import { SessionManifest } from './protocol';

/** Time in the current process generation; never keep aging a stopped session. */

export function sessionAge(manifest: SessionManifest, now = Date.now()): string | undefined {

const end = manifest.status === 'exited' ? manifest.ended : now;

if (!Number.isFinite(manifest.created) || end === undefined || !Number.isFinite(end)) { return undefined; }

const minutes = Math.floor(Math.max(0, end - manifest.created) / 60000);

return minutes < 1 ? '<1m' : minutes < 60 ? `${minutes}m` : minutes < 1440 ? `${Math.floor(minutes / 60)}h` : `${Math.floor(minutes / 1440)}d`;

}

/** Public session details; never include connection credentials. */

export function sessionPresentation(manifest: SessionManifest, connected: boolean | undefined, control: boolean, restarting = false,

directory = manifest.directory): { state: string; label: string; description: string; detail: string; tooltip: string } {

const state = restarting ? 'restarting' : manifest.status === 'exited' ? 'stopped' : connected === false ? 'disconnected'

: manifest.status === 'input' ? 'waiting for input' : manifest.status;

const provider = manifest.provider === 'r' ? 'plain' : manifest.provider === 'arf-existing' ? 'arf (attached)' : 'arf';

const version = manifest.rVersion?.match(/^R version (\S+)/)?.[1];

const supervision = manifest.supervision === 'detached' ? 'Independent process' : manifest.supervision;

const age = sessionAge(manifest);

return {

state,

label: `R: ${manifest.label} · ${state}`,

// Description is inline (and doubles as the native button tooltip); detail

// gets a second picker row. Neither supports arbitrary multiline content.

description: `${version ? `R ${version}` : 'R'} · ${provider} · PID ${manifest.rPid ?? 'pending'}${age ? ` · ${age}` : ''}${connected && !control ? ' · observing' : ''}`,

detail: `${directory} · ${manifest.host} · ${supervision}`,

// The full details remain available in the status bar hover and Session Details.

tooltip: [

manifest.label,

`State: ${state}`,

`Connection: ${connected === undefined ? 'Not open in this VS Code window' : connected

? `Connected · ${control ? 'controlling' : 'observing'}` : 'Disconnected'}`,

`Provider: ${manifest.provider === 'r' ? 'Plain R' : manifest.provider === 'arf-existing' ? 'Attached arf' : 'Headless arf'}`,

manifest.rVersion ?? 'R version: pending',

`PID: ${manifest.rPid ?? 'pending'}`,

...(age ? [`${manifest.status === 'exited' ? 'Lifetime' : 'Session age'}: ${age}`] : []),

...(Number.isFinite(manifest.created) ? [`Started: ${new Date(manifest.created).toLocaleString()}`] : []),

`Working directory: ${directory}`,

`Host: ${manifest.host}`,

`Process supervision: ${supervision}${manifest.supervision === 'detached' ? ' (survives VS Code reload/exit)' : ''}`,

...(manifest.rPath ? [`R executable: ${manifest.rPath}`] : []),

`Session: ${manifest.id.slice(0, 8)}`,

].join('\n'),

};

}