import { GitHubClient, GitHubFile } from './github-client';
import { MergeStrategyRegistry } from './merge-strategy-registry';
import { FilePatternMergeStrategy, MergeStrategyConfig, TemplateProcessingResult, TemplateRepository } from './types';

export class GitHubTemplateManager {
	private client: GitHubClient;
	private mergeRegistry: MergeStrategyRegistry;

	constructor(client: GitHubClient) {
		this.client = client;
		this.mergeRegistry = new MergeStrategyRegistry();
	}

	async processTemplate(
		template: TemplateRepository,
		targetOwner: string,
		targetRepo: string,
		excludePatterns: string[] = [],
		mergeStrategy: 'overwrite' | 'merge' | 'skip' | MergeStrategyConfig = 'merge',
		mergeStrategies: FilePatternMergeStrategy[] = [],
		plugins: string[] = []
	): Promise<TemplateProcessingResult> {
		const result: TemplateProcessingResult = {
			success: true,
			template,
			filesProcessed: 0,
			errors: [],
		};

		try {
			// Load plugins
			for (const plugin of plugins) {
				await this.mergeRegistry.loadPlugin(plugin);
			}

			// Get template files from GitHub
			const templateFiles = await this.client.getTemplateFiles(template);

			// Filter out excluded files
			const filteredFiles = this.filterFiles(templateFiles, excludePatterns);

			// Process files based on merge strategy
			await this.processFiles(filteredFiles, targetOwner, targetRepo, mergeStrategy, mergeStrategies, result);
		} catch (error) {
			result.success = false;
			result.errors.push(`Template processing failed: ${error}`);
		}

		return result;
	}

	private filterFiles(files: GitHubFile[], excludePatterns: string[]): GitHubFile[] {
		return files.filter((file) => {
			// Skip directories in processing
			if (file.type === 'dir') {
				return false;
			}

			// Apply exclude patterns
			return !this.shouldExclude(file.path, excludePatterns);
		});
	}

	private shouldExclude(filePath: string, excludePatterns: string[]): boolean {
		return excludePatterns.some((pattern) => {
			const regex = new RegExp(pattern.replace(/\*\*/g, '.*').replace(/\*/g, '[^/]*'));
			return regex.test(filePath);
		});
	}

	private async processFiles(files: GitHubFile[], targetOwner: string, targetRepo: string, mergeStrategy: 'overwrite' | 'merge' | 'skip' | MergeStrategyConfig, mergeStrategies: FilePatternMergeStrategy[], result: TemplateProcessingResult): Promise<void> {
		const branch = `boots-strapper-update-${Date.now()}`;

		try {
			// Create a new branch for the template updates
			await this.client.createBranch(targetOwner, targetRepo, branch);

			for (const file of files) {
				try {
					// Determine merge strategy for this file
					const defaultMergeStrategy = typeof mergeStrategy === 'string' ? { type: mergeStrategy as 'overwrite' | 'merge' | 'skip' } : mergeStrategy;

					const fileStrategy = await this.mergeRegistry.resolveStrategyForFile(file.path, mergeStrategies, defaultMergeStrategy);

					const shouldProcess = await this.shouldProcessFile(targetOwner, targetRepo, file.path, fileStrategy.name);

					if (shouldProcess) {
						let content = file.content;

						// Get existing content if file exists
						let existingContent = '';
						try {
							const existingFiles = await this.client.getRepositoryContents(targetOwner, targetRepo, file.path);
							const existingFile = existingFiles.find((f) => f.path === file.path && f.type === 'file');
							existingContent = existingFile?.content || '';
						} catch (error) {
							// File doesn't exist, which is fine
						}

						// Apply merge strategy
						if (existingContent) {
							const mergeResult = await fileStrategy.merge({
								filePath: file.path,
								templateName: result.template.name,
								existingContent,
								newContent: file.content,
							});

							if (mergeResult.success) {
								content = mergeResult.content;

								// Track warnings and conflicts
								if (mergeResult.warnings) {
									result.errors.push(...mergeResult.warnings.map((w) => `Warning: ${w}`));
								}
								if (mergeResult.conflicts) {
									result.errors.push(...mergeResult.conflicts.map((c) => `Conflict: ${c}`));
								}
							} else {
								result.errors.push(`Merge failed for ${file.path}, using new content`);
							}
						}

						await this.client.createOrUpdateFile(targetOwner, targetRepo, file.path, content, `Update ${file.path} from template ${result.template.name} using ${fileStrategy.name} strategy`, branch);

						result.filesProcessed++;
					}
				} catch (error) {
					result.errors.push(`Failed to process file ${file.path}: ${error}`);
				}
			}

			// Create a pull request with the changes
			if (result.filesProcessed > 0) {
				const prNumber = await this.client.createPullRequest(targetOwner, targetRepo, `Update repository from template: ${result.template.name}`, this.generatePullRequestBody(result.template, result), branch, 'main');

				result.pullRequestNumber = prNumber;
			}
		} catch (error) {
			result.success = false;
			result.errors.push(`Branch creation or PR failed: ${error}`);
		}
	}

	private async shouldProcessFile(owner: string, repo: string, filePath: string, strategyName: string): Promise<boolean> {
		if (strategyName === 'overwrite') {
			return true;
		}

		try {
			// Check if file exists
			await this.client.getRepositoryContents(owner, repo, filePath);

			// File exists
			if (strategyName === 'skip') {
				return false;
			}

			// All other strategies process existing files
			return true;
		} catch (error) {
			// File doesn't exist, so we can create it
			return true;
		}
	}

	async cleanup(): Promise<void> {
		await this.mergeRegistry.cleanup();
	}

	private generatePullRequestBody(template: TemplateRepository, result: TemplateProcessingResult): string {
		return `
## Template Update

This pull request updates the repository with changes from the template: **${template.name}**

**Template Details:**
- Repository: ${template.url}
- Branch: ${template.branch || 'main'}
${template.subDirectory ? `- Subdirectory: ${template.subDirectory}` : ''}

**Changes:**
- ${result.filesProcessed} files processed
${result.errors.length > 0 ? `- ${result.errors.length} errors encountered` : ''}

**Files Modified:**
<!-- This will be populated with the actual file list -->

---

*This PR was automatically generated by [RepoWeaver](https://github.com/apps/repoweaver)*
    `.trim();
	}
}