"""Synthetic well-mixed CO2 mole balance; Python 3.10+ stdlib only."""
import json,math,sys
from pathlib import Path
R=8.314462618; M=0.04401
LIMITS={"duration_hours":(.1,168),"time_step_seconds":(1,3600),"room_volume_m3":(1,1e7),"air_temperature_c":(-10,60),"pressure_pa":(50000,120000),"initial_co2_ppm":(0,10000),"outside_co2_ppm":(0,10000),"ventilation_m3_per_s":(0,1e5),"lights_on_hour":(0,24),"lights_off_hour":(0,24),"plant_uptake_lit_kg_per_h":(0,1e5),"respiration_dark_kg_per_h":(0,1e5),"injection_capacity_kg_per_h":(0,1e5),"injection_on_ppm":(0,10000),"injection_off_ppm":(0,10000)}
def number(v,k,a,b):
 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 a<=v<=b:raise ValueError(f'{k}: expected [{a}, {b}]')
 return v
def validate(x):
 if set(x)!=set(LIMITS):raise ValueError('keys must match contract')
 c={k:number(x[k],k,*b) for k,b in LIMITS.items()}
 if c['lights_off_hour']<=c['lights_on_hour']:raise ValueError('lights schedule')
 if c['injection_on_ppm']>=c['injection_off_ppm']:raise ValueError('injection thresholds')
 n=c['duration_hours']*3600/c['time_step_seconds']
 if abs(n-round(n))>1e-9:raise ValueError('integer steps required')
 return c
def air_moles(c):return c['pressure_pa']*c['room_volume_m3']/(R*(c['air_temperature_c']+273.15))
def simulate(raw):
 c=validate(raw); total=air_moles(c); n=total*c['initial_co2_ppm']/1e6; out=c['outside_co2_ppm']/1e6; dt=c['time_step_seconds']; on=False
 sums={'uptake':0.,'respiration':0.,'injection':0.,'ventilation_net':0.}; residual=0.; low=high=c['initial_co2_ppm']; hourly=[]
 for i in range(round(c['duration_hours']*3600/dt)):
  ppm=n/total*1e6
  if on and ppm>=c['injection_off_ppm']:on=False
  elif not on and ppm<=c['injection_on_ppm']:on=True
  h=i*dt/3600; lit=c['lights_on_hour']<=h%24<c['lights_off_hour']
  uptake=(c['plant_uptake_lit_kg_per_h']/M/3600) if lit else 0
  respiration=(c['respiration_dark_kg_per_h']/M/3600) if not lit else 0
  injection=(c['injection_capacity_kg_per_h']/M/3600) if on else 0
  vent=c['pressure_pa']*c['ventilation_m3_per_s']/(R*(c['air_temperature_c']+273.15))*(n/total-out)
  before=n; n+=(respiration+injection-uptake-vent)*dt
  if n<0:raise ValueError('negative CO2; reduce step or sink')
  residual+=abs((n-before)-(respiration+injection-uptake-vent)*dt)
  for k,v in [('uptake',uptake),('respiration',respiration),('injection',injection),('ventilation_net',vent)]:sums[k]+=v*dt*M
  ppm=n/total*1e6;low=min(low,ppm);high=max(high,ppm)
  if (i+1)%round(3600/dt)==0:hourly.append({'hour':round((i+1)*dt/3600,6),'co2_ppm':round(ppm,6),'injection_on':on})
 return {'model':'fixed T/P well-mixed ideal-gas CO2 mole balance; synthetic fluxes','minimum_co2_ppm':low,'maximum_co2_ppm':high,'final_co2_ppm':n/total*1e6,**{k+'_kg':v for k,v in sums.items()},'absolute_mole_balance_residual_mol':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