package main

import (
	"os"
	"path/filepath"
	"strconv"
)

// Config aggregates every runtime knob the sidecar reads from the
// environment. Held in one struct so the rest of the package can take a
// pointer instead of poking os.Getenv at use-sites.
type Config struct {
	OriginalsRoot     string // absolute path to PhotoPrism's originals dir
	PhotoprismBaseURL string // e.g. http://localhost:2342
	ListenAddr        string // bind interface — 127.0.0.1 for host mode, 0.0.0.0 in containers
	Port              int    // HTTP listen port
	DSN               string // GORM/MySQL connection string for mule_sidecar
	// PpDSN is a second DB connection string pointed at PhotoPrism's own
	// schema (`photoprism.*`). Sidecar code that needs to mutate
	// PhotoPrism-managed rows (e.g. auth_users.base_path) opens its own
	// connection with these creds rather than asking for grants on the
	// mule_sidecar user. Empty if PP_DB_PASSWORD isn't provided, in
	// which case PP-touching features (user-basepath reconciler) stay
	// dormant.
	PpDSN string
	// UserBasepaths is the parsed `USER_BASEPATHS` env. Maps PhotoPrism
	// usernames to originals-relative base paths so OIDC-provisioned
	// users land with the right library scope without any admin
	// touching `photoprism users mod`.
	UserBasepaths map[string]string
}

func loadConfig() (*Config, error) {
	root := envOr("ORIGINALS_ROOT", "/photoprism/originals")
	abs, err := filepath.Abs(root)
	if err != nil {
		return nil, err
	}

	portStr := envOr("SIDECAR_PORT", "8000")
	port, err := strconv.Atoi(portStr)
	if err != nil {
		return nil, err
	}

	dsn := os.Getenv("SIDECAR_DSN")
	if dsn == "" {
		// Default matches the user that mariadb/init/01-sidecar.sql provisions
		// on first boot. The literal placeholder password is intentional: the
		// SQL ships with it and an env-templating step is left for whoever
		// runs this in a non-local context.
		user := envOr("SIDECAR_DB_USER", "sidecar")
		pass := envOr("SIDECAR_DB_PASSWORD", "replace-at-m4-bringup")
		host := envOr("SIDECAR_DB_HOST", "127.0.0.1")
		dbPort := envOr("SIDECAR_DB_PORT", "3306")
		name := envOr("SIDECAR_DB_NAME", "mule_sidecar")
		dsn = user + ":" + pass + "@tcp(" + host + ":" + dbPort + ")/" + name +
			"?charset=utf8mb4&parseTime=true&loc=Local"
	}

	// PhotoPrism schema connection — only used by the user-basepath
	// reconciler. Stays empty if PP_DB_PASSWORD isn't set, and callers
	// gate behaviour on that. We use PhotoPrism's own DB user rather
	// than the sidecar's because `mule_sidecar` has no grants on
	// `photoprism.*` (see mariadb/init/01-sidecar.sql).
	ppDSN := ""
	if ppPass := os.Getenv("PP_DB_PASSWORD"); ppPass != "" {
		ppUser := envOr("PP_DB_USER", "photoprism")
		ppHost := envOr("PP_DB_HOST", envOr("SIDECAR_DB_HOST", "mariadb"))
		ppPort := envOr("PP_DB_PORT", envOr("SIDECAR_DB_PORT", "3306"))
		ppName := envOr("PP_DB_NAME", "photoprism")
		ppDSN = ppUser + ":" + ppPass + "@tcp(" + ppHost + ":" + ppPort + ")/" + ppName +
			"?charset=utf8mb4&parseTime=true&loc=Local"
	}

	return &Config{
		OriginalsRoot:     abs,
		PhotoprismBaseURL: envOr("PHOTOPRISM_BASE_URL", "http://localhost:2342"),
		ListenAddr:        envOr("SIDECAR_LISTEN_ADDR", "127.0.0.1"),
		Port:              port,
		DSN:               dsn,
		PpDSN:             ppDSN,
		UserBasepaths:     parseUserBasepaths(os.Getenv("USER_BASEPATHS")),
	}, nil
}

func envOr(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}