# Copyright 2012 Aaron Jensen
# 
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# 
#     http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

function Remove-IniEntry
{
    <#
    .SYNOPSIS
    Removes an entry/line/setting from an INI file.
    
    .DESCRIPTION
    A configuration file consists of sections, led by a `[section]` header and followed by `name = value` entries.  This function removes an entry in an INI file.  Something like this:

        [ui]
        username = Regina Spektor <regina@reginaspektor.com>

        [extensions]
        share = 
        extdiff =

    Names are not allowed to contains the equal sign, `=`.  Values can contain any character.  The INI file is parsed using `Split-Ini`.  [See its documentation for more examples.](Split-Ini.html)
    
    If the entry doesn't exist, does nothing.

    .LINK
    Set-IniEntry

    .LINK
    Split-Ini

    .EXAMPLE
    Remove-IniEntry -Path C:\Projects\Carbon\StupidStupid.ini -Section rat -Name tails

    Removes the `tails` item in the `[rat]` section of the `C:\Projects\Carbon\StupidStupid.ini` file.
    #>
    [CmdletBinding(SupportsShouldProcess=$true)]
    param
    (
        [Parameter(Mandatory=$true)]
        [string]
        # The path to the INI file.
        $Path,
        
        [Parameter(Mandatory=$true)]
        [string]
        # The name of the INI entry to remove.
        $Name,
        
        [string]
        # The section of the INI where the entry should be set.
        $Section
    )

    $settings = @{ }
    
    if( Test-Path $Path -PathType Leaf )
    {
        $settings = Split-Ini -Path $Path -AsHashtable
    }
    else
    {
        Write-Error ('INI file {0} not found.' -f $Path)
        return
    }

    $key = $Name
    if( $Section )
    {
        $key = '{0}.{1}' -f $Section,$Name
    }

    if( $settings.ContainsKey( $key ) )
    {
        $lines = New-Object 'Collections.ArrayList'
        Get-Content -Path $Path | ForEach-Object { [void] $lines.Add( $_ ) }
        $null = $lines.RemoveAt( ($settings[$key].LineNumber - 1) )
        if( $PSCmdlet.ShouldProcess( $Path, ('remove INI entry {0}' -f $key) ) )
        {
            Write-Host ("Removing INI entry '{0}' in '{1}'." -f $key,$Path)
            $lines | Out-File -FilePath $Path -Encoding OEM
        }
    }

}