app/phpmon/Common/PHP/PHP Version/PhpHelper.swift

//
//  PhpHelper.swift
//  PHP Monitor
//
//  Created by Nico Verbruggen on 17/03/2022.
//  Copyright © 2022 Nico Verbruggen. All rights reserved.
//

import Foundation

class PhpHelper {

    static let keyPhrase = "This file was automatically generated by PHP Monitor."

    public static func generate(for version: String) {
        // Take the PHP version (e.g. "7.2") and generate a dotless version
        let dotless = version.replacingOccurrences(of: ".", with: "")

        // Determine the dotless name for this PHP version
        let destination = "/Users/\(Paths.whoami)/.config/phpmon/bin/pm\(dotless)"

        // Check if the ~/.config/phpmon/bin directory is in the PATH
        let inPath = Shell.user.PATH.contains("/Users/\(Paths.whoami)/.config/phpmon/bin")

        // Check if we can create symlinks (`/usr/local/bin` must be writable)
        let canWriteSymlinks = FileManager.default.isWritableFile(atPath: "/usr/local/bin/")

        do {
            Shell.run("mkdir -p ~/.config/phpmon/bin")

            if FileManager.default.fileExists(atPath: destination) {
                let contents = try String(contentsOfFile: destination)
                if !contents.contains(keyPhrase) {
                    Log.info("The file at '\(destination)' already exists and was not generated by PHP Monitor "
                             + "(or is unreadable). Not updating this file.")
                    return
                }
            }

            // Let's follow the symlink to the PHP binary folder
            let path = URL(fileURLWithPath: "\(Paths.optPath)/php@\(version)/bin")
                .resolvingSymlinksInPath().path

            // The contents of the script!
            let script = """
                #!/bin/zsh
                # \(keyPhrase)
                # It reflects the location of PHP \(version)'s binaries on your system.
                # Usage: . pm\(dotless)
                [[ $ZSH_EVAL_CONTEXT =~ :file$ ]] \\
                    && echo "PHP Monitor has enabled this terminal to use PHP \(version)." \\
                    || echo "You must run '. pm\(dotless)' (or 'source pm\(dotless)') instead!";
                export PATH=\(path):$PATH
                """

            // Write to the destination
            try script.write(
                to: URL(fileURLWithPath: destination),
                atomically: true,
                encoding: String.Encoding.utf8
            )

            // Make sure the file is executable
            Shell.run("chmod +x \(destination)")

            // Create a symlink if the folder is not in the PATH
            if !inPath {
                // First, check if we can create symlinks at all
                if !canWriteSymlinks {
                    Log.err("PHP Monitor does not have permission to symlink `/usr/local/bin/\(dotless)`.")
                    return
                }

                // Write the symlink
                self.createSymlink(dotless)
            }
        } catch {
            print(error)
            Log.err("Could not write PHP Monitor helper for PHP \(version) to \(destination))")
        }
    }

    private static func createSymlink(_ dotless: String) {
        let source = "/Users/\(Paths.whoami)/.config/phpmon/bin/pm\(dotless)"
        let destination = "/usr/local/bin/pm\(dotless)"

        if !Filesystem.fileExists(destination) {
            Log.info("Creating new symlink: \(destination)")
            Shell.run("ln -s \(source) \(destination)")
            return
        }

        if !Filesystem.fileIsSymlink(destination) {
            Log.info("Overwriting existing file with new symlink: \(destination)")
            Shell.run("ln -fs \(source) \(destination)")
            return
        }

        Log.info("Symlink in \(destination) already exists, OK.")
    }
}