// Package config loads mediamark runtime configuration from the environment.
package config

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
)

// Config is the fully-resolved mediamark configuration.
type Config struct {
	// Listen is the HTTP listen address, e.g. ":8080".
	Listen string
	// MediaRoot holds the fafflix/ (source) and cheeztv/ (kids) library trees.
	MediaRoot string
	// KeysDir holds per-app *arr api keys as files named "sonarr"/"radarr",
	// projected by the Vault Secrets Operator and re-read on every use.
	KeysDir string
	// SonarrURL and RadarrURL include the *arr instance's UrlBase; the API
	// lives at <url>/api/v3/...
	SonarrURL string
	RadarrURL string
	// GroupsHeader is the oauth2-proxy header carrying Authentik group names.
	GroupsHeader string
	// AllowedGroups gates every page load and API call. Never empty.
	AllowedGroups []string
}

// Load resolves configuration from the environment, failing closed on an empty
// allow-list (an empty list would authorize nobody or, worse, be read as
// "anyone" by a future refactor).
func Load() (*Config, error) {
	c := &Config{
		Listen:        envOr("MEDIAMARK_LISTEN", ":8080"),
		MediaRoot:     envOr("MEDIAMARK_MEDIA_ROOT", "/media"),
		KeysDir:       envOr("MEDIAMARK_KEYS_DIR", "/etc/mediamark/keys"),
		SonarrURL:     envOr("MEDIAMARK_SONARR_URL", "http://sonarr.arrstack.svc.cluster.local:8989/3aa168/sonarr"),
		RadarrURL:     envOr("MEDIAMARK_RADARR_URL", "http://radarr.arrstack.svc.cluster.local:7878/3aa168/radarr"),
		GroupsHeader:  envOr("MEDIAMARK_GROUPS_HEADER", "X-Forwarded-Groups"),
		AllowedGroups: ParseGroups(envOr("MEDIAMARK_ALLOWED_GROUPS", "akP-mediamark-user")),
	}

	if len(c.AllowedGroups) == 0 {
		return nil, fmt.Errorf("MEDIAMARK_ALLOWED_GROUPS must name at least one group")
	}
	if strings.TrimSpace(c.GroupsHeader) == "" {
		return nil, fmt.Errorf("MEDIAMARK_GROUPS_HEADER must not be empty")
	}
	if !filepath.IsAbs(c.MediaRoot) {
		return nil, fmt.Errorf("MEDIAMARK_MEDIA_ROOT %q must be an absolute path", c.MediaRoot)
	}
	c.MediaRoot = filepath.Clean(c.MediaRoot)
	for _, u := range []struct{ name, val string }{{"MEDIAMARK_SONARR_URL", c.SonarrURL}, {"MEDIAMARK_RADARR_URL", c.RadarrURL}} {
		if !strings.HasPrefix(u.val, "http://") && !strings.HasPrefix(u.val, "https://") {
			return nil, fmt.Errorf("%s %q must be an http(s) URL", u.name, u.val)
		}
	}
	return c, nil
}

// ParseGroups splits a group list tolerating both comma and whitespace
// separation, dropping empties. oauth2-proxy emits comma-separated groups but
// deployments hand-write the allow-list.
func ParseGroups(s string) []string {
	fields := strings.FieldsFunc(s, func(r rune) bool {
		return r == ',' || r == ' ' || r == '\t' || r == '\n' || r == '\r' || r == ';'
	})
	out := make([]string, 0, len(fields))
	for _, f := range fields {
		if f = strings.TrimSpace(f); f != "" {
			out = append(out, f)
		}
	}
	return out
}

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