# * George Moschovitis  <gm@navel.gr>
# (c) 2004-2005 Navel, all rights reserved.
# $Id: mysql.rb 17 2005-04-14 16:03:40Z gmosx $

begin
	require 'mysql'
rescue Object => ex
	Logger.error 'Ruby-Mysql bindings are not installed!'
	Logger.error ex
end

require 'og/adapters/base'

module Og

# The MySQL adapter. This adapter communicates with 
# an MySQL rdbms. For extra documentation see 
# lib/og/adapter.rb

class MysqlAdapter < Adapter

	def initialize
		super
		@typemap.update(TrueClass => 'tinyint')
		@typecast.update(TrueClass => "#\{:s: ? \"1\" : 'NULL' \}")
	end
	
	def self.escape(str)
		return nil unless str
		return Mysql.quote(str)
	end

	def self.timestamp(time = Time.now)
		return nil unless time
		return time.strftime("%Y%m%d%H%M%S")
	end
	
	def self.date(date)
		return nil unless date
		return "#{date.year}-#{date.month}-#{date.mday}" 
	end
	
	def write_prop(p)
		if p.klass.ancestors.include?(Integer)
			return "#\{@#{p.symbol} || 'NULL'\}"
		elsif p.klass.ancestors.include?(Float)
			return "#\{@#{p.symbol} || 'NULL'\}"		
		elsif p.klass.ancestors.include?(String)
			return %|#\{@#{p.symbol} ? "'#\{#{self.class}.escape(@#{p.symbol})\}'" : 'NULL'\}|
		elsif p.klass.ancestors.include?(Time)
			return %|#\{@#{p.symbol} ? "'#\{#{self.class}.timestamp(@#{p.symbol})\}'" : 'NULL'\}|
		elsif p.klass.ancestors.include?(Date)
			return %|#\{@#{p.symbol} ? "'#\{#{self.class}.date(@#{p.symbol})\}'" : 'NULL'\}|
		elsif p.klass.ancestors.include?(TrueClass)
			return "#\{@#{p.symbol} ? 1 : 0 \}"
		else 
			# gmosx: keep the '' for nil symbols.
			return %|#\{@#{p.symbol} ? "'#\{#{self.class}.escape(@#{p.symbol}.to_yaml)\}'" : "''"\}|
		end
	end		

	def read_prop(p, idx)
		if p.klass.ancestors.include?(Integer)
			return "res[#{idx}].to_i"
		elsif p.klass.ancestors.include?(Float)
			return "res[#{idx}].to_f"
		elsif p.klass.ancestors.include?(String)
			return "res[#{idx}]"
		elsif p.klass.ancestors.include?(Time)
			return "#{self.class}.parse_timestamp(res[#{idx}])"
		elsif p.klass.ancestors.include?(Date)
			return "#{self.class}.parse_date(res[#{idx}])"
		elsif p.klass.ancestors.include?(TrueClass)
			return "('0' != res[#{idx}])"
		else 
			return "YAML::load(res[#{idx}])"
		end				
	end

	def create_db(database, user = nil, password = nil)
		# gmosx: system is used to avoid shell expansion.
		system 'mysqladmin', '-f', "--user=#{user}", "--password=#{password}", 'create', database
		super
	end

	def drop_db(database, user = nil, password = nil)
		system 'mysqladmin', '-f', "--user=#{user}", "--password=#{password}", 'drop', database
		super
	end

	def props_for_insert(klass)
		klass.__props.reject { |p| :oid == p.symbol }
	end

	def insert_code(klass, db)
		props = props_for_insert(klass)
		values = props.collect { |p| write_prop(p) }.join(',') 
		
		sql = "INSERT INTO #{klass::DBTABLE} (#{props.collect {|p| p.name}.join(',')}) VALUES (#{values})"

		%{
			conn.store.query_with_result = false
			conn.store.query "#{sql}"
			@oid = conn.store.insert_id()
		}
	end

	def new_connection(db)
		return MysqlConnection.new(db)
	end

	def calc_field_index(klass, db)
		res = db.query "SELECT * FROM #{klass::DBTABLE} LIMIT 1"
		meta = db.managed_classes[klass]
	
		for idx in (0...res.num_fields)
			meta.field_index[res.fetch_field.name] = idx
		end

	ensure
		res.free if res
	end

	def create_fields(klass)
		fields = []
		
		klass.__props.each do |p|
			klass.sql_index(p.symbol) if p.meta[:sql_index]
				
			field = "#{p.symbol}"
			
			if p.meta and p.meta[:sql]
				field << " #{p.meta[:sql]}"
			else
				field << " #{@typemap[p.klass]}"
				
				if p.meta
					# set default value (gmosx: not that useful in the
					# current implementation).
					if default = p.meta[:default]
						field << " DEFAULT #{default.inspect} NOT NULL"
					end
				
					# set unique
					# FIXME: correctly handle UNIQUE constrain.
					# field << " UNIQUE" if p.meta[:unique]

					# attach extra sql
					if extra_sql = p.meta[:extra_sql]
						field << " #{extra_sql}"
					end
				end
			end
			
			fields << field 
		end

		return fields
	end

	def create_table(klass, db)
		conn = db.get_connection

		fields = create_fields(klass)

		sql = "CREATE TABLE #{klass::DBTABLE} (#{fields.join(', ')}"
		
		conn.store.query_with_result = true 

		# Create table constrains
		
		if klass.__meta and constrains = klass.__meta[:sql_constrain]
			sql << ", #{constrains.join(', ')}"
		end
		
		sql << ');'
		
		begin
			conn.store.query(sql)
			Logger.info "Created table '#{klass::DBTABLE}'."
		rescue => ex
			if ex.errno == 1050 # table already exists.
				Logger.debug "Table already exists" if $DBG
				return 
			else
				raise
			end
		end
		
		# Create indices
		
		if klass.__meta and indices = klass.__meta[:sql_index] 
			for data in indices
				idx, options = *data
				idx = idx.to_s
				pre_sql, post_sql = options[:pre], options[:post]
				idxname = idx.gsub(/ /, "").gsub(/,/, "_").gsub(/\(.*\)/, "")
				conn.store.query("CREATE #{pre_sql} INDEX #{klass::DBTABLE}_#{idxname}_idx #{post_sql} ON #{klass::DBTABLE} (#{idx})")
			end
		end

		# Create join tables if needed. Join tables are used in
		# 'many_to_many' relations.
		
		if klass.__meta and joins = klass.__meta[:sql_join] 
			for data in joins
				# the class to join to and some options.
				join_name, join_class, options = *data
				
				# gmosx: dont use DBTABLE here, perhaps the join class
				# is not managed yet.
				join_table = "#{self.class.join_table(klass, join_class, join_name)}"
				join_src = "#{self.class.encode(klass)}_oid"
				join_dst = "#{self.class.encode(join_class)}_oid"
				begin
					conn.store.query("CREATE TABLE #{join_table} ( key1 integer NOT NULL, key2 integer NOT NULL )")
					conn.store.query("CREATE INDEX #{join_table}_key1_idx ON #{join_table} (key1)")
					conn.store.query("CREATE INDEX #{join_table}_key2_idx ON #{join_table} (key2)")
				rescue => ex
					if ex.errno == 1050 # table already exists.
						Logger.debug "Join table already exists" if $DBG
					else
						raise
					end
				end
			end
		end		
		
	ensure
		db.put_connection
	end

	def eval_og_oid(klass)
		klass.class_eval %{
			prop_accessor :oid, Fixnum, :sql => 'integer AUTO_INCREMENT PRIMARY KEY'
		}
	end
end

# The MySQL connection.

class MysqlConnection < Connection

	def initialize(db)
		super

		config = db.config

		@store = Mysql.connect(
			config[:address] || 'localhost', 
			config[:user],
			config[:password], 
			config[:database]
		)
	rescue => ex
		if ex.errno == 1049 # database does not exist.
			Logger.info "Database '#{config[:database]}' not found!"
			@db.adapter.create_db(config[:database], config[:user], config[:password])
			retry
		end
		raise
	end

	def close
		@store.close
		super
	end

	def prepare(sql)
		raise 'Not implemented!'
	end

	def query(sql)
		Logger.debug sql if $DBG
		begin
			@store.query_with_result = true 
			return @store.query(sql)
		rescue => ex
			handle_db_exception(ex, sql)
		end
	end

	def exec(sql)
		Logger.debug sql if $DBG
		begin
			@store.query_with_result = false
			@store.query(sql) 
		rescue => ex
			handle_db_exception(ex, sql)
		end
	end

	def start
		#	@store.transaction
	end
	
	def commit
		# @store.commit
	end

	def rollback
		# @store.rollback
	end

	def valid_res?(res)
		return !(res.nil? or 0 == res.num_rows)
	end

	def read_one(res, klass)
		return nil unless valid_res?(res)
		
		row = res.fetch_row
		obj = klass.allocate
		obj.og_read(row)
		
		res.free
		return obj
	end

	def read_all(res, klass)
		return [] unless valid_res?(res)

		objects = []

		for tuple in (0...res.num_rows)
			row = res.fetch_row

			obj = klass.allocate
			obj.og_read(row)
			
			objects << obj
		end
	
		res.free
		return objects 
	end

	def read_int(res, idx = 0)
		val =  res.fetch_row[idx].to_i
		res.free
		return val
	end

	def get_row(res)
		res.fetch_row
	end

end

end