package handlers

import (
	"fmt"
	"log/slog"
	"net/http"
	"strconv"

	"github.com/go-chi/chi/v5"

	"qbank/internal/auth"
	"qbank/internal/db"
)

type QuestionHandler struct {
	auth   *auth.Manager
	repo   *db.Repo
	render *Renderer
}

func NewQuestionHandler(a *auth.Manager, repo *db.Repo, r *Renderer) *QuestionHandler {
	return &QuestionHandler{auth: a, repo: repo, render: r}
}

func (h *QuestionHandler) Show(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	user := auth.UserFromCtx(r.Context())

	q, answers, err := h.repo.GetQuestion(id)
	if err != nil {
		HTTPError(w, http.StatusNotFound)
		return
	}

	stats, _ := h.repo.GetStatsForUser(user.ID, []string{id})

	data := BaseData(h.auth, r)
	data["Question"] = q
	data["Answers"] = answers
	data["Stat"] = stats[id]

	h.render.Render(w, http.StatusOK, "question", data)
}

func (h *QuestionHandler) Edit(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	if !h.auth.CheckCSRF(r) {
		HTTPError(w, http.StatusForbidden)
		return
	}

	r.Body = http.MaxBytesReader(w, r.Body, 1<<20)
	if err := r.ParseForm(); err != nil {
		HTTPError(w, http.StatusBadRequest)
		return
	}

	_, answers, err := h.repo.GetQuestion(id)
	if err != nil {
		HTTPError(w, http.StatusNotFound)
		return
	}

	text := r.FormValue("q_text")
	source := r.FormValue("source")
	correctIdx, _ := strconv.Atoi(r.FormValue("correct"))

	if err := h.repo.UpdateQuestion(id, text, source); err != nil {
		slog.Error("update question", "err", err)
		HTTPError(w, http.StatusInternalServerError)
		return
	}

	updates := make([]db.AnswerUpdate, len(answers))
	for i, a := range answers {
		updates[i] = db.AnswerUpdate{
			ID:        a.ID,
			Text:      r.FormValue(fmt.Sprintf("a_text_%d", i)),
			IsCorrect: i == correctIdx,
		}
	}
	if err := h.repo.UpdateAnswers(updates); err != nil {
		slog.Error("update answers", "err", err)
		HTTPError(w, http.StatusInternalServerError)
		return
	}

	h.auth.SetFlash(r, "Question saved.")
	http.Redirect(w, r, "/questions/"+id, http.StatusSeeOther)
}

func (h *QuestionHandler) Delete(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	if !h.auth.CheckCSRF(r) {
		HTTPError(w, http.StatusForbidden)
		return
	}

	r.Body = http.MaxBytesReader(w, r.Body, 4096)
	r.ParseForm()

	if err := h.repo.DeleteQuestion(id); err != nil {
		slog.Error("delete question", "err", err)
		HTTPError(w, http.StatusInternalServerError)
		return
	}

	h.auth.SetFlash(r, "Question deleted.")
	http.Redirect(w, r, "/", http.StatusSeeOther)
}