import { useState, useEffect, useMemo } from 'react'
import {
  calcOrbit,
  calcPowerBudget,
  calcLinkBudget,
  calcThermalBalance,
  calcMassBudget,
} from '../engine/satelliteCalcs.js'

const LS_KEY = 'rockettools_satellite'

const DEFAULTS = {
  orbitInputs: {
    altitudeKm:    500,
    betaAngleDeg:  0,
  },
  powerInputs: {
    formFactor:           '3U',
    solarCellType:        'GaAs',
    etaCell:              0.28,
    etaPacking:           0.85,
    deployablePanelArea:  0,
    etaCharge:            0.95,
    etaDischarge:         0.97,
    DOD:                  0.30,
    P_sunlight_load:      3.0,
    P_eclipse_load:       2.0,
    degradationPerYear:  -0.03,
    designLife:           2,
  },
  linkInputs: {
    P_tx_W:            1.0,
    G_tx_dBi:          6.0,
    L_feed_dB:         1.0,
    frequencyMHz:      437,
    modulation:       'BPSK',
    elevationAngleDeg: 5,
    L_atm_dB:          0.5,
    L_point_dB:        1.0,
    G_rx_dBi:          12.0,
    T_sys_K:           290,
    dataRateBps:       9600,
    Eb_N0_req_dB:      9.6,
  },
  thermalInputs: {
    alpha:    0.90,
    epsilon:  0.85,
    A_sun:    0.01,
    A_earth:  0.01,
    A_rad:    0.02,
    Q_int:    3.0,
  },
  subsystems: {
    adcs: {
      controlMode:          'sun-pointing',
      pointingAccuracyDeg:  5,
      reactionWheels:       false,
      magnetorquers:        true,
      mass:      200,
      avgPower:  0.5,
      peakPower: 1.0,
    },
    comms: {
      frequencyMHz: 437,
      P_tx_W:       1.0,
      antennaType: 'dipole',
      modulation:  'BPSK',
      mass:      100,
      avgPower:  1.0,
      peakPower: 2.0,
    },
    cdh: {
      processor:            'ARM Cortex-M4',
      storageGB:            2,
      housekeepingRateHz:   1,
      mass:      120,
      avgPower:  0.8,
      peakPower: 1.2,
    },
    eps: {
      batteryChemistry: 'Li-ion',
      solarCellType:    'GaAs',
      mass:             300,
    },
    structure: {
      materialId:    'al_6061_t6',
      configuration: 'standard',
      mass:           400,
    },
    propulsion: {
      type:       'none',
      propellant: '',
      mass:       0,
      avgPower:   0,
      peakPower:  0,
    },
    payload: {
      name:      '',
      type:      '',
      mass:       0,
      avgPower:   0,
      peakPower:  0,
      interface: 'UART',
    },
  },
}

function loadFromStorage() {
  try {
    const raw = localStorage.getItem(LS_KEY)
    return raw ? JSON.parse(raw) : null
  } catch {
    return null
  }
}

export function useSatelliteDesign() {
  const saved = useMemo(() => loadFromStorage(), [])

  const [orbitInputs,   setOrbitInputs]   = useState(saved?.orbitInputs   ?? DEFAULTS.orbitInputs)
  const [powerInputs,   setPowerInputs]   = useState(saved?.powerInputs   ?? DEFAULTS.powerInputs)
  const [linkInputs,    setLinkInputs]    = useState(saved?.linkInputs    ?? DEFAULTS.linkInputs)
  const [thermalInputs, setThermalInputs] = useState(saved?.thermalInputs ?? DEFAULTS.thermalInputs)
  const [subsystems,    setSubsystems]    = useState(saved?.subsystems    ?? DEFAULTS.subsystems)

  // Persist all state slices on any change
  useEffect(() => {
    try {
      localStorage.setItem(LS_KEY, JSON.stringify({
        orbitInputs, powerInputs, linkInputs, thermalInputs, subsystems,
      }))
    } catch {}
  }, [orbitInputs, powerInputs, linkInputs, thermalInputs, subsystems])

  // ── Calculation chain (pure useMemo, no side effects) ──
  const orbitData      = useMemo(() => calcOrbit(orbitInputs),                          [orbitInputs])
  const powerBudget    = useMemo(() => calcPowerBudget(orbitData, powerInputs),          [orbitData, powerInputs])
  const linkBudget     = useMemo(() => calcLinkBudget(orbitData, linkInputs),            [orbitData, linkInputs])
  const thermalBalance = useMemo(() => calcThermalBalance(orbitData, thermalInputs),     [orbitData, thermalInputs])
  const massBudget     = useMemo(() => calcMassBudget(subsystems, powerInputs.formFactor), [subsystems, powerInputs.formFactor])

  // ── Setters ──

  /** Patch a single key in orbitInputs */
  function setOrbitInput(key, value) {
    setOrbitInputs(prev => ({ ...prev, [key]: value }))
  }

  /** Patch a single key in powerInputs */
  function setPowerInput(key, value) {
    setPowerInputs(prev => ({ ...prev, [key]: value }))
  }

  /** Patch a single key in linkInputs */
  function setLinkInput(key, value) {
    setLinkInputs(prev => ({ ...prev, [key]: value }))
  }

  /** Patch a single key in thermalInputs */
  function setThermalInput(key, value) {
    setThermalInputs(prev => ({ ...prev, [key]: value }))
  }

  /** Patch one or more fields of a specific subsystem */
  function setSubsystem(key, patch) {
    setSubsystems(prev => ({ ...prev, [key]: { ...prev[key], ...patch } }))
  }

  return {
    // State slices
    orbitInputs,   setOrbitInput,
    powerInputs,   setPowerInput,
    linkInputs,    setLinkInput,
    thermalInputs, setThermalInput,
    subsystems,    setSubsystem,

    // Computed results
    orbitData,
    powerBudget,
    linkBudget,
    thermalBalance,
    massBudget,
  }
}