package drivers

import (
	"bufio"
	"fmt"
	"os/exec"
	"strconv"
	"strings"
)

type DmiDecodeDriver struct{}

func NewDmiDecodeDriver() (*DmiDecodeDriver, error) {
	r := DmiDecodeDriver{}
	_, err := r.Read()
	return &r, err
}

func (r *DmiDecodeDriver) Render(console *strings.Builder) error {
	h, err := r.Read()
	if err != nil {
		return err
	}

	hardware := h.(MemoryHardware)

	for i := range len(hardware.ModelNames) {
		fmt.Fprintf(console, "--- RAM Module %d ---\n", i)
		modelName := hardware.ModelNames[i]
		fmt.Fprintf(console, "%-16s | %-16s \033[K\n", "Model Name", modelName)
		generation := hardware.Generations[i]
		speed := hardware.Speeds[i]
		fmt.Fprintf(console, "%-16s | %s@%s \033[K\n", "Speed", generation, speed)
		formFactor := hardware.FormFactors[i]
		fmt.Fprintf(console, "%-16s | %s \033[K\n", "Form Factor", formFactor)
	}

	return nil
}

// Parses dmidecode to extract physical hardware limits, slot counts, and module details
func (r *DmiDecodeDriver) Read() (any, error) {
	hw := MemoryHardware{}

	// Query Memory Array (Type 16) for Max Capacity and Slot Count
	arrayCmd := exec.Command("dmidecode", "-t", "16")
	arrayOutput, err := arrayCmd.Output()
	if err != nil {
		return hw, fmt.Errorf("dmidecode -t 16 failed: %w", err)
	}

	// Query Memory Device (Type 17) for active slots, speed, type, form factor, and model name
	deviceCmd := exec.Command("dmidecode", "-t", "17")
	deviceOutput, err := deviceCmd.Output()
	if err != nil {
		return hw, fmt.Errorf("dmidecode -t 17 failed: %w", err)
	}

	// Parse Type 16 Output
	scanner := bufio.NewScanner(strings.NewReader(string(arrayOutput)))
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if strings.HasPrefix(line, "Maximum Capacity:") {
			hw.MaxCapacityGB = parseCapacityToGB(line)
		} else if strings.HasPrefix(line, "Number Of Devices:") {
			parts := strings.Split(line, ":")
			if len(parts) == 2 {
				hw.TotalSlots, _ = strconv.Atoi(strings.TrimSpace(parts[1]))
			} else {
				return hw, fmt.Errorf("parsing dmidecode -t 16 failed")
			}
		}
	}

	// Parse Type 17 Output
	var currentSize, currentType, currentSpeed, currentForm, currentVendor, currentPart string

	deviceScanner := bufio.NewScanner(strings.NewReader(string(deviceOutput)))
	for deviceScanner.Scan() {
		line := strings.TrimSpace(deviceScanner.Text())

		if strings.HasPrefix(line, "Memory Device") {
			processDeviceBlock(currentSize, currentType, currentSpeed, currentForm, currentVendor, currentPart, &hw)
			currentSize, currentType, currentSpeed, currentForm, currentVendor, currentPart = "", "", "", "", "", ""
			continue
		}

		if strings.HasPrefix(line, "Size:") {
			currentSize = strings.TrimSpace(strings.TrimPrefix(line, "Size:"))
		} else if strings.HasPrefix(line, "Type:") {
			currentType = strings.TrimSpace(strings.TrimPrefix(line, "Type:"))
		} else if strings.HasPrefix(line, "Speed:") || strings.HasPrefix(line, "Configured Memory Speed:") {
			val := strings.TrimSpace(strings.Split(line, ":")[1])
			if val != "Unknown" && val != "" && currentSpeed == "" {
				currentSpeed = val
			}
		} else if strings.HasPrefix(line, "Form Factor:") {
			currentForm = strings.TrimSpace(strings.TrimPrefix(line, "Form Factor:"))
		} else if strings.HasPrefix(line, "Manufacturer:") {
			currentVendor = strings.TrimSpace(strings.TrimPrefix(line, "Manufacturer:"))
		} else if strings.HasPrefix(line, "Part Number:") {
			currentPart = strings.TrimSpace(strings.TrimPrefix(line, "Part Number:"))
		}
	}
	// Process the final block
	processDeviceBlock(currentSize, currentType, currentSpeed, currentForm, currentVendor, currentPart, &hw)

	return hw, nil
}

func processDeviceBlock(size, memType, speed, form, vendor, part string, hw *MemoryHardware) {
	if size != "" && size != "No Module Installed" && size != "Unknown" {
		hw.SlotsUsed++

		if memType != "" && memType != "Unknown" {
			hw.Generations = append(hw.Generations, memType)
		} else {
			hw.Generations = append(hw.Generations, "Unknown")
		}

		if speed != "" && speed != "Unknown" {
			hw.Speeds = append(hw.Speeds, speed)
		} else {
			hw.Speeds = append(hw.Speeds, "Unknown")
		}

		if form != "" && form != "Unknown" {
			hw.FormFactors = append(hw.FormFactors, form)
		} else {
			hw.FormFactors = append(hw.FormFactors, "Unknown")
		}

		// Construct model/part identifier
		partClean := cleanString(part)
		vendorClean := cleanString(vendor)

		if partClean != "" && vendorClean != "" {
			hw.ModelNames = append(hw.ModelNames, fmt.Sprintf("%s (%s)", partClean, vendorClean))
		} else if partClean != "" {
			hw.ModelNames = append(hw.ModelNames, partClean)
		} else if vendorClean != "" {
			hw.ModelNames = append(hw.ModelNames, vendorClean)
		} else {
			hw.ModelNames = append(hw.ModelNames, "Unknown")
		}
	}
}

func cleanString(val string) string {
	v := strings.TrimSpace(val)
	if v == "" || v == "Unknown" || v == "NO DIMM" || strings.HasPrefix(v, "0x") {
		return ""
	}
	return v
}

func parseCapacityToGB(line string) float64 {
	parts := strings.Split(line, ":")
	if len(parts) < 2 {
		return 0
	}
	valStr := strings.TrimSpace(parts[1])
	fields := strings.Fields(valStr)
	if len(fields) < 2 {
		return 0
	}
	val, err := strconv.ParseFloat(fields[0], 64)
	if err != nil {
		return 0
	}
	unit := strings.ToUpper(fields[1])
	if strings.HasPrefix(unit, "TB") {
		return val * 1024
	} else if strings.HasPrefix(unit, "MB") {
		return val / 1024
	}
	return val
}

func formatSlice(s []string) string {
	if len(s) == 0 {
		return "N/A"
	}
	return strings.Join(s, ", ")
}