import { useMemo, useState } from "react";
import { Button, Dialog, DocumentationHelpLink, DismissibleAlert, FormField, ToggleSwitch, useUnsavedChanges, useUnsavedDraftGuard, type ApiSettings } from "@govoplan/core-webui";
import { createApproval, type ApprovalDraft, type ApprovalRequest } from "../../api/approvals";
import ApprovalStepsEditor, { emptyApprovalStep } from "./ApprovalStepsEditor";
import { APPROVALS_FIELD_DOCUMENTATION, APPROVALS_I18N } from "./interfacePatterns";

export default function ApprovalRequestDialog({ settings, onClose, onSaved }: { settings: ApiSettings; onClose: () => void; onSaved: (value: ApprovalRequest) => void }) {
  const [baseline] = useState<ApprovalDraft>(() => initialDraft());
  const [draft, setDraft] = useState<ApprovalDraft>(baseline);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState("");
  const { requestDiscard } = useUnsavedChanges();
  const valid = useMemo(() => Boolean(draft.title.trim() && draft.subject_module.trim() && draft.subject_type.trim() && draft.subject_id.trim() && /^[0-9a-f]{64}$/.test(draft.subject_digest) && draft.steps.every((step) => step.key.trim() && step.label.trim() && step.selectors.every((selector) => selector.value.trim()))), [draft]);
  const dirty = draftKey(draft) !== draftKey(baseline);

  async function save(): Promise<boolean> {
    setBusy(true);
    setError("");
    try {
      onSaved(await createApproval(settings, draft));
      return true;
    } catch (reason) {
      setError(reason instanceof Error ? reason.message : "The Approval request could not be created.");
      return false;
    } finally {
      setBusy(false);
    }
  }

  useUnsavedDraftGuard({
    dirty,
    onSave: save,
    onDiscard: () => setDraft(baseline),
    title: "i18n:govoplan-approvals.unsaved_title",
    message: "i18n:govoplan-approvals.unsaved_message"
  });

  function requestClose() {
    if (busy) return;
    if (dirty) requestDiscard(onClose);
    else onClose();
  }

  return <Dialog open title="New Approval request" onClose={requestClose} closeDisabled={busy} portal className="approval-request-dialog" footer={<><Button onClick={requestClose} disabled={busy} disabledReason={busy ? APPROVALS_I18N.busy : undefined}>Cancel</Button><Button variant="primary" disabled={busy || !valid} disabledReason={busy ? APPROVALS_I18N.busy : !valid ? APPROVALS_I18N.incomplete : undefined} onClick={() => void save()}>{busy ? "Creating" : "Create request"}</Button></>}>
    <div className="approval-editor">
      <div className="approval-editor-help"><DocumentationHelpLink reference={APPROVALS_FIELD_DOCUMENTATION} /></div>
      {error && <DismissibleAlert tone="danger" resetKey={error}>{error}</DismissibleAlert>}
      <div className="approval-editor-grid">
        <FormField label="Title" documentation={APPROVALS_FIELD_DOCUMENTATION}><input value={draft.title} disabled={busy} onChange={(event) => setDraft({ ...draft, title: event.target.value })} /></FormField>
        <FormField label="Subject module" documentation={APPROVALS_FIELD_DOCUMENTATION}><input value={draft.subject_module} disabled={busy} onChange={(event) => setDraft({ ...draft, subject_module: event.target.value })} /></FormField>
        <FormField label="Subject type" documentation={APPROVALS_FIELD_DOCUMENTATION}><input value={draft.subject_type} disabled={busy} onChange={(event) => setDraft({ ...draft, subject_type: event.target.value })} /></FormField>
        <FormField label="Subject ID" documentation={APPROVALS_FIELD_DOCUMENTATION}><input value={draft.subject_id} disabled={busy} onChange={(event) => setDraft({ ...draft, subject_id: event.target.value })} /></FormField>
        <FormField label="Subject version" documentation={APPROVALS_FIELD_DOCUMENTATION}><input value={draft.subject_version ?? ""} disabled={busy} onChange={(event) => setDraft({ ...draft, subject_version: event.target.value })} /></FormField>
        <FormField label="Subject SHA-256" documentation={APPROVALS_FIELD_DOCUMENTATION}><input value={draft.subject_digest} disabled={busy} maxLength={64} spellCheck={false} onChange={(event) => setDraft({ ...draft, subject_digest: event.target.value.trim().toLowerCase() })} /></FormField>
        <FormField label="Description" className="approval-editor-wide"><textarea rows={3} value={draft.description ?? ""} disabled={busy} onChange={(event) => setDraft({ ...draft, description: event.target.value })} /></FormField>
        <ToggleSwitch label="Separate requester and approver" checked={draft.separation_of_duties} disabled={busy} onChange={(value) => setDraft({ ...draft, separation_of_duties: value })} />
        <ToggleSwitch label="Different actor for every step" checked={draft.unique_actors_across_steps} disabled={busy} onChange={(value) => setDraft({ ...draft, unique_actors_across_steps: value })} />
      </div>
      <ApprovalStepsEditor steps={draft.steps} disabled={busy} onChange={(steps) => setDraft({ ...draft, steps })} />
    </div>
  </Dialog>;
}

function initialDraft(): ApprovalDraft {
  return { title: "", description: "", subject_module: "", subject_type: "", subject_id: "", subject_version: "", subject_digest: "", steps: [emptyApprovalStep(1)], separation_of_duties: true, unique_actors_across_steps: false, expires_at: null, policy_refs: [], evidence_actors: {}, template_id: null, template_revision: null, metadata: {} };
}

function draftKey(draft: ApprovalDraft): string {
  return JSON.stringify(draft);
}