package drivers

import (
	"finally-a-monolithic-linux-hw-monitor/app/common"
	"fmt"
	"os"
	"path/filepath"
	"strconv"
	"strings"
)

const milliCperC = 1000.0

type HwmonDriver struct {
	hwmonDir    string
	hwmonDriver string
}

func NewHwmonDriver(expectedDrivers []string) (*HwmonDriver, error) {
	// Locate hwmon path
	dirs, err := filepath.Glob("/sys/class/hwmon/hwmon*")
	if err != nil {
		return nil, err
	}

	for _, dir := range dirs {
		nameRaw, err := os.ReadFile(filepath.Join(dir, "name"))
		name := strings.TrimSpace(string(nameRaw))
		if err == nil {
			for _, driver := range expectedDrivers {
				if driver == name {
					return &HwmonDriver{
						hwmonDir:    dir,
						hwmonDriver: driver,
					}, nil
				}
			}
		}
	}

	return nil, fmt.Errorf("could not find %#v in /sys/class/hwmon", expectedDrivers)
}

func (r *HwmonDriver) Render(term common.Terminal) error {
	t, err := r.Read()
	if err != nil {
		return err
	}

	temps := t.([]TemperatureSensor)
	term.Subheader("Temperature")

	for _, sensor := range temps {
		tempC := sensor.TempC
		tempF := (tempC * 9 / 5) + 32
		// \033[K clears from cursor to end of line (prevents lingering chars)
		term.Print(fmt.Sprintf("%-16s | %.2f °C (%.3f °F)", sensor.Name, tempC, tempF))
	}

	return nil
}

func (r *HwmonDriver) Read() (any, error) {
	inputs, err := filepath.Glob(filepath.Join(r.hwmonDir, "temp*_input"))
	if err != nil || len(inputs) == 0 {
		return nil, fmt.Errorf("no temperature inputs found in %s", r.hwmonDir)
	}

	temps := make([]TemperatureSensor, 0, len(inputs))

	for _, inputPath := range inputs {
		valBytes, err := os.ReadFile(inputPath)
		if err != nil {
			continue
		}

		milliC, err := strconv.ParseFloat(strings.TrimSpace(string(valBytes)), 64)
		if err != nil {
			continue
		}

		labelPath := strings.TrimSuffix(inputPath, "_input") + "_label"
		label := ""
		if lBytes, err := os.ReadFile(labelPath); err == nil {
			label = strings.TrimSpace(string(lBytes))
		} else {
			label = filepath.Base(strings.TrimSuffix(inputPath, "_input"))
		}

		temps = append(temps, TemperatureSensor{
			path:  inputPath,
			Name:  label,
			TempC: milliC / milliCperC,
		})
	}

	return temps, nil
}