TerminalSize.swift

/*
 This source file is part of the Swift System open source project

 Copyright (c) 2024 Apple Inc. and the Swift System project authors
 Licensed under Apache License v2.0 with Runtime Library Exception

 See https://swift.org/LICENSE.txt for license information
*/

#if !os(Windows)

import ArgumentParser
import SystemPackage

struct TerminalSize: ParsableCommand {
  static let configuration = CommandConfiguration(
    abstract: "Display terminal window dimensions"
  )

  @Flag(name: .shortAndLong, help: "Show verbose output")
  var verbose: Bool = false

  @Flag(name: .long, help: "Draw a border using the terminal dimensions")
  var border: Bool = false

  @Option(name: .long, help: "Try to set terminal rows (height)")
  var setRows: UInt16?

  @Option(name: .long, help: "Try to set terminal columns (width)")
  var setColumns: UInt16?

  func run() throws {
    guard let terminal = TerminalDescriptor(.standardOutput) else {
      complain("Error: stdout is not a terminal")
      throw ExitCode.failure
    }

    // Try to set size if requested
    if let rows = setRows, let cols = setColumns {
      print("Attempting to set terminal size to \(cols)x\(rows)...")
      let newSize = TerminalDescriptor.WindowSize(rows: rows, columns: cols)
      do {
        try terminal.setWindowSize(newSize)
        print("✓ Successfully set terminal size")
      } catch {
        print("✗ Failed to set terminal size: \(error)")
        print("Note: Setting terminal size may not be supported by your terminal emulator")
      }
      print()
    } else if setRows != nil || setColumns != nil {
      complain("Error: Both --set-rows and --set-columns must be specified together")
      throw ExitCode.failure
    }

    let size = try terminal.windowSize()

    if verbose {
      print("Terminal Window Size:")
      print("  Rows (height):    \(size.rows)")
      print("  Columns (width):  \(size.columns)")

      // Access underlying C struct for pixel dimensions
      let xpixel = size.rawValue.ws_xpixel
      let ypixel = size.rawValue.ws_ypixel
      if xpixel > 0 || ypixel > 0 {
        print("  X pixels:         \(xpixel)")
        print("  Y pixels:         \(ypixel)")
      } else {
        print("  Pixel dimensions: not available")
      }
      print()
      print("This is useful for:")
      print("  - Formatting output to fit the terminal")
      print("  - Creating full-screen terminal UIs")
      print("  - Responsive command-line applications")
    } else {
      print("\(size.columns)x\(size.rows)")
    }

    if border {
      print()
      drawBorder(width: Int(size.columns), height: Int(size.rows))
    }
  }

  private func drawBorder(width: Int, height: Int) {
    // Top border
    print("┌" + String(repeating: "─", count: width - 2) + "┐")

    // Middle rows
    for row in 2..<height {
      if row == height / 2 {
        // Center text
        let text = "\(width)x\(height)"
        let leftPad = (width - 2 - text.count) / 2
        let rightPad = width - 2 - text.count - leftPad
        print("│" + String(repeating: " ", count: leftPad) + text + String(repeating: " ", count: rightPad) + "│")
      } else {
        print("│" + String(repeating: " ", count: width - 2) + "│")
      }
    }

    // Bottom border
    print("└" + String(repeating: "─", count: width - 2) + "┘")
  }
}

#endif