Get latest merged PRs with GitHub APIs

[CmdletBinding()]
param (
    [string]$RepoOwner = "<RepoOwner e.g. pnp>",
    [string]$RepoName = "<RepoName e.g. copilot-pro-dev-samples>",
    [int]$NoOfWeeksSince = 2 # ISO 8601 format, e.g. "2025-07-01T00:00:00Z"
)
begin {
    
    # ------------------------------------------------------------------------------
    # Introduction
    # ------------------------------------------------------------------------------

    Write-Host " Welcome to GitHub PRs, this script will read latest PRs on a Repository" -ForegroundColor Green
    
    # ------------------------------------------------------------------------------

    # Read the Token file get the github token
    $githubTokenFile = "github-token.txt"
    $page = 1
    $perPage = 100

    # Calculate the date since which to fetch PRs
    $sinceDate = (Get-Date).AddDays( - ($NoOfWeeksSince * 7)).ToString("yyyy-MM-ddTHH:mm:ssZ")
    # Prepare CSV file name
    $friendlyDate = $sinceDate -replace ":","-"
    $csvFileName = "MergedPRs_$($RepoOwner)_$($RepoName)_Since$($friendlyDate).csv"
}
process {

    if (Test-Path $githubTokenFile) {
        $githubToken = Get-Content -Path $githubTokenFile -ErrorAction Stop
    }
    else {
        Write-Error "GitHub token file not found: $githubTokenFile"
        exit 1
    }

    $headers = @{
        Authorization = "token $githubToken"
        Accept        = "application/vnd.github+json"
    }

    $allPRs = @()

    do {
        $url = "https://api.github.com/repos/$RepoOwner/$RepoName/pulls?state=closed&sort=created&direction=desc&per_page=$perPage&page=$page"
        $prs = Invoke-RestMethod -Uri $url -Headers $headers

        foreach ($pr in $prs) {
            if ($pr.merged_at -ge $sinceDate -and $pr.state -eq "closed") {
                $allPRs += $pr
            }
        }
        $page++
    } while ($prs.Count -eq $perPage)


    #--------------------------------------------------------------------------------------
    # Produce Report of the latest merged PRs as Output PRs with user login and profile link
    #--------------------------------------------------------------------------------------
    if($allPRs.Count -eq 0) {
        Write-Host "No PRs found that were merged in the last $NoOfWeeksSince weeks." -ForegroundColor Yellow
        return
    }else{
        $formattedList = $allPRs | Select-Object `
        @{Name = "ID"; Expression = { $_.number } },
        @{Name = "PR Title"; Expression = { $_.title } },
        @{Name = "User Login"; Expression = { $_.user.login } }, 
        @{Name = "User Public Profile"; Expression = { $_.user.html_url } },
        @{Name = "Merged"; Expression = { $_.merged_at } } 

        $formattedList | Format-Table -AutoSize

        Write-Host "`nTotal PRs merged in the last $NoOfWeeksSince weeks: $($allPRs.Count)" -ForegroundColor Cyan

        # Write to CSV file
        $formattedList | Export-Csv -Path $csvFileName -NoTypeInformation -Encoding UTF8
        Write-Host "Report saved to $csvFileName"
    }
}
end {
    Write-Host "Done! :)" -ForegroundColor Green
}