# A Cypher query for Neo4j REST API
#
# The Neo4j REST API allows querying with Cypher.
# The results are returned as a list of string headers (columns), and a data part,
# consisting of a list of all rows, every row consisting of a list of REST representations
# of the field value - Node, Relationship, Path or any simple value like String.
#
# Example:
#
#     var client = new Neo4jClient("http://neo4j:7474")
#     var query = new CypherQuery
#     query.nmatch("(n)-[r:LOVES]->(m)")
#     query.nwhere("n.name=\"Andres\"")
#     query.nreturn("m.name")
#     var res = client.cypher(query).as(JsonObject)
#     assert res["data"].as(JsonArray).first.as(JsonArray).first == "Kate"
#
# For more details, see: http://docs.neo4j.org/chunked/milestone/rest-api-cypher.html
class CypherQuery
	# Query string to perform
	private var query: String = ""

	# `params` to embed in the query like in prepared statements
	var params = new JsonObject

	# init the query from a query string
	init from_string(query: String) do
		self.query = query
	end

	# init the query with parameters
	init with_params(params: JsonObject) do
		self.params = params
	end

	# Pass the argument `value` as the parameter `key`.
	#
	# SEE: `set`
	fun []=(key: String, value: nullable Serializable) do
		params[key] = value
	end

	# Add a `CREATE` statement to the query
	fun ncreate(query: String): CypherQuery do
		self.query = "{self.query}CREATE {query} "
		return self
	end

	# Add a `START` statement to the query
	fun nstart(query: String): CypherQuery do
		self.query = "{self.query}START {query} "
		return self
	end

	# Add a `MATCH` statement to the query
	fun nmatch(query: String): CypherQuery do
		self.query = "{self.query}MATCH {query} "
		return self
	end

	# Add a `WHERE` statement to the query
	fun nwhere(query: String): CypherQuery do
		self.query = "{self.query}WHERE {query} "
		return self
	end

	# Add a `AND` statement to the query
	fun nand(query: String): CypherQuery do
		self.query = "{self.query}AND {query} "
		return self
	end

	# Add a `RETURN` statement to the query
	fun nreturn(query: String): CypherQuery do
		self.query = "{self.query}RETURN {query} "
		return self
	end

	# Pass the argument `value` as the parameter `key`.
	#
	# Return `self`.
	#
	# ```
	# var query = (new CypherQuery).
	# 		nmatch("(n)").
	# 		nwhere("n.key = \{key\}").
	#		set("key", "foo")
	#
	# assert query.params["key"] == "foo"
	# ```
	#
	# SEE: `[]=`
	fun set(key: String, value: nullable Serializable): SELF do
		self[key] = value
		return self
	end

	# Translate the query to the body of a corresponding Neo4j REST request.
	fun to_rest: JsonObject do
		var obj = new JsonObject
		obj["query"] = query
		if not params.is_empty then
			obj["params"] = params
		end
		return obj
	end

	redef fun to_s do return to_rest.to_s
end