package handlers

import (
	"net/http"
	"net/url"
	"strings"
	"time"

	"amnezia-share/internal/models"
	"amnezia-share/internal/share"
	"amnezia-share/internal/web"
)

func flashFromQuery(r *http.Request) (ok, errText string) {
	return r.URL.Query().Get("ok"), r.URL.Query().Get("err")
}

func redirectWithFlash(w http.ResponseWriter, r *http.Request, a *web.App, path string, ok, errText string) {
	u, _ := url.Parse(a.Cfg.AppURL(path))
	q := u.Query()
	if ok != "" {
		q.Set("ok", ok)
	}
	if errText != "" {
		q.Set("err", errText)
	}
	u.RawQuery = q.Encode()
	http.Redirect(w, r, u.String(), http.StatusSeeOther)
}

const adminPerPage = 20

type linkRow struct {
	models.ShareLink
	Status        share.LinkStatus
	ActiveConfigs int
}

type adminLinksView struct {
	adminLayout
	Links            []linkRow
	StatusFilter     string
	Page             int
	Total            int
	PerPage          int
	Detail           *models.ShareLink
	DetailStatus     share.LinkStatus
	Creations        []models.ShareCreation
	DeletedCreations []models.ShareCreation
	AllowedDurations []int
	AllowedServerIDs []int
	AllServers       []models.ServerInfo
}

// AdminLinksGet lists share links (paginated, filterable by status) and, when
// ?id= is present, shows one link's detail with its creations (share_links.php).
func AdminLinksGet(a *web.App) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		ctx := r.Context()
		ok, errText := flashFromQuery(r)
		view := adminLinksView{
			adminLayout:      newAdminLayout(a, r, "links"),
			StatusFilter:     r.URL.Query().Get("status"),
			Page:             queryInt(r, "page", 1),
			PerPage:          adminPerPage,
			AllowedDurations: share.AllowedDurations,
		}
		view.OK, view.Error = ok, errText
		if view.Page < 1 {
			view.Page = 1
		}

		links, err := a.Share.ListLinks(ctx, view.Page, view.PerPage, view.StatusFilter)
		if err != nil {
			view.Error = err.Error()
		}
		view.Total, _ = a.Share.CountLinks(ctx, view.StatusFilter)
		for _, l := range links {
			creations, _ := a.Share.ListCreationsForLink(ctx, l.ID)
			view.Links = append(view.Links, linkRow{
				ShareLink:     l,
				Status:        share.ClassifyLinkStatus(l, len(creations) > 0),
				ActiveConfigs: len(creations),
			})
		}

		if id := queryInt(r, "id", 0); id > 0 {
			if link, err := a.Share.LinkByID(ctx, id); err == nil && link != nil {
				view.Detail = link
				creations, _ := a.Share.ListCreationsForLink(ctx, id)
				view.DetailStatus = share.ClassifyLinkStatus(*link, len(creations) > 0)
				view.Creations = creations
				view.DeletedCreations, _ = a.Share.ListDeletedCreationsForLink(ctx, id)
				view.AllowedServerIDs = share.ParseAllowedServerIDs(link.AllowedServerIDs)
				view.AllServers = share.BuildGuestServers(ctx, a.Settings, a.Settings.ServerLabels(ctx))
			}
		}

		a.Render(w, r, "page_admin_links", view)
	}
}

func parseFormDate(v string) *time.Time {
	v = strings.TrimSpace(v)
	if v == "" {
		return nil
	}
	layouts := []string{"2006-01-02T15:04", "2006-01-02", time.RFC3339}
	for _, layout := range layouts {
		if t, err := time.Parse(layout, v); err == nil {
			return &t
		}
	}
	return nil
}

// AdminLinksPost handles link create/update/delete/extend/allowed-servers and
// per-creation deletion.
func AdminLinksPost(a *web.App) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		ctx := r.Context()
		action := r.FormValue("action")
		back := "admin/links"
		if id := r.FormValue("back_id"); id != "" {
			back += "?id=" + url.QueryEscape(id)
		}

		var err error
		var okMsg string

		switch action {
		case "create":
			days := formInt(r, "days", 30)
			maxUses := formInt(r, "max_uses", 5)
			subUntil := parseFormDate(r.FormValue("subscription_until"))
			link, cerr := a.Share.CreateLink(ctx, days, maxUses, subUntil)
			err = cerr
			if err == nil {
				okMsg = "Ссылка создана: #" + itoaHelper(link.ID)
			}

		case "update":
			linkID := formInt(r, "link_id", 0)
			validityDays := formInt(r, "validity_days", 30)
			floating := r.FormValue("floating_expiry") == "1"
			expiresAt := parseFormDate(r.FormValue("expires_at"))
			subUntil := parseFormDate(r.FormValue("subscription_until"))
			maxUses := formInt(r, "max_uses", 5)
			err = a.Share.UpdateLink(ctx, linkID, validityDays, floating, expiresAt, subUntil, maxUses)
			if err == nil {
				okMsg = "Срок ссылки обновлён."
			}

		case "delete":
			linkID := formInt(r, "link_id", 0)
			err = a.Share.DeleteLink(ctx, linkID)
			back = "admin/links"
			if err == nil {
				okMsg = "Ссылка удалена."
			}

		case "extend":
			linkID := formInt(r, "link_id", 0)
			days := formInt(r, "days", 30)
			err = a.Share.ExtendLinkByDays(ctx, linkID, days)
			if err == nil {
				okMsg = "Ссылка продлена."
			}

		case "set_allowed_servers":
			linkID := formInt(r, "link_id", 0)
			_ = r.ParseForm()
			var ids []int
			for _, v := range r.Form["server_ids[]"] {
				if n := formIntFromString(v, -1); n >= 0 {
					ids = append(ids, n)
				}
			}
			err = a.Share.SetAllowedServerIDs(ctx, linkID, ids)
			if err == nil {
				okMsg = "Список серверов обновлён."
			}

		case "delete_creation":
			linkID := formInt(r, "link_id", 0)
			creationID := formInt64(r, "creation_id", 0)
			err = a.Share.SoftDeleteCreation(ctx, a.Panel, a.Settings, linkID, creationID)
			if err == nil {
				okMsg = "Конфигурация удалена."
			}

		default:
			err = errUnknownAction
		}

		errText := ""
		if err != nil {
			errText = err.Error()
		}
		redirectWithFlash(w, r, a, back, okMsg, errText)
	}
}