[CmdletBinding()]
param(
    [Parameter()]
    [string]$SourcePath = (Join-Path $PSScriptRoot '..\app\src'),

    [Parameter()]
    [switch]$ShowFiles
)

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

function Get-CodeLineStatistics {
    param(
        [Parameter(Mandatory)]
        [string]$FilePath
    )

    $statistics = [ordered]@{
        TotalLines = 0
        BlankLines = 0
        CommentOnlyLines = 0
        PreprocessorLines = 0
        CodeLines = 0
    }
    $inBlockComment = $false
    $inRawString = $false
    $rawStringTerminator = ''

    foreach ($line in [System.IO.File]::ReadLines($FilePath, [System.Text.UTF8Encoding]::new($false))) {
        $statistics.TotalLines++
        $index = 0
        $code = [System.Text.StringBuilder]::new()
        $containsComment = $inBlockComment

        while ($index -lt $line.Length) {
            if ($inRawString) {
                $terminatorIndex = $line.IndexOf($rawStringTerminator, $index, [System.StringComparison]::Ordinal)
                if ($terminatorIndex -lt 0) {
                    [void]$code.Append($line.Substring($index))
                    $index = $line.Length
                    continue
                }

                [void]$code.Append($line.Substring($index, $terminatorIndex + $rawStringTerminator.Length - $index))
                $index = $terminatorIndex + $rawStringTerminator.Length
                $inRawString = $false
                continue
            }

            if ($inBlockComment) {
                $containsComment = $true
                $commentEnd = $line.IndexOf('*/', $index, [System.StringComparison]::Ordinal)
                if ($commentEnd -lt 0) {
                    $index = $line.Length
                    continue
                }

                $index = $commentEnd + 2
                $inBlockComment = $false
                continue
            }

            $current = $line[$index]
            $next = if ($index + 1 -lt $line.Length) { $line[$index + 1] } else { [char]0 }

            if ($current -eq '/' -and $next -eq '/') {
                $containsComment = $true
                break
            }

            if ($current -eq '/' -and $next -eq '*') {
                $containsComment = $true
                $inBlockComment = $true
                $index += 2
                continue
            }

            if ($current -eq 'R' -and $next -eq '"') {
                $delimiterStart = $index + 2
                $openParenthesis = $line.IndexOf('(', $delimiterStart)
                if ($openParenthesis -ge 0 -and $openParenthesis - $delimiterStart -le 16) {
                    $delimiter = $line.Substring($delimiterStart, $openParenthesis - $delimiterStart)
                    if ($delimiter -notmatch '[\s\\()]') {
                        $rawStringTerminator = ')' + $delimiter + '"'
                        [void]$code.Append($line.Substring($index, $openParenthesis - $index + 1))
                        $index = $openParenthesis + 1
                        $inRawString = $true
                        continue
                    }
                }
            }

            if ($current -eq '"' -or $current -eq "'") {
                $quote = $current
                [void]$code.Append($quote)
                $index++
                while ($index -lt $line.Length) {
                    $stringCharacter = $line[$index]
                    [void]$code.Append($stringCharacter)
                    $index++
                    if ($stringCharacter -eq '\\' -and $index -lt $line.Length) {
                        [void]$code.Append($line[$index])
                        $index++
                        continue
                    }
                    if ($stringCharacter -eq $quote) {
                        break
                    }
                }
                continue
            }

            [void]$code.Append($current)
            $index++
        }

        $remaining = $code.ToString().Trim()
        if ([string]::IsNullOrWhiteSpace($line)) {
            $statistics.BlankLines++
        }
        elseif ($remaining.StartsWith('#')) {
            $statistics.PreprocessorLines++
        }
        elseif (-not [string]::IsNullOrWhiteSpace($remaining)) {
            $statistics.CodeLines++
        }
        elseif ($containsComment) {
            $statistics.CommentOnlyLines++
        }
        else {
            $statistics.BlankLines++
        }
    }

    return [pscustomobject]$statistics
}

$resolvedSourcePath = (Resolve-Path -LiteralPath $SourcePath).Path
$files = Get-ChildItem -LiteralPath $resolvedSourcePath -Recurse -File -Filter '*.cpp' | Sort-Object FullName
if ($files.Count -eq 0) {
    throw "未在 '$resolvedSourcePath' 找到 .cpp 文件"
}

$fileResults = foreach ($file in $files) {
    $statistics = Get-CodeLineStatistics -FilePath $file.FullName
    [pscustomobject]@{
        File = $file.FullName.Substring($resolvedSourcePath.Length).TrimStart('\', '/')
        CodeLines = $statistics.CodeLines
        TotalLines = $statistics.TotalLines
        BlankLines = $statistics.BlankLines
        CommentOnlyLines = $statistics.CommentOnlyLines
        PreprocessorLines = $statistics.PreprocessorLines
    }
}

$total = [pscustomobject]@{
    File = '合计'
    CodeLines = [int]($fileResults | Measure-Object -Property CodeLines -Sum).Sum
    TotalLines = [int]($fileResults | Measure-Object -Property TotalLines -Sum).Sum
    BlankLines = [int]($fileResults | Measure-Object -Property BlankLines -Sum).Sum
    CommentOnlyLines = [int]($fileResults | Measure-Object -Property CommentOnlyLines -Sum).Sum
    PreprocessorLines = [int]($fileResults | Measure-Object -Property PreprocessorLines -Sum).Sum
}

Write-Host "扫描目录: $resolvedSourcePath"
Write-Host "统计范围: $($files.Count) 个 .cpp 文件，不统计 .h；移除注释及 # 预处理指令后统计代码行"
Write-Host "总行数: $($total.TotalLines)"
Write-Host "纯 C++ 代码: $($total.CodeLines) 行"
Write-Host "空白行: $($total.BlankLines) | 纯注释行: $($total.CommentOnlyLines) | 预处理行: $($total.PreprocessorLines)"

if ($ShowFiles) {
    $fileResults | Format-Table File, CodeLines, TotalLines, BlankLines, CommentOnlyLines, PreprocessorLines -AutoSize
}