package api

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

// This file exposes the "webdav" 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). It mirrors integrations_filetransfer.go — a
// WebDAV endpoint is likewise a connection that is only meaningful as a whole.
//
//   - global (L1): the plugin's config in plugins.json, set in the API Server panel.
//   - org    (L2): pluginSettings.webdav on the caller's organization record.
//   - user   (L3): pluginSettings.webdav on the caller's own user record.
//
// Every connection field (server URL, username, password, TLS verification)
// resolves as a *group* from the highest layer that supplies a server URL, so
// credential halves are never mixed across layers — exactly like filetransfer's
// host-group and OpenSky's client id + secret pair. 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 webDavPlugin = "webdav"

// wdConfig is one layer's webdav settings. Values are strings to match the
// plugin's ConfigField keys 1:1 (they are handed straight to plugins.Init).
type wdConfig struct {
	BaseURL            string `json:"baseURL"`
	Username           string `json:"username"`
	Password           string `json:"password"`
	InsecureSkipVerify string `json:"insecureSkipVerify"`
	BasePath           string `json:"basePath"`
}

// wdConnKeys are the fields that resolve together as one connection (everything
// server-specific). basePath is deliberately excluded — it cascades on its own.
var wdConnKeys = []string{"baseURL", "username", "password", "insecureSkipVerify"}

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

// wdStored is what we persist per user/org under pluginSettings.webdav.
type wdStored struct {
	Config wdConfig `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"`
}

// wdSettingsDoc is the webdav slice of the shared pluginSettings JSON.
type wdSettingsDoc struct {
	WebDav wdStored `json:"webdav"`
}

// wdResolution is the fully-resolved webdav state for one caller.
type wdResolution struct {
	eff        wdConfig          // effective (unmasked) — used only server-side (probes)
	userOwn    wdConfig          // caller's personal (L3) values (unmasked)
	orgOwn     wdConfig          // 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
}

// wdConfigFromMap builds a wdConfig from a flat string map (global plugin config).
func wdConfigFromMap(m map[string]string) wdConfig {
	return wdConfig{
		BaseURL:            m["baseURL"],
		Username:           m["username"],
		Password:           m["password"],
		InsecureSkipVerify: m["insecureSkipVerify"],
		BasePath:           m["basePath"],
	}
}

// wdGet returns a config field by the plugin's key name.
func wdGet(c wdConfig, key string) string {
	switch key {
	case "baseURL":
		return c.BaseURL
	case "username":
		return c.Username
	case "password":
		return c.Password
	case "insecureSkipVerify":
		return c.InsecureSkipVerify
	case "basePath":
		return c.BasePath
	}
	return ""
}

// wdSet writes a config field by the plugin's key name.
func wdSet(c *wdConfig, key, v string) {
	switch key {
	case "baseURL":
		c.BaseURL = v
	case "username":
		c.Username = v
	case "password":
		c.Password = v
	case "insecureSkipVerify":
		c.InsecureSkipVerify = v
	case "basePath":
		c.BasePath = v
	}
}

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

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

	var uStored wdStored
	if len(userRaw) > 0 {
		var d wdSettingsDoc
		_ = json.Unmarshal(userRaw, &d)
		uStored = d.WebDav
	}
	uc := uStored.Config

	res := wdResolution{
		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    wdConfig
	}
	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 server URL, so credential halves are never mixed across layers.
	connSrc := "unset"
	for _, l := range layers {
		if strings.TrimSpace(l.c.BaseURL) != "" {
			for _, k := range wdConnKeys {
				wdSet(&res.eff, k, wdGet(l.c, k))
			}
			connSrc = l.name
			break
		}
	}
	for _, k := range wdConnKeys {
		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
}

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

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

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

// wdScopeView 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) wdScopeView(res wdResolution, editable string) map[string]any {
	own := res.userOwn
	if editable == "org" {
		own = res.orgOwn
	}
	fields := map[string]osFieldView{}
	for _, key := range append(append([]string{}, wdConnKeys...), "basePath") {
		src := res.source[key]
		fv := osFieldView{Source: src, Locked: lockedFor(src, editable)}
		if wdSecretKeys[key] {
			fv.Effective, fv.Own = maskPresent(wdGet(res.eff, key)), maskPresent(wdGet(own, key))
		} else {
			fv.Effective, fv.Own = wdGet(res.eff, key), wdGet(own, key)
		}
		fields[key] = fv
	}
	return map[string]any{"editableLayer": editable, "fields": fields}
}

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

// PUT /api/integrations/webdav — 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) handlePutWebDav(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.resolveWebDav(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{}, wdConnKeys...), "basePath") {
		v, present := body.Config[key]
		if !present || lockedFor(res.source[key], editable) {
			continue
		}
		if wdSecretKeys[key] && v == openSkySecretMask {
			continue // keep current secret
		}
		wdSet(&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.orgWebDav(r.Context(), who.OrgID)
		newDoc := mergeWebDav(orgRaw, func(wd *wdStored) {
			wd.Config = newOwn
			if body.Enabled != nil {
				wd.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 := mergeWebDav(userRaw, func(wd *wdStored) {
			if personalEnable {
				wd.Enabled = *body.Enabled
			}
			if editable == "user" {
				wd.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.resolveWebDav(r.Context(), who, fresh.Record["pluginSettings"])
	writeJSON(w, http.StatusOK, s.webDavView(who, res2))
}

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