"""Synthetic one-zone water-vapour balance; Python 3.10+ stdlib only."""
import json, math, sys
from pathlib import Path

R_V = 461.5
BOUNDS = {
 "duration_hours":(.1,168),"time_step_seconds":(1,3600),"room_volume_m3":(1,1e7),
 "air_temperature_c":(-10,60),"initial_rh_pct":(0,100),"outside_rh_pct":(0,100),
 "ventilation_m3_per_s":(0,1e5),"transpiration_lit_kg_per_h":(0,1e5),
 "transpiration_dark_kg_per_h":(0,1e5),"lights_on_hour":(0,24),"lights_off_hour":(0,24),
 "dehumidifier_capacity_kg_per_h":(0,1e5),"dehumidifier_on_rh_pct":(0,100),
 "dehumidifier_off_rh_pct":(0,100),"latent_heat_j_per_kg":(1e5,5e6)}

def num(v,k,lo,hi):
 if isinstance(v,bool): raise ValueError(k+': boolean')
 try: v=float(v)
 except (TypeError,ValueError): raise ValueError(k+': nonnumeric') from None
 if not math.isfinite(v) or not lo<=v<=hi: raise ValueError(f'{k}: expected [{lo}, {hi}]')
 return v

def validate(raw):
 if set(raw)!=set(BOUNDS):
  raise ValueError('keys must match contract; missing='+str(sorted(set(BOUNDS)-set(raw)))+' unknown='+str(sorted(set(raw)-set(BOUNDS))))
 c={k:num(raw[k],k,*b) for k,b in BOUNDS.items()}
 if c['lights_off_hour']<=c['lights_on_hour']: raise ValueError('lights_off_hour must exceed lights_on_hour')
 if c['dehumidifier_off_rh_pct']>=c['dehumidifier_on_rh_pct']: raise ValueError('off threshold must be below on threshold')
 n=c['duration_hours']*3600/c['time_step_seconds']
 if abs(n-round(n))>1e-9: raise ValueError('duration must contain integer steps')
 return c

def saturation_pressure_pa(t): return 610.8*math.exp(17.27*t/(t+237.3))
def vapour_density(t,rh): return saturation_pressure_pa(t)*(rh/100)/(R_V*(t+273.15))
def rh_from_mass(t,mass,volume): return 100*(mass/volume)*R_V*(t+273.15)/saturation_pressure_pa(t)

def simulate(raw):
 c=validate(raw); dt=c['time_step_seconds']; steps=round(c['duration_hours']*3600/dt)
 mass=vapour_density(c['air_temperature_c'],c['initial_rh_pct'])*c['room_volume_m3']
 outside=vapour_density(c['air_temperature_c'],c['outside_rh_pct'])
 saturation=vapour_density(c['air_temperature_c'],100)*c['room_volume_m3']
 dehum=False; totals={k:0.0 for k in ('transpired','vented_net','dehumidified','condensed')}; residual=0.0; lo=hi=c['initial_rh_pct']; hourly=[]
 for i in range(steps):
  hour=i*dt/3600; rh=rh_from_mass(c['air_temperature_c'],mass,c['room_volume_m3'])
  if dehum and rh<=c['dehumidifier_off_rh_pct']: dehum=False
  elif not dehum and rh>=c['dehumidifier_on_rh_pct']: dehum=True
  lit=c['lights_on_hour']<=hour%24<c['lights_off_hour']
  transp=(c['transpiration_lit_kg_per_h'] if lit else c['transpiration_dark_kg_per_h'])/3600
  vent=c['ventilation_m3_per_s']*((mass/c['room_volume_m3'])-outside)
  removal=c['dehumidifier_capacity_kg_per_h']/3600 if dehum else 0
  before=mass; proposed=mass+(transp-vent-removal)*dt
  if proposed<0: raise ValueError('time step/removal drives vapour mass negative')
  condensation=max(0.0,proposed-saturation); mass=proposed-condensation
  residual+=abs((mass-before)-((transp-vent-removal)*dt-condensation))
  totals['transpired']+=transp*dt; totals['vented_net']+=vent*dt; totals['dehumidified']+=removal*dt; totals['condensed']+=condensation
  rh=rh_from_mass(c['air_temperature_c'],mass,c['room_volume_m3']); lo=min(lo,rh); hi=max(hi,rh)
  if (i+1)%round(3600/dt)==0: hourly.append({'hour':round((i+1)*dt/3600,6),'rh_pct':round(rh,6),'vapour_mass_kg':round(mass,6),'dehumidifier_on':dehum})
 return {'model':'one well-mixed vapour mass; fixed air temperature; synthetic inputs','minimum_rh_pct':lo,'maximum_rh_pct':hi,'final_rh_pct':rh_from_mass(c['air_temperature_c'],mass,c['room_volume_m3']),'final_vapour_mass_kg':mass,**{k+'_kg':v for k,v in totals.items()},'transpiration_latent_load_kwh':totals['transpired']*c['latent_heat_j_per_kg']/3.6e6,'removed_water_latent_load_kwh':(totals['dehumidified']+totals['condensed'])*c['latent_heat_j_per_kg']/3.6e6,'absolute_water_balance_residual_kg':residual,'hourly':hourly}

if __name__=='__main__':
 try:
  p=Path(sys.argv[1]) if len(sys.argv)>1 else Path(__file__).with_name('config.json')
  print(json.dumps(simulate(json.loads(p.read_text())),indent=2,allow_nan=False))
 except (OSError,ValueError,json.JSONDecodeError) as e: raise SystemExit('Invalid input: '+str(e)) from None