// M15: `pi-roost list`, a table for people (`--json` is for programs).
// (not pi-tui: the CLI runs without pi's packages)
import { truncateToWidth, visibleWidth } from "./text-width.ts";
import type { JobRow } from "./protocol.ts";
import { ageOf, groupOf, listed, sentenceOf, shortPath } from "./view-model.ts";

const ORDER = { pinned: 0, ready: 1, "needs-input": 2, working: 3, completed: 4 } as const;
const oneLine = (s: string) => s.replace(/[\u0000-\u001f\u007f]+/g, " ").replace(/\s+/g, " ").trim();

export interface ListOptions {
	now?: number;
	width?: number;
	/** Also the subagents sessions spawned (the agent view leaves them out, M13). */
	subagents?: boolean;
	home?: string;
}

/** Rows as the agent view would list them: waiting first, then working, then the rest by when they ended. */
export function formatList(rows: JobRow[], opts: ListOptions = {}): string {
	const now = opts.now ?? Date.now();
	const width = Math.max(40, opts.width ?? 100);
	const shown = rows
		.filter((r) => opts.subagents || listed(r))
		.sort((a, b) => ORDER[groupOf(a)] - ORDER[groupOf(b)] || (b.endedAt ?? b.stateSince) - (a.endedAt ?? a.stateSince));
	if (shown.length === 0) return "no background sessions\n";
	const state = (r: JobRow) => (r.state === "blocked" ? "waiting" : r.state === "working" && r.status === "busy" ? "working" : r.state);
	const cells = shown.map((r) => ({
		id: r.id,
		state: `${r.pid !== null ? "●" : "∙"} ${state(r)}`,
		name: `${r.parentSession ? "↳ " : ""}${oneLine(r.name)}`,
		age: ageOf(r, now),
		what: oneLine(r.state === "blocked" && r.question ? r.question : sentenceOf(r)),
		dir: shortPath(r.cwd, opts.home),
	}));
	const w = (k: keyof (typeof cells)[number], max: number) => Math.min(max, Math.max(k.length, ...cells.map((c) => visibleWidth(c[k]))));
	const cols = { id: w("id", 8), state: w("state", 10), name: w("name", 30), age: w("age", 6), dir: w("dir", 28) };
	const fixed = cols.id + cols.state + cols.name + cols.age + cols.dir + 10;
	const whatW = Math.max(10, width - fixed);
	const pad = (s: string, n: number) => {
		const t = truncateToWidth(s, n, "…");
		return t + " ".repeat(Math.max(0, n - visibleWidth(t)));
	};
	const line = (c: { id: string; state: string; name: string; age: string; what: string; dir: string }) =>
		[pad(c.id, cols.id), pad(c.state, cols.state), pad(c.name, cols.name), pad(c.age, cols.age), pad(c.what, whatW), truncateToWidth(c.dir, cols.dir, "…")].join("  ").trimEnd();
	const fit = (l: string) => truncateToWidth(l, width, "…");
	const head = line({ id: "ID", state: "STATE", name: "NAME", age: "AGE", what: "ACTIVITY", dir: "DIR" });
	const hidden = rows.length - shown.length;
	const foot = hidden > 0 && !opts.subagents ? `\n${hidden} subagent${hidden === 1 ? "" : "s"} not shown (--subagents)` : "";
	return `${[head, ...cells.map(line)].map(fit).join("\n")}${foot}\n`;
}