import { randomBytes, randomUUID } from "node:crypto";
import type { FastifyInstance } from "fastify";
import { eq, devices, setupState, type Db } from "@parking/db";
import {
  hasPreconditions,
  hasPushConfig,
  isCamera,
  isDiscoverable,
  isHardenable,
  registerBuiltinDrivers,
  registry,
  setDeviceLogSink,
  type CameraDevice,
  type DeviceCategory,
  type DeviceConfig,
} from "@parking/devices";
import { requirePermission } from "../auth.js";
import { backendIpCandidates, backendIpForDevice, backendPort } from "../net.js";
import type { VisionClient } from "../vision-client.js";

// First-run setup API. The admin reads the driver catalog and assigns devices
// per lane. See wiki/concepts/first-run-setup.md.

interface AssignBody {
  category: DeviceCategory;
  driverId: string;
  // Driver config (opaque JSON, validated by the driver). Carries the model's
  // direction/binding: access → config.relays=[{relay,direction,button?}];
  // reader/camera → config.controllerId + config.relay. See entry-exit-points.md.
  config: DeviceConfig;
  /** Optional: the backend IP the device should push to (overrides auto-pick;
   *  matters on multi-NIC hosts). */
  backendIp?: string;
}

interface TestBody {
  driverId: string;
  config: Record<string, string | number | boolean>;
  /** When editing an EXISTING device, its id — so the test re-merges the stored
   *  machine secrets (relayPassword/pushPassword) the client never received. Without
   *  this, testing an edited device would send no relay password → the device ignores
   *  the probe → a false "offline". Omitted when testing a brand-new device. */
  id?: string;
}

// Config keys that hold MACHINE-ONLY secrets — never sent back to the client.
// No human ever uses these to log in: `pushPassword` is the device→backend Digest
// secret, `relayPassword` is the binary-protocol relay_pw. They stay redacted.
//
// NOTE: the device web-UI login (`webUser`/`webPassword`) is deliberately NOT
// redacted. It's an operational credential an admin needs to reach the device's
// own web page, and the whole device-management area is admin-only — so it's
// surfaced in the admin device view rather than hidden. See first-run-setup.md.
const SECRET_CONFIG_KEYS = ["pushPassword", "relayPassword"] as const;

function redactSecrets(config: Record<string, unknown>): Record<string, unknown> {
  const out = { ...config };
  for (const k of SECRET_CONFIG_KEYS) delete out[k];
  return out;
}

// Connection-identity keys: the fields that decide WHERE a probe is sent. A stored
// secret may only be re-merged when these match the stored row — otherwise an admin
// could point a test at an attacker host while keeping a real device id and have the
// secret sent there (exfiltration). host/port/binaryPort/httpPort cover the Dingtian's
// UDP + CGI targets; serial covers serial-bound readers.
const IDENTITY_KEYS = ["host", "port", "binaryPort", "httpPort", "serial"] as const;

/** Stored machine-only secrets (relayPassword/pushPassword) for a device `id`, but ONLY
 *  when the submitted config addresses the SAME device — same driver, and every
 *  connection-identity field (host/port/…) that the submitted config sets equals the
 *  stored value. If the admin redirected the probe (different host/port) or the driver
 *  doesn't match, NO secret is returned: they must re-enter it explicitly. This stops a
 *  redirected test from exfiltrating the secret to an attacker host. */
export function storedSecrets(
  db: Db,
  id: string,
  driverId: string,
  submitted: Record<string, unknown>,
): Record<string, unknown> {
  const row = db.select().from(devices).where(eq(devices.id, id)).get();
  if (!row || row.driverId !== driverId) return {};
  const cfg = row.config as Record<string, unknown>;
  // Any identity field the client SENT must equal the stored value. (A field the client
  // omits falls back to the stored device, so it can't be used to redirect.)
  for (const k of IDENTITY_KEYS) {
    const sent = submitted[k];
    if (sent !== undefined && sent !== "" && String(sent) !== String(cfg[k] ?? "")) {
      return {};
    }
  }
  const out: Record<string, unknown> = {};
  for (const k of SECRET_CONFIG_KEYS) if (cfg[k] !== undefined) out[k] = cfg[k];
  return out;
}

/** Result of the device configure pipeline: a ready-to-persist config, or an
 *  HTTP error to send back. Shared by assign (create) and patch (edit). */
type ConfigureOutcome =
  | { config: Record<string, unknown>; warnings: string[] }
  | { error: { code: number; message: string } };

/**
 * Validate + configure a device, returning the config to persist. Runs the same
 * pipeline for both create and edit: validate the driver config, fix
 * preconditions, harden (relay password + protocol lockdown), and set up input
 * push (Digest creds + push URLs). Each step is a device write (the device
 * reboots on apply). The caller owns the DB row; this never touches the DB.
 *
 * `id` is the assignment id (stable across an edit) — it's baked into the push
 * URL, so editing in place keeps the device pushing to the same path.
 * `existingConfig` carries forward secrets the client never sees on edit
 * (push/relay passwords), so a PATCH that omits them doesn't wipe them.
 */
async function configureDevice(
  app: FastifyInstance,
  args: {
    id: string;
    driverId: string;
    config: DeviceConfig;
    backendIp?: string;
    existingConfig?: Record<string, unknown>;
  },
): Promise<ConfigureOutcome> {
  const { id, driverId, config, backendIp, existingConfig } = args;

  // Start from any machine-only secrets already on the row (push/relay passwords
  // are redacted out of the client's copy, so an edit would otherwise drop them),
  // then layer the submitted config on top.
  const fullConfig: Record<string, unknown> = { ...existingConfig, ...config };
  // The web password the admin typed is a DESIRED value, not a stored fact:
  // it's passed to the driver (via create(config) below) as the rotation
  // target, but we do NOT persist it from the form. Only harden()'s VERIFIED
  // secrets.webPassword gets saved — otherwise a failed rotation would leave
  // the DB claiming a password the device never accepted (login stays old).
  delete fullConfig.webPassword;
  // webPasswordCurrent is an input-only credential (the OLD password used to
  // authorize the change) — never persist it as typed.
  delete fullConfig.webPasswordCurrent;
  // Residual-risk warnings from device hardening (shown to the admin; the
  // save still succeeds — these are "configured, but note X" advisories).
  const hardenWarnings: string[] = [];

  let device;
  try {
    device = registry.create(driverId, config); // validates required fields
  } catch (err) {
    return { error: { code: 400, message: (err as Error).message } };
  }

  // Configure the device on save (before persisting, so we don't store a row
  // for a device we couldn't configure):
  //   1. fix preconditions (e.g. disable input_link_relay so a button press
  //      doesn't auto-fire its relay — host must decide first),
  //   2. harden (relay password + disable unused protocol channels), and
  //   3. set up input push (Digest creds + push URLs).
  // Each step is a device config write (the device reboots on apply).
  try {
    if (hasPreconditions(device)) {
      const fixed = await device.fixPreconditions();
      if (!fixed.ok) {
        const unfixable = fixed.issues.find((i) => !i.fixable);
        return {
          error: {
            code: 502,
            message: `device precondition not satisfied: ${unfixable?.message ?? fixed.issues[0]?.message}`,
          },
        };
      }
    }

    if (isHardenable(device)) {
      const { secrets, warnings } = await device.harden();
      Object.assign(fullConfig, secrets); // e.g. relayPassword
      // Surface residual-risk warnings (e.g. firmware that won't disable the
      // password-less string protocol) so the admin can act (web-UI step).
      for (const w of warnings ?? []) {
        app.log.warn(`harden(${driverId} ${id}): ${w}`);
        hardenWarnings.push(w);
      }
    }

    if (hasPushConfig(device)) {
      const host = String(config.host ?? "");
      // Admin-provided backend IP wins; else auto-derive (on-subnet NIC).
      const pushHost = backendIp ?? backendIpForDevice(host);
      if (!pushHost) {
        return {
          error: {
            code: 400,
            message: `cannot determine the backend IP on the device's subnet (${host}). Pick one in setup or set BACKEND_HOST_IP.`,
          },
        };
      }
      const pushUser = "dingtian";
      // 24 hex chars = 96 bits. The Dingtian `pass` field caps at 31 chars
      // (longer is silently truncated → auth mismatch), so keep it short.
      const pushPassword = randomBytes(12).toString("hex");
      await device.configureInputPush({
        host: pushHost,
        port: backendPort(),
        pathBase: `/api/devices/${driverId}/${id}/input`,
        auth: { user: pushUser, password: pushPassword },
      });
      fullConfig.pushUser = pushUser;
      fullConfig.pushPassword = pushPassword;
      // Record the backend IP the device was told to push to — lets us detect
      // a later mismatch if the host's IP changes.
      fullConfig.backendIp = pushHost;
    }
  } catch (err) {
    return { error: { code: 502, message: `device configuration failed: ${(err as Error).message}` } };
  }

  return { config: fullConfig, warnings: hardenWarnings };
}

export async function setupRoutes(
  app: FastifyInstance,
  db: Db,
  vision?: VisionClient | null,
): Promise<void> {
  registerBuiltinDrivers();
  setDeviceLogSink((line) => app.log.info(line));

  // Device setup is site administration — it changes which hardware the site runs
  // and how readers bind to relays. Gated on site:update. See ../auth.ts.
  const adminGuard = requirePermission("site:update");

  // Catalog of selectable drivers per category (no secrets — schema only).
  // `discoverable` flags drivers that can scan the LAN; `pushCapable` flags
  // drivers that push to the backend (and thus need a backend IP at assign time).
  app.get("/api/setup/catalog", async () => {
    const catalog = registry.catalog();
    const discoverable = registry.list().filter(isDiscoverable).map((d) => d.id);
    const pushCapable = registry.pushCapable();
    return { ...catalog, discoverable, pushCapable };
  });

  // Scan the LAN for devices a driver can discover (UDP broadcast, etc).
  // Each found device is health-checked so the admin sees reachability before
  // assigning. Admin-only. See wiki/concepts/device-discovery.md.
  app.get<{ Params: { driverId: string } }>(
    "/api/setup/discover/:driverId",
    { preHandler: adminGuard },
    async (req, reply) => {
      const driver = registry.get(req.params.driverId);
      if (!driver) return reply.code(404).send({ error: `unknown driver: ${req.params.driverId}` });
      if (!isDiscoverable(driver)) {
        return reply.code(400).send({ error: `driver ${driver.id} does not support discovery` });
      }
      try {
        const found = await driver.discover();
        const withHealth = await Promise.all(
          found.map(async (d) => {
            let health: { status: string; detail?: string };
            try {
              health = await driver.create(d.config).healthCheck();
            } catch (err) {
              health = { status: "offline", detail: (err as Error).message };
            }
            return { ...d, health };
          }),
        );
        return { driverId: driver.id, devices: withHealth };
      } catch (err) {
        return reply.code(502).send({ error: `discovery failed: ${(err as Error).message}` });
      }
    },
  );

  // Current setup status + assignments. Secrets are stripped from each config
  // (the UI lists devices; it never needs the stored push/relay/web passwords).
  app.get(
    "/api/setup/state",
    { preHandler: adminGuard },
    async () => {
      const state = await db.select().from(setupState).where(eq(setupState.id, 1)).get();
      const rows = await db.select().from(devices).all();
      const assignments = rows.map((r) => ({ ...r, config: redactSecrets(r.config) }));
      return { completedAt: state?.completedAt ?? null, assignments };
    },
  );

  // Test a device config WITHOUT saving or changing the device: validate the
  // config, probe reachability (healthCheck), and report preconditions
  // (e.g. input_link_relay state). Lets the admin verify before committing.
  app.post<{ Body: TestBody }>(
    "/api/setup/test",
    { preHandler: adminGuard },
    async (req, reply) => {
      const { driverId, config, id } = req.body;
      const driver = registry.get(driverId);
      if (!driver) return reply.code(400).send({ error: `unknown driver: ${driverId}` });

      // When editing an existing device, re-merge its stored machine secrets (e.g.
      // relayPassword) — redacted from the client, so the submitted config omits them.
      // Submitted values win (an admin can override), but a blank/0 field falls back to
      // the stored secret so the probe authenticates. Without this, an edited Dingtian
      // tests with no relay password → false "offline". The submitted-value-wins rule:
      // only fill a secret from the store when the form didn't send a real one.
      // Re-merge stored secrets ONLY when this addresses the same device at the same
      // host/port (storedSecrets enforces identity) — so a redirected probe can't leak
      // the secret to an attacker host. Submitted values still win.
      const merged: Record<string, string | number | boolean | undefined> = { ...config };
      if (id) {
        for (const [k, v] of Object.entries(storedSecrets(db, id, driverId, config))) {
          const sent = merged[k];
          if (sent === undefined || sent === "" || sent === 0) merged[k] = v as string | number;
        }
      }

      let device;
      try {
        device = registry.create(driverId, merged as Record<string, string | number | boolean>);
      } catch (err) {
        return reply.code(400).send({ error: (err as Error).message });
      }

      const health = await device.healthCheck();
      const preconditions = hasPreconditions(device)
        ? await device.checkPreconditions()
        : { ok: true, issues: [] };
      return { health, preconditions };
    },
  );

  // Test ANPR end-to-end on a camera config WITHOUT saving: capture a live snapshot
  // off the camera and run it through the vision (ANPR) service, reporting whether a
  // plate was extracted, the read, and how long it took. Lets the admin verify the
  // camera→vision pipeline before committing the camera's `anpr` opt-in. Advisory +
  // fail-soft, exactly like the runtime path (snapshot.ts): a vision failure is a
  // reported "no plate", never a 500. See wiki/entities/opencv-anpr-service.md.
  app.post<{ Body: TestBody }>(
    "/api/setup/test-anpr",
    { preHandler: adminGuard },
    async (req, reply) => {
      const { driverId, config } = req.body;
      const driver = registry.get(driverId);
      if (!driver) return reply.code(400).send({ error: `unknown driver: ${driverId}` });
      if (driver.category !== "camera") {
        return reply.code(400).send({ error: `driver ${driverId} is not a camera` });
      }
      if (!vision?.enabled) {
        // The vision service is off (VISION_ENABLED unset) — there's nothing to test
        // against. Report it cleanly so the UI can say "enable vision first".
        return reply.send({ ok: false, reason: "vision-disabled" });
      }

      let device;
      try {
        device = registry.create(driverId, config);
      } catch (err) {
        return reply.code(400).send({ error: (err as Error).message });
      }
      if (!isCamera(device)) {
        return reply.code(400).send({ error: `driver ${driverId} cannot capture snapshots` });
      }

      // 1) Grab a frame off the camera. A camera/network failure here is the failure
      //    we're testing for — report it, don't 500.
      const startedAt = Date.now();
      let shot: Awaited<ReturnType<CameraDevice["captureSnapshot"]>>;
      try {
        shot = await device.captureSnapshot({ direction: "entry" });
      } catch (err) {
        return reply.send({
          ok: false,
          reason: "snapshot-failed",
          detail: (err as Error).message,
          tookMs: Date.now() - startedAt,
        });
      }

      // 2) Run the same advisory analyze the runtime path uses. `analyze` is fail-soft
      //    (null on any error/timeout) and applies the confidence floor.
      const result = await vision.analyze(shot.bytes, shot.contentType);
      const tookMs = Date.now() - startedAt;
      if (!result || !result.plate) {
        return reply.send({ ok: false, reason: "no-plate", tookMs });
      }
      return reply.send({
        ok: true,
        plate: result.plate.text.trim().toUpperCase(),
        confidence: result.plate.confidence,
        region: result.plate.region ?? null,
        lowConfidence: result.lowConfidence,
        modelVersion: result.modelVersion,
        tookMs,
      });
    },
  );

  // Candidate backend IPs the device can push to, for a given device host. The
  // wizard pre-fills with the on-subnet one and lets the admin override (matters
  // on multi-NIC hosts). See net.ts / wiki/concepts/device-input-flow.md.
  app.get<{ Querystring: { host?: string } }>(
    "/api/setup/backend-ips",
    { preHandler: adminGuard },
    async (req) => {
      const candidates = backendIpCandidates(req.query.host ?? "");
      return { candidates, port: backendPort() };
    },
  );

  // Assign a device. Validates the chosen driver + config, configures the device
  // (fix preconditions + set up Digest-authenticated input push — no manual device-
  // web-UI step by the admin), then persists. Fails the save if the device can't be
  // configured. See wiki/concepts/device-input-flow.md, entry-exit-points.md.
  app.post<{ Body: AssignBody }>(
    "/api/setup/assign",
    { preHandler: adminGuard },
    async (req, reply) => {
      const { category, driverId, config, backendIp } = req.body;
      const driver = registry.get(driverId);
      if (!driver || driver.category !== category) {
        return reply.code(400).send({ error: `invalid driver for ${category}: ${driverId}` });
      }

      const id = randomUUID();
      const outcome = await configureDevice(app, { id, driverId, config, backendIp });
      if ("error" in outcome) {
        return reply.code(outcome.error.code).send({ error: outcome.error.message });
      }

      const row = {
        id,
        category,
        driverId,
        config: outcome.config,
        enabled: true,
      };
      await db.insert(devices).values(row);
      // Don't echo device secrets back (push Digest password, web-UI login, …).
      return reply.code(201).send({
        ...row,
        config: redactSecrets(outcome.config),
        ...(outcome.warnings.length ? { warnings: outcome.warnings } : {}),
      });
    },
  );

  // Edit an assigned device in place. Same configure pipeline as assign, but it
  // UPDATEs the existing row and KEEPS the id — which matters for controllers,
  // since the id is baked into the device's input-push URL
  // (/api/devices/:driverId/:id/input). Delete+re-add would mint a new id and
  // break push until reconfigured; PATCH re-runs harden/push against the same id.
  // The category and driver are fixed at create time (an edit can't change what
  // KIND of device a slot is); only config changes. Admin-only.
  app.patch<{ Params: { id: string }; Body: Omit<AssignBody, "category" | "driverId"> }>(
    "/api/setup/assign/:id",
    { preHandler: adminGuard },
    async (req, reply) => {
      const existing = await db
        .select()
        .from(devices)
        .where(eq(devices.id, req.params.id))
        .get();
      if (!existing) return reply.code(404).send({ error: "no such device assignment" });

      const { config, backendIp } = req.body;
      const outcome = await configureDevice(app, {
        id: existing.id,
        driverId: existing.driverId,
        config,
        backendIp,
        // Carry forward machine-only secrets the client never received, so an
        // edit that omits them doesn't blank out push/relay passwords.
        existingConfig: existing.config,
      });
      if ("error" in outcome) {
        return reply.code(outcome.error.code).send({ error: outcome.error.message });
      }

      await db.update(devices).set({ config: outcome.config }).where(eq(devices.id, existing.id));
      app.log.info(`reconfigured device ${existing.id} (${existing.category}/${existing.driverId})`);
      return reply.code(200).send({
        id: existing.id,
        category: existing.category,
        driverId: existing.driverId,
        config: redactSecrets(outcome.config),
        enabled: existing.enabled,
        ...(outcome.warnings.length ? { warnings: outcome.warnings } : {}),
      });
    },
  );

  // Unassign (remove) a device instance. The schema is multi-instance — one row
  // per (lane, category, instance) — so removing one is just deleting its row by
  // id. Lets the admin manage a LIST of devices per category (add/remove), not a
  // fixed one-per-category slot. Admin-only. See wiki/concepts/first-run-setup.md.
  //
  // NOTE: we only drop our row; we do NOT un-harden / un-configure the device
  // itself (e.g. clear the Dingtian push URL). The device keeps its last config
  // harmlessly — pushes from an unknown device id are already rejected (see
  // routes/devices.ts), and re-assigning reconfigures it. A future "factory
  // reset on unassign" can hook here if needed.
  app.delete<{ Params: { id: string } }>(
    "/api/setup/assign/:id",
    { preHandler: adminGuard },
    async (req, reply) => {
      const existing = await db
        .select()
        .from(devices)
        .where(eq(devices.id, req.params.id))
        .get();
      if (!existing) return reply.code(404).send({ error: "no such device assignment" });
      await db.delete(devices).where(eq(devices.id, req.params.id));
      app.log.info(`unassigned device ${req.params.id} (${existing.category}/${existing.driverId})`);
      return reply.code(204).send();
    },
  );

  // Mark first-run setup complete.
  app.post(
    "/api/setup/complete",
    { preHandler: adminGuard },
    async () => {
      const completedAt = new Date().toISOString();
      await db
        .insert(setupState)
        .values({ id: 1, completedAt })
        .onConflictDoUpdate({ target: setupState.id, set: { completedAt } });
      return { completedAt };
    },
  );
}