const fs = require('fs')
const path = require("path");
const { execSync } = require("child_process");

const getSlugFromPath = (filePath) => {
	// Normalize the path - remove leading ./ if present
	const normalizedPath = filePath.startsWith('./') ? filePath.slice(2) : filePath;
	
	// For top-level files: recipes/foo.md -> slug is "foo"
	// For nested folders: recipes/bar/v1.md -> slug is "bar"
	const parts = normalizedPath.split(path.sep);
	
	// parts[0] should be 'recipes', parts[1] is the key part
	if (parts.length >= 2 && parts[0] === 'recipes') {
		const secondPart = parts[1];
		// If it's a .md file at the top level (recipes/foo.md), strip the extension
		if (secondPart.endsWith('.md')) {
			return path.basename(secondPart, '.md');
		}
		// Otherwise it's a folder name (recipes/bar/v1.md -> bar)
		return secondPart;
	}
	return path.basename(filePath, '.md');
}

const getTitleFromSlug = (slug) => {
	return slug
		.split('-')
		.map(word => word.charAt(0).toUpperCase() + word.slice(1))
		.join(' ');
}

const getGitCreatedTime = (filePath) => {
	try {
		const result = execSync(
			`git log --diff-filter=A --follow --format=%aI -- "${filePath}" | tail -1`,
			{ encoding: "utf-8", stdio: ["pipe", "pipe", "pipe"] }
		).trim();
		if (result) {
			return new Date(result).getTime();
		}
	} catch (e) {
		// Git command failed, fall through to filesystem
	}
	return null;
}

const getFileCreatedTime = (filePath) => {
	// Try git first for accurate cross-system creation time
	const gitTime = getGitCreatedTime(filePath);
	if (gitTime) {
		return gitTime;
	}
	
	// Fall back to filesystem for untracked files
	try {
		const stats = fs.statSync(filePath);
		const time = stats.birthtime ?? stats.mtime;
		return time.getTime();
	} catch (e) {
		return Date.now();
	}
}

const getVersion = (filePath) => {
	const dirName = path.dirname(filePath)

	// Top-level files (directly in recipes/) always have version 0
	if (dirName === 'recipes' || dirName === './recipes') {
		return 0
	}	

	const files = fs.readdirSync(dirName).filter(f => f.endsWith('.md'))

	const filesWithDates = files
		.map((file) => {
			const fullPath = path.join(dirName, file);
			return {
				file: fullPath,
				createdAt: getFileCreatedTime(fullPath),
			}
		})
		.sort((a, b) => a.createdAt - b.createdAt) // oldest first (version 0)

	const normalizedFilePath = filePath.startsWith('./') ? filePath.slice(2) : filePath;
	const version = filesWithDates.findIndex(({ file }) => {
		const normalizedFile = file.startsWith('./') ? file.slice(2) : file;
		return normalizedFile === normalizedFilePath;
	});
	
	return version === -1 ? 0 : version;
}

const isNewestVersion = (filePath) => {
	const dirName = path.dirname(filePath)

	// Top-level files are always the "newest" (only version)
	if (dirName === 'recipes' || dirName === './recipes') {
		return true
	}

	const files = fs.readdirSync(dirName).filter(f => f.endsWith('.md'))
	
	const filesWithDates = files
		.map((file) => {
			const fullPath = path.join(dirName, file);
			return {
				file: fullPath,
				createdAt: getFileCreatedTime(fullPath),
			}
		})
		.sort((a, b) => b.createdAt - a.createdAt) // newest first

	const normalizedFilePath = filePath.startsWith('./') ? filePath.slice(2) : filePath;
	const newestFile = filesWithDates[0]?.file;
	const normalizedNewest = newestFile?.startsWith('./') ? newestFile.slice(2) : newestFile;
	
	return normalizedFilePath === normalizedNewest;
}

module.exports = {
	layout: "recipe.njk",
	tags: ["recipe"],
	eleventyComputed: {
		recipeSlug: (data) => {
			return getSlugFromPath(data.page.inputPath);
		},
		title: (data) => {
			if (data.title && data.title !== data.page.fileSlug) {
				return data.title;
			}
			const slug = getSlugFromPath(data.page.inputPath);
			return getTitleFromSlug(slug);
		},
		recipeVersion: (data) => {
			return getVersion(data.page.inputPath);
		},
		isNewestVersion: (data) => {
			// Draft recipes are never considered "newest" for redirect purposes
			if (data.draft === true) {
				return false;
			}
			return isNewestVersion(data.page.inputPath);
		},
		isDraft: (data) => {
			return data.draft === true;
		},
		permalink: (data) => {
			const slug = getSlugFromPath(data.page.inputPath);
			const version = getVersion(data.page.inputPath);
			return `/recipe/${slug}/${version}/`;
		}
	}
}