# Copyright (C) 2018 Apple Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
# THE POSSIBILITY OF SUCH DAMAGE.

require 'date'
require 'digest'

$LICENSE = <<-EOF
Copyright (C) #{Date.today.year} Apple Inc. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

1.  Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
2.  Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
EOF

module GeneratedFile
    class Template < Struct.new(:multiline_comment, :line_comment, :prefix, :suffix, :body)
        def initialize
            super(["/*", " *", "*/"], "// ", nil, nil, nil)
        end
    end

    def self.create(filename, *dependencies)
        template = Template.new
        yield template

        file = File.open(filename, "w")
        self.sha1(file, template, dependencies)
        self.license(file, template, dependencies)

        unless template.prefix.nil?
            write(file, template.prefix.to_s, "\n")
        end
        unless template.body.nil?
            write(file, template.body.to_s, "\n")
        end
        unless template.suffix.nil?
            write(file, template.suffix.to_s, "\n")
        end
    end

    def self.sha1(file, template, dependencies)
      write(file, template.line_comment, " SHA1Hash: ", Digest::SHA1.hexdigest(dependencies.join), "\n")
    end

    def self.license(file, template, dependencies)
        unless template.multiline_comment.nil?
            write(file, template.multiline_comment[0], "\n")
        end

        comment = if template.multiline_comment.nil? then template.line_comment else template.multiline_comment[1] end
        write(file, $LICENSE.strip.split("\n").map { |line| "#{comment} #{line}" }.join("\n"), "\n\n")
        write(file, comment, " Autogenerated, do not modify.\n")

        unless template.multiline_comment.nil?
            write(file, template.multiline_comment[2], "\n")
        end

        write(file, "\n")
    end

    def self.write(file, *strings)
        file.write(strings.map(&:to_s).join)
    end
end