"use client"

import { useMemo, useState, type ReactNode } from "react"
import { Folder, Tag, type LucideIcon } from "lucide-react"
import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs"
import { Button } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select"
import { useMailAccounts } from "@/lib/api/hooks/use-mail-queries"
import { useLabels } from "@/lib/api/hooks/use-folder-label-queries"
import { useCreateUnifiedFolder, useUnifiedFolders } from "@/lib/api/hooks/use-unified-folder-queries"
import { useImapFoldersForAccount } from "@/lib/api/hooks/use-imap-folders"
import { buildImapFolderSettingsTree } from "@/lib/mail-settings/imap-folder-tree"
import { SettingsSectionHeader } from "@/components/gmail/settings/settings-section-header"
import { SettingsSyncBanner } from "@/components/gmail/settings/settings-sync-banner"
import { useAuthReady } from "@/lib/api/use-auth-ready"
import { buildFolderTreeFromUnified } from "@/lib/mail-settings/unified-folder-tree"
import { useSidebarNav } from "@/lib/sidebar-nav-context"
import { isSystemNavLabelId } from "@/lib/sidebar-nav-data"
import { NavColorPickerTrigger } from "@/components/gmail/nav/nav-color-picker-trigger"
import { DEFAULT_NAV_COLOR } from "@/lib/nav-color"
import {
  flattenLabelRowsForSettings,
  FolderSettingsTree,
  ImapFolderSettingsTree,
  NavLabelSettingsCard,
} from "@/components/gmail/settings/nav-item-settings-card"

function SettingsFormHeading({
  icon: Icon,
  children,
}: {
  icon: LucideIcon
  children: ReactNode
}) {
  return (
    <div className="flex items-center gap-2 text-sm font-medium text-foreground">
      <Icon className="size-4 shrink-0 opacity-70" aria-hidden />
      {children}
    </div>
  )
}

function NavSettingsListPanel({
  title,
  icon: Icon,
  loading,
  emptyTitle,
  emptyDescription,
  children,
}: {
  title: string
  icon?: LucideIcon
  loading: boolean
  emptyTitle: string
  emptyDescription?: string
  children?: ReactNode
}) {
  return (
    <section className="space-y-3">
      <div className="flex items-center gap-2">
        {Icon ? <Icon className="size-4 shrink-0 opacity-70" aria-hidden /> : null}
        <h3 className="text-sm font-medium text-foreground">{title}</h3>
      </div>
      {loading ? (
        <div
          className="min-h-[120px] rounded-lg border border-border bg-muted/20"
          aria-hidden
        />
      ) : children ? (
        children
      ) : (
        <div className="flex min-h-[120px] flex-col items-center justify-center gap-1 rounded-lg border border-dashed border-border bg-muted/10 px-4 py-8 text-center">
          <p className="text-sm text-foreground">{emptyTitle}</p>
          {emptyDescription ? (
            <p className="max-w-sm text-xs text-muted-foreground">{emptyDescription}</p>
          ) : null}
        </div>
      )}
    </section>
  )
}

export function LabelsFoldersSettingsSection() {
  return (
    <>
      <SettingsSectionHeader
        title="Libellés et dossiers"
        description="Mêmes réglages que dans la barre latérale : couleur, affichage dans les listes, arborescence, renommage."
      />
      <Tabs defaultValue="labels">
        <TabsList>
          <TabsTrigger value="labels">Libellés</TabsTrigger>
          <TabsTrigger value="folders-global">Dossiers globaux</TabsTrigger>
          <TabsTrigger value="folders-account">Dossiers par compte</TabsTrigger>
        </TabsList>
        <TabsContent value="labels" className="mt-4">
          <LabelsPanel />
        </TabsContent>
        <TabsContent value="folders-global" className="mt-4">
          <UnifiedFoldersPanel />
        </TabsContent>
        <TabsContent value="folders-account" className="mt-4">
          <ImapAccountFoldersPanel />
        </TabsContent>
      </Tabs>
    </>
  )
}

function LabelsPanel() {
  const { ready, authenticated } = useAuthReady()
  const nav = useSidebarNav()
  const { isPending } = useLabels()
  const [name, setName] = useState("")
  const [color, setColor] = useState(DEFAULT_NAV_COLOR)

  const userLabels = useMemo(
    () =>
      flattenLabelRowsForSettings(
        nav.labelRows.filter((row) => !isSystemNavLabelId(row.id))
      ),
    [nav.labelRows]
  )

  const listLoading = ready && authenticated && isPending && userLabels.length === 0

  return (
    <div className="space-y-6">
      <p className="text-sm text-muted-foreground">
        Cliquez sur un libellé pour modifier couleur, visibilité et sous-libellés — comme le menu
        clic droit dans la barre latérale.
      </p>

      <div className="rounded-lg border border-border p-4 space-y-3">
        <SettingsFormHeading icon={Tag}>Nouveau libellé</SettingsFormHeading>
        <div className="flex flex-wrap items-end gap-2">
          <div className="min-w-[160px] flex-1 space-y-1">
            <Label className="text-xs" htmlFor="new-label-name">
              Nom
            </Label>
            <div className="flex items-center gap-1">
              <NavColorPickerTrigger
                value={color}
                onChange={setColor}
                aria-label="Couleur du libellé"
              />
              <Input
                id="new-label-name"
                value={name}
                onChange={(e) => setName(e.target.value)}
                className="flex-1"
              />
            </div>
          </div>
          <Button
            type="button"
            className="shrink-0"
            disabled={!name.trim()}
            onClick={() => {
              nav.addLabelRowFromSidebar(name.trim(), color)
              setName("")
            }}
          >
            Créer
          </Button>
        </div>
      </div>

      <NavSettingsListPanel
        title="Vos libellés"
        icon={Tag}
        loading={listLoading}
        emptyTitle="Aucun libellé personnalisé"
        emptyDescription="Utilisez le formulaire ci-dessus pour en créer un."
      >
        {userLabels.length > 0 ? (
          <ul className="space-y-2">
            {userLabels.map((row) => (
              <li key={row.id}>
                <NavLabelSettingsCard
                  id={row.id}
                  name={row.label}
                  color={row.color}
                  depth={row.depth}
                />
              </li>
            ))}
          </ul>
        ) : null}
      </NavSettingsListPanel>
    </div>
  )
}

function UnifiedFoldersPanel() {
  const { ready, authenticated } = useAuthReady()
  const createFolder = useCreateUnifiedFolder()
  const { data: folders = [], isFetching, isError, refetch, isPending } =
    useUnifiedFolders("global")

  const [name, setName] = useState("")
  const [color, setColor] = useState(DEFAULT_NAV_COLOR)
  const [parentId, setParentId] = useState<string>("__root__")

  const visible = folders.filter((f) => f.scope === "global")
  const tree = useMemo(() => buildFolderTreeFromUnified(visible), [visible])

  const parentOptions = useMemo(() => {
    const opts: { value: string; label: string }[] = [{ value: "__root__", label: "Racine" }]
    const walk = (nodes: typeof tree, depth: number) => {
      for (const n of nodes) {
        opts.push({
          value: n.id,
          label: `${"\u2003".repeat(depth * 2)}${n.label}`,
        })
        if (n.children?.length) walk(n.children, depth + 1)
      }
    }
    walk(tree, 0)
    return opts
  }, [tree])

  const listLoading = ready && authenticated && isPending && visible.length === 0

  return (
    <div className="space-y-4">
      <p className="text-sm text-muted-foreground">
        Dossiers Ultimail globaux — organisation virtuelle cross-comptes.
      </p>
      <SettingsSyncBanner isFetching={isFetching} isError={isError} onRetry={() => refetch()} />

      <div className="rounded-lg border border-border p-4 space-y-3">
        <SettingsFormHeading icon={Folder}>Nouveau dossier</SettingsFormHeading>
        <div className="flex flex-wrap items-end gap-2">
          <div className="min-w-[160px] flex-1 space-y-1">
            <Label className="text-xs" htmlFor="new-folder-name-global">
              Nom
            </Label>
            <div className="flex items-center gap-1">
              <NavColorPickerTrigger
                value={color}
                onChange={setColor}
                aria-label="Couleur du dossier"
              />
              <Input
                id="new-folder-name-global"
                value={name}
                onChange={(e) => setName(e.target.value)}
                className="flex-1"
              />
            </div>
          </div>
          <div className="min-w-[200px] flex-1 space-y-1">
            <Label className="text-xs">Emplacement</Label>
            <Select value={parentId} onValueChange={setParentId}>
              <SelectTrigger>
                <SelectValue />
              </SelectTrigger>
              <SelectContent>
                {parentOptions.map((opt) => (
                  <SelectItem key={opt.value} value={opt.value}>
                    {opt.label}
                  </SelectItem>
                ))}
              </SelectContent>
            </Select>
          </div>
          <Button
            type="button"
            className="shrink-0"
            disabled={!name.trim() || createFolder.isPending}
            onClick={() => {
              const parent = parentId === "__root__" ? undefined : parentId
              createFolder.mutate({
                name: name.trim(),
                color,
                parent_id: parent,
              })
              setName("")
            }}
          >
            Créer
          </Button>
        </div>
      </div>

      <NavSettingsListPanel
        title="Vos dossiers"
        icon={Folder}
        loading={listLoading}
        emptyTitle="Aucun dossier Ultimail"
        emptyDescription="Utilisez le formulaire ci-dessus pour en créer un."
      >
        {visible.length > 0 ? <FolderSettingsTree nodes={tree} /> : null}
      </NavSettingsListPanel>
    </div>
  )
}

function ImapAccountFoldersPanel() {
  const { ready, authenticated } = useAuthReady()
  const { data: accounts = [] } = useMailAccounts()
  const [accountId, setAccountId] = useState("")
  const selectedAccountId = accountId || accounts[0]?.id
  const {
    data: folders = [],
    isFetching,
    isError,
    refetch,
    isPending,
  } = useImapFoldersForAccount(selectedAccountId)

  const tree = useMemo(
    () =>
      selectedAccountId
        ? buildImapFolderSettingsTree(folders, selectedAccountId)
        : [],
    [folders, selectedAccountId]
  )

  const listLoading = ready && authenticated && isPending && folders.length === 0

  return (
    <div className="space-y-4">
      <p className="text-sm text-muted-foreground">
        Dossiers synchronisés depuis vos serveurs mail (IMAP). Masquez ceux que vous ne voulez
        pas voir dans la barre latérale.
      </p>
      <SettingsSyncBanner isFetching={isFetching} isError={isError} onRetry={() => refetch()} />

      <div className="max-w-xs space-y-1">
        <Label className="text-xs">Compte mail</Label>
        <Select
          value={selectedAccountId ?? ""}
          onValueChange={setAccountId}
          disabled={accounts.length === 0}
        >
          <SelectTrigger>
            <SelectValue placeholder="Choisir un compte" />
          </SelectTrigger>
          <SelectContent>
            {accounts.map((a) => (
              <SelectItem key={a.id} value={a.id}>
                {a.email}
              </SelectItem>
            ))}
          </SelectContent>
        </Select>
      </div>

      <NavSettingsListPanel
        title="Dossiers IMAP"
        icon={Folder}
        loading={listLoading}
        emptyTitle="Aucun dossier IMAP personnalisé"
        emptyDescription="Les dossiers système (Boîte de réception, Envoyés…) restent dans la navigation principale. Les dossiers personnalisés apparaissent ici après synchronisation."
      >
        {tree.length > 0 ? <ImapFolderSettingsTree nodes={tree} /> : null}
      </NavSettingsListPanel>
    </div>
  )
}