using System;
using System.IO;
using Core.Common.IO.Exceptions;
using Ringtoets.HydraRing.Data;
using Ringtoets.HydraRing.IO.HydraulicBoundaryDatabaseContext;
using Ringtoets.HydraRing.IO.HydraulicLocationConfigurationDatabaseContext;

namespace Ringtoets.HydraRing.IO
{
    /// <summary>
    /// This class defines helper methods for obtaining meta data from hyraulic boundary databases.
    /// </summary>
    public static class HydraulicDatabaseHelper
    {
        /// <summary>
        /// Attempts to connect to the <paramref name="filePath"/> as if it is a Hydraulic Boundary Locations 
        /// database with a Hydraulic Location Configurations database next to it.
        /// </summary>
        /// <param name="filePath">The path of the Hydraulic Boundary Locations database file.</param>
        /// <returns>A <see cref="string"/> describing the problem when trying to connect to the <paramref name="filePath"/> 
        /// or <c>null</c> if a connection could be correctly made.</returns>
        public static string ValidatePathForCalculation(string filePath)
        {
            try
            {
                using (var db = new HydraulicBoundarySqLiteDatabaseReader(filePath))
                {
                    db.GetVersion();
                }
                string hlcdFilePath = Path.Combine(Path.GetDirectoryName(filePath), "hlcd.sqlite");
                new HydraulicLocationConfigurationSqLiteDatabaseReader(hlcdFilePath).Dispose();
            }
            catch (CriticalFileReadException e)
            {
                return e.Message;
            }
            return null;
        }

        /// <summary>
        /// Returns the version from the database pointed at by the <paramref name="filePath"/>.
        /// </summary>
        /// <param name="filePath">The location of the database.</param>
        /// <returns>The version from the database as a <see cref="string"/>.</returns>
        /// <exception cref="CriticalFileReadException">Thrown when no connection with the hydraulic 
        /// boundary database could be created.</exception>
        private static string GetVersion(string filePath)
        {
            using (var db = new HydraulicBoundarySqLiteDatabaseReader(filePath))
            {
                return db.GetVersion();
            }
        }

        /// <summary>
        /// Checks whether the version of a <see cref="HydraulicBoundaryDatabase"/> matches the version
        /// of a database at the given <see cref="pathToDatabase"/>.
        /// </summary>
        /// <param name="database">The database to compare the version of.</param>
        /// <param name="pathToDatabase">The path to the database to compare the version of.</param>
        /// <returns><c>true</c> if <paramref name="database"/> is of the given <paramref name="version"/>,
        /// <c>false</c> otherwise.</returns>
        /// <exception cref="CriticalFileReadException">Thrown when no connection with the hydraulic 
        /// boundary database could be created using <paramref name="pathToDatabase"/>.</exception>
        /// <exception cref="ArgumentNullException">Thrown when:
        /// <list type="bullet">
        /// <item><paramref name="database"/> is <c>null</c></item>
        /// <item><paramref name="pathToDatabase"/> is <c>null</c></item>
        /// </list></exception>
        public static bool HaveEqualVersion(HydraulicBoundaryDatabase database, string pathToDatabase)
        {
            if (database == null)
            {
                throw new ArgumentNullException("database");
            }
            if (pathToDatabase == null)
            {
                throw new ArgumentNullException("pathToDatabase");
            }
            return database.Version == GetVersion(pathToDatabase);
        }
    }
}