package chat

import (
	"bytes"
	"encoding/json"
	caos_errs "github.com/caos/zitadel/internal/errors"
	"github.com/caos/zitadel/internal/notification/providers"
	"net/http"
	"net/url"
	"unicode/utf8"
)

type Chat struct {
	URL        *url.URL
	SplitCount int
}

func InitChatProvider(config ChatConfig) (*Chat, error) {
	url, err := url.Parse(config.Url)
	if err != nil {
		return nil, err
	}
	return &Chat{
		URL:        url,
		SplitCount: config.SplitCount,
	}, nil
}

func (chat *Chat) CanHandleMessage(_ providers.Message) bool {
	return true
}

func (chat *Chat) HandleMessage(message providers.Message) error {
	contentText := message.GetContent()
	for _, splittedMsg := range splitMessage(contentText, chat.SplitCount) {
		chatMsg := &ChatMessage{Text: splittedMsg}
		if err := chat.SendMessage(chatMsg); err != nil {
			return err
		}
	}
	return nil
}

func (chat *Chat) SendMessage(message providers.Message) error {
	chatMsg, ok := message.(*ChatMessage)
	if !ok {
		return caos_errs.ThrowInternal(nil, "EMAIL-s8JLs", "message is not ChatMessage")
	}
	req, err := json.Marshal(chatMsg)
	if err != nil {
		return caos_errs.ThrowInternal(err, "PROVI-s8uie", "Could not unmarshal content")
	}

	_, err = http.Post(chat.URL.String(), "application/json; charset=UTF-8", bytes.NewReader(req))
	if err != nil {
		return caos_errs.ThrowInternal(err, "PROVI-si93s", "unable to send message")
	}
	return nil
}

func splitMessage(message string, count int) []string {
	if count == 0 {
		return []string{message}
	}
	var splits []string
	var l, r int
	for l, r = 0, count; r < len(message); l, r = r, r+count {
		for !utf8.RuneStart(message[r]) {
			r--
		}
		splits = append(splits, message[l:r])
	}
	splits = append(splits, message[l:])
	return splits
}