import { Actor } from '@nestri/core/actor';
import { Box } from '@nestri/core/box/index';
import { ErrorCodes, VisibleError } from '@nestri/core/error';
import { Examples } from '@nestri/core/examples';
import { Identifier } from '@nestri/core/id';
import { Machine } from '@nestri/core/machine/index';
import { Team } from '@nestri/core/team/index';
import { Member } from '@nestri/core/team/member';
import { Hono } from 'hono';
import { describeRoute } from 'hono-openapi';
import { z } from 'zod';

import { ErrorResponses, machineOnly, notPublic, Result, validator } from '../utils';

/**
 * Host registration.
 *
 * A box does not get to say who it is. It registers once against its owner's
 * session, is handed an id and a secret, and authenticates as itself from then
 * on — so `hostId` on a download report is something the API assigned rather
 * than a free-form string any holder of a shared secret could invent.
 */
export namespace MachineApi {
	export const route = new Hono()
		.post(
			'/register',
			notPublic,
			describeRoute({
				tags: ['Machine'],
				summary: 'Register a nessh host',
				description:
					'Exchange the calling user session for a machine id and secret. The secret is returned once and never again — it is stored only as a digest.',
				responses: {
					200: {
						content: {
							'application/json': {
								schema: Result(
									z.object({
										machineId: z.string().meta({ example: Examples.Machine.id }),
										secret: z.string().meta({
											description: 'Shown once. Store it on the box; it cannot be retrieved.'
										})
									})
								)
							}
						},
						description: 'The box is registered'
					},
					401: ErrorResponses[401],
					403: ErrorResponses[403]
				}
			}),
			validator(
				'json',
				z.object({
					label: z.string().min(1).max(64).meta({
						description: 'Human-readable name for the box',
						example: Examples.Machine.label
					}),
					teamId: z.string().optional().meta({
						description:
							'Team to own this hardware. Defaults to the caller’s personal team, which always exists'
					})
				})
			),
			async (c) => {
				const { label, teamId } = c.req.valid('json');

				// `notPublic` also admits admin, which has no user to own the box.
				// Registering is an act of ownership, so it needs a real one.
				const actor = Actor.use();
				if (actor.type !== 'user' && actor.type !== 'member') {
					throw new VisibleError(
						'forbidden',
						ErrorCodes.Permission.INSUFFICIENT_PERMISSIONS,
						'Registering a machine requires a user session'
					);
				}

				// A team has to be resolved rather than defaulted to null, because
				// `machine.teamId` is notNull. The order is: what the caller asked
				// for, then the team they are acting inside, then their personal
				// team — which `ensurePersonal` makes if this is an older user who
				// has none. ref(d-0048)
				const owningTeam =
					teamId ??
					(actor.type === 'member'
						? actor.properties.teamID
						: await Team.ensurePersonal({ displayName: Actor.userID }));

				// A caller naming a team must belong to it. Without this, `teamId`
				// would be a way to park hardware in somebody else's team.
				if (teamId) {
					const membership = await Member.findByTeamAndUser({
						teamId,
						userId: Actor.userID
					});
					if (!membership) {
						throw new VisibleError(
							'forbidden',
							ErrorCodes.Permission.FORBIDDEN,
							'You are not a member of that team'
						);
					}
				}

				const registered = await Machine.register({
					id: Identifier.ascending('machine'),
					ownerUserId: Actor.userID,
					teamId: owningTeam,
					label
				});

				return c.json({ data: { machineId: registered.id, secret: registered.secret } });
			}
		)
		.patch(
			'/:id',
			notPublic,
			describeRoute({
				tags: ['Machine'],
				summary: 'Move a box to another team',
				description:
					'Move a machine you own to a team you belong to. Hardware always belongs to exactly one team, so there is no way to unscope — name your personal team instead. This is not ownership transfer: the owner does not change.',
				responses: {
					200: {
						content: { 'application/json': { schema: Result(Machine.Info) } },
						description: 'The machine, rescoped'
					},
					401: ErrorResponses[401],
					403: ErrorResponses[403],
					404: ErrorResponses[404]
				}
			}),
			validator(
				'json',
				z.object({
					teamId: z.string().meta({
						description:
							'Team to move the box to. There is no “no team” — to unscope, name your personal team'
					})
				})
			),
			async (c) => {
				const { teamId } = c.req.valid('json');

				const actor = Actor.use();
				if (actor.type !== 'user' && actor.type !== 'member') {
					throw new VisibleError(
						'forbidden',
						ErrorCodes.Permission.INSUFFICIENT_PERMISSIONS,
						'Rescoping a machine requires a user session'
					);
				}

				// Verified before the write. `setTeam` scopes to the owner but
				// knows nothing about who belongs to the target team, so this is
				// the only place that check exists.
				const membership = await Member.findByTeamAndUser({
					teamId,
					userId: Actor.userID
				});
				if (!membership) {
					throw new VisibleError(
						'forbidden',
						ErrorCodes.Permission.FORBIDDEN,
						'You are not a member of that team'
					);
				}

				const machine = await Machine.setTeam({
					id: c.req.param('id'),
					ownerUserId: Actor.userID,
					teamId
				});
				if (!machine) {
					// Owner-scoped in the query, so someone else's machine is a
					// 404 rather than a 403 — no way to probe for ids.
					throw new VisibleError(
						'not_found',
						ErrorCodes.NotFound.RESOURCE_NOT_FOUND,
						'No such machine, or it is not yours'
					);
				}
				return c.json({ data: machine });
			}
		)
		.get(
			'/entitlement',
			machineOnly,
			describeRoute({
				tags: ['Machine'],
				summary: 'Ask whether a user may use this box',
				description:
					'Answers for the calling machine only — the machine is taken from its credentials, never from the query, so a box cannot ask about another. Membership is read live, so removing someone from a team removes their access.',
				responses: {
					200: {
						content: { 'application/json': { schema: Result(Machine.Entitlement) } },
						description: 'Whether the user may use this machine, and why'
					},
					403: ErrorResponses[403]
				}
			}),
			validator('query', z.object({ userId: z.string().min(1) })),
			async (c) => {
				const { userId } = c.req.valid('query');
				return c.json({
					data: await Machine.entitlement({ machineId: Actor.machineID, userId })
				});
			}
		)
		.post(
			'/heartbeat',
			machineOnly,
			describeRoute({
				tags: ['Machine'],
				summary: 'Say the host is alive',
				description:
					'Records liveness for the calling machine and returns how often it should call back. The interval comes from the server on purpose: a fleet whose cadence can only change by shipping a new agent is a fleet whose cadence never changes. The body carries one optional fact — where this host can be reached — because only a host can say that about itself and this is the call it already makes as itself. What a host is *running* is reported separately.',
				responses: {
					200: {
						content: {
							'application/json': {
								schema: Result(
									z.object({
										lastSeen: z.iso.datetime().meta({
											description: 'When this beat was recorded, by the database’s clock',
											example: Examples.Machine.lastSeen
										}),
										intervalSeconds: z.number().meta({
											description: 'Call back this often',
											example: Machine.HEARTBEAT_SECONDS
										})
									})
								)
							}
						},
						description: 'The beat was recorded'
					},
					400: ErrorResponses[400],
					403: ErrorResponses[403],
					404: ErrorResponses[404],
					409: ErrorResponses[409]
				}
			}),
			validator(
				'json',
				z
					.object({
						endpointId: Machine.EndpointId.optional().meta({
							description:
								'Where this host can be reached, as its own endpoint id. Omit it and the stored value is left alone — a host that does not mention where it is has not moved, and an absent field must never read as "nowhere"',
							example: Examples.Machine.endpointId
						})
					})
					// A host that has nothing to add sends no body at all, which
					// is what every agent shipped before this field did.
					.optional()
			),
			async (c) => {
				const body = c.req.valid('json');
				const lastSeen = await Machine.touchLastSeen({
					id: Actor.machineID,
					endpointId: body?.endpointId
				});
				if (!lastSeen) {
					// The credentials authenticated but the row is gone — a host
					// deleted mid-beat. It must re-register rather than keep
					// beating into nothing, so this is a 404 and not a 200.
					throw new VisibleError(
						'not_found',
						ErrorCodes.NotFound.RESOURCE_NOT_FOUND,
						'This machine no longer exists'
					);
				}
				return c.json({
					data: {
						lastSeen: lastSeen.toISOString(),
						intervalSeconds: Machine.HEARTBEAT_SECONDS
					}
				});
			}
		)
		.post(
			'/report',
			machineOnly,
			describeRoute({
				tags: ['Machine'],
				summary: 'Say what the host is running',
				description:
					'Records one full snapshot of the boxes on the calling host. Separate from the beat because the two have different loss tolerance: a dropped report is corrected by the next one, where a dropped beat moves a host towards offline. Send one when a box changes lifecycle, and send one anyway every so often so a single lost snapshot cannot leave this record permanently wrong. Never send a delta — a retrying agent cannot promise ordering, and out-of-order deltas describe a host that never existed.',
				responses: {
					200: {
						content: { 'application/json': { schema: Result(Box.ReportOutcome) } },
						description: 'The snapshot was recorded'
					},
					400: ErrorResponses[400],
					403: ErrorResponses[403],
					404: ErrorResponses[404]
				}
			}),
			validator(
				'json',
				z
					.object({
						agentPid: z.number().int().meta({
							description: 'The reporting agent’s own process id, in its own namespace'
						}),
						boxesKnown: z.number().int().meta({ description: 'How many boxes the host holds' }),
						boxesRunning: z.number().int().meta({
							description: 'How many of them are running'
						}),
						boxes: z.array(Box.Reported).meta({
							description: 'Every box the host holds. A full snapshot, never a delta'
						})
					})
					// Strict, so a field this cannot act on is a validation error a
					// host operator sees rather than one quietly dropped. Capacity
					// belongs here eventually and it has no honest fields yet;
					// refusing the ones nobody measures is how it stays that way.
					.strict()
			),
			async (c) => {
				const machine = await Machine.fromID(Actor.machineID);
				if (!machine) {
					// Same answer as the beat gives, for the same reason: the
					// credentials authenticated but the row is gone, and a host
					// must re-register rather than keep reporting into nothing.
					throw new VisibleError(
						'not_found',
						ErrorCodes.NotFound.RESOURCE_NOT_FOUND,
						'This machine no longer exists'
					);
				}

				const { boxes } = c.req.valid('json');
				const outcome = await Box.applyHostReport({ machineId: Actor.machineID, boxes });

				// `agentPid`, `boxesKnown` and `boxesRunning` are read and not
				// stored. They are a summary of the list that follows them, and a
				// stored copy is a second answer to a question the list already
				// answers — one that goes stale the first time the two disagree.
				// They stay on the wire because a host that cannot enumerate its
				// boxes can still say how many it has.
				if (outcome.unknown.length > 0) {
					// Loudly, per the contract this endpoint is built to: a host
					// holding boxes nobody placed there is a bug to surface, not a
					// state to reconcile quietly. Nothing is created for them.
					// eslint-disable-next-line no-console
					console.warn(
						'host report named boxes that are not placed here:',
						Actor.machineID,
						outcome.unknown.join(', ')
					);
				}

				return c.json({ data: outcome });
			}
		)
		.get(
			'/me',
			machineOnly,
			describeRoute({
				tags: ['Machine'],
				summary: 'Describe the calling machine',
				description:
					'Returns the registration record for the credentials used. A box calls this at startup to confirm its credentials still work before relying on them.',
				responses: {
					200: {
						content: { 'application/json': { schema: Result(Machine.Info) } },
						description: 'The calling machine'
					},
					403: ErrorResponses[403],
					404: ErrorResponses[404]
				}
			}),
			async (c) => {
				const machine = await Machine.fromID(Actor.machineID);
				if (!machine) {
					throw new VisibleError(
						'not_found',
						ErrorCodes.NotFound.RESOURCE_NOT_FOUND,
						'This machine no longer exists'
					);
				}
				return c.json({ data: machine });
			}
		)
		.get(
			'/',
			notPublic,
			describeRoute({
				tags: ['Machine'],
				summary: 'List your registered hosts',
				responses: {
					200: {
						content: { 'application/json': { schema: Result(z.array(Machine.Info)) } },
						description: 'Machines owned by the caller'
					},
					401: ErrorResponses[401],
					403: ErrorResponses[403]
				}
			}),
			async (c) => {
				return c.json({ data: await Machine.listByOwner(Actor.userID) });
			}
		);
}