package api

import (
	"fmt"
	"net/http"
	"sync"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/sandrodach/mindsift/internal/auth"
)

// Journal: one ordinary note per day, opened (and created on first use) by date. The web app shows the
// days below each other with a calendar; the notes can be shared and searched like any other.

var journalMu sync.Mutex // one creation at a time, so a day never gets two notes

var (
	journalWeekdays = []string{"Sonntag", "Montag", "Dienstag", "Mittwoch", "Donnerstag", "Freitag", "Samstag"}
	journalMonths   = []string{"Januar", "Februar", "März", "April", "Mai", "Juni", "Juli", "August", "September", "Oktober", "November", "Dezember"}
)

// journalTitle: "Freitag, 30. Oktober 2026"
func journalTitle(day time.Time) string {
	return fmt.Sprintf("%s, %d. %s %d", journalWeekdays[day.Weekday()], day.Day(), journalMonths[day.Month()-1], day.Year())
}

func (s *Server) handleGetJournal(w http.ResponseWriter, r *http.Request) {
	days, err := s.store.JournalDays(auth.GetUserID(r.Context()))
	if err != nil {
		writeError(w, http.StatusInternalServerError, "Journal konnte nicht geladen werden")
		return
	}
	writeJSON(w, http.StatusOK, map[string]interface{}{"days": days})
}

// handleOpenJournalDay returns the note of a day and creates it when there is none yet.
func (s *Server) handleOpenJournalDay(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	date := chi.URLParam(r, "date")
	day, err := time.Parse("2006-01-02", date)
	if err != nil {
		writeError(w, http.StatusBadRequest, "Ungültiges Datum (erwartet JJJJ-MM-TT)")
		return
	}
	journalMu.Lock()
	defer journalMu.Unlock()
	docID, err := s.store.JournalDocID(userID, date)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "Journal konnte nicht geladen werden")
		return
	}
	if docID != "" {
		if doc, err := s.store.GetDocumentByID(userID, docID); err == nil {
			writeJSON(w, http.StatusOK, doc)
			return
		}
	}
	doc, err := s.store.CreateDocument(userID, "", journalTitle(day), "📅", "", nil, nil, false)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Tag konnte nicht angelegt werden")
		return
	}
	if err := s.store.SetJournalDay(userID, date, doc.ID); err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Tag konnte nicht angelegt werden")
		return
	}
	s.broadcastDocToAuthorizedUsers(doc.ID, "DOC_CREATED")
	writeJSON(w, http.StatusCreated, doc)
}