#!/bin/bash
# Emits {"temp":<celsius>} (or {"temp":null} if unavailable/disabled).
set -uo pipefail

ZONE="auto"
while (($# > 0)); do
    case "$1" in
    --zone)
        ZONE="${2:-auto}"
        shift 2
        ;;
    *) shift ;;
    esac
done

temp_c="null"
temp_path=""
if [[ "$ZONE" != "none" ]]; then
    if [[ -n "$ZONE" && "$ZONE" != "auto" && -r "$ZONE" ]]; then
        temp_path="$ZONE"
    else
        # Prefer a zone whose type identifies it as the CPU package/core sensor.
        # Falling back to "whichever zone reads hottest" can pick a GPU, NVMe,
        # or wifi zone on machines where those run hotter than the CPU.
        best=-1
        cpu_path=""
        for zone in /sys/class/thermal/thermal_zone*/temp; do
            [[ -r "$zone" ]] || continue
            v=$(<"$zone")
            [[ "$v" =~ ^[0-9]+$ ]] || continue
            if ((v > best)); then
                best=$v
                temp_path="$zone"
            fi
            if [[ -z "$cpu_path" ]]; then
                ztype=""
                [[ -r "${zone%/temp}/type" ]] && ztype=$(<"${zone%/temp}/type")
                [[ "$ztype" =~ ^(x86_pkg_temp|coretemp|k10temp|cpu_thermal|cpu-thermal)$ ]] && cpu_path="$zone"
            fi
        done
        [[ -n "$cpu_path" ]] && temp_path="$cpu_path"
    fi
    if [[ -n "$temp_path" && -r "$temp_path" ]]; then
        raw=$(<"$temp_path")
        if [[ "$raw" =~ ^[0-9]+$ ]]; then
            temp_c=$(awk -v r="$raw" 'BEGIN { printf "%.0f", r/1000 }')
        fi
    fi
fi

printf '{"temp":%s}\n' "$temp_c"