// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
// SPDX-License-Identifier: GPL-3.0-or-later

package app

import (
	"context"
	"errors"
	"fmt"
	"strings"

	"git.stormux.org/storm/cthulhu/internal/config"
	"git.stormux.org/storm/cthulhu/internal/preferences"
)

func (worker *preferencesWorker) preview(ctx context.Context, request preferences.Request) preferences.Response {
	if request.EchoPreview != "" {
		return worker.preview_echo_voice(ctx, request)
	}
	next := worker.settings
	if worker.editingActive {
		next = worker.editing
	}
	next.DefaultVoice.Rate = request.Values.Rate
	next.DefaultVoice.AveragePitch = request.Values.Pitch
	next.DefaultVoice.Gain = request.Values.Volume
	next.SpeechServerFactory = request.Values.SpeechServerFactory
	next.HardwareSpeechDevice = request.Values.HardwareSpeechDevice
	next.HardwareSpeechBaudRate = request.Values.HardwareSpeechBaudRate
	next.SpeechOutputModule = request.Values.SpeechOutputModule
	next.DefaultVoice.Family = request.Values.SpeechVoiceFamily
	next.UppercaseVoice = request.Values.UppercaseVoice
	next.HyperlinkVoice = request.Values.HyperlinkVoice
	next.SystemVoice = request.Values.SystemVoice
	// GUI feedback auditions the selected type; Cancel restores the committed
	// configuration, while Apply receives the complete unmodified draft.
	if kind := request.Values.VoiceType; kind != "" && kind != "default" {
		next.DefaultVoice = config.EffectiveVoice(next, kind)
		next.SystemVoice = config.Voice{}
	}
	response := worker.response("Speech settings previewed.", false)
	response.Preview = true
	if err := config.Validate(next); err != nil {
		response.Message = "Speech settings were not previewed: " + err.Error()
		return response
	}
	if err := worker.updateSpeech(ctx, next); err != nil {
		response.Message = "Speech settings were not previewed: " + err.Error()
		return response
	}
	response.Accepted = true
	return response
}

func (worker *preferencesWorker) preview_echo_voice(ctx context.Context, request preferences.Request) preferences.Response {
	response := worker.response("Speech settings previewed.", false)
	response.Preview = true
	var value *float64
	text := ""
	label := ""
	switch request.EchoPreview {
	case "rate":
		value = request.Values.EchoVoice.Rate
		label = "Key echo rate"
	case "pitch":
		value = request.Values.EchoVoice.AveragePitch
		label = "Key echo pitch"
	case "volume":
		value = request.Values.EchoVoice.Gain
		label = "Key echo volume"
	case "synthesizer":
		label = "Key echo speech synthesizer"
		text = request.Values.EchoSpeechServer
		if text == "" {
			text = "Default"
		}
	case "person":
		label = "Key echo person"
		text = "Default"
		if family := request.Values.EchoVoice.Family; family != nil {
			text = family.Name
			if language := strings.TrimSuffix(family.Lang+"-"+family.Dialect, "-"); language != "" {
				text += " (" + language + ")"
			}
		}
	}
	if value != nil {
		text = fmt.Sprintf("%.1f", *value)
	}
	if !request.Values.UseCustomEchoVoice || text == "" {
		response.Message = "Choose a custom echo voice and a valid echo control value."
		return response
	}
	// Preview only echo settings. Control labels and ordinary output retain
	// the active profile's main voice; the draft is never committed here.
	next := worker.settings
	next.UseCustomEchoVoice = true
	next.UseCustomEchoSpeechServer = request.Values.UseCustomEchoSpeechServer
	next.EchoSpeechServer = request.Values.EchoSpeechServer
	next.EchoVoice = request.Values.EchoVoice
	if err := config.Validate(next); err != nil {
		response.Message = "Speech settings were not previewed: " + err.Error()
		return response
	}
	if err := worker.updateSpeech(ctx, next); err != nil {
		response.Message = "Speech settings were not previewed: " + err.Error()
		return response
	}
	if worker.announceEchoPreview != nil {
		if !request.EchoPreviewFocus {
			label = ""
		}
		worker.announceEchoPreview(label, text)
	}
	response.Accepted = true
	return response
}

func echo_preview_speech(label, value string) speechRequest {
	parts := []readAllPart{}
	if label != "" {
		parts = append(parts, readAllPart{Text: label, VoiceType: "default"})
	}
	parts = append(parts, readAllPart{Text: value, VoiceType: "echo"})
	// Both parts belong to one cancellable request and wait for completion.
	// No second voice can cancel the first part merely by being queued next.
	return speechRequest{Text: value, Role: "text", Cause: "echo-voice-preview", ReadAll: parts}
}

func (worker *preferencesWorker) restorePreview(ctx context.Context) preferences.Response {
	response := worker.response("Speech settings restored.", false)
	if err := worker.updateSpeech(ctx, worker.effective_settings(worker.settings)); err != nil {
		response.Message = "Speech settings could not be restored: " + err.Error()
		return response
	}
	response.Accepted = true
	response.Close = true
	return response
}

func (worker *preferencesWorker) updateSpeech(ctx context.Context, next config.Settings) error {
	if worker.updater == nil {
		return errors.New("speech is disabled or this backend cannot change settings")
	}
	if updater, ok := worker.updater.(interface {
		UpdateConfiguration(context.Context, config.Settings) error
	}); ok {
		return updater.UpdateConfiguration(ctx, next)
	}
	if updater, ok := worker.updater.(speechSettingsUpdater); ok {
		if next.UseCustomEchoVoice {
			return errors.New("this speech backend cannot use a custom echo voice")
		}
		return updater.UpdateSettings(ctx, speechSettingsFromConfig(next))
	}
	return errors.New("this backend cannot change speech settings")
}