package screens

import (
	"context"
	"fmt"

	"example.com/m/bot"
	"github.com/NicoNex/echotron/v3"
	"github.com/rs/zerolog/log"
)

const addPurchaseCreativesPerPage = 5
const addPurchaseProjectsPerPage = 6

type AddPurchase struct {
	WorkspaceID   string
	ProjectID     string
	ProjectTitle  string
	CreativeID    string
	CreativeTitle string
	ProjectPage   int
	CreativePage  int
	ActivePicker  string // "" | "project_list" | "creative_list"
	BackState     bot.State
	lastProjects  map[string]string
	lastCreatives map[string]string
}

func (s *AddPurchase) Enter(b *bot.Bot, mode bot.RenderMode) {
	jwt, err := s.ensureJWT(b)
	if err != nil {
		log.Error().Err(err).Msg("Failed to get JWT")
		b.SendNew("❌ Ошибка авторизации. Попробуйте /start", bot.Keyboard())
		return
	}

	s.renderSelection(b, mode, jwt)
}

func (s *AddPurchase) renderSelection(b *bot.Bot, mode bot.RenderMode, jwt string) {
	text := "<i>… › Закупы › Создание</i>\n\n<b>Создание закупа</b>\n\n"
	text += "Выберите проект и креатив.\n\n"

	var buttons [][]echotron.InlineKeyboardButton

	projectLabel := "Проект: не выбрано"
	if s.ProjectTitle != "" {
		projectLabel = fmt.Sprintf("Проект: %s", s.ProjectTitle)
	}
	creativeLabel := "Креатив: не выбрано"
	if s.CreativeTitle != "" {
		creativeLabel = fmt.Sprintf("Креатив: %s", s.CreativeTitle)
	}

	if s.ActivePicker == "" {
		buttons = append(buttons, bot.Row(
			bot.Button(projectLabel, "pick_project"),
		))
		buttons = append(buttons, bot.Row(
			bot.Button(creativeLabel, "pick_creative"),
		))
	}

	switch s.ActivePicker {
	case "project_list":
		page, err := b.Backend.GetProjects(
			context.Background(),
			jwt,
			s.WorkspaceID,
			s.ProjectPage+1,
			addPurchaseProjectsPerPage,
		)
		if err != nil {
			log.Error().Err(err).Msg("Failed to get projects")
			b.SendNew("❌ Не удалось загрузить проекты", bot.Keyboard())
			return
		}

		s.lastProjects = make(map[string]string)
		for _, project := range page.Items {
			s.lastProjects[project.ID] = project.Title
		}

		if len(page.Items) == 0 {
			text += "У вас нет проектов. Создайте проект и попробуйте снова.\n\n"
		} else {
			pageInfo := ""
			if page.Pages > 1 {
				pageInfo = fmt.Sprintf(" <i>(стр. %d/%d)</i>", page.Page, page.Pages)
			}

			text += fmt.Sprintf("Проекты%s\n\n", pageInfo)
			for _, project := range page.Items {
				buttons = append(buttons, bot.Row(
					bot.Button(project.Title, fmt.Sprintf("project:%s", project.ID)),
				))
			}

			var navRow []echotron.InlineKeyboardButton
			if s.ProjectPage > 0 {
				navRow = append(navRow, bot.Button("←", "prev_project"))
			}
			if s.ProjectPage+1 < page.Pages {
				navRow = append(navRow, bot.Button("→", "next_project"))
			}
			if len(navRow) > 0 {
				buttons = append(buttons, navRow)
			}
		}

		buttons = append(buttons, bot.Row(
			bot.Button("← Назад", "back_to_selection"),
		))

	case "creative_list":
		if s.ProjectID == "" {
			text += "Сначала выберите проект, чтобы увидеть список креативов.\n\n"
			buttons = append(buttons, bot.Row(
				bot.Button("← Назад", "back_to_selection"),
			))
			break
		}

		page, err := b.Backend.GetCreatives(
			context.Background(),
			jwt,
			s.WorkspaceID,
			&s.ProjectID,
			false,
			s.CreativePage+1,
			addPurchaseCreativesPerPage,
		)
		if err != nil {
			log.Error().Err(err).Msg("Failed to get creatives")
			b.SendNew("❌ Не удалось загрузить креативы", bot.Keyboard())
			return
		}

		s.lastCreatives = make(map[string]string)
		for _, creative := range page.Items {
			s.lastCreatives[creative.ID] = creative.Name
		}

		if len(page.Items) == 0 {
			text += `Для создания закупа сначала нужно создать креатив.

Вернитесь назад и создайте креатив в разделе <b>Креативы</b>`
		} else {
			pageInfo := ""
			if page.Pages > 1 {
				pageInfo = fmt.Sprintf(" <i>(стр. %d/%d)</i>", page.Page, page.Pages)
			}

			text += fmt.Sprintf("Креативы%s\n\n", pageInfo)

			for _, creative := range page.Items {
				buttons = append(buttons, bot.Row(
					bot.Button(creative.Name, fmt.Sprintf("creative:%s", creative.ID)),
				))
			}

			var navRow []echotron.InlineKeyboardButton
			if s.CreativePage > 0 {
				navRow = append(navRow, bot.Button("←", "prev_creative"))
			}
			if s.CreativePage+1 < page.Pages {
				navRow = append(navRow, bot.Button("→", "next_creative"))
			}
			if len(navRow) > 0 {
				buttons = append(buttons, navRow)
			}
		}

		buttons = append(buttons, bot.Row(
			bot.Button("← Назад", "back_to_selection"),
		))
	}

	if s.ActivePicker == "" {
		if s.ProjectID != "" && s.CreativeID != "" {
			buttons = append(buttons, bot.Row(
				bot.Button("← Отмена", "back"),
				bot.Button("→ Далее", "next"),
			))
		} else {
			buttons = append(buttons, bot.Row(
				bot.Button("← Отмена", "back"),
			))
		}
	}

	keyboard := bot.Keyboard(buttons...)
	b.Render(text, keyboard, mode)
}

func (s *AddPurchase) ensureJWT(b *bot.Bot) (string, error) {
	if b.Session.JWT != "" {
		return b.Session.JWT, nil
	}

	jwt, err := b.Backend.GetJWTByTelegramID(context.Background(), b.ChatID)
	if err != nil {
		return "", err
	}

	b.Session.JWT = jwt
	return jwt, nil
}

func (s *AddPurchase) HandleCallback(b *bot.Bot, u *echotron.Update) {
	if u.CallbackQuery == nil || u.CallbackQuery.Data == "" {
		return
	}

	data := u.CallbackQuery.Data

	switch data {
	case "back":
		if s.BackState != nil {
			b.SetState(s.BackState, bot.EditMessage)
		}

	case "pick_project":
		s.ActivePicker = "project_list"
		s.Enter(b, bot.EditMessage)

	case "pick_creative":
		s.ActivePicker = "creative_list"
		s.Enter(b, bot.EditMessage)

	case "back_to_selection":
		s.ActivePicker = ""
		s.Enter(b, bot.EditMessage)

	case "prev_project":
		if s.ProjectPage > 0 {
			s.ProjectPage--
		}
		s.Enter(b, bot.EditMessage)

	case "next_project":
		s.ProjectPage++
		s.Enter(b, bot.EditMessage)

	case "prev_creative":
		if s.CreativePage > 0 {
			s.CreativePage--
		}
		s.Enter(b, bot.EditMessage)

	case "next_creative":
		s.CreativePage++
		s.Enter(b, bot.EditMessage)

	case "next":
		if s.ProjectID != "" && s.CreativeID != "" {
			b.SetState(&SelectChannelsForPurchase{
				WorkspaceID:   s.WorkspaceID,
				ProjectID:     s.ProjectID,
				ProjectTitle:  s.ProjectTitle,
				CreativeID:    s.CreativeID,
				CreativeTitle: s.CreativeTitle,
				Channels:      []PurchaseChannelInput{},
				BackState:     s.BackState,
			}, bot.EditMessage)
		}

	default:
		if len(data) > 8 && data[:8] == "project:" {
			projectID := data[8:]
			if s.lastProjects != nil {
				s.ProjectTitle = s.lastProjects[projectID]
			}
			s.ProjectID = projectID
			s.CreativeID = ""
			s.CreativeTitle = ""
			s.CreativePage = 0
			s.ActivePicker = ""
			s.Enter(b, bot.EditMessage)
			return
		}
		if len(data) > 9 && data[:9] == "creative:" {
			creativeID := data[9:]
			if s.lastCreatives != nil {
				s.CreativeTitle = s.lastCreatives[creativeID]
			}
			s.CreativeID = creativeID
			s.ActivePicker = ""
			s.Enter(b, bot.EditMessage)
			return
		} else {
			s.Enter(b, bot.NewMessage)
		}
	}
}

func (s *AddPurchase) HandleMessage(_ *bot.Bot, _ *echotron.Update) { return }

func (s *AddPurchase) Handle(_ *bot.Bot, _ *echotron.Update) { return }