package budget

import (
	"os"

	"github.com/godbus/dbus/v5"
)

type fakeCtl struct {
	units    []unit
	groups   map[string]string
	states   map[string]unitState
	sets     map[string][]property
	starts   map[string][]property
	stops    []string
	stateErr map[string]error
	startErr error
	setErr   error
	events   *[]string
	onStart  func(string, []property)
}

func newFake() *fakeCtl {
	return &fakeCtl{groups: map[string]string{}, states: map[string]unitState{}, sets: map[string][]property{}, starts: map[string][]property{}, stateErr: map[string]error{}}
}

func (f *fakeCtl) Units() ([]unit, error)            { return f.units, nil }
func (f *fakeCtl) Group(name string) (string, error) { return f.groups[name], nil }
func (f *fakeCtl) Set(name string, props []property) error {
	if f.events != nil {
		*f.events = append(*f.events, "set "+name)
	}
	f.sets[name] = props
	return f.setErr
}
func (f *fakeCtl) Start(name string, props []property) error {
	if f.startErr != nil {
		return f.startErr
	}
	f.starts[name] = props
	f.states[name] = unitState{Active: "activating"}
	if f.onStart != nil {
		f.onStart(name, props)
	}
	return nil
}
func (f *fakeCtl) State(name string) (unitState, error) {
	if err := f.stateErr[name]; err != nil {
		return unitState{}, err
	}
	if state, ok := f.states[name]; ok {
		return state, nil
	}
	return unitState{}, dbus.Error{Name: noUnit}
}
func (f *fakeCtl) Stop(name string) error { f.stops = append(f.stops, name); return nil }

type fakeProcs struct {
	tasks  map[uint32]task
	groups map[uint32]string
}

type failWriter struct {
	err error
}

func (w failWriter) Write([]byte) (int, error) { return 0, w.err }

func (f fakeProcs) Snapshot(config) (map[uint32]task, error) { return f.tasks, nil }
func (f fakeProcs) Group(pid uint32) (string, error) {
	if group, ok := f.groups[pid]; ok {
		return group, nil
	}
	return "", os.ErrNotExist
}