// Package api exposes the HTTP REST surface of the DriverVault API Server.
//
// Clients (web app, phone app, Home Assistant plugin, ESP32 device) talk only to
// this server; this server is the only thing that talks to PocketBase. It also
// serves the superadmin web panel at the root.
//
// Authentication is PocketBase's own: /api/auth/login is proxied to the
// PocketBase users collection and the client keeps the token PocketBase minted.
// Every protected request re-resolves that token against PocketBase, so a role
// change or a deletion takes effect immediately.
//
//	# public
//	GET    /healthz
//	GET    /api/health
//	GET    /api/status
//	POST   /api/auth/login
//	GET    /api/auth/validate
//
//	# identity
//	GET    /api/auth/me
//	GET    /api/identity
//
//	# current user
//	GET    /api/me                     PATCH  /api/me                DELETE /api/me
//	POST   /api/me/password
//	POST   /api/me/avatar              GET    /api/me/avatar         DELETE /api/me/avatar
//	POST   /api/me/verify/request
//	GET    /api/me/export              POST   /api/me/import
//	POST   /api/me/delete              POST   /api/me/delete/cancel
//
//	# users + organizations (manager; writes to orgs are superadmin-only)
//	GET    /api/users                  POST   /api/users
//	PATCH  /api/users/{id}             DELETE /api/users/{id}
//	GET    /api/orgs                   POST   /api/orgs
//	PATCH  /api/orgs/{id}              DELETE /api/orgs/{id}
//
//	# superadmin
//	GET    /api/admin/pb-config        PUT    /api/admin/pb-config
//	POST   /api/admin/pb-config/test
//	GET    /api/admin/plugins          POST   /api/admin/plugins
//	GET    /api/admin/plugins/{name}   PUT    /api/admin/plugins/{name}
//	DELETE /api/admin/plugins/{name}   POST   /api/admin/plugins/{name}/health
//
//	# cars, service records, parts, shares
//	GET    /api/cars                   POST   /api/cars
//	GET    /api/cars/{id}              PATCH  /api/cars/{id}         DELETE /api/cars/{id}
//	GET    /api/cars/{id}/service-records
//	GET    /api/cars/{id}/parts
//	GET    /api/cars/{id}/shares       POST   /api/cars/{id}/shares
//	DELETE /api/cars/{id}/shares/{userId}
//	GET    /api/service-records        POST   /api/service-records
//	GET    /api/service-records/{id}   PATCH  /api/service-records/{id}
//	DELETE /api/service-records/{id}
//	GET    /api/parts                  POST   /api/parts
//	GET    /api/parts/{id}             PATCH  /api/parts/{id}        DELETE /api/parts/{id}
package api

import (
	"context"
	"log"
	"net/http"
	"sync"
	"time"

	"drivervault/apiserver/internal/config"
	"drivervault/apiserver/internal/pb"
	"drivervault/apiserver/internal/plugins"
	_ "drivervault/apiserver/internal/plugins/builtin" // register built-in plugins
)

// PocketBase collection names.
const (
	colCars     = "cars"
	colServices = "service_records"
	colParts    = "parts"
	colShares   = "car_shares"
	colOrgs     = "organizations"
)

// Server wires together the HTTP handlers and their dependencies.
type Server struct {
	mu      sync.RWMutex // guards the mutable PocketBase connection in cfg
	cfg     config.Config
	pb      *pb.Client
	plugins *plugins.Manager
}

// New constructs a Server around an already-built PocketBase client.
func New(cfg config.Config, client *pb.Client) *Server {
	return &Server{
		cfg:     cfg,
		pb:      client,
		plugins: plugins.NewManager(cfg.PluginsFile),
	}
}

// StartPlugins loads persisted plugin state and initialises enabled plugins.
func (s *Server) StartPlugins() error { return s.plugins.Load() }

// Stop releases server-held resources (currently: plugin instances).
func (s *Server) Stop(ctx context.Context) { s.plugins.Shutdown(ctx) }

// usersCollection returns the PocketBase auth collection holding app users.
func (s *Server) usersCollection() string {
	s.mu.RLock()
	defer s.mu.RUnlock()
	return s.cfg.UsersCollection
}

// webAppURL returns the Web App address probed by /api/status.
func (s *Server) webAppURL() string {
	s.mu.RLock()
	defer s.mu.RUnlock()
	return s.cfg.WebAppURL
}

// pbSettings snapshots the PocketBase connection for the settings endpoints.
func (s *Server) pbSettings() (url, adminEmail, adminPassword string) {
	s.mu.RLock()
	defer s.mu.RUnlock()
	return s.cfg.PocketBaseURL, s.cfg.PocketBaseAdminEmail, s.cfg.PocketBaseAdminPassword
}

// setPBConfig retargets the PocketBase connection at runtime: it updates the
// cached config and repoints the client (which drops its cached superuser token,
// so the next call re-authenticates against the new target).
func (s *Server) setPBConfig(url, adminEmail, adminPassword string) {
	s.mu.Lock()
	s.cfg.PocketBaseURL = url
	s.cfg.PocketBaseAdminEmail = adminEmail
	s.cfg.PocketBaseAdminPassword = adminPassword
	s.mu.Unlock()

	s.pb.Reconfigure(url, adminEmail, adminPassword)
}

// Handler returns the root HTTP handler with all routes registered.
func (s *Server) Handler() http.Handler {
	mux := http.NewServeMux()

	// Web panel (public) — embedded Vue + Tailwind app. Only the explicit panel
	// paths are routed to it so unknown /api/* paths still 404 as JSON.
	panel := panelHandler()
	mux.Handle("GET /{$}", panel)
	mux.Handle("GET /assets/", panel)
	mux.Handle("GET /favicon.svg", panel)

	// Health (public).
	mux.HandleFunc("GET /healthz", s.handleHealth)
	mux.HandleFunc("GET /api/health", s.handleHealth)
	mux.HandleFunc("GET /api/status", s.handleStatus)

	// Auth — proxied to the PocketBase kept behind this server.
	mux.HandleFunc("POST /api/auth/login", s.handleAuthLogin)
	mux.HandleFunc("GET /api/auth/validate", s.handleAuthValidate)
	mux.HandleFunc("GET /api/auth/me", s.handleAuthMe)
	mux.HandleFunc("GET /api/identity", s.handleIdentity)

	// Current user (profile / appearance / avatar / data / account lifecycle).
	mux.HandleFunc("GET /api/me", s.handleGetMe)
	mux.HandleFunc("PATCH /api/me", s.handleUpdateMe)
	mux.HandleFunc("POST /api/me/password", s.handleChangePassword)
	mux.HandleFunc("POST /api/me/avatar", s.handleUploadAvatar)
	mux.HandleFunc("GET /api/me/avatar", s.handleGetAvatar)
	mux.HandleFunc("DELETE /api/me/avatar", s.handleDeleteAvatar)
	mux.HandleFunc("POST /api/me/verify/request", s.handleRequestVerification)
	mux.HandleFunc("GET /api/me/export", s.handleExportData)
	mux.HandleFunc("POST /api/me/import", s.handleImportData)
	mux.HandleFunc("POST /api/me/delete", s.handleRequestDeletion)
	mux.HandleFunc("POST /api/me/delete/cancel", s.handleCancelDeletion)
	mux.HandleFunc("DELETE /api/me", s.handleFinalizeDeletion)

	// User management — gated on the caller being a manager (admin or
	// superadmin). Admins are scoped to their own organization inside each
	// handler.
	mux.HandleFunc("GET /api/users", s.requireManager(s.handleListUsers))
	mux.HandleFunc("POST /api/users", s.requireManager(s.handleCreateUser))
	mux.HandleFunc("PATCH /api/users/{id}", s.requireManager(s.handleUpdateUser))
	mux.HandleFunc("DELETE /api/users/{id}", s.requireManager(s.handleDeleteUser))

	// Organizations — listing is manager-scoped; create/edit/delete are
	// superadmin-only (a superadmin spans all organizations).
	mux.HandleFunc("GET /api/orgs", s.requireManager(s.handleListOrgs))
	mux.HandleFunc("POST /api/orgs", s.requireSuperadmin(s.handleCreateOrg))
	mux.HandleFunc("PATCH /api/orgs/{id}", s.requireSuperadmin(s.handleUpdateOrg))
	mux.HandleFunc("DELETE /api/orgs/{id}", s.requireSuperadmin(s.handleDeleteOrg))

	// PocketBase connection settings — superadmin only. These do NOT require the
	// service account to already be configured (they exist to configure it).
	mux.HandleFunc("GET /api/admin/pb-config", s.requireSuperadminAuth(s.handleGetPBConfig))
	mux.HandleFunc("POST /api/admin/pb-config/test", s.requireSuperadminAuth(s.handleTestPBConfig))
	mux.HandleFunc("PUT /api/admin/pb-config", s.requireSuperadminAuth(s.handleUpdatePBConfig))

	// Plugins — external-service integrations, managed by a superadmin.
	mux.HandleFunc("GET /api/admin/plugins", s.requireSuperadminAuth(s.handleListPlugins))
	mux.HandleFunc("POST /api/admin/plugins", s.requireSuperadminAuth(s.handleRegisterPlugin))
	mux.HandleFunc("GET /api/admin/plugins/{name}", s.requireSuperadminAuth(s.handleGetPlugin))
	mux.HandleFunc("PUT /api/admin/plugins/{name}", s.requireSuperadminAuth(s.handleUpdatePlugin))
	mux.HandleFunc("DELETE /api/admin/plugins/{name}", s.requireSuperadminAuth(s.handleDeletePlugin))
	mux.HandleFunc("POST /api/admin/plugins/{name}/health", s.requireSuperadminAuth(s.handlePluginHealth))

	// Cars + sharing.
	mux.HandleFunc("GET /api/cars", s.listCars)
	mux.HandleFunc("POST /api/cars", s.createCar)
	mux.HandleFunc("GET /api/cars/{id}", s.getCar)
	mux.HandleFunc("PATCH /api/cars/{id}", s.updateCar)
	mux.HandleFunc("DELETE /api/cars/{id}", s.deleteCar)
	mux.HandleFunc("GET /api/cars/{id}/service-records", s.listCarServiceRecords)
	mux.HandleFunc("GET /api/cars/{id}/parts", s.listCarParts)
	mux.HandleFunc("GET /api/cars/{id}/shares", s.handleListShares)
	mux.HandleFunc("POST /api/cars/{id}/shares", s.handleUpsertShare)
	mux.HandleFunc("DELETE /api/cars/{id}/shares/{userId}", s.handleDeleteShare)

	// Service records.
	mux.HandleFunc("GET /api/service-records", s.listServiceRecords)
	mux.HandleFunc("POST /api/service-records", s.createServiceRecord)
	mux.HandleFunc("GET /api/service-records/{id}", s.getServiceRecord)
	mux.HandleFunc("PATCH /api/service-records/{id}", s.updateServiceRecord)
	mux.HandleFunc("DELETE /api/service-records/{id}", s.deleteServiceRecord)

	// Parts.
	mux.HandleFunc("GET /api/parts", s.listParts)
	mux.HandleFunc("POST /api/parts", s.createPart)
	mux.HandleFunc("GET /api/parts/{id}", s.getPart)
	mux.HandleFunc("PATCH /api/parts/{id}", s.updatePart)
	mux.HandleFunc("DELETE /api/parts/{id}", s.deletePart)

	return s.withMiddleware(mux)
}

// withMiddleware applies panic recovery, CORS, request logging, and
// authentication globally.
func (s *Server) withMiddleware(next http.Handler) http.Handler {
	return s.recoverer(s.cors(s.logger(s.withAuth(next))))
}

func (s *Server) logger(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		sw := &statusWriter{ResponseWriter: w, status: http.StatusOK}
		next.ServeHTTP(sw, r)
		log.Printf("%s %s %d %s", r.Method, r.URL.Path, sw.status, time.Since(start).Round(time.Millisecond))
	})
}

func (s *Server) recoverer(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		defer func() {
			if rec := recover(); rec != nil {
				log.Printf("panic: %v", rec)
				writeError(w, http.StatusInternalServerError, "internal error")
			}
		}()
		next.ServeHTTP(w, r)
	})
}

func (s *Server) cors(next http.Handler) http.Handler {
	allowed := map[string]bool{}
	wildcard := false
	for _, o := range s.cfg.AllowOrigins {
		if o == "*" {
			wildcard = true
		}
		allowed[o] = true
	}
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		origin := r.Header.Get("Origin")
		if origin != "" && (wildcard || allowed[origin]) {
			if wildcard {
				w.Header().Set("Access-Control-Allow-Origin", "*")
			} else {
				w.Header().Set("Access-Control-Allow-Origin", origin)
				w.Header().Add("Vary", "Origin")
			}
			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PATCH, DELETE, OPTIONS")
			w.Header().Set("Access-Control-Allow-Headers", "Authorization, Content-Type")
		}
		if r.Method == http.MethodOptions {
			w.WriteHeader(http.StatusNoContent)
			return
		}
		next.ServeHTTP(w, r)
	})
}

// statusWriter captures the response status code for logging.
type statusWriter struct {
	http.ResponseWriter
	status int
	wrote  bool
}

func (w *statusWriter) WriteHeader(code int) {
	if !w.wrote {
		w.status = code
		w.wrote = true
	}
	w.ResponseWriter.WriteHeader(code)
}

func (w *statusWriter) Write(b []byte) (int, error) {
	w.wrote = true
	return w.ResponseWriter.Write(b)
}