#!/usr/bin/env ruby

db_url = String(ENV["DATABASE_URL"]).strip
mysql_url = String(ENV["MYSQL_DATABASE_URL"]).strip

if db_url == ""
  puts "ERROR: expected DATABASE_URL in ENV"

  exit 1
end

if db_url.start_with?("mysql")
  puts "WARNING: You are running MySQL. OpenProject has dropped support for MySQL."
  puts "         We can convert it to Postgres for you. Please setup postgres and "
  puts "         rerun this with MYSQL_DATABASE_URL pointing to your original database "
  puts "         and DATABASE_URL pointing to a new Postgres database."
  puts ""
  puts "EXAMPLE: docker run \\"
  puts "           -e MYSQL_DATABASE_URL=mysql://openproject:<PASSWORD>@localhost:3306/openproject \\"
  puts "           -e DATABASE_URL=postgresql://openproject:<PASSWORD>@localhost:5432/openproject \\"
  puts "           -it openproject/community:latest"

  exit 0 # MySQL still supported until 9.x - with 10.0 we must make this an error (exit 1)
end

if db_url.start_with?("postgresql://") && mysql_url == ""
  # nothing to do

  exit 0
end

filtered_mysql_url = mysql_url.sub(/:([^:]*)@/, ":<password>@")
filtered_db_url = db_url.sub(/:([^:]*)@/, ":<password>@")

puts "Migrating database from MySQL to PostgreSQL."
puts
puts "Import"
puts "  MySQL database"
puts "    #{filtered_mysql_url}"
puts "  into Postgres database "
puts "    #{filtered_db_url}"
puts "  ?"
puts "WARNING: This resets the given Postgres database."
puts
print "Y/n "

answer = gets.chomp

if answer.downcase == "n"
  exit 0
end

if !(db_url =~ /postgresql:\/\/(.+):(.+)@([^:]+)(?::(\d+))?\/(.+)/)
  puts "ERROR: Could not parse database URL (#{filtered_db_url})"

  exit 1
end

db_user, db_password, db_host, db_port, db_name = [$1, $2, $3, $4, $5]
db_port ||= 5432

require 'pty'

def run(cmd, silent: false, record_output: true)
  output = []

  PTY.spawn(cmd) do |stdout, stdin, pid|
    begin
      stdout.each do |line|
        output << line if record_output
        puts line unless silent
      end
    rescue Errno::EIO
      # raised when stdout is closed after process finished
    end

    Process.wait pid
  end

  [output.join("\n").strip, $?.to_i]
end

puts "Resetting target database..."
drop_cmd = "PGPASSWORD=#{db_password} psql -U #{db_user} -h #{db_host} -p #{db_port} -c 'DROP DATABASE #{db_name}'"
drop_output, _ = run drop_cmd, silent: true

if drop_output.include?("database \"#{db_name}\" does not exist") || drop_output == "DROP DATABASE"
  # that's ok then we don't have to drop it or dropped database successfully
  puts "Database dropped"
else
  puts drop_output
  exit 1 # something went wrong
end

puts "Creating database..."
create_cmd = "PGPASSWORD=#{db_password} psql -U #{db_user} -h #{db_host} -p #{db_port} -c 'CREATE DATABASE #{db_name}'"
create_output, _ = run create_cmd, silent: true

if create_output == "CREATE DATABASE"
  # created database successfully
else
  puts create_output
  exit 1 # something went wrong
end

puts "Importing database ..."

_, pgloader_status = run "pgloader --verbose #{mysql_url} #{db_url}", record_output: false

if pgloader_status != 0
  puts "\nFailed to import MySQL database into Postgres. See above."

  exit pgloader_status
end

check_fulltext_cmd = "PGPASSWORD=#{db_password} psql -U #{db_user} -h #{db_host} -p #{db_port} -c \"select 'true' from schema_migrations where version = '20180122135443'\""
check_output, check_status = run check_fulltext_cmd, silent: true

if check_status != 0
  puts check_output
  puts "Failed to check full-text status of database. See above."

  exit check_status
end

# if the version was present on MySQL already we need to redo it to
# add the postgres specific columns.
needs_fulltext_migration = check_output.include?("true")

puts "Migrating database ..."

_, migrate_status = run "bundle exec rake db:migrate", record_output: false

if migrate_status != 0
  puts "\nMigration failed. See above."

  exit migrate_status
end

if needs_fulltext_migration
  puts "Running full-text search migration"

  _, redo_status = run "bundle exec rake db:migrate:redo VERSION=20180122135443", record_output: false

  if redo_status != 0
    puts "\nFull-text search migration failed. See above."

    exit redo_status
  end

  _, extract_status = run "bundle exec rake attachments:extract_fulltext_where_missing", record_output: false

  if extract_status != 0
    puts "\nFull-text extraction failed. See above."

    exit extract_status
  end
end

puts "Re-building DAG to create Postgres-specific indices"
_, dag_status = run "bundle exec rake db:migrate:redo VERSION=20180105130053", record_output: false

if dag_status != 0
  puts "\nRebuild DAG migration failed. See above."

  exit dag_status
end

puts "Migration from MySQL to Postgres completed successfully!"