using System;
using System.Collections.Generic;
using System.Linq;

namespace HanvonF710XAttendanceService
{
    internal static class MachineUserDeleteSyncTests
    {
        public static int RunAll()
        {
            int failed = 0;
            failed += Run("651 IDs split into 33 batches of 20", Test651IdsSplitInto33Batches);
            failed += Run("exactly 20 IDs is one batch", TestExactly20IdsOneBatch);
            failed += Run("fewer than 20 IDs is one batch", TestFewerThan20IdsOneBatch);
            failed += Run("empty deletion list", TestEmptyDeletionList);
            failed += Run("successful batch marks DB deleted", TestSuccessfulBatchMarksDeleted);
            failed += Run("failed batch remains pending", TestFailedBatchRemainsPending);
            return failed;
        }

        private static int Run(string name, Func<bool> test)
        {
            try
            {
                if (!test())
                {
                    Console.WriteLine("FAIL: " + name);
                    return 1;
                }

                Console.WriteLine("PASS: " + name);
                return 0;
            }
            catch (Exception ex)
            {
                Console.WriteLine("FAIL: " + name + " err=" + ex.Message);
                return 1;
            }
        }

        private static bool Test651IdsSplitInto33Batches()
        {
            var ids = BuildIds(651);
            var batches = MachineUserDeleteBatcher.SplitIntoBatches(ids, 20);
            return batches.Count == 33
                && batches.Take(32).All(b => b.Count == 20)
                && batches[32].Count == 11
                && MachineUserDeleteBatcher.CountBatches(651, 20) == 33;
        }

        private static bool TestExactly20IdsOneBatch()
        {
            var ids = BuildIds(20);
            var batches = MachineUserDeleteBatcher.SplitIntoBatches(ids, 20);
            return batches.Count == 1 && batches[0].Count == 20;
        }

        private static bool TestFewerThan20IdsOneBatch()
        {
            var ids = BuildIds(7);
            var batches = MachineUserDeleteBatcher.SplitIntoBatches(ids, 20);
            return batches.Count == 1 && batches[0].Count == 7;
        }

        private static bool TestEmptyDeletionList()
        {
            var batches = MachineUserDeleteBatcher.SplitIntoBatches(new List<string>(), 20);
            var result = MachineUserDeleteSync.Execute(
                "105",
                "192.168.90.223",
                new List<MachineUserDeleteItem>(),
                20,
                null,
                null,
                null);
            return batches.Count == 0
                && result.TotalPending == 0
                && result.SuccessCount == 0
                && result.FailedCount == 0;
        }

        private static bool TestSuccessfulBatchMarksDeleted()
        {
            var pending = new List<MachineUserDeleteItem>
            {
                new MachineUserDeleteItem("1001", "1001"),
                new MachineUserDeleteItem("1002", "1002"),
                new MachineUserDeleteItem("1003", "1003")
            };
            var marked = new List<string>();
            var logs = new List<string>();

            var result = MachineUserDeleteSync.Execute(
                "105",
                "192.168.90.223",
                pending,
                20,
                (IReadOnlyList<string> ids, out string error) =>
                {
                    error = null;
                    return ids.Count == 3;
                },
                serial => marked.Add(serial),
                logs.Add);

            return result.TotalPending == 3
                && result.SuccessCount == 3
                && result.FailedCount == 0
                && marked.Count == 3
                && marked.Contains("1001")
                && marked.Contains("1002")
                && marked.Contains("1003")
                && logs.Any(l => l.Contains("result=SUCCESS"));
        }

        private static bool TestFailedBatchRemainsPending()
        {
            var pending = BuildDeleteItems(40);
            var marked = new List<string>();
            int callCount = 0;

            var result = MachineUserDeleteSync.Execute(
                "105",
                "192.168.90.223",
                pending,
                20,
                (IReadOnlyList<string> ids, out string error) =>
                {
                    callCount++;
                    if (callCount == 2)
                    {
                        error = "The operation has timed out";
                        return false;
                    }

                    error = null;
                    return true;
                },
                serial => marked.Add(serial),
                _ => { });

            return result.TotalPending == 40
                && result.SuccessCount == 20
                && result.FailedCount == 20
                && marked.Count == 20
                && !marked.Contains("21")
                && marked.Contains("1")
                && marked.Contains("20");
        }

        private static List<string> BuildIds(int count)
        {
            var ids = new List<string>(count);
            for (int i = 1; i <= count; i++)
            {
                ids.Add(i.ToString());
            }

            return ids;
        }

        private static List<MachineUserDeleteItem> BuildDeleteItems(int count)
        {
            var items = new List<MachineUserDeleteItem>(count);
            for (int i = 1; i <= count; i++)
            {
                items.Add(new MachineUserDeleteItem(i.ToString(), i.ToString()));
            }

            return items;
        }
    }
}