const https = require("https");
const { parseStringPromise } = require("xml2js");
const config = require("../config");

// API Request Counter (resets daily)
const stats = {
  requestsToday: 0,
  textsToday: 0,
  lastResetDate: new Date().toDateString(),
};

/**
 * Prüft ob der Zähler zurückgesetzt werden muss (neuer Tag)
 */
function checkAndResetDailyStats() {
  const today = new Date().toDateString();
  if (stats.lastResetDate !== today) {
    console.log(`[Scriptalizer] 📅 New day detected, resetting counters`);
    console.log(`[Scriptalizer] 📊 Yesterday's stats: ${stats.requestsToday} API calls, ${stats.textsToday} texts processed`);
    stats.requestsToday = 0;
    stats.textsToday = 0;
    stats.lastResetDate = today;
  }
}

/**
 * Gibt die aktuellen Stats zurück
 */
function getStats() {
  checkAndResetDailyStats();
  return { ...stats };
}

/**
 * Ruft die Scriptalizer API auf
 * @param {string} inputText - Text zum Scriptalisieren
 * @param {string} fontName - Font-Name (z.B. 'PremiumUltra79')
 * @param {number} errFrequency - Fehlerfrequenz
 * @returns {Promise<{status: string, outputText: string}>}
 */
async function callScriptalizer(inputText, fontName, errFrequency = 10) {
  // Prüfe ob neuer Tag
  checkAndResetDailyStats();

  return new Promise((resolve, reject) => {
    if (!config.scriptalizer.licenseKey) {
      reject(new Error("Scriptalizer License Key fehlt in Konfiguration"));
      return;
    }

    // Use x-www-form-urlencoded format
    const params = new URLSearchParams();
    params.append("LicenseKey", config.scriptalizer.licenseKey);
    params.append("FontName", fontName);
    params.append("ErrFrequency", String(errFrequency));
    params.append("InputText", inputText);

    const body = params.toString();

    // Check input size (48KB limit)
    if (Buffer.byteLength(body) > config.scriptalizer.maxInputSize) {
      reject(
        new Error(
          `Input size exceeds 48KB limit (${Buffer.byteLength(body)} bytes)`
        )
      );
      return;
    }

    const options = {
      hostname: "www.scriptalizer.co.uk",
      port: 443,
      path: "/QuantumScriptalize.asmx/Scriptalize",
      method: "POST",
      headers: {
        "Content-Type": "application/x-www-form-urlencoded; charset=utf-8",
        "Content-Length": Buffer.byteLength(body),
      },
      timeout: 30000, // 30 second timeout
    };

    const req = https.request(options, (res) => {
      let data = "";

      res.on("data", (chunk) => {
        data += chunk;
      });

      res.on("end", async () => {
        try {
          const result = await parseStringPromise(data, {
            explicitArray: false,
          });
          const response = result.ScriptalizerResponse;

          if (!response || response.Status !== "OK") {
            reject(new Error(response?.Status || "UNKNOWN_STATUS"));
            return;
          }

          // Zähler erhöhen bei erfolgreichem Request
          stats.requestsToday++;
          console.log(`[Scriptalizer] 📊 API Request #${stats.requestsToday} today completed`);

          resolve({ status: "OK", outputText: response.OutputText });
        } catch (err) {
          reject(
            new Error(`Failed to parse Scriptalizer response: ${err.message}`)
          );
        }
      });
    });

    req.on("error", (err) => {
      reject(new Error(`Scriptalizer request failed: ${err.message}`));
    });

    req.on("timeout", () => {
      req.destroy();
      reject(new Error("Scriptalizer request timed out"));
    });

    req.write(body);
    req.end();
  });
}

/**
 * Scriptalisiert mehrere Texte in 25er Batches
 * @param {string[]} texts - Array von Texten
 * @param {string} font - Font-Key (tilda, alva, ellie)
 * @param {number} errFrequency - Fehlerfrequenz
 * @returns {Promise<string[]>} - Array von scriptalisierten Texten
 */
async function scriptalizeBatch(texts, font = "tilda", errFrequency = 10) {
  if (!Array.isArray(texts) || texts.length === 0) {
    return [];
  }

  const fontName =
    config.scriptalizer.fontMap[font.toLowerCase()] ||
    config.scriptalizer.fontMap.tilda;
  const separator = config.scriptalizer.separator;
  const BATCH_SIZE = 18; // Zusätzlicher Deckel: max. 18 Texte pro Call (unabhängig von der Länge).
  // Primäre Grenze ist die ZEICHENLÄNGE: die Scriptalizer-API begrenzt den
  // InputText auf 32000 Zeichen pro Call ("Input length limit 32000 exceeded").
  // Fixe 18er-Batches sprengen das bei langen (mehrseitigen) Texten – daher nach
  // kumulativer Länge batchen, mit Sicherheitsabstand.
  const MAX_BATCH_CHARS = 28000;
  const sepLen = separator.length;

  // Batches nach Länge (und max. Anzahl) bilden.
  const batches = [];
  {
    let cur = [];
    let curLen = 0;
    for (const t of texts) {
      const tLen = String(t || "").length;
      const projected = curLen + (cur.length ? sepLen : 0) + tLen;
      if (cur.length && (projected > MAX_BATCH_CHARS || cur.length >= BATCH_SIZE)) {
        batches.push(cur);
        cur = [];
        curLen = 0;
      }
      cur.push(t);
      curLen += (cur.length > 1 ? sepLen : 0) + tLen;
    }
    if (cur.length) batches.push(cur);
  }

  const totalBatches = batches.length;
  console.log(
    `[Scriptalizer] Processing ${texts.length} texts in ${totalBatches} batch(es) (max ${BATCH_SIZE} texts / ${MAX_BATCH_CHARS} chars each)`
  );

  const allScriptalized = [];

  for (let b = 0; b < batches.length; b += 1) {
    const batch = batches[b];
    const batchNumber = b + 1;
    const combinedText = batch.join(separator);

    console.log(
      `[Scriptalizer] Processing batch ${batchNumber}/${totalBatches} (${batch.length} texts, ${combinedText.length} chars)`
    );

    try {
      const result = await callScriptalizer(
        combinedText,
        fontName,
        errFrequency
      );

      // Trenne Ergebnis wieder
      const scriptalized = result.outputText.split(separator);

      if (scriptalized.length !== batch.length) {
        console.warn(
          `[Scriptalizer] Batch ${batchNumber}: returned ${scriptalized.length} parts, expected ${batch.length}`
        );
      }

      allScriptalized.push(...scriptalized);
      console.log(
        `[Scriptalizer] Batch ${batchNumber}/${totalBatches} completed successfully`
      );
    } catch (err) {
      console.error(`[Scriptalizer] Batch ${batchNumber} failed:`, err.message);
      throw err;
    }
  }

  // Textzähler erhöhen
  stats.textsToday += allScriptalized.length;

  console.log(
    `[Scriptalizer] All batches completed. Total scriptalized: ${allScriptalized.length}`
  );
  console.log(
    `[Scriptalizer] 📊 Daily stats: ${stats.requestsToday} API calls, ${stats.textsToday} texts processed`
  );
  return allScriptalized;
}

/**
 * Scriptalisiert einen einzelnen Text
 * @param {string} text - Text zum Scriptalisieren
 * @param {string} font - Font-Key (tilda, alva, ellie)
 * @param {number} errFrequency - Fehlerfrequenz
 * @returns {Promise<string>} - Scriptalisierter Text
 */
async function scriptalizeSingle(text, font = "tilda", errFrequency = 10) {
  const fontName =
    config.scriptalizer.fontMap[font.toLowerCase()] ||
    config.scriptalizer.fontMap.tilda;

  try {
    const result = await callScriptalizer(text, fontName, errFrequency);
    return result.outputText;
  } catch (err) {
    console.error("Scriptalizer single call failed:", err.message);
    throw err;
  }
}

module.exports = {
  scriptalizeBatch,
  scriptalizeSingle,
  getStats,
};