package web

import (
	"html/template"
	"net/http"
	"sort"
	"time"

	"github.com/domagojzecevic/cammonitor/internal/auth"
	"github.com/domagojzecevic/cammonitor/internal/footage"
	webtemplates "github.com/domagojzecevic/cammonitor/internal/web/templates"
	"github.com/go-chi/chi/v5"
)

type Handler struct {
	index *footage.Index
}

type ShellData struct {
	Title       string
	User        *auth.User
	Months      []MonthGroup
	CurrentDate string
	ActiveTab   string
	Content     any
}

type MonthGroup struct {
	Label string
	Days  []string
}

type DayPageData struct {
	Date       string
	ImageCount int
	VideoCount int
}

func NewHandler(index *footage.Index) *Handler {
	return &Handler{index: index}
}

func (h *Handler) Index(w http.ResponseWriter, r *http.Request) {
	days := h.dayList()
	if len(days) == 0 {
		h.render(w, r, ShellData{
			Title: "CamMonitor",
			Content: DayPageData{
				Date: "No footage",
			},
		})
		return
	}

	http.Redirect(w, r, "/day/"+days[0]+"/images", http.StatusFound)
}

func (h *Handler) DayOverview(w http.ResponseWriter, r *http.Request) {
	date := chi.URLParam(r, "date")
	day, ok := h.day(date)
	if !ok {
		http.NotFound(w, r)
		return
	}

	h.render(w, r, ShellData{
		Title:       "CamMonitor " + date,
		CurrentDate: date,
		Content: DayPageData{
			Date:       date,
			ImageCount: len(day.Images),
			VideoCount: len(day.Videos),
		},
	})
}

func (h *Handler) render(w http.ResponseWriter, r *http.Request, data ShellData) {
	data.User, _ = auth.UserFromContext(r.Context())
	data.Months = groupDaysByMonth(h.dayList())

	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	if err := shellTemplate.ExecuteTemplate(w, "base", data); err != nil {
		http.Error(w, "render page failed", http.StatusInternalServerError)
	}
}

func (h *Handler) dayList() []string {
	if h.index == nil {
		return nil
	}
	return h.index.DayList()
}

func (h *Handler) day(date string) (*footage.DayEntry, bool) {
	if h.index == nil {
		return nil, false
	}
	return h.index.Day(date)
}

func groupDaysByMonth(days []string) []MonthGroup {
	groups := make(map[string][]string)
	labels := make([]string, 0)

	for _, day := range days {
		if len(day) != len("20060102") {
			continue
		}

		parsed, err := time.Parse("20060102", day)
		if err != nil {
			continue
		}

		label := parsed.Format("2006-01")
		if _, ok := groups[label]; !ok {
			labels = append(labels, label)
		}
		groups[label] = append(groups[label], day)
	}

	sort.Sort(sort.Reverse(sort.StringSlice(labels)))
	monthGroups := make([]MonthGroup, 0, len(labels))
	for _, label := range labels {
		monthGroups = append(monthGroups, MonthGroup{
			Label: label,
			Days:  groups[label],
		})
	}
	return monthGroups
}

var shellTemplate = template.Must(template.ParseFS(
	webtemplates.FS,
	webtemplates.Base,
	webtemplates.Day,
))