/**
 * VERIFICATION & VALIDATION SYSTEM
 *
 * Proves the metaverse simulation is correct by comparing against:
 * - JPL Horizons ephemerides (real astronomical positions)
 * - Physics benchmarks (energy conservation, orbital mechanics)
 * - WGS84 geodesy (Earth coordinates)
 * - Known celestial events (eclipses, conjunctions, transits)
 *
 * Philosophy: "TRUTH IS MEASURABLE. WE VERIFY AGAINST REALITY."
 */

import * as THREE from 'three';

// ===== ASTRONOMICAL CONSTANTS (J2000.0 Epoch) =====
export const ASTRO_CONSTANTS = {
    // Gravitational parameter (km³/s²)
    GM_SUN: 1.32712440018e11,
    GM_EARTH: 3.986004418e5,
    GM_MOON: 4.9028e3,

    // Astronomical Unit (km)
    AU: 149597870.7,

    // Light speed (km/s)
    C: 299792.458,

    // J2000.0 epoch
    J2000: 2451545.0, // Julian Date

    // Earth rotation
    EARTH_SIDEREAL_DAY: 86164.0905, // seconds
    EARTH_AXIAL_TILT: 23.4397, // degrees

    // Orbital elements (simplified, mean values for verification)
    EARTH_ORBIT: {
        a: 1.00000011, // AU
        e: 0.01671022,
        i: 0.00005, // degrees
        period: 365.256363004 // days
    },

    MOON_ORBIT: {
        a: 384400, // km
        e: 0.0549,
        i: 5.145, // degrees to ecliptic
        period: 27.321661 // days
    }
};

// ===== KNOWN CELESTIAL EVENTS FOR VALIDATION =====
export const KNOWN_EVENTS = {
    // Solar eclipses
    solar_eclipse_2024: {
        date: new Date('2024-04-08T18:17:00Z'),
        type: 'total_solar_eclipse',
        location: { lat: 29.9, lon: -99.8 }, // Texas
        duration: 268, // seconds of totality
        tolerance: 60 // seconds
    },

    // Lunar eclipses
    lunar_eclipse_2025: {
        date: new Date('2025-03-14T06:59:00Z'),
        type: 'total_lunar_eclipse',
        magnitude: 1.178,
        tolerance: 0.01
    },

    // Planetary conjunctions
    jupiter_saturn_2020: {
        date: new Date('2020-12-21T18:20:00Z'),
        type: 'great_conjunction',
        separation: 0.1, // degrees
        tolerance: 0.05
    },

    // Equinoxes & Solstices
    spring_equinox_2025: {
        date: new Date('2025-03-20T09:01:00Z'),
        type: 'vernal_equinox',
        tolerance: 60 * 60 // 1 hour
    },

    summer_solstice_2025: {
        date: new Date('2025-06-20T22:42:00Z'),
        type: 'summer_solstice',
        tolerance: 60 * 60
    }
};

// ===== WGS84 REFERENCE POINTS =====
export const WGS84_LANDMARKS = {
    greenwich: {
        name: 'Greenwich Observatory',
        lat: 51.4769,
        lon: -0.0005,
        elevation: 46
    },
    north_pole: {
        name: 'Geographic North Pole',
        lat: 90.0,
        lon: 0.0,
        elevation: 0
    },
    equator_null_island: {
        name: 'Null Island (0°N 0°E)',
        lat: 0.0,
        lon: 0.0,
        elevation: 0
    },
    mount_everest: {
        name: 'Mount Everest Summit',
        lat: 27.9881,
        lon: 86.9250,
        elevation: 8848.86
    }
};

// ===== PHYSICS BENCHMARKS =====
export const PHYSICS_BENCHMARKS = {
    // Two-body problem (Earth-Moon system)
    earth_moon_2body: {
        description: 'Earth-Moon barycentric orbit',
        initial_conditions: {
            earth_pos: [0, 0, 0],
            moon_pos: [384400, 0, 0], // km
            moon_vel: [0, 1.022, 0] // km/s
        },
        expected: {
            period: 27.321661, // days
            tolerance: 0.01
        }
    },

    // Energy conservation test
    energy_conservation: {
        description: 'Total energy should remain constant',
        tolerance: 1e-6 // relative error
    },

    // Angular momentum conservation
    angular_momentum: {
        description: 'Angular momentum should remain constant',
        tolerance: 1e-8
    },

    // Kepler's 3rd law
    keplers_third_law: {
        description: 'T² ∝ a³ for all planets',
        tolerance: 0.001
    }
};

// ===== VERIFICATION MANAGER =====
export class VerificationManager {
    constructor() {
        this.testResults = [];
        this.passed = 0;
        this.failed = 0;
        this.warnings = 0;
    }

    // ===== ASTRONOMICAL VERIFICATION =====

    /**
     * Verify celestial body position against JPL Horizons data
     */
    verifyPosition(bodyName, simulated, reference, timestamp) {
        const test = {
            name: `Position: ${bodyName} at ${timestamp}`,
            type: 'position',
            timestamp
        };

        // Calculate position error
        const error = {
            x: Math.abs(simulated.x - reference.x),
            y: Math.abs(simulated.y - reference.y),
            z: Math.abs(simulated.z - reference.z)
        };

        const totalError = Math.sqrt(
            error.x * error.x +
            error.y * error.y +
            error.z * error.z
        );

        // Tolerance: 1000 km for planets, 10 km for moon
        const tolerance = bodyName === 'moon' ? 10 : 1000;

        test.passed = totalError < tolerance;
        test.error = totalError;
        test.tolerance = tolerance;
        test.details = {
            simulated,
            reference,
            error
        };

        this.recordTest(test);
        return test;
    }

    /**
     * Verify celestial event timing
     */
    verifyCelestialEvent(eventId, simulatedTime) {
        const event = KNOWN_EVENTS[eventId];
        if (!event) {
            console.error(`Unknown event: ${eventId}`);
            return null;
        }

        const test = {
            name: `Event: ${event.type}`,
            type: 'event',
            eventId
        };

        const expectedTime = event.date.getTime();
        const actualTime = simulatedTime.getTime();
        const error = Math.abs(actualTime - expectedTime) / 1000; // seconds

        test.passed = error < event.tolerance;
        test.error = error;
        test.tolerance = event.tolerance;
        test.details = {
            expected: event.date,
            simulated: simulatedTime,
            errorSeconds: error
        };

        this.recordTest(test);
        return test;
    }

    /**
     * Verify orbital period
     */
    verifyOrbitalPeriod(bodyName, simulatedPeriod, referencePeriod, tolerance = 0.01) {
        const test = {
            name: `Orbital Period: ${bodyName}`,
            type: 'orbital_period'
        };

        const error = Math.abs(simulatedPeriod - referencePeriod) / referencePeriod;

        test.passed = error < tolerance;
        test.error = error;
        test.tolerance = tolerance;
        test.details = {
            simulated: simulatedPeriod,
            reference: referencePeriod,
            relativeError: error
        };

        this.recordTest(test);
        return test;
    }

    // ===== PHYSICS VERIFICATION =====

    /**
     * Verify energy conservation in N-body system
     */
    verifyEnergyConservation(initialEnergy, currentEnergy, tolerance = 1e-6) {
        const test = {
            name: 'Energy Conservation',
            type: 'physics'
        };

        const relativeChange = Math.abs(currentEnergy - initialEnergy) / Math.abs(initialEnergy);

        test.passed = relativeChange < tolerance;
        test.error = relativeChange;
        test.tolerance = tolerance;
        test.details = {
            initial: initialEnergy,
            current: currentEnergy,
            change: relativeChange
        };

        this.recordTest(test);
        return test;
    }

    /**
     * Verify angular momentum conservation
     */
    verifyAngularMomentum(initialL, currentL, tolerance = 1e-8) {
        const test = {
            name: 'Angular Momentum Conservation',
            type: 'physics'
        };

        const change = {
            x: Math.abs(currentL.x - initialL.x),
            y: Math.abs(currentL.y - initialL.y),
            z: Math.abs(currentL.z - initialL.z)
        };

        const totalChange = Math.sqrt(
            change.x * change.x +
            change.y * change.y +
            change.z * change.z
        );

        const initialMagnitude = Math.sqrt(
            initialL.x * initialL.x +
            initialL.y * initialL.y +
            initialL.z * initialL.z
        );

        const relativeChange = totalChange / initialMagnitude;

        test.passed = relativeChange < tolerance;
        test.error = relativeChange;
        test.tolerance = tolerance;
        test.details = {
            initial: initialL,
            current: currentL,
            change: relativeChange
        };

        this.recordTest(test);
        return test;
    }

    /**
     * Verify Kepler's 3rd Law: T² ∝ a³
     */
    verifyKeplersThirdLaw(bodies) {
        const test = {
            name: "Kepler's 3rd Law",
            type: 'physics'
        };

        let maxError = 0;

        bodies.forEach(body => {
            const expected = Math.pow(body.period, 2) / Math.pow(body.semiMajorAxis, 3);
            // For Sun-centered orbits, this should equal 4π²/GM☉
            const theoretical = (4 * Math.PI * Math.PI) / ASTRO_CONSTANTS.GM_SUN;
            const error = Math.abs(expected - theoretical) / theoretical;
            maxError = Math.max(maxError, error);
        });

        test.passed = maxError < 0.001;
        test.error = maxError;
        test.tolerance = 0.001;

        this.recordTest(test);
        return test;
    }

    // ===== GEODESY VERIFICATION =====

    /**
     * Verify WGS84 coordinate transformation
     */
    verifyWGS84Transform(landmark, simulatedXYZ) {
        const ref = WGS84_LANDMARKS[landmark];
        if (!ref) {
            console.error(`Unknown landmark: ${landmark}`);
            return null;
        }

        const test = {
            name: `WGS84: ${ref.name}`,
            type: 'geodesy'
        };

        // Convert lat/lon/elevation to ECEF (Earth-Centered Earth-Fixed)
        const expectedXYZ = this.latLonToECEF(ref.lat, ref.lon, ref.elevation);

        const error = {
            x: Math.abs(simulatedXYZ.x - expectedXYZ.x),
            y: Math.abs(simulatedXYZ.y - expectedXYZ.y),
            z: Math.abs(simulatedXYZ.z - expectedXYZ.z)
        };

        const totalError = Math.sqrt(
            error.x * error.x +
            error.y * error.y +
            error.z * error.z
        );

        // Tolerance: 10 meters
        const tolerance = 0.01; // km

        test.passed = totalError < tolerance;
        test.error = totalError;
        test.tolerance = tolerance;
        test.details = {
            landmark: ref,
            simulated: simulatedXYZ,
            expected: expectedXYZ,
            errorKm: totalError
        };

        this.recordTest(test);
        return test;
    }

    latLonToECEF(lat, lon, elevation) {
        // WGS84 parameters
        const a = 6378.137; // equatorial radius (km)
        const f = 1 / 298.257223563; // flattening
        const b = a * (1 - f); // polar radius
        const e2 = 1 - (b * b) / (a * a); // eccentricity squared

        const latRad = lat * Math.PI / 180;
        const lonRad = lon * Math.PI / 180;
        const h = elevation / 1000; // meters to km

        const N = a / Math.sqrt(1 - e2 * Math.sin(latRad) * Math.sin(latRad));

        return {
            x: (N + h) * Math.cos(latRad) * Math.cos(lonRad),
            y: (N + h) * Math.cos(latRad) * Math.sin(lonRad),
            z: (N * (1 - e2) + h) * Math.sin(latRad)
        };
    }

    // ===== TEST RECORDING & REPORTING =====

    recordTest(test) {
        this.testResults.push(test);

        if (test.passed) {
            this.passed++;
        } else {
            this.failed++;
        }

        // Log result
        const status = test.passed ? '✅' : '❌';
        console.log(`${status} ${test.name}: Error = ${test.error.toExponential(3)}, Tolerance = ${test.tolerance.toExponential(3)}`);
    }

    generateReport() {
        const total = this.testResults.length;
        const passRate = (this.passed / total * 100).toFixed(1);

        const report = {
            summary: {
                total,
                passed: this.passed,
                failed: this.failed,
                warnings: this.warnings,
                passRate: `${passRate}%`
            },
            tests: this.testResults,
            timestamp: new Date().toISOString()
        };

        console.log('\n📊 VERIFICATION REPORT');
        console.log('======================');
        console.log(`Total Tests: ${total}`);
        console.log(`Passed: ${this.passed} ✅`);
        console.log(`Failed: ${this.failed} ❌`);
        console.log(`Pass Rate: ${passRate}%`);
        console.log('======================\n');

        return report;
    }

    exportReport() {
        const report = this.generateReport();
        const json = JSON.stringify(report, null, 2);
        return json;
    }

    reset() {
        this.testResults = [];
        this.passed = 0;
        this.failed = 0;
        this.warnings = 0;
    }
}

// ===== JPL HORIZONS API INTERFACE =====
export class HorizonsAPI {
    /**
     * Fetch position data from JPL Horizons
     * (In production, this would make actual API calls)
     */
    async fetchPosition(bodyId, timestamp) {
        // Mock data for demonstration
        // In production, would call: https://ssd.jpl.nasa.gov/api/horizons.api

        console.log(`[MOCK] Fetching JPL Horizons data for body ${bodyId} at ${timestamp}`);

        // Return mock ephemeris data
        return {
            body: bodyId,
            timestamp,
            position: {
                x: 0, // km
                y: 0,
                z: 0
            },
            velocity: {
                x: 0,
                y: 0,
                z: 0
            },
            source: 'JPL_HORIZONS_MOCK'
        };
    }

    async fetchEphemeris(bodyId, startDate, endDate, stepSize = '1d') {
        console.log(`[MOCK] Fetching ephemeris for ${bodyId} from ${startDate} to ${endDate}`);

        return {
            body: bodyId,
            start: startDate,
            end: endDate,
            step: stepSize,
            data: [],
            source: 'JPL_HORIZONS_MOCK'
        };
    }
}

// ===== AUTOMATED TEST SUITE =====
export class AutomatedTestSuite {
    constructor(simulator) {
        this.simulator = simulator;
        this.verifier = new VerificationManager();
        this.horizons = new HorizonsAPI();
    }

    async runAllTests() {
        console.log('🧪 Running automated verification tests...\n');

        // Physics tests
        await this.testEnergyConservation();
        await this.testAngularMomentumConservation();
        await this.testKeplersThirdLaw();

        // Astronomical tests
        await this.testEarthPosition();
        await this.testMoonPosition();
        await this.testOrbitalPeriods();

        // Geodesy tests
        await this.testWGS84Landmarks();

        // Event prediction tests
        await this.testEventPredictions();

        // Generate report
        return this.verifier.generateReport();
    }

    async testEnergyConservation() {
        console.log('Testing energy conservation...');

        const initialEnergy = this.simulator.calculateTotalEnergy();

        // Run simulation for 1 orbit
        this.simulator.step(365.25); // days

        const finalEnergy = this.simulator.calculateTotalEnergy();

        this.verifier.verifyEnergyConservation(initialEnergy, finalEnergy);
    }

    async testAngularMomentumConservation() {
        console.log('Testing angular momentum conservation...');

        const initialL = this.simulator.calculateAngularMomentum();

        this.simulator.step(365.25);

        const finalL = this.simulator.calculateAngularMomentum();

        this.verifier.verifyAngularMomentum(initialL, finalL);
    }

    async testKeplersThirdLaw() {
        console.log("Testing Kepler's 3rd Law...");

        const bodies = this.simulator.getBodies();
        this.verifier.verifyKeplersThirdLaw(bodies);
    }

    async testEarthPosition() {
        console.log('Testing Earth position against JPL data...');

        const timestamp = new Date();
        const simulated = this.simulator.getPosition('earth');
        const reference = await this.horizons.fetchPosition('earth', timestamp);

        this.verifier.verifyPosition('earth', simulated, reference.position, timestamp);
    }

    async testMoonPosition() {
        console.log('Testing Moon position...');

        const timestamp = new Date();
        const simulated = this.simulator.getPosition('moon');
        const reference = await this.horizons.fetchPosition('moon', timestamp);

        this.verifier.verifyPosition('moon', simulated, reference.position, timestamp);
    }

    async testOrbitalPeriods() {
        console.log('Testing orbital periods...');

        const earthPeriod = this.simulator.measureOrbitalPeriod('earth');
        this.verifier.verifyOrbitalPeriod('earth', earthPeriod, 365.256363004);

        const moonPeriod = this.simulator.measureOrbitalPeriod('moon');
        this.verifier.verifyOrbitalPeriod('moon', moonPeriod, 27.321661);
    }

    async testWGS84Landmarks() {
        console.log('Testing WGS84 coordinate transformations...');

        ['greenwich', 'north_pole', 'equator_null_island', 'mount_everest'].forEach(landmark => {
            const simulated = this.simulator.getLandmarkPosition(landmark);
            this.verifier.verifyWGS84Transform(landmark, simulated);
        });
    }

    async testEventPredictions() {
        console.log('Testing celestial event predictions...');

        // Would test eclipse predictions, conjunctions, etc.
        // const predictedEclipse = this.simulator.predictNextEclipse();
        // this.verifier.verifyCelestialEvent('solar_eclipse_2024', predictedEclipse.time);
    }
}

export default {
    VerificationManager,
    HorizonsAPI,
    AutomatedTestSuite,
    ASTRO_CONSTANTS,
    KNOWN_EVENTS,
    WGS84_LANDMARKS,
    PHYSICS_BENCHMARKS
};