package web

import (
	"io"
	"net/http"
	"path"
	"strings"

	"github.com/google/uuid"

	"plumber/internal/blob"
	"plumber/internal/geo"
	"plumber/internal/store"
)

type profilePage struct {
	page
	States         []struct{ Code, Name string }
	Questions      []store.RankedQuestion
	QuestionsLabel string
	UploadsEnabled bool
	Error          string
	StateVal       string
}

func (s *Server) handleProfileForm(w http.ResponseWriter, r *http.Request) {
	u := currentUser(r)
	if u == nil {
		http.Redirect(w, r, "/login?next=/profile", http.StatusSeeOther)
		return
	}
	s.renderProfile(w, r, u, "", u.State)
}

func (s *Server) handleProfile(w http.ResponseWriter, r *http.Request) {
	u := currentUser(r)
	if u == nil {
		http.Redirect(w, r, "/login?next=/profile", http.StatusSeeOther)
		return
	}
	if err := r.ParseMultipartForm(3 << 20); err != nil {
		s.renderProfile(w, r, u, "Could not read form (max 2MB for images).", u.State)
		return
	}
	want := s.sessions.GetString(r.Context(), "csrf")
	got := r.FormValue("_csrf")
	if want == "" || got != want {
		http.Error(w, "invalid csrf token", http.StatusForbidden)
		return
	}

	state := geo.NormalizeState(r.FormValue("state"))
	if !geo.ValidState(state) {
		s.renderProfile(w, r, u, "Choose a valid US state or leave it blank.", state)
		return
	}

	avatarURL := ""
	file, hdr, err := r.FormFile("avatar")
	if err == nil {
		defer file.Close()
		if !s.cfg.Blob.Enabled() {
			s.renderProfile(w, r, u, "Avatar uploads are not configured on this server.", state)
			return
		}
		ct := hdr.Header.Get("Content-Type")
		ext, contentType, ok := avatarType(hdr.Filename, ct)
		if !ok {
			s.renderProfile(w, r, u, "Avatar must be a JPEG, PNG, or WebP image.", state)
			return
		}
		if hdr.Size > 2<<20 {
			s.renderProfile(w, r, u, "Avatar must be 2MB or smaller.", state)
			return
		}
		key := path.Join("avatars", u.ID, uuid.NewString()+ext)
		limited := io.LimitReader(file, (2<<20)+1)
		url, upErr := s.cfg.Blob.Upload(r.Context(), blob.FileUpload{
			Key:         key,
			Body:        limited,
			ContentType: contentType,
			Size:        hdr.Size,
		})
		if upErr != nil {
			s.renderProfile(w, r, u, "Could not upload avatar. Try again later.", state)
			return
		}
		avatarURL = url
	} else if err != http.ErrMissingFile {
		s.renderProfile(w, r, u, "Could not read avatar file.", state)
		return
	}

	if err := s.store.UpdateProfile(r.Context(), u.ID, state, avatarURL); err != nil {
		http.Error(w, "could not save profile", http.StatusInternalServerError)
		return
	}
	s.sessions.Put(r.Context(), "flash", "Profile saved.")
	http.Redirect(w, r, "/profile", http.StatusSeeOther)
}

func avatarType(filename, contentType string) (ext, normalized string, ok bool) {
	contentType = strings.ToLower(strings.TrimSpace(contentType))
	filename = strings.ToLower(filename)
	switch {
	case strings.HasPrefix(contentType, "image/jpeg"), strings.HasSuffix(filename, ".jpg"), strings.HasSuffix(filename, ".jpeg"):
		return ".jpg", "image/jpeg", true
	case strings.HasPrefix(contentType, "image/png"), strings.HasSuffix(filename, ".png"):
		return ".png", "image/png", true
	case strings.HasPrefix(contentType, "image/webp"), strings.HasSuffix(filename, ".webp"):
		return ".webp", "image/webp", true
	default:
		return "", "", false
	}
}

func (s *Server) renderProfile(w http.ResponseWriter, r *http.Request, u *store.User, errMsg, stateVal string) {
	var (
		questions []store.RankedQuestion
		label     string
		err       error
	)
	if u.Admin() {
		label = "Questions you answered"
		questions, err = s.store.ListQuestionsAnsweredBy(r.Context(), u.ID)
	} else {
		label = "Your questions"
		questions, err = s.store.ListQuestionsByAuthor(r.Context(), u.ID)
	}
	if err != nil {
		http.Error(w, "could not load questions", http.StatusInternalServerError)
		return
	}
	if fresh, e := s.store.UserByID(r.Context(), u.ID); e == nil {
		u = fresh
	}
	p := s.basePage(r, "Profile")
	p.User = u
	s.exec(w, "profile", profilePage{
		page:           p,
		States:         geo.States,
		Questions:      questions,
		QuestionsLabel: label,
		UploadsEnabled: s.cfg.Blob.Enabled(),
		Error:          errMsg,
		StateVal:       stateVal,
	})
}