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machine.js

// Available variables:
// - Machine
// - interpret
// - assign
// - send
// - sendParent
// - spawn
// - raise
// - actions
// - XState (all XState exports)

// this would be set based on some event data
const isDraft = (context, event) => true;

const buildStates = {
  initial: "building",
  states: {
    building: {
      on: {
        SUCCESS: "passing",
        FAILURE: "failing",
      },
    },
    failing: {
      on: {
        REBUILD: "building",
      },
    },
    passing: {
      type: "final",
    },
  },
};
const reviewStates = {
  initial: "development",
  states: {
    development: {
      on: {
        FINISHED: "review",
      },
    },
    review: {
      on: {
        REQUEST_CHANGES: "development",
        APPROVE: "passed",
      },
    },
    passed: {
      type: "final",
    },
  },
};

const prMachine = Machine({
  id: "pr",
  initial: "unknown",
  context: {
    checks: {},
  },
  states: {
    unknown: {
      on: {
        "": [
          //
          { target: "draft", cond: isDraft },
          { target: "open" },
        ],
      },
    },
    draft: {
      on: {
        OPEN: "open",
      },
    },
    open: {
      type: "parallel",
      on: {
        CLOSE: "closed",
      },
      states: {
        build: {
          ...buildStates,
          on: {
            // this acts like a reset
            BRANCH_UPDATED: "build",
          },
        }, // end build
        review: {
          ...reviewStates,
          on: {
            BRANCH_UPDATED: "review.review",
          },
        }, // end review
        // TODO do we need check for merge conflict?
      },
      onDone: "merging",
    }, // end open
    merging: {
      on: {
        MERGE_AND_CLOSE: "closed",
      },
    },
    closed: {
      on: {
        REOPEN: "open",
      },
    },
  },
});