import { useEffect, useMemo, useState } from "react";
import type {
  OrganizationFunctionLabelContext,
  OrganizationFunctionPickerContext,
  OrganizationFunctionSelection
} from "@govoplan/core-webui";
import { getOrganizationModel, type OrganizationFunctionItem, type OrganizationModel, type OrganizationUnitItem } from "../../api/organizations";

type FunctionOption = OrganizationFunctionSelection & {
  slug: string;
  active: boolean;
};

export function OrganizationFunctionPicker({ settings, auth, value, disabled, onChange }: OrganizationFunctionPickerContext) {
  const [model, setModel] = useState<OrganizationModel | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState("");
  const tenantId = (auth.active_tenant ?? auth.tenant).id;

  useEffect(() => {
    let cancelled = false;
    setLoading(true);
    setError("");
    getOrganizationModel(settings)
      .then((nextModel) => {
        if (!cancelled) setModel(nextModel);
      })
      .catch((err: unknown) => {
        if (!cancelled) setError(err instanceof Error ? err.message : String(err));
      })
      .finally(() => {
        if (!cancelled) setLoading(false);
      });
    return () => {
      cancelled = true;
    };
  }, [settings.accessToken, settings.apiBaseUrl, tenantId]);

  const options = useMemo(() => functionOptions(model), [model]);
  const selectedId = value?.functionId ?? "";

  return (
    <>
      <select
        value={selectedId}
        disabled={disabled || loading || Boolean(error)}
        onChange={(event) => {
          const selected = options.find((option) => option.functionId === event.target.value);
          onChange(selected ?? null);
        }}
      >
        <option value="">{loading ? "i18n:govoplan-organizations.loading_functions.77e8e684" : "i18n:govoplan-organizations.select_function.4895a67d"}</option>
        {options.map((option) => (
          <option key={option.functionId} value={option.functionId}>
            {option.label}{option.organizationUnitLabel ? ` (${option.organizationUnitLabel})` : ""}
          </option>
        ))}
      </select>
      {error && <p className="muted small-note">i18n:govoplan-organizations.functions_unavailable.4fd6765d</p>}
    </>
  );
}

export function OrganizationFunctionLabel({ settings, auth, sourceModule, functionId, fallback }: OrganizationFunctionLabelContext) {
  const [model, setModel] = useState<OrganizationModel | null>(null);
  const tenantId = (auth.active_tenant ?? auth.tenant).id;

  useEffect(() => {
    let cancelled = false;
    getOrganizationModel(settings)
      .then((nextModel) => {
        if (!cancelled) setModel(nextModel);
      })
      .catch(() => {
        if (!cancelled) setModel(null);
      });
    return () => {
      cancelled = true;
    };
  }, [settings.accessToken, settings.apiBaseUrl, tenantId]);

  const option = useMemo(() => functionOptions(model).find((item) => item.functionId === functionId), [functionId, model]);
  if (sourceModule !== "organizations" || !option) return <>{fallback ?? functionId}</>;
  return (
    <div>
      <strong>{option.label}</strong>
      <div className="muted small-note">{option.organizationUnitLabel ?? option.slug}</div>
    </div>
  );
}

function functionOptions(model: OrganizationModel | null): FunctionOption[] {
  if (!model) return [];
  const unitById = new Map<string, OrganizationUnitItem>(model.units.map((unit) => [unit.id, unit]));
  return model.functions
    .filter((item) => item.is_active)
    .map((item) => toOption(item, unitById.get(item.organization_unit_id)))
    .sort((left, right) => {
      const unitDelta = (left.organizationUnitLabel ?? "").localeCompare(right.organizationUnitLabel ?? "");
      return unitDelta !== 0 ? unitDelta : (left.label ?? left.functionId).localeCompare(right.label ?? right.functionId);
    });
}

function toOption(item: OrganizationFunctionItem, unit: OrganizationUnitItem | undefined): FunctionOption {
  return {
    sourceModule: "organizations",
    functionId: item.id,
    label: item.name,
    organizationUnitId: item.organization_unit_id,
    organizationUnitLabel: unit?.name ?? null,
    slug: item.slug,
    active: item.is_active
  };
}