#!/usr/bin/env bash

cache_dir=~/.cache/tmux
cache_file=$cache_dir/system-info

# Make sure the output directory exists.
if [ ! -d $cache_dir ]; then
  mkdir -p $cache_dir
fi

if [ ! -f $cache_dir/cpu-temp ]; then
  clang -x objective-c -Wall -O2 -g -c -o $cache_dir/cpu-temp.o - << EOF
#import <Foundation/Foundation.h>
#import <IOKit/hidsystem/IOHIDEventSystemClient.h>
#include <unistd.h>

#define IOHIDEventFieldBase(type) (type << 16)
#define kIOHIDEventTypeTemperature 15

typedef struct __IOHIDEvent *IOHIDEventRef;
typedef struct __IOHIDServiceClient *IOHIDServiceClientRef;
typedef double IOHIDFloat;

IOHIDEventSystemClientRef
IOHIDEventSystemClientCreate(CFAllocatorRef allocator);
int IOHIDEventSystemClientSetMatching(IOHIDEventSystemClientRef client,
                                      CFDictionaryRef match);
IOHIDEventRef IOHIDServiceClientCopyEvent(IOHIDServiceClientRef, int64_t,
                                          int32_t, int64_t);
CFStringRef IOHIDServiceClientCopyProperty(IOHIDServiceClientRef service,
                                           CFStringRef property);
IOHIDFloat IOHIDEventGetFloatValue(IOHIDEventRef event, int32_t field);

int main(int argc, char *argv[]) {
  NSDictionary *thermalSensors = @{
    @"PrimaryUsagePage" : [NSNumber numberWithInt:0xFF00],
    @"PrimaryUsage" : [NSNumber numberWithInt:5],
  };
  IOHIDEventSystemClientRef system =
      IOHIDEventSystemClientCreate(kCFAllocatorDefault);
  IOHIDEventSystemClientSetMatching(system,
                                    (__bridge CFDictionaryRef)thermalSensors);
  NSArray *serviceClients =
      (__bridge NSArray *)IOHIDEventSystemClientCopyServices(system);

  long count = [serviceClients count];
  for (NSUInteger i = 0; i < count; i++) {
    IOHIDServiceClientRef serviceClient =
        (IOHIDServiceClientRef)serviceClients[i];
    NSString *name = (NSString *)IOHIDServiceClientCopyProperty(
        serviceClient, (__bridge CFStringRef) @"Product");
    if ([name isEqualToString:[NSString stringWithUTF8String:argv[1]]]) {
      IOHIDEventRef event = IOHIDServiceClientCopyEvent(
          serviceClient, kIOHIDEventTypeTemperature, 0, 0);
      NSNumber *value;
      double temp = 0.0;
      if (event != 0) {
        temp = IOHIDEventGetFloatValue(
            event, IOHIDEventFieldBase(kIOHIDEventTypeTemperature));
      }
      value = [NSNumber numberWithDouble:temp];
      printf("%.1lf°C\n", [value doubleValue]);
      break;
    }
  }

  return 0;
}
EOF
  clang -o $cache_dir/cpu-temp $cache_dir/cpu-temp.o -framework Foundation -framework IOKit
  rm $cache_dir/cpu-temp.o
fi

# Cleanup cache file when interrupted.
trap '[ -f $cache_file ] && rm $cache_file; exit' INT
trap '[ -f $cache_file ] && rm $cache_file; exit' TERM

# Check if a battery is installed.
ioreg -w0 -l | grep BatteryInstalled &> /dev/null && \
  has_battery=true || has_battery=false

while true; do
  # Get the current CPU temperature.
  cpu_temp="`$cache_dir/cpu-temp 'PMU tdie0'` "

  cpu_load=$(sudo powermetrics --format text \
      --sample-rate 1200 --sample-count 1 --samplers cpu_power |
    grep --color=never -E 'CPU \d idle residency:' |
    grep --color=never -Eo '\d+\.\d+' |
    gawk '$idle ~ /[-.0-9]*/ { printf "%s", substr("█▇▆▅▄▃▂▁ ", int($idle / 10), 1) }'
  )

  # Parse the current battery charge percentage.
  if $has_battery; then
    raw_battery="$(pmset -g batt | \
      grep --color=never 'InternalBattery' | \
      grep --color=never -Eo '\d+%' | \
      grep --color=never -Eo '\d+')"
    battery="$(echo $raw_battery | gawk '$battery ~ /.*/ {
      printf " %d%% %s\n", $battery, substr("󰂎󰁺󰁻󰁼󰁽󰁾󰁿󰂀󰂁󰂂󰁹", int($battery / 9), 1)
    }')"
  fi

  # Write to the cache file.
  echo "$cpu_temp$cpu_load$battery" > $cache_file
done