package handler

import (
	"fmt"
	"net/http"
	"spend-sparrow/internal/handler/middleware"
	"spend-sparrow/internal/service"
	t "spend-sparrow/internal/template/transaction"
	"spend-sparrow/internal/types"
	"spend-sparrow/internal/utils"
	"strconv"
	"time"

	"github.com/a-h/templ"
	"github.com/google/uuid"
)

type Transaction interface {
	Handle(router *http.ServeMux)
}

type TransactionImpl struct {
	s             service.Transaction
	account       service.Account
	treasureChest service.TreasureChest
	r             *Render
}

func NewTransaction(s service.Transaction, account service.Account, treasureChest service.TreasureChest, r *Render) Transaction {
	return TransactionImpl{
		s:             s,
		account:       account,
		treasureChest: treasureChest,
		r:             r,
	}
}

func (h TransactionImpl) Handle(r *http.ServeMux) {
	r.Handle("GET /transaction", h.handleTransactionPage())
	r.Handle("GET /transaction/{id}", h.handleTransactionItemComp())
	r.Handle("POST /transaction/{id}", h.handleUpdateTransaction())
	r.Handle("POST /transaction/recalculate", h.handleRecalculate())
	r.Handle("DELETE /transaction/{id}", h.handleDeleteTransaction())
}

func (h TransactionImpl) handleTransactionPage() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user := middleware.GetUser(r)
		if user == nil {
			utils.DoRedirect(w, r, "/auth/signin")
			return
		}

		filter := types.TransactionItemsFilter{
			AccountId:       r.URL.Query().Get("account-id"),
			TreasureChestId: r.URL.Query().Get("treasure-chest-id"),
			Error:           r.URL.Query().Get("error"),
		}

		transactions, err := h.s.GetAll(user, filter)
		if err != nil {
			handleError(w, r, err)
			return
		}

		accounts, err := h.account.GetAll(user)
		if err != nil {
			handleError(w, r, err)
			return
		}

		treasureChests, err := h.treasureChest.GetAll(user)
		if err != nil {
			handleError(w, r, err)
			return
		}

		accountMap, treasureChestMap := h.getTransactionData(accounts, treasureChests)

		items := t.TransactionItems(transactions, accountMap, treasureChestMap)
		if utils.IsHtmx(r) {
			h.r.Render(r, w, items)
		} else {
			comp := t.Transaction(items, filter, accounts, treasureChests)
			h.r.RenderLayout(r, w, comp, user)
		}
	}
}

func (h TransactionImpl) handleTransactionItemComp() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user := middleware.GetUser(r)
		if user == nil {
			utils.DoRedirect(w, r, "/auth/signin")
			return
		}

		accounts, err := h.account.GetAll(user)
		if err != nil {
			handleError(w, r, err)
			return
		}

		treasureChests, err := h.treasureChest.GetAll(user)
		if err != nil {
			handleError(w, r, err)
			return
		}

		id := r.PathValue("id")
		if id == "new" {
			comp := t.EditTransaction(nil, accounts, treasureChests)
			h.r.Render(r, w, comp)
			return
		}

		transaction, err := h.s.Get(user, id)
		if err != nil {
			handleError(w, r, err)
			return
		}

		var comp templ.Component
		if r.URL.Query().Get("edit") == "true" {
			comp = t.EditTransaction(transaction, accounts, treasureChests)
		} else {
			accountMap, treasureChestMap := h.getTransactionData(accounts, treasureChests)
			comp = t.TransactionItem(transaction, accountMap, treasureChestMap)
		}
		h.r.Render(r, w, comp)
	}
}

func (h TransactionImpl) handleUpdateTransaction() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user := middleware.GetUser(r)
		if user == nil {
			utils.DoRedirect(w, r, "/auth/signin")
			return
		}

		var (
			id  uuid.UUID
			err error
		)

		idStr := r.PathValue("id")
		if idStr != "new" {
			id, err = uuid.Parse(idStr)
			if err != nil {
				handleError(w, r, fmt.Errorf("could not parse Id: %w", service.ErrBadRequest))
				return
			}
		}

		accountIdStr := r.FormValue("account-id")
		var accountId *uuid.UUID
		if accountIdStr != "" {
			i, err := uuid.Parse(accountIdStr)
			if err != nil {
				handleError(w, r, fmt.Errorf("could not parse account id: %w", service.ErrBadRequest))
				return
			}
			accountId = &i
		}

		treasureChestIdStr := r.FormValue("treasure-chest-id")
		var treasureChestId *uuid.UUID
		if treasureChestIdStr != "" {
			i, err := uuid.Parse(treasureChestIdStr)
			if err != nil {
				handleError(w, r, fmt.Errorf("could not parse treasure chest id: %w", service.ErrBadRequest))
				return
			}
			treasureChestId = &i
		}

		valueF, err := strconv.ParseFloat(r.FormValue("value"), 64)
		if err != nil {
			handleError(w, r, fmt.Errorf("could not parse value: %w", service.ErrBadRequest))
			return
		}
		value := int64(valueF * service.DECIMALS_MULTIPLIER)

		timestamp, err := time.Parse("2006-01-02", r.FormValue("timestamp"))
		if err != nil {
			handleError(w, r, fmt.Errorf("could not parse timestamp: %w", service.ErrBadRequest))
			return
		}

		input := types.Transaction{
			Id:              id,
			AccountId:       accountId,
			TreasureChestId: treasureChestId,
			Value:           value,
			Timestamp:       timestamp,
			Party:           r.FormValue("party"),
			Description:     r.FormValue("description"),
		}

		var transaction *types.Transaction
		if idStr == "new" {
			transaction, err = h.s.Add(nil, user, input)
			if err != nil {
				handleError(w, r, err)
				return
			}
		} else {
			transaction, err = h.s.Update(user, input)
			if err != nil {
				handleError(w, r, err)
				return
			}
		}

		accounts, err := h.account.GetAll(user)
		if err != nil {
			handleError(w, r, err)
			return
		}

		treasureChests, err := h.treasureChest.GetAll(user)
		if err != nil {
			handleError(w, r, err)
			return
		}

		accountMap, treasureChestMap := h.getTransactionData(accounts, treasureChests)
		comp := t.TransactionItem(transaction, accountMap, treasureChestMap)
		h.r.Render(r, w, comp)
	}
}

func (h TransactionImpl) handleRecalculate() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user := middleware.GetUser(r)
		if user == nil {
			utils.DoRedirect(w, r, "/auth/signin")
			return
		}

		err := h.s.RecalculateBalances(user)
		if err != nil {
			handleError(w, r, err)
			return
		}

		utils.TriggerToastWithStatus(w, r, "success", "Balances recalculated, please refresh", http.StatusOK)
	}
}

func (h TransactionImpl) handleDeleteTransaction() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user := middleware.GetUser(r)
		if user == nil {
			utils.DoRedirect(w, r, "/auth/signin")
			return
		}

		id := r.PathValue("id")

		err := h.s.Delete(user, id)
		if err != nil {
			handleError(w, r, err)
			return
		}
	}
}

func (h TransactionImpl) getTransactionData(accounts []*types.Account, treasureChests []*types.TreasureChest) (map[uuid.UUID]string, map[uuid.UUID]string) {
	accountMap := make(map[uuid.UUID]string, 0)
	for _, account := range accounts {
		accountMap[account.Id] = account.Name
	}
	treasureChestMap := make(map[uuid.UUID]string, 0)
	root := ""
	for _, treasureChest := range treasureChests {
		if treasureChest.ParentId == nil {
			root = treasureChest.Name + " > "
			treasureChestMap[treasureChest.Id] = treasureChest.Name
		} else {
			treasureChestMap[treasureChest.Id] = root + treasureChest.Name
		}
	}
	return accountMap, treasureChestMap
}