import { useState } from "react";
import { Text } from "@/components/ui/text";
import { validateVendorDocument } from "@/domain/vendor-portal/lib/document-validation";
import {
  isApprovalRequired,
  validateUpliftAmount,
  type UpliftFormValues,
} from "@/domain/vendor-portal/lib/uplift-validation";

type UpliftRequestFormProps = {
  mode: "create" | "revise";
  currentNte?: number;
  initialRequested?: string;
  initialReason?: string;
  hasExistingEvidence?: boolean;
  submitting: boolean;
  uploadingPercent: number | undefined;
  errorMessage: string;
  onSubmit: (values: UpliftFormValues) => void;
  onCancel?: () => void;
};

export function UpliftRequestForm({
  mode,
  currentNte,
  initialRequested = "",
  initialReason = "",
  hasExistingEvidence = false,
  submitting,
  uploadingPercent,
  errorMessage,
  onSubmit,
  onCancel,
}: UpliftRequestFormProps) {
  const [requested, setRequested] = useState(initialRequested);
  const [reason, setReason] = useState(initialReason);
  const [evidenceFile, setEvidenceFile] = useState<File | undefined>();
  const [formError, setFormError] = useState("");

  const showApprovalFields = mode === "revise" || isApprovalRequired(requested, currentNte);

  const submit = (event: React.FormEvent) => {
    event.preventDefault();
    const amount = Number.parseFloat(requested);
    const validationError = validateUpliftAmount(requested, currentNte, reason, {
      file: evidenceFile,
      hasExisting: hasExistingEvidence,
      mode,
    });
    setFormError(validationError);
    if (validationError) {
      return;
    }
    onSubmit({ amount, reason: reason.trim(), evidenceFile });
  };

  const chooseFile = (file?: File) => {
    const validationMessage = file ? validateVendorDocument(file) : undefined;
    setFormError(validationMessage ?? "");
    setEvidenceFile(file);
  };

  const shownError = errorMessage || formError;
  const busy = submitting || uploadingPercent !== undefined;

  return (
    <form
      onSubmit={(event) => void submit(event)}
      className="vp-uplift-form"
      aria-label={mode === "revise" ? "Revise uplift request" : "Request NTE uplift"}
    >
      {mode === "create" && (
        <div className="vp-row">
          <strong>Current NTE</strong>
          <span>${Number(currentNte ?? 0).toFixed(2)}</span>
        </div>
      )}
      <div className="vp-row">
        <strong>
          <label htmlFor={`uplift-amount-${mode}`}>New total NTE</label>
        </strong>
        <input
          id={`uplift-amount-${mode}`}
          type="number"
          step="0.01"
          min="0"
          className="vp-input"
          value={requested}
          onChange={(event) => {
            setRequested(event.target.value);
            setFormError("");
          }}
          placeholder="0.00"
        />
      </div>
      {showApprovalFields && (
        <>
          <div className="vp-row">
            <strong>
              <label htmlFor={`uplift-reason-${mode}`}>Reason</label>
            </strong>
            <textarea
              id={`uplift-reason-${mode}`}
              className="vp-textarea"
              value={reason}
              onChange={(event) => {
                setReason(event.target.value);
                setFormError("");
              }}
              placeholder="Why is the uplift needed?"
            />
          </div>
          <div className="vp-row">
            <strong>
              <label htmlFor={`uplift-evidence-${mode}`}>Evidence (PDF/JPG/PNG)</label>
            </strong>
            <input
              id={`uplift-evidence-${mode}`}
              type="file"
              className="vp-input"
              accept=".pdf,.jpg,.jpeg,.png,application/pdf,image/jpeg,image/png"
              onChange={(event) => chooseFile(event.target.files?.[0])}
            />
          </div>
        </>
      )}
      {uploadingPercent !== undefined && (
        <div className="vp-row" role="status" aria-live="polite">
          <strong>Uploading</strong>
          <span>{uploadingPercent}%</span>
        </div>
      )}
      <Text variant="error" when={Boolean(shownError)}>
        {shownError}
      </Text>
      <div className="vp-actions">
        <button type="submit" className="vp-btn vp-btn-primary" disabled={busy}>
          {busy ? "Submitting…" : mode === "revise" ? "Submit revision" : "Request uplift"}
        </button>
        {mode === "revise" && (
          <button type="button" className="vp-btn vp-btn-ghost" onClick={onCancel} disabled={busy}>
            Cancel
          </button>
        )}
      </div>
    </form>
  );
}