import test from "node:test";
import assert from "node:assert/strict";
import { buildView, collectViewFromText } from "../src/view.ts";
import { readOverflowSettings, type OverflowSettings } from "../settings.ts";

function settings(overrides: Partial<OverflowSettings> = {}): OverflowSettings {
	return {
		...readOverflowSettings("/nonexistent/pi-overflow.json"),
		...overrides,
	};
}

const meta = { id: "abc123def456", tool: "bash" };

function view(text: string, s = settings()) {
	return buildView(collectViewFromText(text, s), s, meta);
}

test("below threshold remains unchanged", () => {
	const out = view("line one\nline two\nline three");
	assert.ok(out.includes("line one"));
	assert.ok(out.includes("line three"));
});

test("above threshold includes header, line ranges, signal lines and tail", () => {
	const lines: string[] = [];
	for (let i = 1; i <= 1000; i++) lines.push(`row ${i} ${i === 500 ? "ERROR boom" : "ok"}`);
	const out = view(lines.join("\n"));
	assert.match(out, /\[pi-overflow id=abc123def456 tool=bash 1000 lines/);
	assert.match(out, /--- lines 1-40 ---/);
	assert.match(out, /L500: row 500 ERROR boom/);
	assert.match(out, /--- lines 881-1000 ---/);
	assert.ok(out.includes("row 1000"));
});

test("output never exceeds thresholdChars", () => {
	const lines = Array.from({ length: 5000 }, (_, i) => `line ${i} ${"x".repeat(60)}`);
	const s = settings({ thresholdChars: 2000 });
	const out = view(lines.join("\n"), s);
	assert.ok(out.length <= 2000, `view ${out.length} exceeds budget`);
	assert.ok(out.includes("line 4999"), "tail must survive");
});

test("few long lines still expose the ending", () => {
	const lines = ["start", ...Array.from({ length: 5 }, (_, i) => `middle${i} ${"y".repeat(4000)}`), "THE_END_MARKER"];
	const s = settings({ thresholdChars: 3000, headLines: 40, tailLines: 120 });
	const out = view(lines.join("\n"), s);
	assert.ok(out.includes("THE_END_MARKER"));
	assert.ok(out.length <= 3000 + 100, `view ${out.length} far exceeds budget`);
});

test("same input produces identical output", () => {
	const lines = Array.from({ length: 800 }, (_, i) => `entry ${i} ${i % 77 === 0 ? "warning" : "fine"}`);
	const text = lines.join("\n");
	assert.equal(view(text), view(text));
});

test("a single line over maxLineChars is truncated", () => {
	const long = "z".repeat(2000);
	const out = view(`a\n${long}\nb`, settings({ maxLineChars: 50 }));
	assert.ok(out.includes("z".repeat(50) + "…"));
	assert.ok(!out.includes("z".repeat(51)));
});

test("signals outrank head and survive when head+tail exceed the budget", () => {
	// ~150-char lines: head 40 + tail 120 = 160 lines * 150 = ~24K plus
	// overhead, over budget. Shrink order must keep some signals while head
	// collapses to 10 lines before the 35/65 phase kicks in.
	const lines = Array.from({ length: 400 }, (_, i) => {
		const marker = i === 200 ? "ERROR detected here" : "ok";
		return `line ${i + 1} ${marker} ${"x".repeat(140)}`;
	});
	const out = view(lines.join("\n"));
	assert.match(out, /--- signals/);
	assert.match(out, /L201: line 201 ERROR detected here/);
	// head collapsed below the configured 40 lines
	assert.match(out, /--- lines 1-(?:[0-9]|10) ---/);
	assert.ok(out.includes("line 400"));
});

test("signal hits inside the tail region are not duplicated", () => {
	const lines = Array.from({ length: 100 }, (_, i) => `line ${i + 1} ${"y".repeat(40)}`);
	lines[99] = "line 100 tail-side ERROR";
	const out = view(lines.join("\n"));
	assert.ok(!out.includes("L100:"), "tail-region hit must not appear in signals");
});