import { makeNixCommandArgs } from "./nix.js";
import * as actionsCore from "@actions/core";
import * as actionsExec from "@actions/exec";
import { DetSysAction, inputs } from "detsys-ts";

const EVENT_EXECUTION_FAILURE = "execution_failure";

class UpdateFlakeLockAction extends DetSysAction {
  private commitMessage: string;
  private nixOptions: string[];
  private flakeInputs: string[];
  private pathToFlakeDir: string | null;
  private flakeDirs: string[] | null;

  constructor() {
    super({
      name: "update-flake-lock",
      fetchStyle: "universal",
      requireNix: "fail",
    });

    this.commitMessage = inputs.getString("commit-msg");
    this.flakeInputs = inputs.getArrayOfStrings("inputs", "space");
    this.nixOptions = inputs.getArrayOfStrings("nix-options", "space");
    this.pathToFlakeDir = inputs.getStringOrNull("path-to-flake-dir");
    this.flakeDirs = inputs.getArrayOfStrings("flake-dirs", "space");

    // Ensure that either path-to-flake-dir or flake-dirs is set to a meaningful value but not both
    if (
      this.flakeDirs !== null &&
      this.flakeDirs.length > 0 &&
      this.pathToFlakeDir !== ""
    ) {
      // TODO: improve this error message
      throw new Error("Both path-to-flake-dir and flake-dirs is defined");
    }
  }

  async main(): Promise<void> {
    await this.update();
  }

  // No post phase
  async post(): Promise<void> {}

  async update(): Promise<void> {
    if (this.flakeDirs !== null && this.flakeDirs.length > 0) {
      actionsCore.debug(
        `Running flake lock update in multiple directories: ${this.flakeDirs}`,
      );

      for (const directory of this.flakeDirs) {
        await this.updateFlake(directory);
      }
    } else {
      // Set directory to root if not specified
      const flakeDir = this.pathToFlakeDir ?? ".";
      await this.updateFlake(flakeDir);
    }
  }

  private async updateFlake(flakeDir: string): Promise<void> {
    actionsCore.debug(`Running flake lock update in directory ${flakeDir}`);

    // Nix command of this form:
    // nix ${maybe nix options} flake ${"update" or "lock"} ${maybe --update-input flags} --commit-lock-file --commit-lockfile-summary ${commit message}
    // Example commands:
    // nix --extra-substituters https://example.com flake lock --update-input nixpkgs --commit-lock-file --commit-lockfile-summary "updated flake.lock"
    // nix flake update --commit-lock-file --commit-lockfile-summary "updated flake.lock"
    const nixCommandArgs: string[] = makeNixCommandArgs(
      this.nixOptions,
      this.flakeInputs,
      this.commitMessage,
    );

    actionsCore.debug(
      JSON.stringify({
        directory: flakeDir,
        options: this.nixOptions,
        inputs: this.flakeInputs,
        message: this.commitMessage,
        args: nixCommandArgs,
      }),
    );

    const execOptions: actionsExec.ExecOptions = {
      cwd: flakeDir,
    };

    const exitCode = await actionsExec.exec("nix", nixCommandArgs, execOptions);

    if (exitCode !== 0) {
      this.recordEvent(EVENT_EXECUTION_FAILURE, {
        exitCode,
      });
      actionsCore.setFailed(
        `non-zero exit code of ${exitCode} detected while updating directory ${flakeDir}`,
      );
    } else {
      actionsCore.info(
        `flake.lock file in ${flakeDir} was successfully updated`,
      );
    }
  }
}

function main(): void {
  new UpdateFlakeLockAction().execute();
}

main();