# Download one report as JSON and CSV.
# Works in Windows PowerShell 5.1 and PowerShell 7.
$ErrorActionPreference = 'Stop'

# Your portal address and the report to download.
$BaseUrl = 'https://reports.example.com/yourcompany'
$Report  = 'AdminChargeDetail'

# The folder the JSON and CSV files are saved in. The default is a Reports
# folder in your Documents folder. To use another folder, replace the line
# with its full path in single quotes, for example:
#   $OutDir = 'D:\Finance\Reports'
$OutDir = Join-Path ([Environment]::GetFolderPath('MyDocuments')) 'Reports'

# Where step 1 saved your credentials. Leave this as it is.
$CredDir = Join-Path $env:USERPROFILE '.report-api'

# Older Windows PowerShell setups may not offer TLS 1.2 unless asked.
[Net.ServicePointManager]::SecurityProtocol =
    [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12

# Windows PowerShell 5.1 slows large downloads badly while it draws a
# progress bar. The script prints its own messages instead.
$ProgressPreference = 'SilentlyContinue'

$Invariant = [Globalization.CultureInfo]::InvariantCulture
$Utf8NoBom = New-Object System.Text.UTF8Encoding $false
$Utf8Bom   = New-Object System.Text.UTF8Encoding $true

# One CSV cell: nested values as JSON text, dates as ISO text,
# numbers with a "." decimal point whatever the machine's language.
function Format-Cell($Value) {
    if ($null -eq $Value) { return '' }
    if ($Value -is [string]) { return $Value }
    if ($Value -is [bool]) { return $Value.ToString().ToLowerInvariant() }
    if ($Value -is [datetime]) {
        return $Value.ToString('yyyy-MM-ddTHH:mm:ss.FFFFFFF', $Invariant)
    }
    if ($Value -is [System.Management.Automation.PSCustomObject] -or
        $Value -is [System.Collections.IEnumerable]) {
        return (ConvertTo-Json -InputObject $Value -Compress -Depth 20)
    }
    if ($Value -is [IFormattable]) { return $Value.ToString($null, $Invariant) }
    return "$Value"
}

$credential = Import-Clixml (Join-Path $CredDir 'credential.xml')
New-Item -ItemType Directory -Force -Path $OutDir | Out-Null
$raw = Join-Path $OutDir "$Report.raw.json"
$session = $null

try {
    $body = @{
        user_name = $credential.UserName
        password  = $credential.GetNetworkCredential().Password
    } | ConvertTo-Json -Compress
    Write-Host "Signing in to $BaseUrl"
    try {
        Invoke-RestMethod -Method Post -Uri "$BaseUrl/api/login" -UseBasicParsing `
            -ContentType 'application/json' -Body $body `
            -SessionVariable session | Out-Null
    } catch {
        throw "Sign-in failed: $($_.Exception.Message)"
    } finally {
        Remove-Variable body -ErrorAction SilentlyContinue
    }

    # Save the response as received, then read it as UTF-8. The server does
    # not name a character set, and Windows PowerShell 5.1 would otherwise
    # misread accented characters.
    Write-Host "Downloading the $Report report. A large report can take several"
    Write-Host "minutes, and nothing more is shown until it finishes."
    Invoke-RestMethod -Uri "$BaseUrl/api/report/$Report" -UseBasicParsing `
        -WebSession $session -OutFile $raw
    $rows = @((Get-Content -Path $raw -Raw -Encoding UTF8 | ConvertFrom-Json).d)

    $json = Join-Path $OutDir "$Report.json"
    $jsonText = ConvertTo-Json -InputObject $rows -Depth 20
    [IO.File]::WriteAllText($json, $jsonText, $Utf8NoBom)

    # The CSV starts with a UTF-8 byte-order mark so Excel reads accented
    # characters correctly.
    $csv = Join-Path $OutDir "$Report.csv"
    $csvText = ''
    if ($rows.Count -gt 0) {
        $columns = @($rows[0].PSObject.Properties.Name)
        $lines = $rows | ForEach-Object {
            $row = $_
            $cells = [ordered]@{}
            foreach ($column in $columns) { $cells[$column] = Format-Cell $row.$column }
            [pscustomobject]$cells
        } | ConvertTo-Csv -NoTypeInformation
        $csvText = ($lines -join "`r`n") + "`r`n"
    }
    [IO.File]::WriteAllText($csv, $csvText, $Utf8Bom)

    Write-Output "Saved $json and $csv"
} finally {
    if ($session) {
        try {
            Invoke-RestMethod -Uri "$BaseUrl/api/logout" -UseBasicParsing `
                -WebSession $session | Out-Null
        } catch { }
    }
    Remove-Item -Path $raw -ErrorAction SilentlyContinue
}