"use strict";

const lookupTimezoneName = require("../lookup-timezone-name");

module.exports = {
	// Note that this mapping can be used to determine the losslessness of both forward and backward migrations!
	types: {
		bytes: {
			requiredAttributes: new Set([ "required" ]),
			losslessConversionTo: {}
		},
		string: {
			requiredAttributes: new Set([ "required" ]),
			losslessConversionTo: {
				bytes: (string) => Buffer.from(string, "utf8")
			}
		},
		decimal: {
			requiredAttributes: new Set([ "required", "signed", "precision" ]),
			losslessConversionTo: {
				// Decimals are already internally represented as strings
				string: (decimal) => decimal
			}
		},
		integer: {
			requiredAttributes: new Set([ "required", "signed" ]),
			losslessConversionTo: {
				string: (integer) => String(integer),
				decimal: (integer) => String(integer)
			}
		},
		boolean: {
			requiredAttributes: new Set([ "required" ]),
			losslessConversionTo: {}
		},
		date: {
			requiredAttributes: new Set([ "required", "withTimezone" ]),
			losslessConversionTo: {}
		},
		duration: {
			requiredAttributes: new Set([ "required" ]),
			losslessConversionTo: {}
		},
	},
	attributes: {
		precision: {
			validForTypes: new Set([ "decimal" ]),
			isLossless: (oldSetting, newSetting) => (newSetting > oldSetting),
			losslessTransformer: (value) => value, // No change to value
			requiresMigrationDefault: false
		},
		signed: {
			validForTypes: new Set([ "decimal", "integer" ]),
			isLossless: (oldSetting, newSetting) => (oldSetting === false && newSetting === true),
			losslessTransformer: (value, _oldAttribute, _newAttribute) => value, // No change
			requiresMigrationDefault: false,
		},
		withTimezone: {
			validForTypes: new Set([ "date" ]),
			isLossless: (oldSetting, newSetting) => (oldSetting === false && newSetting === true),
			losslessTransformer: (value) => ({
				... value,
				timezone: lookupTimezoneName("Etc/UTC")
			}),
			requiresMigrationDefault: false
		},
		required: {
			// Valid for all types
			validForTypes: true,
			isLossless: true,
			requiresMigrationDefault: true
		}
	},
	operations: {
		// 
	}
};