//TODO the algorithms part could be more efficient, but I don't really care
func analogies(d dynamics.Dwimmer, s *term.Setting, n int) ([]*term.Setting, []float32) {
	if s.Size == 1 {
		return contenders(d, s.Last, n)
	}

	previousSetting := s.Previous
	lastLine := s.Last
	previousAnalogies, previousPriorities := analogies(d, previousSetting, n+1)

	possibilities, possiblePriorities := []*term.Setting{}, new(indexHeap)
	i := 0
	for j, priority := range previousPriorities {
		analogy := previousAnalogies[j]
		for _, setting := range d.Continuations(analogy) {
			fit, canMatch := match(setting.Last, lastLine)
			if canMatch {
				possiblePriorities.Push(prioritized{
					index:    i,
					priority: priority * fit,
				})
				i++
				possibilities = append(possibilities, setting)
			}
		}
	}
	heap.Init(possiblePriorities)
	result := make([]*term.Setting, 0)
	priorities := make([]float32, 0)
	for i := 0; i < n && possiblePriorities.Len() > 0; i++ {
		next := heap.Pop(possiblePriorities).(prioritized)
		priorities = append(priorities, next.priority)
		result = append(result, possibilities[next.index])
	}
	return result, priorities
}

func getInput(d dynamics.Dwimmer, context *term.SettingT, hintstrings, toolmap term.T) term.T {
	quotedHints, err := represent.ToList(d, hintstrings)
	if err != nil {
		return represent.ConversionError.T(hintstrings, err)
	}
	hints := make([]string, len(quotedHints))
	for i, quoted := range quotedHints {
		hints[i], err = represent.ToStr(d, quoted)
		if err != nil {
			return represent.ConversionError.T(quoted, err)
		}
	}
	tools := make(map[rune]string)
	for toolmap.Head() != maps.Empty {
		switch toolmap.Head() {
		case maps.Cons:
			vs := toolmap.Values()
			c, err := represent.ToRune(d, vs[0])
			if err != nil {
				return represent.ConversionError.T(vs[0], err)
			}
			s, err := represent.ToStr(d, vs[1])
			if err != nil {
				return represent.ConversionError.T(vs[1], err)
			}
			tools[c] = s
			toolmap = vs[2]
		default:
			context.AppendTerm(UnrecognizedDictionary.T())
			return nil
		}
	}
	input := d.Readln(" < ", hints, tools)
	return core.Answer.T(represent.Str(input))
}

func run(d dynamics.Dwimmer, s *term.SettingT, quotedSetting term.T) term.T {
	setting, err := represent.ToSettingT(d, quotedSetting)
	if err != nil {
		return represent.ConversionError.T(quotedSetting, err)
	}
	result := d.Run(setting)
	if result == nil {
		return NoOutput.T(represent.SettingT(setting))
	}
	return Result.T(represent.T(result), represent.SettingT(setting))
}

func getTransition(d dynamics.Dwimmer, s *term.SettingT, quotedSetting term.T) term.T {
	setting, err := represent.ToSetting(d, quotedSetting)
	if err != nil {
		return term.Make("asked to get a transition in setting [], "+
			"but while converting to a setting received []").T(quotedSetting, err)
	}
	result, ok := d.Get(setting)
	if !ok {
		return NoCompiledAction.T()
	}
	return core.Answer.T(represent.Transition(result))
}

func fallThrough(d dynamics.Dwimmer, s *term.SettingT, quotedSetting term.T) term.T {
	settingT, err := represent.ToSettingT(d, quotedSetting)
	if err != nil {
		return term.Make("asked to decide what to do in setting [], "+
			"but while converting to a setting received []").T(quotedSetting, err)
	}
	transition := ElicitAction(d, s, settingT.Setting)
	if shouldSave(transition) {
		d.Save(settingT.Setting, transition)
	}
	return TakeTransition.T(represent.Transition(transition))
}

func allSettings(d dynamics.Dwimmer, s *term.SettingT) term.T {
	queue := []*term.Setting{term.Init()}
	for k := 0; k < len(queue); k++ {
		top := queue[k]
		queue = append(queue, d.Continuations(top)...)
	}
	result := make([]term.T, len(queue))
	for i, setting := range queue {
		result[i] = represent.Setting(setting)
	}
	return core.Answer.T(represent.List(result))
}

func getContinuations(d dynamics.Dwimmer, s *term.SettingT, quotedSetting term.T) term.T {
	setting, err := represent.ToSetting(d, quotedSetting)
	if err != nil {
		return term.Make("asked to return the continuations from a setting, " +
			"but while converting to a setting received []").T(err)
	}
	continuations := d.Continuations(setting)
	result := make([]term.T, len(continuations))
	for i, c := range continuations {
		result[i] = represent.Setting(c)
	}
	return core.Answer.T(represent.List(result))
}

func findAction(d dynamics.Dwimmer, s *term.SettingT, quotedSetting term.T) term.T {
	setting, err := represent.ToSetting(d, quotedSetting)
	if err != nil {
		return term.Make("asked to decide what to do in setting [], "+
			"but while converting to a setting received []").T(quotedSetting, err)
	}
	transition, ok := d.Get(setting)
	if !ok {
		transition := ElicitAction(d, s, setting)
		d.Save(setting, transition)
	}
	return core.Answer.T(represent.Transition(transition))
}

func nativeSetCursor(d dynamics.Dwimmer, s *term.SettingT, xt, yt term.T) term.T {
	x, err := represent.ToInt(d, xt)
	if err != nil {
		return term.Make("asked to move cursor, but received [] "+
			"while converting coordinate [] to an integer").T(err, xt)
	}
	y, err := represent.ToInt(d, yt)
	if err != nil {
		return term.Make("asked to move cursor, but received [] "+
			"while converting coordinate [] to an integer").T(err, yt)
	}
	d.SetCursor(x, y)
	return core.OK.T()
}

func setTransition(d dynamics.Dwimmer, s *term.SettingT, quotedTransition, quotedSetting term.T) term.T {
	transition, err := represent.ToTransition(d, quotedTransition)
	if err != nil {
		return term.Make("asked to set a setting to transition [], "+
			"but while converting to a transition received []").T(quotedTransition, err)
	}
	setting, err := represent.ToSetting(d, quotedSetting)
	if err != nil {
		return term.Make("asked to set a transition in setting [], "+
			"but while converting to a setting received []").T(quotedSetting, err)
	}
	d.Save(setting, transition)
	return core.OK.T()
}

func displayTemplate(d dynamics.Dwimmer, context *term.SettingT, quotedSetting term.T) term.T {
	setting, err := represent.ToSetting(d, quotedSetting)
	if err != nil {
		return represent.ConversionError.T(quotedSetting, err)
	}
	settingS := addNames(setting)
	ShowSettingS(d, settingS)
	d.Println("")
	d.Println("")
	quotedNames := make([]term.T, len(settingS.Names))
	for i, name := range settingS.Names {
		quotedNames[i] = represent.Str(name)
	}
	return Names.T(represent.List(quotedNames))
}

func nativePutChar(d dynamics.Dwimmer, s *term.SettingT, char, xt, yt term.T) term.T {
	c, err := represent.ToRune(d, char)
	if err != nil {
		return term.Make("asked to write character, but received [] " +
			"while converting to a character").T(err)
	}
	x, err := represent.ToInt(d, xt)
	if err != nil {
		return term.Make("asked to write character, but received [] "+
			"while converting coordinate [] to an integer").T(err, xt)
	}
	y, err := represent.ToInt(d, yt)
	if err != nil {
		return term.Make("asked to write character, but received [] "+
			"while converting coordinate [] to an integer").T(err, yt)
	}
	d.SetCursor(x, y)
	d.PrintCh(c)
	return core.OK.T()
}

func Suggestions(d dynamics.Dwimmer, s *term.Setting, n int) ([]term.ActionC, []float32) {
	settings, settingPriorities := analogies(d, s, n)
	result := []term.ActionC{}
	priorities := []float32{}
buildingResult:
	for i, other := range settings {
		t, _ := d.Get(other)
		simple, isSimple := t.(dynamics.SimpleTransition)
		if isSimple {
			action := simple.Action
			for _, otherAction := range result {
				if action.ID() == otherAction.ID() {
					continue buildingResult
				}
			}
			result = append(result, action)
			priorities = append(priorities, settingPriorities[i])
		}
	}
	return result, priorities
}

func ElicitAction(d dynamics.Dwimmer, context *term.SettingT, setting *term.Setting) dynamics.Transition {
	for {
		Q := FallThrough.T(represent.Setting(setting))
		result := dynamics.SubRun(d, Q, context)
		switch result.Head() {
		case TakeTransition:
			transition, err := represent.ToTransition(d, result.Values()[0])
			if err == nil {
				return transition
			}
		case core.OK:
		default:
			result, err := d.Answer(TransitionGiven.T(result, Q))
			if err == nil {
				transition, err := represent.ToTransition(d, result)
				if err == nil {
					return transition
				}
			}
		}
	}
}

//TODO only do this sometimes, or control better the length, or something...
func GetHints(d dynamics.Dwimmer, context *term.SettingT, s *term.SettingS, n int) []string {
	suggestions, err := d.Answer(similarity.SuggestedActions.T(
		represent.Setting(s.Setting),
		represent.Int(n),
	), context)
	if err != nil {
		return []string{}
	}
	suggestionList, err := represent.ToList(d, suggestions)
	if err != nil {
		return []string{}
	}
	result := []string{}
	for _, suggestion := range suggestionList {
		actionC, err := represent.ToActionC(d, suggestion)
		if err != nil {
			continue
		}
		actionS := actionC.Uninstantiate(s.Names)
		result = append(result, actionS.String())
	}
	reverseHints(result)
	return result
}

func contenders(d dynamics.Dwimmer, l term.SettingLine, n int) ([]*term.Setting, []float32) {
	allSettings := d.Continuations(term.Init())
	result, priorities := Top(l, allSettings, n)
	return result, priorities
}

func DoC(d dynamics.Dwimmer, a term.ActionC, s *term.SettingT) term.T {
	return d.Do(a.Instantiate(s.Args), s)
}

func setState(d dynamics.Dwimmer, s *term.SettingT, t term.T) term.T {
	d.SetStorage(t)
	return core.OK.T()
}

func getState(d dynamics.Dwimmer, s *term.SettingT) term.T {
	return core.Answer.T(d.GetStorage())
}

func ShowSettingS(d dynamics.Dwimmer, settingS *term.SettingS) {
	d.Clear()
	for _, line := range settingS.Lines() {
		d.Println(line)
	}
}