import moment from 'moment';
import logging from '@tryghost/logging';
import type {SchedulerAdapter, SchedulerJob} from '@tryghost/adapter-base-scheduling';
import type {InternalApiKey, InternalKeys} from '../internal-keys';

// CJS-only modules — typed loosely below. models is the Bookshelf registry
// without TS declarations; the rest are JS modules without types.
const models = require('../../models');
const urlUtils = require('../../../shared/url-utils').default;
const {getSignedAdminToken} = require('../../adapters/scheduling/utils');
const events = require('../../lib/common/events');

interface PostSchedulingDeps {
    apiUrl: string;
    // Optional in deps so the JS wrapper can pass options.schedulerAdapter
    // through without TS complaining at the JS/TS boundary. The class field
    // below is non-optional; the constructor's adapter.register(this) call
    // throws if undefined is passed through in practice.
    adapter?: SchedulerAdapter;
    internalKeys: InternalKeys;
}

// Pages live in the posts table with type:'page', so both types are
// queried through models.Post and discriminated via the type filter.
const SCHEDULED_RESOURCES = ['post', 'page'] as const;
type ScheduledResource = typeof SCHEDULED_RESOURCES[number];

export default class PostScheduling {
    readonly #apiUrl: string;
    readonly #adapter: SchedulerAdapter;
    readonly #internalKeys: InternalKeys;

    constructor({apiUrl, adapter, internalKeys}: PostSchedulingDeps) {
        this.#apiUrl = apiUrl;
        this.#adapter = adapter!;
        this.#internalKeys = internalKeys;

        SCHEDULED_RESOURCES.forEach((resource) => {
            events.on(`${resource}.scheduled`, async (model: any) => {
                try {
                    const key = await internalKeys.get('ghost-scheduler');
                    this.#adapter.schedule(this.#normalize({model, key, resourceType: resource}));
                } catch (err) {
                    logging.error({event: {name: 'post-scheduling.schedule.error'}, err, resource, id: model.get('id')}, 'Failed to schedule resource');
                }
            });

            // Reschedule = matched unschedule + fresh schedule, because tokens
            // are signed against the published_at timestamp.
            events.on(`${resource}.rescheduled`, async (model: any) => {
                try {
                    const key = await internalKeys.get('ghost-scheduler');
                    this.#adapter.unschedule(this.#normalize({model, key, resourceType: resource}, 'unscheduled'));
                    this.#adapter.schedule(this.#normalize({model, key, resourceType: resource}));
                } catch (err) {
                    logging.error({event: {name: 'post-scheduling.reschedule.error'}, err, resource, id: model.get('id')}, 'Failed to reschedule resource');
                }
            });

            events.on(`${resource}.unscheduled`, async (model: any) => {
                try {
                    const key = await internalKeys.get('ghost-scheduler');
                    this.#adapter.unschedule(this.#normalize({model, key, resourceType: resource}, 'unscheduled'));
                } catch (err) {
                    logging.error({event: {name: 'post-scheduling.unschedule.error'}, err, resource, id: model.get('id')}, 'Failed to unschedule resource');
                }
            });
        });

        this.#adapter.register(this);
    }

    /**
     * Re-issue every queued schedule under the current internal-keys cache.
     * On boot the previous key is the same as the current key. For key
     * rotation, the caller passes `previousKey` so unschedule URLs match
     * the entries the adapter already holds (signed under the previous
     * secret); schedule URLs are reissued under the current secret.
     */
    async rescheduleAll({previousKey}: {previousKey?: InternalApiKey} = {}): Promise<void> {
        const scheduledResources = await this.#loadScheduledResources();
        const currentKey = await this.#internalKeys.get('ghost-scheduler');
        const unscheduleKey = previousKey ?? currentKey;

        // Same-key rebuild (no previousKey, boot path) → URL signature is
        // identical to the about-to-be-scheduled job. The default adapter
        // implements unschedule via tombstones keyed by URL+time, so a same-URL
        // unschedule poisons the scheduled job. Bootstrap mode skips the
        // tombstone write. Rotation (previousKey provided) → URLs differ, so
        // the tombstone correctly targets the old queued entry.
        const bootstrap = !previousKey;

        for (const resourceType of Object.keys(scheduledResources) as ScheduledResource[]) {
            for (const model of scheduledResources[resourceType]) {
                this.#adapter.unschedule(
                    this.#normalize({model, key: unscheduleKey, resourceType}),
                    {bootstrap}
                );
                this.#adapter.schedule(
                    this.#normalize({model, key: currentKey, resourceType})
                );
            }
        }
    }

    async #loadScheduledResources(): Promise<Record<ScheduledResource, any[]>> {
        const entries = await Promise.all(SCHEDULED_RESOURCES.map(async (resourceType) => {
            const found = await models.Post.findAll({
                filter: `status:scheduled+type:${resourceType}`,
                columns: ['id', 'published_at', 'created_at', 'type']
            });
            return [resourceType, found];
        }));
        return Object.fromEntries(entries);
    }

    #normalize({model, resourceType, key}: {model: any; resourceType: ScheduledResource; key: InternalApiKey}, event: '' | 'unscheduled' = ''): SchedulerJob {
        const resource = `${resourceType}s`;
        const publishedAt = (event === 'unscheduled') ? model.previous('published_at') : model.get('published_at');
        const signedAdminToken = getSignedAdminToken({publishedAt, apiUrl: this.#apiUrl, key});
        const url = `${urlUtils.urlJoin(this.#apiUrl, 'schedules', resource, model.get('id'))}/?token=${signedAdminToken}`;

        return {
            // NOTE: The scheduler expects a unix timestamp.
            time: moment(publishedAt).valueOf(),
            url,
            extra: {
                httpMethod: 'PUT',
                oldTime: model.previous('published_at') ? moment(model.previous('published_at')).valueOf() : null
            }
        };
    }
}
