#!/usr/bin/make -f

#
# \brief  Tool for downloading and patching 3rd-party source code
# \author Norman Feske
# \date   2014-05-07
#

VERBOSE ?= @
ECHO    := echo -e

#
# Always execute the $(TARGET) rule regardless of the supplied command-line
# argument
#
TARGET := $(MAKECMDGOALS) default
$(MAKECMDGOALS) default:

# the single argument is the name of the port to prepare
ARGUMENT  := $(MAKECMDGOALS)
PORT_NAME := $(firstword $(ARGUMENT))

#
# Determine Genode base directory based on the known location of the
# 'create_builddir' tool within the Genode source tree
#
GENODE_DIR ?= $(realpath $(dir $(MAKEFILE_LIST))/../..)

# compound directory where all 3rd-party source codes are installed
CONTRIB_DIR ?= $(GENODE_DIR)/contrib

# list of all repositories located at '<genode-dir>/repos/'
REPOSITORIES ?= $(shell find $(GENODE_DIR)/repos -follow -mindepth 1 -maxdepth 1 -type d)

# list of all repositories that contain ports of 3rd-party source code
_REP_PORTS_DIRS := $(wildcard $(addsuffix /ports,$(REPOSITORIES)))

# list of all available ports
_PORTS := $(foreach DIR,$(_REP_PORTS_DIRS),$(wildcard $(DIR)/*.port))

# port file to use
PORT := $(filter %/$(PORT_NAME).port,$(_PORTS))

# repository that contains the port description, used to look up patch files
REP_DIR := $(realpath $(dir $(PORT))/..)

# read hash that uniquely identifies the version to install
HASH_FILE := $(wildcard $(PORT:.port=.hash))
HASH      := $(if $(HASH_FILE),$(shell cat $(HASH_FILE)),)

# path to hash file relative to '<genode-dir>/repos', used for error messages
_REL_HASH_FILE := $(notdir $(REP_DIR))/ports/$(notdir $(PORT))

# directory where to install the port
PORT_DIR := $(CONTRIB_DIR)/$(PORT_NAME)-$(HASH)

# path to hash file generated during installation
PORT_HASH_FILE := $(PORT_DIR)/$(PORT_NAME).hash

#
# Check validity of user input
#
ifeq ($(ARGUMENT),)
$(TARGET): missing_argument
missing_argument: usage
	@$(ECHO) "Error: Missing port name as argument"; false
endif

ifneq ($(words $(ARGUMENT)),1)
$(TARGET): too_many_arguments
too_many_arguments: usage
	@$(ECHO) "Error: Too many arguments specified, expecting one argument"; false
endif

ifeq ($(PORT),)
$(TARGET): nonexisting_port
nonexisting_port:
	@$(ECHO) "Error: Port $(PORT_NAME) does not exist"; false
endif

ifeq ($(HASH),)
$(TARGET): nonexisting_hash
nonexisting_hash:
	@$(ECHO) "Error: Port $(PORT_NAME) lacks a valid hash"; false
endif

usage:
	@$(ECHO)
	@$(ECHO) "--- download and patch 3rd-party source code ---"
	@$(ECHO) "usage: prepare_port <port-name> [CHECK_HASH=no]"
	@$(ECHO)

#
# Default rule that triggers the actual preparation steps
#
$(TARGET): _check_integrity

_check_integrity : _install_in_port_dir
ifneq ($(CHECK_HASH),no)
	$(VERBOSE)diff $(PORT_HASH_FILE) $(HASH_FILE) > /dev/null ||\
		($(ECHO) "Error: $(_REL_HASH_FILE) is out of date, expected" `cat $(PORT_HASH_FILE)` ""; false)
endif

#
# During the preparatio steps, the port directory is renamed. We use the suffix
# ".incomplete" to mark this transient state of the port directory.
#
_install_in_port_dir: $(PORT_DIR)
	@#\
	 # if the transient directory already exists, reuse it as it may contain\
	 # finished steps such as downloads. By reusing it, we avoid downloading\
	 # the same files again and again while working on a port. However, in this\
	 # case, we already have created an empty port directory via the $(PORT_DIR)\
	 # rule below. To avoid having both the port directory and the transient\
	 # port directory present, remove the just-created port directory.\
	 #
	$(VERBOSE)(test -d $(PORT_DIR).incomplete && rmdir $(PORT_DIR)) || true
	@#\
	 # If no transient directory exists, rename the port directory accordingly.\
	 #
	$(VERBOSE)test -d $(PORT_DIR).incomplete || mv --force $(PORT_DIR) $(PORT_DIR).incomplete
	$(VERBOSE)$(MAKE) --no-print-directory \
	                  -f $(GENODE_DIR)/tool/ports/mk/install.mk \
	                  -C $(PORT_DIR).incomplete \
	                  PORT=$(PORT) VERBOSE=$(VERBOSE)
	@#\
	 # The preparation finished successfully. So we can rename the transient\
	 # directory to the real one.\
	 #
	$(VERBOSE)mv $(PORT_DIR).incomplete $(PORT_DIR)

$(PORT_DIR):
	$(VERBOSE)mkdir -p $@