// Level system — puzzle definitions, verification, and progression
import { state } from './state.js';
import { evaluate } from './gates.js';

// Level definitions
export const LEVELS = [
    {
        id: 'buffer',
        category: 'Logic Basics',
        title: 'Buffer',
        description: 'Connect input to output directly. Pass the value through.',
        availableGates: ['INPUT', 'OUTPUT'],
        testCases: [
            { inputs: { 0: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 1 }, outputs: { 0: 1 } }
        ],
        hints: ['Use only one INPUT and one OUTPUT gate.'],
        difficulty: 1
    },
    {
        id: 'not_gate',
        category: 'Logic Basics',
        title: 'NOT Gate',
        description: 'Build a NOT gate using only NAND gates. Invert the input signal.',
        availableGates: ['INPUT', 'OUTPUT', 'NAND'],
        testCases: [
            { inputs: { 0: 0 }, outputs: { 0: 1 } },
            { inputs: { 0: 1 }, outputs: { 0: 0 } }
        ],
        hints: ['Connect both inputs of a NAND gate to the same signal.'],
        difficulty: 1
    },
    {
        id: 'and_gate',
        category: 'Logic Basics',
        title: 'AND Gate',
        description: 'Build an AND gate using only NAND gates. AND = NAND with inverted output.',
        availableGates: ['INPUT', 'OUTPUT', 'NAND'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 1 } }
        ],
        hints: ['NOT(NAND) = AND. You need 2 NAND gates.', 'Use a NAND gate as a NOT on the output.'],
        difficulty: 2
    },
    {
        id: 'or_gate',
        category: 'Logic Basics',
        title: 'OR Gate',
        description: 'Build an OR gate using NAND gates. OR = NAND(NOT A, NOT B).',
        availableGates: ['INPUT', 'OUTPUT', 'NAND'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 1 } },
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 1 } },
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 1 } }
        ],
        hints: ['Invert both inputs first, then NAND them.', 'You need 3 NAND gates total.'],
        difficulty: 2
    },
    {
        id: 'xor_gate',
        category: 'Logic Basics',
        title: 'XOR Gate',
        description: 'Build an XOR gate using NAND gates. True when inputs differ.',
        availableGates: ['INPUT', 'OUTPUT', 'NAND'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 1 } },
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 1 } },
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 0 } }
        ],
        hints: ['XOR = (A NAND B) NAND (NOT(A NAND NOT B) NAND NOT(NOT A NAND B))', 'This requires 4-5 NAND gates.'],
        difficulty: 3
    },
    {
        id: 'xnor_gate',
        category: 'Logic Basics',
        title: 'XNOR Gate',
        description: 'Build an XNOR gate. True when both inputs are equal.',
        availableGates: ['INPUT', 'OUTPUT', 'NAND'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 1 } },
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 1 } }
        ],
        hints: ['XNOR is the inverse of XOR.', 'Build XOR first, then invert the output with another NAND-as-NOT.'],
        difficulty: 3
    },
    // ============ Combinational Logic ============
    {
        id: 'mux_2to1',
        category: 'Combinational Logic',
        title: '2:1 Multiplexer',
        description: 'Build a MUX. When SEL=0, output A. When SEL=1, output B. Three inputs: A (0), B (1), SEL (2).',
        availableGates: ['INPUT', 'OUTPUT', 'AND', 'OR', 'NOT'],
        testCases: [
            { inputs: { 0: 0, 1: 0, 2: 0 }, outputs: { 0: 0 } },  // SEL=0 → A=0
            { inputs: { 0: 1, 1: 0, 2: 0 }, outputs: { 0: 1 } },  // SEL=0 → A=1
            { inputs: { 0: 0, 1: 1, 2: 0 }, outputs: { 0: 0 } },  // SEL=0 → A=0
            { inputs: { 0: 1, 1: 1, 2: 0 }, outputs: { 0: 1 } },  // SEL=0 → A=1
            { inputs: { 0: 0, 1: 0, 2: 1 }, outputs: { 0: 0 } },  // SEL=1 → B=0
            { inputs: { 0: 0, 1: 1, 2: 1 }, outputs: { 0: 1 } },  // SEL=1 → B=1
            { inputs: { 0: 1, 1: 0, 2: 1 }, outputs: { 0: 0 } },  // SEL=1 → B=0
            { inputs: { 0: 1, 1: 1, 2: 1 }, outputs: { 0: 1 } }   // SEL=1 → B=1
        ],
        hints: ['MUX = (A AND NOT SEL) OR (B AND SEL).', 'You need 1 NOT, 2 AND, and 1 OR gate.'],
        difficulty: 2
    },
    {
        id: 'demux_1to2',
        category: 'Combinational Logic',
        title: '1:2 Demultiplexer',
        description: 'Route input to one of two outputs based on SEL. Inputs: DATA (0), SEL (1). Outputs: Q0, Q1.',
        availableGates: ['INPUT', 'OUTPUT', 'AND', 'NOT'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 0, 1: 0 } },  // DATA=0, SEL=0 → Q0=0, Q1=0
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 1, 1: 0 } },  // DATA=1, SEL=0 → Q0=1, Q1=0
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 0, 1: 0 } },  // DATA=0, SEL=1 → Q0=0, Q1=0
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 0, 1: 1 } }   // DATA=1, SEL=1 → Q0=0, Q1=1
        ],
        hints: ['Q0 = DATA AND NOT SEL. Q1 = DATA AND SEL.', 'You need 1 NOT and 2 AND gates.'],
        difficulty: 2
    },
    {
        id: 'and3',
        category: 'Combinational Logic',
        title: '3-input AND',
        description: 'Build a 3-input AND gate. Output is 1 only when all three inputs are 1.',
        availableGates: ['INPUT', 'OUTPUT', 'AND'],
        testCases: [
            { inputs: { 0: 0, 1: 0, 2: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 0, 2: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 1, 2: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 0, 1: 1, 2: 1 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 1, 2: 1 }, outputs: { 0: 1 } }
        ],
        hints: ['Chain two AND gates: (A AND B) AND C.'],
        difficulty: 1
    },
    {
        id: 'majority',
        category: 'Combinational Logic',
        title: 'Majority Gate',
        description: 'Output 1 if at least two of the three inputs are 1.',
        availableGates: ['INPUT', 'OUTPUT', 'AND', 'OR'],
        testCases: [
            { inputs: { 0: 0, 1: 0, 2: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 0, 2: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 0, 1: 1, 2: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 0, 1: 0, 2: 1 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 1, 2: 0 }, outputs: { 0: 1 } },
            { inputs: { 0: 1, 1: 0, 2: 1 }, outputs: { 0: 1 } },
            { inputs: { 0: 0, 1: 1, 2: 1 }, outputs: { 0: 1 } },
            { inputs: { 0: 1, 1: 1, 2: 1 }, outputs: { 0: 1 } }
        ],
        hints: ['Majority = (A AND B) OR (A AND C) OR (B AND C).', 'You need 3 AND gates and 2 OR gates.'],
        difficulty: 2
    },
    {
        id: 'parity',
        category: 'Combinational Logic',
        title: 'Even Parity',
        description: 'Output 1 if an even number of inputs are 1 (0 counts as even). Three inputs.',
        availableGates: ['INPUT', 'OUTPUT', 'XOR', 'NOT'],
        testCases: [
            { inputs: { 0: 0, 1: 0, 2: 0 }, outputs: { 0: 1 } },  // 0 ones = even
            { inputs: { 0: 1, 1: 0, 2: 0 }, outputs: { 0: 0 } },  // 1 one = odd
            { inputs: { 0: 0, 1: 1, 2: 0 }, outputs: { 0: 0 } },
            { inputs: { 0: 0, 1: 0, 2: 1 }, outputs: { 0: 0 } },
            { inputs: { 0: 1, 1: 1, 2: 0 }, outputs: { 0: 1 } },  // 2 ones = even
            { inputs: { 0: 1, 1: 0, 2: 1 }, outputs: { 0: 1 } },
            { inputs: { 0: 0, 1: 1, 2: 1 }, outputs: { 0: 1 } },
            { inputs: { 0: 1, 1: 1, 2: 1 }, outputs: { 0: 0 } }   // 3 ones = odd
        ],
        hints: ['XOR gives odd parity. Invert it for even parity.', 'Chain: NOT(A XOR B XOR C).'],
        difficulty: 2
    },
    // ============ Arithmetic ============
    {
        id: 'half_adder',
        category: 'Arithmetic',
        title: 'Half Adder',
        description: 'Build a half adder. Two outputs: Sum (A XOR B) and Carry (A AND B).',
        availableGates: ['INPUT', 'OUTPUT', 'NAND'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 0, 1: 0 } },
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 1, 1: 0 } },
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 1, 1: 0 } },
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 0, 1: 1 } }
        ],
        hints: ['Two independent functions: Sum=XOR, Carry=AND.', 'You need 2 OUTPUT gates.'],
        difficulty: 3
    },
    {
        id: 'full_adder',
        category: 'Arithmetic',
        title: 'Full Adder',
        description: 'Build a full adder with carry-in. Outputs: Sum and Carry-out.',
        availableGates: ['INPUT', 'OUTPUT', 'NAND'],
        testCases: [
            { inputs: { 0: 0, 1: 0, 2: 0 }, outputs: { 0: 0, 1: 0 } },
            { inputs: { 0: 0, 1: 0, 2: 1 }, outputs: { 0: 1, 1: 0 } },
            { inputs: { 0: 0, 1: 1, 2: 0 }, outputs: { 0: 1, 1: 0 } },
            { inputs: { 0: 0, 1: 1, 2: 1 }, outputs: { 0: 0, 1: 1 } },
            { inputs: { 0: 1, 1: 0, 2: 0 }, outputs: { 0: 1, 1: 0 } },
            { inputs: { 0: 1, 1: 0, 2: 1 }, outputs: { 0: 0, 1: 1 } },
            { inputs: { 0: 1, 1: 1, 2: 0 }, outputs: { 0: 0, 1: 1 } },
            { inputs: { 0: 1, 1: 1, 2: 1 }, outputs: { 0: 1, 1: 1 } }
        ],
        hints: ['A full adder = two half adders + OR for the carry.', 'Sum = A XOR B XOR Cin. Cout = (A AND B) OR (Cin AND (A XOR B)).'],
        difficulty: 4
    },
    {
        id: 'half_subtractor',
        category: 'Arithmetic',
        title: 'Half Subtractor',
        description: 'Build A minus B. Outputs: Difference (A XOR B) and Borrow (NOT A AND B).',
        availableGates: ['INPUT', 'OUTPUT', 'AND', 'XOR', 'NOT'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 0, 1: 0 } },  // 0-0: diff=0, borrow=0
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 1, 1: 1 } },  // 0-1: diff=1, borrow=1
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 1, 1: 0 } },  // 1-0: diff=1, borrow=0
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 0, 1: 0 } }   // 1-1: diff=0, borrow=0
        ],
        hints: ['Difference = A XOR B (same as addition!).', 'Borrow = (NOT A) AND B.'],
        difficulty: 2
    },
    {
        id: 'comparator',
        category: 'Arithmetic',
        title: '1-bit Comparator',
        description: 'Compare A and B. Three outputs: A>B, A=B, A<B.',
        availableGates: ['INPUT', 'OUTPUT', 'AND', 'OR', 'NOT', 'XOR'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 0, 1: 1, 2: 0 } },  // 0=0: GT=0, EQ=1, LT=0
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 0, 1: 0, 2: 1 } },  // 0<1: GT=0, EQ=0, LT=1
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 1, 1: 0, 2: 0 } },  // 1>0: GT=1, EQ=0, LT=0
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 0, 1: 1, 2: 0 } }   // 1=1: GT=0, EQ=1, LT=0
        ],
        hints: ['A>B = A AND NOT B.', 'A=B = NOT(A XOR B) = XNOR.', 'A<B = NOT A AND B.'],
        difficulty: 3
    },
    // ============ Decoders & Encoders ============
    {
        id: 'decoder_2to4',
        category: 'Decoders & Encoders',
        title: '2-to-4 Decoder',
        description: 'Decode 2 input bits into 4 output lines. Only one output is 1 at a time.',
        availableGates: ['INPUT', 'OUTPUT', 'AND', 'NOT'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 1, 1: 0, 2: 0, 3: 0 } },  // 00 → line 0
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 0, 1: 1, 2: 0, 3: 0 } },  // 01 → line 1
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 0, 1: 0, 2: 1, 3: 0 } },  // 10 → line 2
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 0, 1: 0, 2: 0, 3: 1 } }   // 11 → line 3
        ],
        hints: ['Q0 = NOT A AND NOT B.', 'Q1 = NOT A AND B. Q2 = A AND NOT B. Q3 = A AND B.', 'You need 2 NOT gates and 4 AND gates.'],
        difficulty: 3
    },
    {
        id: 'encoder_4to2',
        category: 'Decoders & Encoders',
        title: '4-to-2 Encoder',
        description: 'Encode 4 input lines into 2-bit binary. Assume only one input is active at a time.',
        availableGates: ['INPUT', 'OUTPUT', 'OR'],
        testCases: [
            { inputs: { 0: 1, 1: 0, 2: 0, 3: 0 }, outputs: { 0: 0, 1: 0 } },  // line 0 → 00
            { inputs: { 0: 0, 1: 1, 2: 0, 3: 0 }, outputs: { 0: 0, 1: 1 } },  // line 1 → 01
            { inputs: { 0: 0, 1: 0, 2: 1, 3: 0 }, outputs: { 0: 1, 1: 0 } },  // line 2 → 10
            { inputs: { 0: 0, 1: 0, 2: 0, 3: 1 }, outputs: { 0: 1, 1: 1 } }   // line 3 → 11
        ],
        hints: ['Bit 1 (MSB) = Input2 OR Input3.', 'Bit 0 (LSB) = Input1 OR Input3.', 'Just 2 OR gates!'],
        difficulty: 2
    },
    {
        id: 'seven_seg_a',
        category: 'Decoders & Encoders',
        title: '7-Segment: Segment A',
        description: 'Drive segment A of a 7-segment display for digits 0-3. Segment A is ON for 0, 2, 3.',
        availableGates: ['INPUT', 'OUTPUT', 'AND', 'OR', 'NOT'],
        testCases: [
            { inputs: { 0: 0, 1: 0 }, outputs: { 0: 1 } },  // 0 → A on
            { inputs: { 0: 0, 1: 1 }, outputs: { 0: 0 } },  // 1 → A off
            { inputs: { 0: 1, 1: 0 }, outputs: { 0: 1 } },  // 2 → A on
            { inputs: { 0: 1, 1: 1 }, outputs: { 0: 1 } }   // 3 → A on
        ],
        hints: ['A = NOT(NOT A1 AND A0). Or equivalently: A = A1 OR NOT A0.'],
        difficulty: 2
    },
    // ============ Components ============
    {
        id: 'two_bit_adder',
        category: 'Components',
        title: '2-bit Adder',
        description: 'Chain two full adders to add two 2-bit numbers.',
        availableGates: ['INPUT', 'OUTPUT', 'FULL_ADDER'],
        testCases: [
            { inputs: { 0: 0, 1: 0, 2: 0, 3: 0 }, outputs: { 0: 0, 1: 0, 2: 0 } },
            { inputs: { 0: 0, 1: 0, 2: 0, 3: 1 }, outputs: { 0: 0, 1: 0, 2: 1 } },
            { inputs: { 0: 0, 1: 1, 2: 0, 3: 1 }, outputs: { 0: 0, 1: 1, 2: 1 } },
            { inputs: { 0: 1, 1: 1, 2: 0, 3: 1 }, outputs: { 0: 1, 1: 1, 2: 1 } },
            { inputs: { 0: 1, 1: 1, 2: 1, 3: 1 }, outputs: { 0: 0, 1: 1, 2: 1 } }
        ],
        hints: ['Use two FULL_ADDER components chained together.', 'First adder has no carry-in (set to 0).'],
        difficulty: 3
    },
    {
        id: 'alu_1bit',
        category: 'Components',
        title: '1-bit ALU',
        description: 'Build a 1-bit ALU. OP=0 → AND, OP=1 → OR. Inputs: A (0), B (1), OP (2).',
        availableGates: ['INPUT', 'OUTPUT', 'AND', 'OR', 'NOT'],
        testCases: [
            { inputs: { 0: 0, 1: 0, 2: 0 }, outputs: { 0: 0 } },  // 0 AND 0 = 0
            { inputs: { 0: 1, 1: 0, 2: 0 }, outputs: { 0: 0 } },  // 1 AND 0 = 0
            { inputs: { 0: 1, 1: 1, 2: 0 }, outputs: { 0: 1 } },  // 1 AND 1 = 1
            { inputs: { 0: 0, 1: 0, 2: 1 }, outputs: { 0: 0 } },  // 0 OR 0 = 0
            { inputs: { 0: 1, 1: 0, 2: 1 }, outputs: { 0: 1 } },  // 1 OR 0 = 1
            { inputs: { 0: 0, 1: 1, 2: 1 }, outputs: { 0: 1 } },  // 0 OR 1 = 1
            { inputs: { 0: 1, 1: 1, 2: 1 }, outputs: { 0: 1 } }   // 1 OR 1 = 1
        ],
        hints: ['Compute both A AND B and A OR B, then use a MUX to select based on OP.', 'MUX = (result0 AND NOT OP) OR (result1 AND OP).'],
        difficulty: 3
    }
];

// Progress tracking — load from localStorage if available
function loadProgress() {
    try {
        const saved = localStorage.getItem('logiclab_progress');
        if (saved) {
            const parsed = JSON.parse(saved);
            return {
                unlockedLevels: parsed.unlockedLevels || ['buffer'],
                completedLevels: parsed.completedLevels || [],
                currentLevel: null,
                customComponents: parsed.customComponents || {}
            };
        }
    } catch (e) { /* ignore parse errors */ }
    return {
        unlockedLevels: ['buffer'],
        completedLevels: [],
        currentLevel: null,
        customComponents: {}
    };
}

function saveProgress() {
    try {
        localStorage.setItem('logiclab_progress', JSON.stringify({
            unlockedLevels: progress.unlockedLevels,
            completedLevels: progress.completedLevels,
            customComponents: progress.customComponents
        }));
    } catch (e) { /* ignore storage errors */ }
}

export const progress = loadProgress();

/**
 * Get all available levels for display
 */
export function getAllLevels() {
    return LEVELS;
}

/**
 * Get a level by ID
 */
export function getLevel(id) {
    return LEVELS.find(l => l.id === id);
}

/**
 * Check if a level is unlocked
 */
export function isLevelUnlocked(levelId) {
    return progress.unlockedLevels.includes(levelId);
}

/**
 * Check if a level is completed
 */
export function isLevelCompleted(levelId) {
    return progress.completedLevels.includes(levelId);
}

/**
 * Verify if the current circuit passes all test cases for a level
 */
export function verifyLevel(levelId) {
    const level = getLevel(levelId);
    if (!level) return { passed: false, results: [], message: 'Level not found' };

    const results = [];
    let allPassed = true;

    for (const testCase of level.testCases) {
        const result = runTestCase(level, testCase);
        results.push(result);
        if (!result.passed) allPassed = false;
    }

    return {
        passed: allPassed,
        results,
        message: allPassed ? 'All tests passed! ✓' : `${results.filter(r => r.passed).length}/${results.length} tests passed`
    };
}

/**
 * Run a single test case
 */
function runTestCase(level, testCase) {
    // Find INPUT gates
    const inputGates = state.gates.filter(g => g.type === 'INPUT');
    // Find OUTPUT gates
    const outputGates = state.gates.filter(g => g.type === 'OUTPUT');

    // Check if we have the right number of inputs and outputs
    const inputIds = Object.keys(testCase.inputs).map(Number).sort((a, b) => a - b);
    const outputIds = Object.keys(testCase.outputs).map(Number).sort((a, b) => a - b);

    if (inputGates.length !== inputIds.length || outputGates.length !== outputIds.length) {
        return {
            passed: false,
            inputs: testCase.inputs,
            expectedOutputs: testCase.outputs,
            actualOutputs: {},
            error: `Expected ${inputIds.length} inputs and ${outputIds.length} outputs, got ${inputGates.length} and ${outputGates.length}`
        };
    }

    // Set input values
    for (let i = 0; i < inputIds.length; i++) {
        if (inputGates[i]) {
            inputGates[i].value = testCase.inputs[i];
        }
    }

    // Evaluate circuit
    state.gates.forEach(g => {
        if (g.type !== 'INPUT' && g.type !== 'CLOCK') g.value = 0;
    });
    state.gates.forEach(g => evaluate(g));

    // Check outputs
    const expected = testCase.outputs;
    let passed = true;
    const actualOutputs = {};

    for (let i = 0; i < outputIds.length; i++) {
        const actualValue = outputGates[i]?.value || 0;
        actualOutputs[i] = actualValue;
        if (actualValue !== expected[i]) {
            passed = false;
        }
    }

    return {
        passed,
        inputs: testCase.inputs,
        expectedOutputs: expected,
        actualOutputs
    };
}

/**
 * Complete a level and unlock the next one
 */
export function completeLevel(levelId) {
    const levelIndex = LEVELS.findIndex(l => l.id === levelId);
    if (levelIndex >= 0 && !progress.completedLevels.includes(levelId)) {
        progress.completedLevels.push(levelId);
    }

    // Unlock next level
    if (levelIndex < LEVELS.length - 1) {
        const nextId = LEVELS[levelIndex + 1].id;
        if (!progress.unlockedLevels.includes(nextId)) {
            progress.unlockedLevels.push(nextId);
        }
    }

    saveProgress();
}

/**
 * Register a custom component (saved circuit)
 */
export function registerComponent(name, gateTypes, connections) {
    progress.customComponents[name] = {
        name,
        gateTypes,
        connections
    };
    saveProgress();
}

/**
 * Get a custom component
 */
export function getComponent(name) {
    return progress.customComponents[name];
}

/**
 * Get all custom components
 */
export function getAllComponents() {
    return progress.customComponents;
}

/**
 * Reset progress (dev/testing)
 */
export function resetProgress() {
    progress.unlockedLevels = ['buffer'];
    progress.completedLevels = [];
    progress.currentLevel = null;
    progress.customComponents = {};
    saveProgress();
}