servitor/common/src/main/kotlin/wf/servitor/common/workflow/Step.kt

package wf.servitor.common.workflow

import com.fasterxml.jackson.databind.annotation.JsonDeserialize
import com.fasterxml.jackson.databind.annotation.JsonPOJOBuilder
import wf.servitor.common.workflow.step.*
import java.io.Serializable

@Suppress("unused")
@JsonDeserialize(builder = Step.Builder::class)
interface Step : Serializable {
    val name: String

    fun getChild(index: Int): Step? {
        return null
    }

    fun children() = 0
    fun getScript(): String? = null
    fun next(result: Any?): StepContinuation = StepContinuation.Continue

    @JsonPOJOBuilder(buildMethodName = "build", withPrefix = "with")
    class Builder {
        var name: String = ""
        var `if`: String? = null
        var `do`: String? = null
        var then: String? = null
        var `else`: String? = null
        var options: List<OptionsStep.Option>? = null
        var collect: List<Step>? = null

        fun withName(value: String) {
            this.name = value
        }

        fun withIf(value: String) {
            this.`if` = value
        }

        fun withDo(value: String) {
            this.`do` = value
        }

        fun withThen(value: String) {
            this.then = value
        }

        fun withElse(value: String) {
            this.`else` = value
        }

        fun withOptions(value: List<OptionsStep.Option>) {
            this.options = value
        }

        fun withCollect(value: List<Step>) {
            this.collect = value
        }

        fun build(): Step {
            val `if` = this.`if`
            val `do` = this.`do`

            if (`if` != null) {
                if (`do` != null) {
                    return IfActionStep(`if`, `do`, name)
                }

                val then = then
                val `else` = `else`

                if (then != null || `else` != null) {
                    return IfJumpStep(`if`, then, `else`, name)
                }

                error("Step missing 'then', 'else' or 'do'")
            }

            val options = options
            if (options != null) {
                return OptionsStep(options, name)
            }

            val collect = collect
            if (collect != null) {
                return CollectStep(collect, name)
            }

            if (`do` != null) {
                return ActionStep(`do`, name)
            }

            error("No matching type of step could be found")
        }
    }
}