/**
 * T-159…T-161 — Task DTOs (Zod, validated by the global ZodValidate pipe).
 *
 * A Task is a 1:1 sidecar of a `pages.kind='task'` page (A-006): the page
 * carries the blocks/comments/permissions tree; the sidecar carries the
 * queryable task fields (status/due/assignees). `assigneeIds` uses Prisma's
 * `String[]` — the API exposes it as a JSON array (additive-only, no new
 * column types).
 */
import { z } from "zod";

/** Task status machine (T-159): todo | in_progress | done | cancelled. */
export const TASK_STATUSES = ["todo", "in_progress", "done", "cancelled"] as const;
export type TaskStatus = (typeof TASK_STATUSES)[number];

/**
 * Legal transitions (T-160's "inbox" semantics lean on this; enforced in the
 * service — an illegal transition is 400, not a silent overwrite).
 *   todo        → in_progress | done | cancelled
 *   in_progress → done | cancelled | todo
 *   done        → in_progress            (re-open)
 *   cancelled   → todo                   (re-open)
 */
export const TASK_TRANSITIONS: Record<TaskStatus, TaskStatus[]> = {
  todo: ["in_progress", "done", "cancelled"],
  in_progress: ["done", "cancelled", "todo"],
  done: ["in_progress"],
  cancelled: ["todo"]
};

/** `GET /workspaces/:workspaceId/tasks` — inbox + filters. */
export const ListTasksQuery = z.object({
  /** `inbox` = tasks where the CALLER is an assignee (the default); `all` = every task in the workspace. */
  scope: z.enum(["inbox", "all"]).default("inbox"),
  status: z.enum(TASK_STATUSES).optional(),
  /** due before this ISO date (overdue tab). */
  dueBefore: z.string().datetime({ offset: true }).optional(),
  /** due after this ISO date. */
  dueAfter: z.string().datetime({ offset: true }).optional(),
  /** calendar tab: tasks whose dueAt falls in [monthStart, monthEnd) UTC. */
  month: z
    .string()
    .regex(/^\d{4}-(0[1-9]|1[0-2])$/, "month must be YYYY-MM")
    .optional(),
  /** overdue = dueAt < now && status not in (done, cancelled). Shorthand for the client. */
  overdue: z.coerce.boolean().optional(),
  cursor: z.string().optional(),
  limit: z.coerce.number().int().min(1).max(100).default(50)
});
export type ListTasksQueryInput = z.infer<typeof ListTasksQuery>;

/** `POST /workspaces/:workspaceId/tasks` — create a task page + sidecar. */
export const CreateTaskDto = z.object({
  title: z.string().min(1).max(500),
  parentId: z.string().min(1).optional(),
  status: z.enum(TASK_STATUSES).default("todo"),
  dueAt: z.string().datetime({ offset: true }).nullable().optional(),
  assigneeIds: z.array(z.string().min(1)).max(50).default([])
});
export type CreateTaskInput = z.infer<typeof CreateTaskDto>;

/** `PATCH /tasks/:id` — partial update of the sidecar fields. */
export const UpdateTaskDto = z
  .object({
    title: z.string().min(1).max(500).optional(),
    status: z.enum(TASK_STATUSES).optional(),
    dueAt: z.string().datetime({ offset: true }).nullable().optional(),
    /**
     * Assignees: an ARRAY replaces the whole list (the client sends the full
     * set); `null` clears it. Individual user add/remove is a convenience
     * `addAssignee`/`removeAssignee` pair of single-element patches — but the
     * canonical wire shape is the full list (matches Prisma `String[]`).
     */
    assigneeIds: z.array(z.string().min(1)).max(50).nullable().optional()
  })
  .refine((v) => Object.keys(v).length > 0, { message: "No fields to update" });
export type UpdateTaskInput = z.infer<typeof UpdateTaskDto>;