// models.rs — Shared data models (server + client)
//
// This module defines the structs that represent the IPAM domain entities.
// They are compiled for both the server and WASM, because Leptos needs them
// on both sides:
//   - Server : to read/write the database and render HTML
//   - Client : to display data inside Leptos components
//
// Each struct derives `Serialize` and `Deserialize` from serde.
// This is required for Leptos to transfer data between the server and the
// browser through server functions (#[server]).

use serde::{Deserialize, Serialize};

// ─── Network ──────────────────────────────────────────────────────────────────

/// An IP network defined by its CIDR range.
///
/// Example: { id: 1, cidr: "192.168.1.0/24" }
///   → covers 192.168.1.0 to 192.168.1.255 (254 usable hosts)
///
/// CIDR (Classless Inter-Domain Routing) combines the network address and
/// the subnet mask into a single field: <address>/<prefix length>.
/// /24 = 24-bit mask = 255.255.255.0
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Network {
    /// Unique identifier, auto-incremented by the database.
    /// `i64` is a signed 64-bit integer — maps to `BIGINT` in SQL.
    pub id: i64,

    /// Address range in CIDR notation.
    /// Examples: "10.0.0.0/8", "172.16.0.0/12", "192.168.1.0/24"
    pub cidr: String,
}

// ─── Host ─────────────────────────────────────────────────────────────────────

/// A host (server, workstation, network device) belonging to a network.
///
/// Constraint: the IP address must fall within the CIDR range of the network
/// referenced by `network_id`. This is enforced on creation and update.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Host {
    pub id: i64,

    /// Human-readable name. Examples: "web-server-01", "main-router"
    pub name: String,

    /// IPv4 address stored as text. Example: "192.168.1.10"
    /// We use String instead of IpAddr to simplify serialization
    /// and database storage.
    pub ip: String,

    /// Foreign key referencing the network this host belongs to.
    pub network_id: i64,
}

// ─── Port ─────────────────────────────────────────────────────────────────────

/// A network port entry in the global port catalog.
///
/// Ports are defined once here; host_ports and application_ports link them
/// to hosts and applications through separate join tables.
/// Well-known ports (0–1023) have standardized protocol assignments.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Port {
    /// TCP/UDP port number (0–65535).
    /// `u16` is an unsigned 16-bit integer — the exact range for port numbers.
    pub number: u16,

    /// Description of the protocol typically running on this port.
    /// `Option<String>`: absent (None) when the protocol is unknown.
    /// Examples: Some("SSH"), Some("HTTPS"), None
    pub description: Option<String>,
}

// ─── HostPort ─────────────────────────────────────────────────────────────────

/// Join record representing a port open on a specific host.
///
/// Maps to the `host_ports` table (many-to-many between hosts and ports).
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HostPort {
    pub host_id: i64,
    pub port_number: u16,
}

impl Port {
    /// Returns the standard description for common well-known ports.
    /// Used to pre-fill the description field when adding a port.
    ///
    /// `match` is Rust's exhaustive pattern-matching construct (like switch/case,
    /// but the compiler enforces that all cases are handled).
    pub fn known_protocol(number: u16) -> Option<&'static str> {
        // `&'static str`: a reference to a string that lives for the entire
        // program lifetime (string literals are stored in the compiled binary).
        match number {
            21   => Some("FTP"),
            22   => Some("SSH"),
            23   => Some("Telnet"),
            25   => Some("SMTP"),
            53   => Some("DNS"),
            80   => Some("HTTP"),
            110  => Some("POP3"),
            143  => Some("IMAP"),
            443  => Some("HTTPS"),
            3306 => Some("MySQL"),
            5432 => Some("PostgreSQL"),
            6379 => Some("Redis"),
            8080 => Some("HTTP (alternate)"),
            _    => None, // `_` is the wildcard pattern — matches everything else
        }
    }
}

// ─── Application ──────────────────────────────────────────────────────────────

/// An application that uses one or more ports.
///
/// The association between an application and a port is non-strict:
/// the same port can be shared by multiple applications.
/// Example: port 80 might be used by both Nginx and an application proxy.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Application {
    pub id: i64,

    /// Application name. Examples: "Nginx", "PostgreSQL", "Prometheus"
    pub name: String,
}

// ─── ApplicationPort ──────────────────────────────────────────────────────────

/// Join record linking an application to a port (many-to-many relationship).
///
/// A dedicated struct is used instead of Vec<Port> inside Application
/// so it maps directly to the join table in the database.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ApplicationPort {
    pub application_id: i64,
    pub port_number: u16,
}