"use client";

import { useCallback, useState } from "react";
import { useDropzone } from "react-dropzone";
import { Upload, FileText, CheckCircle2, XCircle, Loader2 } from "lucide-react";
import {
  Sheet, SheetContent, SheetDescription, SheetHeader, SheetTitle, SheetTrigger,
} from "@/components/ui/sheet";
import { Button } from "@/components/ui/button";
import { Progress } from "@/components/ui/progress";
import {
  Select, SelectContent, SelectItem, SelectTrigger, SelectValue,
} from "@/components/ui/select";
import { useUploadDocument, useProgress, type ProgressEvent } from "@/lib/api/documents";
import { DOC_TYPE_OPTIONS } from "@/lib/doc-types";

/*
 * Upload sheet — drag-drop zone + doc-type selector, with live SSE
 * progress for the most-recent upload. Intentionally sequential:
 * a single file at a time keeps the SSE subscription simple and
 * matches how the FastAPI processor handles one task_id per file.
 *
 * The "auto" option is upload-only — it triggers backend classification.
 * After upload, the inline DocumentTypeEditor shows the resolved doc_type
 * and uses DOC_TYPE_OPTIONS directly (no "auto" entry).
 */

const DOC_TYPES: { value: string; label: string }[] = [
  { value: "auto", label: "זיהוי אוטומטי" },
  ...DOC_TYPE_OPTIONS,
];

type UploadRow = {
  id: string;
  filename: string;
  taskId: string | null;
  error?: string;
};

function statusLabel(event: ProgressEvent | null): string {
  if (!event) return "מתחיל…";
  if (event.status === "queued") return "בתור";
  if (event.status === "processing")
    return event.step ? `בעיבוד · ${event.step}` : "בעיבוד";
  if (event.status === "completed") return "הושלם";
  if (event.status === "unknown") return "הושלם";
  if (event.status === "failed") return event.error ?? "נכשל";
  return event.status;
}

function progressPercent(event: ProgressEvent | null): number {
  if (!event) return 5;
  if (event.status === "queued") return 10;
  if (event.status === "processing") return 55;
  if (event.status === "completed") return 100;
  if (event.status === "unknown") return 100;
  if (event.status === "failed") return 100;
  return 25;
}

function UploadRowView({ row, caseNumber }: { row: UploadRow; caseNumber: string }) {
  const progress = useProgress(row.taskId, caseNumber);
  const pct = row.error ? 100 : progressPercent(progress);
  const failed = row.error || progress?.status === "failed";
  const done = progress?.status === "completed" || progress?.status === "unknown";

  return (
    <li className="rounded-lg border border-rule bg-parchment/40 px-4 py-3 space-y-2">
      <div className="flex items-center gap-2">
        {done ? (
          <CheckCircle2 className="w-4 h-4 text-success shrink-0" />
        ) : failed ? (
          <XCircle className="w-4 h-4 text-danger shrink-0" />
        ) : (
          <Loader2 className="w-4 h-4 text-gold animate-spin shrink-0" />
        )}
        <FileText className="w-4 h-4 text-ink-muted shrink-0" />
        <span className="text-sm text-ink truncate flex-1" title={row.filename}>
          {row.filename}
        </span>
        <span
          className={`text-[0.72rem] tabular-nums shrink-0 ${
            done ? "text-success" : failed ? "text-danger" : "text-ink-muted"
          }`}
        >
          {row.error ?? statusLabel(progress)}
        </span>
      </div>
      <Progress
        value={pct}
        className={failed ? "[&>div]:bg-danger" : done ? "[&>div]:bg-success" : ""}
      />
    </li>
  );
}

export function UploadSheet({ caseNumber }: { caseNumber: string }) {
  const [open, setOpen] = useState(false);
  const [docType, setDocType] = useState("auto");
  const [rows, setRows] = useState<UploadRow[]>([]);
  const mutate = useUploadDocument(caseNumber);

  const onDrop = useCallback(
    async (files: File[]) => {
      for (const file of files) {
        const rowId = crypto.randomUUID();
        setRows((r) => [
          ...r,
          { id: rowId, filename: file.name, taskId: null },
        ]);
        try {
          const res = await mutate.mutateAsync({ file, docType });
          setRows((r) =>
            r.map((row) =>
              row.id === rowId ? { ...row, taskId: res.task_id } : row,
            ),
          );
        } catch (e) {
          setRows((r) =>
            r.map((row) =>
              row.id === rowId
                ? { ...row, error: e instanceof Error ? e.message : "שגיאה" }
                : row,
            ),
          );
        }
      }
    },
    [docType, mutate],
  );

  const dropzone = useDropzone({
    onDrop,
    accept: {
      "application/pdf": [".pdf"],
      "application/msword": [".doc"],
      "application/vnd.openxmlformats-officedocument.wordprocessingml.document": [".docx"],
      "text/plain": [".txt"],
      "text/markdown": [".md"],
    },
    maxSize: 50 * 1024 * 1024,
  });

  return (
    <Sheet open={open} onOpenChange={setOpen}>
      <SheetTrigger asChild>
        <Button variant="outline" size="sm">
          <Upload className="w-4 h-4 me-1" /> העלאת מסמכים
        </Button>
      </SheetTrigger>
      <SheetContent side="left" className="w-full sm:max-w-lg" dir="rtl">
        <SheetHeader>
          <SheetTitle className="text-navy">העלאת מסמכים לתיק {caseNumber}</SheetTitle>
          <SheetDescription className="text-ink-muted">
            PDF, DOCX, DOC, TXT, MD — עד 50MB לקובץ. הקבצים מעובדים ברקע
            והסטטוס מתעדכן בזמן אמת.
          </SheetDescription>
        </SheetHeader>

        <div className="mt-5 space-y-4 px-4 overflow-y-auto flex-1 min-h-0">
          <div>
            <label className="block text-sm font-medium text-navy mb-1.5">
              סיווג
            </label>
            <Select value={docType} onValueChange={setDocType} dir="rtl">
              <SelectTrigger><SelectValue /></SelectTrigger>
              <SelectContent>
                {DOC_TYPES.map((t) => (
                  <SelectItem key={t.value} value={t.value}>{t.label}</SelectItem>
                ))}
              </SelectContent>
            </Select>
          </div>

          <div
            {...dropzone.getRootProps()}
            className={`
              rounded-lg border-2 border-dashed p-8 text-center cursor-pointer
              transition-colors
              ${
                dropzone.isDragActive
                  ? "border-gold bg-gold-wash"
                  : "border-rule bg-parchment/40 hover:bg-gold-wash/50 hover:border-gold/60"
              }
            `}
          >
            <input {...dropzone.getInputProps()} />
            <Upload className="w-8 h-8 mx-auto mb-2 text-gold-deep" />
            <p className="text-sm text-navy font-medium">
              {dropzone.isDragActive
                ? "שחרר כאן להעלאה"
                : "גרור קבצים או לחץ לבחירה"}
            </p>
            <p className="text-[0.72rem] text-ink-muted mt-1">
              ניתן להעלות מספר קבצים בבת אחת
            </p>
          </div>

          {rows.length > 0 && (
            <ul className="space-y-2">
              {rows.map((row) => (
                <UploadRowView key={row.id} row={row} caseNumber={caseNumber} />
              ))}
            </ul>
          )}
        </div>
      </SheetContent>
    </Sheet>
  );
}