import fs from 'fs';
import path from 'path';
import { FileEncryptor } from './file_encryptor';
import { MemoryManager } from './memory_manager';
import { JsonManager } from './json_manager';
import { TcpCommunicator } from './tcp_communicator';
import { operationCodes } from '../network/operation_codes';
import { ParsedMessage } from "../network/message_handler";

export class BackupManager {
    private fileEncryptor: FileEncryptor | null = null;
    private memoryManager: MemoryManager;
    private applicationInfo: JsonManager;
    private userConfig: JsonManager;
    private readonly clientPort: number;
    private isBusy: boolean = false;
    private intervalId: NodeJS.Timeout | null = null;
    private stopRequested: boolean = false;

    constructor(userConfigPath: string, applicationInfoPath: string, memoryManagerPath: string, clientPort: number) {
        this.applicationInfo = new JsonManager(applicationInfoPath);
        this.userConfig = new JsonManager(userConfigPath);
        this.memoryManager = new MemoryManager(memoryManagerPath);
        this.clientPort = clientPort;
    }

    async start(): Promise<void> {
        this.intervalId = setInterval(async () => {
            if (!this.isBusy || !this.stopRequested) {
                this.isBusy = true;
                this.log('Start successfully. Backup files to users.');
                await this.initialize();
            }

            if (global.gc) {
                global.gc();
            }
        }, 10000); // 10-second interval for testing
    }

    private async initialize(): Promise<void> {
        this.isBusy = true;
        try {
            const encryptionKeyData = await this.userConfig.readValue('encryption_key');
            if (!encryptionKeyData || !encryptionKeyData.key || !encryptionKeyData.iv) {
                this.log('Encryption key data is missing in user configuration.', 'error');
                return;
            }

            this.fileEncryptor = new FileEncryptor(encryptionKeyData.key, encryptionKeyData.iv);

            const userInfo = await this.userConfig.readValue('user_info');
            if (!userInfo || !userInfo.name) {
                this.log('User information is missing in user configuration.', 'error');
                return;
            }
            const userName = userInfo.name;

            const backupDirectoryData = await this.applicationInfo.readValue('backupDirectory');
            if (!backupDirectoryData || !backupDirectoryData.id || !backupDirectoryData.path) {
                this.log('Backup directory information is missing in application info.', 'error');
                return;
            }

            const activeUsersIp = await this.applicationInfo.readValue('users_ip');
            if (!activeUsersIp || !activeUsersIp.length) {
                this.log('No active users found.', 'error');
                return;
            }

            const backupDirectoryId = backupDirectoryData.id;
            const backupDirectoryPath = backupDirectoryData.path;

            const directoryData = await this.memoryManager.retrieveMetaInformation(backupDirectoryId);
            if (!directoryData || !directoryData.structure) {
                this.log('Backup directory structure is missing in memory.', 'error');
                return;
            }

            await this.sendFilesToUsers(directoryData.structure, userName, activeUsersIp, backupDirectoryPath);
        } catch (error: any) {
            this.log(`Error in initialize process: ${error.message}`, 'error');
        } finally {
            this.log('Backup process completed.');
            this.isBusy = false;
        }
    }

    private encryptFile(filePath: string): string {
        if (!this.fileEncryptor) {
            return filePath;
        }

        if (!fs.existsSync(filePath)) {
            this.log(`File not found: ${filePath}`, 'error');
            return '';
        }

        return this.fileEncryptor.encryptFileToBase64(filePath);
    }

    private async sendFilesToUsers(fileStructure: { [key: string]: string }, userName: string, usersIp: string[], backupDirectoryPath: string): Promise<void> {
        let unsentFiles = Object.keys(fileStructure);

        for (const fileName of unsentFiles) {
            const filePath = fileStructure[fileName];
            const encryptedFileContent = this.encryptFile(filePath);

            if (!encryptedFileContent) {
                this.log(`Failed to encrypt file: ${fileName}`, 'error');
                continue;
            }

            const relativeFilePath = path.relative(backupDirectoryPath, filePath);
            const metaInfo = { userName, relativeFilePath };

            for (const ip of usersIp) {
                const tcpCommunicator = new TcpCommunicator(ip, this.clientPort);

                try {
                    await tcpCommunicator.connect();
                    this.log(`Connected to ${ip}`);

                    const sendSuccess = await tcpCommunicator.sendMessage(operationCodes.BACKUP_FILE, metaInfo, Buffer.from(encryptedFileContent, 'base64'));
                    if (!sendSuccess) {
                        throw new Error('Failed to send file content.');
                    }

                    const responseReceived = await this.waitForResponse(tcpCommunicator);
                    if (!responseReceived) {
                        throw new Error('Timeout waiting for the message response.');
                    }

                    this.log(`Successfully sent file: ${fileName} to ${ip}`);
                    unsentFiles = unsentFiles.filter(f => f !== fileName);
                    break;
                } catch (error) {
                    this.log(`Failed to send file: ${fileName} to ${ip}. Error: ${error}`, 'error');
                } finally {
                    await tcpCommunicator.disconnect();
                    this.log(`Disconnected from ${ip}`);
                }
            }
        }

        if (unsentFiles.length > 0) {
            process.send?.({type: 'log', message: 'Backup could not be completed for all files'});
        } else {
            process.send?.({type: 'log', message: 'Backup completed successfully' });
        }
    }

    private async waitForResponse(tcpCommunicator: TcpCommunicator): Promise<ParsedMessage | null> {
        return new Promise((resolve) => {
            const idResponseCheck = setInterval(() => {
                if (!tcpCommunicator) return null;
                if (tcpCommunicator.hasResponseArrived()) {
                    clearInterval(idResponseCheck);
                    resolve(tcpCommunicator.getLastResult());
                }
            }, 100);
        });
    }

    async stop(): Promise<void> {
        this.stopRequested = true; // Signal that stop is requested

        if (this.intervalId) {
            clearInterval(this.intervalId);
            this.intervalId = null;
        }

        // Wait for any ongoing process to complete if busy
        while (this.isBusy) {
            await new Promise((resolve) => setTimeout(resolve, 100));
        }

        console.log("[BackupManager] Stopped successfully.");
    }

    // Unified logging function
    private log(message: string, level: 'log' | 'error' | 'warn' = 'log'): void {
        const prefix = '[BackupManager]';
        if (level === 'error') {
            console.error(`${prefix} ${message}`);
        } else if (level === 'warn') {
            console.warn(`${prefix} ${message}`);
        } else {
            console.log(`${prefix} ${message}`);
        }
    }
}