import axios from 'axios';
import https from 'https';
import fs from 'fs';
import readline from 'readline';
import path from 'path';
import { fileURLToPath } from 'url';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

// ─── CONFIG ────────────────────────────────────────────────────────

const API_VERSION = '2025-10';
const exportDir = path.join(__dirname, '..', 'exports');
const logDir = path.join(__dirname, '..', 'logs');
const logFilePath = path.join(logDir, 'BulkInventorySyncJob.log');
const JSONL_FILENAME = 'inventory_data.jsonl';
const BATCH_SIZE = 1000;

// ─── HELPERS ───────────────────────────────────────────────────────

function ensureDir(dir) {
  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
}

function chunkArray(array, size) {
  const result = [];
  for (let i = 0; i < array.length; i += size) {
    result.push(array.slice(i, i + size));
  }
  return result;
}

function timestamp() {
  return new Date().toISOString().replace(/[-:]/g, '').replace('T', '_').split('.')[0];
}

function logStep(step, message) {
  ensureDir(logDir);
  const logMessage = `[${new Date().toISOString()}] [${step}] ${message}`;
  console.log(logMessage);
  fs.appendFileSync(logFilePath, logMessage + '\n', 'utf8');
}

// ─── TURN14 TOKEN ──────────────────────────────────────────────────

async function getTurn14AccessToken(shop, accessToken) {
  const client = axios.create({
    baseURL: `https://${shop}/admin/api/${API_VERSION}/graphql.json`,
    headers: {
      'X-Shopify-Access-Token': accessToken,
      'Content-Type': 'application/json',
    },
  });

  const query = `{
    shop {
      id
      metafield(namespace: "turn14", key: "credentials") {
        value
      }
    }
  }`;

  const gqlRes = await client.post('', { query });
  const shopId = gqlRes.data?.data?.shop?.id;
  const raw = gqlRes.data?.data?.shop?.metafield?.value;

  if (!raw) {
    throw new Error('No Turn14 credentials found in Shopify metafield.');
  }

  let creds;
  try {
    creds = JSON.parse(raw);
  } catch {
    throw new Error('Malformed Turn14 credential metafield.');
  }

  logStep('1', `Turn14 credentials loaded from metafield (clientId: ${creds.clientId?.slice(0, 8)}...)`);

  const now = new Date();
  const expiresAt = creds.expiresAt ? new Date(creds.expiresAt) : new Date(0);
  const isExpired = now >= expiresAt;

  if (!isExpired && creds.accessToken) {
    logStep('1', 'Turn14 token is still valid, using cached token.');
    return creds.accessToken;
  }

  logStep('1', 'Turn14 token expired or missing. Refreshing...');

  const response = await axios.post(
    'https://turn14.data4autos.com/v1/auth/token',
    {
      grant_type: 'client_credentials',
      client_id: creds.clientId,
      client_secret: creds.clientSecret,
    },
    { headers: { 'Content-Type': 'application/json' } }
  );

  const newToken = response.data.access_token;
  if (!newToken) {
    throw new Error('Turn14 token refresh returned no access_token.');
  }

  const newExpiresAt = new Date(Date.now() + 3600 * 1000).toISOString();
  const newValue = JSON.stringify({
    clientId: creds.clientId,
    clientSecret: creds.clientSecret,
    accessToken: newToken,
    expiresAt: newExpiresAt,
  }).replace(/"/g, '\\"');

  const mutation = `
    mutation {
      metafieldsSet(metafields: [{
        ownerId: "${shopId}"
        namespace: "turn14"
        key: "credentials"
        type: "json"
        value: "${newValue}"
      }]) {
        userErrors { field message }
      }
    }
  `;

  const updateRes = await client.post('', { query: mutation });
  const userErrors = updateRes.data?.data?.metafieldsSet?.userErrors;
  if (userErrors?.length) {
    throw new Error(`Failed to update metafield: ${JSON.stringify(userErrors)}`);
  }

  logStep('1', '✅ Turn14 token refreshed and metafield updated.');
  return newToken;
}

// ─── SHOPIFY HELPERS ───────────────────────────────────────────────

async function getLocationID(shop, accessToken) {
  logStep('3', 'Fetching Shopify location ID...');
  const response = await axios.post(
    `https://${shop}/admin/api/${API_VERSION}/graphql.json`,
    { query: `{ locations(first: 10) { edges { node { id name } } } }` },
    { headers: { 'X-Shopify-Access-Token': accessToken } }
  );
  const locations = response.data.data.locations.edges;
  const locationId = locations[0].node.id;
  logStep('3', `✅ Location ID: ${locationId}`);
  return locationId;
}

async function startBulkExport(shop, accessToken) {
  logStep('4.1', 'Starting Shopify bulk product export...');
  const mutation = `
    mutation {
      bulkOperationRunQuery(
        query: """
        {
          products {
            edges {
              node {
                id
                handle
                variants {
                  edges {
                    node {
                      id
                      inventoryItem { id }
                    }
                  }
                }
              }
            }
          }
        }
        """
      ) {
        bulkOperation { id status }
        userErrors { field message code }
      }
    }
  `;

  const resp = await axios.post(
    `https://${shop}/admin/api/${API_VERSION}/graphql.json`,
    { query: mutation },
    { headers: { 'X-Shopify-Access-Token': accessToken } }
  );

  const err = resp.data.data.bulkOperationRunQuery.userErrors;
  if (err.length) throw new Error(JSON.stringify(err));

  logStep('4.1', `✅ Export started: ${resp.data.data.bulkOperationRunQuery.bulkOperation.id}`);
}

async function pollUntilReady(shop, accessToken) {
  const query = `{ currentBulkOperation { status url errorCode } }`;
  while (true) {
    const resp = await axios.post(
      `https://${shop}/admin/api/${API_VERSION}/graphql.json`,
      { query },
      { headers: { 'X-Shopify-Access-Token': accessToken } }
    );
    const op = resp.data.data.currentBulkOperation;
    logStep('4.2', `Bulk operation status: ${op.status}`);
    if (op.status === 'COMPLETED') {
      logStep('4.2', `✅ Export URL ready`);
      return op.url;
    }
    if (op.status === 'FAILED') throw new Error(`Bulk export failed: ${op.errorCode}`);
    await new Promise(r => setTimeout(r, 5000));
  }
}

async function downloadToFile(fileUrl) {
  ensureDir(exportDir);
  const fname = path.join(exportDir, `${timestamp()}_bulk_export.ndjson`);

  if (!fileUrl) {
    await fs.promises.writeFile(fname, '', 'utf8');
    logStep('4.3', `⚠️ No file URL — created empty export file`);
    return fname;
  }

  const fileStream = fs.createWriteStream(fname);
  await new Promise((resolve, reject) => {
    https.get(fileUrl, res => {
      res.pipe(fileStream);
      fileStream.on('finish', () => fileStream.close(resolve));
      fileStream.on('error', reject);
    });
  });
  logStep('4.3', `✅ Downloaded export to ${fname}`);
  return fname;
}

async function buildHandleMap(ndjsonPath, desiredInventoryByHandle) {
  logStep('5', 'Building handle → inventory map...');
  const handleMap = {};
  const productIdToHandle = {};

  const rl = readline.createInterface({
    input: fs.createReadStream(ndjsonPath),
    crlfDelay: Infinity,
  });

  for await (const line of rl) {
    const rec = JSON.parse(line);
    if (rec.handle && rec.id) productIdToHandle[rec.id] = rec.handle;
    if (rec.__parentId && rec.inventoryItem?.id) {
      const handle = productIdToHandle[rec.__parentId];
      if (handle && desiredInventoryByHandle[handle] != null) {
        if (!handleMap[handle]) handleMap[handle] = [];
        handleMap[handle].push({ inventoryItemId: rec.inventoryItem.id });
      }
    }
  }

  logStep('5', `✅ Mapped ${Object.keys(handleMap).length} handles`);
  return handleMap;
}

function writeBulkInventoryJSONL(handleMap, desiredInventoryByHandle, outputPath, locationId) {
  logStep('6', 'Writing JSONL inventory updates...');
  const stream = fs.createWriteStream(outputPath);
  const updates = [];

  for (const [handle, items] of Object.entries(handleMap)) {
    const qty = desiredInventoryByHandle[handle];
    if (qty == null) continue;
    items.forEach(({ inventoryItemId }) => {
      const entry = { inventoryItemId, quantity: qty, locationId };
      updates.push(entry);
      stream.write(JSON.stringify({ input: entry }) + '\n');
    });
  }

  stream.end();
  logStep('6', `✅ Wrote ${updates.length} inventory adjustments`);
  return updates;
}

async function updateInventoryBatch(batch, index, shop, accessToken) {
  logStep(`7.${index}`, `Updating inventory batch of ${batch.length} items...`);
  const mutation = `
    mutation {
      inventorySetQuantities(input: {
        name: "available",
        reason: "correction",
        ignoreCompareQuantity: true,
        quantities: [
          ${batch.map(item => `{
            inventoryItemId: "${item.inventoryItemId}",
            locationId: "${item.locationId}",
            quantity: ${item.quantity}
          }`).join(',\n')}
        ]
      }) {
        inventoryAdjustmentGroup { id }
        userErrors { field message }
      }
    }
  `;

  try {
    const res = await axios.post(
      `https://${shop}/admin/api/2025-07/graphql.json`,
      { query: mutation },
      {
        headers: {
          'Content-Type': 'application/json',
          'X-Shopify-Access-Token': accessToken,
        },
      }
    );

    const json = res.data;
    const userErrors = json.data?.inventorySetQuantities?.userErrors;
    if (json.errors || userErrors?.length) {
      console.error(`[7.${index}] ❌ Errors:`, JSON.stringify(json.errors || userErrors));
    } else {
      logStep(`7.${index}`, '✅ Batch updated successfully');
    }
  } catch (err) {
    console.error(`[7.${index}] ❌ Axios error:`, err.response?.data || err.message);
  }
}

// ─── MASTER FUNCTION ──────────────────────────────────────────────

async function syncTurn14Inventory(shop, accessToken, FULFILLMENTSERVICEID, LOCATIONID) {
  logStep('0', `🔧 Starting syncTurn14Inventory for ${shop}...`);

  // Step 1: Get Turn14 token — skip shop if credentials are missing
  let turn14Token;
  try {
    turn14Token = await getTurn14AccessToken(shop, accessToken);
  } catch (err) {
    logStep('1', `⚠️ Skipping ${shop} — could not get Turn14 token: ${err.message}`);
    return;
  }

  if (!turn14Token) {
    logStep('1', `⚠️ Skipping ${shop} — Turn14 token is empty.`);
    return;
  }

  try {
    const desiredInventoryByHandle = {};

    // Step 1: Fetch Turn14 inventory
    logStep('1', 'Fetching Turn14 inventory...');
    const turn14Res = await fetch('https://turn14.data4autos.com/v1/inventory/allupdates', {
      headers: {
        Authorization: `Bearer ${turn14Token}`,
        'Content-Type': 'application/json',
      },
    });

    logStep('1', `Turn14 API response status: ${turn14Res.status}`);

    if (!turn14Res.ok) {
      const body = await turn14Res.text();
      throw new Error(`Turn14 inventory fetch failed (${turn14Res.status}): ${body.slice(0, 200)}`);
    }

    const turn14Data = await turn14Res.json();
    turn14Data.forEach(item => {
      desiredInventoryByHandle[item.id] = item.totalQuantity;
    });
    logStep('1', `✅ Loaded ${Object.keys(desiredInventoryByHandle).length} items from Turn14`);

    // Step 2: Ensure export dir exists
    ensureDir(exportDir);

    // Step 3: Get location ID
    const locationId = LOCATIONID || await getLocationID(shop, accessToken);
    logStep('2', `✅ Using location ID: ${locationId}`);

    // Steps 4-6: Shopify bulk export, mapping, JSONL
    await startBulkExport(shop, accessToken);
    const url = await pollUntilReady(shop, accessToken);
    const ndjsonPath = await downloadToFile(url);
    const handleMap = await buildHandleMap(ndjsonPath, desiredInventoryByHandle);
    const jsonlPath = path.join(exportDir, JSONL_FILENAME);
    const inventoryUpdates = writeBulkInventoryJSONL(handleMap, desiredInventoryByHandle, jsonlPath, locationId);

    // Step 7: Update in batches
    const batches = chunkArray(inventoryUpdates, BATCH_SIZE);
    for (let i = 0; i < batches.length; i++) {
      await updateInventoryBatch(batches[i], i + 1, shop, accessToken);
    }

    logStep('8', `✅ Inventory sync complete for ${shop}`);
  } catch (err) {
    logStep('🚨 ERROR', `Sync failed for ${shop}: ${err.message}`);
    // Do NOT process.exit — let the next shop continue and PM2 stay alive
  }
}

export { syncTurn14Inventory };