import Imap from "imap";
import { simpleParser, ParsedMail, Attachment } from "mailparser";
import {
  getImportSettingsByUser,
  createSourceFile,
  updateSourceFile,
  getUserSettings,
  findDuplicateInvoice,
  createInvoice,
  createImportLog,
} from "./db";
import { extractInvoicesWithMistral, generateMetadataJSON } from "./invoiceExtractor";
import { localStoragePut, generateStorageKey } from "./localStorage";
import { sendImportNotification } from "./notificationService";

interface EmailImportConfig {
  userId: number;
  emailAddress: string;
  password: string;
  host: string;
  port: number;
}

// Store active intervals for each user
const activeIntervals = new Map<number, NodeJS.Timeout>();

/**
 * Process a single email attachment (PDF)
 * Replicates the same logic as manual upload
 */
async function processEmailAttachment(
  userId: number,
  attachment: Attachment,
  emailSubject: string
): Promise<{ success: boolean; totalInvoices: number; imported: number; duplicates: number; errors: number }> {
  const fileName = attachment.filename || `email-attachment-${Date.now()}.pdf`;
  console.log(`[EmailImport] Processing attachment: ${fileName} from email: ${emailSubject}`);
  
  try {
    // Convert attachment content to Buffer
    const fileBuffer = attachment.content;
    console.log(`[EmailImport] File size: ${fileBuffer.length} bytes`);
    
    // Store source file
    const sourceFileKey = generateStorageKey(userId, fileName);
    console.log(`[EmailImport] Generated storage key: ${sourceFileKey}`);
    
    let sourceFileUrl: string;
    try {
      const result = await localStoragePut(sourceFileKey, fileBuffer, "application/pdf");
      sourceFileUrl = result.url;
      console.log(`[EmailImport] File stored successfully at: ${sourceFileUrl}`);
    } catch (error) {
      console.error(`[EmailImport] FAILED to store file:`, error);
      throw new Error("Failed to store PDF file");
    }
    
    // Create source file record
    const sourceFile = await createSourceFile({
      userId,
      fileName,
      fileKey: sourceFileKey,
      fileUrl: sourceFileUrl,
      processingStatus: "processing",
    });
    
    console.log(`[EmailImport] Source file record created with ID: ${sourceFile.id}`);
    
    // Get user settings for custom keywords
    const settings = await getUserSettings(userId);
    const customKeywords = settings ? {
      invoiceNumber: settings.invoiceNumberKeywords,
      deliveryNote: settings.deliveryNoteKeywords,
      orderNumber: settings.orderNumberKeywords,
      supplier: settings.supplierKeywords,
      totalAmount: settings.totalAmountKeywords,
    } : undefined;
    
    const model = settings?.llmModel || "mistral-large-latest";
    
    // Extract invoices
    console.log(`[EmailImport] Starting invoice extraction...`);
    const result = await extractInvoicesWithMistral(
      fileBuffer,
      userId,
      sourceFile.id,
      model,
      customKeywords
    );
    
    console.log(`[EmailImport] Extraction complete: ${result.invoiceCount} invoice(s) detected`);
    
    // Update source file with total count
    await updateSourceFile(sourceFile.id, {
      totalInvoicesDetected: result.invoiceCount,
      processingProgress: `Extraction ${result.invoiceCount} facture(s) détectée(s)`,
    });
    
    // Process each invoice
    let importedCount = 0;
    let duplicatesCount = 0;
    let errorsCount = 0;
    const duplicateDetails: any[] = [];
    const errorDetails: any[] = [];
    
    for (let i = 0; i < result.invoices.length; i++) {
      const invoiceData = result.invoices[i]!;
      
      try {
        // Update progress
        await updateSourceFile(sourceFile.id, {
          processingProgress: `Extraction ${i + 1}/${result.invoiceCount} factures...`,
        });
        
        // Check for duplicates
        const duplicate = await findDuplicateInvoice(
          invoiceData.supplierName,
          invoiceData.invoiceNumber,
          invoiceData.invoiceDate
        );
        
        if (duplicate) {
          duplicatesCount++;
          duplicateDetails.push({
            supplierName: invoiceData.supplierName,
            invoiceNumber: invoiceData.invoiceNumber,
            invoiceDate: invoiceData.invoiceDate,
          });
          continue;
        }
        
        // Generate metadata JSON
        const metadataJson = generateMetadataJSON(invoiceData);
        const metadataKey = generateStorageKey(userId, `${fileName}-${i + 1}-metadata.json`);
        const { url: metadataUrl } = await localStoragePut(
          metadataKey,
          Buffer.from(metadataJson),
          "application/json"
        );
        
        // Create invoice record
        await createInvoice({
          userId,
          sourceFileId: sourceFile.id,
          invoiceIndexInFile: i + 1,
          fileName: `${fileName} - Facture ${i + 1}`,
          fileKey: sourceFileKey,
          fileUrl: sourceFileUrl,
          supplierName: invoiceData.supplierName,
          invoiceNumber: invoiceData.invoiceNumber,
          invoiceDate: invoiceData.invoiceDate,
          deliveryNoteNumber: invoiceData.deliveryNoteNumber,
          orderNumber: invoiceData.orderNumber,
          totalAmount: invoiceData.totalAmount?.toString(),
          pageRange: invoiceData.pageRange,
          qualityScore: invoiceData.qualityScore,
          metadataFileKey: metadataKey,
          metadataFileUrl: metadataUrl,
          status: "completed",
        });
        
        importedCount++;
      } catch (error: any) {
        errorsCount++;
        errorDetails.push({
          invoiceIndex: i + 1,
          error: error.message,
        });
      }
    }
    
    // Update source file status
    await updateSourceFile(sourceFile.id, {
      processingStatus: "completed",
      processingProgress: `Terminé: ${importedCount} importée(s), ${duplicatesCount} doublon(s)`,
    });
    
    // Create import log
    await createImportLog({
      userId,
      sourceFileId: sourceFile.id,
      fileName,
      totalInvoicesDetected: result.invoiceCount,
      invoicesImported: importedCount,
      duplicatesIgnored: duplicatesCount,
      errors: errorsCount,
      duplicateDetails: duplicateDetails.length > 0 ? JSON.stringify(duplicateDetails) : null,
      errorDetails: errorDetails.length > 0 ? JSON.stringify(errorDetails) : null,
    });
    
    console.log(`[EmailImport] Successfully processed attachment: ${fileName}`);
    console.log(`[EmailImport] Results: ${importedCount} imported, ${duplicatesCount} duplicates, ${errorsCount} errors`);
    
    return {
      success: true,
      totalInvoices: result.invoiceCount,
      imported: importedCount,
      duplicates: duplicatesCount,
      errors: errorsCount,
    };
  } catch (error) {
    console.error(`[EmailImport] Error processing attachment ${attachment.filename}:`, error);
    return {
      success: false,
      totalInvoices: 0,
      imported: 0,
      duplicates: 0,
      errors: 1,
    };
  }
}

/**
 * Connect to IMAP and process unread emails with PDF attachments
 */
async function checkEmailsForPDFs(config: EmailImportConfig): Promise<void> {
  return new Promise((resolve, reject) => {
    const imap = new Imap({
      user: config.emailAddress,
      password: config.password,
      host: config.host,
      port: config.port,
      tls: true,
      tlsOptions: { rejectUnauthorized: false },
    });

    function openInbox(cb: (err: Error | null, box?: any) => void) {
      imap.openBox("INBOX", false, cb);
    }

    imap.once("ready", () => {
      console.log(`[EmailImport] Connected to IMAP server for user ${config.userId}`);
      
      openInbox((err, box) => {
        if (err) {
          console.error("[EmailImport] Error opening inbox:", err);
          imap.end();
          reject(err);
          return;
        }

        // Search for unread emails
        imap.search(["UNSEEN"], (err, results) => {
          if (err) {
            console.error("[EmailImport] Error searching emails:", err);
            imap.end();
            reject(err);
            return;
          }

          if (!results || results.length === 0) {
            console.log(`[EmailImport] No unread emails found for user ${config.userId}`);
            imap.end();
            resolve();
            return;
          }

          console.log(`[EmailImport] Found ${results.length} unread emails for user ${config.userId}`);

          const fetch = imap.fetch(results, {
            bodies: "",
            markSeen: false, // Don't mark as seen yet
          });

          const processedEmails: number[] = [];

          fetch.on("message", (msg, seqno) => {
            msg.on("body", (stream) => {
              simpleParser(stream as any, async (err, parsed: ParsedMail) => {
                if (err) {
                  console.error("[EmailImport] Error parsing email:", err);
                  return;
                }

                // Check if email has PDF attachments
                const pdfAttachments = parsed.attachments.filter(
                  (att) =>
                    att.contentType === "application/pdf" ||
                    att.filename?.toLowerCase().endsWith(".pdf")
                );

                if (pdfAttachments.length === 0) {
                  console.log(`[EmailImport] Email ${seqno} has no PDF attachments, skipping`);
                  return;
                }

                console.log(
                  `[EmailImport] Email ${seqno} has ${pdfAttachments.length} PDF attachment(s)`
                );

                // Process each PDF attachment
                for (const attachment of pdfAttachments) {
                  try {
                    const result = await processEmailAttachment(
                      config.userId,
                      attachment,
                      parsed.subject || "No subject"
                    );
                    
                    // Mark this email as successfully processed
                    if (!processedEmails.includes(seqno)) {
                      processedEmails.push(seqno);
                    }
                    
                    // Send notification after successful processing
                    if (result.success) {
                      await sendImportNotification(config.userId, {
                        source: "email",
                        fileName: attachment.filename || "email-attachment.pdf",
                        totalInvoices: result.totalInvoices,
                        imported: result.imported,
                        duplicates: result.duplicates,
                        errors: result.errors,
                      });
                    }
                  } catch (error) {
                    console.error(
                      `[EmailImport] Failed to process attachment from email ${seqno}:`,
                      error
                    );
                  }
                }
              });
            });
          });

          fetch.once("error", (err) => {
            console.error("[EmailImport] Fetch error:", err);
            imap.end();
            reject(err);
          });

          fetch.once("end", () => {
            console.log(`[EmailImport] Finished fetching emails for user ${config.userId}`);
            
            // Mark successfully processed emails as seen
            if (processedEmails.length > 0) {
              imap.addFlags(processedEmails, ["\\Seen"], (err) => {
                if (err) {
                  console.error("[EmailImport] Error marking emails as seen:", err);
                } else {
                  console.log(`[EmailImport] Marked ${processedEmails.length} emails as seen`);
                }
                imap.end();
                resolve();
              });
            } else {
              imap.end();
              resolve();
            }
          });
        });
      });
    });

    imap.once("error", (err) => {
      console.error("[EmailImport] IMAP connection error:", err);
      reject(err);
    });

    imap.once("end", () => {
      console.log(`[EmailImport] IMAP connection ended for user ${config.userId}`);
    });

    imap.connect();
  });
}

/**
 * Start email import service for a user
 */
export async function startEmailImportService(userId: number): Promise<boolean> {
  try {
    // Get user's import settings
    const settings = await getImportSettingsByUser(userId);
    
    if (!settings || settings.emailImportEnabled !== 1) {
      console.log(`[EmailImport] Email import not enabled for user ${userId}`);
      return false;
    }

    if (!settings.emailImportAddress || !settings.emailImportPassword || !settings.emailImportHost) {
      console.log(`[EmailImport] Email import configuration incomplete for user ${userId}`);
      return false;
    }

    // Stop existing service if running
    stopEmailImportService(userId);

    const config: EmailImportConfig = {
      userId,
      emailAddress: settings.emailImportAddress,
      password: settings.emailImportPassword,
      host: settings.emailImportHost,
      port: settings.emailImportPort || 993,
    };

    const frequencyMs = (settings.emailImportFrequency || 30) * 60 * 1000; // Convert minutes to milliseconds

    console.log(
      `[EmailImport] Starting email import service for user ${userId} with frequency ${settings.emailImportFrequency} minutes`
    );

    // Run immediately on start
    checkEmailsForPDFs(config).catch((error) => {
      console.error(`[EmailImport] Error checking emails for user ${userId}:`, error);
    });

    // Set up interval for periodic checks
    const interval = setInterval(() => {
      checkEmailsForPDFs(config).catch((error) => {
        console.error(`[EmailImport] Error checking emails for user ${userId}:`, error);
      });
    }, frequencyMs);

    activeIntervals.set(userId, interval);
    console.log(`[EmailImport] Email import service started for user ${userId}`);
    
    return true;
  } catch (error) {
    console.error(`[EmailImport] Error starting email import service for user ${userId}:`, error);
    return false;
  }
}

/**
 * Stop email import service for a user
 */
export function stopEmailImportService(userId: number): void {
  const interval = activeIntervals.get(userId);
  if (interval) {
    clearInterval(interval);
    activeIntervals.delete(userId);
    console.log(`[EmailImport] Email import service stopped for user ${userId}`);
  }
}

/**
 * Check if email import service is running for a user
 */
export function isEmailImportServiceRunning(userId: number): boolean {
  return activeIntervals.has(userId);
}

/**
 * Stop all email import services
 */
export function stopAllEmailImportServices(): void {
  activeIntervals.forEach((interval, userId) => {
    clearInterval(interval);
    console.log(`[EmailImport] Stopped email import service for user ${userId}`);
  });
  activeIntervals.clear();
}