/*
|--------------------------------------------------------------------------
| node ace make:command fix-version-related-ids
| DONE:    create commands/fix_version_related_ids.ts
|--------------------------------------------------------------------------
| Repairs the `related_document_id` foreign key on version references
| (IsNewVersionOf / IsPreviousVersionOf, both directions).
|
| The DOI stored in `value` is the reliable link; `related_document_id`
| is frequently NULL or self-referential. This command resolves the target
| dataset via its DOI and sets `related_document_id` accordingly, correcting
| both NULL and wrong-but-non-null values.
|
| Examples:
|   node ace fix:version-related-ids                 // dry run, all datasets
|   node ace fix:version-related-ids --verbose       // dry run with per-row detail
|   node ace fix:version-related-ids --fix           // apply changes
|   node ace fix:version-related-ids --fix -p 226    // apply, only refs owned by publish_id 226
*/
import { BaseCommand, flags } from '@adonisjs/core/ace';
import type { CommandOptions } from '@adonisjs/core/types/ace';
import Dataset from '#models/dataset';
import DatasetReference from '#models/dataset_reference';

export default class FixVersionRelatedIds extends BaseCommand {
    static commandName = 'fix:version-related-ids';
    static description =
        'Backfill/repair related_document_id on IsNewVersionOf / IsPreviousVersionOf references by resolving the target dataset via its DOI';

    public static needsApplication = true;

    @flags.boolean({ alias: 'f', description: 'Apply changes. Without this flag the command runs as a dry run.' })
    public fix: boolean = false;

    @flags.boolean({ alias: 'v', description: 'Verbose output (per-reference detail)' })
    public verbose: boolean = false;

    @flags.number({ alias: 'p', description: 'Only process references owned by this publish_id' })
    public publish_id?: number;

    public static options: CommandOptions = {
        startApp: true,
        staysAlive: false,
    };

    // Only the version relations, both directions.
    private readonly VERSION_RELATIONS = ['IsNewVersionOf', 'IsPreviousVersionOf'];

    async run() {
        this.logger.info(`🔍 Scanning ${this.VERSION_RELATIONS.join(' / ')} references...`);
        this.logger.info(this.fix ? '✏️  Mode: APPLY (changes will be written)' : '👀 Mode: DRY RUN (no changes written)');
        if (typeof this.publish_id === 'number') {
            this.logger.info(`🎯 Filtering by owning publish_id: ${this.publish_id}`);
        }

        try {
            const query = DatasetReference.query()
                .whereIn('relation', this.VERSION_RELATIONS)
                .whereIn('type', ['DOI', 'URL'])
                .where((q) => {
                    q.where('value', 'like', '%doi.org/10.24341/tethys.%').orWhere('value', 'like', '%tethys.at/dataset/%');
                });

            // Restrict to references owned by a specific dataset (by publish_id), if requested.
            if (typeof this.publish_id === 'number') {
                query.whereHas('dataset', (d) => d.where('publish_id', this.publish_id as number));
            }

            const refs = await query.exec();
            this.logger.info(`🔗 Found ${refs.length} version reference(s) to inspect`);

            let alreadyCorrect = 0;
            let filledFromNull = 0;
            let correctedWrong = 0;
            let unresolved = 0;

            for (const ref of refs) {
                const target = await this.resolveTarget(ref);

                if (!target) {
                    unresolved++;
                    if (this.verbose) {
                        this.logger.warning(`⚠️  Reference ${ref.id}: could not resolve target (value: ${ref.value})`);
                    }
                    continue;
                }

                // Never let a reference point at its own owning document.
                if (target.id === ref.document_id) {
                    unresolved++;
                    if (this.verbose) {
                        this.logger.warning(
                            `⚠️  Reference ${ref.id}: target resolves to its own document (${ref.document_id}); skipping self-link`,
                        );
                    }
                    continue;
                }

                if (ref.related_document_id === target.id) {
                    alreadyCorrect++;
                    continue;
                }

                const previous = ref.related_document_id;
                const wasNull = previous === null || previous === undefined;

                if (this.fix) {
                    ref.related_document_id = target.id;
                    await ref.save();
                }

                if (wasNull) {
                    filledFromNull++;
                } else {
                    correctedWrong++;
                }

                if (this.verbose) {
                    const action = this.fix ? 'Updated' : '📝 Would update';
                    this.logger.info(
                        `${action} reference ${ref.id} (doc ${ref.document_id}, ${ref.relation}): ` +
                        `related_document_id ${previous ?? 'NULL'} → ${target.id} (publish_id ${target.publish_id})`,
                    );
                }
            }

            this.logger.info('────────────────────────────────────────');
            this.logger.info(`✔️  Already correct:       ${alreadyCorrect}`);
            this.logger.info(`➕ Filled from NULL:       ${filledFromNull}`);
            this.logger.info(`🔧 Corrected wrong value:  ${correctedWrong}`);
            this.logger.info(`⚠️  Unresolved/skipped:    ${unresolved}`);
            this.logger.info('────────────────────────────────────────');

            const changes = filledFromNull + correctedWrong;
            if (!this.fix && changes > 0) {
                this.logger.info(`💡 Dry run only. Re-run with --fix to write ${changes} change(s).`);
            } else if (this.fix) {
                this.logger.success(`Done. ${changes} reference(s) updated.`);
            } else {
                this.logger.success('Nothing to change — all version references already linked correctly.');
            }
        } catch (error) {
            this.logger.error('Error fixing version related_document_id values:', error);
            process.exit(1);
        }
    }

    /**
     * Resolve the dataset a version reference points to.
     * Prefers the DOI in `value` (reliable); falls back to a tethys publish_id URL.
     */
    private async resolveTarget(ref: DatasetReference): Promise<Dataset | null> {
        const doi = this.normalizeDoi(ref.value);
        if (doi) {
            const byDoi = await Dataset.query()
                .whereHas('identifier', (q) => q.where('value', doi))
                .first();
            if (byDoi) return byDoi;
        }

        const publishId = this.extractPublishId(ref.value);
        if (publishId) {
            const byPublishId = await Dataset.query().where('publish_id', publishId).first();
            if (byPublishId) return byPublishId;
        }

        return null;
    }

    /**
     * Strip the resolver prefix so a reference value like
     * "https://doi.org/10.24341/tethys.108.2" matches the identifier
     * table value "10.24341/tethys.108.2". Returns null if it isn't a DOI.
     */
    private normalizeDoi(value: string | null): string | null {
        if (!value) return null;
        const cleaned = value
            .trim()
            .replace(/^https?:\/\/(dx\.)?doi\.org\//i, '')
            .replace(/^doi:/i, '');
        return /^10\.\d{4,}\//.test(cleaned) ? cleaned : null;
    }

    private extractPublishId(value: string | null): number | null {
        if (!value) return null;
        const urlMatch = value.match(/tethys\.at\/dataset\/(\d+)/);
        return urlMatch ? parseInt(urlMatch[1], 10) : null;
    }
}