local json = require("util.json")

local null = json.null;

local pointer = require("util.jsonpointer")

local json_type_name = json.json_type_name

local schema_t = {}

local json_schema_object = {xml_t = {}}

local type_validators = {}

local function simple_validate(schema, data)

	if schema == "object" and type(data) == "table" then

		return type(data) == "table" and (next(data) == nil or type((next(data, nil))) == "string")

	elseif schema == "array" and type(data) == "table" then

		return type(data) == "table" and (next(data) == nil or type((next(data, nil))) == "number")

	elseif schema == "integer" then

		return math.type(data) == schema

	elseif schema == "null" then

		return data == null

	else

		return type(data) == schema

	end

end

type_validators.string = function(schema, data)

	if type(data) == "string" then

		if schema.maxLength and #data > schema.maxLength then

			return false

		end

		if schema.minLength and #data < schema.minLength then

			return false

		end

		return true

	end

	return false

end

type_validators.number = function(schema, data)

	if schema.multipleOf and data % schema.multipleOf ~= 0 then

		return false

	end

	if schema.maximum and not (data <= schema.maximum) then

		return false

	end

	if schema.exclusiveMaximum and not (data < schema.exclusiveMaximum) then

		return false

	end

	if schema.minimum and not (data >= schema.minimum) then

		return false

	end

	if schema.exclusiveMinimum and not (data > schema.exclusiveMinimum) then

		return false

	end

	return true

end

type_validators.integer = type_validators.number

local function validate(schema, data, root)

	if type(schema) == "boolean" then

		return schema

	end

	if type(schema) == "string" then

		return simple_validate(schema, data)

	end

	if type(schema) == "table" then

		if root == nil then

			root = schema

		end

		if schema["$ref"] and schema["$ref"]:sub(1, 1) == "#" then

			local referenced = pointer.resolve(root, schema["$ref"]:sub(2))

			if referenced ~= nil then

				return validate(referenced, data, root)

			end

		end

		if schema.allOf then

			for _, sub in ipairs(schema.allOf) do

				if not validate(sub, data, root) then

					return false

				end

			end

			return true

		end

		if schema.oneOf then

			local valid = 0

			for _, sub in ipairs(schema.oneOf) do

				if validate(sub, data, root) then

					valid = valid + 1

				end

			end

			return valid == 1

		end

		if schema.anyOf then

			for _, sub in ipairs(schema.anyOf) do

				if validate(sub, data, root) then

					return true

				end

			end

			return false

		end

		if schema["not"] then

			if validate(schema["not"], data, root) then

				return false

			end

		end

		if schema["if"] then

			if validate(schema["if"], data, root) then

				if schema["then"] then

					return validate(schema["then"], data, root)

				end

			else

				if schema["else"] then

					return validate(schema["else"], data, root)

				end

			end

		end

		if schema.const ~= nil and schema.const ~= data then

			return false

		end

		if schema["enum"] ~= nil then

			for _, v in ipairs(schema["enum"]) do

				if v == data then

					return true

				end

			end

			return false

		end

		if schema.type then

			if not simple_validate(schema.type, data) then

				return false

			end

			local validator = type_validators[schema.type]

			if validator then

				return validator(schema, data, root)

			end

		end

		return true

	end

end

type_validators.table = function(schema, data, root)

	if type(data) == "table" then

		if schema.maxItems and #data > schema.maxItems then

			return false

		end

		if schema.minItems and #data < schema.minItems then

			return false

		end

		if schema.required then

			for _, k in ipairs(schema.required) do

				if data[k] == nil then

					return false

				end

			end

		end

		if schema.properties then

			local additional = schema.additionalProperties or true

			for k, v in pairs(data) do

				if schema.propertyNames and not validate(schema.propertyNames, k, root) then

					return false

				end

				local s = schema.properties[k] or additional

				if not validate(s, v, root) then

					return false

				end

			end

		elseif schema.additionalProperties then

			for k, v in pairs(data) do

				if schema.propertyNames and not validate(schema.propertyNames, k, root) then

					return false

				end

				if not validate(schema.additionalProperties, v, root) then

					return false

				end

			end

		end

		if schema.uniqueItems then

			local values = {}

			for _, v in pairs(data) do

				if values[v] then

					return false

				end

				values[v] = true

			end

		end

		local p = 0

		if schema.prefixItems then

			for i, s in ipairs(schema.prefixItems) do

				if validate(s, data[i], root) then

					p = i

				else

					return false

				end

			end

		end

		if schema.items then

			for i = p + 1, #data do

				if not validate(schema.items, data[i], root) then

					return false

				end

			end

		end

		if schema.contains then

			local found = false

			for i = 1, #data do

				if validate(schema.contains, data[i], root) then

					found = true

					break

				end

			end

			if not found then

				return false

			end

		end

		return true

	end

	return false

end

type_validators.object = function(schema, data, root)

	if type(data) == "table" then

		for k in pairs(data) do

			if not (type(k) == "string") then

				return false

			end

		end

		return type_validators.table(schema, data, root)

	end

	return false

end

type_validators.array = function(schema, data, root)

	if type(data) == "table" then

		for i in pairs(data) do

			if not (type(i) == "number") then

				return false

			end

		end

		return type_validators.table(schema, data, root)

	end

	return false

end

json_schema_object.validate = validate;

return json_schema_object