rill/internal/config/config.go

package config

import (
	_ "embed"
	"errors"
	"fmt"
	"io/fs"
	"log/slog"
	"net"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/goccy/go-yaml"
)

//go:embed config.default.yaml
var defaultConfigYAML []byte

type Config struct {
	Version  int            `yaml:"version"`
	Server   ServerConfig   `yaml:"server"`
	Log      LogConfig      `yaml:"log"`
	Static   StaticConfig   `yaml:"static"`
	Storage  StorageConfig  `yaml:"storage"`
	API      APIConfig      `yaml:"api"`
	Auth     AuthConfig     `yaml:"auth"`
	Database DatabaseConfig `yaml:"database"`
}

type ServerConfig struct {
	Host           string   `yaml:"host"`
	Port           int      `yaml:"port"`
	Sock           string   `yaml:"sock"`
	Mode           string   `yaml:"mode"`
	TrustedProxies []string `yaml:"trusted_proxies"`
}

// TCPEnabled 是否启用 TCP 监听（port 为 0 表示不启用）。
func (s ServerConfig) TCPEnabled() bool {
	return s.Port > 0
}

// SockEnabled 是否启用 unix socket 监听（sock 留空表示不启用）。
func (s ServerConfig) SockEnabled() bool {
	return strings.TrimSpace(s.Sock) != ""
}

type LogConfig struct {
	Level     string `yaml:"level"`
	AccessLog bool   `yaml:"access_log"`
}

type StaticConfig struct {
	Dir string `yaml:"dir"`
}

// StorageConfig 上传文件存储配置。
type StorageConfig struct {
	Dir       string `yaml:"dir"`         // 存储根目录
	MaxSizeMB int    `yaml:"max_size_mb"` // 单文件大小上限（MB）
}

// MaxUploadBytes 单文件大小上限（字节）。
func (c *Config) MaxUploadBytes() int64 {
	return int64(c.Storage.MaxSizeMB) << 20
}

type APIConfig struct {
	Prefix string     `yaml:"prefix"`
	CORS   CORSConfig `yaml:"cors"`
}

type CORSConfig struct {
	Enabled          bool     `yaml:"enabled"`
	AllowOrigins     []string `yaml:"allow_origins"`
	AllowMethods     []string `yaml:"allow_methods"`
	AllowHeaders     []string `yaml:"allow_headers"`
	AllowCredentials bool     `yaml:"allow_credentials"`
	MaxAge           string   `yaml:"max_age"`
}

type AuthConfig struct {
	Secret   string `yaml:"secret"`
	TokenTTL string `yaml:"token_ttl"`
}

type DatabaseConfig struct {
	Driver         string       `yaml:"driver"`          // sqlite3 / mysql
	ConnectTimeout string       `yaml:"connect_timeout"` // 建立连接超时
	SQLite         SQLiteConfig `yaml:"sqlite"`
	MySQL          MySQLConfig  `yaml:"mysql"`
}

type SQLiteConfig struct {
	Path string `yaml:"path"`
}

type MySQLConfig struct {
	Host            string `yaml:"host"`
	Port            int    `yaml:"port"`
	User            string `yaml:"user"`
	Password        string `yaml:"password"`
	Database        string `yaml:"database"`
	Charset         string `yaml:"charset"`
	MaxOpenConns    int    `yaml:"max_open_conns"`
	MaxIdleConns    int    `yaml:"max_idle_conns"`
	ConnMaxLifetime string `yaml:"conn_max_lifetime"`
}

func defaultConfig() *Config {
	return &Config{
		Server: ServerConfig{
			Host:           "0.0.0.0",
			Port:           8080,
			Sock:           "web.sock",
			Mode:           "release",
			TrustedProxies: []string{},
		},
		Log: LogConfig{
			Level:     "info",
			AccessLog: true,
		},
		Static: StaticConfig{
			Dir: "./dist",
		},
		Storage: StorageConfig{
			Dir:       "./data/uploads",
			MaxSizeMB: 10,
		},
		API: APIConfig{
			Prefix: "/api",
			CORS: CORSConfig{
				Enabled:          true,
				AllowOrigins:     []string{"http://localhost:5173"},
				AllowMethods:     []string{"GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"},
				AllowHeaders:     []string{"Origin", "Content-Type", "Accept", "Authorization"},
				AllowCredentials: false,
				MaxAge:           "12h",
			},
		},
		Auth: AuthConfig{
			TokenTTL: "24h",
		},
		Database: DatabaseConfig{
			Driver:         "sqlite3",
			ConnectTimeout: "10s",
			SQLite: SQLiteConfig{
				Path: "./data/rill.db",
			},
			MySQL: MySQLConfig{
				Host:            "127.0.0.1",
				Port:            3306,
				User:            "root",
				Password:        "",
				Database:        "rill",
				Charset:         "utf8mb4",
				MaxOpenConns:    10,
				MaxIdleConns:    5,
				ConnMaxLifetime: "1h",
			},
		},
	}
}

// LoadConfig 读取 YAML 配置文件，未指定的配置项使用默认值；文件不存在时自动生成默认配置文件。
func LoadConfig(path string) (*Config, error) {
	cfg := defaultConfig()

	data, err := os.ReadFile(path)
	switch {
	case err == nil:
		data = applyConfigUpgrade(path, data)
	case errors.Is(err, fs.ErrNotExist):
		if err := generateConfig(path); err != nil {
			return nil, err
		}
		data = defaultConfigYAML
	default:
		return nil, fmt.Errorf("读取配置文件 %s 失败: %w", path, err)
	}

	if err := yaml.Unmarshal(data, cfg); err != nil {
		return nil, fmt.Errorf("解析配置文件 %s 失败: %w", path, err)
	}

	if err := cfg.validate(); err != nil {
		return nil, err
	}
	return cfg, nil
}

func generateConfig(path string) error {
	if dir := filepath.Dir(path); dir != "." {
		if err := os.MkdirAll(dir, 0o755); err != nil {
			return fmt.Errorf("创建配置目录 %s 失败: %w", dir, err)
		}
	}
	if err := os.WriteFile(path, defaultConfigYAML, 0o644); err != nil {
		return fmt.Errorf("生成默认配置文件 %s 失败: %w", path, err)
	}
	slog.Info("配置文件不存在，已生成默认配置", "path", path)
	return nil
}

func (c *Config) validate() error {
	switch c.Server.Mode {
	case "debug", "release", "test":
	default:
		return fmt.Errorf("server.mode 无效: %q（可选: debug/release/test）", c.Server.Mode)
	}
	if c.Server.Port < 0 || c.Server.Port > 65535 {
		return fmt.Errorf("server.port 无效: %d（0 表示不启用 TCP）", c.Server.Port)
	}
	if !c.Server.TCPEnabled() && !c.Server.SockEnabled() {
		return fmt.Errorf("server.port 与 server.sock 至少需要启用一个")
	}
	for _, proxy := range c.Server.TrustedProxies {
		value := strings.TrimSpace(proxy)
		if value == "" || net.ParseIP(value) != nil {
			continue
		}
		if _, _, err := net.ParseCIDR(value); err != nil {
			return fmt.Errorf("server.trusted_proxies 无效: %q（需为 IP 或 CIDR）", proxy)
		}
	}
	if _, err := parseLogLevel(c.Log.Level); err != nil {
		return err
	}
	if _, err := time.ParseDuration(c.API.CORS.MaxAge); err != nil {
		return fmt.Errorf("api.cors.max_age 无效: %w", err)
	}
	if _, err := time.ParseDuration(c.Auth.TokenTTL); err != nil {
		return fmt.Errorf("auth.token_ttl 无效: %w", err)
	}
	if err := c.validateStorage(); err != nil {
		return err
	}
	if err := c.validateDatabase(); err != nil {
		return err
	}
	return nil
}

func (c *Config) validateStorage() error {
	if strings.TrimSpace(c.Storage.Dir) == "" {
		return fmt.Errorf("storage.dir 不能为空")
	}
	if c.Storage.MaxSizeMB < 1 || c.Storage.MaxSizeMB > 1024 {
		return fmt.Errorf("storage.max_size_mb 无效: %d（可选范围: 1-1024）", c.Storage.MaxSizeMB)
	}
	return nil
}

func (c *Config) validateDatabase() error {
	if _, err := time.ParseDuration(c.Database.ConnectTimeout); err != nil {
		return fmt.Errorf("database.connect_timeout 无效: %w", err)
	}

	switch c.Database.Driver {
	case "sqlite3":
		if strings.TrimSpace(c.Database.SQLite.Path) == "" {
			return fmt.Errorf("database.sqlite.path 不能为空")
		}
	case "mysql":
		db := c.Database.MySQL
		if strings.TrimSpace(db.Host) == "" {
			return fmt.Errorf("database.mysql.host 不能为空")
		}
		if db.Port <= 0 || db.Port > 65535 {
			return fmt.Errorf("database.mysql.port 无效: %d", db.Port)
		}
		if strings.TrimSpace(db.Database) == "" {
			return fmt.Errorf("database.mysql.database 不能为空")
		}
		if db.MaxOpenConns < 0 || db.MaxIdleConns < 0 {
			return fmt.Errorf("database.mysql 连接池大小不能为负数")
		}
		if _, err := time.ParseDuration(db.ConnMaxLifetime); err != nil {
			return fmt.Errorf("database.mysql.conn_max_lifetime 无效: %w", err)
		}
	default:
		return fmt.Errorf("database.driver 无效: %q（可选: sqlite3/mysql）", c.Database.Driver)
	}
	return nil
}

func (c *Config) LogLevel() slog.Level {
	level, _ := parseLogLevel(c.Log.Level)
	return level
}

func (c *Config) CORSMaxAge() time.Duration {
	maxAge, _ := time.ParseDuration(c.API.CORS.MaxAge)
	return maxAge
}

// TokenTTLDuration 登录凭证有效期，配置无效时返回 0。
func (c *Config) TokenTTLDuration() time.Duration {
	ttl, _ := time.ParseDuration(c.Auth.TokenTTL)
	return ttl
}

func parseLogLevel(level string) (slog.Level, error) {
	switch level {
	case "debug":
		return slog.LevelDebug, nil
	case "info":
		return slog.LevelInfo, nil
	case "warn":
		return slog.LevelWarn, nil
	case "error":
		return slog.LevelError, nil
	default:
		return slog.LevelInfo, fmt.Errorf("log.level 无效: %q（可选: debug/info/warn/error）", level)
	}
}