package web

import (
	"path"
	"path/filepath"
	"sort"
	"strings"

	"gitea.dooplex.hu/admin/felhom-controller/internal/appbackup"
	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
	"gitea.dooplex.hu/admin/felhom-controller/internal/stacks"
	"gitea.dooplex.hu/admin/felhom-controller/internal/system"
)

// „Hova tegyem a fájlokat?" — the app-page folder card (R-75).
//
// Rendered only for DEPLOYED apps that declare data_paths or media_library (Fork-2: all catalog apps get the
// skeleton, but only deployed apps get a UI affordance — an empty folder for an app nobody installed
// is the thing that would actually confuse someone).

// DataPathCard is one folder row on the app page.
type DataPathCard struct {
	Label       string // the catalog's Hungarian label
	Link        string // FileBrowser deep link; "" = the folder's source is not on the box now — shown as text
	Consequence string // class-DRIVEN copy (never hand-written per app)
	IsImport    bool   // drives the free-space line
	FreeSpace   string // system-drive headroom, import rows only ("" when unreadable)
	Role        stacks.DataPathRole
	IsMedia     bool // a per-drive media folder (media_library), not a declared data_path
}

// consequenceFor maps a folder's DERIVED BACKUP CLASS to the sentence the customer reads (Fork-4).
//
// It is driven by the class, not by the role and not by a per-app string, so the promise the UI makes
// can never drift from what the backup engines actually do. `excluded` means the tier filter drops it
// at EVERY tier — so a drop-zone must say, in the customer's own language, that the folder is
// temporary and unbacked. Saying anything softer would be a false promise about their files.
// R-589/R-590 (v0.258.0): `msg` renders the sentence in the HOUSEHOLD'S language. It is a
// parameter rather than a package-level lookup because this sentence is a PROMISE ABOUT THE
// CUSTOMER'S FILES — an English household reading „nem készül róla biztonsági mentés" as decoration
// may leave originals in a drop-zone the backup filter discards at every tier. Found live on
// 2026-09-20 with the folder's own label already English above it, so the line read half and half.
func consequenceFor(class appbackup.BindClass, role stacks.DataPathRole, msg func(key string) string) string {
	switch class {
	case appbackup.ClassExcluded:
		if role == stacks.RoleImport {
			return msg("datapath.consequence.import_excluded")
		}
		return msg("datapath.consequence.excluded")
	case appbackup.ClassMandatory, appbackup.ClassOptional:
		return msg("datapath.consequence.kept")
	default:
		// No classification (legacy app, or a bind with no backup block). Say nothing rather than
		// guess — an unverified backup promise is worse than no sentence at all.
		return ""
	}
}

// buildDataPathCards turns an app's validated data_paths into rendered rows.
//
// classOf resolves a (root, relpath) to its backup class; missing ⇒ empty class ⇒ no consequence
// line. A row whose deep link cannot be built (no domain) is dropped rather than rendered dead.
func (s *Server) buildDataPathCards(st *stacks.Stack, lang string) []DataPathCard {
	msg := func(key string) string { return s.msgLang(lang, key) }
	if st == nil || !st.Deployed || (len(st.Meta.DataPaths) == 0 && st.Meta.MediaLibrary == nil) {
		return nil
	}
	domain := s.cfg.Customer.Domain
	if domain == "" {
		return nil
	}

	classOf := map[string]appbackup.BindClass{}
	if binds, has := s.stackMgr.ClassifiedBinds(st.Name); has {
		for _, b := range binds {
			classOf[string(b.Root)+"\x00"+b.RelPath] = b.Class
		}
	}

	var freeSpace string
	if s.stackMgr != nil {
		if root := s.stackMgr.GetImportRoot(); root != "" {
			if du := system.GetDiskUsage(root); du != nil {
				freeSpace = s.msgLang(lang, "datapath.free_space", du.AvailGB)
			}
		}
	}

	cards := make([]DataPathCard, 0, len(st.Meta.DataPaths))
	for _, dp := range st.Meta.DataPaths {
		var link string
		switch dp.Root {
		case appbackup.RootImport:
			link = importFolderLink(domain, dp.Path)
		case appbackup.RootUserdata:
			// A userdata folder lives on the app's OWN drive, so its FileBrowser source is that
			// drive's sidebar entry. Resolve it from the app's HDD_PATH. v0.320.0: a source that is not
			// on the box now (no drive resolved, or the drive is not present, so FileBrowser does not
			// bind it) is TEXT, never a link — a link to a missing source opens an empty or broken view.
			src, drive := s.fbSourceForApp(st.Name)
			if src != "" && s.drivePresent(drive) {
				link = fileBrowserLink(domain, src, dp.Path)
			} else {
				s.logger.Printf("[WARN] [web] app page %s: folder %q has no FileBrowser source on this box now (drive %q) — shown without a link", st.Name, dp.Path, drive)
			}
		default:
			// hdd: app-internal (appdata/) — NOT customer-browsable, FileBrowser does not mount it.
			// Surfacing a link here would 404. Skipped deliberately; the catalog should not annotate
			// an hdd path with a customer-facing role.
			continue
		}
		isImport := dp.Role == stacks.RoleImport
		card := DataPathCard{
			Label:       dp.Label,
			Link:        link,
			Consequence: consequenceFor(classOf[string(dp.Root)+"\x00"+dp.Path], dp.Role, msg),
			IsImport:    isImport,
			Role:        dp.Role,
		}
		if isImport {
			// The system SSD filling is a different severity from a data drive filling — it can take
			// the whole guest down — and the customer has no other signal that the drop-zone is not
			// bottomless.
			card.FreeSpace = freeSpace
		}
		cards = append(cards, card)
	}
	return append(cards, s.mediaFolderCards(st, domain, lang, cards)...)
}

// mediaLibraryFolders are the `media/` subfolders a whole-media app's library uses — the folders internal/mediawire
// wires into it (Sonarr `tv`, Radarr `movies`, the players both). An app the table does not name gets the `media`
// folder itself. A download client's `media_library.folder` (qBittorrent `torrents`) is its one folder.
var mediaLibraryFolders = map[string][]string{
	"sonarr":   {"tv"},
	"radarr":   {"movies"},
	"plex":     {"movies", "tv"},
	"jellyfin": {"movies", "tv"},
	"emby":     {"movies", "tv"},
}

// mediaFolderLabelKeys name each media subfolder for the household. A folder with no key is shown by its name.
var mediaFolderLabelKeys = map[string]string{
	"":             "datapath.media.root",
	"movies":       "datapath.media.movies",
	"tv":           "datapath.media.tv",
	"torrents":     "datapath.media.downloads",
	"transmission": "datapath.media.downloads",
}

// mediaFolderCards lists, for a media app (`media_library:`), each enrolled drive's media folders the app uses
// (`15-media-library.md` §2). A present drive's folder is a link into that drive's FileBrowser source; a drive that
// is not present is text, with one WARN. No consequence line: the bind's class says the folder is not THIS app's
// data (Sonarr/Radarr/the players declare it `excluded`), which is not the sentence „temporary, not backed up" —
// and the per-drive binds are in no classifier at all (`15` §7). An unverified backup promise is worse than none.
// A folder a declared data_path already links to is not listed twice.
func (s *Server) mediaFolderCards(st *stacks.Stack, domain, lang string, have []DataPathCard) []DataPathCard {
	spec := st.Meta.MediaLibrary
	if spec == nil || s.settings == nil {
		return nil
	}
	subs := mediaLibraryFolders[st.Meta.Slug]
	if f := strings.Trim(path.Clean("/"+spec.Folder), "/"); f != "" {
		subs = []string{f}
	} else if len(subs) == 0 {
		subs = []string{""}
	}
	seen := map[string]bool{}
	for _, c := range have {
		if c.Link != "" {
			seen[c.Link] = true
		}
	}
	var out []DataPathCard
	for _, sp := range s.mediaStoragePaths() {
		src := fbSourceName(sp)
		present := s.drivePresent(sp.Path)
		if !present {
			s.logger.Printf("[WARN] [web] app page %s: drive %q is not present — its media folders are shown without a link", st.Name, sp.Path)
		}
		for _, sub := range subs {
			label := sub
			if k, ok := mediaFolderLabelKeys[sub]; ok {
				label = s.msgLang(lang, k)
			}
			card := DataPathCard{Label: s.msgLang(lang, "datapath.media.row", label, src), Role: stacks.RoleLibrary, IsMedia: true}
			if present {
				card.Link = fileBrowserLink(domain, src, path.Join("media", sub))
				if seen[card.Link] {
					continue
				}
				seen[card.Link] = true
			}
			out = append(out, card)
		}
	}
	return out
}

// mediaStoragePaths are the drives a media app binds: enrolled, not network, not decommissioned (the same set
// stacks.mediaDrives starts from), sorted by path so the first drive is stable.
func (s *Server) mediaStoragePaths() []settings.StoragePath {
	var out []settings.StoragePath
	seen := map[string]bool{}
	for _, sp := range s.settings.GetStoragePaths() {
		p := filepath.Clean(sp.Path)
		if sp.Kind == "network" || sp.Decommissioned || sp.Path == "" || seen[p] {
			continue
		}
		seen[p] = true
		sp.Path = p
		out = append(out, sp)
	}
	sort.Slice(out, func(i, j int) bool { return out[i].Path < out[j].Path })
	return out
}

// drivePresent reports whether a drive is bound into FileBrowser now: the stack manager's present media drives
// (enrolled, mounted, not dead, not safely removed) — the same gates buildFileBrowserPaths applies.
func (s *Server) drivePresent(drive string) bool {
	if drive == "" {
		return false
	}
	var present []string
	switch {
	case s.presentDrivesFn != nil:
		present = s.presentDrivesFn()
	case s.stackMgr != nil:
		present = s.stackMgr.PresentMediaDrives()
	}
	for _, p := range present {
		if filepath.Clean(p) == filepath.Clean(drive) {
			return true
		}
	}
	return false
}

// filesButtonLink is the target of the app header's „Fajlok" button: the first folder with the library role, else
// the first declared folder, else (a media app) the first present drive's `media` folder. Only folders that are a
// link count. "" = no button (an app with no folder on the box, e.g. Immich's data in a named volume).
func (s *Server) filesButtonLink(st *stacks.Stack, cards []DataPathCard) string {
	for _, c := range cards {
		if !c.IsMedia && c.Link != "" && c.Role == stacks.RoleLibrary {
			return c.Link
		}
	}
	for _, c := range cards {
		if !c.IsMedia && c.Link != "" {
			return c.Link
		}
	}
	if st == nil || st.Meta.MediaLibrary == nil || s.settings == nil || s.cfg.Customer.Domain == "" {
		return ""
	}
	for _, sp := range s.mediaStoragePaths() {
		if s.drivePresent(sp.Path) {
			return fileBrowserLink(s.cfg.Customer.Domain, fbSourceName(sp), "media")
		}
	}
	return ""
}

// fbSourceNameForApp returns the FileBrowser sidebar source name for the drive an app is deployed
// on: the storage path's label when it has one, else the mount basename — exactly what
// RenderFileBrowserConfig emits, so the deep link and the sidebar can never disagree.
func (s *Server) fbSourceNameForApp(stackName string) string {
	src, _ := s.fbSourceForApp(stackName)
	return src
}

// fbSourceForApp is fbSourceNameForApp plus the drive path it resolved ("" when none).
func (s *Server) fbSourceForApp(stackName string) (source, drive string) {
	appCfg := s.stackMgr.LoadAppConfigByName(stackName)
	if appCfg == nil {
		return "", ""
	}
	hdd := appCfg.Env["HDD_PATH"]
	if hdd == "" {
		return "", ""
	}
	for _, sp := range s.settings.GetStoragePaths() {
		if sp.Path != hdd || sp.Decommissioned {
			continue
		}
		return fbSourceName(sp), sp.Path
	}
	return "", hdd
}

// fbSourceName is a drive's FileBrowser sidebar name: its label, else the mount basename — exactly what
// infra.RenderFileBrowserConfig emits, so a link and the sidebar cannot disagree.
func fbSourceName(sp settings.StoragePath) string {
	if sp.Label != "" {
		return sp.Label
	}
	return filepath.Base(sp.Path)
}