/**
 * Journal completions — client-side loader for /__COMPLETIONS.json
 *
 * In CLI mode, fetches the pre-computed index. In dev/browser mode, falls
 * back to scanning the in-memory file index for dice expressions, headings,
 * and declare blocks.
 *
 * The fetch runs eagerly on module import. Call `useJournalCompletions()`
 * from any Solid component to reactively read the state.
 */

import { createSignal } from "solid-js";
import {
  getPathsByExtension,
  getIndexedData,
  setIndexedData,
  setInlineResolver,
} from "../../data-loader/file-index";
import {
  buildRegistryFromIndex,
  deriveCompletions,
  resolveInlineByPath,
  type ContentRegistry,
} from "../../cli/content-registry";
import type {
  CompletionsPayload,
  DiceCompletion,
  LinkCompletion,
  SparkTableCompletion,
  VarDeclaration,
  TagModifier,
} from "../../cli/completions/types";
import { initReactivity, computeInitialValues } from "./var-reactivity";
import { sendMessage, journalStreamState } from "../stores/journalStream";

export type { VarDeclaration, TagModifier };

// Re-export CLI types so consumers don't need to know about the CLI path
export type { DiceCompletion, LinkCompletion, SparkTableCompletion };

/** Convenience alias — same shape as the CLI's CompletionsPayload. */
export type JournalCompletions = CompletionsPayload;

export type CompletionsState =
  | { status: "loading" }
  | { status: "loaded"; data: JournalCompletions }
  | { status: "empty" }
  | { status: "error"; message: string };

// ------------------- Reactive state (module-level signal) -------------------

const [completionsState, setCompletionsState] = createSignal<CompletionsState>({
  status: "loading",
});

// The registry backing the completions. Populated in both CLI and client
// modes so inline content ids can be resolved at runtime (e.g. spark rolls).
let activeRegistry: ContentRegistry = { pathIndex: {}, docContent: {} };

/**
 * The registry backing the current completions.
 * In CLI mode this is fetched from the server; in browser mode it is built
 * client-side. Used to resolve inline content ids (e.g. spark table CSVs).
 */
export function getRegistry(): ContentRegistry {
  return activeRegistry;
}

// Register the inline-content resolver so `getIndexedData` can resolve
// directive refs (e.g. `./csv_abc123`) that aren't real files.
setInlineResolver((path) => resolveInlineByPath(activeRegistry, path));

// ------------------- Fetch (CLI mode) -------------------

async function tryServer(): Promise<JournalCompletions | null> {
  try {
    const resp = await fetch("/__COMPLETIONS.json");
    if (!resp.ok) return null;
    const data = await resp.json();
    return {
      dice: Array.isArray(data.dice) ? data.dice : [],
      links: Array.isArray(data.links) ? data.links : [],
      sparkTables: Array.isArray(data.sparkTables) ? data.sparkTables : [],
      declarations: Array.isArray(data.declarations) ? data.declarations : [],
      tagModifiers: Array.isArray(data.tagModifiers) ? data.tagModifiers : [],
    };
  } catch {
    return null;
  }
}

/** Load the content registry from the server (CLI mode). */
async function tryServerRegistry(): Promise<void> {
  try {
    const resp = await fetch("/__CONTENT_REGISTRY.json");
    if (!resp.ok) return;
    const data = await resp.json();
    activeRegistry = {
      pathIndex: data.pathIndex ?? {},
      docContent: data.docContent ?? {},
    };
  } catch {
    // Registry unavailable — leave empty; client scan will populate it.
  }
}

// ------------------- Client-side fallback scan -------------------

async function scanClientSide(): Promise<JournalCompletions> {
  const paths = await getPathsByExtension("md");

  // Load all .md content into a raw index, then build the registry through
  // the same shared pipeline as the CLI (scanDoc + spark injection).
  const index: Record<string, string> = {};
  for (const filePath of paths) {
    const content = await getIndexedData(filePath);
    if (!content) continue;
    index[filePath] = content;
  }

  const registry = buildRegistryFromIndex(index);
  activeRegistry = registry;

  // Write the processed (stripped) content back into the file index so
  // Article/md-embed render the same content as CLI mode (spark tables
  // coerced, attributed blocks processed, data-spark injected).
  for (const [path, content] of Object.entries(registry.pathIndex)) {
    setIndexedData(path, content);
  }

  return deriveCompletions(registry);
}

// ------------------- Init (runs eagerly at import time) -------------------

// Using a top-level IIFE so the promise starts immediately
const _initPromise: Promise<void> = (async () => {
  // 1. Try server first (CLI mode)
  const serverData = await tryServer();
  if (serverData) {
    setCompletionsState({ status: "loaded", data: serverData });
    await tryServerRegistry();
    try {
      initReactivity({
        declarations: serverData.declarations,
        tagModifiers: serverData.tagModifiers,
      });
      seedDeclaredVariables();
    } catch (e) {
      console.warn("[completions] reactivity init error:", e);
    }
    return;
  }

  // 2. Fall back to client-side scan (dev/browser mode)
  try {
    const data = await scanClientSide();
    if (data.dice.length > 0 || data.links.length > 0) {
      setCompletionsState({ status: "loaded", data });
      try {
        initReactivity({
          declarations: data.declarations,
          tagModifiers: data.tagModifiers,
        });
        seedDeclaredVariables();
      } catch (e) {
        console.warn("[completions] reactivity init error:", e);
      }
    } else {
      setCompletionsState({ status: "empty" });
    }
  } catch (e) {
    setCompletionsState({
      status: "error",
      message: e instanceof Error ? e.message : "Failed to scan",
    });
  }
})();

// ------------------- Public API -------------------

/**
 * Returns a Promise that resolves once completions are loaded (or failed).
 * Useful for waiting before showing the completions dropdown.
 */
export function ensureCompletions(): Promise<void> {
  return _initPromise;
}

/**
 * Reactive hooks for the journal input.
 * Returns the current completions state + a convenience `data` extractor.
 */
export function useJournalCompletions(): {
  state: CompletionsState;
  data: JournalCompletions;
} {
  const s = completionsState();
  if (s.status === "loaded") {
    return { state: s, data: s.data };
  }
  return {
    state: s,
    data: {
      dice: [],
      links: [],
      sparkTables: [],
      declarations: [],
      tagModifiers: [],
    },
  };
}

// ---------------------------------------------------------------------------
// Seed declared variables into the store on load
// ---------------------------------------------------------------------------

function seedDeclaredVariables(): void {
  const initial = computeInitialValues(journalStreamState.variables);
  for (const { key, value } of initial) {
    sendMessage("var", { action: "set", key, value });
  }
}