# Copyright (C) 2011-2012 Tanaka Akira  <akr@fsij.org>
#
# 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.
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#     copyright notice, this list of conditions and the following
#     disclaimer in the documentation and/or other materials provided
#     with the distribution.
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#     products derived from this software without specific prior
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Tb::Cmd.subcommands << 'mheader'

Tb::Cmd.default_option[:opt_mheader_count] = nil

def (Tb::Cmd).op_mheader
  op = OptionParser.new
  op.banner = "Usage: tb mheader [OPTS] [TABLE]\n" +
    "Collapse multi rows header."
  define_common_option(op, "ho", "--no-pager")
  op.def_option('-c N', 'number of header records') {|arg| Tb::Cmd.opt_mheader_count = arg.to_i }
  op
end

Tb::Cmd.def_vhelp('mheader', <<'End')
Example:

  % cat tst.csv
  foo,foo,bar,bar
  baz,qux,baz,qux
  1,2,3,4
  5,6,7,8
  % tb mheader tst.csv
  foo baz,foo qux,bar baz,bar qux
  1,2,3,4
  5,6,7,8
End


def (Tb::Cmd).main_mheader(argv)
  op_mheader.parse!(argv)
  exit_if_help('mheader')
  argv = ['-'] if argv.empty?
  header = []
  if Tb::Cmd.opt_mheader_count
    c = Tb::Cmd.opt_mheader_count
    header_end_p = lambda {
      c -= 1
      c == 0 ? header.map {|a| a.compact.join(' ').strip } : nil
    }
  else
    header_end_p = lambda {
      h2 = header.map {|a| a.compact.join(' ').strip }.uniq
      header.length == h2.length ? h2 : nil
    }
  end
  creader = Tb::CatReader.open(argv, true)
  er = Tb::Enumerator.new {|y|
    creader.each {|pairs|
      if header
        ary = []
        pairs.each {|f, v| ary[f.to_i-1] = v }
        ary.each_with_index {|v,i|
          header[i] ||= []
          header[i] << v if header[i].empty? || header[i].last != v
        }
        h2 = header_end_p.call
        if h2
          pairs2 = Hash[h2.map.with_index {|v, i| ["#{i+1}", v] }]
          y.yield pairs2
          header = nil
        end
      else
        y.yield pairs
      end
    }
  }
  Tb::Cmd.opt_N = true
  output_tbenum(er)
  if header
    warn "unique header fields not recognized."
  end
end

