//! Saved SSH hosts. Persisted to `%APPDATA%\com.megaproxy.tiletopia\hosts.json`
//! alongside `workspace.json`. The frontend owns the in-memory state and the
//! add/edit/delete UX; the backend just reads/writes the whole list.

use std::path::PathBuf;

use anyhow::{Context, Result};
use serde::{Deserialize, Serialize};
use tauri::{AppHandle, Manager};

const HOSTS_FILE: &str = "hosts.json";

/// One saved host. Fields beyond `hostname` are optional; ssh.exe will fall
/// back to `~/.ssh/config` and its own defaults for anything we don't pass.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SshHost {
    pub id: String,
    pub label: String,
    pub hostname: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub user: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub port: Option<u16>,
    #[serde(
        default,
        rename = "identityFile",
        skip_serializing_if = "Option::is_none"
    )]
    pub identity_file: Option<String>,
    #[serde(
        default,
        rename = "jumpHost",
        skip_serializing_if = "Option::is_none"
    )]
    pub jump_host: Option<String>,
    #[serde(
        default,
        rename = "extraArgs",
        skip_serializing_if = "Option::is_none"
    )]
    pub extra_args: Option<Vec<String>>,
}

fn hosts_path(app: &AppHandle) -> Result<PathBuf> {
    let dir = app
        .path()
        .app_config_dir()
        .map_err(|e| anyhow::anyhow!("app_config_dir: {e}"))?;
    Ok(dir.join(HOSTS_FILE))
}

pub fn load(app: &AppHandle) -> Result<Vec<SshHost>> {
    let path = hosts_path(app)?;
    if !path.exists() {
        return Ok(Vec::new());
    }
    let raw = std::fs::read_to_string(&path).context("read hosts.json")?;
    let hosts: Vec<SshHost> = serde_json::from_str(&raw).context("parse hosts.json")?;
    Ok(hosts)
}

pub fn save(app: &AppHandle, hosts: &[SshHost]) -> Result<()> {
    let path = hosts_path(app)?;
    if let Some(dir) = path.parent() {
        std::fs::create_dir_all(dir).context("create_dir_all")?;
    }
    let tmp = path.with_extension("json.tmp");
    let json = serde_json::to_string_pretty(hosts).context("serialize hosts")?;
    std::fs::write(&tmp, json.as_bytes()).context("write tmp hosts.json")?;
    // `std::fs::rename` is atomic on Unix and uses MoveFileEx with
    // REPLACE_EXISTING on Windows — same pattern as save_workspace.
    std::fs::rename(&tmp, &path).context("rename hosts.json")?;
    Ok(())
}