CommandLineObjectPicker.cs

// Copyright (c) The University of Dundee 2018-2019
// This file is part of the Research Data Management Platform (RDMP).
// RDMP is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
// RDMP is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along with RDMP. If not, see <https://www.gnu.org/licenses/>.

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using Rdmp.Core.CommandExecution;

namespace Rdmp.Core.CommandLine.Interactive.Picking;

/// <summary>
/// Parses arguments given along with the "cmd" command to rdmp.exe (<see cref="Rdmp.Core.CommandLine.Options.ExecuteCommandOptions"/>).  This
/// allows the user to launch certain commands (<see cref="Rdmp.Core.CommandExecution.BasicCommandExecution"/>) from the CLI.
/// </summary>
public class CommandLineObjectPicker
{
    public IReadOnlyCollection<CommandLineObjectPickerArgumentValue> Arguments { get; }

    public CommandLineObjectPickerArgumentValue this[int i] => Arguments.ElementAt(i);

    public int Length => Arguments.Count;

    private readonly HashSet<PickObjectBase> _pickers = new();

    /// <summary>
    /// Constructs a picker with all possible formats and immediately parse the provided <paramref name="args"/>
    /// </summary>
    /// <param name="args"></param>
    /// <param name="activator"></param>
    public CommandLineObjectPicker(IEnumerable<string> args,
        IBasicActivateItems activator)
    {
        _pickers.Add(new PickObjectByID(activator));
        _pickers.Add(new PickObjectByName(activator));
        _pickers.Add(new PickObjectByQuery(activator));
        _pickers.Add(new PickDatabase());
        _pickers.Add(new PickTable());
        _pickers.Add(new PickType(activator));
        Arguments = new ReadOnlyCollection<CommandLineObjectPickerArgumentValue>(args.Select(ParseValue).ToList());
    }

    /// <summary>
    /// Constructs a picker with only the passed format(s) (<paramref name="pickers"/>) and immediately parse the provided <paramref name="args"/>
    /// </summary>
    /// <param name="args"></param>
    /// <param name="pickers"></param>
    public CommandLineObjectPicker(string[] args, IEnumerable<PickObjectBase> pickers)
    {
        foreach (var p in pickers)
            _pickers.Add(p);

        Arguments = new ReadOnlyCollection<CommandLineObjectPickerArgumentValue>(args.Select(ParseValue).ToList());
    }

    private CommandLineObjectPickerArgumentValue ParseValue(string arg, int idx)
    {
        //find a picker that recognizes the format
        var pickers = _pickers.Where(p => p.IsMatch(arg, idx)).ToArray();

        if (pickers.Any())
            return pickers.First().Parse(arg, idx).Merge(pickers.Skip(1).Select(p => p.Parse(arg, idx)));

        //nobody recognized it, use the raw value (maybe it's just a regular string, int etc).  Delay hard typing it till we know
        //what constructor we are trying to match it to.
        return new CommandLineObjectPickerArgumentValue(arg, idx);
    }

    /// <summary>
    /// Returns true if the given <paramref name="idx"/> exists and is populated with a value of the expected <paramref name="paramType"/>
    /// </summary>
    /// <param name="idx"></param>
    /// <param name="paramType"></param>
    /// <returns></returns>
    public bool HasArgumentOfType(int idx, Type paramType) =>
        //if the index is greater than the number of arguments we have
        idx < Arguments.Count && Arguments.ElementAt(idx).HasValueOfType(paramType);
}