"use server";

import { revalidatePath } from "next/cache";

import { prisma } from "@/lib/db";
import { requireUserId } from "@/lib/auth-helpers";
import { boardPath, projectAccessFilter, scheduledTodoAccessFilter } from "@/lib/access";
import {
  RecurrenceInputSchema,
  ScheduledTodoDetailsSchema,
  ScheduledTodoTitleSchema,
  type RecurrenceInput,
} from "@/lib/validation/scheduled-todo";
import { buildRRuleString, parseRRuleString } from "@/lib/rrule-utils";
import { getScheduledTodoBoard } from "@/lib/scheduled-todos";
import type { ScheduledBoardDTO, ScheduledTodoEditDTO } from "@/types/scheduled-todo";

/** Verifies the project (Home scope is always allowed for its own user). */
async function assertProjectAccess(userId: string, projectId: string) {
  const project = await prisma.project.findFirst({
    where: { id: projectId, ...projectAccessFilter(userId) },
    select: { id: true },
  });
  if (!project) throw new Error("Project not found");
}

async function findOwnedScheduledTodo(userId: string, id: string) {
  const todo = await prisma.scheduledTodo.findFirst({
    where: { id, ...scheduledTodoAccessFilter(userId) },
    select: { id: true, projectId: true },
  });
  if (!todo) throw new Error("Scheduled to-do not found");
  return todo;
}

/** The action the client Scheduled panel calls -- it derives Home vs.
 * Project scope from the current route itself (see ScheduledPanel), so this
 * is the single entry point regardless of which board is showing. */
export async function getScheduledBoard(projectId: string | null): Promise<ScheduledBoardDTO> {
  const userId = await requireUserId();
  if (projectId) {
    await assertProjectAccess(userId, projectId);
    return getScheduledTodoBoard({ projectId });
  }
  return getScheduledTodoBoard({ userId, projectId: null });
}

export async function getScheduledTodoForEdit(id: string): Promise<ScheduledTodoEditDTO> {
  const userId = await requireUserId();
  const todo = await prisma.scheduledTodo.findFirst({
    where: { id, ...scheduledTodoAccessFilter(userId) },
  });
  if (!todo) throw new Error("Scheduled to-do not found");

  return {
    id: todo.id,
    title: todo.title,
    details: todo.details,
    startDate: todo.startDate.toISOString().slice(0, 10),
    recurrence: todo.rrule ? parseRRuleString(todo.rrule) : null,
  };
}

export async function createScheduledTodo(
  scope: { projectId: string | null },
  data: { title: string; details?: string; startDate: string; recurrence?: RecurrenceInput }
): Promise<void> {
  const userId = await requireUserId();
  const title = ScheduledTodoTitleSchema.parse(data.title);
  const details = data.details ? ScheduledTodoDetailsSchema.parse(data.details) : undefined;
  const recurrence = data.recurrence ? RecurrenceInputSchema.parse(data.recurrence) : undefined;

  if (scope.projectId) await assertProjectAccess(userId, scope.projectId);

  await prisma.scheduledTodo.create({
    data: {
      title,
      details: details ?? null,
      userId: scope.projectId ? null : userId,
      projectId: scope.projectId,
      startDate: new Date(data.startDate),
      rrule: recurrence ? buildRRuleString(recurrence) : null,
    },
  });

  revalidatePath(boardPath(scope.projectId));
}

export async function updateScheduledTodo(
  id: string,
  data: {
    title?: string;
    details?: string | null;
    startDate?: string;
    recurrence?: RecurrenceInput | null;
  }
): Promise<void> {
  const userId = await requireUserId();
  const todo = await findOwnedScheduledTodo(userId, id);

  const update: {
    title?: string;
    details?: string | null;
    startDate?: Date;
    rrule?: string | null;
  } = {};
  if (data.title !== undefined) update.title = ScheduledTodoTitleSchema.parse(data.title);
  if (data.details !== undefined) {
    update.details = data.details ? ScheduledTodoDetailsSchema.parse(data.details) : null;
  }
  if (data.startDate !== undefined) update.startDate = new Date(data.startDate);
  if (data.recurrence !== undefined) {
    update.rrule = data.recurrence ? buildRRuleString(RecurrenceInputSchema.parse(data.recurrence)) : null;
  }

  await prisma.scheduledTodo.update({ where: { id }, data: update });

  revalidatePath(boardPath(todo.projectId));
}

export async function deleteScheduledTodo(id: string): Promise<void> {
  const userId = await requireUserId();
  const todo = await findOwnedScheduledTodo(userId, id);

  await prisma.scheduledTodo.delete({ where: { id } });

  revalidatePath(boardPath(todo.projectId));
}

/** Toggles just one date's occurrence -- a recurring to-do's other dates
 * are unaffected (see ScheduledTodoCompletion). */
export async function toggleScheduledOccurrence(
  scheduledTodoId: string,
  occurrenceDate: string,
  completed: boolean
): Promise<void> {
  const userId = await requireUserId();
  const todo = await findOwnedScheduledTodo(userId, scheduledTodoId);
  const date = new Date(occurrenceDate);

  if (completed) {
    await prisma.scheduledTodoCompletion.upsert({
      where: { scheduledTodoId_occurrenceDate: { scheduledTodoId, occurrenceDate: date } },
      create: { scheduledTodoId, occurrenceDate: date },
      update: {},
    });
  } else {
    await prisma.scheduledTodoCompletion.deleteMany({
      where: { scheduledTodoId, occurrenceDate: date },
    });
  }

  revalidatePath(boardPath(todo.projectId));
}