FilterManager.swift

import Foundation

class FilterManager {
	class var shared: FilterManager {
		struct Static {
			static let instance: FilterManager = FilterManager()
		}

		return Static.instance
	}

	func createFilterString(formFields: [UIView], defaultCondition: String) -> String {
		var filterStrings = [String]()

		filterStrings.append(processTextFields(formFields))
		filterStrings.append(processRadioButtons(formFields))
		filterStrings.append(processInvalidDateSwitches(formFields))

		let filterString = "\(defaultCondition) \(filterStrings.reduce(String(), +))"

		return filterString
	}

	private func processTextFields(formFields: [UIView]) -> String {
		return (formFields.filter { field in
			if let textField = field as? UITextField {
				return textField.type? == "like" && !textField.text.trimWhitespace().isEmpty
			}

			return false
		} as [UITextField]).reduce(String()) { filter, textField in
			return "\(filter)and \(textField.name) like '%\(textField.text.trimWhitespace())%' "
		}
	}

	private func processRadioButtons(formFields: [UIView]) -> String {
		return (formFields.filter { field in
			if let button = field as? UIButton {
				return button.type == "radio" && button.selected
			}

			return false
		} as [UIButton]).reduce(String()) { filter, button in
			if button.value == VariableManager.Generic.AllValues {
				let allValues = (formFields.filter { field in
					if let innerButton = field as? UIButton {
						return innerButton.name == button.name && innerButton.selected == false
					}

					return false
				} as [UIButton]).reduce(String()) { values, button in
					return "\(values)\(button.name) = '\(button.value)' or "
				}

				return "\(filter)and (\(allValues.removeCharactersFromEnd(4)))"
			} else {
				return "\(filter)and \(button.name) = '\(button.value)' "
			}
		}
	}

	private func processInvalidDateSwitches(formFields: [UIView]) -> String {
		return (formFields.filter { field in
			if let switchView = field as? UISwitch {
				return switchView.type == "invalidDate" && !switchView.on
			}

			return false
		} as [UISwitch]).reduce(String()) { filter, switchView in
			return "\(filter)and (\(switchView.name) > \(DateManager.shared.isoDateFromDate(NSDate())) or \(switchView.name) = null) "
		}
	}
}