// ABOUTME: API route for user profile management.
// ABOUTME: Handles GET for profile retrieval and PATCH for updates.
import type { NextRequest } from "next/server";
import { NextResponse } from "next/server";

import { withAuth } from "@/lib/auth-middleware";

// Validation constants
const CYCLE_LENGTH_MIN = 21;
const CYCLE_LENGTH_MAX = 45;
const TIME_FORMAT_REGEX = /^([01]\d|2[0-3]):([0-5]\d)$/;

/**
 * GET /api/user
 * Returns the authenticated user's profile.
 * Fetches fresh data from database to ensure updates are reflected.
 * Excludes sensitive fields like encrypted tokens.
 */
export const GET = withAuth(async (_request, user, pb) => {
  // Fetch fresh user data from database to get latest values
  // The user param from withAuth is from auth store cache which may be stale
  const freshUser = await pb.collection("users").getOne(user.id);

  // Format date for consistent API response
  const lastPeriodDate = freshUser.lastPeriodDate
    ? new Date(freshUser.lastPeriodDate as string).toISOString().split("T")[0]
    : null;

  return NextResponse.json(
    {
      id: freshUser.id,
      email: freshUser.email,
      garminConnected: freshUser.garminConnected ?? false,
      cycleLength: freshUser.cycleLength,
      lastPeriodDate,
      notificationTime: freshUser.notificationTime,
      timezone: freshUser.timezone,
      activeOverrides: freshUser.activeOverrides ?? [],
      calendarToken: (freshUser.calendarToken as string) || null,
    },
    {
      headers: { "Cache-Control": "no-store, no-cache, must-revalidate" },
    },
  );
});

/**
 * Validates cycleLength field.
 * Must be a number between CYCLE_LENGTH_MIN and CYCLE_LENGTH_MAX.
 */
function validateCycleLength(value: unknown): string | null {
  if (typeof value !== "number" || Number.isNaN(value)) {
    return "cycleLength must be a number";
  }
  if (value < CYCLE_LENGTH_MIN || value > CYCLE_LENGTH_MAX) {
    return `cycleLength must be between ${CYCLE_LENGTH_MIN} and ${CYCLE_LENGTH_MAX}`;
  }
  return null;
}

/**
 * Validates notificationTime field.
 * Must be in HH:MM format (24-hour).
 */
function validateNotificationTime(value: unknown): string | null {
  if (typeof value !== "string") {
    return "notificationTime must be a string in HH:MM format";
  }
  if (!TIME_FORMAT_REGEX.test(value)) {
    return "notificationTime must be in HH:MM format (00:00-23:59)";
  }
  return null;
}

/**
 * Validates timezone field.
 * Must be a non-empty string.
 */
function validateTimezone(value: unknown): string | null {
  if (typeof value !== "string") {
    return "timezone must be a string";
  }
  if (value.trim() === "") {
    return "timezone cannot be empty";
  }
  return null;
}

/**
 * PATCH /api/user
 * Updates the authenticated user's profile.
 * Allowed fields: cycleLength, notificationTime, timezone
 */
export const PATCH = withAuth(async (request: NextRequest, user, pb) => {
  const body = await request.json();

  // Build update object with only valid, updatable fields
  const updates: Record<string, unknown> = {};
  const errors: string[] = [];

  // Validate and collect cycleLength
  if (body.cycleLength !== undefined) {
    const error = validateCycleLength(body.cycleLength);
    if (error) {
      errors.push(error);
    } else {
      updates.cycleLength = body.cycleLength;
    }
  }

  // Validate and collect notificationTime
  if (body.notificationTime !== undefined) {
    const error = validateNotificationTime(body.notificationTime);
    if (error) {
      errors.push(error);
    } else {
      updates.notificationTime = body.notificationTime;
    }
  }

  // Validate and collect timezone
  if (body.timezone !== undefined) {
    const error = validateTimezone(body.timezone);
    if (error) {
      errors.push(error);
    } else {
      updates.timezone = body.timezone;
    }
  }

  // Return validation errors if any
  if (errors.length > 0) {
    return NextResponse.json({ error: errors.join("; ") }, { status: 400 });
  }

  // Check if there are any fields to update
  if (Object.keys(updates).length === 0) {
    return NextResponse.json(
      { error: "No valid fields to update" },
      { status: 400 },
    );
  }

  // Update the user record in PocketBase
  await pb.collection("users").update(user.id, updates);

  // Build updated user profile for response
  const updatedUser = {
    ...user,
    ...updates,
  };

  // Format date for consistent API response
  const lastPeriodDate = updatedUser.lastPeriodDate
    ? updatedUser.lastPeriodDate.toISOString().split("T")[0]
    : null;

  return NextResponse.json({
    id: updatedUser.id,
    email: updatedUser.email,
    garminConnected: updatedUser.garminConnected,
    cycleLength: updatedUser.cycleLength,
    lastPeriodDate,
    notificationTime: updatedUser.notificationTime,
    timezone: updatedUser.timezone,
    activeOverrides: updatedUser.activeOverrides,
  });
});