/**
 * ActionForm — structured form editor for a single ``action.d/*.conf`` file.
 *
 * Displays parsed fields grouped into collapsible sections:
 * - Includes (before / after)
 * - Lifecycle commands (actionstart, actionstop, actioncheck, actionban,
 *   actionunban, actionflush)
 * - Definition variables (extra [Definition] key-value pairs)
 * - Init variables ([Init] section key-value pairs)
 *
 * Provides a Save button and shows saving/error state.
 */

import { useEffect, useMemo, useState } from "react";
import {
  Accordion,
  AccordionHeader,
  AccordionItem,
  AccordionPanel,
  Button,
  Field,
  Input,
  MessageBar,
  MessageBarBody,
  Skeleton,
  SkeletonItem,
  Text,
  Textarea,
} from "@fluentui/react-components";
import { Add24Regular, Delete24Regular } from "@fluentui/react-icons";
import type { ActionConfig, ActionConfigUpdate } from "../../types/config";
import { useActionConfig } from "../../hooks/useActionConfig";
import { useAutoSave } from "../../hooks/useAutoSave";
import { AutoSaveIndicator } from "./AutoSaveIndicator";
import { useConfigStyles } from "./configStyles";

// ---------------------------------------------------------------------------
// Internal helpers
// ---------------------------------------------------------------------------

/** Editable key-value table for definition_vars / init_vars. */
interface KVEditorProps {
  entries: Record<string, string>;
  onChange: (next: Record<string, string>) => void;
}

function KVEditor({ entries, onChange }: KVEditorProps): React.JSX.Element {
  const styles = useConfigStyles();
  const rows = Object.entries(entries);

  const handleKeyChange = (oldKey: string, newKey: string): void => {
    const next: Record<string, string> = {};
    for (const [k, v] of Object.entries(entries)) {
      next[k === oldKey ? newKey : k] = v;
    }
    onChange(next);
  };

  const handleValueChange = (key: string, value: string): void => {
    onChange({ ...entries, [key]: value });
  };

  const handleDelete = (key: string): void => {
    const { [key]: _removed, ...rest } = entries;
    onChange(rest);
  };

  const handleAdd = (): void => {
    let newKey = "new_var";
    let n = 1;
    while (newKey in entries) {
      newKey = `new_var_${String(n)}`;
      n++;
    }
    onChange({ ...entries, [newKey]: "" });
  };

  return (
    <div>
      {rows.map(([key, value]) => (
        <div key={key} className={styles.fieldRow}>
          <Input
            value={key}
            size="small"
            style={{ width: 160, fontFamily: "monospace" }}
            aria-label={`Variable name: ${key}`}
            onChange={(_e, d) => { handleKeyChange(key, d.value); }}
          />
          <Textarea
            value={value}
            size="small"
            style={{ flex: 1, fontFamily: "monospace" }}
            rows={value.includes("\n") ? 3 : 1}
            aria-label={`Value for ${key}`}
            onChange={(_e, d) => { handleValueChange(key, d.value); }}
          />
          <Button
            icon={<Delete24Regular />}
            size="small"
            appearance="subtle"
            onClick={() => { handleDelete(key); }}
            aria-label={`Delete variable ${key}`}
          />
        </div>
      ))}
      <Button
        icon={<Add24Regular />}
        size="small"
        appearance="outline"
        onClick={handleAdd}
        style={{ marginTop: 4 }}
      >
        Add variable
      </Button>
    </div>
  );
}

/** A Textarea field for a single lifecycle command. */
interface CommandFieldProps {
  label: string;
  value: string;
  onChange: (v: string) => void;
}

function CommandField({ label, value, onChange }: CommandFieldProps): React.JSX.Element {
  return (
    <Field label={label}>
      <Textarea
        value={value}
        onChange={(_e, d) => { onChange(d.value); }}
        rows={value.split("\n").length + 1}
        style={{ fontFamily: "monospace", width: "100%" }}
        placeholder={`${label} command(s)`}
      />
    </Field>
  );
}

// ---------------------------------------------------------------------------
// ActionFormEditor
// ---------------------------------------------------------------------------

interface ActionFormEditorProps {
  config: ActionConfig;
  onSave: (update: ActionConfigUpdate) => Promise<void>;
}

function ActionFormEditor({
  config,
  onSave,
}: ActionFormEditorProps): React.JSX.Element {
  const styles = useConfigStyles();

  const [before, setBefore] = useState(config.before ?? "");
  const [after, setAfter] = useState(config.after ?? "");
  const [actionstart, setActionstart] = useState(config.actionstart ?? "");
  const [actionstop, setActionstop] = useState(config.actionstop ?? "");
  const [actioncheck, setActioncheck] = useState(config.actioncheck ?? "");
  const [actionban, setActionban] = useState(config.actionban ?? "");
  const [actionunban, setActionunban] = useState(config.actionunban ?? "");
  const [actionflush, setActionflush] = useState(config.actionflush ?? "");
  const [definitionVars, setDefinitionVars] = useState<Record<string, string>>(
    config.definition_vars
  );
  const [initVars, setInitVars] = useState<Record<string, string>>(config.init_vars);

  // Reset draft when config reloads.
  useEffect(() => {
    setBefore(config.before ?? "");
    setAfter(config.after ?? "");
    setActionstart(config.actionstart ?? "");
    setActionstop(config.actionstop ?? "");
    setActioncheck(config.actioncheck ?? "");
    setActionban(config.actionban ?? "");
    setActionunban(config.actionunban ?? "");
    setActionflush(config.actionflush ?? "");
    setDefinitionVars(config.definition_vars);
    setInitVars(config.init_vars);
  }, [config]);

  const autoSavePayload = useMemo<ActionConfigUpdate>(() => ({
    before: before.trim() || null,
    after: after.trim() || null,
    actionstart: actionstart.trim() || null,
    actionstop: actionstop.trim() || null,
    actioncheck: actioncheck.trim() || null,
    actionban: actionban.trim() || null,
    actionunban: actionunban.trim() || null,
    actionflush: actionflush.trim() || null,
    definition_vars: definitionVars,
    init_vars: initVars,
  }), [
    after, actionban, actioncheck, actionflush, actionstart,
    actionstop, actionunban, before, definitionVars, initVars,
  ]);

  const { status: saveStatus, errorText: saveErrorText, retry: retrySave } =
    useAutoSave(autoSavePayload, onSave);

  const defVarCount = Object.keys(definitionVars).length;
  const initVarCount = Object.keys(initVars).length;

  return (
    <div>
      <div className={styles.buttonRow} style={{ marginBottom: 8 }}>
        <Text size={500} weight="semibold">
          {config.filename}
        </Text>
        <AutoSaveIndicator
          status={saveStatus}
          errorText={saveErrorText}
          onRetry={retrySave}
        />
      </div>

      <Accordion multiple collapsible defaultOpenItems={["lifecycle"]}>
        {/* Includes */}
        <AccordionItem value="includes" className={styles.accordionItem}>
          <AccordionHeader>Includes</AccordionHeader>
          <AccordionPanel>
            <div className={styles.sectionCard}>
              <Field label="before">
                <Input
                  value={before}
                  onChange={(_e, d) => { setBefore(d.value); }}
                  placeholder="e.g. iptables-common.conf"
                  className={styles.codeInput}
                />
              </Field>
              <Field label="after">
                <Input
                  value={after}
                  onChange={(_e, d) => { setAfter(d.value); }}
                  className={styles.codeInput}
                />
              </Field>
            </div>
          </AccordionPanel>
        </AccordionItem>

        {/* Lifecycle commands */}
        <AccordionItem value="lifecycle" className={styles.accordionItem}>
          <AccordionHeader>Lifecycle commands</AccordionHeader>
          <AccordionPanel>
            <div className={styles.sectionCard}>
              <CommandField label="actionstart" value={actionstart} onChange={setActionstart} />
              <CommandField label="actionstop" value={actionstop} onChange={setActionstop} />
              <CommandField label="actioncheck" value={actioncheck} onChange={setActioncheck} />
              <CommandField label="actionban" value={actionban} onChange={setActionban} />
              <CommandField label="actionunban" value={actionunban} onChange={setActionunban} />
              <CommandField label="actionflush" value={actionflush} onChange={setActionflush} />
            </div>
          </AccordionPanel>
        </AccordionItem>

        {/* Definition variables */}
        <AccordionItem value="definition_vars" className={styles.accordionItem}>
          <AccordionHeader>
            {`Definition variables (${String(defVarCount)})`}
          </AccordionHeader>
          <AccordionPanel>
            <div className={styles.sectionCard}>
              <KVEditor entries={definitionVars} onChange={setDefinitionVars} />
            </div>
          </AccordionPanel>
        </AccordionItem>

        {/* Init variables */}
        <AccordionItem value="init_vars" className={styles.accordionItem}>
          <AccordionHeader>
            {`Init variables (${String(initVarCount)})`}
          </AccordionHeader>
          <AccordionPanel>
            <div className={styles.sectionCard}>
              <KVEditor entries={initVars} onChange={setInitVars} />
            </div>
          </AccordionPanel>
        </AccordionItem>
      </Accordion>
    </div>
  );
}

// ---------------------------------------------------------------------------
// ActionForm (public export)
// ---------------------------------------------------------------------------

export interface ActionFormProps {
  /** Action base name (e.g. ``"iptables"``). */
  name: string;
}

/**
 * Loads and renders the structured form editor for one action.
 */
export function ActionForm({ name }: ActionFormProps): React.JSX.Element {
  const { config, loading, error, save } = useActionConfig(name);

  if (loading) {
    return (
      <Skeleton aria-label={`Loading ${name}…`}>
        <div style={{ display: "grid", gridTemplateColumns: "1fr 1fr", gap: 8, marginBottom: 8 }}>
          <SkeletonItem size={32} />
          <SkeletonItem size={32} />
        </div>
        <SkeletonItem size={72} style={{ marginBottom: 8 }} />
        <SkeletonItem size={72} />
      </Skeleton>
    );
  }

  if (error !== null || config === null) {
    return (
      <MessageBar intent="error">
        <MessageBarBody>{error ?? "Failed to load action config"}</MessageBarBody>
      </MessageBar>
    );
  }

  return (
    <ActionFormEditor
      config={config}
      onSave={save}
    />
  );
}