package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"time"

	"github.com/matst80/slask-finder/pkg/index"
)

type Message struct {
	TimeStamp *int64
	Type      string
	Content   interface{}
}

type CartItem struct {
	Sku   string `json:"sku"`
	Name  string `json:"name"`
	Price int    `json:"price"`
	Image string `json:"image"`
}

type CartGrain struct {
	storageMessages []Message
	Id              string     `json:"id"`
	Items           []CartItem `json:"items"`
	TotalPrice      int        `json:"totalPrice"`
}

type Grain interface {
	GetId() string
	GetLastChange() int64
	HandleMessage(message *Message, isReplay bool, reply *CartGrain) error
	GetStorageMessage(since int64) []Message
}

func (c *CartGrain) GetId() string {
	return c.Id
}

func (c *CartGrain) GetLastChange() int64 {
	if len(c.storageMessages) == 0 {
		return 0
	}
	return *c.storageMessages[len(c.storageMessages)-1].TimeStamp
}

func getItemData(sku string) (*CartItem, error) {
	res, err := http.Get("https://slask-finder.tornberg.me/api/get/" + sku)
	if err != nil {
		return nil, err
	}
	defer res.Body.Close()
	var item index.DataItem
	err = json.NewDecoder(res.Body).Decode(&item)
	if err != nil {
		return nil, err
	}
	price := item.GetPrice()
	if price == 0 {
		priceField, ok := item.GetFields()[4]
		if ok {

			pricef, ok := priceField.(float64)
			if !ok {
				price, ok = priceField.(int)
				if !ok {
					return nil, fmt.Errorf("invalid price type")
				}
			} else {
				price = int(pricef)
			}
		}
	}
	return &CartItem{
		Sku:   item.Sku,
		Name:  item.Title,
		Price: price,
		Image: item.Img,
	}, nil
}

func (c *CartGrain) AddItem(sku string, reply *CartGrain) error {
	cartItem, err := getItemData(sku)
	if err != nil {
		return err
	}
	return c.HandleMessage(&Message{
		Type:    "append",
		Content: *cartItem,
	}, false, reply)
}

func (c *CartGrain) GetStorageMessage(since int64) []Message {
	if since == 0 {
		return c.storageMessages
	}
	ret := make([]Message, 0)
	for _, message := range c.storageMessages {
		if *message.TimeStamp > since {
			ret = append(ret, message)
		}
	}
	return ret
}

func (c *CartGrain) HandleMessage(message *Message, isReplay bool, reply *CartGrain) error {
	log.Printf("Handling message %s", message.Type)
	if message.TimeStamp == nil {
		now := time.Now().Unix()
		message.TimeStamp = &now
	}
	var err error
	switch message.Type {
	case "add":
		sku, ok := message.Content.(string)
		if !ok {
			err = fmt.Errorf("invalid content type")
		} else {
			return c.AddItem(sku, reply)
		}
	case "append":
		item, ok := message.Content.(CartItem)
		if !ok {
			err = fmt.Errorf("invalid content type")
		} else {
			c.Items = append(c.Items, item)
			c.TotalPrice += item.Price
		}
	default:
		err = fmt.Errorf("unknown message type")
	}
	if !isReplay {
		c.storageMessages = append(c.storageMessages, *message)
	}
	*reply = *c
	return err
}