#!/usr/bin/env ruby
#
# Copyright (c) 2009-2010 Giorgio Gonnella <gonnella@zbh.uni-hamburg.de>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#

require "erb"
$CONFIG = ENV["GT_CODEGEN_CONFIG"] || "~/.gitconfig"

$help = <<-END_HELP
\nCode generator for:
- header file (license, ifndef/def/endif)
- module files (header file and c file including the header)
- class files (h and c files, basic skeleton)
- tool files (based on tools/gt_template.[ch])

It requires name and email of the user, that are expected
to be found in the [user] section of the user-specific git
configuration file (#$CONFIG). You may specify another file
using the env variable GT_CODEGEN_CONFIG.

Usage:

  #$0 header|module|class|tool <subdir> <basename>

where <subdir> is the directory under src where the files are written
and <basename> has no gt_ prefix and is written in lower case,
and if it consists of multiple words they are connected_with_underscores
e.g.
  #$0 tool tools xyz
  #$0 header core abc_def

There is absolutely no guarantee that the results are correct.
Existing files are not overwritten or modified.
Report bugs to <gonnella@zbh.uni-hamburg.de>.
END_HELP

$license = <<-END_LICENSE
/*
  Copyright (c) <%=year%> <%=name%> <<%=email%>>
  Copyright (c) <%=year%> Center for Bioinformatics, University of Hamburg

  Permission to use, copy, modify, and distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
END_LICENSE

$hwrapper = <<-END_HWRAPPER
#ifndef <%=guard_macro%>
#define <%=guard_macro%>
<%=content%>
#endif
END_HWRAPPER

$gt_class_c = <<-END_GT_CLASS_C

#include "core/ma.h"

struct <%=klass%>
{
};

<%=creatordecl%>
{
  <%=klass%> *<%=basename%>;
  <%=basename%> = gt_malloc(sizeof (<%=klass%>));
  return <%=basename%>;
}

<%=destructordecl%>
{
  gt_free(<%=basename%>);
}
END_GT_CLASS_C

$gt_class_h = <<-END_GT_CLASS_H

typedef struct <%=klass%> <%=klass%>;

<%=creatordecl%>;
<%=destructordecl%>;
END_GT_CLASS_H

def perror(msg)
  STDERR.puts "#$0: error: #{msg}"
  STDERR.puts "Use '#$0 help' to print usage instructions"
  exit(1)
end

def find_user_data
  configfile = File.expand_path($CONFIG)
  if File.exist?(configfile)
    name = nil
    email = nil
    File.open(configfile) do |f|
      while (line = f.gets) && (!name||!email) do
        name = $1  if !name  && line =~ /\s*name\s*=\s*(.*)\s*\n/
        email = $1 if !email && line =~ /\s*email\s*=\s*(.*)\s*\n/
      end
    end
    return name, email
  else
    perror("#$CONFIG file not found")
  end
end

def find_src_directory
  scripts_dir = File.dirname(File.expand_path($0))
  src_dir = File.join(scripts_dir, "..", "src")
  return File.expand_path(src_dir)
end

def parse_args
  generators = %w{header module class tool help}
  perror("not enough arguments") if ARGV.size < 1
  generator = ARGV[0]
  if (generator=="help")
    puts($help)
    exit(0)
  end
  perror("generator #{generator} unknown") if !generators.include?(generator)
  perror("not enough arguments") if ARGV.size < 3
  perror("too many arguments") if ARGV.size > 3
  path = File.join(find_src_directory, ARGV[1])
  perror("Directory #{path} not found") if !File.directory?(path)
  basename = ARGV[2]
  return generator, path, basename
end

def check_file(path, basename, extension)
  filename = File.join(path, basename+"."+extension)
  perror("File #{filename} exists already") if File.exist?(filename)
end

def write_file(path, basename, extension, content)
  filename = File.join(path, basename+"."+extension)
  file = File.open(filename, "w+")
  puts File.expand_path(file.path)
  file.puts(content)
  file.close
end

def gen_header(path, basename, content = "")
  guard_macro = basename.upcase+"_H"
  header = $license + "\n" + ERB.new($hwrapper).result(binding)
  check_file(path, basename, "h")
  write_file(path, basename, "h", header)
end

def gen_module(path, basename, ccontent = "\n", hcontent = "")
  code = $license + "\n" +
         "#include \"#{File.basename(path)}/#{basename}.h\"" +
         ccontent
  check_file(path, basename, "c")
  gen_header(path, basename, hcontent)
  write_file(path, basename, "c", code)
end

def gen_class(path, basename)
  prefix = "gt_#{basename}_"
  klass = "Gt"+basename.gsub(/(^|_)(.)/){$2.upcase}
  creatordecl = "#{klass} *#{prefix}new(void)"
  destructordecl = "void #{prefix}delete(#{klass} *#{basename})"
  gen_module(path, basename,
             ERB.new($gt_class_c).result(binding),
             ERB.new($gt_class_h).result(binding))
end

def prepare_tool_c(path, basename)
  tools_dir = File.join(find_src_directory, "tools")
  gt_template_c = File.expand_path(File.join(tools_dir, "gt_template.c"))
  perror("File #{gt_template_c} not found") if !File.exists?(gt_template_c)
  # skip license template:
  c_template = IO.read(gt_template_c)
  c_template =~ /(.*?)(#include.*)/m
  c_template = $2
  structprefix = "Gt"+basename.gsub(/(^|_)(.)/){$2.upcase}
  c_template.gsub!("template", basename)
  c_template.gsub!("Template", structprefix)
  return $license + "\n" + c_template
end

def prepare_tool_h(path, basename)
  tools_dir = File.join(find_src_directory, "tools")
  gt_template_h = File.expand_path(File.join(tools_dir, "gt_template.h"))
  perror("File #{gt_template_h} not found") if !File.exists?(gt_template_h)
  h_template = IO.read(gt_template_h)
  # skip license template:
  h_template =~ /(.*?)(#ifndef.*)/m
  h_template = $2
  h_template.gsub!("TEMPLATE", basename.upcase)
  h_template.gsub!("template", basename)
  return $license + "\n" + h_template
end

def gen_tool(path, basename)
  check_file(path, "gt_"+basename, "h")
  check_file(path, "gt_"+basename, "c")
  write_file(path, "gt_"+basename, "h", prepare_tool_h(path, basename))
  write_file(path, "gt_"+basename, "c", prepare_tool_c(path, basename))
end

# main
generator, path, basename = parse_args
name, email = find_user_data
year = Time.now.year
$license = ERB.new($license).result
send("gen_#{generator}", path, basename)
