using System;

using System.Data.Entity;

using System.Data.Entity.ModelConfiguration.Conventions;

using SQLite.CodeFirst.Convention;

using System.IO;

namespace SQLite.CodeFirst

{

/// <summary>

/// An basic implementation of the <see cref="IDatabaseInitializer{TContext}"/> interface.

/// This class provides common logic which can be used when writing an Sqlite-Initializer.

/// The logic provided is:

/// 1. Remove/Add specific Conventions

/// 2. Get the path to the database file

/// 3. Create a new SQLite-Database from the model (Code First)

/// 4. Seed data to the new created database

/// The following implementations are provided: <see cref="T:SQLite.CodeFirst.SqliteCreateDatabaseIfNotExists`1"/>, <see cref="T:SQlite.CodeFirst.SqliteDropCreateDatabaseAlways`1"/>.

/// </summary>

/// <typeparam name="TContext">The type of the context.</typeparam>

public abstract class SqliteInitializerBase<TContext> : IDatabaseInitializer<TContext>

where TContext : DbContext

{

private readonly DbModelBuilder modelBuilder;

protected SqliteInitializerBase(DbModelBuilder modelBuilder)

{

if (modelBuilder == null)

{

throw new ArgumentNullException("modelBuilder");

}

this.modelBuilder = modelBuilder;

// This convention will crash the SQLite Provider before "InitializeDatabase" gets called.

// See https://github.com/msallin/SQLiteCodeFirst/issues/7 for details.

modelBuilder.Conventions.Remove<TimestampAttributeConvention>();

// By default there is a 'ForeignKeyIndexConvention' but it can be removed.

// And there is no "Contains" and no way to enumerate the ConventionsCollection.

// So a try/catch will do the job.

try

{

// Place the own ForeinKeyIndexConvention right after the original.

// The own convention will rename the automatically created indicies by using the correct scheme.

modelBuilder.Conventions.AddAfter<ForeignKeyIndexConvention>(new SqliteForeignKeyIndexConvention());

}

catch (InvalidOperationException exception)

{

// Ignore it.

}

}

/// <summary>

/// Initialize the database for the given context.

/// Generates the SQLite-DDL from the model and executs it against the database.

/// After that the <see cref="Seed"/> method is executed.

/// All actions are be executed in transactions.

/// </summary>

/// <param name="context">The context. </param>

public virtual void InitializeDatabase(TContext context)

{

var model = modelBuilder.Build(context.Database.Connection);

var dbFile = GetDatabasePathFromContext(context);

var dbFileInfo = new FileInfo(dbFile);

dbFileInfo.Directory.Create();

using (var transaction = context.Database.BeginTransaction())

{

try

{

var sqliteDatabaseCreator = new SqliteDatabaseCreator(context.Database, model);

sqliteDatabaseCreator.Create();

transaction.Commit();

}

catch (Exception)

{

transaction.Rollback();

throw;

}

}

using (var transaction = context.Database.BeginTransaction())

{

try

{

Seed(context);

context.SaveChanges();

transaction.Commit();

}

catch (Exception)

{

transaction.Rollback();

throw;

}

}

}

/// <summary>

/// Is executed right after the initialization <seealso cref="InitializeDatabase"/>.

/// Use this method to seed data into the empty database.

/// </summary>

/// <param name="context">The context.</param>

protected virtual void Seed(TContext context) { }

/// <summary>

/// Gets the database path file path from a <see cref="TContext"/>.

/// </summary>

/// <param name="context">The context to get the database file path from.</param>

/// <returns>The full path to the SQLite database file.</returns>

protected string GetDatabasePathFromContext(TContext context)

{

return SqliteConnectionStringParser.GetDataSource(context.Database.Connection.ConnectionString);

}

}

}