use serde::Serialize;
use ssh2::Session;
use std::net::{ SocketAddr, TcpStream };
use std::process::Command;
use std::time::Duration;

#[derive(Serialize)]
pub struct OpenWrtDetectionResult {
    detected: bool,
    ip: Option<String>,
    method: String,
    ssh_reachable: bool,
    message: String,
}

#[derive(Serialize)]
pub struct OpenWrtCompatibility {
    compatible: bool,
    version: Option<String>,
    target: Option<String>,
    arch: Option<String>,
    reason: Option<String>,
}

#[derive(Serialize)]
pub struct OpenWrtSshResult {
    connected: bool,
    host: String,
    hostname: Option<String>,
    openwrt_release: Option<String>,
    compatibility: Option<OpenWrtCompatibility>,
    readiness: Option<OpenWrtReadiness>,
    message: String,
}

#[derive(Serialize)]
pub struct OpenWrtReadiness {
    internet_ok: bool,
    dns_ok: bool,
    opkg_ok: bool,
    openvpn_installed: bool,
    free_space: Option<String>,
    free_memory: Option<String>,
}

#[derive(Serialize)]
pub struct OpenWrtPrepareResult {
    success: bool,
    hostname_updated: bool,
    password_updated: bool,
    message: String,
    logs: String,
}

#[tauri::command]
pub fn detect_openwrt_router() -> OpenWrtDetectionResult {
    let candidates = vec![detect_default_gateway(), Some("192.168.1.1".to_string())];

    for candidate in candidates.into_iter().flatten() {
        if tcp_port_open(&candidate, 22) {
            return OpenWrtDetectionResult {
                detected: true,
                ip: Some(candidate),
                method: "SSH_PORT_22".to_string(),
                ssh_reachable: true,
                message: "Router detectado com SSH disponível.".to_string(),
            };
        }
    }

    OpenWrtDetectionResult {
        detected: false,
        ip: None,
        method: "NONE".to_string(),
        ssh_reachable: false,
        message: "Nenhum router OpenWRT detetado automaticamente.".to_string(),
    }
}

#[tauri::command]
pub fn test_openwrt_ssh(host: String, username: String, password: String) -> OpenWrtSshResult {
    let address = format!("{}:22", host);

    let socket = match address.parse::<SocketAddr>() {
        Ok(socket) => socket,
        Err(err) => {
            return OpenWrtSshResult {
                connected: false,
                host,
                hostname: None,
                openwrt_release: None,
                compatibility: None,
                readiness: None,
                message: format!("Endereço inválido: {}", err),
            };
        }
    };

    let tcp = match TcpStream::connect_timeout(&socket, Duration::from_secs(5)) {
        Ok(stream) => stream,
        Err(err) => {
            return OpenWrtSshResult {
                connected: false,
                host,
                hostname: None,
                openwrt_release: None,
                compatibility: None,
                readiness: None,
                message: format!("Falha ao ligar por TCP/SSH: {}", err),
            };
        }
    };

    let mut session = match Session::new() {
        Ok(session) => session,
        Err(err) => {
            return OpenWrtSshResult {
                connected: false,
                host,
                hostname: None,
                openwrt_release: None,
                compatibility: None,
                readiness: None,
                message: format!("Falha ao criar sessão SSH: {}", err),
            };
        }
    };

    session.set_tcp_stream(tcp);

    if let Err(err) = session.handshake() {
        return OpenWrtSshResult {
            connected: false,
            host,
            hostname: None,
            openwrt_release: None,
            compatibility: None,
            readiness: None,
            message: format!("Falha no handshake SSH: {}", err),
        };
    }

    if password.trim().is_empty() {
        return test_openwrt_ssh_with_system_ssh(host, username);
    }

    if let Err(err) = session.userauth_password(&username, &password) {
        return OpenWrtSshResult {
            connected: false,
            host,
            hostname: None,
            openwrt_release: None,
            compatibility: None,
            readiness: None,
            message: format!("Falha na autenticação SSH: {}", err),
        };
    }

    let hostname = run_ssh_command(
        &session,
        "uci get system.@system[0].hostname 2>/dev/null || hostname"
    );

    let release = run_ssh_command(&session, "cat /etc/openwrt_release 2>/dev/null");

    let compatibility = release.as_ref().map(|content| build_compatibility(content));

    let readiness = Some(build_readiness(&session));

    OpenWrtSshResult {
        connected: true,
        host,
        hostname,
        openwrt_release: release,
        compatibility,
        readiness,
        message: "Ligação SSH estabelecida com sucesso.".to_string(),
    }
}

#[tauri::command]
pub fn prepare_openwrt_router(
    host: String,
    username: String,
    password: String,
    target_hostname: String,
    new_password: String
) -> OpenWrtPrepareResult {
    if target_hostname.trim().is_empty() {
        return OpenWrtPrepareResult {
            success: false,
            hostname_updated: false,
            password_updated: false,
            message: "Hostname inválido.".to_string(),
            logs: "".to_string(),
        };
    }

    if new_password.trim().is_empty() {
        return OpenWrtPrepareResult {
            success: false,
            hostname_updated: false,
            password_updated: false,
            message: "Password root inválida.".to_string(),
            logs: "".to_string(),
        };
    }

    if password.trim().is_empty() {
        return prepare_openwrt_router_with_system_ssh(
            host,
            username,
            target_hostname,
            new_password
        );
    }

    let address = format!("{}:22", host);

    let socket = match address.parse::<SocketAddr>() {
        Ok(socket) => socket,
        Err(err) => {
            return OpenWrtPrepareResult {
                success: false,
                hostname_updated: false,
                password_updated: false,
                message: format!("Endereço inválido: {}", err),
                logs: "".to_string(),
            };
        }
    };

    let tcp = match TcpStream::connect_timeout(&socket, Duration::from_secs(5)) {
        Ok(stream) => stream,
        Err(err) => {
            return OpenWrtPrepareResult {
                success: false,
                hostname_updated: false,
                password_updated: false,
                message: format!("Falha ao ligar por TCP/SSH: {}", err),
                logs: "".to_string(),
            };
        }
    };

    let mut session = match Session::new() {
        Ok(session) => session,
        Err(err) => {
            return OpenWrtPrepareResult {
                success: false,
                hostname_updated: false,
                password_updated: false,
                message: format!("Falha ao criar sessão SSH: {}", err),
                logs: "".to_string(),
            };
        }
    };

    session.set_tcp_stream(tcp);

    if let Err(err) = session.handshake() {
        return OpenWrtPrepareResult {
            success: false,
            hostname_updated: false,
            password_updated: false,
            message: format!("Falha no handshake SSH: {}", err),
            logs: "".to_string(),
        };
    }

    if let Err(err) = session.userauth_password(&username, &password) {
        return OpenWrtPrepareResult {
            success: false,
            hostname_updated: false,
            password_updated: false,
            message: format!("Falha na autenticação SSH: {}", err),
            logs: "".to_string(),
        };
    }

    let command = build_prepare_command(&target_hostname, &new_password);

    let logs = run_ssh_command(&session, &command).unwrap_or_default();

    let hostname_updated = logs.contains("HOSTNAME_UPDATED");
    let password_updated = logs.contains("PASSWORD_UPDATED");
    let success = hostname_updated && password_updated;

    OpenWrtPrepareResult {
        success,
        hostname_updated,
        password_updated,
        message: if success {
            "Router preparado com sucesso.".to_string()
        } else {
            "Preparação do router incompleta. Verifique os logs.".to_string()
        },
        logs,
    }
}

fn tcp_port_open(host: &str, port: u16) -> bool {
    let address = format!("{}:{}", host, port);

    match address.parse::<SocketAddr>() {
        Ok(socket) => TcpStream::connect_timeout(&socket, Duration::from_secs(2)).is_ok(),
        Err(_) => false,
    }
}

fn run_ssh_command(session: &Session, command: &str) -> Option<String> {
    let mut channel = session.channel_session().ok()?;
    channel.exec(command).ok()?;

    let mut output = String::new();
    std::io::Read::read_to_string(&mut channel, &mut output).ok()?;

    channel.wait_close().ok()?;

    let trimmed = output.trim().to_string();

    if trimmed.is_empty() {
        None
    } else {
        Some(trimmed)
    }
}

fn detect_default_gateway() -> Option<String> {
    #[cfg(target_os = "windows")]
    {
        let output = Command::new("cmd").args(["/C", "ipconfig"]).output().ok()?;

        let text = String::from_utf8_lossy(&output.stdout);

        for line in text.lines() {
            if line.contains("Default Gateway") {
                if let Some(ip) = line.split(':').nth(1) {
                    let ip = ip.trim();

                    if !ip.is_empty() && ip.contains('.') {
                        return Some(ip.to_string());
                    }
                }
            }
        }
    }

    None
}

fn test_openwrt_ssh_with_system_ssh(host: String, username: String) -> OpenWrtSshResult {
    let target = format!("{}@{}", username, host);

    let output = Command::new("ssh")
        .args([
            "-o",
            "StrictHostKeyChecking=no",
            "-o",
            "UserKnownHostsFile=NUL",
            "-o",
            "BatchMode=yes",
            "-o",
            "ConnectTimeout=5",
            &target,
            "uci get system.@system[0].hostname 2>/dev/null || hostname; \
            echo '---OPENWRT_RELEASE---'; \
            cat /etc/openwrt_release 2>/dev/null; \
            echo '---READINESS---'; \
            ping -c 1 -W 2 1.1.1.1 >/dev/null 2>&1 && echo INTERNET_OK || echo INTERNET_FAIL; \
            nslookup openwrt.org >/dev/null 2>&1 && echo DNS_OK || echo DNS_FAIL; \
            command -v opkg >/dev/null 2>&1 && echo OPKG_OK || echo OPKG_FAIL; \
            command -v openvpn >/dev/null 2>&1 && echo OPENVPN_OK || echo OPENVPN_FAIL; \
            echo FREE_SPACE=$(df -h /overlay 2>/dev/null | awk 'NR==2 {print $4}'); \
            echo FREE_MEMORY=$(free -h 2>/dev/null | awk '/Mem:/ {print $4}')",
        ])
        .output();

    let output = match output {
        Ok(output) => output,
        Err(err) => {
            return OpenWrtSshResult {
                connected: false,
                host,
                hostname: None,
                openwrt_release: None,
                compatibility: None,
                readiness: None,
                message: format!("Falha ao executar ssh local: {}", err),
            };
        }
    };

    if !output.status.success() {
        return OpenWrtSshResult {
            connected: false,
            host,
            hostname: None,
            openwrt_release: None,
            compatibility: None,
            readiness: None,
            message: String::from_utf8_lossy(&output.stderr).trim().to_string(),
        };
    }

    let stdout = String::from_utf8_lossy(&output.stdout).to_string();
    let parts: Vec<&str> = stdout.split("---OPENWRT_RELEASE---").collect();

    let hostname = parts
        .get(0)
        .map(|value| value.trim().to_string())
        .filter(|value| !value.is_empty());

    let release_and_readiness = parts.get(1).copied().unwrap_or("");

    let release_parts: Vec<&str> = release_and_readiness.split("---READINESS---").collect();

    let openwrt_release = release_parts
        .get(0)
        .map(|value| value.trim().to_string())
        .filter(|value| !value.is_empty());

    let readiness_output = release_parts
        .get(1)
        .map(|value| value.trim().to_string())
        .unwrap_or_default();

    let compatibility = openwrt_release.as_ref().map(|content| build_compatibility(content));

    let readiness = Some(build_readiness_from_output(&readiness_output));
    OpenWrtSshResult {
        connected: true,
        host,
        hostname,
        openwrt_release,
        compatibility,
        readiness,
        message: "Ligação SSH estabelecida com sucesso.".to_string(),
    }
}

fn build_compatibility(release_content: &str) -> OpenWrtCompatibility {
    let version = extract_release_value(release_content, "DISTRIB_RELEASE");
    let target = extract_release_value(release_content, "DISTRIB_TARGET");
    let arch = extract_release_value(release_content, "DISTRIB_ARCH");

    let compatible = version
        .as_ref()
        .map(|value| is_supported_openwrt_version(value))
        .unwrap_or(false);

    let reason = if compatible {
        None
    } else {
        Some("Versão OpenWRT não suportada. É necessária a versão 21.02.2 ou superior.".to_string())
    };

    OpenWrtCompatibility {
        compatible,
        version,
        target,
        arch,
        reason,
    }
}

fn extract_release_value(content: &str, key: &str) -> Option<String> {
    content
        .lines()
        .find(|line| line.starts_with(key))
        .and_then(|line| line.split('=').nth(1))
        .map(|value| value.trim().trim_matches('\'').to_string())
        .filter(|value| !value.is_empty())
}

fn is_supported_openwrt_version(version: &str) -> bool {
    let parts: Vec<u32> = version
        .split('.')
        .filter_map(|part| part.parse::<u32>().ok())
        .collect();

    if parts.len() < 2 {
        return false;
    }

    let major = parts[0];
    let minor = parts[1];
    let patch = parts.get(2).copied().unwrap_or(0);

    if major > 21 {
        return true;
    }

    if major == 21 && minor > 2 {
        return true;
    }

    if major == 21 && minor == 2 && patch >= 2 {
        return true;
    }

    false
}

fn build_readiness(session: &Session) -> OpenWrtReadiness {
    let internet_ok = run_ssh_command(
        session,
        "ping -c 1 -W 2 1.1.1.1 >/dev/null 2>&1 && echo OK || echo FAIL"
    )
        .map(|value| value == "OK")
        .unwrap_or(false);

    let dns_ok = run_ssh_command(
        session,
        "nslookup openwrt.org >/dev/null 2>&1 && echo OK || echo FAIL"
    )
        .map(|value| value == "OK")
        .unwrap_or(false);

    let opkg_ok = run_ssh_command(
        session,
        "command -v opkg >/dev/null 2>&1 && echo OK || echo FAIL"
    )
        .map(|value| value == "OK")
        .unwrap_or(false);

    let openvpn_installed = run_ssh_command(
        session,
        "command -v openvpn >/dev/null 2>&1 && echo OK || echo FAIL"
    )
        .map(|value| value == "OK")
        .unwrap_or(false);

    let free_space = run_ssh_command(
        session,
        "df -h /overlay 2>/dev/null | awk 'NR==2 {print $4}'"
    );

    let free_memory = run_ssh_command(session, "free -h 2>/dev/null | awk '/Mem:/ {print $4}'");

    OpenWrtReadiness {
        internet_ok,
        dns_ok,
        opkg_ok,
        openvpn_installed,
        free_space,
        free_memory,
    }
}

fn build_readiness_from_output(output: &str) -> OpenWrtReadiness {
    OpenWrtReadiness {
        internet_ok: output.contains("INTERNET_OK"),
        dns_ok: output.contains("DNS_OK"),
        opkg_ok: output.contains("OPKG_OK"),
        openvpn_installed: output.contains("OPENVPN_OK"),
        free_space: extract_prefixed_value(output, "FREE_SPACE="),
        free_memory: extract_prefixed_value(output, "FREE_MEMORY="),
    }
}

fn extract_prefixed_value(content: &str, prefix: &str) -> Option<String> {
    content
        .lines()
        .find(|line| line.starts_with(prefix))
        .map(|line| line.trim_start_matches(prefix).trim().to_string())
        .filter(|value| !value.is_empty())
}

fn prepare_openwrt_router_with_system_ssh(
    host: String,
    username: String,
    target_hostname: String,
    new_password: String
) -> OpenWrtPrepareResult {
    let target = format!("{}@{}", username, host);
    let command = build_prepare_command(&target_hostname, &new_password);

    let output = Command::new("ssh")
        .args([
            "-o",
            "StrictHostKeyChecking=no",
            "-o",
            "UserKnownHostsFile=NUL",
            "-o",
            "BatchMode=yes",
            "-o",
            "ConnectTimeout=5",
            &target,
            &command,
        ])
        .output();

    let output = match output {
        Ok(output) => output,
        Err(err) => {
            return OpenWrtPrepareResult {
                success: false,
                hostname_updated: false,
                password_updated: false,
                message: format!("Falha ao executar ssh local: {}", err),
                logs: "".to_string(),
            };
        }
    };

    let stdout = String::from_utf8_lossy(&output.stdout).to_string();
    let stderr = String::from_utf8_lossy(&output.stderr).to_string();
    let logs = format!("{}\n{}", stdout, stderr);

    let hostname_updated = logs.contains("HOSTNAME_UPDATED");
    let password_updated = logs.contains("PASSWORD_UPDATED");
    let success = output.status.success() && hostname_updated && password_updated;

    OpenWrtPrepareResult {
        success,
        hostname_updated,
        password_updated,
        message: if success {
            "Router preparado com sucesso.".to_string()
        } else {
            "Preparação do router incompleta. Verifique os logs.".to_string()
        },
        logs,
    }
}

fn build_prepare_command(target_hostname: &str, new_password: &str) -> String {
    let safe_hostname = shell_escape_single_quotes(target_hostname);
    let safe_password = shell_escape_single_quotes(new_password);

    format!(
        "set -e; \
         uci set system.@system[0].hostname='{hostname}'; \
         uci commit system; \
         /etc/init.d/system reload >/dev/null 2>&1 || true; \
         echo HOSTNAME_UPDATED; \
         printf '%s\\n%s\\n' '{password}' '{password}' | passwd root; \
         echo PASSWORD_UPDATED",
        hostname = safe_hostname,
        password = safe_password
    )
}

fn shell_escape_single_quotes(value: &str) -> String {
    value.replace('\'', "'\\''")
}