/*
BunyMuny parses the CSV output of various bank statement listings and converts it to something more human readable with nice visualisations.
Copyright (C) 2020 Lynnear Software

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.If not, see <https: //www.gnu.org/licenses/>.
*/

using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.CommandLine.DragonFruit;
using System.Linq;
using CsvHelper;

namespace BunyMuny {
	internal class Program {
		/// <summary>
		/// BunyMuny parses the CSV output of various bank statement listings and converts it to something more human readable with nice visualisations.
		/// </summary>
		/// <param name="file">The CSV file to read</param>
		/// <param name="ruleFile">The CSV file to use for rules when parsing statement descriptions</param>
		/// <returns></returns>
		private static int Main(string file = "test.csv", string ruleFile = "rules.csv") {
			var bank = Bank.Other;
			var statements = new List<Statement>();
			List<Rule> rules;

			using (var ruleStreamReader = new StreamReader(ruleFile)) {
				using var ruleCsv = new CsvReader(ruleStreamReader,CultureInfo.InvariantCulture);
				rules = ruleCsv.GetRecords<Rule>().ToList();
			}

			using var sr = new StreamReader(file);
			using var csv = new CsvReader(sr, CultureInfo.InvariantCulture);

			csv.Read();
			csv.ReadHeader();

			// get the first line of the CSV file (the header) as a string
			var header = csv.Parser.Context.RawRecord.Trim();
			switch (header) {
				case null:
					Console.WriteLine("File is empty 0uo");
					return 1;
				case "Date,Description,Debits and credits,Balance":
					bank = Bank.ME;
					break;
				case "Whatever NAB uses I guess":
					bank = Bank.NAB;
					break;
				default:
					Console.WriteLine($"Unknown header: [{header}]");
					break;
			}

			while (csv.Read()) {
				switch (bank) {
					case Bank.ME:
						var value = double.Parse(csv.GetField("Debits and credits").TrimStart().Replace("$", ""));
						var (category, description) = MatchAgainstRules(rules, csv.GetField("Description"));

						statements.Add(new Statement() {
							Date = DateTime.ParseExact(csv.GetField("Date"), "dd/MM/yyyy", CultureInfo.InvariantCulture),
							OriginalDescription = csv.GetField("Description"),
							Description = description,
							Category = category,
							Value = value
						});
						break;

					case Bank.NAB:
						Console.WriteLine("Unimplemented");
						return 1;

					case Bank.Other:
						Console.WriteLine("Unknown bank!");
						return 1;

					default:
						Console.WriteLine(":(");
						return 1;
				}
			}

			foreach (var statement in statements.
				// Where(s => s.Category != null).
				OrderBy(s => s.Date)) {
				Console.WriteLine(statement);
			}

			return 0;
		}

		private static (string Category, string Description) MatchAgainstRules(List<Rule> rules, string value) {
			foreach (var rule in rules) {
				if (rule.Check(value)) {
					return (rule.Category, rule.Description);
				}
			}

			return (null, null);
		}
	}
}