3 files changed, 493 insertions, 0 deletions
diff --git a/cmd/apple-silicon-info/README.org b/cmd/apple-silicon-info/README.org
new file mode 100644
index 0000000..682a11c
--- /dev/null
+++ b/cmd/apple-silicon-info/README.org
@@ -0,0 +1,15 @@
+* socinfo
+
+A lightweight macOS utility that gathers detailed information about Apple Silicon System-on-Chip (SoC) specifications.
+
+** What it does
+
+=socinfo= queries your Mac's hardware through system utilities to retrieve:
+
+- CPU brand name and core configuration
+- GPU core count
+- Performance and efficiency core breakdown
+- Thermal Design Power (TDP) specifications
+- Memory bandwidth specifications
+
+The tool automatically detects your specific Apple Silicon variant (M1, M1 Pro/Max/Ultra, M2, M2 Pro/Max/Ultra, M3, M3 Pro/Max) and provides the corresponding technical specifications.
diff --git a/cmd/apple-silicon-info/main.go b/cmd/apple-silicon-info/main.go
new file mode 100644
index 0000000..f733d7e
--- /dev/null
+++ b/cmd/apple-silicon-info/main.go
@@ -0,0 +1,281 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+// Custom error types
+var (
+	ErrParse   = errors.New("socinfo parsing error")
+	ErrCommand = errors.New("command execution error")
+	ErrConvert = errors.New("conversion error")
+)
+
+type (
+	Watts     = uint32
+	Bandwidth = uint32
+	CoreCount = uint16
+)
+
+// SocInfo represents information about the Silicon chip
+type SocInfo struct {
+	CPUBrandName string     `json:"cpu_brand_name"`
+	NumCPUCores  CoreCount  `json:"num_cpu_cores"`
+	NumGPUCores  CoreCount  `json:"num_gpu_cores"`
+	CPUMaxPower  *Watts     `json:"cpu_max_power,omitempty"`
+	GPUMaxPower  *Watts     `json:"gpu_max_power,omitempty"`
+	CPUMaxBW     *Bandwidth `json:"cpu_max_bw,omitempty"`
+	GPUMaxBW     *Bandwidth `json:"gpu_max_bw,omitempty"`
+	ECoreCount   CoreCount  `json:"e_core_count"`
+	PCoreCount   CoreCount  `json:"p_core_count"`
+}
+
+// AppleChip represents different Apple Silicon variants
+type AppleChip int
+
+const (
+	M1 AppleChip = iota
+	M1Pro
+	M1Max
+	M1Ultra
+	M2
+	M2Pro
+	M2Max
+	M2Ultra
+	M3
+	M3Pro
+	M3Max
+	Unknown
+)
+
+// ChipSpecs holds the specifications for each chip variant
+type ChipSpecs struct {
+	CPUTDP Watts
+	GPUTDP Watts
+	CPUBW  Bandwidth
+	GPUBW  Bandwidth
+}
+
+// fromBrandString determines the Apple chip type from brand string
+func fromBrandString(brand string) AppleChip {
+	switch {
+	case strings.Contains(brand, "M1 Pro"):
+		return M1Pro
+	case strings.Contains(brand, "M1 Max"):
+		return M1Max
+	case strings.Contains(brand, "M1 Ultra"):
+		return M1Ultra
+	case strings.Contains(brand, "M1"):
+		return M1
+	case strings.Contains(brand, "M2 Pro"):
+		return M2Pro
+	case strings.Contains(brand, "M2 Max"):
+		return M2Max
+	case strings.Contains(brand, "M2 Ultra"):
+		return M2Ultra
+	case strings.Contains(brand, "M2"):
+		return M2
+	case strings.Contains(brand, "M3 Pro"):
+		return M3Pro
+	case strings.Contains(brand, "M3 Max"):
+		return M3Max
+	case strings.Contains(brand, "M3"):
+		return M3
+	default:
+		return Unknown
+	}
+}
+
+// getSpecs returns the specifications for the chip
+func (chip AppleChip) getSpecs() ChipSpecs {
+	switch chip {
+	case M1:
+		return ChipSpecs{CPUTDP: 20, GPUTDP: 20, CPUBW: 70, GPUBW: 70}
+	case M1Pro:
+		return ChipSpecs{CPUTDP: 30, GPUTDP: 30, CPUBW: 200, GPUBW: 200}
+	case M1Max:
+		return ChipSpecs{CPUTDP: 30, GPUTDP: 60, CPUBW: 250, GPUBW: 400}
+	case M1Ultra:
+		return ChipSpecs{CPUTDP: 60, GPUTDP: 120, CPUBW: 500, GPUBW: 800}
+	case M2:
+		return ChipSpecs{CPUTDP: 25, GPUTDP: 15, CPUBW: 100, GPUBW: 100}
+	case M2Pro:
+		return ChipSpecs{CPUTDP: 30, GPUTDP: 35, CPUBW: 0, GPUBW: 0}
+	case M2Max:
+		return ChipSpecs{CPUTDP: 30, GPUTDP: 40, CPUBW: 0, GPUBW: 0}
+	default:
+		return ChipSpecs{CPUTDP: 0, GPUTDP: 0, CPUBW: 0, GPUBW: 0}
+	}
+}
+
+// SystemCommand interface for testable command execution
+type SystemCommand interface {
+	Execute(binary string, args ...string) ([]byte, error)
+}
+
+// RealCommand implements SystemCommand for actual system calls
+type RealCommand struct{}
+
+func (r *RealCommand) Execute(binary string, args ...string) ([]byte, error) {
+	cmd := exec.Command(binary, args...)
+	output, err := cmd.Output()
+	if err != nil {
+		return nil, fmt.Errorf("%w: %v", ErrCommand, err)
+	}
+	return output, nil
+}
+
+const sysctlPath = "/usr/sbin/sysctl"
+
+// getCPUInfo retrieves CPU information using sysctl
+func getCPUInfo(cmd SystemCommand) (string, CoreCount, CoreCount, CoreCount, error) {
+	args := []string{
+		"-n", // don't display the variable name
+		"machdep.cpu.brand_string",
+		"machdep.cpu.core_count",
+		"hw.perflevel0.logicalcpu",
+		"hw.perflevel1.logicalcpu",
+	}
+
+	output, err := cmd.Execute(sysctlPath, args...)
+	if err != nil {
+		return "", 0, 0, 0, err
+	}
+
+	lines := strings.Split(strings.TrimSpace(string(output)), "\n")
+	if len(lines) < 4 {
+		return "", 0, 0, 0, fmt.Errorf("%w: insufficient output lines", ErrParse)
+	}
+
+	cpuBrandName := lines[0]
+
+	numCPUCores, err := strconv.ParseUint(lines[1], 10, 16)
+	if err != nil {
+		return "", 0, 0, 0, fmt.Errorf("%w: parsing cpu cores: %v", ErrConvert, err)
+	}
+
+	numPerformanceCores, err := strconv.ParseUint(lines[2], 10, 16)
+	if err != nil {
+		return "", 0, 0, 0, fmt.Errorf("%w: parsing performance cores: %v", ErrConvert, err)
+	}
+
+	numEfficiencyCores, err := strconv.ParseUint(lines[3], 10, 16)
+	if err != nil {
+		return "", 0, 0, 0, fmt.Errorf("%w: parsing efficiency cores: %v", ErrConvert, err)
+	}
+
+	return cpuBrandName, CoreCount(
+			numCPUCores,
+		), CoreCount(
+			numPerformanceCores,
+		), CoreCount(
+			numEfficiencyCores,
+		), nil
+}
+
+// getGPUInfo retrieves GPU information using system_profiler
+func getGPUInfo(cmd SystemCommand) (CoreCount, error) {
+	args := []string{"-detailLevel", "basic", "SPDisplaysDataType"}
+
+	output, err := cmd.Execute("/usr/sbin/system_profiler", args...)
+	if err != nil {
+		return 0, err
+	}
+
+	scanner := bufio.NewScanner(strings.NewReader(string(output)))
+	for scanner.Scan() {
+		line := scanner.Text()
+		trimmed := strings.TrimSpace(line)
+		if strings.HasPrefix(trimmed, "Total Number of Cores") {
+			parts := strings.Split(trimmed, ": ")
+			if len(parts) == 2 {
+				cores, err := strconv.ParseUint(strings.TrimSpace(parts[1]), 10, 16)
+				if err != nil {
+					return 0, fmt.Errorf("%w: parsing gpu cores: %v", ErrConvert, err)
+				}
+				return CoreCount(cores), nil
+			}
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return 0, fmt.Errorf("%w: scanning output: %v", ErrParse, err)
+	}
+
+	return 0, fmt.Errorf("%w: GPU core count not found", ErrParse)
+}
+
+// NewSocInfo creates a new SocInfo instance by gathering system information
+func NewSocInfo() (*SocInfo, error) {
+	cmd := &RealCommand{}
+	return NewSocInfoWithCommand(cmd)
+}
+
+// NewSocInfoWithCommand creates a new SocInfo instance with a custom command executor (for testing)
+func NewSocInfoWithCommand(cmd SystemCommand) (*SocInfo, error) {
+	cpuBrandName, numCPUCores, eCoreCount, pCoreCount, err := getCPUInfo(cmd)
+	if err != nil {
+		return nil, err
+	}
+
+	numGPUCores, err := getGPUInfo(cmd)
+	if err != nil {
+		return nil, err
+	}
+
+	chip := fromBrandString(cpuBrandName)
+	specs := chip.getSpecs()
+
+	var cpuMaxPower, gpuMaxPower *Watts
+	var cpuMaxBW, gpuMaxBW *Bandwidth
+
+	if specs.CPUTDP > 0 {
+		cpuMaxPower = &specs.CPUTDP
+	}
+	if specs.GPUTDP > 0 {
+		gpuMaxPower = &specs.GPUTDP
+	}
+	if specs.CPUBW > 0 {
+		cpuMaxBW = &specs.CPUBW
+	}
+	if specs.GPUBW > 0 {
+		gpuMaxBW = &specs.GPUBW
+	}
+
+	return &SocInfo{
+		CPUBrandName: cpuBrandName,
+		NumCPUCores:  numCPUCores,
+		NumGPUCores:  numGPUCores,
+		CPUMaxPower:  cpuMaxPower,
+		GPUMaxPower:  gpuMaxPower,
+		CPUMaxBW:     cpuMaxBW,
+		GPUMaxBW:     gpuMaxBW,
+		ECoreCount:   eCoreCount,
+		PCoreCount:   pCoreCount,
+	}, nil
+}
+
+func main() {
+	socInfo, err := NewSocInfo()
+	if err != nil {
+		fmt.Printf("Error getting SoC info: %v\n", err)
+		return
+	}
+
+	var cpuPower Watts
+	if socInfo.CPUMaxPower != nil {
+		cpuPower = *socInfo.CPUMaxPower
+	}
+
+	fmt.Printf("Our CPU is an %s, and we have %d CPU cores, and %d GPU cores. The TDP is %d.\n",
+		socInfo.CPUBrandName,
+		socInfo.NumCPUCores,
+		socInfo.NumGPUCores,
+		cpuPower,
+	)
+}
diff --git a/cmd/apple-silicon-info/main_test.go b/cmd/apple-silicon-info/main_test.go
new file mode 100644
index 0000000..a9b7caf
--- /dev/null
+++ b/cmd/apple-silicon-info/main_test.go
@@ -0,0 +1,197 @@
+package main
+
+import (
+	"errors"
+	"testing"
+)
+
+type MockCommand struct {
+	output string
+	err    error
+}
+
+func NewMockCommand(output string) *MockCommand {
+	return &MockCommand{output: output}
+}
+
+func NewMockCommandWithError(err error) *MockCommand {
+	return &MockCommand{err: err}
+}
+
+func (m *MockCommand) Execute(binary string, args ...string) ([]byte, error) {
+	if m.err != nil {
+		return nil, m.err
+	}
+	return []byte(m.output), nil
+}
+
+func TestGetGPUInfo(t *testing.T) {
+	mockOutput := `Graphics/Displays:
+            Apple M2:
+              Total Number of Cores: 10`
+
+	cmd := NewMockCommand(mockOutput)
+
+	result, err := getGPUInfo(cmd)
+	if err != nil {
+		t.Fatalf("Expected no error, got: %v", err)
+	}
+
+	expected := CoreCount(10)
+	if result != expected {
+		t.Errorf("Expected %d GPU cores, got %d", expected, result)
+	}
+}
+
+func TestGetGPUInfoNotFound(t *testing.T) {
+	mockOutput := `Graphics/Displays:
+            Apple M2:
+              Some other field: 10`
+
+	cmd := NewMockCommand(mockOutput)
+
+	_, err := getGPUInfo(cmd)
+	if err == nil {
+		t.Fatal("Expected error when GPU cores not found, got nil")
+	}
+}
+
+func TestGetCPUInfoSuccess(t *testing.T) {
+	mockOutput := "Apple M2\n8\n4\n4\n"
+	cmd := NewMockCommand(mockOutput)
+
+	brand, cores, pCores, eCores, err := getCPUInfo(cmd)
+	if err != nil {
+		t.Fatalf("Expected no error, got: %v", err)
+	}
+
+	if brand != "Apple M2" {
+		t.Errorf("Expected brand 'Apple M2', got '%s'", brand)
+	}
+	if cores != 8 {
+		t.Errorf("Expected 8 cores, got %d", cores)
+	}
+	if pCores != 4 {
+		t.Errorf("Expected 4 performance cores, got %d", pCores)
+	}
+	if eCores != 4 {
+		t.Errorf("Expected 4 efficiency cores, got %d", eCores)
+	}
+}
+
+func TestGetCPUInfoMissingCoreCount(t *testing.T) {
+	mockOutput := "Apple M2\n"
+	cmd := NewMockCommand(mockOutput)
+
+	_, _, _, _, err := getCPUInfo(cmd)
+	if err == nil {
+		t.Fatal("Expected error with insufficient output, got nil")
+	}
+}
+
+func TestGetCPUInfoInvalidCoreCount(t *testing.T) {
+	mockOutput := "Apple M2\ninvalid\n4\n4\n"
+	cmd := NewMockCommand(mockOutput)
+
+	_, _, _, _, err := getCPUInfo(cmd)
+	if err == nil {
+		t.Fatal("Expected error with invalid core count, got nil")
+	}
+}
+
+func TestFromBrandString(t *testing.T) {
+	tests := []struct {
+		brand    string
+		expected AppleChip
+	}{
+		{"Apple M1", M1},
+		{"Apple M1 Pro", M1Pro},
+		{"Apple M1 Max", M1Max},
+		{"Apple M1 Ultra", M1Ultra},
+		{"Apple M2", M2},
+		{"Apple M2 Pro", M2Pro},
+		{"Apple M2 Max", M2Max},
+		{"Apple M2 Ultra", M2Ultra},
+		{"Apple M3", M3},
+		{"Apple M3 Pro", M3Pro},
+		{"Apple M3 Max", M3Max},
+		{"Intel Core i7", Unknown},
+	}
+
+	for _, test := range tests {
+		result := fromBrandString(test.brand)
+		if result != test.expected {
+			t.Errorf("For brand '%s', expected %v, got %v", test.brand, test.expected, result)
+		}
+	}
+}
+
+func TestChipGetSpecs(t *testing.T) {
+	tests := []struct {
+		chip     AppleChip
+		expected ChipSpecs
+	}{
+		{M1, ChipSpecs{CPUTDP: 20, GPUTDP: 20, CPUBW: 70, GPUBW: 70}},
+		{M1Pro, ChipSpecs{CPUTDP: 30, GPUTDP: 30, CPUBW: 200, GPUBW: 200}},
+		{M2, ChipSpecs{CPUTDP: 25, GPUTDP: 15, CPUBW: 100, GPUBW: 100}},
+		{Unknown, ChipSpecs{CPUTDP: 0, GPUTDP: 0, CPUBW: 0, GPUBW: 0}},
+	}
+
+	for _, test := range tests {
+		result := test.chip.getSpecs()
+		if result != test.expected {
+			t.Errorf("For chip %v, expected %+v, got %+v", test.chip, test.expected, result)
+		}
+	}
+}
+
+func TestNewSocInfoWithCommand(t *testing.T) {
+	sysctlOutput := "Apple M2\n8\n4\n4\n"
+
+	profilerOutput := `Graphics/Displays:
+            Apple M2:
+              Total Number of Cores: 10`
+
+	cmd := &MockCommandMultiple{
+		outputs: map[string]string{
+			"/usr/sbin/sysctl":          sysctlOutput,
+			"/usr/sbin/system_profiler": profilerOutput,
+		},
+	}
+
+	socInfo, err := NewSocInfoWithCommand(cmd)
+	if err != nil {
+		t.Fatalf("Expected no error, got: %v", err)
+	}
+
+	if socInfo.CPUBrandName != "Apple M2" {
+		t.Errorf("Expected CPU brand 'Apple M2', got '%s'", socInfo.CPUBrandName)
+	}
+	if socInfo.NumCPUCores != 8 {
+		t.Errorf("Expected 8 CPU cores, got %d", socInfo.NumCPUCores)
+	}
+	if socInfo.NumGPUCores != 10 {
+		t.Errorf("Expected 10 GPU cores, got %d", socInfo.NumGPUCores)
+	}
+	if socInfo.CPUMaxPower == nil || *socInfo.CPUMaxPower != 25 {
+		t.Errorf("Expected CPU max power 25W, got %v", socInfo.CPUMaxPower)
+	}
+}
+
+type MockCommandMultiple struct {
+	outputs map[string]string
+	err     error
+}
+
+func (m *MockCommandMultiple) Execute(binary string, args ...string) ([]byte, error) {
+	if m.err != nil {
+		return nil, m.err
+	}
+
+	output, exists := m.outputs[binary]
+	if !exists {
+		return nil, errors.New("binary not found in mock")
+	}
+
+	return []byte(output), nil
+}