update-readme.ps1

param ([string] $class)

$sourceFile = ".\docs\_data\$($class.ToLower()).json"
$destinationFile = ".\README.md"

########### Create a markdown table ##########
Write-Host "Creating new version of $destinationFile based on $sourceFile ..."
$elapsed = Measure-Command -Expression {
    $members = Get-Content -Path $sourceFile | ConvertFrom-Json | Sort-Object Scope, Name
    Write-Host  "`t$($members.Count) $($class.ToLower())s read"
    $items = @()
    $columns = @{}

    ForEach($member in $members) {
        $member.Aliases = $member.Aliases -Join ", "
        $items += $member

        $member.PSObject.Properties | %{
            if(-not $columns.ContainsKey($_.Name) -or $columns[$_.Name] -lt $_.Value.ToString().Length) {
                $columns[$_.Name] = $_.Value.ToString().Length
            }
        }
    }

    ForEach($key in $($columns.Keys)) {
        $columns[$key] = [Math]::Max($columns[$key], $key.Length)
    }

    $keys = "Scope", "Name", "Aliases"

    $table=""
    $header = @()
    ForEach($key in $keys) {
        $header += ('{0,-' + $columns[$key] + '}') -f ($key -creplace '([A-Z])', ' $1').Trim()
    }
    $table += '|' + ($header -join ' | ') + "|`r`n"

    $separator = @()
    ForEach($key in $keys) {
        $separator += '-' * $columns[$key]
    }
    $table += '|' + ($separator -join ' | ') + "|`r`n"

    ForEach($item in $items) {
        $values = @()
        ForEach($key in $keys) {
            $values += ('{0,-' + $columns[$key] + '}') -f $item.($key)
        }
        $table += '|' + ($values -join ' | ') + "|`r`n"
    }
    Write-Host  "`tCreated markdown table with $($table.Split("`r`n").GetUpperBound(0)) lines and a width of $($table.Split("`r`n")[0].Length) chars"

    ########### Extract content of the quick-start ##########

    switch -Exact -CaseSensitive ($class)
    {
        "function" {$classGroup = "expression"}
        "predicate" {$classGroup = "predication"}
    }

    $quickStartFile = ".\docs\_docs\quick-start-$($classGroup.ToLower()).md"
    Write-Host  "`tReading content of $quickStartFile ..."
    [int] $headerMarkup = 0
    ForEach ($line in Get-Content -Path $quickStartFile) {
        if ($headerMarkup -ge 2) {
            if(!$line.Trim().StartsWith("<!-- ")) {
                $quickStart += $line + "`r`n"
            }
        }        
        
        if($line.Trim() -eq "---") {
            $headerMarkup += 1
        }
    }
    ########### Update the sub-part of the readme ##########

    Write-Host  "`tReplacing content in $destinationFile ..."
    $text = ""
    [bool] $skip = $false
    ForEach ($line in Get-Content -Path $destinationFile) {
        if($line.StartsWith("<!-- END ")) {
            $skip = $false
        }

        if (-not $skip) {
            $text += $line + "`r`n"
        }

        if ($line -eq "<!-- START $($class.ToUpper()) TABLE -->"){
            $skip = $true
            $text += $table
            Write-Host  "`tReplaced content of $($class.ToUpper()) table"
        }
        if ($line -eq "<!-- START $($classGroup.ToUpper()) QUICK START -->"){
            $skip = $true
            $text += $quickStart
            Write-Host  "`tReplaced content of $($classGroup.ToUpper()) quick start"
        }
    }
    $text | Out-File -FilePath $destinationFile -NoNewline -Encoding ascii
}
Write-Host "New version of $destinationFile created in $($elapsed.TotalSeconds) seconds"