document.addEventListener('DOMContentLoaded', () => {
    Tone.start();

    const synth = new Tone.Synth().toDestination();

    const a440Input = document.getElementById('a440');
    const transposeInput = document.getElementById('transpose');
    const instrumentSelect = document.getElementById('instrument');
    const instlabel = document.getElementById('instrument-label');
    const tuningSelect = document.getElementById('tuning');
    const tuningModeSelect = document.getElementById('tuning-mode');
    const stringsDiv = document.getElementById('strings');
    const playAllButton = document.getElementById('play-all');
    const outputDiv = document.getElementById('output');

    const instrumentTunings = {
        "ukulele": {
            "standard": [67 + 12, 60 + 12, 64 + 12, 69 + 12],
            "low-g": [55 + 12, 60 + 12, 64 + 12, 69 + 12],
            "harmonic-minor": [67 + 12, 58 + 12, 62 + 12, 67 + 12],
            "suspended-fourth": [67 + 12, 60 + 12, 53 + 12, 60 + 12],
            "lydian": [67 + 12, 60 + 12, 64 + 12, 66 + 12],
            "diminished": [67 + 12, 59 + 12, 62 + 12, 65 + 12],
            "augmented": [67 + 12, 61 + 12, 64 + 12, 68 + 12],
            "open-fifths": [67 + 12, 62 + 12, 69 + 12, 62 + 12],
            "double-unison": [67 + 12, 67 + 12, 60 + 12, 60 + 12],
            "ionian": [67 + 12, 60 + 12, 64 + 12, 69 + 12],
            "dorian": [67 + 12, 58 + 12, 62 + 12, 69 + 12],
            "mixo-dorian": [65 + 12, 58 + 12, 67 + 12, 69 + 12],
            "phrygian": [67 + 12, 56 + 12, 62 + 12, 69 + 12],
            "mixolydian": [67 + 12, 60 + 12, 62 + 12, 69 + 12],
            "aeolian": [67 + 12, 58 + 12, 62 + 12, 67 + 12],
            "locrian": [67 + 12, 56 + 12, 60 + 12, 67 + 12]
        },
        "guitar": {
            "standard": [40, 45, 50, 55, 59, 64],
            "drop-d": [38, 45, 50, 55, 59, 64],
            "dadgad": [38, 45, 50, 55, 57, 64],
            "open-g": [38, 43, 47, 50, 55, 59],
            "open-d": [38, 43, 50, 54, 57, 64],
            "open-c": [36, 40, 43, 48, 52, 57],
            "half-step-down": [39, 43, 48, 52, 55, 60],
            "full-step-down": [38, 43, 48, 53, 57, 62],
            "double-drop-d": [38, 43, 48, 50, 55, 59],
            "new-standard": [36, 40, 45, 50, 54, 59],
            "nashville-high-strung": [40, 45, 50, 55, 59, 64],
            "orkney": [36, 40, 43, 36, 40, 43],
            "modal-tuning-1": [40, 45, 39, 50, 45, 64],
            "modal-tuning-2": [40, 45, 37, 50, 45, 64],
            "db-custom": [49, 54, 59, 56, 71, 63]
        }
    };
    let currentTuning = [];
    let currentA440 = 440;
    let currentTranspose = 0;
    let tuningMode = "equal";

    const harmonicFrequencyRatios = {
        "C": 1.0, "Db": 17/16, "D": 9/8, "Eb": 19/16, "E": 5/4,
        "F": 21/16, "Gb": 11/8, "G": 3/2, "Ab": 13/8, "A": 5/3,
        "Bb": 7/4, "B": 15/8, "C_octave": 2.0
    };

    function updateInstrument() {
        const selectedInstrument = instrumentSelect.value;
        tuningSelect.innerHTML = "";
        let inst = instrumentSelect.value;
        instlabel.innerText = inst.charAt(0).toUpperCase() + inst.slice(1) + " Tuner";
        Object.keys(instrumentTunings[selectedInstrument]).forEach(tuning => {
            let option = document.createElement("option");
            option.value = tuning;
            option.textContent = tuning.replace(/-/g, " ").toUpperCase();
            tuningSelect.appendChild(option);
        });
        updateTuning();
    }

    function updateTuning() {
        const selectedInstrument = instrumentSelect.value;
        const selectedTuning = tuningSelect.value;
        currentTuning = instrumentTunings[selectedInstrument][selectedTuning];
        updateStringButtons();
    }

    function updateStringButtons() {
        stringsDiv.innerHTML = "";
        currentTuning.forEach((midiNote, index) => {
            let button = document.createElement("button");
            button.classList.add("string-button");
            button.textContent = `String ${index + 1}`;
            button.addEventListener("click", () => playNote(midiNote));
            stringsDiv.appendChild(button);
        });
    }

    function calculateFrequency(midiNote, tuningMode) {
        const referenceNote = 60;
        const referenceFreq = currentA440 * Math.pow(2, (referenceNote - 69) / 12);

        if (tuningMode === "harmonic") {
            const noteNames = ["C", "Db", "D", "Eb", "E", "F", "Gb", "G", "Ab", "A", "Bb", "B"];
            const octave = Math.floor(midiNote / 12) - 5;
            const note = noteNames[midiNote % 12];
            return referenceFreq * harmonicFrequencyRatios[note] * Math.pow(2, octave);
        } else {
            return 440 * Math.pow(2, (midiNote - 69) / 12);
        }
    }

    function playNote(midiNote) {
        const a440Value = parseFloat(a440Input.value);
        const transposeValue = parseInt(transposeInput.value);

        if (!isNaN(a440Value)) currentA440 = a440Value;
        if (!isNaN(transposeValue)) currentTranspose = transposeValue;

        const adjustedMidiNote = midiNote + currentTranspose;
        const frequency = calculateFrequency(adjustedMidiNote, tuningMode);

        const referenceFrequencyRatio = currentA440 / 440;
        const adjustedFrequency = frequency * referenceFrequencyRatio;

        synth.set({ oscillator: { type: 'sine' } });
        synth.triggerAttackRelease(adjustedFrequency, "1.75s");

        outputDiv.textContent = `Playing: ${Tone.Frequency(adjustedFrequency).toNote()} (Freq: ${adjustedFrequency.toFixed(2)} Hz, A4 Ref: ${currentA440} Hz, Transpose: ${currentTranspose} semitones)`;
    }

    playAllButton.addEventListener('click', () => {
        let delay = 0;
        Tone.Transport.stop();
        Tone.Transport.cancel();
        currentTuning.forEach((midiNote) => {
            Tone.Transport.scheduleOnce(() => {
                playNote(midiNote);
            }, `+${delay}`);
            delay += 0.2;
        });
        Tone.Transport.start();
    });

    instrumentSelect.addEventListener('change', updateInstrument);
    tuningSelect.addEventListener('change', updateTuning);
    tuningModeSelect.addEventListener('change', () => {
        tuningMode = tuningModeSelect.value;
    });
    updateInstrument();

    a440Input.addEventListener('change', () => {
        outputDiv.textContent = `A4 Reference set to ${a440Input.value} Hz`;
    });

    transposeInput.addEventListener('change', () => {
        outputDiv.textContent = `Transpose set to ${transposeInput.value} semitones`;
    });
});