package collect

import (
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
)

type Temp struct {
	Chip  string  `json:"chip"`
	Label string  `json:"label"`
	C     float64 `json:"c"`
}

// ReadTemps lists every hwmon temperature input; falls back to thermal zones.
func ReadTemps() []Temp {
	temps := readHwmon("/sys/class/hwmon")
	if len(temps) == 0 {
		temps = readThermalZones("/sys/class/thermal")
	}
	sort.Slice(temps, func(i, j int) bool {
		if temps[i].Chip != temps[j].Chip {
			return temps[i].Chip < temps[j].Chip
		}
		return temps[i].Label < temps[j].Label
	})
	return temps
}

func readHwmon(root string) []Temp {
	var out []Temp
	chips, _ := filepath.Glob(filepath.Join(root, "hwmon*"))
	for _, chip := range chips {
		name := readTrim(filepath.Join(chip, "name"))
		inputs, _ := filepath.Glob(filepath.Join(chip, "temp*_input"))
		for _, in := range inputs {
			v, err := strconv.ParseFloat(readTrim(in), 64)
			if err != nil {
				continue
			}
			base := strings.TrimSuffix(in, "_input")
			label := readTrim(base + "_label")
			if label == "" {
				label = filepath.Base(base)
			}
			out = append(out, Temp{Chip: name, Label: label, C: v / 1000})
		}
	}
	return out
}

func readThermalZones(root string) []Temp {
	var out []Temp
	zones, _ := filepath.Glob(filepath.Join(root, "thermal_zone*"))
	for _, z := range zones {
		v, err := strconv.ParseFloat(readTrim(filepath.Join(z, "temp")), 64)
		if err != nil {
			continue
		}
		out = append(out, Temp{Chip: "thermal", Label: readTrim(filepath.Join(z, "type")), C: v / 1000})
	}
	return out
}

// CPUTemp picks the most plausible CPU package temperature from the list.
func CPUTemp(temps []Temp) (float64, bool) {
	best, found := 0.0, false
	for _, t := range temps {
		chip := strings.ToLower(t.Chip)
		lbl := strings.ToLower(t.Label)
		isCPU := chip == "coretemp" || chip == "k10temp" || chip == "zenpower" ||
			strings.Contains(lbl, "package") || strings.Contains(lbl, "tctl") || strings.Contains(lbl, "tdie") ||
			strings.Contains(lbl, "x86_pkg_temp") || strings.Contains(lbl, "cpu")
		if isCPU && (!found || t.C > best) {
			best, found = t.C, true
		}
	}
	return best, found
}

func readTrim(p string) string {
	b, err := os.ReadFile(p)
	if err != nil {
		return ""
	}
	return strings.TrimSpace(string(b))
}