'use strict';

var Manage = module.exports;
var doctor = {};

var sfs = require('safe-replace').create({ tmp: 'tmp', bak: 'bak' });
var promisify = require('util').promisify;
var fs = require('fs');
var readFile = promisify(fs.readFile);
var statFile = promisify(fs.stat);
var chmodFile = promisify(fs.chmod);
var homedir = require('os').homedir();
var path = require('path');
var mkdirp = promisify(require('@root/mkdirp'));

// NOTE
// this is over-complicated to account for people
// doing weird things, and this just being a file system
// and wanting to be fairly sure it works and produces
// meaningful errors

// IMPORTANT
// For your use case you'll probably find a better example
// in greenlock-manager-test:
//
//    npm install --save greenlock-manager-test
//    npx greenlock-manager-init
//

Manage.create = function(CONF) {
	if (!CONF) {
		CONF = {};
	}
	if (!CONF.configFile) {
		CONF.configFile = '~/.config/greenlock/manager.json';
		console.info('Greenlock Manager Config File: ' + CONF.configFile);
	}
	CONF.configFile = CONF.configFile.replace('~/', homedir + '/');

	var manage = {};

	manage._txPromise = Promise.resolve();

	// Note: all of these top-level methods are effectively mutexed
	// You cannot call them from each other or they will deadlock

	manage.defaults = manage.config = async function(conf) {
		manage._txPromise = manage._txPromise.then(async function() {
			var config = await Manage._getLatest(manage, CONF);

			// act as a getter
			if (!conf) {
				conf = JSON.parse(JSON.stringify(config.defaults));
				return conf;
			}

			// act as a setter
			Object.keys(conf).forEach(function(k) {
				// challenges are either both overwritten, or not set
				// this is as it should be
				config.defaults[k] = conf[k];
			});

			return manage._save(config);
		});

		return manage._txPromise;
	};

	manage.set = async function(args) {
		manage._txPromise = manage._txPromise.then(async function() {
			var config = await Manage._getLatest(manage, CONF);

			manage._merge(config, config.sites[args.subject], args);

			await manage._save(config);
			return JSON.parse(JSON.stringify(config.sites[args.subject]));
		});

		return manage._txPromise;
	};

	manage.get = async function(args) {
		manage._txPromise = manage._txPromise.then(async function() {
			var config = await Manage._getLatest(manage, CONF);
			var site;
			Object.keys(config.sites).some(function(k) {
				// if subject is specified, don't return anything else
				var _site = config.sites[k];

				// altnames, servername, and wildname all get rolled into one
				return _site.altnames.some(function(altname) {
					if ([args.servername, args.wildname].includes(altname)) {
						site = _site;
					}
				});
			});

			if (site && !site.deletedAt) {
				return doctor.site(config.sites, site.subject);
			}
			return null;
		});

		return manage._txPromise;
	};

	manage._merge = function(config, current, args) {
		if (!current || current.deletedAt) {
			current = config.sites[args.subject] = {
				subject: args.subject,
				altnames: [],
				renewAt: 1
			};
		}

		current.renewAt = parseInt(args.renewAt || current.renewAt, 10) || 1;
		var oldAlts;
		var newAlts;
		if (args.altnames) {
			// copy as to not disturb order, which matters
			oldAlts = current.altnames.slice(0).sort();
			newAlts = args.altnames.slice(0).sort();

			if (newAlts.join() !== oldAlts.join()) {
				// this will cause immediate renewal
				args.renewAt = 1;
				current.altnames = args.altnames.slice(0);
			}
		}
		Object.keys(args).forEach(function(k) {
			if ('altnames' === k) {
				return;
			}
			current[k] = args[k];
		});
	};

	// no transaction promise here because it calls set
	manage.find = async function(args) {
		var ours = await _find(args);
		if (!CONF.find) {
			return ours;
		}

		// if the user has an overlay find function we'll do a diff
		// between the managed state and the overlay, and choose
		// what was found.
		var theirs = await CONF.find(args);
		var config = await Manage._getLatest(manage, CONF);
		return _mergeFind(config, ours, theirs);
	};

	function _find(args) {
		manage._txPromise = manage._txPromise.then(async function() {
			var config = await Manage._getLatest(manage, CONF);
			// i.e. find certs more than 30 days old
			//args.issuedBefore = Date.now() - 30 * 24 * 60 * 60 * 1000;
			// i.e. find certs more that will expire in less than 45 days
			//args.expiresBefore = Date.now() + 45 * 24 * 60 * 60 * 1000;
			var issuedBefore = args.issuedBefore || Infinity;
			var expiresBefore = args.expiresBefore || Infinity; //Date.now() + 21 * 24 * 60 * 60 * 1000;
			var renewBefore = args.renewBefore || Infinity; //Date.now() + 21 * 24 * 60 * 60 * 1000;

			// if there's anything to match, only return matches
			// if there's nothing to match, return everything
			var nameKeys = ['subject', 'altnames'];
			var matchAll = !nameKeys.some(function(k) {
				return k in args;
			});

			var querynames = (args.altnames || []).slice(0);

			var sites = Object.keys(config.sites)
				.filter(function(subject) {
					var site = config.sites[subject];
					if (site.deletedAt) {
						return false;
					}
					if (site.expiresAt >= expiresBefore) {
						return false;
					}
					if (site.issuedAt >= issuedBefore) {
						return false;
					}
					if (site.renewAt >= renewBefore) {
						return false;
					}

					// after attribute filtering, before cert filtering
					if (matchAll) {
						return true;
					}

					// if subject is specified, don't return anything else
					if (site.subject === args.subject) {
						return true;
					}

					// altnames, servername, and wildname all get rolled into one
					return site.altnames.some(function(altname) {
						return querynames.includes(altname);
					});
				})
				.map(function(name) {
					return doctor.site(config.sites, name);
				});

			return sites;
		});

		return manage._txPromise;
	}

	function _mergeFind(config, ours, theirs) {
		theirs.forEach(function(_newer) {
			var hasCurrent = ours.some(function(_older) {
				if (_newer.subject !== _older.subject) {
					return false;
				}

				// BE SURE TO SET THIS UNDEFINED AFTERWARDS
				_older._exists = true;

				manage._merge(config, _older, _newer);
				_newer = config.sites[_older.subject];

				// handled the (only) match
				return true;
			});
			if (hasCurrent) {
				manage._merge(config, null, _newer);
			}
		});

		// delete the things that are gone
		ours.forEach(function(_older) {
			if (!_older._exists) {
				delete config.sites[_older.subject];
			}
			_older._exists = undefined;
		});

		manage._txPromise = manage._txPromise.then(async function() {
			// kinda redundant to pull again, but whatever...
			var config = await Manage._getLatest(manage, CONF);
			await manage._save(config);
			// everything was either added, updated, or not different
			// hence, this is everything
			var copy = JSON.parse(JSON.stringify(config.sites));
			return Object.keys(copy).map(function(k) {
				return copy[k];
			});
		});

		return manage._txPromise;
	}

	manage.remove = function(args) {
		if (!args.subject) {
			throw new Error('should have a subject for sites to remove');
		}
		manage._txPromise = manage._txPromise.then(async function() {
			var config = await Manage._getLatest(manage, CONF);
			var site = config.sites[args.subject];
			if (!site || site.deletedAt) {
				return null;
			}
			site.deletedAt = Date.now();
			await manage._save(config);
			return JSON.parse(JSON.stringify(site));
		});
		return manage._txPromise;
	};

	manage._config = {};
	// (wrong type #1) specifically the wrong type (null)
	manage._lastStat = { size: null, mtimeMs: null };

	manage._save = async function(config) {
		await mkdirp(path.dirname(CONF.configFile));
		// pretty-print the config file
		var data = JSON.parse(JSON.stringify(config));
		var sites = data.sites || {};
		data.sites = Object.keys(sites).map(function(k) {
			return sites[k];
		});
		await sfs.writeFileAsync(
			CONF.configFile,
			JSON.stringify(data, null, 2),
			'utf8'
		);

		// this file may contain secrets, so keep it safe
		return chmodFile(CONF.configFile, parseInt('0600', 8))
			.catch(function() {
				/*ignore for Windows */
			})
			.then(async function() {
				var stat = await statFile(CONF.configFile);
				manage._lastStat.size = stat.size;
				manage._lastStat.mtimeMs = stat.mtimeMs;
			});
	};

	manage.init = async function(deps) {
		// even though we don't need it
		manage.request = deps.request;
		return null;
	};

	return manage;
};

Manage._getLatest = function(MNG, CONF) {
	return statFile(CONF.configFile)
		.catch(async function(err) {
			if ('ENOENT' !== err.code) {
				err.context = 'manager_read';
				throw err;
			}
			await MNG._save(doctor.config());
			// (wrong type #2) specifically the wrong type (bool)
			return { size: false, mtimeMs: false };
		})
		.then(async function(stat) {
			if (
				stat.size === MNG._lastStat.size &&
				stat.mtimeMs === MNG._lastStat.mtimeMs
			) {
				return MNG._config;
			}
			var data = await readFile(CONF.configFile, 'utf8');
			MNG._lastStat = stat;
			MNG._config = JSON.parse(data);
			return doctor.config(MNG._config);
		});
};

// users muck up config files, so we try to handle it gracefully.
doctor.config = function(config) {
	if (!config) {
		config = {};
	}
	if (!config.defaults) {
		config.defaults = {};
	}

	doctor.sites(config);

	Object.keys(config).forEach(function(key) {
		// .greenlockrc and greenlock.json shall merge as one
		// and be called greenlock.json because calling it
		// .greenlockrc seems to rub people the wrong way
		if (['manager', 'defaults', 'routes', 'sites'].includes(key)) {
			return;
		}
		config.defaults[key] = config[key];
		delete config[key];
	});

	doctor.challenges(config.defaults);

	return config;
};
doctor.sites = function(config) {
	var sites = config.sites;
	if (!sites) {
		sites = {};
	}
	if (Array.isArray(config.sites)) {
		sites = {};
		config.sites.forEach(function(site) {
			sites[site.subject] = site;
		});
	}
	Object.keys(sites).forEach(function(k) {
		doctor.site(sites, k);
	});
	config.sites = sites;
};
doctor.site = function(sconfs, subject) {
	var site = sconfs[subject];
	if (!site) {
		delete sconfs[subject];
		site = {};
	}

	if ('string' !== typeof site.subject) {
		console.warn('warning: deleted malformed site from config file:');
		console.warn(JSON.stringify(site));
		delete sconfs[subject];
		site.subject = 'greenlock-error.example.com';
	}
	if (!Array.isArray(site.altnames)) {
		site.altnames = [site.subject];
	}
	if (!site.renewAt) {
		site.renewAt = 1;
	}

	return site;
};

doctor.challenges = function(defaults) {
	var challenges = defaults.challenges;
	if (!challenges) {
		challenges = {};
	}
	if (Array.isArray(defaults.challenges)) {
		defaults.challenges.forEach(function(challenge) {
			var typ = doctor.challengeType(challenge);
			challenges[typ] = challenge;
		});
	}
	Object.keys(challenges).forEach(function(k) {
		doctor.challenge(challenges, k);
	});
	defaults.challenges = challenges;
	if (!Object.keys(defaults.challenges).length) {
		delete defaults.challenges;
	}
};
doctor.challengeType = function(challenge) {
	var typ = challenge.type;
	if (!typ) {
		if (/\bhttp-01\b/.test(challenge.module)) {
			typ = 'http-01';
		} else if (/\bdns-01\b/.test(challenge.module)) {
			typ = 'dns-01';
		} else if (/\btls-alpn-01\b/.test(challenge.module)) {
			typ = 'tls-alpn-01';
		} else {
			typ = 'error-01';
		}
	}
	delete challenge.type;
	return typ;
};
doctor.challenge = function(chconfs, typ) {
	var ch = chconfs[typ];
	if (!ch) {
		delete chconfs[typ];
	}
	return;
};