require 'active_record/connection_adapters/sqlite_adapter'

gem 'sqlite3', '~> 1.3.5'
require 'sqlite3'

module ActiveRecord
  module ConnectionHandling
    # sqlite3 adapter reuses sqlite_connection.
    def sqlite3_connection(config) # :nodoc:
      # Require database.
      unless config[:database]
        raise ArgumentError, "No database file specified. Missing argument: database"
      end

      # Allow database path relative to Rails.root, but only if
      # the database path is not the special path that tells
      # Sqlite to build a database only in memory.
      if defined?(Rails.root) && ':memory:' != config[:database]
        config[:database] = File.expand_path(config[:database], Rails.root)
      end

      unless 'sqlite3' == config[:adapter]
        raise ArgumentError, 'adapter name should be "sqlite3"'
      end

      db = SQLite3::Database.new(
        config[:database],
        :results_as_hash => true
      )

      db.busy_timeout(config[:timeout]) if config[:timeout]

      ConnectionAdapters::SQLite3Adapter.new(db, logger, config)
    end
  end

  module ConnectionAdapters #:nodoc:
    class SQLite3Adapter < SQLiteAdapter # :nodoc:
      def quote(value, column = nil)
        if value.kind_of?(String) && column && column.type == :binary && column.class.respond_to?(:string_to_binary)
          s = column.class.string_to_binary(value).unpack("H*")[0]
          "x'#{s}'"
        else
          super
        end
      end

      # Returns the current database encoding format as a string, eg: 'UTF-8'
      def encoding
        @connection.encoding.to_s
      end

      # Returns true.
      def supports_explain?
        true
      end

      # DATABASE STATEMENTS ======================================

      def explain(arel, binds = [])
        sql = "EXPLAIN QUERY PLAN #{to_sql(arel, binds)}"
        ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
      end

      class ExplainPrettyPrinter
        # Pretty prints the result of a EXPLAIN QUERY PLAN in a way that resembles
        # the output of the SQLite shell:
        #
        #   0|0|0|SEARCH TABLE users USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)
        #   0|1|1|SCAN TABLE posts (~100000 rows)
        #
        def pp(result) # :nodoc:
          result.rows.map do |row|
            row.join('|')
          end.join("\n") + "\n"
        end
      end
    end
  end
end