#!/usr/bin/env nodejs


function string_coin(
	template,
	arguments_
)
{
	let result = template;
	Object.entries(arguments_).forEach(
		([key, value]) => {
			result = result.replace(new RegExp("{{" + key + "}}", "g"), value);
		}
	);
	return result;
}


function borg_init(
	repository_directory,
	{
		"encryption": encryption = "none",
	} = {
	}
)
{
	return string_coin(
		"borg init --encryption={{encryption}} {{repository_directory}}\n",
		{
			"repository_directory": repository_directory,
			"encryption": encryption,
		}
	);
}


function borg_create(
	repository_directory,
	archive_name,
	directories,
	{
		"compression": compression = "none",
	} = {
	}
)
{
	return string_coin(
		"borg create --compression={{compression}} {{repository_directory}}::{{archive_name}} {{directories}}\n",
		{
			"repository_directory": repository_directory,
			"archive_name": archive_name,
			"compression": compression,
			"directories": directories.join(" "),
		}
	)
}


function borg_prune(
	repository_directory,
	age,
	{
		"keep_weekly": keep_weekly = null,
		"keep_yearly": keep_yearly = null,
	} = {
	}
)
{
	return string_coin(
		"borg prune --keep-within=2w{{macro_keep_weekly}}{{macro_keep_yearly}} {{repository_directory}}\n",
		{
			"repository_directory": repository_directory,
			"keep_within": age,
			"macro_keep_weekly": ((keep_weekly === null) ? "" : string_coin(" --keep-weekly={{x}}", {"x": keep_weekly.toFixed(0)})),
			"macro_keep_yearly": ((keep_yearly === null) ? "" : string_coin(" --keep-yearly={{x}}", {"x": keep_yearly.toFixed(0)})),
		}
	)
}


function get_conf(
)
{
	const _fs = require("fs");
	const conf = JSON.parse(_fs.readFileSync("conf.json"));
	return conf;
}


function get_stamp(
)
{
	const date = (new Date(Date.now()));
	return string_coin(
		"{{year}}{{month}}{{day}}",
		{
			"year": date.getFullYear().toFixed(0).padStart(4, "0"),
			"month": (date.getMonth()+1).toFixed(0).padStart(2, "0"),
			"day": date.getDate().toFixed(0).padStart(2, "0"),
		}
	);
}


function get_repository_directory(
	conf
)
{
	return conf.target.data.repository;
}


function init(
	conf
)
{
	const repository_directory = get_repository_directory(conf);
	if (false) {
		process.stdout.write(
			string_coin(
				"mkdir --parents {{repository_directory}}\n",
				{
					"repository_directory": repository_directory,
				}
			)
		);
	}
	process.stdout.write(
		borg_init(
			repository_directory,
			{
				"encryption": "none",
			}
		)
	);
}


function run(
	conf,
	stamp
)
{
	const repository_directory = get_repository_directory(conf);
	conf.concerns.forEach(
		concern => {
			process.stdout.write(
				string_coin(
					"## {{name}}\n",
					{
						"name": concern.name,
					}
				)
			);
			process.stdout.write(
				borg_create(
					repository_directory,
					string_coin(
						"{{concern_name}}-{{stamp}}",
						{
							"concern_name": concern.name,
							"stamp": stamp,
						}
					),
					[concern.source_directory],
					{
						"compression": conf.target.data.compression,
					}
				)
			);
			process.stdout.write(
				borg_prune(
					repository_directory,
					"2w",
					{
						"keep_weekly": 7,
						"keep_yearly": 2,
					}
				)
			);
			process.stdout.write(
				"\n"
			);
		}
	);
}


function main(
	args
)
{
	// args
	const action = (args.shift() ?? "run");
	
	// exec
	switch (action) {
		case "init": {
			const conf = get_conf();
			init(conf);
			break;
		}
		case "run": {
			const conf = get_conf();
			const stamp = get_stamp();
			run(conf, stamp);
			break;
		}
		default: {
			throw (new Error("unhandled action: " + action));
			break;
		}
	}
}


main(process.argv.slice(2));