#!/usr/bin/env pwsh -c

<#
.DESCRIPTION
Creates a GitHub pull request for a given branch if it doesn't already exist
.PARAMETER RepoOwner
The GitHub repository owner to create the pull request against.
.PARAMETER RepoName
The GitHub repository name to create the pull request against.
.PARAMETER BaseBranch
The base or target branch we want the pull request to be against.
.PARAMETER PROwner
The owner of the branch we want to create a pull request for.
.PARAMETER PRBranch
The branch which we want to create a pull request for.
.PARAMETER AuthToken
A personal access token
.PARAMETER PRTitle
The title of the pull request.
.PARAMETER PRBody
The body message for the pull request. 
.PARAMETER PRLabels
The labels added to the PRs. Multple labels seperated by comma, e.g "bug, service"
.PARAMETER UserReviewers
User reviewers to request after opening the PR. Users should be a comma-
separated list with no preceeding `@` symbol (e.g. "user1,usertwo,user3")
.PARAMETER TeamReviewers
List of github teams to add as reviewers
.PARAMETER Assignees
Users to assign to the PR after opening. Users should be a comma-separated list
with no preceeding `@` symbol (e.g. "user1,usertwo,user3")
.PARAMETER CloseAfterOpenForTesting
Close the PR after opening to save on CI resources and prevent alerts to code
owners, assignees, requested reviewers, or others.
.PARAMETER OpenAsDraft
Opens the PR as a draft
#>
[CmdletBinding(SupportsShouldProcess = $true)]
param(
  [Parameter(Mandatory = $true)]
  [string]$RepoOwner,

  [Parameter(Mandatory = $true)]
  [string]$RepoName,

  [Parameter(Mandatory = $true)]
  [string]$BaseBranch,

  [Parameter(Mandatory = $true)]
  [string]$PROwner,

  [Parameter(Mandatory = $true)]
  [string]$PRBranch,

  [Parameter(Mandatory = $true)]
  [string]$AuthToken,

  [Parameter(Mandatory = $true)]
  [string]$PRTitle,

  [Parameter(Mandatory = $false)]
  [string]$PRBody = $PRTitle,

  [string]$PRLabels,

  [string]$UserReviewers,

  [string]$TeamReviewers,

  [string]$Assignees,

  [boolean]$CloseAfterOpenForTesting=$false,

  [boolean]$OpenAsDraft=$false
)

. (Join-Path $PSScriptRoot common.ps1)

try {
  $resp = Get-GitHubPullRequests -RepoOwner $RepoOwner -RepoName $RepoName `
  -Head "${PROwner}:${PRBranch}" -Base $BaseBranch -AuthToken $AuthToken
}
catch { 
  LogError "Get-GitHubPullRequests failed with exception:`n$_"
  exit 1
}

$resp | Write-Verbose

if ($resp.Count -gt 0) {
  LogDebug "Pull request already exists $($resp[0].html_url)"
  # setting variable to reference the pull request by number
  Write-Host "##vso[task.setvariable variable=Submitted.PullRequest.Number]$($resp[0].number)"
}
else {
  try {
    $resp = New-GitHubPullRequest `
      -RepoOwner $RepoOwner `
      -RepoName $RepoName `
      -Title $PRTitle `
      -Head "${PROwner}:${PRBranch}" `
      -Base $BaseBranch `
      -Body $PRBody `
      -Maintainer_Can_Modify $true `
      -Draft:$OpenAsDraft `
      -AuthToken $AuthToken

    $resp | Write-Verbose
    LogDebug "Pull request created https://github.com/$RepoOwner/$RepoName/pull/$($resp.number)"
  
    $prOwnerUser = $resp.user.login

    # setting variable to reference the pull request by number
    Write-Host "##vso[task.setvariable variable=Submitted.PullRequest.Number]$($resp.number)"

    # ensure that the user that was used to create the PR is not attempted to add as a reviewer
    # we cast to an array to ensure that length-1 arrays actually stay as array values
    $cleanedUsers = @(SplitParameterArray -members $UserReviewers) | ? { $_ -ne $prOwnerUser -and $null -ne $_ }
    $cleanedTeamReviewers = @(SplitParameterArray -members $TeamReviewers) | ? { $_ -ne $prOwnerUser -and $null -ne $_ }

    if ($cleanedUsers -or $cleanedTeamReviewers) {
      Add-GitHubPullRequestReviewers -RepoOwner $RepoOwner -RepoName $RepoName -PrNumber $resp.number `
      -Users $cleanedUsers -Teams $cleanedTeamReviewers -AuthToken $AuthToken
    }

    if ($CloseAfterOpenForTesting) {
      $prState = "closed"
      LogDebug "Updating https://github.com/$RepoOwner/$RepoName/pull/$($resp.number) state to closed because this was only testing."
    }
    else {
      $prState = "open"
    }

    Update-GitHubIssue -RepoOwner $RepoOwner -RepoName $RepoName -IssueNumber $resp.number `
    -State $prState -Labels $PRLabels -Assignees $Assignees -AuthToken $AuthToken
  }
  catch {
    LogError "Call to GitHub API failed with exception:`n$_"
    exit 1
  }
}