import { Injectable } from '@nestjs/common';
import type { EntityManager } from 'typeorm';

export interface FieldDiscoveryInspectionLinkResult {
  actId: string | null;
}

@Injectable()
export class FieldDiscoveryInspectionLinkService {
  async attach(
    manager: EntityManager,
    visitId: string,
    assetId: string,
    userId: string,
  ): Promise<FieldDiscoveryInspectionLinkResult> {
    const [act] = (await manager.query(
      `
        SELECT id, status
        FROM inspection_acts
        WHERE visit_id = $1
          AND status = 'DRAFT'
        ORDER BY created_at DESC
        LIMIT 1
        FOR UPDATE
      `,
      [visitId],
    )) as Array<{ id: string; status: string }>;

    const [existing] = (await manager.query(
      `
        SELECT included, planning_source AS "planningSource"
        FROM inspection_visit_assets
        WHERE visit_id = $1 AND asset_id = $2
        FOR UPDATE
      `,
      [visitId, assetId],
    )) as Array<{ included: boolean; planningSource: string }>;

    await manager.query(
      `
        INSERT INTO inspection_visit_assets (
          visit_id, asset_id, included, planning_source, added_by,
          exclusion_reason, excluded_by, excluded_at
        )
        VALUES ($1, $2, true, 'FIELD', $3, NULL, NULL, NULL)
        ON CONFLICT (visit_id, asset_id) DO UPDATE SET
          included = true,
          planning_source = CASE
            WHEN inspection_visit_assets.planning_source IN ('AUTOMATIC','VERIFICATION')
              THEN inspection_visit_assets.planning_source
            ELSE 'FIELD'
          END,
          added_by = EXCLUDED.added_by,
          exclusion_reason = NULL,
          excluded_by = NULL,
          excluded_at = NULL,
          updated_at = CURRENT_TIMESTAMP
      `,
      [visitId, assetId, userId],
    );

    const eventType = existing && existing.included ? null : 'FIELD_INCLUDED';
    if (eventType) {
      await manager.query(
        `
          INSERT INTO inspection_visit_asset_events (
            visit_id, asset_id, event_type, actor_user_id, metadata
          )
          VALUES ($1, $2, 'FIELD_INCLUDED', $3, $4::jsonb)
        `,
        [
          visitId,
          assetId,
          userId,
          JSON.stringify({
            fieldSelection: true,
            previousPlanningSource: existing?.planningSource ?? null,
          }),
        ],
      );
    }

    if (act) {
      await manager.query(
        `
          INSERT INTO inspection_act_assets (act_id, asset_id, included, added_by)
          VALUES ($1, $2, true, $3)
          ON CONFLICT (act_id, asset_id) DO UPDATE SET
            included = true,
            added_by = EXCLUDED.added_by,
            updated_at = CURRENT_TIMESTAMP
        `,
        [act.id, assetId, userId],
      );
    }

    return { actId: act?.id ?? null };
  }
}