#!/usr/bin/env ruby

require 'como'
include Como
require 'rubu'
include Rubu

require 'fileutils'


Spec.command( 'rubu_example', 'Tero Isannainen', '2018',
    [
        [ :opt_multi, 'conf',    '-c', "Configuration option." ],
        [ :switch,    'verbose', '-v', "Verbose." ],
        [ :switch,    'serial',  '-s', "Serial execution." ],
        [ :default,    nil,       nil, "Trail(s) to execute." ],
    ] )



# ------------------------------------------------------------
# Build specific definitions:

# Set trail related options.
Var[ :bin_dir ]    = 'bin'
Var[ :source_dir ] = 'src'
Var[ :gen_dir ]    = 'gen_cee'
Var[ :build_dir ]  = 'build'
Var[ :exe_name ]   = 'build/hello'

# Default for :fast option.
Var[ :fast ] = false

# Change Rubu to verbose mode.
if Opt['verbose'].given
    Order[ :verbose ] = true
end

# Force serial execution.
if Opt[ 'serial' ].given
    Order[ :serial ] = true
end

# Read setup files and apply Como command line arguments to Var space.
Trail.setup( :como => 'conf' )


# ------------------------------------------------------------
# Collect sources and create targets:

# Generator file and the target.
gen_file      = Mark.path( "#{Var[:bin_dir]}/gen_world" )
gen_cee_file  = Mark.path( "#{Var[:gen_dir]}/world.c" )

# Collect "normal" C files.
cee_files     = Mark.glob( "#{Var[:source_dir]}/*.c" )

# Create complete list of all C files.
all_cee_files = [ gen_cee_file ] + cee_files

# Convert C files to corresponding Object files.
obj_files     = all_cee_files.peer( Var[ :build_dir ], '.o' )

# Specify executable file.
exe_file      = Mark.path( Var[ :exe_name ] )


# Generate execution time information to Info. Used by CleanObjects.
Info[ :gen_files ] = [ gen_cee_file ]



# ------------------------------------------------------------
# Build Commands:

# Code generator with generated file dependency.
class GenWorld < Step
    def step
        shrun "bin/gen_world"
    end
end

# Code generator with generated file content dependency.
class GenGreenWorld < StepMark
    def step
        shrun "bin/gen_world"
    end
end


# Typical C compilation with GCC, from source to object.
class GccCompileFile < StepAged

    def setup
        @cmd = "gcc -Wall -I #{Var[:source_dir]} -c #{source.rpath} -o #{target.rpath}"

        # Compile with "-O2" if :fast is set.
        if Var[ :fast ]
            @cmd += " -O2"
        else
            @cmd += " -g"
        end
    end

    def step
        shrun @cmd
    end
end


# GCC linking.
class GccLinkExe < StepAged

    def setup
        @cmd  = "gcc #{sources.rpath} -o #{target.rpath}"
    end

    def step
        shrun @cmd
    end
end


# Cleaning.
class CleanObjects < Step

    def step
        # Multiple jobs are grouped with walk (serial execution).
        walk do
            shuse "rm -f #{Info[ :gen_files ].rpath}"
            shuse "rm -f #{Var[ :build_dir ]}/*.o"

            # Use Ruby for deleting the exe as an example.
            rbuse "rm -f #{Var[ :exe_name ]}" do
                FileUtils.rm_f Var[ :exe_name ]
            end
        end
    end
end


# ------------------------------------------------------------
# Define trails:

# Serial trail for code generation.
Walk.form 'gen-cee' do
    # Create GenWorld build and register it to 'gen-cee'.
    GenWorld.use( gen_file, gen_cee_file )
end

# Serial trail for code generation (with filtered updates).
Walk.form 'gen-cee-green' do
    # Create GenGreenWorld build and register it to 'gen-cee-green'.
    GenGreenWorld.use( gen_file, gen_cee_file )
end

# Parallel compilation of all C files.
Fork.form 'compile-cee' do
    # Create set of GCC builds by joining 'all_cee_files' and
    # 'obj_files' in pairs.
    GccCompileFile.usezip( all_cee_files, obj_files )
end

# Link executable.
Walk.form 'link' do
    GccLinkExe.use( obj_files, exe_file )
end

# Default trail, i.e. generate, compile, link to executable.
Walk.form 'default' do
    # Reference 'gen-cee' trail.
    pick 'gen-cee'
    # Reference 'compile-cee' trail.
    pick 'compile-cee'
    # Create GCC link build and register it.
    pick 'link'
end

# Trail for 'up-to-date' script (see: example dir).
Walk.form 'up-to-date' do
    # Reference 'gen-cee-green' trail.
    pick 'gen-cee-green'
    # Reference 'compile-cee' trail.
    pick 'compile-cee'
end

# Cleaner trail.
Walk.form 'clean' do
    CleanObjects.use
end



# ------------------------------------------------------------
# Run selected trails:

trails = nil
if Opt[ nil ].given
    trails = Opt[ nil ].value
else
    trails = [ 'default' ]
end

Trail.run( trails )