import { describe, it, expect } from 'vitest';
import { buildLayout, NODE_H, ROW_GAP } from './buildLayout';
import type { components } from '$lib/generated/api';

type PersonNodeDTO = components['schemas']['PersonNodeDTO'];
type RelationshipDTO = components['schemas']['RelationshipDTO'];

const PARENT = '00000000-0000-0000-0000-000000000001';
const CHILD = '00000000-0000-0000-0000-000000000002';
const SPOUSE_A = '00000000-0000-0000-0000-000000000003';
const SPOUSE_B = '00000000-0000-0000-0000-000000000004';
const NEGATIVE_A = '00000000-0000-0000-0000-000000000005';
const NEGATIVE_B = '00000000-0000-0000-0000-000000000006';
const NEGATIVE_C = '00000000-0000-0000-0000-000000000007';

function node(id: string, displayName: string, generation: number | null = null): PersonNodeDTO {
	return generation == null
		? { id, displayName, familyMember: true }
		: { id, displayName, familyMember: true, generation };
}

function parentEdge(parentId: string, childId: string, id = parentId + childId): RelationshipDTO {
	return {
		id,
		personId: parentId,
		relatedPersonId: childId,
		personDisplayName: '',
		relatedPersonDisplayName: '',
		relationType: 'PARENT_OF'
	};
}

function spouseEdge(a: string, b: string, id = a + b): RelationshipDTO {
	return {
		id,
		personId: a,
		relatedPersonId: b,
		personDisplayName: '',
		relatedPersonDisplayName: '',
		relationType: 'SPOUSE_OF'
	};
}

function yOf(layout: ReturnType<typeof buildLayout>, id: string): number {
	const p = layout.positions.get(id);
	if (!p) throw new Error(`No position for ${id}`);
	return p.y;
}

describe('buildLayout — generation seeding (#689)', () => {
	it('Herbert Cram regression: two parented G=3 spouses share the same row', () => {
		// Both Herbert (G 3) and Clara (G 3) are parented children of their respective
		// G 2 ancestors. They are spouses. Before #689 the iterative longest-path put
		// Herbert one row deeper than Clara via the spouse-pulldown of his loose parent.
		// With imported generation as a strict seed both render at the same y.
		const layout = buildLayout(
			[node(SPOUSE_A, 'Herbert', 3), node(SPOUSE_B, 'Clara', 3)],
			[spouseEdge(SPOUSE_A, SPOUSE_B)]
		);

		expect(yOf(layout, SPOUSE_A)).toBe(yOf(layout, SPOUSE_B));
	});

	it('strict-seed override: imported generation pins rank even when parent edges imply deeper', () => {
		// PARENT has no explicit generation → falls back to 0. CHILD is parented under
		// PARENT but has imported generation = 3. The seeded rank wins; the heuristic
		// must not push CHILD to rank 1.
		const layout = buildLayout(
			[node(PARENT, 'Parent'), node(CHILD, 'Child', 3)],
			[parentEdge(PARENT, CHILD)]
		);

		expect(yOf(layout, CHILD)).toBe(3 * (NODE_H + ROW_GAP));
	});

	it('fallback inherits seeded parent rank: G 2 parent → null-gen child lands at rank 3', () => {
		// CHILD has no imported generation. PARENT has generation = 2. The fallback
		// reads PARENT's rank from the unified rank map (2) and computes 2 + 1 = 3.
		const layout = buildLayout(
			[node(PARENT, 'Parent', 2), node(CHILD, 'Child')],
			[parentEdge(PARENT, CHILD)]
		);

		expect(yOf(layout, CHILD)).toBe(3 * (NODE_H + ROW_GAP));
	});

	it('normalise is a no-op when all ranks are non-negative', () => {
		// Seeded ranks [3, 4, 5] → y must reflect [3, 4, 5] without any shift.
		const G3 = '00000000-0000-0000-0000-000000000031';
		const G4 = '00000000-0000-0000-0000-000000000032';
		const G5 = '00000000-0000-0000-0000-000000000033';
		const layout = buildLayout(
			[node(G3, 'three', 3), node(G4, 'four', 4), node(G5, 'five', 5)],
			[]
		);

		expect(yOf(layout, G3)).toBe(3 * (NODE_H + ROW_GAP));
		expect(yOf(layout, G4)).toBe(4 * (NODE_H + ROW_GAP));
		expect(yOf(layout, G5)).toBe(5 * (NODE_H + ROW_GAP));
	});

	it('normalise shifts negative seeds so min rank becomes 0', () => {
		// Seeded ranks [-1, 0, 1] → after shift they render at [0, 1, 2] y-rows.
		const layout = buildLayout(
			[node(NEGATIVE_A, 'minus-one', -1), node(NEGATIVE_B, 'zero', 0), node(NEGATIVE_C, 'one', 1)],
			[]
		);

		expect(yOf(layout, NEGATIVE_A)).toBe(0);
		expect(yOf(layout, NEGATIVE_B)).toBe(1 * (NODE_H + ROW_GAP));
		expect(yOf(layout, NEGATIVE_C)).toBe(2 * (NODE_H + ROW_GAP));
	});
});