class CassandraMigrate

# File lib/cassandra_migrate.rb, line 194
def current_latest(options = {})
  migrations_completed(false,options).keys.max
end

# File lib/cassandra_migrate.rb, line 168
def down(date_str, options = {})
  raise "Can't reverse migration #{date_str} that didn't happen!" unless migrations_completed(false,options)[date_str]
  raise "Can't reverse migration #{date_str} that has no migration files!" unless migrations_in_dir[date_str]
  raise "Can't reverse migration #{date_str} with no down migration!" unless migrations_in_dir[date_str][:actions][:down]

  execute_migration_file migrations_in_dir[date_str][:actions][:down][:file], options
  execute_cql "DELETE FROM \"schema\".\"migrations\" WHERE date_string = '#{date_str}';", options
end

# File lib/cassandra_migrate.rb, line 187
def down_to(date_str, options = {})
  migrations_to_run = migrations_completed(false,options).keys.select { |d| d > date_str }

  STDERR.puts "Run #{migrations_to_run.size} migrations, roll back to #{date_str}."
  migrations_to_run.each { |m| down(m, options) }
end

# File lib/cassandra_migrate.rb, line 198
def latest_in_directory
  migrations_in_dir.keys.max
end

# File lib/cassandra_migrate.rb, line 216
def rollback(options = {})
  down(current_latest(options), options)
end

# File lib/cassandra_migrate.rb, line 202
def to_latest(options = {})
  latest = latest_in_directory
  raise "No latest migration!" unless latest
  up_to latest, options
end

# File lib/cassandra_migrate.rb, line 208
def to_target(date_str, options = {})
  if date_str < current_latest(options)
    down_to date_str, options
  else
    up_to date_str, options
  end
end

# File lib/cassandra_migrate.rb, line 158
def up(date_str, options = {})
  raise "Can't apply migration #{date_str} that already happened!" if migrations_completed(false,options)[date_str]
  raise "Can't apply migration #{date_str} that has no migration files!" unless migrations_in_dir[date_str]
  raise "Can't apply migration #{date_str} with no up migration!" unless migrations_in_dir[date_str][:actions][:up]

  up_filename = migrations_in_dir[date_str][:actions][:up][:file]
  execute_migration_file up_filename, options
  execute_cql "INSERT INTO \"schema\".\"migrations\" (date_string, up_filename, sha1) VALUES ('#{date_str}', '#{up_filename}', '#{sha1 up_filename}')", options
end

# File lib/cassandra_migrate.rb, line 177
def up_to(date_str, options = {})
  uncompleted_dates = migrations_in_dir.keys - migrations_completed(false,options).keys

  STDERR.puts "Uncompleted: #{uncompleted_dates.inspect}"
  migrations_to_run = uncompleted_dates.select { |d| d <= date_str }

  STDERR.puts "Run #{migrations_to_run.size} migrations, update to #{date_str}."
  migrations_to_run.each { |m| up(m, options) }
end

# File lib/cassandra_migrate.rb, line 17
def cql_client
  return @cassandra_client if @cassandra_client

  STDERR.puts "Connecting to Cassandra: #{host.inspect} / #{port.inspect}"
  @cassandra_client = Cql::Client.connect(hosts: [host].flatten, port: port, consistency: :quorum)

  @cassandra_client
end

# File lib/cassandra_migrate.rb, line 77
  def ensure_schema_keyspace_exists(options = {})
    ks = execute_cql "SELECT keyspace_name FROM system.schema_keyspaces WHERE keyspace_name = 'schema';"

    if ks.empty?
      raise "No schema keyspace in a dry run!" if options[:dry_run]

      peers = execute_cql "SELECT peer FROM system.peers;"

      @replication = [3, peers.to_a.size + 1].min
      execute_cql <<-MIGRATION, options
        CREATE KEYSPACE "schema" WITH REPLICATION =
          { 'class' : 'SimpleStrategy', 'replication_factor' : #{@replication} };
      MIGRATION
    end

    cf = execute_cql "SELECT columnfamily_name FROM system.schema_columnfamilies WHERE columnfamily_name = 'migrations' AND keyspace_name = 'schema';"
    if cf.empty?
      raise "No migration table in a dry run!" if options[:dry_run]

      execute_cql <<-MIGRATION
        CREATE TABLE "schema"."migrations" (
          "date_string" varchar,
          "up_filename" varchar,
          "sha1" varchar,
        PRIMARY KEY ("date_string", "up_filename"));
      MIGRATION
    end
  end

# File lib/cassandra_migrate.rb, line 26
def execute_cql(cql, options = {})
  if options[:dry_run]
    puts "Dry run, execute: #{cql}"
    return
  end

  last_result = nil
  # Can only execute single chunks at once
  cql.split(";").map(&:strip).select {|s| s != ""}.each do |statement|
    # Prep-then-execute so that a syntax error will be detectable as such
    last_result = cql_client.execute statement
    puts "Executing CQL: #{statement}"
  end

  last_result
end

# File lib/cassandra_migrate.rb, line 125
def execute_migration_file(path, options)
  ensure_schema_keyspace_exists(options)

  STDERR.puts "Executing migration file: #{path.inspect}"

  components = File.basename(path).split(".")
  components.shift   # Take just the extensions

  content = File.read path

  while components.size > 1
    ext = components.pop

    if ext == "erb" || ext == "erubis"
      eruby = Erubis::Eruby.new content
      content = eruby.result :replication => @replication
    else
      raise "Unknown intermediate extension in path #{path.inspect}: #{ext.inspect}!"
    end
  end

  final_type = components.first
  if ["cql", "cqlsh"].include?(final_type)
    execute_cql content, options
  elsif ["erb", "erubis"].include?(final_type)
    raise "Can't use erb as the final extension in path #{path.inspect}!"
  else
    raise "Unknown extension #{final_type.inspect} in path #{path.inspect}!"
  end
end

# File lib/cassandra_migrate.rb, line 106
def migrations_completed(refresh = false, options = {})
  return @migrations_completed if @migrations_completed && !refresh

  ensure_schema_keyspace_exists(options)

  @migrations_completed = {}

  migrations = execute_cql 'SELECT * FROM "schema"."migrations";'
  migrations.each do |migration|
    @migrations_completed[migration["date_string"]] = migration.to_hash
  end

  @migrations_completed
end

# File lib/cassandra_migrate.rb, line 43
def migrations_in_dir(refresh = false)
  return @migrations_in_dir if @migrations_in_dir && !refresh

  @migrations_in_dir = {}
  Dir[File.join migration_dir, "*"].each do |file|
    unless File.basename(file) =~ /^(\d{14})_/
      puts "No match: #{file.inspect}"
      next
    end

    unless /^(?<date_str>\d{14})_(?<desc>[^.]+)_(?<action>[^_.]+)(?<extensions>\..*)$/ =~ File.basename(file)
      puts "No match with regexp: #{file.inspect}"
      next
    end

    @migrations_in_dir[date_str] ||= {}
    migration = @migrations_in_dir[date_str]
    migration[:actions] ||= {}

    if migration[:desc] && migration[:desc] != desc
      raise "Only one migration name per date string!  #{desc.inspect} != #{migration[:desc].inspect}"
    end
    migration[:desc] = desc

    migration[:actions][action.to_sym] = {
      file: file
    }
  end

  raise "No migrations in directory #{migration_dir.inspect}!  Did you mean to specify a migration directory?" if @migrations_in_dir.empty?

  @migrations_in_dir
end

# File lib/cassandra_migrate.rb, line 121
def sha1(path)
  Digest::SHA1.hexdigest File.read path
end