// Package settings owns this project's configuration; it adds no business identity model.
package settings

import (
	"errors"
	"fmt"
	"git.yuntuo.hk/k2safe/go-omni/config"
	"git.yuntuo.hk/k2safe/go-omni/database"
	"git.yuntuo.hk/k2safe/go-omni/logx"
	"git.yuntuo.hk/k2safe/go-omni/storage"
	"net/url"
	"os"
	"strconv"
	"strings"
	"time"
)

type Config struct {
	Server   config.Config   `json:"server"`
	Database database.Config `json:"database"`
	Storage  StorageConfig   `json:"storage"`
}

func Default() Config {
	server := config.Default()
	server.Address = "127.0.0.1:8080"
	server.EnableLogger = true
	server.SlowRequestThreshold = 500 * time.Millisecond
	server.Log.Service = "example.com/userService"
	server.Log.Format = "json"
	server.Log.File = "./var/log/server.log"
	server.Log.Rotation = logx.RotationConfig{Enabled: true, MaxSizeMB: 100, MaxBackups: 10, MaxAgeDays: 7, Compress: true}

	return Config{Server: server, Database: database.DefaultConfig(), Storage: StorageConfig{
		Provider: "local", Root: "./var/files", PublicURL: "http://127.0.0.1:8080/storage/object",
		Secure: true, MaxBytes: 32 << 20, ContentTypes: []string{"text/plain", "image/png", "image/jpeg", "application/pdf"},
		LinkTTL: 5 * time.Minute, RequestTimeout: 30 * time.Second,
	}}
}

// Load uses defaults -> strict YAML/JSON -> nonempty environment variables.
// Pass an empty path to use only defaults and environment.
func Load(path string) (Config, error) {
	cfg := Default()
	var err error
	if path != "" {
		cfg, err = config.DecodeFile(path, cfg)
		if err != nil {
			return Config{}, err
		}
	}
	cfg.Server, err = config.ApplyEnv(cfg.Server, "")
	if err != nil {
		return Config{}, err
	}
	// A stream explicitly selected by environment overrides a file profile.
	if output := strings.TrimSpace(os.Getenv("GO_OMNI_LOG_OUTPUT")); output != "" && strings.TrimSpace(os.Getenv("GO_OMNI_LOG_FILE")) == "" {
		cfg.Server.Log.File = ""
		cfg.Server.Log.Rotation = logx.RotationConfig{}
	}

	if err = cfg.Storage.applyEnv(); err != nil {
		return Config{}, err
	}

	cfg.Database, err = database.ApplyEnv(cfg.Database, "")
	if err != nil {
		return Config{}, err
	}
	if err = cfg.Validate(); err != nil {
		return Config{}, err
	}
	return cfg, nil
}
func (c Config) Validate() error {

	if err := c.Database.Validate(); err != nil {
		return err
	}
	if c.Database.Driver != "mysql" || c.Database.MaxOpenConns < 1 {
		return errors.New("database requires driver mysql and a positive maxOpenConns")
	}

	if err := c.Server.Validate(); err != nil {
		return err
	}
	if c.Server.Log.Format != "json" && c.Server.Log.Format != "text" {
		return errors.New("log.format must be json or text")
	}
	switch strings.ToLower(c.Server.Log.Level) {
	case "debug", "info", "warn", "warning", "error":
	default:
		return errors.New("invalid log.level")
	}
	return c.Storage.Validate()
}

type StorageConfig struct {
	Provider       string        `json:"provider"`
	Root           string        `json:"root"`
	PublicURL      string        `json:"publicUrl"`
	Endpoint       string        `json:"endpoint"`
	Region         string        `json:"region"`
	Bucket         string        `json:"bucket"`
	AccountID      string        `json:"accountId"`
	Secure         bool          `json:"secure"`
	MaxBytes       int64         `json:"maxBytes"`
	ContentTypes   []string      `json:"contentTypes"`
	LinkTTL        time.Duration `json:"linkTtl"`
	RequestTimeout time.Duration `json:"requestTimeout"`
	// Secrets are environment-only and cannot be populated by config files.
	FilesToken   string `json:"-"`
	SigningKey   string `json:"-"`
	AccessKey    string `json:"-"`
	SecretKey    string `json:"-"`
	SessionToken string `json:"-"`
}

func (s StorageConfig) Policy() storage.UploadPolicy {
	return storage.UploadPolicy{MaxBytes: s.MaxBytes, ContentTypes: s.ContentTypes}
}
func (s *StorageConfig) applyEnv() error {
	values := map[string]*string{
		"GO_OMNI_STORAGE_ROOT": &s.Root, "GO_OMNI_STORAGE_PUBLIC_URL": &s.PublicURL,
		"GO_OMNI_STORAGE_ENDPOINT": &s.Endpoint, "GO_OMNI_STORAGE_REGION": &s.Region,
		"GO_OMNI_STORAGE_BUCKET": &s.Bucket, "GO_OMNI_STORAGE_ACCOUNT_ID": &s.AccountID,
		"GO_OMNI_STORAGE_SIGNING_KEY": &s.SigningKey, "GO_OMNI_FILES_TOKEN": &s.FilesToken,
		"GO_OMNI_STORAGE_ACCESS_KEY": &s.AccessKey, "GO_OMNI_STORAGE_SECRET_KEY": &s.SecretKey,
		"GO_OMNI_STORAGE_SESSION_TOKEN": &s.SessionToken,
	}
	for name, target := range values {
		if value := strings.TrimSpace(os.Getenv(name)); value != "" {
			*target = value
		}
	}
	for name, target := range map[string]*time.Duration{"GO_OMNI_STORAGE_LINK_TTL": &s.LinkTTL, "GO_OMNI_STORAGE_REQUEST_TIMEOUT": &s.RequestTimeout} {
		if value := strings.TrimSpace(os.Getenv(name)); value != "" {
			v, err := time.ParseDuration(value)
			if err != nil {
				return fmt.Errorf("%s must be a duration", name)
			}
			*target = v
		}
	}
	if value := os.Getenv("GO_OMNI_STORAGE_MAX_BYTES"); value != "" {
		v, err := strconv.ParseInt(value, 10, 64)
		if err != nil {
			return errors.New("GO_OMNI_STORAGE_MAX_BYTES must be an integer")
		}
		s.MaxBytes = v
	}
	if value := os.Getenv("GO_OMNI_STORAGE_SECURE"); value != "" {
		v, err := strconv.ParseBool(value)
		if err != nil {
			return errors.New("GO_OMNI_STORAGE_SECURE must be a boolean")
		}
		s.Secure = v
	}
	if value := strings.TrimSpace(os.Getenv("GO_OMNI_STORAGE_CONTENT_TYPES")); value != "" {
		s.ContentTypes = strings.Split(value, ",")
		for i := range s.ContentTypes {
			s.ContentTypes[i] = strings.TrimSpace(s.ContentTypes[i])
		}
	}
	return nil
}
func (s StorageConfig) Validate() error {
	if s.Provider != "local" {
		return errors.New("storage.provider must match the adapter selected at generation")
	}
	if err := s.Policy().Validate(); err != nil {
		return err
	}
	if s.LinkTTL < time.Second || s.LinkTTL > time.Hour {
		return errors.New("storage.linkTtl must be 1s..1h")
	}
	if s.RequestTimeout <= 0 || s.RequestTimeout > 5*time.Minute {
		return errors.New("storage.requestTimeout must be >0 and <=5m")
	}

	if s.Root == "" {
		return errors.New("storage.root is required")
	}
	u, err := url.Parse(s.PublicURL)
	if err != nil || u.Host == "" || u.Hostname() == "" || (u.Scheme != "http" && u.Scheme != "https") || u.User != nil || u.RawQuery != "" || u.Fragment != "" || u.Path != "/storage/object" {
		return errors.New("storage.publicUrl must be an absolute HTTP(S) URL ending in /storage/object")
	}
	if len(s.SigningKey) < 32 {
		return errors.New("set GO_OMNI_STORAGE_SIGNING_KEY to a stable secret of at least 32 bytes")
	}

	return nil
}