package api

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"path"
	"strings"
)

// This file exposes the "localstorage" (host local filesystem) plugin's settings
// to end users through the same three-layer cascade OpenSky and filetransfer use
// (superadmin/global → organization → user); see integrations.go for the shared
// helpers (lockedFor, layerRank, maskPresent, callerFromRecord, boolStr).
//
//   - global (L1): the plugin's config in plugins.json, set in the API Server panel
//     (the storage root basePath + the master switch + a global read-only default).
//   - org    (L2): pluginSettings.localstorage on the caller's organization record.
//   - user   (L3): pluginSettings.localstorage on the caller's own user record.
//
// Unlike filetransfer, a local drive gives each tenant *isolated* folders rather
// than a freely-chosen path. Folders are derived from identity, never taken from a
// client, and laid out so that "private" is genuinely private:
//
//   <root>/orgs/<orgId>/shared          — the organization folder (all members)
//   <root>/orgs/<orgId>/private/<userId>— a member's private folder (opt-in)
//   <root>/users/<userId>               — an org-less user's private folder
//
// A member on the shared folder is confined to .../shared and cannot traverse into
// anyone's .../private subtree; each private folder is confined to its own
// .../private/<userId>. So an org member can hold BOTH the shared org folder and a
// private folder nested inside the org folder, reachable only by them. The plugin
// confines every operation within the folder it is handed, so isolation is enforced
// end-to-end.
//
// A member opts into their private folder personally (user layer); an org admin may
// gate the feature for the whole organization (org layer, default allowed). The one
// other cascading tunable is readOnly (blank falls through, top wins, a set value
// locks lower layers).

const localStoragePlugin = "localstorage"

// lsConfig is one layer's editable localstorage settings. Folders are not here:
// they are computed from identity, never stored or taken from a client.
type lsConfig struct {
	ReadOnly string `json:"readOnly"` // "" (inherit) | "true" | "false"
}

// lsStored is what we persist per user/org under pluginSettings.localstorage.
type lsStored struct {
	Config lsConfig `json:"config"`
	// Enabled is the personal per-user opt-in (user layer). Default false.
	Enabled bool `json:"enabled"`
	// Disabled is the organization layer's off switch, stored inverted so that
	// absent == enabled (mirrors OpenSky). Only meaningful on the org record.
	Disabled bool `json:"disabled,omitempty"`
	// PrivateFolder is the user layer's opt-in for a private folder inside the org
	// folder. Only meaningful for a caller who belongs to an organization.
	PrivateFolder bool `json:"privateFolder,omitempty"`
	// DisallowPrivate is the org layer's gate on private folders, stored inverted so
	// that absent == allowed. Only meaningful on the org record.
	DisallowPrivate bool `json:"disallowPrivate,omitempty"`
}

// lsSettingsDoc is the localstorage slice of the shared pluginSettings JSON.
type lsSettingsDoc struct {
	LocalStorage lsStored `json:"localstorage"`
}

// lsMount is one isolated folder a caller can reach.
type lsMount struct {
	ID    string `json:"id"`    // "shared" | "private" | "personal"
	Label string `json:"label"` // human label for the UI
	Path  string `json:"path"`  // absolute folder path
	Kind  string `json:"kind"`  // "shared" | "private"
}

// lsResolution is the fully-resolved localstorage state for one caller.
type lsResolution struct {
	readOnly     string            // effective read-only ("" | "true" | "false")
	userReadOnly string            // user (L3) read-only value
	orgReadOnly  string            // organization (L2) read-only value
	root         string            // global storage root
	mounts       []lsMount         // isolated folders in force for this caller
	source       map[string]string // field -> layer name (global|org|user|unset)
	isSuper      bool
	canOrg       bool
	available    bool // global master switch
	orgEnabled   bool // org master switch (default true)
	enabled      bool // personal opt-in to use the plugin
	isOrgUser    bool // caller belongs to an organization
	allowPrivate bool // org policy: private folders permitted (default true)
	wantsPrivate bool // user's raw private-folder opt-in
	privateOn    bool // effective: org user + allowed + opted in
}

// Folder builders. Forward-slash joins (path, not filepath) since the target host
// is Linux; the plugin re-resolves against the OS filesystem and confines within.
func orgSharedFolder(root, orgID string) string {
	return path.Join(root, "orgs", orgID, "shared")
}
func orgPrivateFolder(root, orgID, userID string) string {
	return path.Join(root, "orgs", orgID, "private", userID)
}
func userPersonalFolder(root, userID string) string {
	return path.Join(root, "users", userID)
}

// tenantMounts computes the isolated folders for a caller. An org member always
// gets the shared org folder and, when privateOn, an additional private folder
// nested inside the org folder; an org-less user gets a single private folder.
func tenantMounts(root string, who *callerIdentity, privateOn bool) []lsMount {
	root = strings.TrimSpace(root)
	if root == "" {
		return []lsMount{}
	}
	if who.OrgID != "" {
		mounts := []lsMount{{
			ID: "shared", Label: "Organization folder", Kind: "shared",
			Path: orgSharedFolder(root, who.OrgID),
		}}
		if privateOn && who.ID != "" {
			mounts = append(mounts, lsMount{
				ID: "private", Label: "Your private folder", Kind: "private",
				Path: orgPrivateFolder(root, who.OrgID, who.ID),
			})
		}
		return mounts
	}
	if who.ID != "" {
		return []lsMount{{
			ID: "personal", Label: "Your private folder", Kind: "private",
			Path: userPersonalFolder(root, who.ID),
		}}
	}
	return []lsMount{}
}

// resolveLocalStorage computes the cascade for a caller. userRaw is the caller's
// pluginSettings blob (from their auth-refresh record).
func (s *Server) resolveLocalStorage(ctx context.Context, who *callerIdentity, userRaw json.RawMessage) lsResolution {
	g, masterEnabled, _ := s.plugins.RawConfig(localStoragePlugin)
	root := strings.TrimSpace(g["basePath"])
	// The global panel's readOnly select defaults to a concrete "false"; treat that
	// as unset so the global default does not permanently lock lower layers. Only an
	// explicit global "true" freezes every folder.
	globalRO := strings.TrimSpace(g["readOnly"])
	if strings.EqualFold(globalRO, "false") {
		globalRO = ""
	}

	var oStored lsStored
	if who.OrgID != "" {
		oStored, _ = s.orgLocalStorage(ctx, who.OrgID)
	}
	var uStored lsStored
	if len(userRaw) > 0 {
		var d lsSettingsDoc
		_ = json.Unmarshal(userRaw, &d)
		uStored = d.LocalStorage
	}

	res := lsResolution{
		source:       map[string]string{},
		userReadOnly: uStored.Config.ReadOnly,
		orgReadOnly:  oStored.Config.ReadOnly,
		isSuper:      who.isSuperadmin(),
		// An org admin may edit the organization layer in addition to their own.
		// Requires the service account (org writes go through it).
		canOrg:       who.isManager() && !who.isSuperadmin() && who.OrgID != "" && s.admin.configured(),
		available:    masterEnabled,
		orgEnabled:   !oStored.Disabled,
		enabled:      uStored.Enabled,
		root:         root,
		isOrgUser:    who.OrgID != "",
		allowPrivate: !oStored.DisallowPrivate, // default allowed
		wantsPrivate: uStored.PrivateFolder,
	}

	// readOnly cascades top-wins, blanks fall through (same mechanism as OpenSky).
	type layer struct{ name, ro string }
	layers := []layer{{"global", globalRO}}
	if who.OrgID != "" {
		layers = append(layers, layer{"org", oStored.Config.ReadOnly})
	}
	layers = append(layers, layer{"user", uStored.Config.ReadOnly})
	roSrc := "unset"
	for _, l := range layers {
		if v := strings.TrimSpace(l.ro); v != "" {
			res.readOnly, roSrc = v, l.name
			break
		}
	}
	res.source["readOnly"] = roSrc

	// Effective private-folder state and the isolated folders in force.
	res.privateOn = res.isOrgUser && res.allowPrivate && res.wantsPrivate
	res.mounts = tenantMounts(root, who, res.privateOn)
	return res
}

// orgLocalStorage reads an organization's stored localstorage settings (config +
// the org gate) and its raw pluginSettings blob via the service account. Best
// effort: zero values on any miss so callers proceed as if the org layer were empty.
func (s *Server) orgLocalStorage(ctx context.Context, orgID string) (lsStored, json.RawMessage) {
	if orgID == "" || !s.admin.configured() {
		return lsStored{}, nil
	}
	data, status, err := s.admin.do(ctx, http.MethodGet,
		"/api/collections/organizations/records/"+url.PathEscape(orgID)+"?fields=pluginSettings", nil)
	if err != nil || status != http.StatusOK {
		return lsStored{}, nil
	}
	var rec struct {
		PluginSettings json.RawMessage `json:"pluginSettings"`
	}
	_ = json.Unmarshal(data, &rec)
	var doc lsSettingsDoc
	if len(rec.PluginSettings) > 0 {
		_ = json.Unmarshal(rec.PluginSettings, &doc)
	}
	return doc.LocalStorage, rec.PluginSettings
}

// mergeLocalStorage applies a mutation to the localstorage entry of a
// pluginSettings blob, preserving any other plugin keys, and returns the new blob.
func mergeLocalStorage(existing json.RawMessage, apply func(*lsStored)) json.RawMessage {
	doc := map[string]json.RawMessage{}
	if len(existing) > 0 {
		_ = json.Unmarshal(existing, &doc)
	}
	if doc == nil {
		doc = map[string]json.RawMessage{} // existing was JSON null
	}
	var ls lsStored
	if raw, ok := doc["localstorage"]; ok {
		_ = json.Unmarshal(raw, &ls)
	}
	apply(&ls)
	b, _ := json.Marshal(ls)
	doc["localstorage"] = b
	out, _ := json.Marshal(doc)
	return out
}

// GET /api/integrations/localstorage — resolved view for the caller.
func (s *Server) handleGetLocalStorage(w http.ResponseWriter, r *http.Request) {
	who, userRaw, ok := s.integrationCaller(w, r)
	if !ok {
		return
	}
	res := s.resolveLocalStorage(r.Context(), who, userRaw)
	writeJSON(w, http.StatusOK, s.localStorageView(who, res))
}

// lsScopeView builds the field set for one editable scope. editable is the layer
// the caller edits ("user" | "org" | "none"); readOnly is locked when its effective
// value is set above that layer.
func (s *Server) lsScopeView(res lsResolution, editable string) map[string]any {
	own := res.userReadOnly
	if editable == "org" {
		own = res.orgReadOnly
	}
	src := res.source["readOnly"]
	field := osFieldView{
		Source:    src,
		Locked:    lockedFor(src, editable),
		Effective: res.readOnly,
		Own:       own,
	}
	return map[string]any{
		"editableLayer": editable,
		"fields":        map[string]osFieldView{"readOnly": field},
	}
}

// localStorageView builds the client-safe response body. It exposes a "user" scope
// for everyone plus, for org admins, an "org" scope. The effective isolated folders
// are reported at the top level (derived, not editable).
func (s *Server) localStorageView(who *callerIdentity, res lsResolution) map[string]any {
	out := map[string]any{
		"available":      res.available,
		"orgEnabled":     res.orgEnabled,
		"enabled":        res.enabled,
		"role":           who.Role,
		"orgId":          who.OrgID,
		"canEditOrg":     res.canOrg,
		"isSuperadmin":   res.isSuper,
		"isOrgUser":      res.isOrgUser,
		"rootConfigured": strings.TrimSpace(res.root) != "",
		"mounts":         res.mounts,
		"privateFolder":  res.wantsPrivate, // the user's own opt-in
		"privateEnabled": res.privateOn,    // effective (may be gated off by the org)
		"allowPrivate":   res.allowPrivate, // org policy
	}
	if res.isSuper {
		out["editableLayer"] = "none"
		out["scopes"] = map[string]any{"user": s.lsScopeView(res, "none")}
		return out
	}
	scopes := map[string]any{"user": s.lsScopeView(res, "user")}
	if res.canOrg {
		scopes["org"] = s.lsScopeView(res, "org")
	}
	out["scopes"] = scopes
	return out
}

// PUT /api/integrations/localstorage — save the caller's editable layer. Body:
// {enabled?, privateFolder?, allowPrivate?, scope?, config?}. Folders are derived,
// so only readOnly, the enable flags, and the private-folder settings are writable.
func (s *Server) handlePutLocalStorage(w http.ResponseWriter, r *http.Request) {
	token := r.Header.Get("Authorization")
	var body struct {
		Enabled       *bool             `json:"enabled"`
		PrivateFolder *bool             `json:"privateFolder"` // user: opt into a private folder
		AllowPrivate  *bool             `json:"allowPrivate"`  // org: permit private folders
		Scope         string            `json:"scope"`
		Config        map[string]string `json:"config"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		writeError(w, http.StatusBadRequest, "invalid json")
		return
	}
	who, userRaw, ok := s.integrationCaller(w, r)
	if !ok {
		return
	}
	res := s.resolveLocalStorage(r.Context(), who, userRaw)

	// Resolve which layer this write targets.
	editable := "user"
	switch {
	case res.isSuper:
		editable = "none"
	case strings.EqualFold(strings.TrimSpace(body.Scope), "org"):
		if !res.canOrg {
			writeError(w, http.StatusForbidden, "only an organization admin can edit organization settings")
			return
		}
		editable = "org"
	}

	// Overlay readOnly onto the target scope's own value, unless it is locked above.
	newRO := res.userReadOnly
	if editable == "org" {
		newRO = res.orgReadOnly
	}
	if v, present := body.Config["readOnly"]; present && !lockedFor(res.source["readOnly"], editable) {
		newRO = normalizeReadOnly(v)
	}

	// Persist the organization layer (admins) via the service account.
	if editable == "org" {
		if who.OrgID == "" {
			writeError(w, http.StatusForbidden, "your account is not attached to an organization")
			return
		}
		if !s.admin.configured() {
			writeError(w, http.StatusServiceUnavailable, "organization settings not configured on the server")
			return
		}
		_, orgRaw := s.orgLocalStorage(r.Context(), who.OrgID)
		newDoc := mergeLocalStorage(orgRaw, func(ls *lsStored) {
			ls.Config.ReadOnly = newRO
			if body.Enabled != nil {
				ls.Disabled = !*body.Enabled // org master switch, stored inverted
			}
			if body.AllowPrivate != nil {
				ls.DisallowPrivate = !*body.AllowPrivate // stored inverted (absent = allowed)
			}
		})
		_, st, err := s.admin.do(r.Context(), http.MethodPatch,
			"/api/collections/organizations/records/"+url.PathEscape(who.OrgID),
			map[string]json.RawMessage{"pluginSettings": newDoc})
		if err != nil {
			writeJSON(w, http.StatusBadGateway, map[string]any{"error": "cannot reach PocketBase", "detail": err.Error()})
			return
		}
		if st != http.StatusOK {
			writeError(w, http.StatusBadGateway, "could not save organization settings")
			return
		}
	}

	// Persist the user record: the personal enable flag and private-folder opt-in
	// live here (user/superadmin scope), and so does the personal readOnly when this
	// write targets the user scope.
	personalEnable := body.Enabled != nil && editable != "org"
	personalPrivate := body.PrivateFolder != nil && editable != "org"
	if personalEnable || personalPrivate || editable == "user" {
		newDoc := mergeLocalStorage(userRaw, func(ls *lsStored) {
			if personalEnable {
				ls.Enabled = *body.Enabled
			}
			if personalPrivate {
				ls.PrivateFolder = *body.PrivateFolder
			}
			if editable == "user" {
				ls.Config.ReadOnly = newRO
			}
		})
		if code, err := s.patchUserPluginSettings(r.Context(), token, who.ID, newDoc); err != nil {
			writeJSON(w, http.StatusBadGateway, map[string]any{"error": "cannot reach PocketBase", "detail": err.Error()})
			return
		} else if code != http.StatusOK {
			writeError(w, http.StatusBadGateway, "could not save user settings")
			return
		}
	}

	// Re-resolve and return the fresh view.
	fresh, st, err := s.pbAuthRefresh(r.Context(), token)
	if err != nil || st != http.StatusOK || fresh == nil {
		writeJSON(w, http.StatusOK, map[string]any{"ok": true})
		return
	}
	res2 := s.resolveLocalStorage(r.Context(), who, fresh.Record["pluginSettings"])
	writeJSON(w, http.StatusOK, s.localStorageView(who, res2))
}

// normalizeReadOnly coerces a submitted readOnly value to the stored vocabulary.
func normalizeReadOnly(v string) string {
	switch strings.ToLower(strings.TrimSpace(v)) {
	case "true":
		return "true"
	case "false":
		return "false"
	default:
		return "" // inherit
	}
}

// POST /api/integrations/localstorage/health — live probe against every isolated
// folder the caller holds (each auto-created), honouring the resolved read-only flag.
func (s *Server) handleLocalStorageHealth(w http.ResponseWriter, r *http.Request) {
	who, userRaw, ok := s.integrationCaller(w, r)
	if !ok {
		return
	}
	if !who.isSuperadmin() {
		if _, _, ok := s.plugins.RawConfig(localStoragePlugin); !ok {
			writeError(w, http.StatusNotFound, "unknown plugin")
			return
		}
	}
	res := s.resolveLocalStorage(r.Context(), who, userRaw)
	if !res.available {
		writeJSON(w, http.StatusOK, map[string]any{"health": map[string]any{
			"status": "down", "detail": "Local storage is disabled by the administrator"}})
		return
	}
	if !res.orgEnabled {
		writeJSON(w, http.StatusOK, map[string]any{"health": map[string]any{
			"status": "down", "detail": "Local storage is disabled for your organization"}})
		return
	}
	if len(res.mounts) == 0 {
		writeJSON(w, http.StatusOK, map[string]any{"health": map[string]any{
			"status": "down", "detail": "No storage root configured by the administrator"}})
		return
	}

	// Probe each folder; aggregate to the worst status for the summary badge and
	// return per-folder results so the UI can annotate each mount.
	perMount := make([]map[string]any, 0, len(res.mounts))
	worst := "ok"
	for _, m := range res.mounts {
		cfg := map[string]string{
			"basePath":      m.Path,
			"createMissing": "true", // each folder is provisioned on demand
			"readOnly":      res.readOnly,
		}
		h, err := s.plugins.HealthCheckWith(r.Context(), localStoragePlugin, cfg)
		status, detail := "down", ""
		if err != nil {
			detail = err.Error()
		} else {
			status, detail = h.Status, h.Detail
		}
		worst = worseStatus(worst, status)
		perMount = append(perMount, map[string]any{
			"id": m.ID, "label": m.Label, "path": m.Path, "status": status, "detail": detail,
		})
	}

	summary := fmt.Sprintf("%d folder%s reachable", len(res.mounts), plural2(len(res.mounts)))
	if worst != "ok" {
		// Surface the first non-ok detail so the badge is actionable.
		for _, m := range perMount {
			if m["status"] != "ok" {
				summary = fmt.Sprintf("%s: %v", m["label"], m["detail"])
				break
			}
		}
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"health": map[string]any{"status": worst, "detail": summary},
		"mounts": perMount,
	})
}

// worseStatus returns the more severe of two health statuses (ok < degraded < down).
func worseStatus(a, b string) string {
	rank := map[string]int{"ok": 0, "degraded": 1, "down": 2}
	if rank[b] > rank[a] {
		return b
	}
	return a
}

func plural2(n int) string {
	if n == 1 {
		return ""
	}
	return "s"
}