// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

using System.Collections.ObjectModel;
using System.Management.Automation.Runspaces;
using System.Text;

namespace System.Management.Automation
{
 /// <summary>
 /// Provides information about a function that is stored in session state.
 /// </summary>
 public class FunctionInfo : CommandInfo, IScriptCommandInfo
 {
 #region ctor

 /// <summary>
 /// Creates an instance of the FunctionInfo class with the specified name and ScriptBlock.
 /// </summary>
 /// <param name="name">
 /// The name of the function.
 /// </param>
 /// <param name="function">
 /// The ScriptBlock for the function
 /// </param>
 /// <param name="context">
 /// The execution context for the function.
 /// </param>
 /// <exception cref="ArgumentNullException">
 /// If <paramref name="function"/> is null.
 /// </exception>
 internal FunctionInfo(string name, ScriptBlock function, ExecutionContext context) : this(name, function, context, null)
 {
 }

 /// <summary>
 /// Creates an instance of the FunctionInfo class with the specified name and ScriptBlock.
 /// </summary>
 /// <param name="name">
 /// The name of the function.
 /// </param>
 /// <param name="function">
 /// The ScriptBlock for the function
 /// </param>
 /// <param name="context">
 /// The execution context for the function.
 /// </param>
 /// <param name="helpFile">
 /// The name of the help file associated with the function.
 /// </param>
 /// <exception cref="ArgumentNullException">
 /// If <paramref name="function"/> is null.
 /// </exception>
 internal FunctionInfo(string name, ScriptBlock function, ExecutionContext context, string helpFile) : base(name, CommandTypes.Function, context)
 {
 if (function == null)
 {
 throw PSTraceSource.NewArgumentNullException("function");
 }

 _scriptBlock = function;

 CmdletInfo.SplitCmdletName(name, out _verb, out _noun);

 this.Module = function.Module;
 _helpFile = helpFile;
 }

 /// <summary>
 /// Creates an instance of the FunctionInfo class with the specified name and ScriptBlock.
 /// </summary>
 /// <param name="name">
 /// The name of the function.
 /// </param>
 /// <param name="function">
 /// The ScriptBlock for the function
 /// </param>
 /// <param name="options">
 /// The options to set on the function. Note, Constant can only be set at creation time.
 /// </param>
 /// <param name="context">
 /// The execution context for the function.
 /// </param>
 /// <exception cref="ArgumentNullException">
 /// If <paramref name="function"/> is null.
 /// </exception>
 internal FunctionInfo(string name, ScriptBlock function, ScopedItemOptions options, ExecutionContext context) : this(name, function, options, context, null)
 {
 }

 /// <summary>
 /// Creates an instance of the FunctionInfo class with the specified name and ScriptBlock.
 /// </summary>
 /// <param name="name">
 /// The name of the function.
 /// </param>
 /// <param name="function">
 /// The ScriptBlock for the function
 /// </param>
 /// <param name="options">
 /// The options to set on the function. Note, Constant can only be set at creation time.
 /// </param>
 /// <param name="context">
 /// The execution context for the function.
 /// </param>
 /// <param name="helpFile">
 /// The name of the help file associated with the function.
 /// </param>
 /// <exception cref="ArgumentNullException">
 /// If <paramref name="function"/> is null.
 /// </exception>
 internal FunctionInfo(string name, ScriptBlock function, ScopedItemOptions options, ExecutionContext context, string helpFile)
 : this(name, function, context, helpFile)
 {
 _options = options;
 }

 /// <summary>
 /// This is a copy constructor, used primarily for get-command.
 /// </summary>
 internal FunctionInfo(FunctionInfo other)
 : base(other)
 {
 CopyFieldsFromOther(other);
 }

 private void CopyFieldsFromOther(FunctionInfo other)
 {
 _verb = other._verb;
 _noun = other._noun;
 _scriptBlock = other._scriptBlock;
 _description = other._description;
 _options = other._options;
 _helpFile = other._helpFile;
 }

 /// <summary>
 /// This is a copy constructor, used primarily for get-command.
 /// </summary>
 internal FunctionInfo(string name, FunctionInfo other)
 : base(name, other)
 {
 CopyFieldsFromOther(other);

 // Get the verb and noun from the name
 CmdletInfo.SplitCmdletName(name, out _verb, out _noun);
 }

 /// <summary>
 /// Create a copy of commandInfo for GetCommandCommand so that we can generate parameter
 /// sets based on an argument list (so we can get the dynamic parameters.)
 /// </summary>
 internal override CommandInfo CreateGetCommandCopy(object[] arguments)
 {
 FunctionInfo copy = new FunctionInfo(this) { IsGetCommandCopy = true, Arguments = arguments };
 return copy;
 }

 #endregion ctor

 internal override HelpCategory HelpCategory
 {
 get { return HelpCategory.Function; }
 }

 /// <summary>
 /// Gets the ScriptBlock which is the implementation of the function.
 /// </summary>
 public ScriptBlock ScriptBlock
 {
 get { return _scriptBlock; }
 }

 private ScriptBlock _scriptBlock;

 /// <summary>
 /// Updates a function.
 /// </summary>
 /// <param name="newFunction">
 /// The script block that the function should represent.
 /// </param>
 /// <param name="force">
 /// If true, the script block will be applied even if the filter is ReadOnly.
 /// </param>
 /// <param name="options">
 /// Any options to set on the new function, null if none.
 /// </param>
 /// <exception cref="ArgumentNullException">
 /// If <paramref name="newFunction"/> is null.
 /// </exception>
 internal void Update(ScriptBlock newFunction, bool force, ScopedItemOptions options)
 {
 Update(newFunction, force, options, null);
 this.DefiningLanguageMode = newFunction.LanguageMode;
 }

 /// <summary/>
 protected internal virtual void Update(FunctionInfo newFunction, bool force, ScopedItemOptions options, string helpFile)
 {
 Update(newFunction.ScriptBlock, force, options, helpFile);
 }

 /// <summary>
 /// Updates a function.
 /// </summary>
 /// <param name="newFunction">
 /// The script block that the function should represent.
 /// </param>
 /// <param name="force">
 /// If true, the script block will be applied even if the filter is ReadOnly.
 /// </param>
 /// <param name="options">
 /// Any options to set on the new function, null if none.
 /// </param>
 /// <param name="helpFile">
 /// The helpfile for this function.
 /// </param>
 /// <exception cref="ArgumentNullException">
 /// If <paramref name="newFunction"/> is null.
 /// </exception>
 internal void Update(ScriptBlock newFunction, bool force, ScopedItemOptions options, string helpFile)
 {
 if (newFunction == null)
 {
 throw PSTraceSource.NewArgumentNullException("function");
 }

 if ((_options & ScopedItemOptions.Constant) != 0)
 {
 SessionStateUnauthorizedAccessException e =
 new SessionStateUnauthorizedAccessException(
 Name,
 SessionStateCategory.Function,
 "FunctionIsConstant",
 SessionStateStrings.FunctionIsConstant);

 throw e;
 }

 if (!force && (_options & ScopedItemOptions.ReadOnly) != 0)
 {
 SessionStateUnauthorizedAccessException e =
 new SessionStateUnauthorizedAccessException(
 Name,
 SessionStateCategory.Function,
 "FunctionIsReadOnly",
 SessionStateStrings.FunctionIsReadOnly);

 throw e;
 }

 _scriptBlock = newFunction;

 this.Module = newFunction.Module;
 _commandMetadata = null;
 this._parameterSets = null;
 this.ExternalCommandMetadata = null;

 if (options != ScopedItemOptions.Unspecified)
 {
 this.Options = options;
 }

 _helpFile = helpFile;
 }

 /// <summary>
 /// Returns <c>true</c> if this function uses cmdlet binding mode for its parameters; otherwise returns <c>false</c>.
 /// </summary>
 public bool CmdletBinding
 {
 get
 {
 return this.ScriptBlock.UsesCmdletBinding;
 }
 }

 /// <summary>
 /// Gets the name of the default parameter set.
 /// Returns <c>null</c> if this function doesn't use cmdlet parameter binding or if the default parameter set wasn't specified.
 /// </summary>
 public string DefaultParameterSet
 {
 get
 {
 return this.CmdletBinding ? this.CommandMetadata.DefaultParameterSetName : null;
 }
 }

 /// <summary>
 /// Gets the definition of the function which is the
 /// ToString() of the ScriptBlock that implements the function.
 /// </summary>
 public override string Definition { get { return _scriptBlock.ToString(); } }

 /// <summary>
 /// Gets or sets the scope options for the function.
 /// </summary>
 /// <exception cref="SessionStateUnauthorizedAccessException">
 /// If the trying to set a function that is constant or
 /// if the value trying to be set is ScopedItemOptions.Constant
 /// </exception>
 public ScopedItemOptions Options
 {
 get
 {
 return CopiedCommand == null ? _options : ((FunctionInfo)CopiedCommand).Options;
 }

 set
 {
 if (CopiedCommand == null)
 {
 // Check to see if the function is constant, if so
 // throw an exception because the options cannot be changed.

 if ((_options & ScopedItemOptions.Constant) != 0)
 {
 SessionStateUnauthorizedAccessException e =
 new SessionStateUnauthorizedAccessException(
 Name,
 SessionStateCategory.Function,
 "FunctionIsConstant",
 SessionStateStrings.FunctionIsConstant);

 throw e;
 }

 // Now check to see if the caller is trying to set
 // the options to constant. This is only allowed at
 // variable creation

 if ((value & ScopedItemOptions.Constant) != 0)
 {
 // user is trying to set the function to constant after
 // creating the function. Do not allow this (as per spec).

 SessionStateUnauthorizedAccessException e =
 new SessionStateUnauthorizedAccessException(
 Name,
 SessionStateCategory.Function,
 "FunctionCannotBeMadeConstant",
 SessionStateStrings.FunctionCannotBeMadeConstant);

 throw e;
 }

 // Ensure we are not trying to remove the AllScope option

 if ((value & ScopedItemOptions.AllScope) == 0 &&
 (_options & ScopedItemOptions.AllScope) != 0)
 {
 SessionStateUnauthorizedAccessException e =
 new SessionStateUnauthorizedAccessException(
 this.Name,
 SessionStateCategory.Function,
 "FunctionAllScopeOptionCannotBeRemoved",
 SessionStateStrings.FunctionAllScopeOptionCannotBeRemoved);

 throw e;
 }

 _options = value;
 }
 else
 {
 ((FunctionInfo)CopiedCommand).Options = value;
 }
 }
 }

 private ScopedItemOptions _options = ScopedItemOptions.None;

 /// <summary>
 /// Gets or sets the description associated with the function.
 /// </summary>
 public string Description
 {
 get
 {
 return CopiedCommand == null ? _description : ((FunctionInfo)CopiedCommand).Description;
 }

 set
 {
 if (CopiedCommand == null)
 {
 _description = value;
 }
 else
 {
 ((FunctionInfo)CopiedCommand).Description = value;
 }
 }
 }

 private string _description = null;

 /// <summary>
 /// Gets the verb of the function.
 /// </summary>
 public string Verb
 {
 get
 {
 return _verb;
 }
 }

 private string _verb = string.Empty;

 /// <summary>
 /// Gets the noun of the function.
 /// </summary>
 public string Noun
 {
 get
 {
 return _noun;
 }
 }

 private string _noun = string.Empty;

 /// <summary>
 /// Gets the help file path for the function.
 /// </summary>
 public string HelpFile
 {
 get
 {
 return _helpFile;
 }

 internal set
 {
 _helpFile = value;
 }
 }

 private string _helpFile = string.Empty;

 /// <summary>
 /// Returns the syntax of a command.
 /// </summary>
 internal override string Syntax
 {
 get
 {
 StringBuilder synopsis = new StringBuilder();

 foreach (CommandParameterSetInfo parameterSet in ParameterSets)
 {
 synopsis.AppendLine();
 synopsis.AppendLine(
 string.Format(
 Globalization.CultureInfo.CurrentCulture,
 "{0} {1}",
 Name,
 parameterSet.ToString()));
 }

 return synopsis.ToString();
 }
 }

 /// <summary>
 /// True if the command has dynamic parameters, false otherwise.
 /// </summary>
 internal override bool ImplementsDynamicParameters
 {
 get { return ScriptBlock.HasDynamicParameters; }
 }

 /// <summary>
 /// The command metadata for the function or filter.
 /// </summary>
 internal override CommandMetadata CommandMetadata
 {
 get
 {
 return _commandMetadata ??
 (_commandMetadata =
 new CommandMetadata(this.ScriptBlock, this.Name, LocalPipeline.GetExecutionContextFromTLS()));
 }
 }

 private CommandMetadata _commandMetadata;

 /// <summary>
 /// The output type(s) is specified in the script block.
 /// </summary>
 public override ReadOnlyCollection<PSTypeName> OutputType
 {
 get { return ScriptBlock.OutputType; }
 }
 }
}