modeling-app/src/machines/systemIO/systemIOMachine.ts

import { DEFAULT_PROJECT_NAME } from '@src/lib/constants'
import type { Project } from '@src/lib/project'
import type { SystemIOContext } from '@src/machines/systemIO/utils'
import {
  NO_PROJECT_DIRECTORY,
  SystemIOMachineActions,
  SystemIOMachineActors,
  SystemIOMachineEvents,
  SystemIOMachineStates,
} from '@src/machines/systemIO/utils'
import { assertEvent, assign, fromPromise, setup } from 'xstate'

/**
 * Handles any system level I/O for folders and files
 * This machine will be initializes once within the applications runtime
 * and exist for the entire life cycle of the application and able to be access
 * at a global level.
 */
export const systemIOMachine = setup({
  types: {
    context: {} as SystemIOContext,
    events: {} as
      | {
          type: SystemIOMachineEvents.readFoldersFromProjectDirectory
          data: {}
        }
      | {
          type: SystemIOMachineEvents.done_readFoldersFromProjectDirectory
          data: {}
          output: Project[]
        }
      | {
          type: SystemIOMachineEvents.setProjectDirectoryPath
          data: { requestedProjectDirectoryPath: string }
        }
      | {
          type: SystemIOMachineEvents.navigateToProject
          data: { requestedProjectName: string }
      }
      | {
          type: SystemIOMachineEvents.navigateToFile
        data: { requestedProjectName: string, requestedFileName: string }
        }
  },
  actions: {
    [SystemIOMachineActions.setFolders]: assign({
      folders: ({ event }) => {
        assertEvent(
          event,
          SystemIOMachineEvents.done_readFoldersFromProjectDirectory
        )
        return event.output
      },
    }),
    [SystemIOMachineActions.setProjectDirectoryPath]: assign({
      projectDirectoryPath: ({ event }) => {
        assertEvent(event, SystemIOMachineEvents.setProjectDirectoryPath)
        return event.data.requestedProjectDirectoryPath
      },
    }),
    [SystemIOMachineActions.setRequestedProjectName]: assign({
      requestedProjectName: ({ event }) => {
        assertEvent(event, SystemIOMachineEvents.navigateToProject)
        return { name: event.data.requestedProjectName }
      },
    }),
    [SystemIOMachineActions.setRequestedFileName]: assign({
      requestedFileName: ({ event }) => {
        assertEvent(event, SystemIOMachineEvents.navigateToFile)
        return { project: event.data.requestedProjectName, file: event.data.requestedFileName }
      },
    }),
  },
  actors: {
    [SystemIOMachineActors.readFoldersFromProjectDirectory]: fromPromise(
      async ({ input: context }: { input: SystemIOContext }) => {
        return []
      }
    ),
  },
}).createMachine({
  initial: SystemIOMachineStates.idle,
  // Remember, this machine and change its projectDirectory at any point
  // '' will be no project directory, aka clear this machine out!
  // To be the aboslute root of someones computer we should take the string of path.resolve() in node.js which is different for each OS
  context: () => ({
    folders: [],
    defaultProjectFolderName: DEFAULT_PROJECT_NAME,
    projectDirectoryPath: NO_PROJECT_DIRECTORY,
    hasListedProjects: false,
    requestedProjectName: { name: NO_PROJECT_DIRECTORY },
    requestedFileName: { name: NO_PROJECT_DIRECTORY },
  }),
  states: {
    [SystemIOMachineStates.idle]: {
      on: {
        // on can be an action
        [SystemIOMachineEvents.readFoldersFromProjectDirectory]:
        SystemIOMachineStates.readingFolders,
        [SystemIOMachineEvents.setProjectDirectoryPath]: {
          target: SystemIOMachineStates.readingFolders,
          actions: [SystemIOMachineActions.setProjectDirectoryPath],
        },
        [SystemIOMachineEvents.navigateToProject]: {
          actions: [SystemIOMachineActions.setRequestedProjectName],
        },
        [SystemIOMachineEvents.navigateToFile]: {
          actions: [SystemIOMachineActions.setRequestedFileName],
        },
      },
    },
    [SystemIOMachineStates.readingFolders]: {
      invoke: {
        id: SystemIOMachineActors.readFoldersFromProjectDirectory,
        src: SystemIOMachineActors.readFoldersFromProjectDirectory,
        input: ({ context }) => {
          return context
        },
        onDone: {
          target: SystemIOMachineStates.idle,
          actions: [SystemIOMachineActions.setFolders],
        },
        onError: {
          target: SystemIOMachineStates.idle,
        },
      },
    },
  },
})

// Watcher handler
// look at projectDirectory useEffect then send this event if it changes or if we need to do this?
// The handler needs to live somewhere... aka the provider?