#!/bin/bash

##########################################################
# Radxa Rock 5C fan PWM control script
# Author: https:///github.com/c0m4r
# License: Public Domain
##########################################################

# PWM control path
PWM_PATH="/sys/devices/platform/pwm-fan/hwmon"

# Configuration
INTERVAL=10         # Temperature check interval (seconds)
FAN_OFF=1           # 1 = turn off fan below MIN_TEMP after cooldown, 0 = keep at min RPM
COOLDOWN=300        # time to wait before turning off the fan when FAN_OFF=1

# Critical temp protection
POWEROFF_ON_CRIT=1  # 1 = shutdown when the temperature reaches a critical value, 0 = disable
CRITICAL_TEMP=70    # Critical temperature (shutdown)

# PWM Values (proper)
SAFE_PWM_MIN=105    # Safe minimum PWM to keep fan spinning
PWM_LOW=125         # 45–50°C (~50% speed)
PWM_MID=165         # 50–55°C (~65% speed)
PWM_HIGH=200        # 55–60°C (~80% speed)
PWM_MAX=255         # >60°C (100% speed)

# PWM Values (temporary - use these instead of proper if the fan spins at max all the time)
#SAFE_PWM_MIN=50    # Safe minimum PWM to keep fan spinning
#PWM_LOW=60         # 45–50°C (~50% speed)
#PWM_MID=70         # 50–55°C (~65% speed)
#PWM_HIGH=80        # 55–60°C (~80% speed)
#PWM_MAX=255         # >60°C (100% speed)

# Constants (requires also changes in code)
MIN_TEMP=47         # Minimum temperature (PWM_MIN)
MAX_TEMP=60         # Maximum temperature (PWM_MAX)


# Set thermal policy
thermal_zones=$(ls -1 /sys/class/thermal | grep thermal_zone)

if [[ "$thermal_zones" ]]; then
  for i in /sys/class/thermal/thermal_zone*/policy ; do
    echo "user_space" > "$i"
  done
else
  echo "No sensors found, check kernel support, setting fan to high for now!"
  echo $PWM_HIGH > ${PWM_PATH}/hwmon*/pwm1
  exit 1
fi

# Set PWM_MIN based on FAN_OFF mode
if [ "$FAN_OFF" -eq 1 ]; then
  PWM_MIN=0 # Allow fan to turn off after cooldown
else
  PWM_MIN=$SAFE_PWM_MIN # Keep fan at minimal safe RPM all the time
fi

# Validate PWM path
if [ ! -d "$PWM_PATH" ]; then
  echo "Error: PWM control file not found: $PWM_PATH"
  exit 1
fi

# Initialize variables
current_pwm=$(cat ${PWM_PATH}/hwmon*/pwm1) # Start at current PWM
last_high_temp_time=0 # Track last high temp for cooldown
echo "Initializing fan at PWM $current_pwm"
echo "$current_pwm" > ${PWM_PATH}/hwmon*/pwm1

# Main loop
while true; do
  for i in /sys/class/thermal/thermal_zone*/policy ; do
    echo "user_space" > "$i"
  done

  # Get highest temperature (in °C)
  temp=$(cat /sys/class/thermal/thermal_zone*/temp | xargs -I{} expr {} / 1000 | sort -nr | head -n 1)

  # Critical temperature handling
  if [ "$POWEROFF_ON_CRIT" -eq 1 ] && [ "$temp" -ge "$CRITICAL_TEMP" ]; then
    echo "Critical temperature reached: ${temp}°C. Shutting down in 10 seconds..."
    sleep 10
    shutdown -h now  # Power off the system
    exit 0
  fi

  # Update last high temp timestamp if above cooldown threshold
  if [ "$temp" -ge $MIN_TEMP ]; then
    last_high_temp_time=$(date +%s)
  fi

  # Determine target PWM
  if [ "$temp" -ge $MAX_TEMP ]; then
    target_pwm=$PWM_MAX
  elif [ "$temp" -ge 55 ] && [ "$current_pwm" -lt $PWM_HIGH ]; then
    target_pwm=$PWM_HIGH
  elif [ "$temp" -ge 50 ] && [ "$current_pwm" -lt $PWM_MID ]; then
    target_pwm=$PWM_MID
  elif [ "$temp" -ge 47 ] && [ "$current_pwm" -lt $PWM_LOW ]; then
    target_pwm=$PWM_LOW
  elif [ "$temp" -lt 47 ]; then
    # Handle cooldown logic only if FAN_OFF=1
    if [ "$FAN_OFF" -eq 1 ]; then
      current_time=$(date +%s)
      time_since_high=$((current_time - last_high_temp_time))

      if [ "$time_since_high" -ge "$COOLDOWN" ]; then
        target_pwm=$PWM_MIN # after cooldown
      else
        target_pwm=$SAFE_PWM_MIN # during cooldown
      fi
    else
      target_pwm=$PWM_MIN # if FAN_OFF=0
    fi
  else
    target_pwm=$current_pwm # No change
  fi

  # Apply PWM changes if needed
  if [ "$target_pwm" -ne "$current_pwm" ]; then
    echo "Temp: ${temp}°C | PWM: $current_pwm → $target_pwm 🌡️"
    echo "$target_pwm" > ${PWM_PATH}/hwmon*/pwm1
    current_pwm=$target_pwm
  else
    echo "Temp: ${temp}°C | PWM: $current_pwm"
  fi

  sleep "$INTERVAL"
done