require "uuid"
require "uri"
require "file_utils"

require "./context.cr"
require "./package.cr"
require "./instructions.cr"
require "./sources.cr"

# 🤔
class URI
	def basename
		File.basename path
	end
end

class Package::Recipe
	@context : Context

	# Core recipe informations.
	getter name          : String
	getter version       : String
	getter release       = 1

	property url         : String?
	property description : String = ""

	# Informations not specific to individual packages.
	getter sources       : Sources
	getter packages      : Array(Package)

	property packager    : String?
	property maintainer  : String?
	getter contributors  = Array(String).new

	# Relations to other packages.
	# FIXME: `dependencies` needs splitting between run-time and build-time.
	getter dependencies  = Array(String).new
	getter provides      = Array(String).new
	getter conflicts     = Array(String).new

	# Build instructions, helpers and other build-only data.
	setter dirname       : String? # matching getter defined manually later.
	getter instructions  = Instructions.new

	def initialize(@context, @name, @version)
		@sources = Sources.new
		@packages = [] of Package

		@working_uuid = UUID.random
	end

	def self.new(context, name, version)
		instance = Recipe.allocate.tap &.initialize(context, name, version)

		instance.packages << Package.new instance

		instance
	end

	def working_directory
		"#{@context.working_directory}/#{@working_uuid}"
	end

	def building_directory
		"#{working_directory}/build"
	end

	def fake_root_directory
		@packages[0].fake_root_directory
	end

	def dirname
		@dirname || "#{name}-#{version}"
	end

	def download : Bool
		sources
			.compact_map do |url|
				unless File.exists? url.basename
					@context.run @context.sources_directory, "wget", [ url.to_s, "-O", url.basename ]
				end
			end
			.map(&.success?)
			.reduce(true) { |a, b| a && b }
	end

	def extract : Bool
		Dir.mkdir_p building_directory

		sources
			.map do |url|
				basename = url.basename

				@context.run building_directory, "tar", [ "xvf", @context.sources_directory + "/" + url.basename ]
			end
			.map(&.success?)
			.reduce true { |a, b| a && b }
	end

	# TODO:
	#   - Export packaging directory in $PKG.
	#   - Add (pre|post)-(configure|build|install) instructions.
	#   - Have some instructions be non-critical, like the (pre|post] ones.
	#   - Be careful about return values, flee from everything if something
	#     goes somehow wrong.
	#   - Make things thread-safe. (those ENV[]= calls are definitely not)
	def build : Bool
		success = true

		Dir.mkdir_p fake_root_directory

		ENV["PKG"] = fake_root_directory

		# Safety precautions.
		old_dir = Dir.current

		instructions.to_a.each do |instruction|
			if instruction.run(@context, self).failed?
				break BuildStatus::Failed
			end
		end

		Dir.cd old_dir

		ENV["PKG"] = nil

		do_splits

		success
	end

	private def do_splits
		@packages.each do |package|
			next if package == @packages[0]

			files = package.files

			next if files.nil? # Should only happen to @packages[0].
			# TODO: ↑ add public APIs that ensure it.

			# FIXME: What do we do if those are not on the filesystem?
			files.each do |file|
				origin = "#{fake_root_directory}#{file}"
				destination ="#{package.fake_root_directory}#{file}"

				next unless File.exists? origin

				Dir.mkdir_p File.dirname destination

				FileUtils.mv(
					"#{fake_root_directory}#{file}",
					"#{package.fake_root_directory}#{file}"
				)

				puts file
				@context.run "find", [
					"#{package.fake_root_directory}/#{file}"
				]
			end
		end
	end

	def auto_split
		@context.splitter_backends.each do |backend|
			@packages << backend.create_split self
		end
	end

	# TODO:
	#  - Errors management. Stop at first failure?
	#  - Splits. This should be done between #build and #package.
	def package : Bool
		# This tries to build them all and stops at the first failure
		# (failures are currently reported by Context#package)
		@packages
			.find do |package|
				if package.automatic && ! File.exists? package.fake_root_directory
					next
				end

				! @context.package package
			end
			.== nil
	end

	def clean
		FileUtils.rm_rf building_directory
		FileUtils.rm_rf fake_root_directory
	end

	def to_s
		"#{name}-#{version}"
	end
end