package api

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

// Integrations exposes the OpenSky plugin's settings to end users under a
// three-layer cascade (superadmin/global → organization → user). Each of the
// four settings resolves independently, top wins, and a blank field falls
// through to the layer below:
//
//   - global (L1): the plugin's config in plugins.json, set in the API Server panel.
//   - org    (L2): pluginSettings on the caller's organization record (org admins).
//   - user   (L3): pluginSettings on the caller's own user record.
//
// The OAuth2 client id + secret resolve as a *pair* from the highest layer that
// supplies a client id, so credential halves are never mixed across layers.
// Enablement is strictly per-user (L3) and gated by the global master switch.
//
// Secrets (and inherited client ids) 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 (
	openSkyPlugin     = "opensky"
	openSkySecretMask = "••••••••"
)

// osConfig is one layer's OpenSky settings.
type osConfig struct {
	ClientID     string `json:"clientId"`
	ClientSecret string `json:"clientSecret"`
	Plan         string `json:"plan"`
	Bbox         string `json:"bbox"`
}

// osStored is what we persist per user/org under pluginSettings.opensky.
type osStored struct {
	Config osConfig `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: existing org records (which carry a legacy enabled:false
	// from earlier config saves) therefore read as enabled, avoiding a regression.
	// Only meaningful on the org record; ignored on user records.
	Disabled bool `json:"disabled,omitempty"`
}

// osSettingsDoc is the pluginSettings JSON shape (only opensky today).
type osSettingsDoc struct {
	OpenSky osStored `json:"opensky"`
}

// osFieldView is one field's resolved state for the UI.
type osFieldView struct {
	Effective string `json:"effective"` // resolved value in force (secrets/inherited creds masked)
	Own       string `json:"own"`       // the caller's own editable-layer value (secret masked)
	Source    string `json:"source"`    // global | org | user | unset
	Locked    bool   `json:"locked"`    // set above the caller's editable layer
}

// osResolution is the fully-resolved OpenSky state for one caller. It captures the
// effective cascade plus both editable layers (personal + organization), so an org
// admin can manage each independently — their own settings as a user, and the
// organization-wide settings that override every user's.
type osResolution struct {
	eff       osConfig          // effective (unmasked) — used only server-side (probes)
	userOwn   osConfig          // caller's personal (L3) values (unmasked)
	orgOwn    osConfig          // 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
	orgEnabled bool             // org master switch (default true; gates the org's users)
	allowAnon bool              // global anonymous policy
	enabled   bool              // caller's personal enable flag
}

// resolveOpenSky computes the cascade for a caller. userRaw is the caller's
// pluginSettings blob (from their auth-refresh record).
func (s *Server) resolveOpenSky(ctx context.Context, who *callerIdentity, userRaw json.RawMessage) osResolution {
	g, masterEnabled, _ := s.plugins.RawConfig(openSkyPlugin)
	gc := osConfig{ClientID: g["clientId"], ClientSecret: g["clientSecret"], Plan: g["plan"], Bbox: g["bbox"]}
	allowAnon := !strings.EqualFold(strings.TrimSpace(g["allowAnonymous"]), "false")

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

	var uStored osStored
	if len(userRaw) > 0 {
		var d osSettingsDoc
		_ = json.Unmarshal(userRaw, &d)
		uStored = d.OpenSky
	}
	uc := uStored.Config

	res := osResolution{
		source:    map[string]string{},
		userOwn:   uc,
		orgOwn:    oc,
		isSuper:   who.isSuperadmin(),
		// An org admin may edit the organization layer in addition to their own
		// personal layer. Requires the service account (org writes go through it);
		// without it the org layer is invisible to the cascade anyway.
		canOrg:    who.isManager() && !who.isSuperadmin() && who.OrgID != "" && s.admin.configured(),
		available: masterEnabled,
		// Org gate: enabled by default, off only when the org explicitly disabled it.
		orgEnabled: !oStored.Disabled,
		allowAnon:  allowAnon,
		enabled:    uStored.Enabled,
	}

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

	pick := func(get func(osConfig) string) (val, src string) {
		for _, l := range layers {
			if v := strings.TrimSpace(get(l.c)); v != "" {
				return v, l.name
			}
		}
		return "", "unset"
	}
	res.eff.Plan, res.source["plan"] = pick(func(c osConfig) string { return c.Plan })
	res.eff.Bbox, res.source["bbox"] = pick(func(c osConfig) string { return c.Bbox })

	// Credentials resolve as a pair from the highest layer with a client id.
	credSrc := "unset"
	for _, l := range layers {
		if id := strings.TrimSpace(l.c.ClientID); id != "" {
			res.eff.ClientID, res.eff.ClientSecret, credSrc = id, l.c.ClientSecret, l.name
			break
		}
	}
	res.source["clientId"] = credSrc
	res.source["clientSecret"] = credSrc
	return res
}

// layerRank orders the cascade layers; a higher number is lower priority.
var layerRank = map[string]int{"global": 1, "org": 2, "user": 3}

// lockedFor reports whether a field whose value comes from source is locked for a
// caller whose editable layer is editable (i.e. the value is set above them).
func lockedFor(source, editable string) bool {
	if editable == "none" {
		return true // superadmin edits the global layer in the panel, not here
	}
	sr, ok := layerRank[source]
	if !ok {
		return false // unset — the caller may be the first to set it
	}
	return sr < layerRank[editable]
}

// maskPresent returns the secret mask when v is non-empty, else "".
func maskPresent(v string) string {
	if strings.TrimSpace(v) != "" {
		return openSkySecretMask
	}
	return ""
}

// orgOpenSky reads an organization's stored OpenSky settings (config + the org
// gate) and its raw pluginSettings blob via the service account. Best effort: zero
// values on any miss so callers can proceed as if the org layer were empty.
func (s *Server) orgOpenSky(ctx context.Context, orgID string) (osStored, json.RawMessage) {
	if orgID == "" || !s.admin.configured() {
		return osStored{}, 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 osStored{}, nil
	}
	var rec struct {
		PluginSettings json.RawMessage `json:"pluginSettings"`
	}
	_ = json.Unmarshal(data, &rec)
	var doc osSettingsDoc
	if len(rec.PluginSettings) > 0 {
		_ = json.Unmarshal(rec.PluginSettings, &doc)
	}
	return doc.OpenSky, rec.PluginSettings
}

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

// callerFromRecord builds an identity from an auth-refresh record.
func callerFromRecord(rec *pbAuthResp) *callerIdentity {
	role := unquote(rec.Record["role"])
	if role == "" {
		role = roleUser
	}
	return &callerIdentity{
		ID:    unquote(rec.Record["id"]),
		Email: unquote(rec.Record["email"]),
		Role:  role,
		OrgID: unquote(rec.Record["organization"]),
	}
}

// GET /api/integrations/opensky — resolved OpenSky view for the caller.
func (s *Server) handleGetOpenSky(w http.ResponseWriter, r *http.Request) {
	token := r.Header.Get("Authorization")
	if token == "" {
		writeError(w, http.StatusUnauthorized, "missing token")
		return
	}
	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
	}
	if status != http.StatusOK || rec == nil {
		writeError(w, http.StatusUnauthorized, "invalid or expired token")
		return
	}
	who := callerFromRecord(rec)
	res := s.resolveOpenSky(r.Context(), who, rec.Record["pluginSettings"])
	writeJSON(w, http.StatusOK, s.openSkyView(who, res))
}

// osScopeView builds the masked field set for one editable scope. editable is the
// layer the caller edits in this scope ("user" | "org" | "none"); a field is locked
// when its effective value is set above that layer.
func (s *Server) osScopeView(res osResolution, editable string) map[string]any {
	own := res.userOwn
	if editable == "org" {
		own = res.orgOwn
	}
	field := func(key, eff, ownv string, secret bool) osFieldView {
		src := res.source[key]
		locked := lockedFor(src, editable)
		fv := osFieldView{Source: src, Locked: locked}
		switch {
		case secret:
			// Never expose a secret; show only presence.
			fv.Effective, fv.Own = maskPresent(eff), maskPresent(ownv)
		case key == "clientId" && locked:
			// Inherited client id — hide the concrete value from a lower layer.
			fv.Effective, fv.Own = maskPresent(eff), maskPresent(ownv)
		default:
			fv.Effective, fv.Own = eff, ownv
		}
		return fv
	}
	return map[string]any{
		"editableLayer": editable,
		"fields": map[string]osFieldView{
			"clientId":     field("clientId", res.eff.ClientID, own.ClientID, false),
			"clientSecret": field("clientSecret", res.eff.ClientSecret, own.ClientSecret, true),
			"plan":         field("plan", res.eff.Plan, own.Plan, false),
			"bbox":         field("bbox", res.eff.Bbox, own.Bbox, false),
		},
	}
}

// openSkyView builds the masked, client-safe response body from a resolution. It
// exposes a "user" scope for everyone plus, for org admins, an "org" scope — each
// with its own locked-field state — so the UI can present the two independently.
func (s *Server) openSkyView(who *callerIdentity, res osResolution) map[string]any {
	out := map[string]any{
		"available":      res.available,
		"orgEnabled":     res.orgEnabled,
		"allowAnonymous": res.allowAnon,
		"enabled":        res.enabled,
		"role":           who.Role,
		"orgId":          who.OrgID,
		"canEditOrg":     res.canOrg,
		"isSuperadmin":   res.isSuper,
	}
	if res.isSuper {
		// Superadmin manages the global layer in the panel; here it is read-only.
		out["editableLayer"] = "none"
		out["scopes"] = map[string]any{"user": s.osScopeView(res, "none")}
		return out
	}
	scopes := map[string]any{"user": s.osScopeView(res, "user")}
	if res.canOrg {
		scopes["org"] = s.osScopeView(res, "org")
	}
	out["scopes"] = scopes
	return out
}

// PUT /api/integrations/opensky — save the caller's editable layer. Body:
// {enabled?: bool, config?: {clientId, clientSecret, plan, bbox}}. Fields locked
// above the caller are ignored; a client secret left at the mask is preserved.
func (s *Server) handlePutOpenSky(w http.ResponseWriter, r *http.Request) {
	token := r.Header.Get("Authorization")
	if token == "" {
		writeError(w, http.StatusUnauthorized, "missing token")
		return
	}
	var body struct {
		Enabled *bool             `json:"enabled"`
		Scope   string            `json:"scope"` // "user" (default) | "org" (admins only)
		Config  map[string]string `json:"config"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		writeError(w, http.StatusBadRequest, "invalid json")
		return
	}

	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
	}
	if status != http.StatusOK || rec == nil {
		writeError(w, http.StatusUnauthorized, "invalid or expired token")
		return
	}
	who := callerFromRecord(rec)
	userRaw := rec.Record["pluginSettings"]
	res := s.resolveOpenSky(r.Context(), who, userRaw)

	// Resolve which layer this write targets. Everyone edits their own personal
	// (user) layer by default; an org admin may target the organization layer by
	// asking for scope "org". Superadmins are read-only here (they manage global
	// in the panel) and may only toggle their personal enable flag.
	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"
	}

	// Build the new target-layer config from its current own values, overlaying
	// only fields the caller is allowed to change in this scope.
	newOwn := res.userOwn
	if editable == "org" {
		newOwn = res.orgOwn
	}
	applyField := func(key string, set func(*osConfig, string)) {
		v, ok := body.Config[key]
		if !ok || lockedFor(res.source[key], editable) {
			return
		}
		if key == "clientSecret" && v == openSkySecretMask {
			return // keep current secret
		}
		set(&newOwn, strings.TrimSpace(v))
	}
	applyField("plan", func(c *osConfig, v string) { c.Plan = v })
	applyField("bbox", func(c *osConfig, v string) { c.Bbox = v })
	applyField("clientId", func(c *osConfig, v string) { c.ClientID = v })
	// Secret is not trimmed (may legitimately contain edge whitespace? no — trim
	// for consistency with the panel's Upsert, which TrimSpaces all values).
	applyField("clientSecret", func(c *osConfig, v string) { c.ClientSecret = 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.orgOpenSky(r.Context(), who.OrgID)
		newDoc := mergeOpenSky(orgRaw, func(os *osStored) {
			os.Config = newOwn
			// In the org scope the enable flag is the org master switch, stored
			// inverted (disabled) so absent means enabled.
			if body.Enabled != nil {
				os.Disabled = !*body.Enabled
			}
		})
		_, 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 — in the org scope it targets the org gate instead), and so does the
	// personal config layer when this write targets the user scope.
	personalEnable := body.Enabled != nil && editable != "org"
	if personalEnable || editable == "user" {
		newDoc := mergeOpenSky(userRaw, func(os *osStored) {
			if personalEnable {
				os.Enabled = *body.Enabled
			}
			if editable == "user" {
				os.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 {
		// The writes succeeded; just report success minimally.
		writeJSON(w, http.StatusOK, map[string]any{"ok": true})
		return
	}
	res2 := s.resolveOpenSky(r.Context(), who, fresh.Record["pluginSettings"])
	writeJSON(w, http.StatusOK, s.openSkyView(who, res2))
}

// patchUserPluginSettings writes the pluginSettings blob onto the caller's own
// user record using their token (PocketBase authorises self-writes).
func (s *Server) patchUserPluginSettings(ctx context.Context, token, id string, doc json.RawMessage) (int, error) {
	if id == "" {
		return 0, io.EOF // treated as a transport-ish failure by the caller
	}
	patch, _ := json.Marshal(map[string]json.RawMessage{"pluginSettings": doc})
	req, _ := http.NewRequestWithContext(ctx, http.MethodPatch,
		s.auth.url()+"/api/collections/users/records/"+url.PathEscape(id), bytes.NewReader(patch))
	req.Header.Set("Authorization", token)
	req.Header.Set("Content-Type", "application/json")
	resp, err := s.auth.client.Do(req)
	if err != nil {
		return 0, err
	}
	defer resp.Body.Close()
	_, _ = io.Copy(io.Discard, resp.Body)
	return resp.StatusCode, nil
}

// POST /api/integrations/opensky/health — live probe using the caller's resolved
// config. Never returns secrets.
func (s *Server) handleOpenSkyHealth(w http.ResponseWriter, r *http.Request) {
	token := r.Header.Get("Authorization")
	if token == "" {
		writeError(w, http.StatusUnauthorized, "missing token")
		return
	}
	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
	}
	if status != http.StatusOK || rec == nil {
		writeError(w, http.StatusUnauthorized, "invalid or expired token")
		return
	}
	who := callerFromRecord(rec)
	if !who.isSuperadmin() {
		if _, _, ok := s.plugins.RawConfig(openSkyPlugin); !ok {
			writeError(w, http.StatusNotFound, "unknown plugin")
			return
		}
	}
	res := s.resolveOpenSky(r.Context(), who, rec.Record["pluginSettings"])
	if !res.available {
		writeJSON(w, http.StatusOK, map[string]any{"health": map[string]any{
			"status": "down", "detail": "OpenSky is disabled by the administrator"}})
		return
	}
	if !res.orgEnabled {
		writeJSON(w, http.StatusOK, map[string]any{"health": map[string]any{
			"status": "down", "detail": "OpenSky is disabled for your organization"}})
		return
	}
	cfg := map[string]string{
		"clientId":       res.eff.ClientID,
		"clientSecret":   res.eff.ClientSecret,
		"plan":           res.eff.Plan,
		"bbox":           res.eff.Bbox,
		"allowAnonymous": boolStr(res.allowAnon),
	}
	h, err := s.plugins.HealthCheckWith(r.Context(), openSkyPlugin, cfg)
	if err != nil {
		writeJSON(w, http.StatusBadGateway, map[string]any{"error": err.Error()})
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"health": h})
}

func boolStr(b bool) string {
	if b {
		return "true"
	}
	return "false"
}