,
    };
  }
}