package api

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

// This file exposes the "filetransfer" (FTP/FTPS/SFTP) plugin's settings to end
// users through the exact same three-layer cascade OpenSky uses
// (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.
//   - org    (L2): pluginSettings.filetransfer on the caller's organization record.
//   - user   (L3): pluginSettings.filetransfer on the caller's own user record.
//
// Unlike OpenSky's independently-resolved tunables, a file-server connection is
// only meaningful as a whole: you cannot take the host from one layer and the
// credentials from another. So every connection field (protocol, host, port,
// username, password, private key + passphrase, host-key fingerprint, TLS
// verification) resolves as a *group* from the highest layer that supplies a
// host — mirroring how OpenSky resolves its client id + secret as a pair, just
// widened to the whole connection. Only basePath cascades independently, so a
// user can point at their own working directory on an org-provided server.
//
// Secrets are never returned to a lower-privileged client: the effective config
// is resolved server-side and only masked values leave the API. Live probes run
// server-side against the resolved config.

const fileTransferPlugin = "filetransfer"

// ftConfig is one layer's filetransfer settings. Values are strings to match the
// plugin's ConfigField keys 1:1 (they are handed straight to plugins.Init).
type ftConfig struct {
	Protocol           string `json:"protocol"`
	Host               string `json:"host"`
	Port               string `json:"port"`
	Username           string `json:"username"`
	Password           string `json:"password"`
	PrivateKey         string `json:"privateKey"`
	KeyPassphrase      string `json:"keyPassphrase"`
	HostKeyFingerprint string `json:"hostKeyFingerprint"`
	InsecureSkipVerify string `json:"insecureSkipVerify"`
	BasePath           string `json:"basePath"`
}

// ftConnKeys are the fields that resolve together as one connection (everything
// host-specific). basePath is deliberately excluded — it cascades on its own.
var ftConnKeys = []string{
	"protocol", "host", "port", "username", "password",
	"privateKey", "keyPassphrase", "hostKeyFingerprint", "insecureSkipVerify",
}

// ftSecretKeys are masked in every view and preserved on save when left at the mask.
var ftSecretKeys = map[string]bool{"password": true, "privateKey": true, "keyPassphrase": true}

// ftStored is what we persist per user/org under pluginSettings.filetransfer.
type ftStored struct {
	Config ftConfig `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"`
}

// ftSettingsDoc is the filetransfer slice of the shared pluginSettings JSON.
type ftSettingsDoc struct {
	FileTransfer ftStored `json:"filetransfer"`
}

// ftResolution is the fully-resolved filetransfer state for one caller.
type ftResolution struct {
	eff        ftConfig          // effective (unmasked) — used only server-side (probes)
	userOwn    ftConfig          // caller's personal (L3) values (unmasked)
	orgOwn     ftConfig          // organization (L2) values (unmasked)
	source     map[string]string // field -> layer name (global|org|user|unset)
	isSuper    bool              // superadmin: manages the global layer in the panel
	canOrg     bool              // caller may edit the organization layer (org admin)
	available  bool              // global master switch (plugin enabled in the panel)
	orgEnabled bool              // org master switch (default true; gates the org's users)
	enabled    bool              // caller's personal enable flag
}

// ftConfigFromMap builds an ftConfig from a flat string map (global plugin config).
func ftConfigFromMap(m map[string]string) ftConfig {
	return ftConfig{
		Protocol:           m["protocol"],
		Host:               m["host"],
		Port:               m["port"],
		Username:           m["username"],
		Password:           m["password"],
		PrivateKey:         m["privateKey"],
		KeyPassphrase:      m["keyPassphrase"],
		HostKeyFingerprint: m["hostKeyFingerprint"],
		InsecureSkipVerify: m["insecureSkipVerify"],
		BasePath:           m["basePath"],
	}
}

// ftGet returns a config field by the plugin's key name.
func ftGet(c ftConfig, key string) string {
	switch key {
	case "protocol":
		return c.Protocol
	case "host":
		return c.Host
	case "port":
		return c.Port
	case "username":
		return c.Username
	case "password":
		return c.Password
	case "privateKey":
		return c.PrivateKey
	case "keyPassphrase":
		return c.KeyPassphrase
	case "hostKeyFingerprint":
		return c.HostKeyFingerprint
	case "insecureSkipVerify":
		return c.InsecureSkipVerify
	case "basePath":
		return c.BasePath
	}
	return ""
}

// ftSet writes a config field by the plugin's key name.
func ftSet(c *ftConfig, key, v string) {
	switch key {
	case "protocol":
		c.Protocol = v
	case "host":
		c.Host = v
	case "port":
		c.Port = v
	case "username":
		c.Username = v
	case "password":
		c.Password = v
	case "privateKey":
		c.PrivateKey = v
	case "keyPassphrase":
		c.KeyPassphrase = v
	case "hostKeyFingerprint":
		c.HostKeyFingerprint = v
	case "insecureSkipVerify":
		c.InsecureSkipVerify = v
	case "basePath":
		c.BasePath = v
	}
}

// resolveFileTransfer computes the cascade for a caller. userRaw is the caller's
// pluginSettings blob (from their auth-refresh record).
func (s *Server) resolveFileTransfer(ctx context.Context, who *callerIdentity, userRaw json.RawMessage) ftResolution {
	g, masterEnabled, _ := s.plugins.RawConfig(fileTransferPlugin)
	gc := ftConfigFromMap(g)

	var oStored ftStored
	if who.OrgID != "" {
		oStored, _ = s.orgFileTransfer(ctx, who.OrgID)
	}
	oc := oStored.Config

	var uStored ftStored
	if len(userRaw) > 0 {
		var d ftSettingsDoc
		_ = json.Unmarshal(userRaw, &d)
		uStored = d.FileTransfer
	}
	uc := uStored.Config

	res := ftResolution{
		source:  map[string]string{},
		userOwn: uc,
		orgOwn:  oc,
		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,
	}

	// Ordered layers, top (highest priority) first.
	type layer struct {
		name string
		c    ftConfig
	}
	layers := []layer{{"global", gc}}
	if who.OrgID != "" {
		layers = append(layers, layer{"org", oc})
	}
	layers = append(layers, layer{"user", uc})

	// Connection group: the whole connection comes from the highest layer that
	// supplies a host, so credential halves are never mixed across layers.
	connSrc := "unset"
	for _, l := range layers {
		if strings.TrimSpace(l.c.Host) != "" {
			for _, k := range ftConnKeys {
				ftSet(&res.eff, k, ftGet(l.c, k))
			}
			connSrc = l.name
			break
		}
	}
	for _, k := range ftConnKeys {
		res.source[k] = connSrc
	}

	// basePath cascades independently, top wins, blanks fall through.
	baseSrc := "unset"
	for _, l := range layers {
		if v := strings.TrimSpace(l.c.BasePath); v != "" {
			res.eff.BasePath, baseSrc = v, l.name
			break
		}
	}
	res.source["basePath"] = baseSrc
	return res
}

// orgFileTransfer reads an organization's stored filetransfer 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) orgFileTransfer(ctx context.Context, orgID string) (ftStored, json.RawMessage) {
	if orgID == "" || !s.admin.configured() {
		return ftStored{}, 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 ftStored{}, nil
	}
	var rec struct {
		PluginSettings json.RawMessage `json:"pluginSettings"`
	}
	_ = json.Unmarshal(data, &rec)
	var doc ftSettingsDoc
	if len(rec.PluginSettings) > 0 {
		_ = json.Unmarshal(rec.PluginSettings, &doc)
	}
	return doc.FileTransfer, rec.PluginSettings
}

// mergeFileTransfer applies a mutation to the filetransfer entry of a
// pluginSettings blob, preserving any other plugin keys (e.g. opensky), and
// returns the new blob.
func mergeFileTransfer(existing json.RawMessage, apply func(*ftStored)) 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 ft ftStored
	if raw, ok := doc["filetransfer"]; ok {
		_ = json.Unmarshal(raw, &ft)
	}
	apply(&ft)
	b, _ := json.Marshal(ft)
	doc["filetransfer"] = b
	out, _ := json.Marshal(doc)
	return out
}

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

// ftScopeView builds the masked field set for one editable scope. editable is the
// layer the caller edits ("user" | "org" | "none"); a field is locked when its
// effective value is set above that layer.
func (s *Server) ftScopeView(res ftResolution, editable string) map[string]any {
	own := res.userOwn
	if editable == "org" {
		own = res.orgOwn
	}
	fields := map[string]osFieldView{}
	for _, key := range append(append([]string{}, ftConnKeys...), "basePath") {
		src := res.source[key]
		fv := osFieldView{Source: src, Locked: lockedFor(src, editable)}
		if ftSecretKeys[key] {
			fv.Effective, fv.Own = maskPresent(ftGet(res.eff, key)), maskPresent(ftGet(own, key))
		} else {
			fv.Effective, fv.Own = ftGet(res.eff, key), ftGet(own, key)
		}
		fields[key] = fv
	}
	return map[string]any{"editableLayer": editable, "fields": fields}
}

// fileTransferView builds the masked, client-safe response body. It exposes a
// "user" scope for everyone plus, for org admins, an "org" scope.
func (s *Server) fileTransferView(who *callerIdentity, res ftResolution) 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,
	}
	if res.isSuper {
		out["editableLayer"] = "none"
		out["scopes"] = map[string]any{"user": s.ftScopeView(res, "none")}
		return out
	}
	scopes := map[string]any{"user": s.ftScopeView(res, "user")}
	if res.canOrg {
		scopes["org"] = s.ftScopeView(res, "org")
	}
	out["scopes"] = scopes
	return out
}

// PUT /api/integrations/filetransfer — save the caller's editable layer. Body:
// {enabled?, scope?, config?}. Fields locked above the caller are ignored; a
// secret left at the mask is preserved.
func (s *Server) handlePutFileTransfer(w http.ResponseWriter, r *http.Request) {
	token := r.Header.Get("Authorization")
	var body struct {
		Enabled *bool             `json:"enabled"`
		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.resolveFileTransfer(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 the fields the caller may change in this scope onto its own values.
	newOwn := res.userOwn
	if editable == "org" {
		newOwn = res.orgOwn
	}
	for _, key := range append(append([]string{}, ftConnKeys...), "basePath") {
		v, present := body.Config[key]
		if !present || lockedFor(res.source[key], editable) {
			continue
		}
		if ftSecretKeys[key] && v == openSkySecretMask {
			continue // keep current secret
		}
		ftSet(&newOwn, key, strings.TrimSpace(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.orgFileTransfer(r.Context(), who.OrgID)
		newDoc := mergeFileTransfer(orgRaw, func(ft *ftStored) {
			ft.Config = newOwn
			if body.Enabled != nil {
				ft.Disabled = !*body.Enabled // org master switch, stored inverted
			}
		})
		_, 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 lives here (user/superadmin
	// scope), and so does the personal config layer when this write targets user.
	personalEnable := body.Enabled != nil && editable != "org"
	if personalEnable || editable == "user" {
		newDoc := mergeFileTransfer(userRaw, func(ft *ftStored) {
			if personalEnable {
				ft.Enabled = *body.Enabled
			}
			if editable == "user" {
				ft.Config = newOwn
			}
		})
		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.resolveFileTransfer(r.Context(), who, fresh.Record["pluginSettings"])
	writeJSON(w, http.StatusOK, s.fileTransferView(who, res2))
}

// POST /api/integrations/filetransfer/health — live probe using the caller's
// resolved config. Never returns secrets.
func (s *Server) handleFileTransferHealth(w http.ResponseWriter, r *http.Request) {
	who, userRaw, ok := s.integrationCaller(w, r)
	if !ok {
		return
	}
	if !who.isSuperadmin() {
		if _, _, ok := s.plugins.RawConfig(fileTransferPlugin); !ok {
			writeError(w, http.StatusNotFound, "unknown plugin")
			return
		}
	}
	res := s.resolveFileTransfer(r.Context(), who, userRaw)
	if !res.available {
		writeJSON(w, http.StatusOK, map[string]any{"health": map[string]any{
			"status": "down", "detail": "File transfer is disabled by the administrator"}})
		return
	}
	if !res.orgEnabled {
		writeJSON(w, http.StatusOK, map[string]any{"health": map[string]any{
			"status": "down", "detail": "File transfer is disabled for your organization"}})
		return
	}
	if strings.TrimSpace(res.eff.Host) == "" {
		writeJSON(w, http.StatusOK, map[string]any{"health": map[string]any{
			"status": "down", "detail": "No server configured — set a host to connect"}})
		return
	}
	cfg := map[string]string{}
	for _, k := range append(append([]string{}, ftConnKeys...), "basePath") {
		cfg[k] = ftGet(res.eff, k)
	}
	h, err := s.plugins.HealthCheckWith(r.Context(), fileTransferPlugin, cfg)
	if err != nil {
		writeJSON(w, http.StatusBadGateway, map[string]any{"error": err.Error()})
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"health": h})
}

// integrationCaller authenticates the request via a PocketBase auth-refresh and
// returns the caller identity plus their pluginSettings blob. It writes the error
// response and returns ok=false on any failure. Shared by the filetransfer
// integration endpoints (the OpenSky handlers predate it and inline the same steps).
func (s *Server) integrationCaller(w http.ResponseWriter, r *http.Request) (*callerIdentity, json.RawMessage, bool) {
	token := r.Header.Get("Authorization")
	if token == "" {
		writeError(w, http.StatusUnauthorized, "missing token")
		return nil, nil, false
	}
	rec, status, err := s.pbAuthRefresh(r.Context(), token)
	if err != nil {
		writeJSON(w, http.StatusBadGateway, map[string]any{"error": "cannot reach PocketBase", "detail": err.Error()})
		return nil, nil, false
	}
	if status != http.StatusOK || rec == nil {
		writeError(w, http.StatusUnauthorized, "invalid or expired token")
		return nil, nil, false
	}
	return callerFromRecord(rec), rec.Record["pluginSettings"], true
}