import { Injectable } from '@nestjs/common';
import { Transactional } from '@nestjs-cls/transactional';
import { Feature } from '@prisma/client';
import { z } from 'zod';

import { BaseModel } from './base';
import {
  type FeatureConfig,
  FeatureConfigs,
  type FeatureName,
  FeaturesShapes,
  FeatureType,
} from './common';

// TODO(@forehalo):
//   `version` column in `features` table will deprecated because it's makes the whole system complicated without any benefits.
//   It was brought to introduce a version control for features, but the version controlling is not and will not actually needed.
//   It even makes things harder when a new version of an existing feature is released.
//   We have to manually update all the users and workspaces binding to the latest version, which are thousands of handreds.
//   This is a huge burden for us and we should remove it.
@Injectable()
export class FeatureModel extends BaseModel {
  async get<T extends FeatureName>(name: T) {
    const feature = await this.get_unchecked(name);

    return {
      ...feature,
      configs: this.check(name, feature.configs),
    };
  }

  /**
   * Get the latest feature from database.
   *
   * @internal
   */
  async try_get_unchecked<T extends FeatureName>(name: T) {
    const feature = await this.db.feature.findFirst({
      where: { name },
    });

    return feature as Omit<Feature, 'configs'> & {
      configs: Record<string, any>;
    };
  }

  /**
   * Get the latest feature from database.
   *
   * @throws {Error} If the feature is not found in DB.
   * @internal
   */
  async get_unchecked<T extends FeatureName>(name: T) {
    const feature = await this.try_get_unchecked(name);

    // All features are hardcoded in the codebase
    // It would be a fatal error if the feature is not found in DB.
    if (!feature) {
      throw new Error(`Feature ${name} not found`);
    }

    return feature;
  }

  check<T extends FeatureName>(name: T, config: any) {
    const shape = this.getConfigShape(name);
    const parseResult = shape.safeParse(config);

    if (!parseResult.success) {
      throw new Error(`Invalid feature config for ${name}`, {
        cause: parseResult.error,
      });
    }

    return parseResult.data as FeatureConfig<T>;
  }

  getConfigShape(name: FeatureName): z.ZodObject<any> {
    return FeaturesShapes[name] ?? z.object({});
  }

  getFeatureType(name: FeatureName): FeatureType {
    return FeatureConfigs[name].type;
  }

  @Transactional()
  private async upsert<T extends FeatureName>(
    name: T,
    configs: FeatureConfig<T>,
    deprecatedType: FeatureType,
    deprecatedVersion: number
  ) {
    const parsedConfigs = this.check(name, configs);

    // TODO(@forehalo):
    //   could be a simple upsert operation, but we got useless `version` column in the database
    //   will be fixed when `version` column gets deprecated
    const latest = await this.db.feature.findFirst({
      where: {
        name,
      },
      orderBy: {
        deprecatedVersion: 'desc',
      },
    });

    let feature: Feature;
    if (!latest) {
      feature = await this.db.feature.create({
        data: {
          name,
          deprecatedType,
          deprecatedVersion,
          configs: parsedConfigs,
        },
      });
    } else {
      feature = await this.db.feature.update({
        where: { id: latest.id },
        data: {
          configs: parsedConfigs,
        },
      });
    }

    this.logger.verbose(`Feature ${name} upserted`);

    return feature as Feature & { configs: FeatureConfig<T> };
  }

  async refreshFeatures() {
    for (const key in FeatureConfigs) {
      const name = key as FeatureName;
      const def = FeatureConfigs[name];
      // self-hosted instance will use pro plan as free plan
      if (name === 'free_plan_v1' && env.selfhosted) {
        await this.upsert(
          name,
          FeatureConfigs['pro_plan_v1'].configs,
          def.type,
          def.deprecatedVersion
        );
      } else {
        await this.upsert(name, def.configs, def.type, def.deprecatedVersion);
      }
    }
  }
}