PostgreSQLData+Point.swift

import Foundation

/// A 2-dimenstional (double[2]) point.
public struct PostgreSQLPoint: Codable, Equatable {
    /// The point's x coordinate.
    public var x: Double

    /// The point's y coordinate.
    public var y: Double

    /// Create a new `Point`
    public init(x: Double, y: Double) {
        self.x = x
        self.y = y
    }
}

extension PostgreSQLPoint: CustomStringConvertible {
    /// See `CustomStringConvertible`.
    public var description: String {
        return "(\(x),\(y))"
    }
}

extension PostgreSQLPoint: PostgreSQLDataConvertible {
    /// See `PostgreSQLDataConvertible`.
    public static func convertFromPostgreSQLData(_ data: PostgreSQLData) throws -> PostgreSQLPoint {
        guard case .point = data.type else {
            throw PostgreSQLError.decode(self, from: data)
        }
        switch data.storage {
        case .text(let string):
            let parts = string.split(separator: ",")
            var x = parts[0]
            var y = parts[1]
            let leftParen = x.popFirst()
            assert(leftParen == "(")
            let rightParen = y.popLast()
            assert(rightParen == ")")
            return .init(x: Double(x)!, y: Double(y)!)
        case .binary(let value):
            let x = value[0..<8]
            let y = value[8..<16]
            return .init(x: x.as(Double.self, default: 0), y: y.as(Double.self, default: 0))
        case .null: throw PostgreSQLError.decode(self, from: data)
        }
    }

    /// See `PostgreSQLDataConvertible`.
    public func convertToPostgreSQLData() throws -> PostgreSQLData {
        return PostgreSQLData(.point, binary: Data.of(x) + Data.of(y))
    }
}