feat: add pull & clone support w/ ssh keys

keepup-cli/src/main/kotlin/com/mineinabyss/keepup/cli/Main.kt

@@ -16,5 +16,6 @@ class KeepupCommand : CliktCommand() {
 fun main(args: Array<String>) = KeepupCommand().subcommands(
     PluginsCommand(),
     ConfigCommand(),
-    TemplateCommand()
+    TemplateCommand(),
+    PullCommand()
 ).main(args)

keepup-cli/src/main/kotlin/com/mineinabyss/keepup/cli/PullCommand.kt

@@ -0,0 +1,79 @@
+package com.mineinabyss.keepup.cli
+import com.github.ajalt.clikt.core.CliktCommand
+import com.github.ajalt.clikt.core.Context
+import com.github.ajalt.clikt.parameters.arguments.argument
+import com.github.ajalt.clikt.parameters.arguments.optional
+import com.github.ajalt.clikt.parameters.options.flag
+import com.github.ajalt.clikt.parameters.options.option
+import com.github.ajalt.clikt.parameters.options.required
+import com.github.ajalt.clikt.parameters.types.path
+import com.mineinabyss.keepup.t
+import kotlin.io.path.*
+
+class PullCommand : CliktCommand(name = "pull"){
+    override fun help(context: Context): String = "Pulls a github repository or clones it if it has not been previously pulled."
+
+    val repo by argument(help = "Github repository to pull, specified as 'owner/repo_name'")
+
+    val branch by argument(help = "Branch to pull").optional()
+
+    val destRoot by option("-d", "--dest", help = "Will place repo as a directory inside this directory.")
+        .path(mustExist = false, canBeFile = false, mustBeWritable = false)
+        .required()
+
+    val keyPath by option("-k", "--key-path", help = "Path to SSH key used to access private repos or get a higher rate limit")
+        .path(mustExist = true, canBeDir = false, mustBeReadable = true)
+
+    val dontStashChanges by option("-n", "--no-stash", help = "Don't stash changes before pulling. If enabled, may fail pull if unable to merge.")
+        .flag(default = false)
+
+    fun runProcess(vararg command: String) {
+        ProcessBuilder()
+            .command(*command)
+            .redirectError(ProcessBuilder.Redirect.INHERIT)
+            .redirectOutput(ProcessBuilder.Redirect.INHERIT)
+            .start()
+            .waitFor()
+    }
+
+    override fun run() {
+        val repoDir = destRoot.resolve(repo.split("/")[1])
+        t.println("Pulling files from repo: $repo, branch: ${branch?: "default"}, to directory: $repoDir.")
+
+        var sshString: String
+        if (keyPath != null) {
+            sshString = "core.sshCommand=ssh -i ${keyPath!!.toAbsolutePath()}"
+        } else {
+            sshString = ""
+        }
+
+        var checkoutCommand: Array<String>
+        if (branch != null) {
+            checkoutCommand = arrayOf("git", "-C", repoDir.toAbsolutePath().toString(), "checkout", branch!!)
+        } else {
+            checkoutCommand = emptyArray()
+        }
+
+        if (!repoDir.exists()) {
+            // Must clone if directory doesn't exist
+            t.println("Repository doesn't exist, cloning into $repoDir instead.")
+            repoDir.createDirectories()
+            runProcess("git", "clone", "-c", sshString, "[email protected]:${repo}.git", repoDir.toAbsolutePath().toString())
+            if (branch != null) { // Checkout desired branch
+                runProcess(*checkoutCommand)
+                runProcess("git", "-C", repoDir.toAbsolutePath().toString(), "pull") // Pull branch, checkout only makes local copy
+            }
+        } else {
+            if (!dontStashChanges) {
+                runProcess(
+                    "git",
+                    "-C",
+                    repoDir.toAbsolutePath().toString(),
+                    "stash"
+                ) // Stash first to discard local changes
+            }
+            runProcess(*checkoutCommand)
+            runProcess("git", "-C", repoDir.toAbsolutePath().toString(), "pull")
+        }
+    }
+}