import { useRef, useState } from "react";
import { Box, Button, Group, Image, Paper, Stack, Text } from "@mantine/core";
import { RefreshCw, Stamp, X } from "lucide-react";

const MAX_STAMP_MB = 5;

export interface StampUploadProps {
  /** Stamp image as a data URL, or null when none is attached yet. */
  value: string | null;
  onChange: (dataUrl: string | null) => void;
  label?: string;
  description?: string;
}

/**
 * Company stamp/seal attachment for the contract signing modal. Reads the
 * picked image straight into a data URL because the signing endpoint takes
 * base64 in JSON (same transport as the drawn signature), not multipart.
 */
export function StampUpload({
  value,
  onChange,
  label = "Company stamp",
  description = "Attach your official company stamp or seal.",
}: StampUploadProps) {
  const inputRef = useRef<HTMLInputElement>(null);
  const [dragging, setDragging] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [fileName, setFileName] = useState<string | null>(null);

  const readFile = (file: File | undefined | null) => {
    if (!file) return;
    if (!file.type.startsWith("image/")) {
      setError("The stamp must be an image file (PNG or JPG).");
      return;
    }
    if (file.size > MAX_STAMP_MB * 1024 * 1024) {
      setError(`The stamp image must be under ${MAX_STAMP_MB} MB.`);
      return;
    }
    const reader = new FileReader();
    reader.onload = () => {
      setError(null);
      setFileName(file.name);
      onChange(typeof reader.result === "string" ? reader.result : null);
    };
    reader.onerror = () => setError("Could not read that file. Try another.");
    reader.readAsDataURL(file);
  };

  const openPicker = () => inputRef.current?.click();

  const clear = () => {
    setFileName(null);
    setError(null);
    onChange(null);
    if (inputRef.current) inputRef.current.value = "";
  };

  return (
    <Stack gap={6}>
      <Text size="sm" fw={500}>
        {label}
      </Text>

      <input
        ref={inputRef}
        type="file"
        accept="image/png,image/jpeg,image/webp"
        hidden
        onChange={(e) => readFile(e.currentTarget.files?.[0])}
      />

      {value ? (
        <Paper withBorder radius="md" p="sm">
          <Group gap="md" wrap="nowrap" align="center">
            <Box
              style={{
                background:
                  "repeating-conic-gradient(var(--mantine-color-gray-1) 0% 25%, transparent 0% 50%) 50% / 14px 14px",
                borderRadius: 8,
                flexShrink: 0,
                padding: 6,
              }}
            >
              <Image
                src={value}
                alt="Company stamp"
                fit="contain"
                h={92}
                w={92}
              />
            </Box>
            <Stack gap={4} style={{ flex: 1, minWidth: 0 }}>
              <Text size="sm" fw={500} truncate>
                {fileName ?? "Stamp attached"}
              </Text>
              <Text size="xs" c="dimmed">
                This stamp is applied next to your signature on the contract.
              </Text>
              <Group gap="xs" mt={2}>
                <Button
                  size="compact-xs"
                  variant="light"
                  color="edr-green"
                  leftSection={<RefreshCw size={13} />}
                  onClick={openPicker}
                >
                  Replace
                </Button>
                <Button
                  size="compact-xs"
                  variant="subtle"
                  color="red"
                  leftSection={<X size={13} />}
                  onClick={clear}
                >
                  Remove
                </Button>
              </Group>
            </Stack>
          </Group>
        </Paper>
      ) : (
        <Paper
          withBorder
          radius="md"
          p="lg"
          onClick={openPicker}
          onDragOver={(e) => {
            e.preventDefault();
            setDragging(true);
          }}
          onDragLeave={() => setDragging(false)}
          onDrop={(e) => {
            e.preventDefault();
            setDragging(false);
            readFile(e.dataTransfer.files?.[0]);
          }}
          style={{
            borderColor: dragging
              ? "var(--mantine-color-edr-green-6)"
              : undefined,
            borderStyle: "dashed",
            backgroundColor: dragging
              ? "var(--mantine-color-edr-green-0)"
              : undefined,
            cursor: "pointer",
          }}
        >
          <Stack gap={6} align="center">
            <Stamp size={26} color="var(--mantine-color-edr-green-6)" />
            <Text size="sm" fw={500}>
              Upload company stamp
            </Text>
            <Text size="xs" c="dimmed" ta="center">
              {description} Drop an image here or click to browse — PNG or JPG,
              up to {MAX_STAMP_MB} MB.
            </Text>
          </Stack>
        </Paper>
      )}

      {error && (
        <Text size="xs" c="red.7">
          {error}
        </Text>
      )}
    </Stack>
  );
}