import * as Array from "effect/Array";
import * as Config from "effect/Config";
import * as Effect from "effect/Effect";
import { flow } from "effect/Function";
import * as Option from "effect/Option";
import * as String from "effect/String";

export interface GitHubEnv {
  /** The commit SHA that triggered the workflow run. */
  readonly sha: string;
  /** The repository owner from `GITHUB_REPOSITORY_OWNER`. */
  readonly owner: string;
  /** The repository name parsed from `GITHUB_REPOSITORY`. */
  readonly repository: string;
  /** The pull request number exported by the Alchemy GitHub Action. */
  readonly pr: number | undefined;
}

/**
 * GitHub Actions metadata for conditional resources in `alchemy.run.ts`.
 *
 * Resolves to `undefined` outside GitHub Actions. In GitHub Actions, it reads
 * `GITHUB_SHA`, `GITHUB_REPOSITORY_OWNER`, `GITHUB_REPOSITORY`, and the optional
 * `PULL_REQUEST` variable exported by the Alchemy GitHub Action.
 */
export const GitHubEnv: Config.Config<GitHubEnv | undefined> = Config.boolean(
  "GITHUB_ACTIONS",
).pipe(
  Config.withDefault(false),
  // Config has no flatMap in Effect 4; a Config is itself an Effect, so the
  // enabled branch returns the inner config for mapOrFail to evaluate.
  Config.mapOrFail(
    (enabled): Effect.Effect<GitHubEnv | undefined, Config.ConfigError> =>
      enabled
        ? Config.all({
            sha: Config.string("GITHUB_SHA"),
            owner: Config.string("GITHUB_REPOSITORY_OWNER"),
            repository: Config.string("GITHUB_REPOSITORY").pipe(
              Config.mapOrFail(
                flow(
                  String.split("/"),
                  Array.get(1),
                  Effect.fromOption,
                  Effect.catchTags({
                    NoSuchElementError: Effect.die,
                  }),
                ),
              ),
            ),
            pr: Config.number("PULL_REQUEST").pipe(
              Config.option,
              Config.map(Option.getOrUndefined),
            ),
          })
        : Effect.succeed(undefined),
  ),
);