#!/usr/bin/python3

import math
import os
import pygit2
import shutil
import sys
import time

def printProgressBar(title, value, total, overwrite = False):
	terminalSize = shutil.get_terminal_size((80, 20))
	progress = value / total if total > 0 else 1
	progressText = "{: >3d} %".format(math.floor(progress * 100))
	remainingWidth = terminalSize.columns - len(title) - len(progressText) - 4
	progressBarWidth = min(remainingWidth, 94)
	blankWidth = remainingWidth - progressBarWidth
	filledWidth = math.floor(progressBarWidth * progress)
	progressBar = "#" * filledWidth + "-" * (progressBarWidth - filledWidth)

	if overwrite:
		print("\x1b[1A\x1b[2K", end = "")

	print("{} {}[{}] {}".format(title, " " * blankWidth, progressBar, progressText))

def printCloneProgress(transferProgress):
	printProgressBar("Cloning the repository", transferProgress.received_objects, transferProgress.total_objects, overwrite = True)

def printFetchProgress(transferProgress):
	printProgressBar("Updating the repository", transferProgress.received_objects, transferProgress.total_objects, overwrite = True)

def printPushProgress(transferProgress):
	printProgressBar("Pushing changes to the repository", transferProgress.received_objects, transferProgress.total_objects, overwrite = True)

def checkPushAccepted(refname, message):
	if message is not None:
		raise Exception("couldn’t push {} to the remote: {}".format(refname, message))

class BenchmarkRepository:
	def __init__(self, config):
		self.basePath = config["basePath"]
		self.remote = config["remote"]
		self.remoteUser = config["remoteUser"]
		self.userName = config["userName"]
		self.userEMail = config["userEMail"]
		self.userSigningKey = config["userSigningKey"] if "userSigningKey" in config else None
		self.branches = config["branches"] if "branches" in config else {"master": "master", "results": "results", "config": "config", "status": "status"}
		self.statusLogSize = config["statusLogSize"]
		self.worktrees = {}

		remoteUser = pygit2.credentials.KeypairFromAgent(self.remoteUser)
		callbacks = pygit2.RemoteCallbacks(credentials = remoteUser)

		# check for an existing repository
		if os.path.isdir(self.branchDir("master")):
			repositoryPath = pygit2.discover_repository(self.branchDir("master"))

			if repositoryPath is None:
				raise Exception("{} exists but is not a Git directory".format(self.branchDir("master")))

			callbacks.transfer_progress = printFetchProgress

			self.repository = pygit2.Repository(repositoryPath)

			for remote in self.repository.remotes:
				printProgressBar("Updating the repository", 0, 1)
				remote.fetch(callbacks = callbacks)
				printProgressBar("Updating the repository", 1, 1, overwrite = True)

			self.forceUpdateBranch("master", self.repository)

			try:
				for branchName in ["results", "config", "status"]:
					print("Updating branch {}".format(branchName))
					worktree = pygit2.Repository(self.repository.lookup_worktree(branchName).path)
					self.worktrees[branchName] = worktree
					self.forceUpdateBranch(branchName, worktree)
			except pygit2.GitError:
				raise Exception("Worktrees are not properly set up")
		else:
			callbacks.transfer_progress = printCloneProgress

			printProgressBar("Cloning the repository", 0, 1)
			self.repository = pygit2.clone_repository(self.remote, self.branchDir("master"), callbacks = callbacks, checkout_branch = self.branches["master"])
			self.repository = pygit2.Repository(self.repository.path)
			printProgressBar("Cloning the repository", 1, 1, overwrite = True)

			for branchName in ["results", "config", "status"]:
				print("Preparing branch {}".format(branchName))
				worktree = pygit2.Repository(self.repository.add_worktree(branchName, self.branchDir(branchName)).path)
				self.worktrees[branchName] = worktree
				remoteReference = worktree.lookup_reference(self.remoteBranchReference(branchName))
				localReference = worktree.create_reference(self.localBranchReference(branchName), remoteReference.resolve().target)
				self.forceUpdateBranch(branchName, worktree)

	def path(self, branchName, path):
		return os.path.join(self.branchDir(branchName), path)

	def branchDir(self, branchName):
		return os.path.join(self.basePath, branchName)

	def localBranchReference(self, branchName):
		return "refs/heads/{}".format(branchName)

	def remoteBranchReference(self, branchName):
		return "refs/remotes/origin/{}".format(self.branches[branchName])

	def forceUpdateBranch(self, branchName, worktree):
		remoteReference = worktree.lookup_reference(self.remoteBranchReference(branchName))
		localReference = worktree.lookup_reference(self.localBranchReference(branchName))
		localReference.set_target(remoteReference.resolve().target)
		worktree.checkout(self.localBranchReference(branchName), strategy = pygit2.GIT_CHECKOUT_FORCE | pygit2.GIT_CHECKOUT_RECREATE_MISSING)

	def commit(self, branchName, message, files):
		worktree = self.worktrees[branchName]
		index = worktree.index

		for file in files:
			index.add(file)

		tree = index.write_tree()
		author = pygit2.Signature(self.userName, self.userEMail)
		worktree.create_commit(self.localBranchReference(branchName), author, author, message, tree, [worktree.head.peel().hex])

	def push(self, branchName):
		printProgressBar("Pushing changes to the repository", 0, 1)
		remoteUser = pygit2.credentials.KeypairFromAgent(self.remoteUser)
		callbacks = pygit2.RemoteCallbacks(credentials = remoteUser)
		callbacks.transfer_progress = printPushProgress
		callbacks.push_update_reference = checkPushAccepted
		self.repository.remotes["origin"].push(["+{}:{}".format(self.localBranchReference(branchName), "refs/heads/{}".format(self.branches[branchName]))], callbacks = callbacks)
		printProgressBar("Pushing changes to the repository", 1, 1, overwrite = True)

	def writeStatus(self, message):
		statusFilePath = self.path("status", "status.log")

		if os.path.exists(statusFilePath):
			with open(statusFilePath, "r") as statusFile:
				# add the previous status messages, but trancate them
				content = statusFile.readlines()[0:(self.statusLogSize - 1)]
		else:
			content = ""

		with open(statusFilePath, "w") as statusFile:
			print("{}\t{}\n{}".format(time.strftime("%Y-%m-%d %H:%M:%S %z"), message, "".join(content)), file = statusFile, end = "")

		self.commit("status", "test status", ["status.log"])
		self.push("status")