﻿/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

namespace Apache.Ignite.Linq
{
    using System;
    using System.Diagnostics;
    using System.Diagnostics.CodeAnalysis;
    using System.Linq;
    using System.Linq.Expressions;
    using Apache.Ignite.Core.Cache.Query;
    using Apache.Ignite.Core.Impl.Common;
    using Apache.Ignite.Linq.Impl;

    /// <summary>
    /// Delegate for compiled query with arbitrary number of arguments.
    /// </summary>
    /// <typeparam name="T">Result type.</typeparam>
    /// <param name="args">The arguments.</param>
    /// <returns>Query cursor.</returns>
    public delegate IQueryCursor<T> CompiledQueryFunc<T>(params object[] args);

    /// <summary>
    /// Represents a compiled cache query.
    /// </summary>
    public static class CompiledQuery
    {
        /// <summary>
        /// Creates a new delegate that represents the compiled cache query.
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static Func<IQueryCursor<T>> Compile<T>(Expression<Func<IQueryable<T>>> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var compiledQuery = GetCompiledQuery<T>(query);

            return () => compiledQuery(new object[0]);
        }

        /// <summary>
        /// Creates a new delegate that represents the compiled cache query with any number of arguments.
        /// <para />
        /// This method differs from other Compile methods in that it takes in <see cref="ICacheQueryable"/> directly,
        /// and returns a delegate that takes an array of parameters.
        /// It is up to the user to provide query arguments in correct order.
        /// <para />
        /// This method also imposes no restrictions on where the query comes from (in contrary to other methods).
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static CompiledQueryFunc<T> Compile<T>(IQueryable<T> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var cacheQueryable = query as ICacheQueryableInternal;

            if (cacheQueryable == null)
                throw GetInvalidQueryException(query);

            var compileQuery = cacheQueryable.CompileQuery<T>();

            // Special delegate is required to allow params[].
            return args => compileQuery(args);
        }

        /// <summary>
        /// Creates a new delegate that represents the compiled cache query.
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static Func<T1, IQueryCursor<T>> Compile<T, T1>(Expression<Func<T1, IQueryable<T>>> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var compiledQuery = GetCompiledQuery<T>(query);

            return x => compiledQuery(new object[] {x});
        }

        /// <summary>
        /// Creates a new delegate that represents the compiled cache query.
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static Func<T1, T2, IQueryCursor<T>> Compile<T, T1, T2>(Expression<Func<T1, T2, 
            IQueryable<T>>> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var compiledQuery = GetCompiledQuery<T>(query);

            return (x, y) => compiledQuery(new object[] {x, y});
        }

        /// <summary>
        /// Creates a new delegate that represents the compiled cache query.
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static Func<T1, T2, T3, IQueryCursor<T>> Compile<T, T1, T2, T3>(Expression<Func<T1, T2, T3,
            IQueryable<T>>> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var compiledQuery = GetCompiledQuery<T>(query);

            return (x, y, z) => compiledQuery(new object[] {x, y, z});
        }

        /// <summary>
        /// Creates a new delegate that represents the compiled cache query.
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static Func<T1, T2, T3, T4, IQueryCursor<T>> Compile<T, T1, T2, T3, T4>(Expression<Func<T1, T2, T3, T4,
            IQueryable<T>>> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var compiledQuery = GetCompiledQuery<T>(query);

            return (x, y, z, a) => compiledQuery(new object[] {x, y, z, a});
        }

        /// <summary>
        /// Creates a new delegate that represents the compiled cache query.
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static Func<T1, T2, T3, T4, T5, IQueryCursor<T>> Compile<T, T1, T2, T3, T4, T5>(
            Expression<Func<T1, T2, T3, T4, T5, IQueryable<T>>> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var compiledQuery = GetCompiledQuery<T>(query);

            return (x, y, z, a, b) => compiledQuery(new object[] {x, y, z, a, b});
        }

        /// <summary>
        /// Creates a new delegate that represents the compiled cache query.
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static Func<T1, T2, T3, T4, T5, T6, IQueryCursor<T>> Compile<T, T1, T2, T3, T4, T5, T6>(
            Expression<Func<T1, T2, T3, T4, T5, T6, IQueryable<T>>> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var compiledQuery = GetCompiledQuery<T>(query);

            return (x, y, z, a, b, c) => compiledQuery(new object[] {x, y, z, a, b, c});
        }

        /// <summary>
        /// Creates a new delegate that represents the compiled cache query.
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static Func<T1, T2, T3, T4, T5, T6, T7, IQueryCursor<T>> Compile<T, T1, T2, T3, T4, T5, T6, T7>(
            Expression<Func<T1, T2, T3, T4, T5, T6, T7, IQueryable<T>>> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var compiledQuery = GetCompiledQuery<T>(query);

            return (x, y, z, a, b, c, d) => compiledQuery(new object[] {x, y, z, a, b, c, d});
        }

        /// <summary>
        /// Creates a new delegate that represents the compiled cache query.
        /// </summary>
        /// <param name="query">The query to compile.</param>
        /// <returns>Delegate that represents the compiled cache query.</returns>
        [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", 
            Justification = "Invalid warning, validation is present.")]
        public static Func<T1, T2, T3, T4, T5, T6, T7, T8, IQueryCursor<T>> Compile<T, T1, T2, T3, T4, T5, T6, T7, T8>(
            Expression<Func<T1, T2, T3, T4, T5, T6, T7, T8, IQueryable<T>>> query)
        {
            IgniteArgumentCheck.NotNull(query, "query");

            var compiledQuery = GetCompiledQuery<T>(query);

            return (x, y, z, a, b, c, d, e) => compiledQuery(new object[] {x, y, z, a, b, c, d, e});
        }

        /// <summary>
        /// Gets the compiled query.
        /// </summary>
        private static Func<object[], IQueryCursor<T>> GetCompiledQuery<T>(LambdaExpression expression)
        {
            Debug.Assert(expression != null);
            
            // Get default parameter values.
            var paramValues = expression.Parameters
                .Select(x => x.Type)
                .Select(x => x.IsValueType ? Activator.CreateInstance(x) : null)
                .ToArray();

            var transformingxpressionVisitor = new JoinInnerSequenceParameterNotNullExpressionVisitor();
            var queryCaller = (LambdaExpression)transformingxpressionVisitor.Visit(expression);

            // Compile and invoke the delegate to obtain the cacheQueryable.
            var queryable = queryCaller.Compile().DynamicInvoke(paramValues);

            var cacheQueryable = queryable as ICacheQueryableInternal;

            if (cacheQueryable == null)
                throw GetInvalidQueryException(queryable);

            return cacheQueryable.CompileQuery<T>(expression);
        }

        /// <summary>
        /// Gets the invalid query exception.
        /// </summary>
        private static ArgumentException GetInvalidQueryException(object queryable)
        {
            return new ArgumentException(
                string.Format("{0} can only compile cache queries produced by AsCacheQueryable method. " +
                              "Provided query is not valid: '{1}'", typeof(CompiledQuery).FullName, queryable));
        }
    }
}