import { useState } from "react"
import {
  useWidgets,
  useCreateWidget,
  useUpdateWidget,
  useDeleteWidget,
} from "@/api/widgets"
import { useDataSources } from "@/api/data-sources"
import type { Widget, DisplayHint, KeyMapping } from "@/api/types"
import { Button } from "@/components/ui/button"
import {
  Card,
  CardContent,
  CardDescription,
  CardHeader,
  CardTitle,
} from "@/components/ui/card"
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
  DialogFooter,
} from "@/components/ui/dialog"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select"
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from "@/components/ui/alert-dialog"
import { Badge } from "@/components/ui/badge"
import { Plus, Pencil, Trash2, X } from "lucide-react"
import { toast } from "sonner"

const DISPLAY_HINTS: DisplayHint[] = ["icon_value", "text_block", "key_value"]


const EMPTY: Widget = {
  id: 0,
  name: "",
  display_hint: "icon_value",
  data_source_id: 0,
  mappings: [],
  max_data_size: 2048,
}

export function WidgetsPage() {
  const { data: widgets = [], isLoading } = useWidgets()
  const { data: sources = [] } = useDataSources()
  const create = useCreateWidget()
  const update = useUpdateWidget()
  const del = useDeleteWidget()

  const [editing, setEditing] = useState<Widget | null>(null)
  const [deleting, setDeleting] = useState<number | null>(null)

  function openNew() {
    const nextId =
      widgets.length > 0 ? Math.max(...widgets.map((w) => w.id)) + 1 : 1
    setEditing({
      ...EMPTY,
      id: nextId,
      data_source_id: sources[0]?.id ?? 0,
    })
  }

  async function save() {
    if (!editing) return
    const isNew = !widgets.some((w) => w.id === editing.id)
    try {
      if (isNew) {
        await create.mutateAsync(editing)
        toast.success("Widget created")
      } else {
        await update.mutateAsync(editing)
        toast.success("Widget updated")
      }
      setEditing(null)
    } catch (e) {
      toast.error(String(e))
    }
  }

  async function confirmDelete() {
    if (deleting == null) return
    try {
      await del.mutateAsync(deleting)
      toast.success("Widget deleted")
    } catch (e) {
      toast.error(String(e))
    }
    setDeleting(null)
  }

  const sourceName = (id: number) =>
    sources.find((s) => s.id === id)?.name ?? `#${id}`

  if (isLoading) return <div className="text-muted-foreground p-4">Loading…</div>

  return (
    <div className="space-y-6">
      <div className="flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-semibold tracking-tight">Widgets</h1>
          <p className="text-muted-foreground text-sm">
            Display primitives bound to data sources
          </p>
        </div>
        <Button onClick={openNew}>
          <Plus className="mr-2 h-4 w-4" />
          Add Widget
        </Button>
      </div>

      {widgets.length === 0 ? (
        <Card>
          <CardContent className="py-12 text-center">
            <p className="text-muted-foreground">No widgets configured yet.</p>
          </CardContent>
        </Card>
      ) : (
        <div className="grid gap-3">
          {widgets.map((w) => (
            <Card key={w.id}>
              <CardHeader className="flex flex-row items-center justify-between py-3">
                <div className="space-y-1">
                  <CardTitle className="text-base">{w.name}</CardTitle>
                  <CardDescription className="flex items-center gap-2">
                    <Badge variant="secondary">{w.display_hint}</Badge>
                    <span>source: {sourceName(w.data_source_id)}</span>
                    <span>{w.mappings.length} mapping(s)</span>
                  </CardDescription>
                </div>
                <div className="flex gap-1">
                  <Button
                    variant="ghost"
                    size="icon"
                    onClick={() => setEditing({ ...w })}
                  >
                    <Pencil className="h-4 w-4" />
                  </Button>
                  <Button
                    variant="ghost"
                    size="icon"
                    onClick={() => setDeleting(w.id)}
                  >
                    <Trash2 className="h-4 w-4" />
                  </Button>
                </div>
              </CardHeader>
            </Card>
          ))}
        </div>
      )}

      <Dialog open={!!editing} onOpenChange={(o) => !o && setEditing(null)}>
        <DialogContent className="max-w-lg">
          <DialogHeader>
            <DialogTitle>
              {editing && widgets.some((w) => w.id === editing.id)
                ? "Edit Widget"
                : "New Widget"}
            </DialogTitle>
          </DialogHeader>
          {editing && (
            <WidgetForm
              value={editing}
              onChange={setEditing}
              sources={sources}
            />
          )}
          <DialogFooter>
            <Button variant="outline" onClick={() => setEditing(null)}>
              Cancel
            </Button>
            <Button onClick={save} disabled={!editing?.name}>
              Save
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>

      <AlertDialog
        open={deleting != null}
        onOpenChange={(o) => !o && setDeleting(null)}
      >
        <AlertDialogContent>
          <AlertDialogHeader>
            <AlertDialogTitle>Delete widget?</AlertDialogTitle>
            <AlertDialogDescription>
              This will permanently remove this widget. Layout references will
              become dangling.
            </AlertDialogDescription>
          </AlertDialogHeader>
          <AlertDialogFooter>
            <AlertDialogCancel>Cancel</AlertDialogCancel>
            <AlertDialogAction onClick={confirmDelete}>
              Delete
            </AlertDialogAction>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>
    </div>
  )
}


function WidgetForm({
  value,
  onChange,
  sources,
}: {
  value: Widget
  onChange: (w: Widget) => void
  sources: { id: number; name: string }[]
}) {
  const set = <K extends keyof Widget>(k: K, v: Widget[K]) =>
    onChange({ ...value, [k]: v })

  function addMapping() {
    set("mappings", [...value.mappings, { source_path: "", target_key: "" }])
  }

  function updateMapping(i: number, m: KeyMapping) {
    const next = [...value.mappings]
    next[i] = m
    set("mappings", next)
  }

  function removeMapping(i: number) {
    set(
      "mappings",
      value.mappings.filter((_, idx) => idx !== i),
    )
  }

  return (
    <div className="grid gap-4 py-2">
      <div className="grid gap-2">
        <Label>Name</Label>
        <Input
          value={value.name}
          onChange={(e) => set("name", e.target.value)}
          placeholder="e.g. weather"
        />
      </div>
      <div className="grid gap-2">
        <Label>Display Hint</Label>
        <Select
          value={value.display_hint}
          onValueChange={(v) => set("display_hint", v as DisplayHint)}
        >
          <SelectTrigger>
            <SelectValue />
          </SelectTrigger>
          <SelectContent>
            {DISPLAY_HINTS.map((h) => (
              <SelectItem key={h} value={h}>
                {h}
              </SelectItem>
            ))}
          </SelectContent>
        </Select>
      </div>
      <div className="grid gap-2">
        <Label>Data Source</Label>
        <Select
          value={String(value.data_source_id)}
          onValueChange={(v) => set("data_source_id", Number(v))}
        >
          <SelectTrigger>
            <SelectValue />
          </SelectTrigger>
          <SelectContent>
            {sources.map((s) => (
              <SelectItem key={s.id} value={String(s.id)}>
                {s.name}
              </SelectItem>
            ))}
          </SelectContent>
        </Select>
      </div>
      <div className="grid gap-2">
        <Label>Max Data Size (bytes)</Label>
        <Input
          type="number"
          value={value.max_data_size}
          onChange={(e) => set("max_data_size", Number(e.target.value))}
          min={1}
        />
      </div>
      <div className="grid gap-2">
        <div className="flex items-center justify-between">
          <Label>Key Mappings</Label>
          <Button variant="outline" size="sm" onClick={addMapping}>
            <Plus className="mr-1 h-3 w-3" />
            Add
          </Button>
        </div>
        {value.mappings.map((m, i) => (
          <div key={i} className="flex items-center gap-2">
            <Input
              value={m.source_path}
              onChange={(e) =>
                updateMapping(i, { ...m, source_path: e.target.value })
              }
              placeholder="$.path.to.value"
              className="flex-1"
            />
            <span className="text-muted-foreground text-sm">→</span>
            <Input
              value={m.target_key}
              onChange={(e) =>
                updateMapping(i, { ...m, target_key: e.target.value })
              }
              placeholder="target_key"
              className="flex-1"
            />
            <Button
              variant="ghost"
              size="icon"
              onClick={() => removeMapping(i)}
            >
              <X className="h-3 w-3" />
            </Button>
          </div>
        ))}
      </div>
    </div>
  )
}