bumpBuildVersion

#!/usr/bin/swift 

import Foundation

struct Constants {
	static let gitPath = "/usr/bin/git"
	static let agvtoolPath = "/usr/bin/agvtool"
}

extension String {
	func stringByTrimmingWhitespace() -> String {
		return self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
	}
	
	func stringByTrimmingWhitespaceAndNewline() -> String {
		return self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
	}
}

struct SystemTaskExecutor
{
	func executeSystemCommandWithLaunchPath(launchPath: String, arguments: String) -> String? {
		let task = NSTask()
		task.launchPath = launchPath
		task.arguments = arguments.characters.split{$0 == " "}.map(String.init);

		let pipe = NSPipe()
		task.standardOutput = pipe
		task.launch()

		let data = pipe.fileHandleForReading.readDataToEndOfFile()
		let output = String(data:data, encoding:NSUTF8StringEncoding) as String?
		return output
	}
}

struct GitUtility {	
	func tagBranchWithTagName(tagName: String) -> String? {
		return executeGitCommandWithArguments("tag " + tagName.stringByTrimmingWhitespaceAndNewline())
	}
	
	func createBranchNamed(branchName: String) {
		executeGitCommandWithArguments("branch " + branchName)
	}
	
	func deleteBranchNamed(branchName: String) {
		executeGitCommandWithArguments("branch -D " + branchName)
	}
	
	func switchToBranchNamed(branchName: String) {
		executeGitCommandWithArguments("checkout " + branchName)
	}
	
	func currentGitBranch() -> String? {
		return executeGitCommandWithArguments("rev-parse --abbrev-ref HEAD")?.stringByTrimmingWhitespaceAndNewline()
	}

	// MARK: private

	private func executeGitCommandWithArguments(arguments: String) -> String? {
		let taskExecutor = SystemTaskExecutor()
		return taskExecutor.executeSystemCommandWithLaunchPath(Constants.gitPath, arguments:arguments)
	}
}

struct VersionStringTransformer {
	func nextBranchName(branchName: String) -> String {
		return nextMajorMinorInternalVersion(branchName, separator: "_")
	}
	
	func nextBuildVersionNumber(version: String) -> String {
		return nextMajorMinorInternalVersion(version, separator: ".")
	}
	
	// MARK: private
	
	private func nextMajorMinorInternalVersion(version: String, separator: Character) -> String {
		assert(version.characters.count > 0)
		
		var nextVersionString = version
		var versionComponents = version.stringByTrimmingWhitespaceAndNewline().characters.split{$0 == separator}.map(String.init)
		
		if let lastVersionComponent = versionComponents.last {
			let lastNumber = Int(lastVersionComponent)
			
			if let safeLastNumber = lastNumber {
				let nextVersionNumber = Int(safeLastNumber + 1)
				
				let lastIndex = (versionComponents.count - 1)
				versionComponents[lastIndex] = String(nextVersionNumber)
			}
			nextVersionString = versionComponents.joinWithSeparator(String(separator))
		}
		return nextVersionString
	}
}

func tagNameFromBranchName(branchName: String) -> String {
	let safeBranchName = branchName.stringByTrimmingWhitespaceAndNewline()
	return String(safeBranchName.characters.dropFirst())
}

func executeArgvtoolWithArguments(arguments: String) -> String? {
	return SystemTaskExecutor().executeSystemCommandWithLaunchPath(Constants.agvtoolPath, arguments: arguments)
}

func bumpBuildVersionNumber() {	
	if let currentBuildVersionNumber = executeArgvtoolWithArguments("what-version -terse") {
		let nextBuildVersionNumber = VersionStringTransformer().nextBuildVersionNumber(currentBuildVersionNumber)
		executeArgvtoolWithArguments("new-version -all " + nextBuildVersionNumber)
	}
}

func main() {
	let gitUtility = GitUtility()	
	let branch = gitUtility.currentGitBranch()
	
	if let currentBranch = branch {
		gitUtility.tagBranchWithTagName(tagNameFromBranchName(currentBranch))
		
		let newBranchName = VersionStringTransformer().nextBranchName(currentBranch)
		gitUtility.createBranchNamed(newBranchName)
		gitUtility.switchToBranchNamed(newBranchName)
		
		let oldBranchName = currentBranch
		gitUtility.deleteBranchNamed(oldBranchName)
		
		bumpBuildVersionNumber()
	
		print("\nCurrently the script only places a tag in the repo")
		print("Things on the list to implement:")
		print("\t- abort execution if there are local changes in the repo (you don't want to release if there are some local changes!)")
		print("\t- automatically make a commit updating version number in the info.plist file")
		print("\t- print more verbose information about what's happening behind the scenes")		
	}
}
main();