package parser

import (
	"context"
	"log/slog"
	"sync/atomic"

	"github.com/alex-savin/go-receipt-tracker/bus"
	"github.com/alex-savin/go-receipt-tracker/config"
	"github.com/alex-savin/go-receipt-tracker/utils"
	"github.com/sashabaranov/go-openai"
)

type OpenAi struct {
	id            string
	model         string
	opts          *config.Parser
	client        *openai.Client
	subscriptions map[string]chan bus.Event //
	bus           *bus.Bus
	log           *slog.Logger
	cancel        context.CancelFunc //
	end           uint32             // ensure the close methods are only called once
}

func NewOpenAi(cfg *config.Parser, bus *bus.Bus) *OpenAi {

	ai := &OpenAi{
		id:    cfg.Type,  // "openai",
		model: cfg.Model, // "gpt-4o-mini"
		opts:  cfg,
		bus:   bus,
	}
	return ai
}

func (ai *OpenAi) ID() string {
	return ai.id
}

func (ai *OpenAi) Type() string {
	return "parser"
}

func (ai *OpenAi) Init(log *slog.Logger) error {
	ai.client = openai.NewClient(ai.opts.ApiKey)
	ai.log = log

	return nil
}

func (ai *OpenAi) Serve() {
	if atomic.LoadUint32(&ai.end) == 1 {
		return
	}

	ai.subscribe("parser:" + ai.ID())
	ai.subscribe("parser:*")

	ctx, cancel := context.WithCancel(context.Background())
	ai.cancel = cancel

	go ai.eventLoop(ctx)
}

func (ai *OpenAi) subscribe(chn string) error {
	s, err := ai.bus.Subscribe(chn, ai.Type()+":"+ai.ID())
	if err != nil {
		ai.log.Error("couldn't subscribe to a channel", "channel", chn, "error", err.Error())
		return err
	}
	ai.subscriptions[chn] = s

	return nil
}

// eventLoop loops forever
func (ai *OpenAi) eventLoop(ctx context.Context) {
	ai.log.Debug(ai.ID() + " communication event loop started")
	defer ai.log.Debug(ai.ID() + " communication event loop halted")

	for {
		for chn, ch := range ai.subscriptions {
			select {
			case event := <-ch:
				switch event.Payload.(type) {
				case bus.Image:
					ai.log.Debug("got a new message to a channel", "channel", chn)

					res, err := ai.recognize(event.Payload.(bus.Image).Base64)
					if err != nil {
						ai.log.Error("got an error from parser ("+ai.ID()+")", "error", err)
					}
					err = ai.bus.Publish("telegram:publish", res)
					if err != nil {
						ai.log.Error("couldn't publish to a channel", "channel", "telegram:publish", "error", err.Error())
					}
				}
			case <-ctx.Done():
				ai.log.Info("stopping " + ai.ID() + " communication event loop")
				return
			}
		}
	}
}

func (ai *OpenAi) recognize(img string) (res string, err error) {
	resp, err := ai.client.CreateChatCompletion(
		context.Background(),
		openai.ChatCompletionRequest{
			Model:     openai.GPT4oMini,
			MaxTokens: 1000,
			Messages: []openai.ChatCompletionMessage{
				{
					Role: openai.ChatMessageRoleUser,
					MultiContent: []openai.ChatMessagePart{
						{
							Type: openai.ChatMessagePartTypeText,
							Text: config.Request,
						},
						{
							Type: openai.ChatMessagePartTypeImageURL,
							ImageURL: &openai.ChatMessageImageURL{
								URL:    img,
								Detail: openai.ImageURLDetailHigh,
							},
						},
					},
				},
			},
		},
	)

	if err != nil {
		ai.log.Error("error during recognition process", "%+v", resp.Choices[0].Message.Content)
		return "", err
	}
	if !utils.IsJSON(resp.Choices[0].Message.Content) {
		ai.log.Error("OpenAI returned not valid JSON", "%+v", resp.Choices[0].Message.Content)
		return "", err
	}

	ai.log.Debug("recognition output", "%+v", resp.Choices[0].Message.Content)

	return resp.Choices[0].Message.Content, nil
}