<#@ assembly name="System.Core" #>
<#@ assembly name="System.Data" #>
<#@ assembly name="EnvDTE" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Text" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ import namespace="System.Data"#>
<#@ import namespace="System.IO"#>
<#@ import namespace="Microsoft.VisualStudio.TextTemplating"#>

<#+
// T4 Template Block manager for handling multiple file outputs more easily.
// Copyright (c) Microsoft Corporation.All rights reserved.
// This source code is made available under the terms of the Microsoft Public License (MS-PL)

// Manager class records the various blocks so it can split them up
class Manager
{
    public struct Block
    {
        public string Name;
        public int Start, Length;
    }

    public List<Block> blocks = new List<Block>();
    public Block currentBlock;
    public Block footerBlock = new Block();
    public Block headerBlock = new Block();
    public ITextTemplatingEngineHost host;
    public ManagementStrategy strategy;
    public StringBuilder template;
    public string OutputPath { get; set; }

    public Manager(ITextTemplatingEngineHost host, StringBuilder template, bool commonHeader)
    {
        this.host = host;
        this.template = template;
        OutputPath = string.Empty;
        strategy = ManagementStrategy.Create(host);
    }

    public void StartBlock(string name)
    {
        currentBlock = new Block { Name = name, Start = template.Length };
    }

    public void StartFooter()
    {
        footerBlock.Start = template.Length;
    }

    public void EndFooter()
    {
        footerBlock.Length = template.Length - footerBlock.Start;
    }

    public void StartHeader()
    {
        headerBlock.Start = template.Length;
    }

    public void EndHeader()
    {
        headerBlock.Length = template.Length - headerBlock.Start;
    }    

    public void EndBlock()
    {
        currentBlock.Length = template.Length - currentBlock.Start;
        blocks.Add(currentBlock);
    }

    public void Process(bool split)
    {
        string header = template.ToString(headerBlock.Start, headerBlock.Length);
        string footer = template.ToString(footerBlock.Start, footerBlock.Length);
        blocks.Reverse();
        foreach(Block block in blocks) {
            string fileName = Path.Combine(OutputPath, block.Name);
            if (split) {
                string content = header + template.ToString(block.Start, block.Length) + footer;
                strategy.CreateFile(fileName, content);
                template.Remove(block.Start, block.Length);
            } else {
                strategy.DeleteFile(fileName);
            }
        }
    }
}

class ManagementStrategy
{
    internal static ManagementStrategy Create(ITextTemplatingEngineHost host)
    {
        return (host is IServiceProvider) ? new VSManagementStrategy(host) : new ManagementStrategy(host);
    }

    internal ManagementStrategy(ITextTemplatingEngineHost host) { }

    internal virtual void CreateFile(string fileName, string content)
    {
        File.WriteAllText(fileName, content);
    }

    internal virtual void DeleteFile(string fileName)
    {
        if (File.Exists(fileName))
            File.Delete(fileName);
    }
}

class VSManagementStrategy : ManagementStrategy
{
    private EnvDTE.ProjectItem templateProjectItem;

    internal VSManagementStrategy(ITextTemplatingEngineHost host) : base(host)
    {
        IServiceProvider hostServiceProvider = (IServiceProvider)host;
        if (hostServiceProvider == null)
            throw new ArgumentNullException("Could not obtain hostServiceProvider");

        EnvDTE.DTE dte = (EnvDTE.DTE)hostServiceProvider.GetService(typeof(EnvDTE.DTE));
        if (dte == null)
            throw new ArgumentNullException("Could not obtain DTE from host");

        templateProjectItem = dte.Solution.FindProjectItem(host.TemplateFile);
    }

    internal override void CreateFile(string fileName, string content)
    {
        base.CreateFile(fileName, content);
        ((EventHandler)delegate { templateProjectItem.ProjectItems.AddFromFile(fileName); }).BeginInvoke(null, null, null, null);
    }

    internal override void DeleteFile(string fileName)
    {
        ((EventHandler)delegate { FindAndDeleteFile(fileName); }).BeginInvoke(null, null, null, null);
    }

    private void FindAndDeleteFile(string fileName)
    {
        foreach(EnvDTE.ProjectItem projectItem in templateProjectItem.ProjectItems)
        {
            if (projectItem.get_FileNames(0) == fileName)
            {
                projectItem.Delete();
                return;
            }
        }
    }
}
#>