import * as databrew from "@distilled.cloud/aws/databrew";
import * as Effect from "effect/Effect";
import * as Stream from "effect/Stream";
import { Unowned } from "../../AdoptPolicy.ts";
import { isResolved } from "../../Diff.ts";
import { createPhysicalName } from "../../PhysicalName.ts";
import * as Provider from "../../Provider.ts";
import { Resource } from "../../Resource.ts";
import { createInternalTags, hasAlchemyTags } from "../../Tags.ts";
import { AWSEnvironment } from "../Environment.ts";
import type { Providers } from "../Providers.ts";
import {
  cleanMap,
  databrewArn,
  fetchObservedTags,
  retryWhileConflict,
  retryWhileRoleNotAssumable,
  syncTags,
} from "./internal.ts";

/** How DataBrew samples the dataset in the interactive project view. */
export interface ProjectSample {
  /** Number of rows in the sample (default 500). */
  size?: number;
  /** Sampling strategy. */
  type: "FIRST_N" | "LAST_N" | "RANDOM" | (string & {});
}

export interface ProjectProps {
  /**
   * Name of the project. If omitted, a unique name is generated. Changing
   * the name replaces the project.
   * @default a generated physical name
   */
  projectName?: string;
  /**
   * The dataset the project explores. Changing it replaces the project.
   */
  datasetName: string;
  /**
   * The recipe the project edits (its `LATEST_WORKING` version). Changing
   * it replaces the project.
   */
  recipeName: string;
  /**
   * The sample shown in the interactive session.
   * @default 500 rows, FIRST_N
   */
  sample?: ProjectSample;
  /**
   * The IAM role ARN DataBrew assumes for the project's interactive
   * sessions (needs read access to the dataset's source).
   */
  role: string;
  /**
   * Tags to apply to the project. Merged with internal Alchemy tags.
   */
  tags?: Record<string, string>;
}

export interface Project extends Resource<
  "AWS.DataBrew.Project",
  ProjectProps,
  {
    /** Name of the project. */
    projectName: string;
    /** ARN of the project. */
    projectArn: string;
  },
  {},
  Providers
> {}

/**
 * An AWS Glue DataBrew project — the interactive workspace binding a dataset
 * to a recipe's working version. The project definition is free; costs only
 * accrue when an interactive session is started in the console.
 * ### Creating Projects
 * **Example:** Dataset + Recipe Project
 * ```typescript
 * import * as AWS from "alchemy/AWS";
 *
 * const project = yield* AWS.DataBrew.Project("Explore", {
 *   datasetName: dataset.datasetName,
 *   recipeName: recipe.recipeName,
 *   role: role.roleArn,
 * });
 * ```
 *
 * **Example:** Custom Sample
 * ```typescript
 * const project = yield* AWS.DataBrew.Project("Explore", {
 *   datasetName: dataset.datasetName,
 *   recipeName: recipe.recipeName,
 *   sample: { type: "RANDOM", size: 250 },
 *   role: role.roleArn,
 * });
 * ```
 *
 * @resource
 */
export const Project = Resource<Project>("AWS.DataBrew.Project");

const buildSample = (sample: ProjectSample | undefined) =>
  sample ? { Size: sample.size, Type: sample.type } : undefined;

export const ProjectProvider = () =>
  Provider.effect(
    Project,
    Effect.gen(function* () {
      const createName = Effect.fn(function* (
        id: string,
        props: { projectName?: string | undefined },
      ) {
        return (
          props.projectName ??
          (yield* createPhysicalName({ id, maxLength: 255 }))
        );
      });

      const observe = Effect.fn(function* (name: string) {
        return yield* databrew
          .describeProject({ Name: name })
          .pipe(
            Effect.catchTag("ResourceNotFoundException", () =>
              Effect.succeed(undefined),
            ),
          );
      });

      return Project.Provider.of({
        stables: ["projectName", "projectArn"],

        list: () =>
          Effect.gen(function* () {
            const { accountId, region } = yield* AWSEnvironment.current;
            const pages = yield* databrew.listProjects
              .pages({})
              .pipe(Stream.runCollect);
            return Array.from(pages)
              .flatMap((page) => page.Projects ?? [])
              .map((p) => ({
                projectName: p.Name,
                projectArn:
                  p.ResourceArn ??
                  databrewArn(region, accountId, "project", p.Name),
              }));
          }),

        read: Effect.fn(function* ({ id, olds, output }) {
          const { accountId, region } = yield* AWSEnvironment.current;
          const name =
            output?.projectName ?? (yield* createName(id, olds ?? {}));
          const project = yield* observe(name);
          if (project === undefined) return undefined;
          const arn =
            project.ResourceArn ??
            databrewArn(region, accountId, "project", name);
          const attrs = { projectName: name, projectArn: arn };
          const tags = cleanMap(project.Tags);
          return (yield* hasAlchemyTags(id, tags)) ? attrs : Unowned(attrs);
        }),

        diff: Effect.fn(function* ({ id, news, olds }) {
          if (!isResolved(news)) return undefined;
          const oldName = yield* createName(id, olds);
          const newName = yield* createName(id, news);
          if (oldName !== newName) return { action: "replace" } as const;
          // UpdateProject only accepts Sample + RoleArn — the dataset and
          // recipe associations are immutable.
          if (olds.datasetName !== news.datasetName) {
            return { action: "replace" } as const;
          }
          if (olds.recipeName !== news.recipeName) {
            return { action: "replace" } as const;
          }
        }),

        reconcile: Effect.fn(function* ({ id, news, output, session }) {
          const { accountId, region } = yield* AWSEnvironment.current;
          const name = output?.projectName ?? (yield* createName(id, news));
          const internalTags = yield* createInternalTags(id);
          const desiredTags = { ...news.tags, ...internalTags };

          // 1. OBSERVE
          const project = yield* observe(name);

          // 2. ENSURE / 3. SYNC (Sample + RoleArn are the mutable aspects)
          if (project === undefined) {
            yield* retryWhileRoleNotAssumable(
              databrew.createProject({
                Name: name,
                DatasetName: news.datasetName,
                RecipeName: news.recipeName,
                Sample: buildSample(news.sample),
                RoleArn: news.role,
                Tags: desiredTags,
              }),
            ).pipe(Effect.catchTag("ConflictException", () => Effect.void));
          } else {
            yield* retryWhileRoleNotAssumable(
              databrew.updateProject({
                Name: name,
                Sample: buildSample(news.sample),
                RoleArn: news.role,
              }),
            );
          }

          const arn =
            project?.ResourceArn ??
            databrewArn(region, accountId, "project", name);

          // 3b. SYNC TAGS against observed cloud tags
          const observedTags = yield* fetchObservedTags(arn);
          yield* syncTags(arn, observedTags, desiredTags);

          yield* session.note(name);
          return { projectName: name, projectArn: arn };
        }),

        delete: Effect.fn(function* ({ output }) {
          // ConflictException while an interactive session is winding down.
          yield* retryWhileConflict(
            databrew.deleteProject({ Name: output.projectName }),
          ).pipe(
            Effect.catchTag("ResourceNotFoundException", () =>
              Effect.succeed(undefined),
            ),
          );
        }),
      });
    }),
  );