import { z } from "zod";

export const ScheduledTodoTitleSchema = z
  .string()
  .trim()
  .min(1, "Title is required")
  .max(100, "Title must be 100 characters or fewer");

export const ScheduledTodoDetailsSchema = z.string().max(5_000).optional();

// "HH:MM", 24-hour -- exactly what an <input type="time"> gives back, so
// the client never needs to reformat before sending it.
export const ScheduledTodoTimeDueSchema = z
  .string()
  .regex(/^([01]\d|2[0-3]):[0-5]\d$/, "Invalid time");

// Minutes of lead time before timeDue -- 0 ("When due") up to a week.
export const ScheduledTodoRemindMinutesBeforeSchema = z.number().int().min(0).max(10_080);

const DateStringSchema = z.string().regex(/^\d{4}-\d{2}-\d{2}$/, "Invalid date");

const RecurrenceEndSchema = z.discriminatedUnion("type", [
  z.object({ type: z.literal("never") }),
  z.object({ type: z.literal("until"), date: DateStringSchema }),
  z.object({ type: z.literal("count"), count: z.number().int().min(1).max(999) }),
]);

/**
 * What the "Add/Edit Scheduled To-Do" dialog submits for the recurring
 * case -- validated here and only here turned into an RFC 5545 RRULE
 * string (see lib/rrule-utils.ts). Never trust a client-supplied RRULE
 * string directly.
 */
export const RecurrenceInputSchema = z
  .object({
    frequency: z.enum(["DAILY", "WEEKLY", "MONTHLY", "YEARLY"]),
    interval: z.number().int().min(1).max(365),
    // 0 = Sunday .. 6 = Saturday, matching Date#getUTCDay().
    daysOfWeek: z.array(z.number().int().min(0).max(6)).max(7).optional(),
    dayOfMonth: z.number().int().min(1).max(31).optional(),
    month: z.number().int().min(1).max(12).optional(),
    end: RecurrenceEndSchema,
  })
  .superRefine((value, ctx) => {
    if (value.frequency === "WEEKLY" && !value.daysOfWeek?.length) {
      ctx.addIssue({
        code: "custom",
        path: ["daysOfWeek"],
        message: "Pick at least one day of the week",
      });
    }
    if ((value.frequency === "MONTHLY" || value.frequency === "YEARLY") && !value.dayOfMonth) {
      ctx.addIssue({ code: "custom", path: ["dayOfMonth"], message: "Day of month is required" });
    }
    if (value.frequency === "YEARLY" && !value.month) {
      ctx.addIssue({ code: "custom", path: ["month"], message: "Month is required" });
    }
  });

export type RecurrenceInput = z.infer<typeof RecurrenceInputSchema>;