sjansen/mecha

package scriptset

import (
    "fmt"

    "go.starlark.net/starlark"
)

type script struct {
    Concurrent bool   `json:"concurrent"`
    Steps      []*cmd `json:"steps"`
}

func (s *script) init(
    steps starlark.Value,
) error {
    switch x := steps.(type) {
    case *cmd:
        s.Concurrent = false
        s.Steps = []*cmd{x}
    case *starlark.List:
        s.Concurrent = false
        if err := s.initSteps(x.Len(), x); err != nil {
            return err
        }
    case *starlark.Set:
        s.Concurrent = true
        if err := s.initSteps(x.Len(), x); err != nil {
            return err
        }
    default:
        return fmt.Errorf(
            "script: got %s, want cmd, list of cmd, or set of cmd", steps.Type(),
        )
    }

    return nil
}

func (s *script) initSteps(n int, x starlark.Iterable) error {
    s.Steps = make([]*cmd, 0, n)

    iter := x.Iterate()
    defer iter.Done()

    var item starlark.Value
    for iter.Next(&item) {
        if cmd, ok := item.(*cmd); ok {
            s.Steps = append(s.Steps, cmd)
        } else {
            return fmt.Errorf(
                "script: got %s, want cmd", x.Type(),
            )
        }
    }

    return nil
}