classdef DP_Fiber_test < IMDDTestCase
    methods (Test, TestTags = {'unit', 'fast', 'optical', 'dp_fiber'})
        function constructorStoresConfigurationAndStartsWithEmptyState(testCase)
            fiber = makeIdentityFiber();

            testCase.verifyEqual(fiber.L, 0);
            testCase.verifyEqual(fiber.dz, 1);
            testCase.verifyEqual(fiber.lambda, 1550);
            testCase.verifyEqual(fiber.rng, 7);
            testCase.verifyEqual(fiber.gamma, 0);
            testCase.verifyEqual(fiber.fa, 64e9);
            testCase.verifyEqual(fiber.X_alpha, 0);
            testCase.verifyEqual(fiber.D, 0);
            testCase.verifyEqual(fiber.Ds, 0);
            testCase.verifyEqual(fiber.Dpmd, 0);
            testCase.verifyEqual(fiber.n_waveplates, 1);
            testCase.verifyEqual(fiber.useGPU, false);
            testCase.verifyEqual(fiber.useSingle, false);
            testCase.verifyTrue(isstruct(fiber.state));
            testCase.verifyEmpty(fieldnames(fiber.state));
        end

        function processPreservesAZeroImpairmentDualPolarizationSignal(testCase)
            fiber = makeIdentityFiber();
            inputMatrix = [ ...
                1 + 1i,   2 - 1i; ...
                0.5,      -0.25i; ...
               -1 + 0.2i,  0.75 - 0.5i; ...
                0,         0.25 + 0.75i];

            sigIn = Signal(inputMatrix, "fs", fiber.fa);
            sigOut = fiber.process(sigIn);

            testCase.verifyClass(sigOut, "Signal");
            testCase.verifyEqual(sigOut.fs, sigIn.fs);
            testCase.verifyEqual(size(sigOut.signal), size(sigIn.signal));
            testCase.verifyEqual(sigOut.signal, sigIn.signal, "AbsTol", 1e-12);
            testCase.verifyEqual(height(sigOut.logbook), 1);
        end

        function process_ProducesIdentityOutputForRawMatrixInput(testCase)
            fiber = makeIdentityFiber();
            inputMatrix = [ ...
                1 + 1i,   2 - 1i; ...
                0.5,      -0.25i; ...
               -1 + 0.2i,  0.75 - 0.5i; ...
                0,         0.25 + 0.75i];

            sigOut = fiber.process_(inputMatrix, fiber.fa);

            testCase.verifyEqual(size(sigOut), size(inputMatrix));
            testCase.verifyEqual(sigOut, inputMatrix, "AbsTol", 1e-12);
        end
    end
end

function fiber = makeIdentityFiber()
    fiber = DP_Fiber( ...
        "L", 0, ...
        "dz", 1, ...
        "lambda", 1550, ...
        "rng", 7, ...
        "gamma", 0, ...
        "fa", 64e9, ...
        "X_alpha", 0, ...
        "D", 0, ...
        "Ds", 0, ...
        "Dpmd", 0, ...
        "beat_len", 1e9, ...
        "corr_len", 1e9, ...
        "manakov", 0, ...
        "SS_dphimax", 5e-3, ...
        "SS_dzmax", 1, ...
        "SS_dzmin", 1, ...
        "n_waveplates", 1, ...
        "useGPU", false, ...
        "useSingle", false);
end