/**
 * Data layer for the Disclosure Bureau wiki.
 *
 * Reads markdown files directly from /Users/guto/ufo/wiki and /Users/guto/ufo/processing.
 * No database — markdown IS the database (Karpathy LLM-wiki pattern).
 */
import fs from "node:fs/promises";
import path from "node:path";
import matter from "gray-matter";

export const UFO_ROOT = process.env.UFO_ROOT ?? "/Users/guto/ufo";
export const WIKI = path.join(UFO_ROOT, "wiki");
export const PROCESSING = path.join(UFO_ROOT, "processing");

export type EntityClass =
  | "people"
  | "organizations"
  | "locations"
  | "events"
  | "uap-objects"
  | "vehicles"
  | "operations"
  | "concepts";

export interface Frontmatter {
  [key: string]: unknown;
}

export interface MdFile {
  fm: Frontmatter;
  body: string;
}

export async function readMd(absPath: string): Promise<MdFile> {
  const raw = await fs.readFile(absPath, "utf-8");
  const parsed = matter(raw);
  return { fm: parsed.data as Frontmatter, body: parsed.content };
}

export async function safeReadMd(absPath: string): Promise<MdFile | null> {
  try {
    return await readMd(absPath);
  } catch {
    return null;
  }
}

export async function listDocuments(): Promise<string[]> {
  const docsDir = path.join(WIKI, "documents");
  try {
    const files = await fs.readdir(docsDir);
    return files
      .filter((f) => f.endsWith(".md"))
      .map((f) => f.replace(/\.md$/, ""))
      .sort();
  } catch {
    return [];
  }
}

export async function readDocument(docId: string): Promise<MdFile | null> {
  return safeReadMd(path.join(WIKI, "documents", `${docId}.md`));
}

export async function listPages(docId: string): Promise<string[]> {
  const dir = path.join(WIKI, "pages", docId);
  try {
    const files = await fs.readdir(dir);
    return files
      .filter((f) => /^p\d{3}\.md$/.test(f))
      .map((f) => f.replace(/\.md$/, ""))
      .sort();
  } catch {
    return [];
  }
}

export async function readPage(docId: string, pageStem: string): Promise<MdFile | null> {
  return safeReadMd(path.join(WIKI, "pages", docId, `${pageStem}.md`));
}

export async function readOcr(docId: string, pageNum: number): Promise<string | null> {
  const padded = String(pageNum).padStart(3, "0");
  const ocrPath = path.join(PROCESSING, "ocr", docId, `p-${padded}.txt`);
  try {
    return await fs.readFile(ocrPath, "utf-8");
  } catch {
    return null;
  }
}

export async function readEntity(cls: EntityClass, id: string): Promise<MdFile | null> {
  return safeReadMd(path.join(WIKI, "entities", cls, `${id}.md`));
}

export async function readVideo(id: string): Promise<MdFile | null> {
  return safeReadMd(path.join(WIKI, "videos", `${id}.md`));
}

export async function readImageDirect(id: string): Promise<MdFile | null> {
  return safeReadMd(path.join(WIKI, "images-direct", `${id}.md`));
}

export async function readTable(tableId: string): Promise<{ md: MdFile | null; csv: string[][] | null }> {
  const md = await safeReadMd(path.join(WIKI, "tables", `${tableId}.md`));
  const csvPath = path.join(PROCESSING, "tables", `${tableId}.csv`);
  let csv: string[][] | null = null;
  try {
    const raw = await fs.readFile(csvPath, "utf-8");
    csv = parseCsv(raw);
  } catch {}
  return { md, csv };
}

function parseCsv(text: string): string[][] {
  // Minimal CSV parser with quoted-field support
  const rows: string[][] = [];
  let row: string[] = [];
  let field = "";
  let inQ = false;
  for (let i = 0; i < text.length; i++) {
    const c = text[i];
    if (inQ) {
      if (c === '"' && text[i + 1] === '"') {
        field += '"';
        i++;
      } else if (c === '"') {
        inQ = false;
      } else {
        field += c;
      }
    } else {
      if (c === '"') inQ = true;
      else if (c === ",") {
        row.push(field);
        field = "";
      } else if (c === "\n") {
        row.push(field);
        rows.push(row);
        row = [];
        field = "";
      } else if (c === "\r") {
        // skip
      } else {
        field += c;
      }
    }
  }
  if (field.length > 0 || row.length > 0) {
    row.push(field);
    rows.push(row);
  }
  return rows;
}

export function entityClassFromPath(filePath: string): EntityClass | null {
  const m = filePath.match(/entities\/(people|organizations|locations|events|uap-objects|vehicles|operations|concepts)\//);
  return m ? (m[1] as EntityClass) : null;
}

export function classKeyToFolder(key: string): EntityClass | null {
  const map: Record<string, EntityClass> = {
    person: "people",
    people: "people",
    organization: "organizations",
    organizations: "organizations",
    location: "locations",
    locations: "locations",
    event: "events",
    events: "events",
    uap_object: "uap-objects",
    "uap-object": "uap-objects",
    "uap-objects": "uap-objects",
    vehicle: "vehicles",
    vehicles: "vehicles",
    operation: "operations",
    operations: "operations",
    concept: "concepts",
    concepts: "concepts",
  };
  return map[key] ?? null;
}