using BirthdayBot.Data;
using Newtonsoft.Json.Linq;
using Npgsql;
using System;
using System.IO;
using System.Reflection;
using System.Text.RegularExpressions;

namespace BirthdayBot;

/// <summary>
/// Loads and holds configuration values.
/// </summary>
class Configuration {
    public string BotToken { get; }
    public string LogWebhook { get; }
    public string? DBotsToken { get; }

    public const string ShardLenConfKey = "ShardRange";
    public int ShardStart { get; }
    public int ShardAmount { get; }

    public int ShardTotal { get; }

    public bool QuitOnFails { get; }

    public Configuration() {
        // Looks for settings.json in the executable directory.
        var confPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
        confPath += Path.DirectorySeparatorChar + "settings.json";

        if (!File.Exists(confPath)) {
            throw new Exception("Settings file not found."
                + " Create a file in the executable directory named 'settings.json'.");
        }

        var jc = JObject.Parse(File.ReadAllText(confPath));

        BotToken = jc[nameof(BotToken)]?.Value<string>();
        if (string.IsNullOrWhiteSpace(BotToken))
            throw new Exception($"'{nameof(BotToken)}' must be specified.");

        LogWebhook = jc[nameof(LogWebhook)]?.Value<string>();
        if (string.IsNullOrWhiteSpace(LogWebhook))
            throw new Exception($"'{nameof(LogWebhook)}' must be specified.");

        var dbj = jc[nameof(DBotsToken)];
        if (dbj != null) {
            DBotsToken = dbj.Value<string>();
        } else {
            DBotsToken = null;
        }

        var sqlhost = jc["SqlHost"]?.Value<string>() ?? "localhost"; // Default to localhost
        var sqluser = jc["SqlUsername"]?.Value<string>();
        var sqlpass = jc["SqlPassword"]?.Value<string>();
        if (string.IsNullOrWhiteSpace(sqluser) || string.IsNullOrWhiteSpace(sqlpass))
            throw new Exception("'SqlUsername', 'SqlPassword' must be specified.");
        var csb = new NpgsqlConnectionStringBuilder() {
            Host = sqlhost,
            Username = sqluser,
            Password = sqlpass
        };
        var sqldb = jc["SqlDatabase"]?.Value<string>();
        if (sqldb != null) csb.Database = sqldb; // Optional database setting
        Database.DBConnectionString = csb.ToString();

        int? sc = jc[nameof(ShardTotal)]?.Value<int>();
        if (!sc.HasValue) ShardTotal = 1;
        else {
            ShardTotal = sc.Value;
            if (ShardTotal <= 0) {
                throw new Exception($"'{nameof(ShardTotal)}' must be a positive integer.");
            }
        }

        string srVal = jc[ShardLenConfKey]?.Value<string>();
        if (!string.IsNullOrWhiteSpace(srVal)) {
            Regex srPicker = new(@"(?<low>\d{1,2})[-,]{1}(?<high>\d{1,2})");
            var m = srPicker.Match(srVal);
            if (m.Success) {
                ShardStart = int.Parse(m.Groups["low"].Value);
                int high = int.Parse(m.Groups["high"].Value);
                ShardAmount = high - (ShardStart - 1);
            } else {
                throw new Exception($"Shard range not properly formatted in '{ShardLenConfKey}'.");
            }
        } else {
            // Default: this instance handles all shards from ShardTotal
            ShardStart = 0;
            ShardAmount = ShardTotal;
        }

        QuitOnFails = jc[nameof(QuitOnFails)]?.Value<bool>() ?? false;
    }
}