"use server";

import { createAdminClient } from "@/lib/supabase/server";
import { auth } from "@clerk/nextjs/server";
import type { PayrollSettings } from "@/lib/payroll-settings-types";

async function getOrganisationId(): Promise<string> {
  const { userId } = await auth();
  if (!userId) throw new Error("Unauthenticated");

  const supabase = await createAdminClient();
  const { data: member, error } = await supabase
    .from("organisation_members")
    .select("organisation_id")
    .eq("user_id", userId)
    .single();

  if (error || !member) throw new Error("No organisation found");
  return member.organisation_id;
}

/**
 * Fetch the payroll settings for the current user's organisation.
 */
export async function fetchPayrollSettings(): Promise<PayrollSettings | null> {
  const orgId = await getOrganisationId();
  const supabase = await createAdminClient();

  const { data, error } = await supabase
    .from("payroll_settings")
    .select("*")
    .eq("organisation_id", orgId)
    .single();

  if (error && error.code !== "PGRST116") throw error; // PGRST116 = not found
  return data as PayrollSettings | null;
}

/**
 * Save payroll settings for the current organisation.
 * Creates if not exists, updates if exists.
 */
export async function savePayrollSettings(
  input: Omit<PayrollSettings, "id" | "organisation_id" | "created_at" | "updated_at">
): Promise<{ success: boolean; error?: string }> {
  const orgId = await getOrganisationId();
  const supabase = await createAdminClient();

  // Check if settings already exist
  const { data: existing } = await supabase
    .from("payroll_settings")
    .select("id")
    .eq("organisation_id", orgId)
    .single();

  const payload = {
    organisation_id: orgId,
    country_code: input.country_code,
    country_name: input.country_name,
    currency: input.currency,
    is_natively_supported: input.is_natively_supported,
    state_code: input.state_code,
    state_name: input.state_name,
    state_tax_rate: input.state_tax_rate,
    is_singapore_citizen_or_pr: input.is_singapore_citizen_or_pr,
    flat_income_tax_rate: input.flat_income_tax_rate,
    employer_pension_rate: input.employer_pension_rate,
    employer_tax_rate: input.employer_tax_rate,
    tax_free_allowance: input.tax_free_allowance,
  };

  if (existing) {
    const { error } = await supabase
      .from("payroll_settings")
      .update(payload)
      .eq("id", existing.id);

    if (error) return { success: false, error: error.message };
  } else {
    const { error } = await supabase
      .from("payroll_settings")
      .insert(payload);

    if (error) return { success: false, error: error.message };
  }

  return { success: true };
}