#!/usr/bin/env ruby
# encoding: UTF-8
require 'soywiki'

oldname, newname = *ARGV

MEMO = ["Updating inbound and outbound links..."]

def report(file, oldname, newname)
  MEMO <<  "  - In #{file}: #{oldname.to_page_title} -> #{newname.to_page_title}"
end

def change_all_absolute_links(oldname, newname)
  MEMO << "- Updating all absolute links"
  target_files = `grep -rlF '#{oldname.to_page_title}' *`.strip.split(/\n/)
  target_files.select {|f| f !~ /(\.swp|\.swo)$/}.each do |file|
    text = File.read(file)
    begin
      regex = /\b#{oldname.to_page_title}\b/
      matches = text.scan(regex)
      text = text.gsub(regex, newname.to_page_title)
      File.open(file, 'w') {|f| f.puts text}
      report file, oldname.to_page_title, newname.to_page_title
    rescue
      puts "Error processing #{file}: #$!"
    end
  end
end

def change_unqualified_inbound_links_in_same_namespace(oldname, newname)
  MEMO << "- Updating unqualified inbound links"
  target_files = `grep -rlF '#{oldname.short_page_title}' #{oldname.namespace}/*`.strip.split(/\n/)
  target_files.select {|f| f !~ /(\.swp|\.swo)$/}.each do |file|
    text = File.read(file)
    begin
      text = text.gsub(/(\A|\s)#{oldname.short_page_title}\b/, newname.to_page_title)
      File.open(file, 'w') {|f| f.puts text}
      report file, oldname.short_page_title, newname
    rescue
      puts "Error processing #{file}: #$!"
    end
  end
end

RELATIVE_LINK_REGEX = /(\A|\s)([A-Z][a-z]+[A-Z]\w*)/

def absolutize_unqualified_outbound_links(oldname, newname)
  MEMO << "Absolutizing unqualified inbound links"
  target_file = newname.to_file_path
  if File.exist?(target_file)
    text = File.read(target_file)
    begin
      matches = text.scan(RELATIVE_LINK_REGEX).map {|x| x[1]}.
        select {|match| match.strip != "" }.
        select {|match| File.exist?( oldname.namespace + "/#{match}" ) }
      puts MEMO << "  - In file #{target_file}: matches: #{matches.inspect}"

      text = text.gsub(RELATIVE_LINK_REGEX) do |match|
        if matches.include?($2)
          res = "#$1#{oldname.namespace}.#{$2}"
          MEMO <<  "  - In file #{target_file}: #{$2} -> #{res.strip}"
          res
        else
          MEMO <<  "  - In file #{target_file}: skipping #{$2}"
          match
        end
      end
      File.open(target_file, 'w') {|f| f.puts text}
    rescue
      puts "Error processing #{target_file}: #$!"
    end
  end
end


# Three other cases to cover, involving namespaces:
#
# Case 1: newname is in same namespace as oldname
#
# In the directory for OldName's namespace, change all unqualified referenecs to
# OldName to NewName

if oldname.namespace == newname.namespace
  MEMO << "- Updating unqualified links in same namespace"
  target_files = `grep -rlF '#{oldname.short_page_title}' #{oldname.namespace}/*`.strip.split(/\n/)
  target_files.select {|f| f !~ /(\.swp|\.swo)$/}.each do |file|
    text = File.read(file)
    begin
      text = text.gsub(/(\A|\s)(#{oldname.short_page_title})\b/, newname.short_page_title)
      File.open(file, 'w') {|f| f.puts text}
      report file, oldname.short_page_title, newname.short_page_title
    rescue
      puts "Error processing #{file}: #$!"
    end
  end
end

# Case 2: newname is in different namespace from oldname
if oldname.namespace != newname.namespace
  # In the directory for OldName's namespace, change all unqualified references to
  # OldName to newnamespace.NewName (i.e. NewName).
  change_unqualified_inbound_links_in_same_namespace(oldname, newname)
  # And in the renamed file, change all unqualified references to
  # PageName to oldnamespace.PageName
  absolutize_unqualified_outbound_links(oldname, newname)
end

# Finally,
change_all_absolute_links oldname, newname

puts MEMO.join("\n")