import type { Children } from "@alloy-js/core";
import {
  Declaration as CoreDeclaration,
  createSymbolSlot,
  Name,
  Show,
} from "@alloy-js/core";

import { useTSNamePolicy } from "../name-policy.js";
import { createValueSymbol } from "../symbols/index.js";
import { TSSymbolFlags } from "../symbols/ts-output-symbol.js";
import type { CommonDeclarationProps } from "./Declaration.js";
import { JSDoc } from "./JSDoc.jsx";
import { TypeRefContext } from "./TypeRefContext.jsx";

export interface VarDeclarationProps extends CommonDeclarationProps {
  const?: boolean;
  let?: boolean;
  var?: boolean;
  initializer?: Children;
  type?: Children;
  nullish?: boolean;
}

export function VarDeclaration(props: VarDeclarationProps) {
  const TypeSymbolSlot = createSymbolSlot();
  const ValueTypeSymbolSlot = createSymbolSlot();
  const sym = createValueSymbol(props.name, {
    refkeys: props.refkey,
    default: props.default,
    export: props.export,
    metadata: props.metadata,
    tsFlags: props.nullish ? TSSymbolFlags.Nullish : TSSymbolFlags.None,
    type: props.type ? TypeSymbolSlot.firstSymbol : undefined,
    namePolicy: useTSNamePolicy().for("variable"),
  });

  if (!props.type) {
    ValueTypeSymbolSlot.moveMembersTo(sym);
  }

  const keyword = props.var ? "var" : props.let ? "let" : "const";
  const type = props.type ? (
    <TypeRefContext>
      : <TypeSymbolSlot>{props.type}</TypeSymbolSlot>
    </TypeRefContext>
  ) : undefined;

  return (
    <>
      <Show when={Boolean(props.doc)}>
        <JSDoc children={props.doc} />
        <hbr />
      </Show>
      <CoreDeclaration symbol={sym}>
        {props.export ? "export " : ""}
        {props.default ? "default " : ""}
        <Show when={!props.default}>
          {keyword} <Name />
          {type}
          <Show when={Boolean(props.initializer || props.children)}>
            {" = "}
          </Show>
        </Show>
        <ValueTypeSymbolSlot>
          {props.initializer ?? props.children}
        </ValueTypeSymbolSlot>
      </CoreDeclaration>
    </>
  );
}