import * as fs from "fs";
import * as path from "path";
import config from "@server/lib/config";
import logger from "@server/logger";
import * as yaml from "js-yaml";
import axios from "axios";
import { db, exitNodes } from "@server/db";
import { tokenManager } from "./tokenManager";

export class TraefikConfigManager {
    private intervalId: NodeJS.Timeout | null = null;
    private isRunning = false;
    private activeDomains = new Set<string>();
    private timeoutId: NodeJS.Timeout | null = null;

    constructor() {}

    /**
     * Start monitoring certificates
     */
    private scheduleNextExecution(): void {
        const intervalMs = config.getRawConfig().traefik.monitor_interval;
        const now = Date.now();
        const nextExecution = Math.ceil(now / intervalMs) * intervalMs;
        const delay = nextExecution - now;

        this.timeoutId = setTimeout(async () => {
            try {
                await this.HandleTraefikConfig();
            } catch (error) {
                logger.error("Error during certificate monitoring:", error);
            }

            if (this.isRunning) {
                this.scheduleNextExecution(); // Schedule the next execution
            }
        }, delay);
    }

    async start(): Promise<void> {
        if (this.isRunning) {
            logger.info("Certificate monitor is already running");
            return;
        }
        this.isRunning = true;
        logger.info(`Starting certificate monitor for exit node`);

        // Ensure certificates directory exists
        await this.ensureDirectoryExists(
            config.getRawConfig().traefik.certificates_path
        );

        // Run initial check
        await this.HandleTraefikConfig();

        // Start synchronized scheduling
        this.scheduleNextExecution();

        logger.info(
            `Certificate monitor started with synchronized ${
                config.getRawConfig().traefik.monitor_interval
            }ms interval`
        );
    }
    /**
     * Stop monitoring certificates
     */
    stop(): void {
        if (!this.isRunning) {
            logger.info("Certificate monitor is not running");
            return;
        }

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

        this.isRunning = false;
        logger.info("Certificate monitor stopped");
    }

    /**
     * Main monitoring logic
     */
    lastActiveDomains: Set<string> = new Set();
    public async HandleTraefikConfig(): Promise<void> {
        try {
            // Get all active domains for this exit node via HTTP call
            const getActiveDomainsFromTraefik =
                await this.getActiveDomainsFromTraefik();

            if (!getActiveDomainsFromTraefik) {
                logger.error(
                    "Failed to fetch active domains from traefik config"
                );
                return;
            }

            const { domains, traefikConfig } = getActiveDomainsFromTraefik;

            // Add static domains from config
            // const staticDomains = [config.getRawConfig().app.dashboard_url];
            // staticDomains.forEach((domain) => domains.add(domain));

            // Log if domains changed
            if (
                this.lastActiveDomains.size !== domains.size ||
                !Array.from(this.lastActiveDomains).every((domain) =>
                    domains.has(domain)
                )
            ) {
                logger.info(
                    `Active domains changed for exit node: ${Array.from(domains).join(", ")}`
                );
                this.lastActiveDomains = new Set(domains);
            }

            // Get valid certificates for active domains
            const validCertificates =
                await this.getValidCertificatesForDomains(domains);

            // Download and decrypt new certificates
            await this.processValidCertificates(validCertificates);

            // Clean up certificates for domains no longer in use
            await this.cleanupUnusedCertificates(domains);

            // wait 1 second for traefik to pick up the new certificates
            await new Promise((resolve) => setTimeout(resolve, 500));

            // Write traefik config as YAML to a second dynamic config file if changed
            await this.writeTraefikDynamicConfig(traefikConfig);

            // Send domains to SNI proxy
            try {
                const [exitNode] = await db.select().from(exitNodes).limit(1);
                if (exitNode) {
                    logger.error("No exit node found");
                    await axios.post(
                        `${exitNode.reachableAt}/update-local-snis`,
                        { fullDomains: Array.from(domains) },
                        { headers: { "Content-Type": "application/json" } }
                    );
                }
            } catch (err) {
                logger.error("Failed to post domains to SNI proxy:", err);
            }

            // Update active domains tracking
            this.activeDomains = domains;
        } catch (error) {
            logger.error("Error in certificate monitoring cycle:", error);
        }
    }

    /**
     * Get all domains currently in use from traefik config API
     */
    private async getActiveDomainsFromTraefik(): Promise<{
        domains: Set<string>;
        traefikConfig: any;
    } | null> {
        try {
            const resp = await axios.get(
                `${config.getRawConfig().hybrid?.endpoint}/traefik-config`,
                await tokenManager.getAuthHeader()
            );

            if (resp.status !== 200) {
                logger.error(
                    `Failed to fetch traefik config: ${resp.status} ${resp.statusText}`
                );
                return null;
            }

            const traefikConfig = resp.data;
            const domains = new Set<string>();

            if (traefikConfig?.http?.routers) {
                for (const router of Object.values<any>(
                    traefikConfig.http.routers
                )) {
                    if (router.rule && typeof router.rule === "string") {
                        // Match Host(`domain`)
                        const match = router.rule.match(/Host\(`([^`]+)`\)/);
                        if (match && match[1]) {
                            domains.add(match[1]);
                        }
                    }
                }
            }
            return { domains, traefikConfig };
        } catch (err) {
            logger.error("Failed to fetch traefik config:", err);
            return null;
        }
    }

    /**
     * Write traefik config as YAML to a second dynamic config file if changed
     */
    private async writeTraefikDynamicConfig(traefikConfig: any): Promise<void> {
        const traefikDynamicConfigPath =
            config.getRawConfig().traefik.dynamic_router_config_path;
        let shouldWrite = false;
        let oldJson = "";
        if (fs.existsSync(traefikDynamicConfigPath)) {
            try {
                const oldContent = fs.readFileSync(
                    traefikDynamicConfigPath,
                    "utf8"
                );
                // Try to parse as YAML then JSON.stringify for comparison
                const oldObj = yaml.load(oldContent);
                oldJson = JSON.stringify(oldObj);
            } catch {
                oldJson = "";
            }
        }
        const newJson = JSON.stringify(traefikConfig);
        if (oldJson !== newJson) {
            shouldWrite = true;
        }
        if (shouldWrite) {
            try {
                fs.writeFileSync(
                    traefikDynamicConfigPath,
                    yaml.dump(traefikConfig, { noRefs: true }),
                    "utf8"
                );
                logger.info("Traefik dynamic config updated");
            } catch (err) {
                logger.error("Failed to write traefik dynamic config:", err);
            }
        }
    }

    /**
     * Get valid certificates for the specified domains
     */
    private async getValidCertificatesForDomains(domains: Set<string>): Promise<
        Array<{
            id: number;
            domain: string;
            certFile: string | null;
            keyFile: string | null;
            expiresAt: Date | null;
            updatedAt?: Date | null;
        }>
    > {
        if (domains.size === 0) {
            return [];
        }

        const domainArray = Array.from(domains);

        try {
            const response = await axios.get(
                `${config.getRawConfig().hybrid?.endpoint}/certificates/domains`,
                {
                    params: {
                        domains: domainArray
                    },
                    headers: (await tokenManager.getAuthHeader()).headers
                }
            );
            return response.data;
        } catch (error) {
            console.error("Error fetching resource by domain:", error);
            return [];
        }
    }

    /**
     * Process valid certificates - download and decrypt them
     */
    private async processValidCertificates(
        validCertificates: Array<{
            id: number;
            domain: string;
            certFile: string | null;
            keyFile: string | null;
            expiresAt: Date | null;
            updatedAt?: Date | null;
        }>
    ): Promise<void> {
        const dynamicConfigPath =
            config.getRawConfig().traefik.dynamic_cert_config_path;

        // Load existing dynamic config if it exists, otherwise initialize
        let dynamicConfig: any = { tls: { certificates: [] } };
        if (fs.existsSync(dynamicConfigPath)) {
            try {
                const fileContent = fs.readFileSync(dynamicConfigPath, "utf8");
                dynamicConfig = yaml.load(fileContent) || dynamicConfig;
                if (!dynamicConfig.tls)
                    dynamicConfig.tls = { certificates: [] };
                if (!Array.isArray(dynamicConfig.tls.certificates)) {
                    dynamicConfig.tls.certificates = [];
                }
            } catch (err) {
                logger.error("Failed to load existing dynamic config:", err);
            }
        }

        // Keep a copy of the original config for comparison
        const originalConfigYaml = yaml.dump(dynamicConfig, { noRefs: true });

        for (const cert of validCertificates) {
            try {
                if (!cert.certFile || !cert.keyFile) {
                    logger.warn(
                        `Certificate for domain ${cert.domain} is missing cert or key file`
                    );
                    continue;
                }

                const domainDir = path.join(
                    config.getRawConfig().traefik.certificates_path,
                    cert.domain
                );
                await this.ensureDirectoryExists(domainDir);

                const certPath = path.join(domainDir, "cert.pem");
                const keyPath = path.join(domainDir, "key.pem");
                const lastUpdatePath = path.join(domainDir, ".last_update");

                // Check if we need to update the certificate
                const shouldUpdate = await this.shouldUpdateCertificate(
                    cert,
                    certPath,
                    keyPath,
                    lastUpdatePath
                );

                if (shouldUpdate) {
                    logger.info(
                        `Processing certificate for domain: ${cert.domain}`
                    );

                    fs.writeFileSync(certPath, cert.certFile, "utf8");
                    fs.writeFileSync(keyPath, cert.keyFile, "utf8");

                    // Set appropriate permissions (readable by owner only for key file)
                    fs.chmodSync(certPath, 0o644);
                    fs.chmodSync(keyPath, 0o600);

                    // Write/update .last_update file with current timestamp
                    fs.writeFileSync(
                        lastUpdatePath,
                        new Date().toISOString(),
                        "utf8"
                    );

                    logger.info(
                        `Certificate updated for domain: ${cert.domain}`
                    );
                }

                // Always ensure the config entry exists and is up to date
                const certEntry = {
                    certFile: `/var/${certPath}`,
                    keyFile: `/var/${keyPath}`
                };
                // Remove any existing entry for this cert/key path
                dynamicConfig.tls.certificates =
                    dynamicConfig.tls.certificates.filter(
                        (entry: any) =>
                            entry.certFile !== certEntry.certFile ||
                            entry.keyFile !== certEntry.keyFile
                    );
                dynamicConfig.tls.certificates.push(certEntry);
            } catch (error) {
                logger.error(
                    `Error processing certificate for domain ${cert.domain}:`,
                    error
                );
            }
        }

        // Only write the config if it has changed
        const newConfigYaml = yaml.dump(dynamicConfig, { noRefs: true });
        if (newConfigYaml !== originalConfigYaml) {
            fs.writeFileSync(dynamicConfigPath, newConfigYaml, "utf8");
            logger.info("Dynamic cert config updated");
        }
    }

    /**
     * Check if certificate should be updated
     */
    private async shouldUpdateCertificate(
        cert: {
            id: number;
            domain: string;
            expiresAt: Date | null;
            updatedAt?: Date | null;
        },
        certPath: string,
        keyPath: string,
        lastUpdatePath: string
    ): Promise<boolean> {
        try {
            // If files don't exist, we need to create them
            const certExists = await this.fileExists(certPath);
            const keyExists = await this.fileExists(keyPath);
            const lastUpdateExists = await this.fileExists(lastUpdatePath);

            if (!certExists || !keyExists || !lastUpdateExists) {
                return true;
            }

            // Read last update time from .last_update file
            let lastUpdateTime: Date | null = null;
            try {
                const lastUpdateStr = fs
                    .readFileSync(lastUpdatePath, "utf8")
                    .trim();
                lastUpdateTime = new Date(lastUpdateStr);
            } catch {
                lastUpdateTime = null;
            }

            // Use updatedAt from cert, fallback to expiresAt if not present
            const dbUpdateTime = cert.updatedAt ?? cert.expiresAt;

            if (!dbUpdateTime) {
                // If no update time in DB, always update
                return true;
            }

            // If DB updatedAt is newer than last update file, update
            if (!lastUpdateTime || dbUpdateTime > lastUpdateTime) {
                return true;
            }

            return false;
        } catch (error) {
            logger.error(
                `Error checking certificate update status for ${cert.domain}:`,
                error
            );
            return true; // When in doubt, update
        }
    }

    /**
     * Clean up certificates for domains no longer in use
     */
    private async cleanupUnusedCertificates(
        currentActiveDomains: Set<string>
    ): Promise<void> {
        try {
            const certsPath = config.getRawConfig().traefik.certificates_path;
            const dynamicConfigPath =
                config.getRawConfig().traefik.dynamic_cert_config_path;

            // Load existing dynamic config if it exists
            let dynamicConfig: any = { tls: { certificates: [] } };
            if (fs.existsSync(dynamicConfigPath)) {
                try {
                    const fileContent = fs.readFileSync(
                        dynamicConfigPath,
                        "utf8"
                    );
                    dynamicConfig = yaml.load(fileContent) || dynamicConfig;
                    if (!dynamicConfig.tls)
                        dynamicConfig.tls = { certificates: [] };
                    if (!Array.isArray(dynamicConfig.tls.certificates)) {
                        dynamicConfig.tls.certificates = [];
                    }
                } catch (err) {
                    logger.error(
                        "Failed to load existing dynamic config:",
                        err
                    );
                }
            }

            const certDirs = fs.readdirSync(certsPath, {
                withFileTypes: true
            });

            let configChanged = false;

            for (const dirent of certDirs) {
                if (!dirent.isDirectory()) continue;

                const dirName = dirent.name;
                // Only delete if NO current domain is exactly the same or ends with `.${dirName}`
                const shouldDelete = !Array.from(currentActiveDomains).some(
                    (domain) =>
                        domain === dirName || domain.endsWith(`.${dirName}`)
                );

                if (shouldDelete) {
                    const domainDir = path.join(certsPath, dirName);
                    logger.info(
                        `Cleaning up unused certificate directory: ${dirName}`
                    );
                    fs.rmSync(domainDir, { recursive: true, force: true });

                    // Remove from dynamic config
                    const certFilePath = `/var/${path.join(
                        domainDir,
                        "cert.pem"
                    )}`;
                    const keyFilePath = `/var/${path.join(
                        domainDir,
                        "key.pem"
                    )}`;
                    const before = dynamicConfig.tls.certificates.length;
                    dynamicConfig.tls.certificates =
                        dynamicConfig.tls.certificates.filter(
                            (entry: any) =>
                                entry.certFile !== certFilePath &&
                                entry.keyFile !== keyFilePath
                        );
                    if (dynamicConfig.tls.certificates.length !== before) {
                        configChanged = true;
                    }
                }
            }

            if (configChanged) {
                try {
                    fs.writeFileSync(
                        dynamicConfigPath,
                        yaml.dump(dynamicConfig, { noRefs: true }),
                        "utf8"
                    );
                    logger.info("Dynamic config updated after cleanup");
                } catch (err) {
                    logger.error(
                        "Failed to update dynamic config after cleanup:",
                        err
                    );
                }
            }
        } catch (error) {
            logger.error("Error during certificate cleanup:", error);
        }
    }

    /**
     * Ensure directory exists
     */
    private async ensureDirectoryExists(dirPath: string): Promise<void> {
        try {
            fs.mkdirSync(dirPath, { recursive: true });
        } catch (error) {
            logger.error(`Error creating directory ${dirPath}:`, error);
            throw error;
        }
    }

    /**
     * Check if file exists
     */
    private async fileExists(filePath: string): Promise<boolean> {
        try {
            fs.accessSync(filePath);
            return true;
        } catch {
            return false;
        }
    }

    /**
     * Get current status
     */
    getStatus(): {
        isRunning: boolean;
        activeDomains: string[];
        monitorInterval: number;
    } {
        return {
            isRunning: this.isRunning,
            activeDomains: Array.from(this.activeDomains),
            monitorInterval:
                config.getRawConfig().traefik.monitor_interval || 5000
        };
    }
}