// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.

// The resource package handles CRUD operations on resources and YAML (de)serialization
package resource

import (
	_ "encoding/json"
	_ "fmt"
	_ "gopkg.in/yaml.v3"
	"gitea.rosskeen.house/rosskeen.house/machine"
	"decl/internal/data"
	"errors"
)


var (
	ErrInvalidResourceURI error = errors.New("Invalid resource URI")
	ErrResourceStateAbsent = errors.New("Resource state absent")
	ErrUnableToFindResource = errors.New("Unable to find resource - not loaded")
)

type ResourceReference string

func NewResource(uri string) data.Resource {
	r, e := ResourceTypes.New(uri)
	if e == nil {
		return r
	}
	return nil
}

func ResourceConstructor(res data.Resource, uri data.URIParser) (err error) {
	if uri != nil {
		return uri.ConstructResource(res)
	} else {
		if ri, ok := res.(data.ResourceInitializer); ok {
			return ri.Init(uri)
		}
	}
	return
}

// Common resource states
func ResourceMachine(sub machine.Subscriber) machine.Stater {
	stater := machine.New("unknown")
	stater.AddStates("unkonwn", "inconsistent", "absent", "start_create", "present", "start_delete", "start_read", "start_update", "start_stat", "created")

	stater.AddTransition("create", machine.States("unknown", "inconsistent", "absent"), "start_create")
	if e := stater.AddSubscription("create", sub); e != nil {
		return nil
	}

	stater.AddTransition("created", machine.States("start_create"), "present")
	if e := stater.AddSubscription("created", sub); e != nil {
		return nil
	}

	stater.AddTransition("exists", machine.States("unknown", "inconsistent", "absent", "start_stat"), "present")
	if e := stater.AddSubscription("exists", sub); e != nil {
		return nil
	}

	stater.AddTransition("notexists", machine.States("*"), "absent")
	if e := stater.AddSubscription("notexists", sub); e != nil {
		return nil
	}

	stater.AddTransition("update-failed", machine.States("start_update"), "inconsistent")
	if e := stater.AddSubscription("update-failed", sub); e != nil {
		return nil
	}
	
	stater.AddTransition("create-failed", machine.States("start_create"), "inconsistent")
	if e := stater.AddSubscription("create-failed", sub); e != nil {
		return nil
	}

	return stater
}

func StorageMachine(sub machine.Subscriber) machine.Stater {
// start_destroy -> absent -> start_create -> present -> start_destroy

	stater := ResourceMachine(sub)

	stater.AddTransition("read", machine.States("*"), "start_read")
	if e := stater.AddSubscription("read", sub); e != nil {
		return nil
	}

	stater.AddTransition("state_read", machine.States("start_read"), "present")

	stater.AddTransition("stat", machine.States("*"), "start_stat")
	if e := stater.AddSubscription("stat", sub); e != nil {
		return nil
	}

	stater.AddTransition("update", machine.States("*"), "start_update")
	if e := stater.AddSubscription("update", sub); e != nil {
		return nil
	}

	stater.AddTransition("updated", machine.States("start_update"), "present")

	stater.AddTransition("delete", machine.States("*"), "start_delete")
	if e := stater.AddSubscription("delete", sub); e != nil {
		return nil
	}

	stater.AddTransition("deleted", machine.States("start_delete"), "absent")
	if e := stater.AddSubscription("deleted", sub); e != nil {
		return nil
	}

	return stater
}

func ProcessMachine(sub machine.Subscriber) machine.Stater {
// "enum": [ "created", "restarting", "running", "paused", "exited", "dead" ]

	stater := ResourceMachine(sub)

	stater.AddStates("restarting", "running", "paused", "exited", "dead")


	stater.AddTransition("read", machine.States("*"), "start_read")
	if e := stater.AddSubscription("read", sub); e != nil {
		return nil
	}
	stater.AddTransition("state_read", machine.States("start_read"), "present")
	stater.AddTransition("update", machine.States("*"), "start_update")
	if e := stater.AddSubscription("update", sub); e != nil {
		return nil
	}

	stater.AddTransition("stat", machine.States("*"), "start_stat")
	if e := stater.AddSubscription("stat", sub); e != nil {
		return nil
	}

	stater.AddTransition("updated", machine.States("start_update"), "present")
	stater.AddTransition("delete", machine.States("*"), "start_delete")
	if e := stater.AddSubscription("delete", sub); e != nil {
		return nil
	}
	stater.AddTransition("deleted", machine.States("start_delete"), "absent")
	if e := stater.AddSubscription("deleted", sub); e != nil {
		return nil
	}
	return stater
}