import { z } from "zod";
import { NextResponse } from "next/server";

export const TASK_STATUSES = ["PENDING", "DONE", "IN_PROGRESS", "CANCELLED"] as const;
export const REPORT_STATUSES = ["IN_PROGRESS", "COMPLETED", "SUBMITTED"] as const;

const httpLink = z
  .string()
  .trim()
  .max(2000)
  .refine((v) => v === "" || /^https?:\/\//i.test(v), {
    message: "Link must start with http:// or https://",
  });

export const createReportSchema = z.object({
  managerName: z.string().trim().min(1).max(200),
  date: z
    .string()
    .regex(/^\d{4}-\d{2}-\d{2}$/, "Date must be YYYY-MM-DD")
    .optional(),
});

export const updateReportSchema = z.object({
  managerName: z.string().trim().min(1).max(200).optional(),
  status: z.enum(REPORT_STATUSES).optional(),
});

export const createTaskSchema = z.object({
  reportId: z.string().min(1),
  type: z.enum(["PLANNED", "COMPLETED"]),
  description: z.string().max(2000).default(""),
  timeEstimate: z.string().max(100).nullish(),
  notes: z.string().max(2000).nullish(),
  link: httpLink.nullish(),
  status: z.enum(TASK_STATUSES).nullish(),
});

export const updateTaskSchema = z.object({
  id: z.string().min(1),
  type: z.enum(["PLANNED", "COMPLETED"]).optional(),
  description: z.string().max(2000).optional(),
  timeEstimate: z.string().max(100).nullish(),
  notes: z.string().max(2000).nullish(),
  link: httpLink.nullish(),
  status: z.enum(TASK_STATUSES).nullish(),
});

export const updateSettingSchema = z.object({
  key: z.enum(["GOOGLE_DRIVE_FOLDER_ID"]),
  value: z.string().trim().max(500),
});

export const updateUserRoleSchema = z.object({
  userId: z.string().min(1),
  role: z.enum(["EMPLOYEE", "ADMIN"]),
});

/**
 * Parse and validate a request body. Returns the parsed data, or a
 * NextResponse 400 that the route should return immediately.
 */
export async function parseBody<T extends z.ZodTypeAny>(
  req: Request,
  schema: T
): Promise<{ data: z.infer<T>; error: null } | { data: null; error: NextResponse }> {
  let json: unknown;
  try {
    json = await req.json();
  } catch {
    return {
      data: null,
      error: NextResponse.json({ error: "Invalid JSON body" }, { status: 400 }),
    };
  }

  const result = schema.safeParse(json);
  if (!result.success) {
    return {
      data: null,
      error: NextResponse.json(
        { error: "Validation failed", details: result.error.flatten().fieldErrors },
        { status: 400 }
      ),
    };
  }

  return { data: result.data, error: null };
}