1 files changed, 153 insertions, 0 deletions
diff --git a/internal/config/config.go b/internal/config/config.go
new file mode 100644
index 0000000..5e6e467
--- /dev/null
+++ b/internal/config/config.go
@@ -0,0 +1,153 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+
+	"gopkg.in/yaml.v3"
+)
+
+const (
+	ModeResolver = "resolver"
+	ModeMirror   = "mirror"
+
+	VerifyFull      = "full"
+	VerifyLazy      = "lazy"
+	VerifyStateOnly = "state-only"
+)
+
+type Config struct {
+	Mode                 string        `yaml:"mode"`
+	DataDir              string        `yaml:"data_dir"`
+	PLCSource            string        `yaml:"plc_source"`
+	VerifyPolicy         string        `yaml:"verify"`
+	ZstdLevel            int           `yaml:"zstd_level"`
+	BlockSizeMB          int           `yaml:"block_size_mb"`
+	CheckpointInterval   uint64        `yaml:"checkpoint_interval"`
+	CommitBatchSize      int           `yaml:"commit_batch_size"`
+	VerifyWorkers        int           `yaml:"verify_workers"`
+	ListenAddr           string        `yaml:"listen_addr"`
+	MirrorPrivateKeyPath string        `yaml:"mirror_private_key_path"`
+	PollInterval         time.Duration `yaml:"poll_interval"`
+}
+
+func Default() Config {
+	return Config{
+		Mode:                 ModeMirror,
+		DataDir:              "./data",
+		PLCSource:            "https://plc.directory",
+		VerifyPolicy:         VerifyFull,
+		ZstdLevel:            9,
+		BlockSizeMB:          8,
+		CheckpointInterval:   100000,
+		CommitBatchSize:      128,
+		VerifyWorkers:        runtime.NumCPU(),
+		ListenAddr:           ":8080",
+		MirrorPrivateKeyPath: "./mirror.key",
+		PollInterval:         5 * time.Second,
+	}
+}
+
+func Load(path string) (Config, error) {
+	cfg := Default()
+	if path != "" {
+		b, err := os.ReadFile(path)
+		if err != nil {
+			return Config{}, fmt.Errorf("read config: %w", err)
+		}
+		if err := yaml.Unmarshal(b, &cfg); err != nil {
+			return Config{}, fmt.Errorf("parse config: %w", err)
+		}
+	}
+	applyEnv(&cfg)
+	if err := cfg.Validate(); err != nil {
+		return Config{}, err
+	}
+	return cfg, nil
+}
+
+func applyEnv(cfg *Config) {
+	setString := func(key string, dst *string) {
+		if v := strings.TrimSpace(os.Getenv(key)); v != "" {
+			*dst = v
+		}
+	}
+	setInt := func(key string, dst *int) {
+		if v := strings.TrimSpace(os.Getenv(key)); v != "" {
+			if n, err := strconv.Atoi(v); err == nil {
+				*dst = n
+			}
+		}
+	}
+	setUint64 := func(key string, dst *uint64) {
+		if v := strings.TrimSpace(os.Getenv(key)); v != "" {
+			if n, err := strconv.ParseUint(v, 10, 64); err == nil {
+				*dst = n
+			}
+		}
+	}
+	setDuration := func(key string, dst *time.Duration) {
+		if v := strings.TrimSpace(os.Getenv(key)); v != "" {
+			if d, err := time.ParseDuration(v); err == nil {
+				*dst = d
+			}
+		}
+	}
+
+	setString("PLUTIA_MODE", &cfg.Mode)
+	setString("PLUTIA_DATA_DIR", &cfg.DataDir)
+	setString("PLUTIA_PLC_SOURCE", &cfg.PLCSource)
+	setString("PLUTIA_VERIFY", &cfg.VerifyPolicy)
+	setInt("PLUTIA_ZSTD_LEVEL", &cfg.ZstdLevel)
+	setInt("PLUTIA_BLOCK_SIZE_MB", &cfg.BlockSizeMB)
+	setInt("PLUTIA_COMMIT_BATCH_SIZE", &cfg.CommitBatchSize)
+	setInt("PLUTIA_VERIFY_WORKERS", &cfg.VerifyWorkers)
+	setUint64("PLUTIA_CHECKPOINT_INTERVAL", &cfg.CheckpointInterval)
+	setString("PLUTIA_LISTEN_ADDR", &cfg.ListenAddr)
+	setString("PLUTIA_MIRROR_PRIVATE_KEY_PATH", &cfg.MirrorPrivateKeyPath)
+	setDuration("PLUTIA_POLL_INTERVAL", &cfg.PollInterval)
+}
+
+func (c Config) Validate() error {
+	if c.Mode != ModeResolver && c.Mode != ModeMirror {
+		return fmt.Errorf("invalid mode %q", c.Mode)
+	}
+	switch c.VerifyPolicy {
+	case VerifyFull, VerifyLazy, VerifyStateOnly:
+	default:
+		return fmt.Errorf("invalid verify policy %q", c.VerifyPolicy)
+	}
+	if c.DataDir == "" {
+		return errors.New("data_dir is required")
+	}
+	if c.PLCSource == "" {
+		return errors.New("plc_source is required")
+	}
+	if c.ZstdLevel < 1 || c.ZstdLevel > 22 {
+		return fmt.Errorf("zstd_level must be between 1 and 22, got %d", c.ZstdLevel)
+	}
+	if c.BlockSizeMB < 4 || c.BlockSizeMB > 16 {
+		return fmt.Errorf("block_size_mb must be between 4 and 16, got %d", c.BlockSizeMB)
+	}
+	if c.CheckpointInterval == 0 {
+		return errors.New("checkpoint_interval must be > 0")
+	}
+	if c.CommitBatchSize <= 0 || c.CommitBatchSize > 4096 {
+		return fmt.Errorf("commit_batch_size must be between 1 and 4096, got %d", c.CommitBatchSize)
+	}
+	if c.VerifyWorkers <= 0 || c.VerifyWorkers > 1024 {
+		return fmt.Errorf("verify_workers must be between 1 and 1024, got %d", c.VerifyWorkers)
+	}
+	if c.ListenAddr == "" {
+		return errors.New("listen_addr is required")
+	}
+	if c.PollInterval <= 0 {
+		return errors.New("poll_interval must be > 0")
+	}
+	return nil
+}