package osbuild2

import (

	"encoding/json"

	"fmt"

)

// Single stage of a pipeline executing one step

type Stage struct {

	// Well-known name in reverse domain-name notation, uniquely identifying

	// the stage type.

	Type string `json:"type"`

	// Stage-type specific options fully determining the operations of the

	Inputs  Inputs       `json:"inputs,omitempty"`

	Options StageOptions `json:"options,omitempty"`

}

// Collection of Inputs for a Stage

type Inputs interface {

	isStageInputs()

}

// Single Input for a Stage

type Input interface {

	isInput()

}

// Fields shared between all Input types (should be embedded in each instance)

type inputCommon struct {

	Type string `json:"type"`

	// Origin should be either 'org.osbuild.source' or 'org.osbuild.pipeline'

	Origin string `json:"origin"`

	// References References `json:"references"`

}

type StageInput interface {

	isStageInput()

}

type References interface {

	isReferences()

}

// StageOptions specify the operations of a given stage-type.

type StageOptions interface {

	isStageOptions()

}

type InputOptions interface {

}

type rawStage struct {

	Type    string          `json:"type"`

	Options json.RawMessage `json:"options"`

	Inputs  json.RawMessage `json:"inputs"`

}

// UnmarshalJSON unmarshals JSON into a Stage object. Each type of stage has

// a custom unmarshaller for its options, selected based on the stage name.

func (stage *Stage) UnmarshalJSON(data []byte) error {

	var rawStage rawStage

	if err := json.Unmarshal(data, &rawStage); err != nil {

		return err

	}

	var options StageOptions

	var inputs Inputs

	switch rawStage.Type {

	case "org.osbuild.fix-bls":

		options = new(FixBLSStageOptions)

	case "org.osbuild.fstab":

		options = new(FSTabStageOptions)

	case "org.osbuild.grub2":

		options = new(GRUB2StageOptions)

	case "org.osbuild.locale":

		options = new(LocaleStageOptions)

	case "org.osbuild.selinux":

		options = new(SELinuxStageOptions)

	case "org.osbuild.hostname":

		options = new(HostnameStageOptions)

	case "org.osbuild.users":

		options = new(UsersStageOptions)

	case "org.osbuild.groups":

		options = new(GroupsStageOptions)

	case "org.osbuild.timezone":

		options = new(TimezoneStageOptions)

	case "org.osbuild.chrony":

		options = new(ChronyStageOptions)

	case "org.osbuild.keymap":

		options = new(KeymapStageOptions)

	case "org.osbuild.firewall":

		options = new(FirewallStageOptions)

	case "org.osbuild.rhsm":

		options = new(RHSMStageOptions)

	case "org.osbuild.systemd":

		options = new(SystemdStageOptions)

	case "org.osbuild.script":

		options = new(ScriptStageOptions)

	case "org.osbuild.sysconfig":

		options = new(SysconfigStageOptions)

	case "org.osbuild.kernel-cmdline":

		options = new(KernelCmdlineStageOptions)

	case "org.osbuild.rpm":

		options = new(RPMStageOptions)

		inputs = new(RPMStageInputs)

	case "org.osbuild.oci-archive":

		options = new(OCIArchiveStageOptions)

		inputs = new(OCIArchiveStageInputs)

	case "org.osbuild.ostree.commit":

		options = new(OSTreeCommitStageOptions)

		inputs = new(OSTreeCommitStageInputs)

	case "org.osbuild.ostree.pull":

		options = new(OSTreePullStageOptions)

		inputs = new(OSTreePullStageInputs)

	case "org.osbuild.ostree.init":

		options = new(OSTreeInitStageOptions)

	case "org.osbuild.ostree.preptree":

		options = new(OSTreePrepTreeStageOptions)

	default:

		return fmt.Errorf("unexpected stage type: %s", rawStage.Type)

	}

	if err := json.Unmarshal(rawStage.Options, options); err != nil {

		return err

	}

	if inputs != nil && rawStage.Inputs != nil {

		if err := json.Unmarshal(rawStage.Inputs, inputs); err != nil {

			return err

		}

	}

	stage.Type = rawStage.Type

	stage.Options = options

	stage.Inputs = inputs

	return nil

}