#!/usr/bin/env bash
########################################################################
# Copyright 2014 Lukas Bestle <project-projectr@lukasbestle.com>
# License   MIT
########################################################################
# Clones the repository of a project from the server, runs the script
# .postdeploy.sh in the repository (if existing) and links the version
# as current.
#
# Usage: project_deploy <project> [<revision>]
#        
#        <project>   Path to the project
#        <revision>  SHA-1 commit hash of the revision to checkout
#                    Defaults to the latest commit on the set branch.
########################################################################
# Functions

# Reverses changes
function project_deploy::reverse() {
	local project="$1"
	local destination="$2"
	local shiftLinks=$3
	
	echo -e "\033[1mReversing changes...\033[0m"
	
	# Remove destination directory
	rm -Rf "$destination"
	
	# Shift links back to their old state
	if [[ $shiftLinks == true ]]; then
		rm -f "$project/current"
		if [[ -e "$project/last" ]]; then
			mv "$project/last" "$project/current"
		fi
	fi
}

# Builds the paths to a version
declare directoryCount versionNumber versionName destinationRelative destination
function project_deploy::buildVersionPath() {
	destinationRelative="versions/$versionName"
	destination="$(cd "$project" && echo -n "$(pwd)/$destinationRelative")"
}

########################################################################

project="$1"
revision="${2:-latest}"

# Load configuration
CONFIG_PRESERVE_VERSIONS=5
CONFIG_HASH_LENGTH=40
if [[ -f "$HOME/.project.cnf" ]]; then
	source "$HOME/.project.cnf"
fi
if [[ $CONFIG_PRESERVE_VERSIONS == 1 ]]; then
	echo -e "\033[31mThe value of \033[34m\$CONFIG_PRESERVE_VERSIONS\033[31m is too low (\033[34m1\033[31m), setting it to \033[34m2\033[31m.\033[0m" >&2
	CONFIG_PRESERVE_VERSIONS=2
fi

if [[ -z "$project" ]]; then
	# Print help
	echo -e "\033[1mUsage:\033[0m \033[34mproject_deploy\033[0m <project> [<revision>]"
	exit 1
fi

# Check if the default value for $CONFIG_HASH_LENGTH has been changed
if [[ "$revision" == "latest" ]] && [[ $CONFIG_HASH_LENGTH != 40 ]]; then
	echo -e "\033[31mYou have changed the default value of \033[34m\$CONFIG_HASH_LENGTH\033[31m. To make sure the deployed revisions are unique and never duplicated, deployments of the latest revision aren't supported with a custom value of this option. Please give me the exact revision string in your custom length.\033[0m" >&2
	exit 1
fi

# Check if the project exists
if [[ ! -f "$project/.project" ]]; then
	echo -e "\033[31mThe project \033[34m$project\033[31m does not exist or is invalid.\033[0m" >&2
	exit 1
fi

# Check if the project can be updated
if [[ ! -f "$project/.origin" ]]; then
	echo -e "\033[31mThe project \033[34m$project\033[31m is not deployable.\033[0m" >&2
	exit 1
fi

# Add header to log
log="$project/logs/$revision.log"
if [[ -f "$log" ]]; then
	# Separator between multiple logs
	echo -e "\033[1;35m======\033[0m" >> "$log"
fi
echo -e "\033[1;35mRun on \033[34m$(date)\033[35m by \033[34m$USER\033[35m:\n------\033[0m" >> "$log"

# Log everything beginning here
{
	# Make sure the repository exists and is updated
	# We only need to do this if the revision was not deployed yet
	if ! ls "$project/versions"/*-$revision &> /dev/null; then
		# Check if the repository has already been cloned
		url="$(cat "$project/.origin")"
		if ! [[ -d "$project/repo" ]]; then
			# No, clone it now
			echo -e "\033[1mCloning from \033[34m$url\033[0;1m for the first time...\033[0m"
			if ! git clone --recursive "$url" "$project/repo"; then
				echo -e " => \033[31mCould not clone project \033[34m$project\033[31m from \033[34m$url\033[31m.\033[0m" >&2
				exit 1
			fi
			echo -e " => \033[32mSuccess.\033[0m"
		else
			# Yes, only fetch from the remote repository
			echo -e "\033[1mFetching new commits from \033[34m$url\033[0;1m...\033[0m"
			if ! (git -C "$project/repo" fetch); then
				echo -e " => \033[31mCould not fetch from \033[34m$url\033[31m.\033[0m" >&2
				exit 1
			fi
			echo -e " => \033[32mSuccess.\033[0m"
		fi
	fi
	
	# Determine the actual revision to use
	if [[ "$revision" != "latest" ]]; then
		# Check if the given commit hash is valid
		if [[ ${#revision} != $CONFIG_HASH_LENGTH ]]; then
			echo -e "\033[31mThe length of the revision name \033[34m$revision\033[31m is not equal to the configured \033[34m$CONFIG_HASH_LENGTH\033[31m characters.\033[0m" >&2
			exit 1
		fi
	else
		# Check if the set branch exists
		branch="$(cat "$project/.branch")"
		echo -e "\033[1mDetermining current revision for branch \033[34m$branch\033[0;1m...\033[0m"
		if ! (git -C "$project/repo" show-branch "$branch" &> /dev/null); then
			echo -e " => \033[31mThe set branch \033[34m$branch\033[31m does not exist.\033[0m" >&2
			exit 1
		fi
		
		# Get the commit hash from the set branch
		revision="$(git -C "$project/repo" rev-list --max-count=1 "origin/$branch")"
		if [[ $? != 0 ]]; then
			echo -e " => \033[31mCould not determine current revision.\033[0m" >&2
			exit 1
		fi
		
		echo -e " => \033[32mUsing revision \033[34m$revision\033[32m.\033[0m"
	fi
	
	# Check if we already installed this version
	if ls "$project/versions"/*-$revision &> /dev/null; then
		# Yes, use that
		
		# Build the pathname of the destination directory
		versionName="$(basename "$(echo "$project/versions"/*-$revision)")"
		project_deploy::buildVersionPath
		
		echo -e "\033[1mThis revision has already been installed, using previous installation \033[34m$versionName\033[0;1m.\033[0m"
	else
		# No, fetch and install
		
		# Build the pathname of the destination directory
		# Get all version names, get the last one, split it by "-" and get the first part, remove leading zeros
		latestVersion=$(echo "$(ls "$project/versions" | tail -1)" | cut -f1 -d- | sed 's/^0*//')
		versionNumber=$(($latestVersion + 1)) # Next is +1
		versionName="$(printf "%05d" "$versionNumber")-$revision"
		project_deploy::buildVersionPath
		
		# Copy repository to new destination
		echo -e "\033[1mCopying repository to deployment destination...\033[0m"
		if ! cp -R "$project/repo" "$destination"; then
			echo -e " => \033[31mCould not copy repository.\033[0m" >&2
			project_deploy::reverse "$project" "$destination"
			exit 1
		fi
		echo -e " => \033[32mSuccess.\033[0m"
		
		# Checkout correct revision
		echo -e "\033[1mChecking out revision \033[34m$revision\033[0;1m...\033[0m"
		if ! git -C "$destination" checkout "$revision"; then
			echo -e " => \033[31mCould not checkout revision \033[34m$revision\033[31m of project \033[34m$project\033[31m.\033[0m" >&2
			project_deploy::reverse "$project" "$destination"
			exit 1
		fi
		echo -e " => \033[32mSuccess.\033[0m"
		
		# Update submodules
		echo -e "\033[1mUpdating submodules...\033[0m"
		if ! git -C "$destination" submodule update --init --recursive; then
			echo -e " => \033[31mCould not update submodules of project \033[34m$project\033[31m.\033[0m" >&2
			project_deploy::reverse "$project" "$destination"
			exit 1
		fi
		echo -e " => \033[32mSuccess.\033[0m"
		
		# Run post-deploy script if existing
		if [[ -x "$destination/.postdeploy.sh" ]]; then
			# Set the working directory to the destination
			oldpwd="$(pwd)"
			cd "$destination"
			
			echo -e "\033[1mRunning post-deploy script...\033[0m"
			if ! $destination/.postdeploy.sh; then
				echo -e " => \033[31mSomething went wrong.\033[0m" >&2
				project_deploy::reverse "$project" "$destination"
				exit 1
			fi
			echo -e " => \033[32mSuccess.\033[0m"
			
			cd "$oldpwd"
		fi
		
		# Remove .git directory
		echo -e "\033[1mDeleting \033[34m.git\033[0;1m directory...\033[0m"
		if ! rm -Rf "$destination/.git"; then
			echo -e " => \033[31mCould not delete \033[34m.git\033[31m directory.\033[0m" >&2
			project_deploy::reverse "$project" "$destination"
			exit 1
		fi
		echo -e " => \033[32mSuccess.\033[0m"
		
		# Clean up old versions
		if [[ $CONFIG_PRESERVE_VERSIONS -gt 0 ]]; then
			echo -e "\033[1mCleaning up old versions...\033[0m"
			# Delete the first version until there are $CONFIG_PRESERVE_VERSIONS versions
			while [[ $(ls -q "$project/versions" | wc -l) -gt $CONFIG_PRESERVE_VERSIONS ]]; do
				item="$(ls -d "$project/versions"/* | head -1)"
				echo -e " - Deleting \033[34m$item\033[0m..."
				rm -Rf "$item"
			done
			echo -e " => \033[32mSuccess.\033[0m"
		else
			echo -e "\033[1;31mNot\033[0;1m cleaning up old versions (disabled in configuration).\033[0m"
		fi
	fi
	
	# Create symlinks to current version
	echo -e "\033[1mSymlinking new version...\033[0m"
	# Remove old symlink
	if ! rm -f "$project/last"; then
		echo -e " => \033[31mCould not delete old link.\033[0m" >&2
		project_deploy::reverse "$project" "$destination"
		exit 1
	fi
	# Move current symlink to old symlink
	if [[ -e "$project/current" ]]; then
		if ! mv "$project/current" "$project/last"; then
			echo -e " => \033[31mCould not shift current link to old link.\033[0m" >&2
			project_deploy::reverse "$project" "$destination"
			exit 1
		fi
	fi
	# Create new symlink
	if ! ln -s "$destinationRelative" "$project/current"; then
		echo -e " => \033[31mCould not create new link.\033[0m" >&2
		project_deploy::reverse "$project" "$destination" true
		exit 1
	fi
	echo -e " => \033[32mSuccess.\033[0m"
	
} 2>&1 | tee -a "$log" # Duplicate output to log file