use std::{
	fs::{self, File},
	path::{Path, PathBuf},
};

use serde_json::Value;
use walkdir::WalkDir;

const META_SERVER: &str = "https://meta.fabricmc.net/";
const MAVEN_SERVER: &str = "https://maven.fabricmc.net/";

fn query_meta_json(path: &str) -> Value {
	ureq::get(&format!("{META_SERVER}{path}")).call().unwrap().into_json().unwrap()
}

fn download_maven(url: &str, path: &Path) {
	fs::create_dir_all(path.parent().unwrap()).unwrap();
	let mut file = File::create(path).unwrap();
	if url.starts_with(MAVEN_SERVER) {
		crate::download::download(&format!("{url}"), &mut file).unwrap();
	} else {
		crate::download::download(&format!("{META_SERVER}{url}"), &mut file).unwrap();
	}
}

fn library_from_json(json: &Value) -> Option<(String, String, String)> {
	let name = json.get("name")?.as_str()?;
	let url = json.get("url")?.as_str()?;

	// Split "group:artifact:version"
	let parts: Vec<&str> = name.splitn(3, ':').collect();
	if parts.len() != 3 {
		return None;
	}

	let group = parts[0].replace('.', "/");
	let artifact = parts[1];
	let version = parts[2];

	// Build remote URL (like Java's getURL)
	let jar_name = format!("{artifact}-{version}.jar");
	let remote_path = format!("{}/{}/{}/{jar_name}", group, artifact, version);
	let full_url = format!("{}{}", url, remote_path);

	// Build local path (like Java's getPath)
	let group_fs = parts[0].replace('.', &std::path::MAIN_SEPARATOR.to_string());
	let local_path = PathBuf::from(group_fs)
		.join(artifact)
		.join(version)
		.join(jar_name)
		.to_string_lossy()
		.replace(' ', "_");

	Some((name.to_string(), full_url, local_path))
}

pub fn install_fabric(minecraft_path: &Path, minecraft_version: &str, loader_version: &str) -> Result<(), crate::error::Error> {
	let profile_name = format!("{minecraft_version}-fabric");
	let versions_dir = minecraft_path.join("versions");
	let profile_dir = versions_dir.join(&profile_name);
	let profile_json = profile_dir.join(format!("{profile_name}.json"));
	let libs_dir = minecraft_path.join("libraries");

	let mut libs = WalkDir::new(&libs_dir)
		.into_iter()
		.filter_map(|e| e.ok())
		.filter(|e| e.file_type().is_file());

	let mut json = query_meta_json(&format!("v2/versions/loader/{minecraft_version}/{loader_version}/profile/json"));

	*json.get_mut("id").unwrap() = Value::String(profile_name.clone());

	fs::create_dir_all(&profile_dir).unwrap();

	fs::write(&profile_json, json.to_string()).unwrap();

	fs::copy(
		versions_dir.join(minecraft_version).join(format!("{minecraft_version}.jar")),
		profile_dir.join(profile_name + ".jar"),
	)
	.unwrap();

	for lib_json in json.get("libraries").unwrap().as_array().unwrap() {
		if let Some((name, url, path)) = library_from_json(lib_json) {
			let lib_file = libs_dir.join(path);
			let lib_id = lib_file.parent().unwrap().parent().unwrap(); // Removes the version/lib.jar
			if !libs.any(|e| e.path().starts_with(lib_id)) {
				println!("Installing library '{name}'");
				download_maven(&url, &lib_file);
			} else {
				println!("library '{name}' Already exists, skipping");
			}
		} else {
			eprintln!("Failed to get json from {lib_json}")
		}
	}

	Ok(())
}