fs = require "fs"
spawn = require("child_process").spawn
exec = require("child_process").exec
rimraf = require "rimraf"
Path = require "path"
semver = require "semver"
knox = require "knox"

SERVICES = [{
	name: "web"
	repo: "https://github.com/sharelatex/web-sharelatex.git"
}, {
	name: "document-updater"
	repo: "https://github.com/sharelatex/document-updater-sharelatex.git"
}, {
	name: "clsi"
	repo: "https://github.com/sharelatex/clsi-sharelatex.git"
}, {
	name: "filestore"
	repo: "https://github.com/sharelatex/filestore-sharelatex.git"
}, {
	name: "track-changes"
	repo: "https://github.com/sharelatex/track-changes-sharelatex.git"
}]

module.exports = (grunt) ->
	grunt.loadNpmTasks 'grunt-bunyan'
	grunt.loadNpmTasks 'grunt-execute'
	grunt.loadNpmTasks 'grunt-available-tasks'
	grunt.loadNpmTasks 'grunt-concurrent'

	execute = {}
	for service in SERVICES
		execute[service.name] =
			src: "#{service.name}/app.js"

	grunt.initConfig
		execute: execute

		concurrent:
			all:
				tasks: ("run:#{service.name}" for service in SERVICES)
				options:
					limit: SERVICES.length
					logConcurrentOutput: true

		availabletasks:
			tasks:
				options:
					filter: 'exclude',
					tasks: [
						'concurrent'
						'execute'
						'bunyan'
						'availabletasks'
						]
					groups:
						"Run tasks": [
							"run"
							"run:all"
							"default"
						].concat ("run:#{service.name}" for service in SERVICES)
						"Misc": [
							"help"
						]
						"Install tasks": ("install:#{service.name}" for service in SERVICES).concat(["install:all", "install", "install:config"])
						"Update tasks": ("update:#{service.name}" for service in SERVICES).concat(["update:all", "update"])
						"Config tasks": ["install:config"]
						"Checks": ["check", "check:redis", "check:latexmk", "check:s3", "check:make"]

	for service in SERVICES
		do (service) ->
			grunt.registerTask "install:#{service.name}", "Download and set up the #{service.name} service", () ->
				done = @async()
				Helpers.installService(service.repo, service.name, done)
			grunt.registerTask "update:#{service.name}", "Checkout and update the #{service.name} service", () ->
				done = @async()
				Helpers.updateService(service.name, done)
			grunt.registerTask "run:#{service.name}", "Run the ShareLaTeX #{service.name} service", ["bunyan", "execute:#{service.name}"]

	grunt.registerTask 'install:config', "Copy the example config into the real config", () ->
		Helpers.installConfig @async()
	grunt.registerTask 'install:all', "Download and set up all ShareLaTeX services",
		["check:make"].concat(
			("install:#{service.name}" for service in SERVICES)
		).concat(["install:config"])
	grunt.registerTask 'install', 'install:all'
	grunt.registerTask 'update:all', "Checkout and update all ShareLaTeX services",
		["check:make"].concat(
			("update:#{service.name}" for service in SERVICES)
		)
	grunt.registerTask 'update', 'update:all'
	grunt.registerTask 'run', "Run all of the sharelatex processes", ['concurrent:all']
	grunt.registerTask 'run:all', 'run'

	grunt.registerTask 'help', 'Display this help list', 'availabletasks'
	grunt.registerTask 'default', 'run'

	grunt.registerTask "check:redis", "Check that redis is installed and running", () ->
		Helpers.checkRedis @async()
	grunt.registerTask "check:latexmk", "Check that latexmk is installed", () ->
		Helpers.checkLatexmk @async()
	grunt.registerTask "check:s3", "Check that Amazon S3 credentials are configured", () ->
		Helpers.checkS3 @async()
	grunt.registerTask "check:fs", "Check that local filesystem options are configured", () ->
		Helpers.checkFS @async()
	grunt.registerTask "check:make", "Check that make is installed", () ->
		Helpers.checkMake @async()
	grunt.registerTask "check", "Check that you have the required dependencies installed", ["check:redis", "check:latexmk", "check:s3", "check:fs"]

	Helpers =
		installService: (repo_src, dir, callback = (error) ->) ->
			Helpers.cloneGitRepo repo_src, dir, (error) ->
				return callback(error) if error?
				Helpers.installNpmModules dir, (error) ->
					return callback(error) if error?
					Helpers.runGruntInstall dir, (error) ->
						return callback(error) if error?
						callback()

		updateService: (dir, callback = (error) ->) ->
			Helpers.updateGitRepo dir, (error) ->
				return callback(error) if error?
				Helpers.installNpmModules dir, (error) ->
					return callback(error) if error?
					Helpers.runGruntInstall dir, (error) ->
						return callback(error) if error?
						callback()

		cloneGitRepo: (repo_src, dir, callback = (error) ->) ->
			if !fs.existsSync(dir)
				proc = spawn "git", ["clone", repo_src, dir], stdio: "inherit"
				proc.on "close", () ->
					callback()
			else
				console.log "#{dir} already installed, skipping."
				callback()

		updateGitRepo: (dir, callback = (error) ->) ->
			proc = spawn "git", ["checkout", "master"], cwd: dir, stdio: "inherit"
			proc.on "close", () ->
				proc = spawn "git", ["pull"], cwd: dir, stdio: "inherit"
				proc.on "close", () ->
					callback()

		installNpmModules: (dir, callback = (error) ->) ->
			proc = spawn "npm", ["install"], stdio: "inherit", cwd: dir
			proc.on "close", () ->
				callback()

		installConfig: (callback = (error) ->) ->
			if !fs.existsSync("config/settings.development.coffee")
				grunt.log.writeln "Copying example config into config/settings.development.coffee"
				exec "cp config/settings.development.coffee.example config/settings.development.coffee", (error, stdout, stderr) ->
					callback(error)
			else
				grunt.log.writeln "Config file already exists. Skipping."
				callback()

		runGruntInstall: (dir, callback = (error) ->) ->
			proc = spawn "grunt", ["install"], stdio: "inherit", cwd: dir
			proc.on "close", () ->
				callback()

		checkRedis: (callback = (error) ->) ->
			grunt.log.write "Checking Redis is running... "
			exec "redis-cli info", (error, stdout, stderr) ->
				if error? and error.message.match("Could not connect")
					grunt.log.error "FAIL. Redis is not running"
					return callback(error)
				else if error?
					return callback(error)
				else
					m = stdout.match(/redis_version:(.*)/)
					if !m?
						grunt.log.error "FAIL."
						grunt.log.error "Unknown redis version"
						error = new Error("Unknown redis version")
					else
						version = m[1]
						if semver.gt(version, "2.6.0")
							grunt.log.writeln "OK."
							grunt.log.writeln "Running Redis version #{version}"
						else
							grunt.log.error "FAIL."
							grunt.log.error "Redis version is too old (#{version}). Must be 2.6.0 or greater."
							error = new Error("Redis version is too old (#{version}). Must be 2.6.0 or greater.")
				callback(error)

		checkLatexmk: (callback = (error) ->) ->
			grunt.log.write "Checking latexmk is installed... "
			exec "latexmk --version", (error, stdout, stderr) ->
				if error? and error.message.match("command not found")
					grunt.log.error "FAIL."
					grunt.log.errorlns """
					Either latexmk is not installed or is not in your PATH.

					latexmk comes with TexLive 2013, and must be a version from 2013 or later.
					This is a not a fatal error, but compiling will not work without latexmk
					"""
					return callback(error)
				else if error?
					return callback(error)
				else
					m = stdout.match(/Version (.*)/)
					if !m?
						grunt.log.error "FAIL."
						grunt.log.error "Unknown latexmk version"
						error = new Error("Unknown latexmk version")
					else
						version = m[1]
						if semver.gte(version + ".0", "4.39.0")
							grunt.log.writeln "OK."
							grunt.log.writeln "Running latexmk version #{version}"
						else
							grunt.log.error "FAIL."
							grunt.log.errorlns """
							latexmk version is too old (#{version}). Must be 4.39 or greater.
							This is a not a fatal error, but compiling will not work without latexmk
							"""
							error = new Error("latexmk is too old")
				callback(error)

		checkS3: (callback = (error) ->) ->
			Settings = require "settings-sharelatex"
			if Settings.filestore.backend==""
				grunt.log.writeln "No backend specified. Assuming Amazon S3"
				Settings.filestore.backend = "s3"
			if Settings.filestore.backend=="s3"
				grunt.log.write "Checking S3 credentials... "
				try
					client = knox.createClient({
						key: Settings.filestore.s3.key
						secret: Settings.filestore.s3.secret
						bucket: Settings.filestore.stores.user_files
					})
				catch e
					grunt.log.error "FAIL."
					grunt.log.errorlns """
					Please configure your Amazon S3 credentials in config/settings.development.coffee

					Amazon S3 (Simple Storage Service) is a cloud storage service provided by
					Amazon. ShareLaTeX uses S3 for storing binary files like images. You can 
					sign up for an account and find out more at:

							http://aws.amazon.com/s3/
										
					"""
					return callback()
				client.getFile "does-not-exist", (error, response) ->
					unless response? and response.statusCode == 404
						grunt.log.error "FAIL."
						grunt.log.errorlns """
						Could not connect to Amazon S3. Please check your credentials.
						"""
					else
						grunt.log.write "OK."
					callback()
			else
				grunt.log.writeln "Filestore other than S3 configured. Not checking S3."
				callback()

		checkFS: (callback = (error) ->) ->
			Settings = require "settings-sharelatex"
			if Settings.filestore.backend=="fs"
				grunt.log.write "Checking FS configuration..."
				fs = require("fs")
				fs.exists Settings.filestore.stores.user_files, (exists) ->
					if exists
						grunt.log.write "OK."
					else
						grunt.log.error "FAIL."
						grunt.log.errorlns """
						Could not find directory "#{Settings.filestore.stores.user_files}". 
						Please check your configuration.
						"""
			else
				grunt.log.writeln "Filestore other than FS configured. Not checking FS."
			callback()


		checkMake: (callback = (error) ->) ->
			grunt.log.write "Checking make is installed... "
			exec "make --version", (error, stdout, stderr) ->
				if error? and error.message.match("command not found")
					grunt.log.error "FAIL."
					grunt.log.errorlns """
					Either make is not installed or is not in your path.

					On Ubuntu you can install make with:

					    sudo apt-get install build-essential

					"""
					return callback(error)
				else if error?
					return callback(error)
				else
					grunt.log.write "OK."
					return callback()