<#
PowerShell script to rename C# Project step-by-step:
* Copying project folder to folder with new project name
* Renaming .csproj file and other files with project name
* Changing project name reference in .sln solution file
* Changing RootNamespace and AssemblyName in .csproj file
* Renaming project inside AssemblyInfo.cs
#>
param(
    [parameter(
        HelpMessage="Existing C# Project path to rename.",
        Mandatory=$true, ValueFromPipeline=$true)]
    [ValidateScript({
        if (Test-Path $_.Trim().Trim('"')) { $true }
        else { throw "Path does not exist: $_" }
    })]
    [string]$ProjectFilePath,

    [parameter(
        HelpMessage="New project file name, without extension.",
        Mandatory=$true)]
    [string]$NewProjectName,

    [parameter(
        HelpMessage="Path to solution file.",
        Mandatory=$true)]
    [ValidateScript({
        if (Test-Path $_.Trim().Trim('"')) { $true }
        else { throw "Path does not exist: $_" }
    })]
    [string]$SolutionFilePath,

    [parameter(
        HelpMessage="Relative path to AssemblyInfo.cs file, e.g. "".\Properties\AssemblyInfo.cs"".`nSpecify empty string to skip AssemblyInfo processing.",
        Mandatory=$true)]
    [AllowEmptyString()]
    [string]$RelativeAssemblyInfoPath
)

$ProjectFilePath = $ProjectFilePath.Trim().Trim('"')
$SolutionFilePath = $SolutionFilePath.Trim().Trim('"')

function ProceedOrExit {
    if ($?) { echo "Proceed.." } else { echo "Script FAILED! Exiting.."; exit 1 }
}

echo "Rename project from '$OldProjectName' to '$NewProjectName'"
echo "=========="

$OldProjectFolder  = Split-Path $ProjectFilePath
echo "1. Set current location to project folder '$OldProjectFolder'"
cd $OldProjectFolder
ProceedOrExit

$NewProjectFolder="..\$NewProjectName"
echo "----------"
echo "2. Copy project folder to '$NewProjectFolder'"
copy . $NewProjectFolder -Recurse #-WhatIf
ProceedOrExit

$NewProjectFolder=Resolve-Path $NewProjectFolder
echo "----------"
echo "3. Set current location to New project folder '$NewProjectFolder'"
cd $NewProjectFolder
ProceedOrExit

echo "----------"
echo "4. Rename .proj and other files inside '$NewProjectFolder'"

$OldProjectName=[IO.Path]::GetFileNameWithoutExtension($ProjectFilePath)
dir -Include "$OldProjectName.*" -Recurse |
    ren -NewName {$_.Name -replace [regex]("^"+$OldProjectName+"\b"), $NewProjectName} #-WhatIf
ProceedOrExit

echo "----------"
echo "5. Copy solution file to '$SolutionFilePath.backup'"
copy "$SolutionFilePath" "$SolutionFilePath.backup" #-WhatIf
ProceedOrExit

echo "----------"
echo "6. Rename project reference inside solution file."

# Put get-content in () brackets to read whole file before modifying it.
(Get-Content $SolutionFilePath) |
   % { if ($_ -match ("\b(" + $OldProjectName + ")\b\.csproj")) { $_ -replace $($matches[1]), $NewProjectName } else { $_ }} |
   Set-Content $SolutionFilePath
ProceedOrExit

$NewProjectFile="$NewProjectName.csproj"
echo "----------"
echo "7. Rename project in tags AssemblyName and RootNamespace inside '$NewProjectFile'"

(Get-Content $NewProjectFile) |
    % { if ($_ -match ("<(?:AssemblyName|RootNamespace)>(" + $OldProjectName +")</")) { $_ -replace $($matches[1]), $NewProjectName } else { $_ }} |
    Set-Content $NewProjectFile
ProceedOrExit

$RelativeAssemblyInfoPath = $RelativeAssemblyInfoPath.Trim().Trim('"')
if ($RelativeAssemblyInfoPath) {
    echo "----------"
    echo "8. Rename project inside '$RelativeAssemblyInfoPath'"

    if (!(Test-Path $RelativeAssemblyInfoPath)) { echo "ERROR: Path does not exist." }
    else {
        (Get-Content $RelativeAssemblyInfoPath) |
           % { if ($_ -match ("""\b("+$OldProjectName+")\b""")) { $_ -replace $($matches[1]), $NewProjectName } else { $_ }} |
           Set-Content $RelativeAssemblyInfoPath #-WhatIf
        ProceedOrExit
    }
}

echo "=========="
echo "DONE."