/**
 * Dev-only Vite plugin that intercepts /api/v1/* and returns mock responses.
 * Login: any username + password "password" succeeds.
 */
import type { Plugin } from 'vite';
import type { IncomingMessage, ServerResponse } from 'http';

function readBody(req: IncomingMessage): Promise<unknown> {
	return new Promise((resolve) => {
		let data = '';
		req.on('data', (chunk) => (data += chunk));
		req.on('end', () => {
			try {
				resolve(data ? JSON.parse(data) : {});
			} catch {
				resolve({});
			}
		});
	});
}

function json(res: ServerResponse, status: number, body: unknown) {
	const payload = JSON.stringify(body);
	res.writeHead(status, {
		'Content-Type': 'application/json',
		'Content-Length': Buffer.byteLength(payload),
	});
	res.end(payload);
}

function noContent(res: ServerResponse) {
	res.writeHead(204);
	res.end();
}

const MOCK_ACCESS_TOKEN = 'mock-access-token';
const MOCK_REFRESH_TOKEN = 'mock-refresh-token';

const TOKEN_PAIR = {
	access_token: MOCK_ACCESS_TOKEN,
	refresh_token: MOCK_REFRESH_TOKEN,
	expires_in: 900,
};

const ME = {
	id: 1,
	name: 'admin',
	is_admin: true,
	can_create: true,
	is_blocked: false,
};

const THUMB_COLORS = [
	'#9592B5', '#4DC7ED', '#DB6060', '#F5E872', '#7ECBA1',
	'#E08C5A', '#A67CB8', '#5A9ED4', '#C4A44A', '#6DB89E',
];

function mockThumbSvg(id: string): string {
	const color = THUMB_COLORS[id.charCodeAt(id.length - 1) % THUMB_COLORS.length];
	const label = id.slice(-4);
	return `<svg xmlns="http://www.w3.org/2000/svg" width="160" height="160">
  <rect width="160" height="160" fill="${color}"/>
  <text x="80" y="88" text-anchor="middle" font-family="monospace" font-size="18" fill="rgba(0,0,0,0.4)">${label}</text>
</svg>`;
}

const MOCK_FILES = Array.from({ length: 75 }, (_, i) => {
	const mimes = ['image/jpeg', 'image/png', 'image/webp', 'video/mp4'];
	const exts  = ['jpg',        'png',       'webp',       'mp4'      ];
	const mi = i % mimes.length;
	const id = `00000000-0000-7000-8000-${String(i + 1).padStart(12, '0')}`;
	return {
		id,
		original_name: `photo-${String(i + 1).padStart(3, '0')}.${exts[mi]}`,
		mime_type: mimes[mi],
		mime_extension: exts[mi],
		content_datetime: new Date(Date.now() - i * 3_600_000).toISOString(),
		notes: null,
		metadata: null,
		exif: {},
		phash: null,
		creator_id: 1,
		creator_name: 'admin',
		is_public: false,
		is_deleted: false,
		created_at: new Date(Date.now() - i * 3_600_000).toISOString(),
	};
});

const TAG_NAMES = [
	'nature', 'portrait', 'travel', 'architecture', 'food', 'street', 'macro',
	'landscape', 'wildlife', 'urban', 'abstract', 'black-and-white', 'night',
	'golden-hour', 'blue-hour', 'aerial', 'underwater', 'infrared', 'long-exposure',
	'panorama', 'astrophotography', 'documentary', 'editorial', 'fashion', 'wedding',
	'newborn', 'maternity', 'family', 'pet', 'sport', 'concert', 'theatre',
	'interior', 'exterior', 'product', 'still-life', 'automotive', 'aviation',
	'marine', 'industrial', 'medical', 'scientific', 'satellite', 'drone',
	'film', 'analog', 'polaroid', 'tilt-shift', 'fisheye', 'telephoto',
	'wide-angle', 'bokeh', 'silhouette', 'reflection', 'shadow', 'texture',
	'pattern', 'color', 'minimal', 'surreal', 'conceptual', 'fine-art',
	'photojournalism', 'war', 'protest', 'people', 'crowd', 'solitude',
	'children', 'elderly', 'culture', 'tradition', 'festival', 'religion',
	'asia', 'europe', 'africa', 'americas', 'oceania', 'arctic', 'desert',
	'forest', 'mountain', 'ocean', 'lake', 'river', 'waterfall', 'cave',
	'volcano', 'canyon', 'glacier', 'field', 'garden', 'park', 'city',
	'village', 'ruins', 'bridge', 'road', 'railway', 'harbor', 'airport',
	'market', 'cafe', 'restaurant', 'bar', 'museum', 'library', 'school',
	'hospital', 'church', 'mosque', 'temple', 'shrine', 'cemetery', 'stadium',
	'spring', 'summer', 'autumn', 'winter', 'rain', 'snow', 'fog', 'storm',
	'sunrise', 'sunset', 'cloudy', 'clear', 'rainbow', 'lightning', 'wind',
	'cat', 'dog', 'bird', 'horse', 'fish', 'insect', 'reptile', 'mammal',
	'flower', 'tree', 'grass', 'moss', 'mushroom', 'fruit', 'vegetable',
	'fire', 'water', 'earth', 'air', 'smoke', 'ice', 'stone', 'wood', 'metal',
	'glass', 'fabric', 'paper', 'plastic', 'ceramic', 'leather', 'concrete',
	'red', 'orange', 'yellow', 'green', 'cyan', 'blue', 'purple', 'pink',
	'brown', 'white', 'grey', 'dark', 'bright', 'pastel', 'vivid', 'muted',
	'raw', 'edited', 'hdr', 'composite', 'retouched', 'unedited', 'scanned',
	'selfie', 'candid', 'posed', 'staged', 'spontaneous', 'planned', 'series',
];

const TAG_COLORS = [
	'7ECBA1', '9592B5', '4DC7ED', 'E08C5A', 'DB6060',
	'F5E872', 'A67CB8', '5A9ED4', 'C4A44A', '6DB89E',
	'E07090', '70B0E0', 'C0A060', '80C080', 'D080B0',
];

const MOCK_CATEGORIES = [
	{ id: '00000000-0000-7000-8002-000000000001', name: 'Style', color: '9592B5', notes: null, created_at: new Date().toISOString() },
	{ id: '00000000-0000-7000-8002-000000000002', name: 'Subject', color: '4DC7ED', notes: null, created_at: new Date().toISOString() },
	{ id: '00000000-0000-7000-8002-000000000003', name: 'Location', color: '7ECBA1', notes: null, created_at: new Date().toISOString() },
	{ id: '00000000-0000-7000-8002-000000000004', name: 'Season', color: 'E08C5A', notes: null, created_at: new Date().toISOString() },
	{ id: '00000000-0000-7000-8002-000000000005', name: 'Color', color: 'DB6060', notes: null, created_at: new Date().toISOString() },
];

// Assign some tags to categories
const CATEGORY_ASSIGNMENTS: Record<string, string> = {};
TAG_NAMES.forEach((name, i) => {
	if (['film', 'analog', 'polaroid', 'bokeh', 'silhouette', 'long-exposure', 'tilt-shift', 'fisheye', 'telephoto', 'wide-angle', 'macro', 'infrared', 'hdr', 'composite'].includes(name))
		CATEGORY_ASSIGNMENTS[name] = MOCK_CATEGORIES[0].id; // Style
	else if (['portrait', 'wildlife', 'people', 'children', 'elderly', 'cat', 'dog', 'bird', 'horse', 'flower', 'tree', 'insect', 'reptile', 'mammal'].includes(name))
		CATEGORY_ASSIGNMENTS[name] = MOCK_CATEGORIES[1].id; // Subject
	else if (['asia', 'europe', 'africa', 'americas', 'oceania', 'arctic', 'desert', 'forest', 'mountain', 'ocean', 'lake', 'river', 'city', 'village'].includes(name))
		CATEGORY_ASSIGNMENTS[name] = MOCK_CATEGORIES[2].id; // Location
	else if (['spring', 'summer', 'autumn', 'winter'].includes(name))
		CATEGORY_ASSIGNMENTS[name] = MOCK_CATEGORIES[3].id; // Season
	else if (['red', 'orange', 'yellow', 'green', 'cyan', 'blue', 'purple', 'pink', 'brown', 'white', 'grey', 'dark', 'bright', 'pastel', 'vivid', 'muted'].includes(name))
		CATEGORY_ASSIGNMENTS[name] = MOCK_CATEGORIES[4].id; // Color
});

function getCategoryForId(catId: string | null) {
	if (!catId) return null;
	return MOCK_CATEGORIES.find((c) => c.id === catId) ?? null;
}

type MockTag = {
	id: string;
	name: string;
	color: string;
	notes: string | null;
	category_id: string | null;
	category_name: string | null;
	category_color: string | null;
	is_public: boolean;
	created_at: string;
};

const mockTagsArr: MockTag[] = TAG_NAMES.map((name, i) => {
	const catId = CATEGORY_ASSIGNMENTS[name] ?? null;
	const cat = getCategoryForId(catId);
	return {
		id: `00000000-0000-7000-8001-${String(i + 1).padStart(12, '0')}`,
		name,
		color: TAG_COLORS[i % TAG_COLORS.length],
		notes: null,
		category_id: catId,
		category_name: cat?.name ?? null,
		category_color: cat?.color ?? null,
		is_public: false,
		created_at: new Date(Date.now() - i * 3_600_000).toISOString(),
	};
});

// Backwards-compatible reference for existing file-tag lookups
const MOCK_TAGS = mockTagsArr;

// Tag rules: Map<tagId, Map<thenTagId, is_active>>
const tagRules = new Map<string, Map<string, boolean>>();

// Mutable in-memory state for file metadata and tags
const fileOverrides = new Map<string, Partial<typeof MOCK_FILES[0]>>();
const fileTags = new Map<string, Set<string>>(); // fileId → Set<tagId>

type MockPool = {
	id: string;
	name: string;
	notes: string | null;
	is_public: boolean;
	file_count: number;
	creator_id: number;
	creator_name: string;
	created_at: string;
};

type PoolFile = {
	id: string;
	original_name: string;
	mime_type: string;
	mime_extension: string;
	content_datetime: string;
	notes: string | null;
	metadata: null;
	exif: Record<string, unknown>;
	phash: null;
	creator_id: number;
	creator_name: string;
	is_public: boolean;
	is_deleted: boolean;
	created_at: string;
	position: number;
};

const mockPoolsArr: MockPool[] = [
	{ id: '00000000-0000-7000-8003-000000000001', name: 'Best of 2024', notes: 'Top picks from last year', is_public: false, file_count: 0, creator_id: 1, creator_name: 'admin', created_at: new Date(Date.now() - 10 * 86400000).toISOString() },
	{ id: '00000000-0000-7000-8003-000000000002', name: 'Portfolio', notes: null, is_public: true, file_count: 0, creator_id: 1, creator_name: 'admin', created_at: new Date(Date.now() - 5 * 86400000).toISOString() },
	{ id: '00000000-0000-7000-8003-000000000003', name: 'Work in Progress', notes: 'Drafts and experiments', is_public: false, file_count: 0, creator_id: 1, creator_name: 'admin', created_at: new Date(Date.now() - 2 * 86400000).toISOString() },
];

// Pool files: Map<poolId, PoolFile[]> ordered by position
const poolFilesMap = new Map<string, PoolFile[]>();

// Seed some files into first two pools
function seedPoolFiles() {
	const p1Files: PoolFile[] = MOCK_FILES.slice(0, 8).map((f, i) => ({ ...f, metadata: null, exif: {}, phash: null, position: i + 1 }));
	const p2Files: PoolFile[] = MOCK_FILES.slice(5, 14).map((f, i) => ({ ...f, metadata: null, exif: {}, phash: null, position: i + 1 }));
	poolFilesMap.set(mockPoolsArr[0].id, p1Files);
	poolFilesMap.set(mockPoolsArr[1].id, p2Files);
	mockPoolsArr[0].file_count = p1Files.length;
	mockPoolsArr[1].file_count = p2Files.length;
}
seedPoolFiles();

function getMockFile(id: string) {
	const base = MOCK_FILES.find((f) => f.id === id);
	if (!base) return null;
	return { ...base, ...(fileOverrides.get(id) ?? {}) };
}

export function mockApiPlugin(): Plugin {
	return {
		name: 'mock-api',
		configureServer(server) {
			server.middlewares.use(async (req, res, next) => {
				const url = req.url ?? '';
				const method = req.method ?? 'GET';

				if (!url.startsWith('/api/v1')) {
					return next();
				}

				const path = url.replace('/api/v1', '').split('?')[0];

				// POST /auth/login
				if (method === 'POST' && path === '/auth/login') {
					const body = (await readBody(req)) as Record<string, string>;
					if (body.password === 'password') {
						return json(res, 200, TOKEN_PAIR);
					}
					return json(res, 401, { code: 'unauthorized', message: 'Invalid credentials' });
				}

				// POST /auth/refresh
				if (method === 'POST' && path === '/auth/refresh') {
					return json(res, 200, TOKEN_PAIR);
				}

				// POST /auth/logout
				if (method === 'POST' && path === '/auth/logout') {
					return noContent(res);
				}

				// GET /auth/sessions
				if (method === 'GET' && path === '/auth/sessions') {
					return json(res, 200, {
						items: [
							{
								id: 1,
								user_agent: 'Mock Browser',
								started_at: new Date().toISOString(),
								expires_at: null,
								last_activity: new Date().toISOString(),
								is_current: true,
							},
						],
						total: 1,
					});
				}

				// GET /users/me
				if (method === 'GET' && path === '/users/me') {
					return json(res, 200, ME);
				}

				// GET /files/{id}/thumbnail
				const thumbMatch = path.match(/^\/files\/([^/]+)\/thumbnail$/);
				if (method === 'GET' && thumbMatch) {
					const svg = mockThumbSvg(thumbMatch[1]);
					res.writeHead(200, { 'Content-Type': 'image/svg+xml', 'Content-Length': Buffer.byteLength(svg) });
					return res.end(svg);
				}

				// GET /files/{id}/preview  (same SVG, just bigger)
				const previewMatch = path.match(/^\/files\/([^/]+)\/preview$/);
				if (method === 'GET' && previewMatch) {
					const id = previewMatch[1];
					const color = THUMB_COLORS[id.charCodeAt(id.length - 1) % THUMB_COLORS.length];
					const label = id.slice(-4);
					const svg = `<svg xmlns="http://www.w3.org/2000/svg" width="800" height="600">
  <rect width="800" height="600" fill="${color}"/>
  <text x="400" y="315" text-anchor="middle" font-family="monospace" font-size="48" fill="rgba(0,0,0,0.35)">${label}</text>
</svg>`;
					res.writeHead(200, { 'Content-Type': 'image/svg+xml', 'Content-Length': Buffer.byteLength(svg) });
					return res.end(svg);
				}

				// GET /files/{id}/tags
				const fileTagsGetMatch = path.match(/^\/files\/([^/]+)\/tags$/);
				if (method === 'GET' && fileTagsGetMatch) {
					const ids = fileTags.get(fileTagsGetMatch[1]) ?? new Set<string>();
					return json(res, 200, MOCK_TAGS.filter((t) => ids.has(t.id)));
				}

				// PUT /files/{id}/tags/{tag_id}  — add tag
				const fileTagPutMatch = path.match(/^\/files\/([^/]+)\/tags\/([^/]+)$/);
				if (method === 'PUT' && fileTagPutMatch) {
					const [, fid, tid] = fileTagPutMatch;
					if (!fileTags.has(fid)) fileTags.set(fid, new Set());
					fileTags.get(fid)!.add(tid);
					const ids = fileTags.get(fid)!;
					return json(res, 200, MOCK_TAGS.filter((t) => ids.has(t.id)));
				}

				// DELETE /files/{id}/tags/{tag_id}  — remove tag
				const fileTagDelMatch = path.match(/^\/files\/([^/]+)\/tags\/([^/]+)$/);
				if (method === 'DELETE' && fileTagDelMatch) {
					const [, fid, tid] = fileTagDelMatch;
					fileTags.get(fid)?.delete(tid);
					return noContent(res);
				}

				// GET /files/{id}  — single file
				const fileGetMatch = path.match(/^\/files\/([^/]+)$/);
				if (method === 'GET' && fileGetMatch) {
					const f = getMockFile(fileGetMatch[1]);
					if (!f) return json(res, 404, { code: 'not_found', message: 'File not found' });
					return json(res, 200, f);
				}

				// PATCH /files/{id}  — update metadata
				const filePatchMatch = path.match(/^\/files\/([^/]+)$/);
				if (method === 'PATCH' && filePatchMatch) {
					const id = filePatchMatch[1];
					const base = getMockFile(id);
					if (!base) return json(res, 404, { code: 'not_found', message: 'File not found' });
					const body = (await readBody(req)) as Record<string, unknown>;
					fileOverrides.set(id, { ...(fileOverrides.get(id) ?? {}), ...body });
					return json(res, 200, getMockFile(id));
				}

				// POST /files/bulk/delete  — soft delete (just remove from mock array)
				if (method === 'POST' && path === '/files/bulk/delete') {
					const body = (await readBody(req)) as { file_ids?: string[] };
					const ids = new Set(body.file_ids ?? []);
					for (let i = MOCK_FILES.length - 1; i >= 0; i--) {
						if (ids.has(MOCK_FILES[i].id)) MOCK_FILES.splice(i, 1);
					}
					return noContent(res);
				}

				// POST /files  — upload (mock: drain body, return a new fake file)
				if (method === 'POST' && path === '/files') {
					// Drain the multipart body without parsing it
					await new Promise<void>((resolve) => {
						req.on('data', () => {});
						req.on('end', resolve);
					});
					const idx = MOCK_FILES.length;
					const id = `00000000-0000-7000-8000-${String(Date.now()).slice(-12)}`;
					const ct = req.headers['content-type'] ?? '';
					// Extract filename from Content-Disposition if present (best-effort)
					const nameMatch = ct.match(/name="([^"]+)"/);
					const newFile = {
						id,
						original_name: nameMatch ? nameMatch[1] : `upload-${idx + 1}.jpg`,
						mime_type: 'image/jpeg',
						mime_extension: 'jpg',
						content_datetime: new Date().toISOString(),
						notes: null,
						metadata: null,
						exif: {},
						phash: null,
						creator_id: 1,
						creator_name: 'admin',
						is_public: false,
						is_deleted: false,
						created_at: new Date().toISOString(),
					};
					MOCK_FILES.unshift(newFile);
					return json(res, 201, newFile);
				}

				// GET /files (cursor pagination + anchor support)
				if (method === 'GET' && path === '/files') {
					const qs = new URLSearchParams(url.split('?')[1] ?? '');
					const anchor = qs.get('anchor');
					const cursor = qs.get('cursor');
					const limit = Math.min(Number(qs.get('limit') ?? 50), 200);

					if (anchor) {
						// Anchor mode: return the anchor file surrounded by neighbors
						const anchorIdx = MOCK_FILES.findIndex((f) => f.id === anchor);
						if (anchorIdx < 0) return json(res, 404, { code: 'not_found', message: 'Anchor not found' });
						const from = Math.max(0, anchorIdx - Math.floor(limit / 2));
						const slice = MOCK_FILES.slice(from, from + limit);
						const next_cursor = from + slice.length < MOCK_FILES.length
							? Buffer.from(String(from + slice.length)).toString('base64') : null;
						const prev_cursor = from > 0
							? Buffer.from(String(from)).toString('base64') : null;
						return json(res, 200, { items: slice, next_cursor, prev_cursor });
					}

					const offset = cursor ? Number(Buffer.from(cursor, 'base64').toString()) : 0;
					const slice = MOCK_FILES.slice(offset, offset + limit);
					const nextOffset = offset + slice.length;
					const next_cursor = nextOffset < MOCK_FILES.length
						? Buffer.from(String(nextOffset)).toString('base64') : null;
					return json(res, 200, { items: slice, next_cursor, prev_cursor: null });
				}

				// GET /tags/{id}/rules
				const tagRulesGetMatch = path.match(/^\/tags\/([^/]+)\/rules$/);
				if (method === 'GET' && tagRulesGetMatch) {
					const tid = tagRulesGetMatch[1];
					const ruleMap = tagRules.get(tid) ?? new Map<string, boolean>();
					const items = [...ruleMap.entries()].map(([thenId, isActive]) => {
						const t = MOCK_TAGS.find((x) => x.id === thenId);
						return { tag_id: tid, then_tag_id: thenId, then_tag_name: t?.name ?? null, is_active: isActive };
					});
					return json(res, 200, items);
				}

				// POST /tags/{id}/rules
				const tagRulesPostMatch = path.match(/^\/tags\/([^/]+)\/rules$/);
				if (method === 'POST' && tagRulesPostMatch) {
					const tid = tagRulesPostMatch[1];
					const body = (await readBody(req)) as Record<string, unknown>;
					const thenId = body.then_tag_id as string;
					const isActive = body.is_active !== false;
					if (!tagRules.has(tid)) tagRules.set(tid, new Map());
					tagRules.get(tid)!.set(thenId, isActive);
					const t = MOCK_TAGS.find((x) => x.id === thenId);
					return json(res, 201, { tag_id: tid, then_tag_id: thenId, then_tag_name: t?.name ?? null, is_active: isActive });
				}

				// PATCH /tags/{id}/rules/{then_id}  — activate / deactivate
				const tagRulesPatchMatch = path.match(/^\/tags\/([^/]+)\/rules\/([^/]+)$/);
				if (method === 'PATCH' && tagRulesPatchMatch) {
					const [, tid, thenId] = tagRulesPatchMatch;
					const body = (await readBody(req)) as Record<string, unknown>;
					const isActive = body.is_active as boolean;
					const ruleMap = tagRules.get(tid);
					if (!ruleMap?.has(thenId)) return json(res, 404, { code: 'not_found', message: 'Rule not found' });
					ruleMap.set(thenId, isActive);
					const t = MOCK_TAGS.find((x) => x.id === thenId);
					return json(res, 200, { tag_id: tid, then_tag_id: thenId, then_tag_name: t?.name ?? null, is_active: isActive });
				}

				// DELETE /tags/{id}/rules/{then_id}
				const tagRulesDelMatch = path.match(/^\/tags\/([^/]+)\/rules\/([^/]+)$/);
				if (method === 'DELETE' && tagRulesDelMatch) {
					const [, tid, thenId] = tagRulesDelMatch;
					tagRules.get(tid)?.delete(thenId);
					return noContent(res);
				}

				// GET /tags/{id}
				const tagGetMatch = path.match(/^\/tags\/([^/]+)$/);
				if (method === 'GET' && tagGetMatch) {
					const t = MOCK_TAGS.find((x) => x.id === tagGetMatch[1]);
					if (!t) return json(res, 404, { code: 'not_found', message: 'Tag not found' });
					return json(res, 200, t);
				}

				// PATCH /tags/{id}
				const tagPatchMatch = path.match(/^\/tags\/([^/]+)$/);
				if (method === 'PATCH' && tagPatchMatch) {
					const idx = MOCK_TAGS.findIndex((x) => x.id === tagPatchMatch[1]);
					if (idx < 0) return json(res, 404, { code: 'not_found', message: 'Tag not found' });
					const body = (await readBody(req)) as Partial<MockTag>;
					const catId = body.category_id ?? MOCK_TAGS[idx].category_id;
					const cat = getCategoryForId(catId);
					Object.assign(MOCK_TAGS[idx], {
						...body,
						category_name: cat?.name ?? null,
						category_color: cat?.color ?? null,
					});
					return json(res, 200, MOCK_TAGS[idx]);
				}

				// DELETE /tags/{id}
				const tagDelMatch = path.match(/^\/tags\/([^/]+)$/);
				if (method === 'DELETE' && tagDelMatch) {
					const idx = MOCK_TAGS.findIndex((x) => x.id === tagDelMatch[1]);
					if (idx >= 0) MOCK_TAGS.splice(idx, 1);
					return noContent(res);
				}

				// GET /tags
				if (method === 'GET' && path === '/tags') {
					const qs = new URLSearchParams(url.split('?')[1] ?? '');
					const search = qs.get('search')?.toLowerCase() ?? '';
					const sort = qs.get('sort') ?? 'name';
					const order = qs.get('order') ?? 'asc';
					const limit = Math.min(Number(qs.get('limit') ?? 100), 500);
					const offset = Number(qs.get('offset') ?? 0);

					let filtered = search
						? MOCK_TAGS.filter((t) => t.name.toLowerCase().includes(search))
						: [...MOCK_TAGS];

					filtered.sort((a, b) => {
						let av: string, bv: string;
						if (sort === 'color') { av = a.color; bv = b.color; }
						else if (sort === 'category_name') { av = a.category_name ?? ''; bv = b.category_name ?? ''; }
						else if (sort === 'created') { av = a.created_at; bv = b.created_at; }
						else { av = a.name; bv = b.name; }
						const cmp = av.localeCompare(bv);
						return order === 'desc' ? -cmp : cmp;
					});

					const items = filtered.slice(offset, offset + limit);
					return json(res, 200, { items, total: filtered.length, offset, limit });
				}

				// POST /tags
				if (method === 'POST' && path === '/tags') {
					const body = (await readBody(req)) as Partial<MockTag>;
					const catId = body.category_id ?? null;
					const cat = getCategoryForId(catId);
					const newTag: MockTag = {
						id: `00000000-0000-7000-8001-${String(Date.now()).slice(-12)}`,
						name: body.name ?? 'Unnamed',
						color: body.color ?? '444455',
						notes: body.notes ?? null,
						category_id: catId,
						category_name: cat?.name ?? null,
						category_color: cat?.color ?? null,
						is_public: body.is_public ?? false,
						created_at: new Date().toISOString(),
					};
					MOCK_TAGS.unshift(newTag);
					return json(res, 201, newTag);
				}

				// GET /categories/{id}/tags
				const catTagsMatch = path.match(/^\/categories\/([^/]+)\/tags$/);
				if (method === 'GET' && catTagsMatch) {
					const catId = catTagsMatch[1];
					const qs = new URLSearchParams(url.split('?')[1] ?? '');
					const limit = Math.min(Number(qs.get('limit') ?? 100), 500);
					const offset = Number(qs.get('offset') ?? 0);
					const all = MOCK_TAGS.filter((t) => t.category_id === catId);
					all.sort((a, b) => a.name.localeCompare(b.name));
					const items = all.slice(offset, offset + limit);
					return json(res, 200, { items, total: all.length, offset, limit });
				}

				// GET /categories/{id}
				const catGetMatch = path.match(/^\/categories\/([^/]+)$/);
				if (method === 'GET' && catGetMatch) {
					const cat = MOCK_CATEGORIES.find((c) => c.id === catGetMatch[1]);
					if (!cat) return json(res, 404, { code: 'not_found', message: 'Category not found' });
					return json(res, 200, cat);
				}

				// PATCH /categories/{id}
				const catPatchMatch = path.match(/^\/categories\/([^/]+)$/);
				if (method === 'PATCH' && catPatchMatch) {
					const idx = MOCK_CATEGORIES.findIndex((c) => c.id === catPatchMatch[1]);
					if (idx < 0) return json(res, 404, { code: 'not_found', message: 'Category not found' });
					const body = (await readBody(req)) as Partial<typeof MOCK_CATEGORIES[0]>;
					Object.assign(MOCK_CATEGORIES[idx], body);
					// Sync category_name/color on affected tags
					const cat = MOCK_CATEGORIES[idx];
					for (const t of MOCK_TAGS) {
						if (t.category_id === cat.id) {
							t.category_name = cat.name;
							t.category_color = cat.color;
						}
					}
					return json(res, 200, MOCK_CATEGORIES[idx]);
				}

				// DELETE /categories/{id}
				const catDelMatch = path.match(/^\/categories\/([^/]+)$/);
				if (method === 'DELETE' && catDelMatch) {
					const idx = MOCK_CATEGORIES.findIndex((c) => c.id === catDelMatch[1]);
					if (idx >= 0) {
						const catId = MOCK_CATEGORIES[idx].id;
						MOCK_CATEGORIES.splice(idx, 1);
						for (const t of MOCK_TAGS) {
							if (t.category_id === catId) {
								t.category_id = null;
								t.category_name = null;
								t.category_color = null;
							}
						}
					}
					return noContent(res);
				}

				// GET /categories
				if (method === 'GET' && path === '/categories') {
					const qs = new URLSearchParams(url.split('?')[1] ?? '');
					const search = qs.get('search')?.toLowerCase() ?? '';
					const sort = qs.get('sort') ?? 'name';
					const order = qs.get('order') ?? 'asc';
					const limit = Math.min(Number(qs.get('limit') ?? 50), 500);
					const offset = Number(qs.get('offset') ?? 0);

					let filtered = search
						? MOCK_CATEGORIES.filter((c) => c.name.toLowerCase().includes(search))
						: [...MOCK_CATEGORIES];

					filtered.sort((a, b) => {
						let av: string, bv: string;
						if (sort === 'color') { av = a.color; bv = b.color; }
						else if (sort === 'created') { av = a.created_at; bv = b.created_at; }
						else { av = a.name; bv = b.name; }
						const cmp = av.localeCompare(bv);
						return order === 'desc' ? -cmp : cmp;
					});

					const items = filtered.slice(offset, offset + limit);
					return json(res, 200, { items, total: filtered.length, offset, limit });
				}

				// POST /categories
				if (method === 'POST' && path === '/categories') {
					const body = (await readBody(req)) as Partial<typeof MOCK_CATEGORIES[0]>;
					const newCat = {
						id: `00000000-0000-7000-8002-${String(Date.now()).slice(-12)}`,
						name: body.name ?? 'Unnamed',
						color: body.color ?? '9592B5',
						notes: body.notes ?? null,
						created_at: new Date().toISOString(),
					};
					MOCK_CATEGORIES.unshift(newCat);
					return json(res, 201, newCat);
				}

				// GET /pools/{id}/files
				const poolFilesGetMatch = path.match(/^\/pools\/([^/]+)\/files$/);
				if (method === 'GET' && poolFilesGetMatch) {
					const pid = poolFilesGetMatch[1];
					if (!mockPoolsArr.find((p) => p.id === pid))
						return json(res, 404, { code: 'not_found', message: 'Pool not found' });
					const qs = new URLSearchParams(url.split('?')[1] ?? '');
					const limit = Math.min(Number(qs.get('limit') ?? 50), 200);
					const cursor = qs.get('cursor');
					const files = poolFilesMap.get(pid) ?? [];
					const offset = cursor ? Number(Buffer.from(cursor, 'base64').toString()) : 0;
					const slice = files.slice(offset, offset + limit);
					const nextOffset = offset + slice.length;
					const next_cursor = nextOffset < files.length
						? Buffer.from(String(nextOffset)).toString('base64') : null;
					return json(res, 200, { items: slice, next_cursor, prev_cursor: null });
				}

				// POST /pools/{id}/files/remove
				const poolFilesRemoveMatch = path.match(/^\/pools\/([^/]+)\/files\/remove$/);
				if (method === 'POST' && poolFilesRemoveMatch) {
					const pid = poolFilesRemoveMatch[1];
					const pool = mockPoolsArr.find((p) => p.id === pid);
					if (!pool) return json(res, 404, { code: 'not_found', message: 'Pool not found' });
					const body = (await readBody(req)) as { file_ids?: string[] };
					const toRemove = new Set(body.file_ids ?? []);
					const files = poolFilesMap.get(pid) ?? [];
					const updated = files.filter((f) => !toRemove.has(f.id));
					// Reassign positions
					updated.forEach((f, i) => { f.position = i + 1; });
					poolFilesMap.set(pid, updated);
					pool.file_count = updated.length;
					return noContent(res);
				}

				// PUT /pools/{id}/files/reorder
				const poolReorderMatch = path.match(/^\/pools\/([^/]+)\/files\/reorder$/);
				if (method === 'PUT' && poolReorderMatch) {
					const pid = poolReorderMatch[1];
					const pool = mockPoolsArr.find((p) => p.id === pid);
					if (!pool) return json(res, 404, { code: 'not_found', message: 'Pool not found' });
					const body = (await readBody(req)) as { file_ids?: string[] };
					const order = body.file_ids ?? [];
					const files = poolFilesMap.get(pid) ?? [];
					const byId = new Map(files.map((f) => [f.id, f]));
					const reordered: PoolFile[] = [];
					for (const id of order) {
						const f = byId.get(id);
						if (f) reordered.push(f);
					}
					reordered.forEach((f, i) => { f.position = i + 1; });
					poolFilesMap.set(pid, reordered);
					return noContent(res);
				}

				// POST /pools/{id}/files  — add files
				const poolFilesAddMatch = path.match(/^\/pools\/([^/]+)\/files$/);
				if (method === 'POST' && poolFilesAddMatch) {
					const pid = poolFilesAddMatch[1];
					const pool = mockPoolsArr.find((p) => p.id === pid);
					if (!pool) return json(res, 404, { code: 'not_found', message: 'Pool not found' });
					const body = (await readBody(req)) as { file_ids?: string[] };
					const files = poolFilesMap.get(pid) ?? [];
					const existing = new Set(files.map((f) => f.id));
					let pos = files.length;
					for (const fid of (body.file_ids ?? [])) {
						if (existing.has(fid)) continue;
						const base = MOCK_FILES.find((f) => f.id === fid);
						if (!base) continue;
						pos++;
						files.push({ ...base, metadata: null, exif: {}, phash: null, position: pos });
						existing.add(fid);
					}
					poolFilesMap.set(pid, files);
					pool.file_count = files.length;
					return noContent(res);
				}

				// GET /pools/{id}
				const poolGetMatch = path.match(/^\/pools\/([^/]+)$/);
				if (method === 'GET' && poolGetMatch) {
					const pool = mockPoolsArr.find((p) => p.id === poolGetMatch[1]);
					if (!pool) return json(res, 404, { code: 'not_found', message: 'Pool not found' });
					return json(res, 200, pool);
				}

				// PATCH /pools/{id}
				const poolPatchMatch = path.match(/^\/pools\/([^/]+)$/);
				if (method === 'PATCH' && poolPatchMatch) {
					const pool = mockPoolsArr.find((p) => p.id === poolPatchMatch[1]);
					if (!pool) return json(res, 404, { code: 'not_found', message: 'Pool not found' });
					const body = (await readBody(req)) as Partial<MockPool>;
					Object.assign(pool, body);
					return json(res, 200, pool);
				}

				// DELETE /pools/{id}
				const poolDelMatch = path.match(/^\/pools\/([^/]+)$/);
				if (method === 'DELETE' && poolDelMatch) {
					const idx = mockPoolsArr.findIndex((p) => p.id === poolDelMatch[1]);
					if (idx >= 0) {
						poolFilesMap.delete(mockPoolsArr[idx].id);
						mockPoolsArr.splice(idx, 1);
					}
					return noContent(res);
				}

				// GET /pools
				if (method === 'GET' && path === '/pools') {
					const qs = new URLSearchParams(url.split('?')[1] ?? '');
					const search = qs.get('search')?.toLowerCase() ?? '';
					const sort = qs.get('sort') ?? 'created';
					const order = qs.get('order') ?? 'desc';
					const limit = Math.min(Number(qs.get('limit') ?? 50), 200);
					const offset = Number(qs.get('offset') ?? 0);

					let filtered = search
						? mockPoolsArr.filter((p) => p.name.toLowerCase().includes(search))
						: [...mockPoolsArr];

					filtered.sort((a, b) => {
						const av = sort === 'name' ? a.name : a.created_at;
						const bv = sort === 'name' ? b.name : b.created_at;
						const cmp = av.localeCompare(bv);
						return order === 'desc' ? -cmp : cmp;
					});

					const items = filtered.slice(offset, offset + limit);
					return json(res, 200, { items, total: filtered.length, offset, limit });
				}

				// POST /pools
				if (method === 'POST' && path === '/pools') {
					const body = (await readBody(req)) as Partial<MockPool>;
					const newPool: MockPool = {
						id: `00000000-0000-7000-8003-${String(Date.now()).slice(-12)}`,
						name: body.name ?? 'Unnamed',
						notes: body.notes ?? null,
						is_public: body.is_public ?? false,
						file_count: 0,
						creator_id: 1,
						creator_name: 'admin',
						created_at: new Date().toISOString(),
					};
					mockPoolsArr.unshift(newPool);
					return json(res, 201, newPool);
				}

				// Fallback: 404
				return json(res, 404, { code: 'not_found', message: `Mock: no handler for ${method} ${path}` });
			});
		},
	};
}