/**
 * Shared profile-update logic. The web client hits `/api/auth/profile` PUT
 * and the iOS client hits `/api/user/profile` PATCH — both funnel through
 * `applyProfileUpdate` so we don't fork the validation/audit path.
 */
import { prisma } from "@/lib/db";
import { auditLog } from "@/lib/auth/audit";
import { profileSchema } from "@/lib/validations/auth";
import { isValidTimezone } from "@/lib/tz/format";
import { encrypt } from "@/lib/crypto";
import {
  invalidateUserMedications,
  invalidateUserProfile,
} from "@/lib/cache/invalidate";
import { sanitiseZodIssues, type SanitisedZodIssue } from "@/lib/api-response";
import { checkProfileEmailRateLimit } from "@/lib/rate-limit";
import { annotate } from "@/lib/logging/context";
import { z } from "zod/v4";
import {
  REPROOF_FAILED_CODE,
  REPROOF_REQUIRED_CODE,
  type SensitiveChangeProof,
} from "@/lib/auth/existing-factor-proof";

const extendedProfileSchema = profileSchema.extend({
  displayName: z.string().min(1).max(80).nullable().optional(),
  locale: z
    .enum(["de", "en"], {
      error: "Locale must be de or en.",
    })
    .nullable()
    .optional(),
  timezone: z
    .string()
    .min(1)
    .max(64)
    .refine(isValidTimezone, "Invalid IANA timezone")
    .optional(),
  moodReminderEnabled: z.boolean().optional(),
  // Hour-cycle display preference. AUTO follows the locale convention,
  // H12 forces AM/PM, H24 forces 24-hour.
  timeFormat: z
    .enum(["AUTO", "H12", "H24"], {
      error: "Time format must be AUTO, H12 or H24.",
    })
    .optional(),
  // Date-order display preference. AUTO follows the locale convention,
  // DMY pins day-month-year, MDY month-day-year, YMD ISO yyyy-MM-dd.
  dateFormat: z
    .enum(["AUTO", "DMY", "MDY", "YMD"], {
      error: "Date format must be AUTO, DMY, MDY or YMD.",
    })
    .optional(),
});

type ExtendedProfileInput = z.infer<typeof extendedProfileSchema>;

/**
 * A new email address on an account with a second factor, without that
 * factor proved in the last five minutes. The client answers it with the
 * re-proof dialog (second factor or passkey) and saves again.
 */
export const EMAIL_SECOND_FACTOR_REQUIRED_CODE =
  "profile.update.emailSecondFactorRequired";

/**
 * The only profile fields a demo instance may write: the three the setup
 * flow's baseline step collects.
 *
 * `PUT /api/auth/profile` sits on the proxy's `DEMO_MUTATION_ALLOWLIST` so
 * that step can complete. That list is an EDGE control — it admits a path and
 * a method, and it cannot see that the handler behind the path also writes
 * this account's contact email, its display name, its full name and its
 * insurer fields. On an ordinary instance those are the caller's own record;
 * on the demo, which is ONE published account every visitor signs into, each
 * of them is the record the next visitor arrives at, until a reseed.
 *
 * So the narrowing is here and not in the client. The web form sends only
 * these three plus a display name, but a form is not a control: the whole
 * reason the allowlist exists is that the caller is not trusted.
 */
export const DEMO_WRITABLE_PROFILE_FIELDS = [
  "heightCm",
  "dateOfBirth",
  "gender",
] as const;

/**
 * The profile schema has no cross-field `.refine()` — every field is an
 * independent scalar column. That means a rejected `gender` has no
 * bearing on whether `heightCm` is safe to write, so a single bad field
 * no longer has to take every sibling change down with it (the report:
 * "editing height and gender together lost both").
 *
 * Re-validates each key present in `body` against its own field schema
 * (`extendedProfileSchema.shape[key]`), independent of the others.
 * Fields that pass land in `valid`; fields that fail land in `issues`
 * with `path` set to the field name (a field-level `safeParse` reports
 * an empty path, since it never saw the parent object). Unknown keys
 * are silently dropped, matching `z.object`'s own default behaviour.
 */
function splitValidProfileFields(body: Record<string, unknown>): {
  valid: Partial<ExtendedProfileInput>;
  issues: SanitisedZodIssue[];
} {
  const shape = extendedProfileSchema.shape as Record<string, z.ZodTypeAny>;
  const valid: Record<string, unknown> = {};
  const issues: SanitisedZodIssue[] = [];
  for (const key of Object.keys(body)) {
    const fieldSchema = shape[key];
    if (!fieldSchema) continue;
    const result = fieldSchema.safeParse(body[key]);
    if (result.success) {
      valid[key] = result.data;
    } else {
      for (const issue of result.error.issues) {
        issues.push({ path: key, code: issue.code, message: issue.message });
      }
    }
  }
  return { valid: valid as Partial<ExtendedProfileInput>, issues };
}

export interface ApplyProfileResult {
  ok: true;
  user: {
    id: string;
    username: string;
    displayName: string | null;
    email: string | null;
    role: string;
    heightCm: number | null;
    dateOfBirth: Date | null;
    gender: string | null;
    timezone: string;
    locale: string | null;
    timeFormat: "AUTO" | "H12" | "H24";
    dateFormat: "AUTO" | "DMY" | "MDY" | "YMD";
    moodReminderEnabled: boolean;
    // v1.7.0 — patient-identity fields. `insuranceNumber` is returned in
    // plaintext (decrypted on read by the route) so the client can render
    // the value back into the form; the route is responsible for the read
    // decryption. Here we only echo the two plaintext columns and a
    // boolean presence flag for the encrypted KVNR.
    fullName: string | null;
    insurerName: string | null;
    insurerIkNumber: string | null;
    hasInsuranceNumber: boolean;
  };
  /**
   * Present only when the caller sent at least one invalid field
   * alongside at least one valid one. The fields named here were NOT
   * written — everything absent from this list landed. Empty/undefined
   * means every touched field saved cleanly. The web client resolves
   * `path` against its own field labels to name the rejected field(s);
   * the message stays machine-readable, never shown verbatim.
   */
  rejectedFields?: SanitisedZodIssue[];
}

export interface ApplyProfileError {
  ok: false;
  status: number;
  /**
   * A sentence safe for a person to read — never a raw Zod message (no
   * enum literals, no validator prose). Native/non-i18n callers that
   * ignore `errorCode` still get something a person can act on.
   */
  message: string;
  /**
   * Stable code the web client resolves through `apiErrors.<errorCode>`
   * for a localized sentence (see `localizedApiError`). Absent for
   * non-validation failures (e.g. the 409 email-conflict below) that
   * already carry a safe, specific message.
   */
  errorCode?: string;
  /**
   * Full per-field detail, relocated (not deleted) from the top-level
   * `message`. Matches the `details.issues` multi-issue envelope the
   * iOS contract already expects from other write routes.
   */
  issues?: SanitisedZodIssue[];
}

/**
 * Validate and persist profile updates for `userId`. Returns either an
 * `ApplyProfileResult` on success or `ApplyProfileError` with a status
 * code so callers can shape the wire response themselves.
 *
 * The profile schema has no cross-field dependency, so an invalid field
 * never has to block its valid siblings: a full-object parse is tried
 * first (the common case), and only on failure does the update fall
 * back to `splitValidProfileFields` to salvage whatever validated. If
 * NOTHING in the payload validates, nothing is written — an honest
 * all-or-nothing rejection naming the field that blocked it, rather
 * than a raw validator string.
 */
export async function applyProfileUpdate(
  userId: string,
  body: unknown,
  ipAddress: string | null | undefined,
  opts: {
    /**
     * Decides whether this request may move the account to a NEW email
     * address. The address is what single sign-on links an existing account
     * by, so changing it asks for a fresh proof (`authorizeSensitiveChange`).
     * Receives the `currentPassword` the body carried, if any; the password is
     * never written anywhere.
     */
    authorizeEmailChange: (
      currentPassword: string | null,
    ) => Promise<SensitiveChangeProof>;
  },
): Promise<ApplyProfileResult | ApplyProfileError> {
  const parsed = extendedProfileSchema.safeParse(body);

  let data: Partial<ExtendedProfileInput>;
  let rejectedFields: SanitisedZodIssue[] = [];

  if (parsed.success) {
    data = parsed.data;
  } else {
    if (typeof body !== "object" || body === null || Array.isArray(body)) {
      return {
        ok: false,
        status: 422,
        message: "Nothing was saved. The profile update was not an object.",
        errorCode: "profile.update.invalidBody",
        issues: sanitiseZodIssues(parsed.error.issues),
      };
    }

    const split = splitValidProfileFields(body as Record<string, unknown>);
    data = split.valid;
    rejectedFields = split.issues;

    if (Object.keys(data).length === 0) {
      // Every touched field failed — there is nothing to salvage.
      // Name the field that blocked it so the person fixes one thing
      // instead of re-entering everything.
      const first = rejectedFields[0];
      return {
        ok: false,
        status: 422,
        message: first
          ? `Nothing was saved. Fix the "${first.path}" field and try again.`
          : "Nothing was saved. The submitted profile data was invalid.",
        errorCode: "profile.update.nothingSaved",
        issues: rejectedFields,
      };
    }
  }

  // Ahead of the conflict check below, deliberately: that check answers 409
  // when another account holds the address, which on a public demo is an
  // existence oracle over the instance's accounts. Dropping the field first
  // closes the write and the question in one move.
  if (process.env.DEMO_MODE === "true") {
    const writable = DEMO_WRITABLE_PROFILE_FIELDS as readonly string[];
    data = Object.fromEntries(
      Object.entries(data).filter(([key]) => writable.includes(key)),
    ) as Partial<ExtendedProfileInput>;
  }

  const normalizedEmail = data.email ? data.email.trim().toLowerCase() : null;

  if (data.email !== undefined && normalizedEmail) {
    // A settings form re-posts the whole profile, so the address arrives
    // with every save whether or not it changed. Those saves ask nothing
    // about anyone else's account — the address on file already belongs to
    // this caller — so they skip both the uniqueness probe and the budget.
    // Charging them would spend an honest afternoon of edits on the
    // ceiling and lock the account out of its own settings page.
    //
    // The stored side is normalised for the comparison too. Registration
    // writes the address exactly as typed, so an account registered as
    // `MixedCase@Example.com` would otherwise fail to match its own address
    // and pay for its first ordinary save.
    const current = await prisma.user.findUnique({
      where: { id: userId },
      select: { email: true },
    });
    const addressOnFile = current?.email?.trim().toLowerCase() ?? null;

    if (addressOnFile !== normalizedEmail) {
      // Asked before the uniqueness probe and before the budget: a caller who
      // cannot show it is the account owner learns nothing about which
      // addresses exist here and spends nothing.
      const rawPassword =
        typeof body === "object" && body !== null && !Array.isArray(body)
          ? (body as Record<string, unknown>).currentPassword
          : undefined;
      const currentPassword =
        typeof rawPassword === "string" &&
        rawPassword.length > 0 &&
        rawPassword.length <= 512
          ? rawPassword
          : null;
      const proof = await opts.authorizeEmailChange(currentPassword);
      if (proof !== "ok") {
        annotate({
          action: { name: "profile.email.reproof_refused" },
          meta: { proof },
        });
        const code =
          proof === "rate_limited"
            ? "rate_limited"
            : proof === "failed"
              ? "reproof_failed"
              : proof === "second_factor_required"
                ? "second_factor_required"
                : "reproof_required";
        // Same narrowing as the email budget below: the address is dropped,
        // the rest of the save lands, and `rejectedFields` says why.
        const { email: _unproven, ...keepable } = data;
        if (Object.keys(keepable).length === 0) {
          return {
            ok: false,
            status: proof === "rate_limited" ? 429 : 401,
            message:
              proof === "failed"
                ? "Verification failed"
                : proof === "rate_limited"
                  ? "Too many attempts. Please wait 15 minutes."
                  : proof === "second_factor_required"
                    ? "Confirm with your second factor or a passkey to change the email address."
                    : "Confirm your current password to change the email address.",
            errorCode:
              proof === "failed"
                ? REPROOF_FAILED_CODE
                : proof === "rate_limited"
                  ? "profile.update.emailRateLimited"
                  : proof === "second_factor_required"
                    ? EMAIL_SECOND_FACTOR_REQUIRED_CODE
                    : REPROOF_REQUIRED_CODE,
          };
        }
        data = keepable;
        rejectedFields = [
          ...rejectedFields,
          {
            path: "email",
            code,
            message:
              proof === "second_factor_required"
                ? "Confirm with your second factor or a passkey to change the email address."
                : "Confirm your current password to change the email address.",
          },
        ];
      }
    }

    if (data.email !== undefined && addressOnFile !== normalizedEmail) {
      // Charged BEFORE the probe, not after: a refused request must not
      // learn the answer it was refused for. The 409 below tells any
      // signed-in caller whether an address is registered here, and until
      // this bucket existed neither route that reaches it had a ceiling of
      // any kind — `apiHandler` supplies no default.
      const rl = await checkProfileEmailRateLimit(userId);
      if (!rl.allowed) {
        annotate({ action: { name: "profile.email.throttled" } });
        await auditLog("profile.email.rate_limited", {
          userId,
          ipAddress: ipAddress ?? null,
        });

        // Narrow the refusal to the field, the way the demo narrowing above
        // does: the web form posts the whole profile in one request, so
        // failing all of it would stop somebody setting their timezone for
        // an hour and tell them it was about email addresses. The address is
        // dropped, everything else is saved, and `rejectedFields` says which
        // field did not go through.
        const { email: _refusedAddress, ...keepable } = data;
        if (Object.keys(keepable).length > 0) {
          data = keepable;
          rejectedFields = [
            ...rejectedFields,
            {
              path: "email",
              code: "rate_limited",
              message: "Too many email-address changes.",
            },
          ];
        } else {
          // Nothing else was asked for, so there is nothing to salvage and a
          // partial success would be a lie — the same rule the all-fields-
          // rejected 422 above follows. This is the arm the published 429
          // describes.
          return {
            ok: false,
            status: 429,
            message: "Too many email-address changes. Try again later.",
            errorCode: "profile.update.emailRateLimited",
          };
        }
      } else {
        // Case-sensitive, because the column is: registration writes the
        // address as typed, so `Mixed@Example.com` and `mixed@example.com`
        // are two rows this probe cannot see as one. Pre-existing and not
        // widened here — the fix is a normalisation pass on the register
        // write, which is where the two spellings are created.
        const existing = await prisma.user.findUnique({
          where: { email: normalizedEmail },
          select: { id: true },
        });
        if (existing && existing.id !== userId) {
          // The informative answer is the one worth recording: it says an
          // account holds that address. The ordinary save's `profile.update`
          // row is written further down and this path never reaches it, so
          // without a row here the only probes in the ledger would be the
          // ones that came back negative.
          annotate({ action: { name: "profile.email.conflict" } });
          await auditLog("profile.email.conflict", {
            userId,
            ipAddress: ipAddress ?? null,
          });
          return {
            ok: false,
            status: 409,
            message: "Email already in use",
            errorCode: "profile.update.emailInUse",
          };
        }
      }
    }
  }

  const updates: Record<string, unknown> = {};
  if (data.email !== undefined) updates.email = normalizedEmail;
  if (data.heightCm !== undefined) updates.heightCm = data.heightCm ?? null;
  if (data.dateOfBirth !== undefined) {
    updates.dateOfBirth = data.dateOfBirth ? new Date(data.dateOfBirth) : null;
  }
  if (data.gender !== undefined) updates.gender = data.gender;
  if (data.displayName !== undefined) {
    updates.displayName =
      data.displayName === null || data.displayName === ""
        ? null
        : data.displayName.trim();
  }
  if (data.locale !== undefined) updates.locale = data.locale;
  if (data.timezone !== undefined) updates.timezone = data.timezone;
  if (data.timeFormat !== undefined) updates.timeFormat = data.timeFormat;
  if (data.dateFormat !== undefined) updates.dateFormat = data.dateFormat;
  if (data.moodReminderEnabled !== undefined) {
    updates.moodReminderEnabled = data.moodReminderEnabled;
  }
  // v1.7.0 — patient-identity fields. Plaintext for fullName/insurerName;
  // KVNR is encrypted at rest. An empty string collapses to null so the
  // export cover + FHIR Patient omit the line entirely.
  if (data.fullName !== undefined) {
    updates.fullName =
      data.fullName === null || data.fullName === "" ? null : data.fullName;
  }
  if (data.insurerName !== undefined) {
    updates.insurerName =
      data.insurerName === null || data.insurerName === ""
        ? null
        : data.insurerName;
  }
  // v1.8.6 — IKNR plaintext (matches insurerName). The Zod transform
  // already mapped empty → null, so a null here means "clear it".
  if (data.insurerIkNumber !== undefined) {
    updates.insurerIkNumber = data.insurerIkNumber ?? null;
  }
  if (data.insuranceNumber !== undefined) {
    updates.insuranceNumberEncrypted =
      data.insuranceNumber === null || data.insuranceNumber === ""
        ? null
        : encrypt(data.insuranceNumber);
  }

  // v1.4.18 — capture the prior locale so we can emit a separate
  // `settings.locale.update` audit row when the locale actually
  // changes. The hidden "polyglot" achievement watches that action,
  // and we don't want to fire it on profile updates that happen to
  // touch other fields.
  const priorLocale =
    data.locale !== undefined
      ? ((
          await prisma.user.findUnique({
            where: { id: userId },
            select: { locale: true },
          })
        )?.locale ?? null)
      : null;

  const updatedUser = await prisma.user.update({
    where: { id: userId },
    data: updates,
  });

  // Anthropometrics feed the cached targets grid (BMI band, BP-by-age
  // range, body-fat band), the derived-score baseline profile (age /
  // sex / height) and the analytics snapshot. Only those three fields
  // matter here — a display-name or email edit must not cold-rebuild
  // the analytics caches.
  if (
    data.heightCm !== undefined ||
    data.dateOfBirth !== undefined ||
    data.gender !== undefined
  ) {
    invalidateUserProfile(userId);
  }

  // v1.16.9 — the medication payloads (list next-due, today counts, the
  // compliance day buckets) are computed in the user's timezone, but the
  // list cache key carries only the userId. A timezone change must evict
  // the bucket or the next read serves the previous zone's day grid.
  if (data.timezone !== undefined) {
    invalidateUserMedications(userId, { evict: true });
  }

  await auditLog("profile.update", {
    userId: updatedUser.id,
    ipAddress: ipAddress ?? null,
  });

  if (data.locale !== undefined && priorLocale !== data.locale) {
    await auditLog("settings.locale.update", {
      userId: updatedUser.id,
      ipAddress: ipAddress ?? null,
      details: { from: priorLocale, to: data.locale ?? null },
    });
  }

  return {
    ok: true,
    user: {
      id: updatedUser.id,
      username: updatedUser.username,
      displayName: updatedUser.displayName,
      email: updatedUser.email,
      role: updatedUser.role,
      heightCm: updatedUser.heightCm,
      dateOfBirth: updatedUser.dateOfBirth,
      gender: updatedUser.gender,
      timezone: updatedUser.timezone,
      locale: updatedUser.locale,
      timeFormat: updatedUser.timeFormat ?? "AUTO",
      dateFormat: updatedUser.dateFormat ?? "AUTO",
      moodReminderEnabled: updatedUser.moodReminderEnabled,
      fullName: updatedUser.fullName,
      insurerName: updatedUser.insurerName,
      insurerIkNumber: updatedUser.insurerIkNumber,
      hasInsuranceNumber: updatedUser.insuranceNumberEncrypted != null,
    },
    ...(rejectedFields.length > 0 ? { rejectedFields } : {}),
  };
}