"use server";

import { and, asc, eq, gte, inArray, lte, or, sql } from "drizzle-orm";
import { z } from "zod";
import { db } from "@/lib/db";
import { getCurrentSession } from "@/lib/session";
import { normalizeReminderOffsets } from "@/lib/reminder-offsets";
import { listReminderOffsets } from "@/modules/_core/reminders";
import { householdMembers } from "@/modules/_core/schema";
import { calendarEvents, calendars } from "../schema";

export type ApiScope = {
  householdId: string;
  userId: string | null;
};

export type CalendarDto = {
  id: string;
  name: string;
  color: string | null;
  visibility: "private" | "household";
  ownerId: string;
};

export type CalendarEventDto = {
  id: string;
  calendarId: string;
  title: string;
  startAt: string;
  endAt: string;
  allDay: boolean;
  location: string | null;
  notes: string | null;
};

const listEventsSchema = z.object({
  from: z.coerce.date(),
  to: z.coerce.date(),
  calendarIds: z.union([z.literal("all"), z.array(z.string().uuid())]),
});

function calendarVisibilityFilter(scope: ApiScope) {
  if (scope.userId) {
    return or(eq(calendars.visibility, "household"), eq(calendars.ownerId, scope.userId));
  }
  return eq(calendars.visibility, "household");
}

export async function canSeeCalendarForScope(scope: ApiScope, calendarId: string) {
  const [row] = await db
    .select({
      visibility: calendars.visibility,
      ownerId: calendars.ownerId,
      householdId: calendars.householdId,
    })
    .from(calendars)
    .where(eq(calendars.id, calendarId))
    .limit(1);

  if (!row || row.householdId !== scope.householdId) return false;
  if (row.visibility === "household") return true;
  if (!scope.userId) return false;
  return row.ownerId === scope.userId;
}

export async function canSeeCalendar(userId: string, calendarId: string) {
  const [row] = await db
    .select({
      calendarId: calendars.id,
      visibility: calendars.visibility,
      ownerId: calendars.ownerId,
      memberUserId: householdMembers.userId,
    })
    .from(calendars)
    .leftJoin(
      householdMembers,
      and(
        eq(householdMembers.householdId, calendars.householdId),
        eq(householdMembers.userId, userId),
      ),
    )
    .where(eq(calendars.id, calendarId))
    .limit(1);

  if (!row) return false;
  if (row.visibility === "private") return row.ownerId === userId;
  return row.memberUserId === userId;
}

export async function listCalendarsForScope(scope: ApiScope): Promise<CalendarDto[]> {
  const rows = await db
    .select({
      id: calendars.id,
      name: calendars.name,
      color: calendars.color,
      visibility: calendars.visibility,
      ownerId: calendars.ownerId,
    })
    .from(calendars)
    .where(and(eq(calendars.householdId, scope.householdId), calendarVisibilityFilter(scope)))
    .orderBy(asc(calendars.name));

  return rows.map((row) => ({
    ...row,
    visibility: row.visibility as "private" | "household",
  }));
}

export async function listCalendars(): Promise<CalendarDto[]> {
  const { user, household } = await getCurrentSession();
  return listCalendarsForScope({ householdId: household.id, userId: user.id });
}

export async function getCalendarForScope(scope: ApiScope, id: string): Promise<CalendarDto> {
  const parsed = z.string().uuid().parse(id);
  const [row] = await db
    .select({
      id: calendars.id,
      name: calendars.name,
      color: calendars.color,
      visibility: calendars.visibility,
      ownerId: calendars.ownerId,
      householdId: calendars.householdId,
    })
    .from(calendars)
    .where(and(eq(calendars.id, parsed), eq(calendars.householdId, scope.householdId)))
    .limit(1);

  if (!row) throw new Error("Calendar not found");
  if (!(await canSeeCalendarForScope(scope, row.id))) throw new Error("Calendar not found");

  return {
    id: row.id,
    name: row.name,
    color: row.color,
    visibility: row.visibility as "private" | "household",
    ownerId: row.ownerId,
  };
}

export async function listEventsForScope(
  scope: ApiScope,
  input: {
    from: Date | string;
    to: Date | string;
    calendarIds: "all" | string[];
  },
): Promise<CalendarEventDto[]> {
  const parsed = listEventsSchema.parse(input);
  const visibleCalendars = await listCalendarsForScope(scope);
  const visibleIds = new Set(visibleCalendars.map((calendar) => calendar.id));
  const calendarIds =
    parsed.calendarIds === "all"
      ? [...visibleIds]
      : parsed.calendarIds.filter((id) => visibleIds.has(id));

  if (calendarIds.length === 0) return [];

  const rows = await db
    .select({
      id: calendarEvents.id,
      calendarId: calendarEvents.calendarId,
      title: calendarEvents.title,
      startAt: calendarEvents.startAt,
      endAt: calendarEvents.endAt,
      allDay: calendarEvents.allDay,
      location: calendarEvents.location,
      notes: calendarEvents.notes,
    })
    .from(calendarEvents)
    .where(
      and(
        inArray(calendarEvents.calendarId, calendarIds),
        lte(calendarEvents.startAt, parsed.to),
        gte(calendarEvents.endAt, parsed.from),
      ),
    )
    .orderBy(asc(calendarEvents.startAt));

  return rows.map(toEventDto);
}

export async function listEvents(input: {
  from: Date | string;
  to: Date | string;
  calendarIds: "all" | string[];
}): Promise<CalendarEventDto[]> {
  const { user, household } = await getCurrentSession();
  return listEventsForScope({ householdId: household.id, userId: user.id }, input);
}

export async function getEventForScope(scope: ApiScope, id: string): Promise<CalendarEventDto> {
  const parsed = z.string().uuid().parse(id);
  const [row] = await db
    .select({
      id: calendarEvents.id,
      calendarId: calendarEvents.calendarId,
      title: calendarEvents.title,
      startAt: calendarEvents.startAt,
      endAt: calendarEvents.endAt,
      allDay: calendarEvents.allDay,
      location: calendarEvents.location,
      notes: calendarEvents.notes,
      householdId: calendars.householdId,
    })
    .from(calendarEvents)
    .innerJoin(calendars, eq(calendarEvents.calendarId, calendars.id))
    .where(and(eq(calendarEvents.id, parsed), eq(calendars.householdId, scope.householdId)))
    .limit(1);

  if (!row) throw new Error("Event not found");
  if (!(await canSeeCalendarForScope(scope, row.calendarId))) throw new Error("Event not found");

  return toEventDto(row);
}

export async function searchCalendars(query: string, householdId: string) {
  const rows = await db
    .select({ id: calendars.id, name: calendars.name })
    .from(calendars)
    .where(
      and(eq(calendars.householdId, householdId), sql`${calendars.name} ilike ${`%${query}%`}`),
    )
    .limit(10);

  return rows.map((row) => ({
    id: row.id,
    title: row.name,
    url: `/calendar?id=${row.id}`,
  }));
}

export async function searchEvents(query: string, householdId: string) {
  const rows = await db
    .select({
      id: calendarEvents.id,
      title: calendarEvents.title,
      location: calendarEvents.location,
      notes: calendarEvents.notes,
    })
    .from(calendarEvents)
    .innerJoin(calendars, eq(calendarEvents.calendarId, calendars.id))
    .where(
      and(
        eq(calendars.householdId, householdId),
        or(
          sql`${calendarEvents.title} ilike ${`%${query}%`}`,
          sql`${calendarEvents.location} ilike ${`%${query}%`}`,
          sql`${calendarEvents.notes} ilike ${`%${query}%`}`,
        ),
      ),
    )
    .limit(10);

  return rows.map((row) => ({
    id: row.id,
    title: row.title,
    url: `/calendar/events/${row.id}`,
    excerpt: row.location ?? row.notes ?? undefined,
  }));
}

export async function getDefaultEventReminderOffsets(): Promise<number[]> {
  const { user } = await getCurrentSession();
  return normalizeReminderOffsets(user.defaultEventReminderOffsets ?? [30]);
}

export async function getEventReminderOffsets(eventId: string): Promise<number[]> {
  const parsed = z.string().uuid().parse(eventId);
  const { user, household } = await getCurrentSession();
  const event = await getEventForScope({ householdId: household.id, userId: user.id }, parsed);
  if (!event) throw new Error("Event not found");
  return listReminderOffsets("calendar.event", parsed);
}

function toEventDto(row: {
  id: string;
  calendarId: string;
  title: string;
  startAt: Date;
  endAt: Date;
  allDay: boolean;
  location: string | null;
  notes: string | null;
}): CalendarEventDto {
  return {
    ...row,
    startAt: row.startAt.toISOString(),
    endAt: row.endAt.toISOString(),
  };
}