'use strict';

/**
 * Nur für Tests: Appwrite im Speicher (Teilmenge der REST-API von 1.8.1) als echter HTTP-Server auf Port 0.
 *
 *   GET    /v1/account                                   Header X-Appwrite-JWT (+ Projekt, ohne Key)
 *   GET|POST /v1/tablesdb/{db}/tables/{t}/rows            POST {rowId, data, permissions}; doppelt -> 409
 *   GET|PATCH|DELETE .../rows/{id}                        PATCH {data?, permissions?}
 *   GET|PUT|DELETE /v1/storage/buckets/{b}/files/{f}      PUT {permissions}
 *   GET /v1/storage/buckets/{b}/files/{f}/view            Dateiinhalt (Bytes aus `content`)
 *
 * Die Tabelle `cards` ist nur zum Lesen da (Zeilen legt der Test mit `addCard` an). Es gibt außerdem die Tabellen
 * `gallery`, `reports`, `logos`, `logo_likes` und `logo_reports` und die Buckets `gallery-images`, `card-images`, `logo-images`.
 *
 * Abfragen: `queries[]=<json>` mit den Methoden equal, cursorAfter und limit. Die Antwort enthält wie bei Appwrite `total`:
 * die Zahl aller Treffer der equal-Abfragen, unabhängig von limit und cursorAfter (darauf baut `countRows`).
 * Zeilen werden gegen die Spaltenlängen der echten Tabellen geprüft (document_invalid_structure), damit zu lange Werte im
 * Test auffallen.
 * Dateien werden nach ID gesucht und liefern ihren echten `bucketId` zurück (der Bucket in der URL zählt nicht),
 * so lässt sich der Fall „Datei liegt in einem anderen Bucket“ nachstellen.
 */

const http = require('node:http');

const BUCKETS = ['gallery-images', 'card-images', 'logo-images'];

/** PNG-Anfang (Signatur + IHDR) mit den Maßen; reicht für die Größenprüfung der API. */
function pngHeader(width, height) {
  const head = Buffer.alloc(33);
  Buffer.from([0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a]).copy(head, 0);
  head.writeUInt32BE(13, 8);
  head.write('IHDR', 12, 'latin1');
  head.writeUInt32BE(width, 16);
  head.writeUInt32BE(height, 20);
  head[24] = 8; // Bit-Tiefe
  head[25] = 6; // RGBA
  return head;
}

/** WebP-Anfang mit den Maßen; kind: 'VP8 ' (verlustbehaftet), 'VP8L' (verlustfrei) oder 'VP8X' (erweitert). */
function webpHeader(kind, width, height) {
  const head = Buffer.alloc(40);
  head.write('RIFF', 0, 'latin1');
  head.writeUInt32LE(32, 4);
  head.write('WEBP', 8, 'latin1');
  head.write(kind, 12, 'latin1');
  if (kind === 'VP8 ') {
    head.writeUInt32LE(10, 16);
    Buffer.from([0x30, 0x01, 0x00, 0x9d, 0x01, 0x2a]).copy(head, 20);
    head.writeUInt16LE(width & 0x3fff, 26);
    head.writeUInt16LE(height & 0x3fff, 28);
  } else if (kind === 'VP8L') {
    head.writeUInt32LE(5, 16);
    head[20] = 0x2f;
    head.writeUInt32LE(((width - 1) & 0x3fff) | (((height - 1) & 0x3fff) << 14), 21);
  } else if (kind === 'VP8X') {
    head.writeUInt32LE(10, 16);
    head[20] = 0x10; // Alpha-Flag
    head.writeUIntLE(width - 1, 24, 3);
    head.writeUIntLE(height - 1, 27, 3);
  } else {
    throw new Error(`Unbekannte WebP-Art: ${kind}`);
  }
  return head;
}

const COLUMNS = {
  gallery: {
    title: { size: 60, required: true },
    issuer: { size: 40 },
    tags: { size: 120 },
    displayName: { size: 30 },
    imageFileId: { size: 36, required: true },
    previewFileId: { size: 36, required: true },
    sourceCardId: { size: 36 },
    ownerId: { size: 36, required: true },
    hidden: { type: 'boolean' },
    reportCount: { type: 'integer' },
    searchText: { size: 300 },
  },
  reports: {
    galleryId: { size: 36, required: true },
    reason: { enum: ['unangemessen', 'kartendaten', 'urheberrecht', 'spam', 'sonstiges'], required: true },
    reporterHash: { size: 64, required: true },
  },
  // Spalten wie in web/scripts/appwrite-setup.mjs (Community-Logos)
  logos: {
    name: { size: 40, required: true },
    displayName: { size: 30 },
    fileId: { size: 36, required: true },
    ownerId: { size: 36, required: true },
    mono: { type: 'boolean' },
    likeCount: { type: 'integer', min: 0 },
    hidden: { type: 'boolean' },
    reportCount: { type: 'integer', min: 0 },
  },
  logo_likes: {
    logoId: { size: 36, required: true },
    userId: { size: 36, required: true },
  },
  logo_reports: {
    logoId: { size: 36, required: true },
    reason: { enum: ['unangemessen', 'kartendaten', 'urheberrecht', 'spam', 'sonstiges'], required: true },
    reporterHash: { size: 64, required: true },
  },
};

/** Standardwerte der Spalten, die Appwrite beim Anlegen einsetzt, wenn die Anfrage sie weglässt. */
const DEFAULTS = {
  gallery: { hidden: false, reportCount: 0 },
  logos: { mono: false, likeCount: 0, hidden: false, reportCount: 0 },
};

async function startFakeAppwrite({ project = 'proj-test', key = 'KEY-test-secret-value', database = 'aircard' } = {}) {
  const tables = {
    gallery: new Map(),
    reports: new Map(),
    cards: new Map(),
    logos: new Map(),
    logo_likes: new Map(),
    logo_reports: new Map(),
  };
  const files = new Map();
  const contents = new Map();
  const users = new Map();
  const calls = [];
  const injections = [];
  let sequence = 0;

  function addUser(jwt, { id, labels = [] }) {
    users.set(jwt, { $id: id, email: `${id}@example.test`, labels });
  }

  /** Beliebige Konto-Antwort für `GET /account` (z. B. ohne labels oder mit ungültiger ID). */
  function addRawUser(jwt, account) {
    users.set(jwt, account);
  }

  /**
   * Datei mit Metadaten und Inhalt. `role` bestimmt den Standardinhalt: 'image' = Kartenbild 1536 x 969, 'preview' =
   * Vorschau 480 x 303 (Standard: WebP ist die Vorschau, alles andere das Bild); `content` überschreibt ihn.
   */
  function addFile({ id, bucket = 'gallery-images', owner, permissions, mimeType = 'image/png', size = 1000, role, content }) {
    const kind = role || (mimeType === 'image/webp' ? 'preview' : 'image');
    const [width, height] = kind === 'preview' ? [480, 303] : [1536, 969];
    files.set(id, {
      $id: id,
      bucketId: bucket,
      name: `${id}.png`,
      $permissions: permissions || ['read("any")', `delete("user:${owner}")`],
      mimeType,
      sizeOriginal: size,
    });
    contents.set(id, content || (mimeType === 'image/webp' ? webpHeader('VP8 ', width, height) : pngHeader(width, height)));
  }

  /** Private Karte (Tabelle `cards`) mit den Rechten, die Appwrite dem Besitzer beim Anlegen gibt. */
  function addCard(id, owner, permissions) {
    return addRow('cards', id, { name: 'Karte' }, permissions || [`read("user:${owner}")`, `update("user:${owner}")`, `delete("user:${owner}")`]);
  }

  function addRow(table, id, data, permissions) {
    const row = { $id: id, $createdAt: new Date(1_700_000_000_000 + (++sequence) * 1000).toISOString(), $permissions: permissions, ...data };
    tables[table].set(id, row);
    return row;
  }

  /** Nächster passender Aufruf (predicate(call) -> boolean) scheitert mit Status/Typ. */
  function failNext(predicate, { status = 500, type = 'general_server_error' } = {}) {
    injections.push({ predicate, status, type, hang: false });
  }

  /** Nächster passender Aufruf bekommt nie eine Antwort. */
  function hangNext(predicate) {
    injections.push({ predicate, hang: true });
  }

  /** Nächster passender Aufruf wird erst nach `delayMs` bearbeitet (Zustand ändert sich erst dann). */
  function delayNext(predicate, delayMs) {
    injections.push({ predicate, delayMs });
  }

  function validateData(table, data, { partial }) {
    const columns = COLUMNS[table];
    for (const [name, value] of Object.entries(data)) {
      const column = columns[name];
      if (!column) return `Unknown attribute: ${name}`;
      if (column.type === 'boolean' && typeof value !== 'boolean') return `Invalid ${name}`;
      if (column.type === 'integer' && (!Number.isInteger(value) || (column.min !== undefined && value < column.min))) return `Invalid ${name}`;
      if (column.enum && !column.enum.includes(value)) return `Invalid ${name}`;
      if (column.size !== undefined) {
        if (typeof value !== 'string') return `Invalid ${name}`;
        if (value.length > column.size) return `Invalid ${name}: too long`;
      }
    }
    if (!partial) {
      for (const [name, column] of Object.entries(columns)) {
        if (column.required && data[name] === undefined) return `Missing required attribute: ${name}`;
      }
    }
    return null;
  }

  const server = http.createServer((req, res) => {
    const chunks = [];
    req.on('data', (chunk) => chunks.push(chunk));
    req.on('end', async () => {
      const raw = Buffer.concat(chunks).toString('utf8');
      const [pathname, search = ''] = req.url.split('?');
      const call = {
        method: req.method,
        path: pathname,
        search,
        headers: req.headers,
        body: raw === '' ? null : safeParse(raw),
      };
      calls.push(call);

      const reply = (status, payload) => {
        if (status === 204) {
          res.writeHead(204);
          res.end();
          return;
        }
        const text = JSON.stringify(payload);
        res.writeHead(status, { 'Content-Type': 'application/json', 'Content-Length': Buffer.byteLength(text) });
        res.end(text);
      };
      const error = (status, type, message = type) => reply(status, { message, code: status, type });

      const injectionIndex = injections.findIndex((entry) => entry.predicate(call));
      if (injectionIndex !== -1) {
        const [entry] = injections.splice(injectionIndex, 1);
        if (entry.hang) return;
        if (entry.delayMs) {
          await new Promise((resolve) => setTimeout(resolve, entry.delayMs));
        } else {
          return error(entry.status, entry.type);
        }
      }

      const segments = pathname.split('/').filter(Boolean).map(decodeSegment);
      if (segments[0] !== 'v1' || req.headers['x-appwrite-project'] !== project) {
        return error(401, 'general_unauthorized_scope', 'Missing or wrong project');
      }

      // GET /v1/account (JWT, ohne Key)
      if (segments.length === 2 && segments[1] === 'account' && req.method === 'GET') {
        const user = users.get(req.headers['x-appwrite-jwt']);
        if (!user) return error(401, 'user_jwt_invalid', 'Invalid JWT');
        return reply(200, user);
      }

      if (req.headers['x-appwrite-key'] !== key) return error(401, 'general_unauthorized_scope', 'Missing or wrong key');

      // Zeilen
      if (segments[1] === 'tablesdb' && segments[3] === 'tables' && segments[5] === 'rows') {
        const table = segments[4];
        if (segments[2] !== database) return error(404, 'database_not_found');
        if (!tables[table]) return error(404, 'table_not_found');
        const store = tables[table];

        if (segments.length === 6 && req.method === 'POST') {
          const body = call.body || {};
          if (typeof body.rowId !== 'string' || body.rowId === '') return error(400, 'general_argument_invalid', 'rowId is required');
          if (store.has(body.rowId)) return error(409, 'row_already_exists');
          const data = body.data || {};
          const problem = validateData(table, data, { partial: false });
          if (problem) return error(400, 'document_invalid_structure', problem);
          const row = addRow(table, body.rowId, { ...DEFAULTS[table], ...data }, body.permissions || []);
          return reply(201, row);
        }

        if (segments.length === 6 && req.method === 'GET') {
          const found = runQueries([...store.values()], search);
          if (found === null) return error(400, 'general_query_invalid');
          return reply(200, found);
        }

        if (segments.length === 7) {
          const row = store.get(segments[6]);
          if (!row) return error(404, 'row_not_found');
          if (req.method === 'GET') return reply(200, row);
          if (req.method === 'DELETE') {
            store.delete(segments[6]);
            return reply(204);
          }
          if (req.method === 'PATCH') {
            const body = call.body || {};
            const data = body.data || {};
            const problem = validateData(table, data, { partial: true });
            if (problem) return error(400, 'document_invalid_structure', problem);
            Object.assign(row, data);
            if (Array.isArray(body.permissions)) row.$permissions = body.permissions;
            return reply(200, row);
          }
        }
      }

      // Dateiinhalt: GET .../files/{id}/view
      if (segments[1] === 'storage' && segments[2] === 'buckets' && segments[4] === 'files' && segments.length === 7 && segments[6] === 'view' && req.method === 'GET') {
        if (!BUCKETS.includes(segments[3])) return error(404, 'storage_bucket_not_found');
        const file = files.get(segments[5]);
        if (!file) return error(404, 'storage_file_not_found');
        const content = contents.get(segments[5]);
        res.writeHead(200, { 'Content-Type': file.mimeType, 'Content-Length': content.length });
        res.end(content);
        return;
      }

      // Dateien
      if (segments[1] === 'storage' && segments[2] === 'buckets' && segments[4] === 'files' && segments.length === 6) {
        if (!BUCKETS.includes(segments[3])) return error(404, 'storage_bucket_not_found');
        const file = files.get(segments[5]);
        if (!file) return error(404, 'storage_file_not_found');
        if (req.method === 'GET') return reply(200, file);
        if (req.method === 'DELETE') {
          files.delete(segments[5]);
          contents.delete(segments[5]);
          return reply(204);
        }
        if (req.method === 'PUT') {
          const body = call.body || {};
          if (!Array.isArray(body.permissions)) return error(400, 'general_argument_invalid');
          file.$permissions = body.permissions;
          return reply(200, file);
        }
      }

      return error(404, 'general_route_not_found');
    });
  });

  await new Promise((resolve) => server.listen(0, '127.0.0.1', resolve));
  const { port } = server.address();

  return {
    url: `http://127.0.0.1:${port}`,
    endpoint: `http://127.0.0.1:${port}/v1`,
    project,
    key,
    calls,
    addUser,
    addRawUser,
    addFile,
    addCard,
    addRow,
    failNext,
    hangNext,
    delayNext,
    row: (table, id) => tables[table].get(id) || null,
    rows: (table) => [...tables[table].values()],
    file: (id) => files.get(id) || null,
    close: async () => {
      server.closeAllConnections();
      await new Promise((resolve) => server.close(resolve));
    },
  };
}

function decodeSegment(segment) {
  try {
    return decodeURIComponent(segment);
  } catch {
    return segment;
  }
}

function safeParse(text) {
  try {
    return JSON.parse(text);
  } catch {
    return { _unparsable: text };
  }
}

/**
 * Wendet equal, cursorAfter und limit an (Reihenfolge = Anlegereihenfolge); null bei unbekannter Abfrage.
 * Liefert {total, rows}: `total` zählt alle Treffer der equal-Abfragen, `rows` ist die Seite nach cursorAfter und limit.
 */
function runQueries(rows, search) {
  let result = rows;
  let limit = 25;
  let cursor = null;
  for (const part of search.split('&').filter(Boolean)) {
    const eq = part.indexOf('=');
    const name = decodeURIComponent(part.slice(0, eq));
    if (name !== 'queries[]') return null;
    let query;
    try {
      query = JSON.parse(decodeURIComponent(part.slice(eq + 1)));
    } catch {
      return null;
    }
    if (query.method === 'equal') {
      result = result.filter((row) => query.values.includes(row[query.attribute]));
    } else if (query.method === 'limit') {
      limit = query.values[0];
    } else if (query.method === 'cursorAfter') {
      cursor = query.values[0];
    } else {
      return null;
    }
  }
  const total = result.length;
  if (cursor !== null) {
    const index = result.findIndex((row) => row.$id === cursor);
    if (index === -1) return null;
    result = result.slice(index + 1);
  }
  return { total, rows: result.slice(0, limit) };
}

module.exports = { startFakeAppwrite, pngHeader, webpHeader };