package quiz

import (
	"context"
	"net/http"
	"strconv"
	"time"

	httpCtx "forge.cadoles.com/wpetit/kouiz/internal/http/context"
	"forge.cadoles.com/wpetit/kouiz/internal/http/handler/webui/auth"
	"forge.cadoles.com/wpetit/kouiz/internal/http/handler/webui/common"
	"forge.cadoles.com/wpetit/kouiz/internal/http/handler/webui/quiz/component"
	"forge.cadoles.com/wpetit/kouiz/internal/store"
	"github.com/a-h/templ"
	"github.com/pkg/errors"
	"gorm.io/gorm"
)

func (h *Handler) getQuizPage(w http.ResponseWriter, r *http.Request) {
	vmodel, err := h.fillQuizPageVModel(r)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	quizPage := component.QuizPage(*vmodel)
	templ.Handler(quizPage).ServeHTTP(w, r)
}

func (h *Handler) fillQuizPageVModel(r *http.Request) (*component.QuizPageVModel, error) {
	vmodel := &component.QuizPageVModel{
		PlayDelay: h.playDelay,
	}

	err := common.FillViewModel(
		r.Context(), vmodel, r,
		h.fillQuizPagePlayer,
		h.fillQuizPageTurn,
	)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return vmodel, nil
}

func (h *Handler) fillQuizPagePlayer(ctx context.Context, vmodel *component.QuizPageVModel, r *http.Request) error {
	player, err := h.getRequestPlayer(r)
	if err != nil {
		return errors.WithStack(err)
	}

	vmodel.Player = player

	return nil
}

func (h *Handler) fillQuizPageTurn(ctx context.Context, vmodel *component.QuizPageVModel, r *http.Request) error {
	turn, err := h.store.GetQuizTurn(ctx, h.playInterval, h.playPeriod)
	if err != nil {
		return errors.WithStack(err)
	}

	vmodel.CurrentTurn = turn

	return nil
}

func (h *Handler) getRequestPlayer(r *http.Request) (*store.Player, error) {
	ctx := r.Context()
	user := auth.ContextUser(ctx)

	player, err := h.store.UpsertPlayer(ctx, user.Name, user.Email, user.Provider)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return player, nil
}

func (h *Handler) handleSelectEntryForm(w http.ResponseWriter, r *http.Request) {
	player, err := h.getRequestPlayer(r)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	selectEntryForm := component.NewSelectEntryForm()

	if err := selectEntryForm.Handle(r); err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	vmodel, err := h.fillQuizPageVModel(r)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	if errs := selectEntryForm.Validate(); errs != nil {
		page := component.QuizPage(*vmodel)
		templ.Handler(page).ServeHTTP(w, r)

		return
	}

	rawSelectedEntry, exists := selectEntryForm.Field("entry").Get("value")
	if !exists {
		page := component.QuizPage(*vmodel)
		templ.Handler(page).ServeHTTP(w, r)

		return
	}

	selectedEntry, err := strconv.ParseUint(rawSelectedEntry.(string), 10, 64)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	ctx := r.Context()

	turn, err := h.store.GetQuizTurn(ctx, h.playInterval, h.playPeriod)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	err = h.store.Do(ctx, func(db *gorm.DB) error {
		err := db.Model(&player).Updates(map[string]any{
			"selected_at":    time.Now().UTC(),
			"selected_entry": &selectedEntry,
			"selected_turn":  turn.ID,
		}).Error
		if err != nil {
			return errors.WithStack(err)
		}

		return nil
	})
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	baseURL := httpCtx.BaseURL(ctx)

	http.Redirect(w, r, baseURL.String(), http.StatusTemporaryRedirect)
}

func (h *Handler) handleAnswerForm(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	player, err := h.getRequestPlayer(r)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	if player.SelectedEntry == nil {
		h.handleError(w, r, errors.New("missing player selected entry"))
		return
	}

	answerForm := component.NewAnswerForm()

	if err := answerForm.Handle(r); err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	vmodel, err := h.fillQuizPageVModel(r)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	if errs := answerForm.Validate(); errs != nil {
		page := component.QuizPage(*vmodel)
		templ.Handler(page).ServeHTTP(w, r)

		return
	}

	rawAnswerIndex, exists := answerForm.Field("answer").Get("value")
	if !exists {
		page := component.QuizPage(*vmodel)
		templ.Handler(page).ServeHTTP(w, r)

		return
	}

	selectedAnswerIndex, err := strconv.ParseInt(rawAnswerIndex.(string), 10, 64)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	now := time.Now().UTC()

	if player.SelectedAt.UTC().Add(h.playDelay + time.Duration(float64(h.playDelay)*0.10)).Before(now) {
		err = h.store.Tx(ctx, func(db *gorm.DB) error {
			result := db.Model(&player).Updates(map[string]any{
				"selected_answer": selectedAnswerIndex,
				"played_at":       time.Now().UTC(),
			}).Where("played_at = ?", player.PlayedAt)

			if result.Error != nil {
				return errors.WithStack(err)
			}

			if result.RowsAffected != 1 {
				return errors.New("unexpected number of updated player")
			}

			return nil
		})
		if err != nil {
			h.handleError(w, r, errors.WithStack(err))
			return
		}

		h.handleError(w, r, common.NewError("delay expired", "Vous avez malheureusement trop tardé à répondre ! Réessayez au prochain tour !", http.StatusBadRequest))
		return
	}

	turn, err := h.store.GetQuizTurn(ctx, h.playInterval, h.playPeriod)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	var selectedEntry *store.QuizEntry
	for _, e := range turn.Entries {
		if *player.SelectedEntry != e.ID {
			continue
		}

		selectedEntry = e
		break
	}

	if selectedEntry == nil {
		h.handleError(w, r, errors.Errorf("invalid selected entry '%d'", *player.SelectedEntry))
		return
	}

	if selectedAnswerIndex < 0 || int(selectedAnswerIndex) >= len(selectedEntry.Propositions) {
		h.handleError(w, r, errors.Errorf("invalid selected answer index '%d'", selectedAnswerIndex))
		return
	}

	selectedAnswer := selectedEntry.Propositions[selectedAnswerIndex]

	won := selectedAnswer == selectedEntry.Answer

	err = h.store.Tx(ctx, func(db *gorm.DB) error {
		newScore := player.Score
		if won {
			newScore += 2 * int(selectedEntry.Level+1)
		}

		result := db.Model(&player).Updates(map[string]any{
			"score":           newScore,
			"selected_answer": selectedAnswerIndex,
			"played_at":       time.Now().UTC(),
		}).Where("played_at = ?", player.PlayedAt)

		if result.Error != nil {
			return errors.WithStack(err)
		}

		if result.RowsAffected != 1 {
			return errors.New("unexpected number of updated player")
		}

		return nil
	})
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	baseURL := httpCtx.BaseURL(ctx)
	baseURL = baseURL.JoinPath("/quiz/result")

	http.Redirect(w, r, baseURL.String(), http.StatusSeeOther)
}

func (h *Handler) handleError(w http.ResponseWriter, r *http.Request, err error) {
	common.HandleError(w, r, errors.WithStack(err))
}