/**
 * Database tools state: data sources, connection status, the introspection
 * cache of the tree, query consoles (file → data source) and their results.
 */
import { create } from "zustand";
import {
  IpcError,
  call,
  commands,
  isCancelled,
  nextRequestId,
  type DataSource,
  type DbCompletion,
  type DbDatabases,
  type DbDriver,
  type DbObjectKind,
  type DbPlanNode,
  type DbSchemaObjects,
  type DbStatementOutcome,
  type DbTableDetails,
  type DbTableInfo,
  type DbTableKind,
  type RequestId,
  type SqlStatement,
} from "@/platform/ipc";
import { editorsFor } from "@/editor/api";
import {
  editorService,
  notifications,
  showServiceView,
  toolWindowService,
  type FileDecoration,
} from "@/workbench/contributions";
import { workflowSettings } from "@/platform/workflowSettings";
import { ask, confirm } from "@/workbench/messages";
import { colorVar, connectRemedy, databaseKey, effectiveSsh, idleTargets, newSourceId, splitTarget } from "./model";
import { tableFolder, type DbNode } from "./nodes";
import type { ExportData, ExportFormat } from "./export";
import type { DbObjectRef } from "./objects";
import { formatted } from "./sql/format";
import { bindParams, findParams } from "./sql/params";
import { tx } from "@/platform/i18n";

export const DB_TOOL_WINDOW = "database";
export const RESULTS_VIEW = "dbResults";
const BINDINGS_KEY = "openidea.database.consoles";
const MAX_TABS = 12;

export interface ResultTab {
  id: number;
  /** `Result N` (numbered per window, like IDEA). */
  title: string;
  /** Console file the statement came from. */
  path: string;
  sourceId: string;
  outcome: DbStatementOutcome;
  /** The Query Plan tab: the plan of `outcome.statement` (which was explained, not run). */
  plan?: DbPlanNode[];
  /** Being re-run. */
  busy?: boolean;
}

/** One line of the consoles' Output log (IDEA's Database Console output). */
export interface OutputLine {
  id: number;
  time: number;
  kind: "info" | "statement" | "result" | "error";
  text: string;
  /** Prompt before a statement: the schema it ran in (`main>`). */
  prompt?: string;
}

/** `activeResult` value of the Output tab. */
export const OUTPUT_TAB = 0;
const MAX_OUTPUT = 2000;

/** Load state of a tree level. */
export type Loaded<T> = { status: "loading" } | { status: "error"; message: string } | { status: "ok"; value: T };

export type DialogState =
  /** Data source properties; `preset` seeds a new one (New › Data Source › PostgreSQL). */
  | { kind: "source"; source: DataSource | null; preset?: Partial<DataSource>; password?: string | null }
  /** Data Source from URL. */
  | { kind: "sourceUrl" }
  /** Rename a data source (`object` null) or a schema object of target `id`. */
  | { kind: "rename"; id: string; object: DbObjectRef | null }
  /** Confirm Drop / Truncate, with a preview of the statement. */
  | { kind: "drop"; id: string; object: DbObjectRef }
  | { kind: "truncate"; id: string; schema: string; table: string }
  /** Modify Table (`table` null: New › Table); `focusColumn` selects a column, `addColumn` starts a new one. */
  | { kind: "modifyTable"; id: string; schema: string; table: string | null; focusColumn?: string; addColumn?: boolean }
  /** Quick Documentation of a tree node, shown at `anchor` (client coordinates). */
  | { kind: "quickDoc"; node: DbNode; anchor: { x: number; y: number } }
  | { kind: "password"; source: DataSource; resolve: (ok: boolean) => void }
  /** SSH password or key passphrase (`prompt` is the backend's reason). */
  | { kind: "sshSecret"; source: DataSource; prompt: string; resolve: (ok: boolean) => void }
  /** Values of query parameters (`null`: cancelled). */
  | { kind: "params"; names: string[]; resolve: (values: Record<string, string> | null) => void }
  /** Export Data of a result or table page; `source` names it (`main.customers`). */
  | { kind: "export"; data: ExportData; source: string; format?: ExportFormat }
  /** Browse Query History of target `id`; Paste goes to console `path`. */
  | { kind: "history"; id: string; path: string | null }
  /** Import Data from File into a table. */
  | { kind: "import"; id: string; schema: string; table: string };

interface DatabaseState {
  sources: DataSource[];
  loaded: boolean;
  /** Connected targets (see `splitTarget`). */
  connected: Set<string>;
  /** Data source id → databases of its server (PostgreSQL). */
  databases: Record<string, Loaded<DbDatabases>>;
  /** Target → schemas. */
  schemas: Record<string, Loaded<string[]>>;
  /** `${id}\u0000${schema}` → tables. */
  tables: Record<string, Loaded<DbTableInfo[]>>;
  /** `${id}\u0000${schema}\u0000${table}` → columns / indexes. */
  details: Record<string, Loaded<DbTableDetails>>;
  /** `${id}\u0000${schema}` → routines and sequences (loaded with the tables). */
  objects: Record<string, DbSchemaObjects>;
  /** Console / SQL file path → data source id. */
  consoles: Record<string, string>;
  completion: Record<string, DbCompletion>;
  results: ResultTab[];
  /** Result tab id, or `OUTPUT_TAB`. */
  activeResult: number | null;
  output: OutputLine[];
  /** Console path → running request. */
  running: Record<string, RequestId>;
  maxRows: number;
  dialog: DialogState | null;
  /** Target of the tree's lead node. */
  selectedSource: string | null;
  /** The tree's lead node: what the tree actions act on. */
  selectedNode: DbNode | null;
  /** The toolbar's New popup is open. */
  newMenuOpen: boolean;
  /** Expanded nodes of the Database tree. */
  treeExpanded: Set<string>;
  /** A tree node to select and scroll to (Go to Declaration from a console). */
  treeReveal: { key: string; seq: number } | null;
  /** Last value entered per query parameter name. */
  paramValues: Record<string, string>;
  /** Data sources in manual-commit mode. */
  manualCommit: Set<string>;
  /** Manual-commit data sources with statements not yet committed. */
  pendingTx: Set<string>;
}

function readBindings(): Record<string, string> {
  try {
    const raw = localStorage.getItem(BINDINGS_KEY);
    return raw ? (JSON.parse(raw) as Record<string, string>) : {};
  } catch {
    return {};
  }
}

export const useDatabase = create<DatabaseState>(() => ({
  sources: [],
  loaded: false,
  connected: new Set(),
  databases: {},
  schemas: {},
  tables: {},
  details: {},
  objects: {},
  consoles: readBindings(),
  completion: {},
  results: [],
  activeResult: null,
  output: [],
  running: {},
  maxRows: 500,
  dialog: null,
  selectedSource: null,
  selectedNode: null,
  newMenuOpen: false,
  treeExpanded: new Set(),
  treeReveal: null,
  paramValues: {},
  manualCommit: new Set(),
  pendingTx: new Set(),
}));

export const tablesKey = (id: string, schema: string) => `${id}\u0000${schema}`;
export const detailsKey = (id: string, schema: string, table: string) => `${id}\u0000${schema}\u0000${table}`;

function message(e: unknown): string {
  return e instanceof Error ? e.message : String(e);
}

/** The data source of a target (`<id>` or `<id>:<database>`). */
export function sourceById(id: string | null | undefined): DataSource | undefined {
  if (!id) return undefined;
  const sourceId = splitTarget(id).id;
  return useDatabase.getState().sources.find((s) => s.id === sourceId);
}

/** `name` or `name: database` for messages and pickers. */
export function targetLabel(target: string): string {
  const name = sourceById(target)?.name ?? target;
  const db = splitTarget(target).database;
  return db ? `${name}: ${db}` : name;
}

/** Targets of data source `id` that are connected. */
export function connectedTargets(id: string): string[] {
  return [...useDatabase.getState().connected].filter((t) => splitTarget(t).id === id);
}

export async function loadSources(): Promise<void> {
  try {
    const [sources, connected] = await Promise.all([call(commands.dbSources()), call(commands.dbConnected())]);
    useDatabase.setState({ sources, connected: new Set(connected), loaded: true });
  } catch (e) {
    useDatabase.setState({ loaded: true });
    notifications().notify({ level: "error", title: "Cannot read data sources", body: message(e), key: "db-sources" });
  }
}

/** Drops cached metadata of target `id` (refresh, disconnect); a data source id drops all its databases. */
function forget(id: string) {
  const whole = !splitTarget(id).database;
  const ofTarget = (t: string) => t === id || (whole && splitTarget(t).id === id);
  const dropKeys = <T>(m: Record<string, T>) =>
    Object.fromEntries(Object.entries(m).filter(([k]) => !ofTarget(k.split("\u0000")[0]!)));
  useDatabase.setState((s) => {
    const databases = { ...s.databases };
    if (whole) delete databases[id];
    return {
      databases,
      schemas: dropKeys(s.schemas),
      completion: dropKeys(s.completion),
      tables: dropKeys(s.tables),
      details: dropKeys(s.details),
      objects: dropKeys(s.objects),
    };
  });
}

export async function saveSource(
  source: DataSource,
  password: string | null | undefined,
  sshSecret: string | null | undefined = undefined,
): Promise<void> {
  const sources = useDatabase.getState().sources;
  const next = sources.some((s) => s.id === source.id)
    ? sources.map((s) => (s.id === source.id ? source : s))
    : [...sources, source];
  await call(commands.dbSaveSources(next));
  // `undefined`: keep; `null`: forget; string: store.
  const id = source.id ?? "";
  if (password !== undefined) await call(commands.dbSetPassword(id, password, !!source.savePassword));
  if (sshSecret !== undefined) await call(commands.dbSetSshSecret(id, sshSecret, !!source.ssh?.saveSecret));
  forget(id);
  await loadSources();
}

/** Copy/Paste › Duplicate: a copy of data source `id` named `<name> [2]` (its password is not copied). */
export async function duplicateSource(id: string): Promise<void> {
  const src = sourceById(id);
  if (!src) return;
  const names = new Set(useDatabase.getState().sources.map((s) => s.name));
  let n = 2;
  while (names.has(`${src.name} [${n}]`)) n++;
  try {
    await saveSource({ ...src, id: newSourceId(), name: `${src.name} [${n}]` }, undefined);
  } catch (e) {
    notifications().notify({ level: "error", title: "Cannot duplicate the data source", body: message(e) });
  }
}

export async function renameSource(id: string, name: string): Promise<void> {
  const src = sourceById(id);
  if (!src || !name.trim() || name.trim() === src.name) return;
  const sources = useDatabase.getState().sources.map((s) => (s.id === src.id ? { ...s, name: name.trim() } : s));
  await call(commands.dbSaveSources(sources));
  await loadSources();
}

/** Removes the data source after asking (Database tree › Drop on a source). */
export async function removeSource(source: DataSource): Promise<void> {
  const ok = await confirm({
    title: "Remove Data Source",
    message: tx`Remove data source '${source.name}'? Its query console file stays on disk.`,
    ok: "Remove",
  });
  if (!ok) return;
  const id = source.id ?? "";
  if (connectedTargets(id).length) await disconnect(id);
  await deleteSource(id);
}

export async function deleteSource(id: string): Promise<void> {
  await call(commands.dbSaveSources(useDatabase.getState().sources.filter((s) => s.id !== id)));
  forget(id);
  await loadSources();
}

export function openSourceDialog(source: DataSource | null, preset?: Partial<DataSource>, password?: string | null) {
  useDatabase.setState({ dialog: { kind: "source", source, preset, password } });
}

export function openDialog(dialog: DialogState) {
  useDatabase.setState({ dialog });
}

export function closeDialog() {
  useDatabase.setState({ dialog: null });
}

/** Asks for the password of `source` (ask-on-connect); resolves false when cancelled. */
function askPassword(source: DataSource): Promise<boolean> {
  return new Promise((resolve) => useDatabase.setState({ dialog: { kind: "password", source, resolve } }));
}

function askSshSecret(source: DataSource, prompt: string): Promise<boolean> {
  return new Promise((resolve) => useDatabase.setState({ dialog: { kind: "sshSecret", source, prompt, resolve } }));
}

/** First connection to an SSH host: trust its key (added to ~/.ssh/known_hosts)? */
function askTrustHost(prompt: string): Promise<boolean> {
  return confirm({
    title: "Unknown SSH Host",
    icon: "warning",
    message: `${prompt}. The authenticity of the host cannot be established. Trust it and add the key to ~/.ssh/known_hosts?`,
    ok: "Trust and Connect",
  });
}

/** Asks the user what a failed connection needs (password, SSH secret, host key trust); false = give up. */
export async function resolveConnectError(e: unknown, source: DataSource): Promise<boolean> {
  if (!(e instanceof IpcError)) return false;
  // Prompts show the SSH configuration's host and authentication when the tunnel uses one.
  const resolved = { ...source, ssh: effectiveSsh(source.ssh, workflowSettings().ssh.configs) };
  switch (connectRemedy(e.kind, e.message, resolved)) {
    case "password":
      return askPassword(source);
    case "sshSecret":
      return askSshSecret(resolved, e.message);
    case "trustHostKey":
      if (!(await askTrustHost(e.message))) return false;
      await call(commands.dbTrustSshHost(source.id ?? ""));
      return true;
    default:
      return false;
  }
}

/** Target → time of its last use (Options › Auto-disconnect). */
const lastUsed = new Map<string, number>();

/** Options › Transaction control: a manual data source's consoles start in manual commit. */
function applyConnectDefaults(id: string) {
  if (sourceById(id)?.options?.transaction === "manual" && !useDatabase.getState().manualCommit.has(id))
    void setManualCommit(id, true).catch(() => {});
}

/** Runs `op`, asking for passwords / host key trust and retrying when the connection needs them. */
export async function withConnection<T>(id: string, op: () => Promise<T>): Promise<T> {
  for (;;) {
    try {
      const r = await op();
      lastUsed.set(id, Date.now());
      if (!useDatabase.getState().connected.has(id)) {
        useDatabase.setState((s) => ({ connected: new Set(s.connected).add(id) }));
        applyConnectDefaults(id);
      }
      return r;
    } catch (e) {
      const source = sourceById(id);
      if (!source || !(await resolveConnectError(e, source))) throw e;
    }
  }
}

export async function connect(id: string): Promise<boolean> {
  try {
    await withConnection(id, () => call(commands.dbConnect(id)));
    return true;
  } catch (e) {
    if (!isCancelled(e))
      notifications().notify({ level: "error", title: `Cannot connect to ${targetLabel(id)}`, body: message(e) });
    return false;
  }
}

/** Disconnects target `id`; a data source id disconnects all its databases. */
export async function disconnect(id: string): Promise<void> {
  const targets = splitTarget(id).database ? [id] : connectedTargets(id);
  if (!targets.includes(id)) targets.push(id);
  await Promise.all(targets.map((t) => call(commands.dbDisconnect(t))));
  forget(id);
  useDatabase.setState((s) => {
    const connected = new Set(s.connected);
    for (const t of targets) connected.delete(t);
    return { connected };
  });
}

/** Disconnects targets idle past their data source's Auto-disconnect; returns the stopper. */
export function watchIdleConnections(everyMs = 5000): () => void {
  const timer = setInterval(() => {
    const s = useDatabase.getState();
    const running = new Set(Object.keys(s.running).map((path) => s.consoles[path]));
    const busy = (t: string) => running.has(t) || s.pendingTx.has(t);
    for (const t of idleTargets(s.connected, s.sources, lastUsed, busy, Date.now())) {
      lastUsed.delete(t);
      void disconnect(t).then(() => log("info", `${targetLabel(t)}: disconnected after being idle`));
    }
  }, everyMs);
  return () => clearInterval(timer);
}

/** Console files of coloured data sources, tinted like IDEA's (file decorations). */
export function consoleTints(s: Pick<DatabaseState, "consoles" | "sources">): Map<string, FileDecoration> {
  const out = new Map<string, FileDecoration>();
  for (const [path, target] of Object.entries(s.consoles)) {
    const id = splitTarget(target).id;
    const tint = colorVar(s.sources.find((x) => x.id === id)?.color);
    if (tint) out.set(path, { tint });
  }
  return out;
}

/** PostgreSQL data sources show their server's databases (IDEA's data source › database › schema). */
export function listsDatabases(source: DataSource | undefined): boolean {
  return source?.driver === "postgres" && !source.options?.singleDatabase;
}

/**
 * Re-reads the metadata of target `id` (a data source id: all its databases),
 * reloading the levels that were loaded so the tree keeps its expanded nodes.
 */
export async function refresh(id: string): Promise<void> {
  const whole = !splitTarget(id).database;
  const ofTarget = (k: string) => {
    const t = k.split("\u0000")[0]!;
    return t === id || (whole && splitTarget(t).id === id);
  };
  const st = useDatabase.getState();
  const loaded = (m: Record<string, Loaded<unknown>>) =>
    Object.keys(m).filter((k) => ofTarget(k) && m[k]!.status === "ok");
  const schemas = loaded(st.schemas);
  const tables = loaded(st.tables).map((k) => k.split("\u0000") as [string, string]);
  const details = loaded(st.details).map((k) => k.split("\u0000") as [string, string, string]);
  forget(id);
  if (whole && listsDatabases(sourceById(id))) await loadDatabases(id);
  else if (!schemas.includes(id)) schemas.push(id);
  await Promise.all(schemas.map((t) => loadSchemas(t)));
  await Promise.all(tables.map(([t, schema]) => loadTables(t, schema)));
  const exists = (t: string, schema: string, table: string) => {
    const l = useDatabase.getState().tables[tablesKey(t, schema)];
    return l?.status === "ok" && l.value.some((x) => x.name === table);
  };
  await Promise.all(details.filter((d) => exists(...d)).map(([t, schema, table]) => loadDetails(t, schema, table)));
}

export async function loadDatabases(id: string): Promise<void> {
  useDatabase.setState((s) => ({ databases: { ...s.databases, [id]: { status: "loading" } } }));
  try {
    const value = await withConnection(id, () => call(commands.dbDatabases(id)));
    useDatabase.setState((s) => ({ databases: { ...s.databases, [id]: { status: "ok", value } } }));
  } catch (e) {
    useDatabase.setState((s) => ({ databases: { ...s.databases, [id]: { status: "error", message: message(e) } } }));
  }
}

export async function loadSchemas(id: string): Promise<void> {
  useDatabase.setState((s) => ({ schemas: { ...s.schemas, [id]: { status: "loading" } } }));
  try {
    const value = await withConnection(id, () => call(commands.dbSchemas(id)));
    useDatabase.setState((s) => ({ schemas: { ...s.schemas, [id]: { status: "ok", value } } }));
  } catch (e) {
    useDatabase.setState((s) => ({ schemas: { ...s.schemas, [id]: { status: "error", message: message(e) } } }));
  }
}

export async function loadTables(id: string, schema: string): Promise<void> {
  const key = tablesKey(id, schema);
  useDatabase.setState((s) => ({ tables: { ...s.tables, [key]: { status: "loading" } } }));
  try {
    const value = await withConnection(id, () => call(commands.dbTables(id, schema)));
    // Routines / sequences are extras: a server refusing their catalog still lists tables.
    const objects = await call(commands.dbSchemaObjects(id, schema)).catch(() => null);
    useDatabase.setState((s) => ({
      tables: { ...s.tables, [key]: { status: "ok", value } },
      objects: objects ? { ...s.objects, [key]: objects } : s.objects,
    }));
  } catch (e) {
    useDatabase.setState((s) => ({ tables: { ...s.tables, [key]: { status: "error", message: message(e) } } }));
  }
}

export async function loadDetails(id: string, schema: string, table: string): Promise<void> {
  const key = detailsKey(id, schema, table);
  useDatabase.setState((s) => ({ details: { ...s.details, [key]: { status: "loading" } } }));
  try {
    const value = await withConnection(id, () => call(commands.dbTableDetails(id, schema, table)));
    useDatabase.setState((s) => ({ details: { ...s.details, [key]: { status: "ok", value } } }));
  } catch (e) {
    useDatabase.setState((s) => ({ details: { ...s.details, [key]: { status: "error", message: message(e) } } }));
  }
}

/**
 * Selects a table (or one of its columns) in the Database tool window,
 * loading and expanding the nodes that lead to it.
 */
export async function revealInTree(
  id: string,
  schema: string,
  table: string,
  kind: DbTableKind,
  column?: string,
): Promise<void> {
  const loaded = (l: Loaded<unknown> | undefined) => l?.status === "ok";
  const { id: sourceId, database } = splitTarget(id);
  let databaseNode: string[] = [];
  if (listsDatabases(sourceById(id))) {
    if (!loaded(useDatabase.getState().databases[sourceId])) {
      if (!(await connect(sourceId))) return;
      await loadDatabases(sourceId);
    }
    const dbs = useDatabase.getState().databases[sourceId];
    const name = database ?? (dbs?.status === "ok" ? dbs.value.current : null);
    if (name) databaseNode = [databaseKey(sourceId, name)];
  }
  if (!loaded(useDatabase.getState().schemas[id])) {
    if (!(await connect(id))) return;
    await loadSchemas(id);
  }
  if (!loaded(useDatabase.getState().tables[tablesKey(id, schema)])) await loadTables(id, schema);
  if (column && !loaded(useDatabase.getState().details[detailsKey(id, schema, table)]))
    await loadDetails(id, schema, table);
  const folder = `${id}/${schema}/${tableFolder(kind)}`;
  const tableKey = `${folder}/${table}`;
  const open = [
    sourceId,
    ...databaseNode,
    `${id}/${schema}`,
    folder,
    ...(column ? [tableKey, `${tableKey}/columns`] : []),
  ];
  useDatabase.setState((s) => ({
    treeExpanded: new Set([...s.treeExpanded, ...open]),
    treeReveal: { key: column ? `${tableKey}/columns/${column}` : tableKey, seq: (s.treeReveal?.seq ?? 0) + 1 },
  }));
  toolWindowService().show(DB_TOOL_WINDOW, true);
}

const completionLoads = new Map<string, Promise<DbCompletion | null>>();

/** The schema model of `id` for completion (cached; one load at a time). */
export function loadCompletion(id: string): Promise<DbCompletion | null> {
  const cached = useDatabase.getState().completion[id];
  if (cached) return Promise.resolve(cached);
  let p = completionLoads.get(id);
  if (!p) {
    p = call(commands.dbCompletion(id))
      .then((model) => {
        useDatabase.setState((s) => ({ completion: { ...s.completion, [id]: model } }));
        return model;
      })
      .catch(() => null)
      .finally(() => completionLoads.delete(id));
    completionLoads.set(id, p);
  }
  return p;
}

// ---- consoles ----------------------------------------------------------------

export function bindConsole(path: string, id: string | null) {
  useDatabase.setState((s) => {
    const consoles = { ...s.consoles };
    if (id) consoles[path] = id;
    else delete consoles[path];
    try {
      localStorage.setItem(BINDINGS_KEY, JSON.stringify(consoles));
    } catch {
      // Per-viewer convenience only.
    }
    return { consoles };
  });
}

/** The data source a console / SQL file runs on: its binding, else the only data source. */
export function consoleSource(path: string): string | null {
  const s = useDatabase.getState();
  const bound = s.consoles[path];
  if (bound && s.sources.some((x) => x.id === splitTarget(bound).id)) return bound;
  return s.sources.length === 1 ? (s.sources[0]!.id ?? null) : null;
}

/** Opens (creating it on first use) the query console of data source `id`. */
export async function openConsole(id: string): Promise<void> {
  try {
    const path = await call(commands.dbConsolePath(id));
    bindConsole(path, id);
    await editorService().openFile(path, { focus: true });
  } catch (e) {
    notifications().notify({ level: "error", title: "Cannot open the query console", body: message(e) });
  }
}

let nextTab = 1;
let nextLine = 1;

export function log(kind: OutputLine["kind"], text: string, prompt?: string) {
  const line: OutputLine = { id: nextLine++, time: Date.now(), kind, text, prompt };
  useDatabase.setState((s) => ({ output: [...s.output, line].slice(-MAX_OUTPUT) }));
}

export function clearOutput() {
  useDatabase.setState({ output: [] });
}

function elapsed(ms: number): string {
  return ms < 1000 ? `${Math.round(ms)} ms` : `${(ms / 1000).toFixed(1)} s`;
}

/** IDEA's summary line of an executed statement. */
export function outcomeSummary(o: DbStatementOutcome): string {
  const r = o.result;
  if (!r) return o.error ?? "";
  const n = r.columns.length ? r.rows.length : (r.affected ?? 0);
  const rows = `${n} row${n === 1 ? "" : "s"}`;
  if (!r.columns.length) return `${rows} affected in ${elapsed(r.elapsedMs ?? 0)}`;
  const total = r.elapsedMs ?? 0;
  const execution = Math.min(total, r.executionMs ?? total);
  const split = ` (execution: ${elapsed(execution)}, fetching: ${elapsed(total - execution)})`;
  return `${rows} retrieved starting from 1 in ${elapsed(total)}${split}${r.hasMore ? " (limit reached)" : ""}`;
}

/** The schema shown as the Output prompt (`main>`). */
function promptOf(id: string): string {
  return useDatabase.getState().completion[id]?.defaultSchema || sourceById(id)?.name || id;
}

/** Runs `statements` on `id`, logging to Output; errors stop the batch (backend). */
async function run(id: string, statements: SqlStatement[], request: RequestId): Promise<DbStatementOutcome[]> {
  const wasConnected = useDatabase.getState().connected.has(id);
  const outcomes = await withConnection(id, () =>
    call(commands.dbExecute(request, id, statements, useDatabase.getState().maxRows)),
  );
  if (!wasConnected) log("info", "Connected");
  for (const o of outcomes) {
    log("statement", o.statement.text, `${promptOf(id)}>`);
    log(o.error ? "error" : "result", o.error ? `[${targetLabel(id)}] ${o.error}` : outcomeSummary(o));
  }
  if (useDatabase.getState().manualCommit.has(id) && outcomes.some((o) => !o.error && !READS.test(o.statement.text)))
    useDatabase.setState((s) => ({ pendingTx: new Set(s.pendingTx).add(id) }));
  if (outcomes.some((o) => /^\s*(create|drop|alter|rename)\b/i.test(o.statement.text) && !o.error)) {
    // Schema changed: the tree and completion re-read it.
    void refresh(id);
  }
  return outcomes;
}

/**
 * Runs statements the tree's object actions generated (Drop, Rename, Modify
 * Table…) on `id`, logging them to Output; false (and a notification) on error.
 */
export async function runSql(id: string, texts: string[]): Promise<boolean> {
  const statements = texts.map((t) => {
    const text = t.trim().replace(/;$/, "");
    return { from: 0, to: text.length, text };
  });
  try {
    const outcomes = await run(id, statements, nextRequestId());
    const failed = outcomes.find((o) => o.error);
    if (failed) {
      notifications().notify({
        level: "error",
        title: `[${targetLabel(id)}] ${failed.statement.text}`,
        body: failed.error ?? "",
      });
      return false;
    }
    return true;
  } catch (e) {
    if (!isCancelled(e))
      notifications().notify({ level: "error", title: `Cannot execute on ${targetLabel(id)}`, body: message(e) });
    return false;
  }
}

/** Opens the query console of `id` with `text` appended and selected (SQL Scripts › …). */
export async function openConsoleWith(id: string, text: string): Promise<void> {
  let path: string;
  try {
    path = await call(commands.dbConsolePath(id));
  } catch (e) {
    notifications().notify({ level: "error", title: "Cannot open the query console", body: message(e) });
    return;
  }
  await openConsole(id);
  // The editor mounts after `openFile` resolves.
  for (let i = 0; i < 40; i++) {
    const view = editorsFor(path)[0]?.view;
    if (view) {
      const doc = view.state.doc.toString();
      const sep = !doc || doc.endsWith("\n\n") ? "" : doc.endsWith("\n") ? "\n" : "\n\n";
      const from = doc.length + sep.length;
      view.dispatch({
        changes: { from: doc.length, insert: sep + text },
        selection: { anchor: from, head: from + text.trimEnd().length },
        scrollIntoView: true,
      });
      view.focus();
      return;
    }
    await new Promise((r) => setTimeout(r, 50));
  }
}

/** DDL laid out like IDEA's: SQLite returns the statements as they were typed. */
export function readableDdl(text: string, driver: DbDriver | undefined): string {
  return driver === "sqlite" ? formatted(text, driver) : text;
}

/** Go to DDL: the definition of a table / view, in a SQL file next to the data source's console. */
export async function openDdl(id: string, schema: string, name: string): Promise<void> {
  try {
    const [text, console] = await Promise.all([
      withConnection(id, () => call(commands.dbDdl(id, schema, name))),
      call(commands.dbConsolePath(id)),
    ]);
    const safe = (s: string) => s.replace(/[^\w.-]+/g, "_");
    const path = console.replace(/[^\\/]*$/, `${safe(schema)}.${safe(name)}.sql`);
    await call(commands.dbExportFile(path, readableDdl(text, sourceById(id)?.driver)));
    bindConsole(path, id);
    await editorService().openFile(path, { focus: true });
  } catch (e) {
    notifications().notify({ level: "error", title: `Cannot get the DDL of ${name}`, body: message(e) });
  }
}

/**
 * Runs the statement at `from` (or the selection `from..to`, UTF-16 offsets)
 * of console `path` on its data source. Result sets open as `Result N` tabs
 * of the Services view, everything is logged to its Output tab; returns the
 * outcomes (errors included) for the editor's marks.
 */
/** Asks for the values of the statements' query parameters and binds them; `[]` when cancelled. */
async function withParams(statements: SqlStatement[], driver: DbDriver): Promise<SqlStatement[]> {
  let numbered = 0;
  const found = statements.map((st) => {
    const params = findParams(st.text, driver, numbered);
    numbered += params.filter((p) => p.positional).length;
    return params;
  });
  const names = [...new Set(found.flat().map((p) => p.name))];
  if (!names.length) return statements;
  const values = await new Promise<Record<string, string> | null>((resolve) =>
    useDatabase.setState({ dialog: { kind: "params", names, resolve } }),
  );
  if (!values) return [];
  useDatabase.setState((s) => ({ paramValues: { ...s.paramValues, ...values } }));
  return statements.map((st, i) => ({ ...st, text: bindParams(st.text, found[i]!, values) }));
}

export async function executeConsole(
  path: string,
  text: string,
  from: number,
  to: number,
): Promise<DbStatementOutcome[]> {
  const id = consoleSource(path);
  if (!id) {
    notifications().notify({
      level: "info",
      title: useDatabase.getState().sources.length ? "Choose a data source for this console" : "No data sources",
      body: useDatabase.getState().sources.length
        ? "Pick one in the toolbar above the editor."
        : "Add one in the Database tool window.",
      key: "db-execute",
    });
    return [];
  }
  const statements = await consoleStatements(id, text, from, to);
  if (!statements.length) return [];
  const prev = useDatabase.getState().running[path];
  if (prev) void commands.cancelRequest(prev);
  const request = nextRequestId();
  useDatabase.setState((s) => ({ running: { ...s.running, [path]: request } }));
  try {
    const outcomes = await run(id, statements, request);
    const tabs: ResultTab[] = outcomes
      .filter((o) => o.result?.columns.length)
      .map((outcome) => {
        const n = nextTab++;
        return { id: n, title: tx`Result ${n}`, path, sourceId: id, outcome };
      });
    const failed = outcomes.some((o) => o.error);
    useDatabase.setState((s) => ({
      results: [...s.results, ...tabs].slice(-MAX_TABS),
      activeResult: failed || !tabs.length ? OUTPUT_TAB : tabs.at(-1)!.id,
    }));
    showServiceView(RESULTS_VIEW, false);
    return outcomes;
  } catch (e) {
    if (!isCancelled(e)) {
      log("error", message(e));
      notifications().notify({ level: "error", title: "Cannot execute", body: message(e), key: "db-execute" });
    } else {
      log("info", "Cancelled");
      // The backend dropped the connection, and its transaction with it.
      if (useDatabase.getState().pendingTx.has(id)) {
        log("info", "Transaction rolled back");
        setPending(id, false);
      }
    }
    return [];
  } finally {
    useDatabase.setState((s) => {
      if (s.running[path] !== request) return s;
      const running = { ...s.running };
      delete running[path];
      return { running };
    });
  }
}

/** The statements of console `path` to run or explain: the selection's, else the one at `from`, parameters bound. */
async function consoleStatements(id: string, text: string, from: number, to: number): Promise<SqlStatement[]> {
  const statements: SqlStatement[] = await call(commands.dbStatements(id, text, from, to));
  if (!statements.length) return [];
  return withParams(statements, sourceById(id)?.driver ?? "sqlite");
}

const PLAN_TITLE = "Query Plan";

/** Shows `plan` of `statement` in the window's Query Plan tab (one per window, like IDEA's). */
function showPlan(path: string, id: string, statement: SqlStatement, plan: DbPlanNode[]) {
  useDatabase.setState((s) => {
    const old = s.results.find((r) => r.plan);
    const tab: ResultTab = {
      id: old?.id ?? nextTab++,
      title: PLAN_TITLE,
      path,
      sourceId: id,
      outcome: { statement, result: null, error: null },
      plan,
    };
    const results = old ? s.results.map((r) => (r === old ? tab : r)) : [...s.results, tab].slice(-MAX_TABS);
    return { results, activeResult: tab.id };
  });
  showServiceView(RESULTS_VIEW, false);
}

async function explain(id: string, statement: SqlStatement): Promise<DbPlanNode[]> {
  const plan = await withConnection(id, () => call(commands.dbExplain(nextRequestId(), id, statement.text)));
  log("statement", `explain ${statement.text}`, `${promptOf(id)}>`);
  log("result", `${plan.length} plan node${plan.length === 1 ? "" : "s"}`);
  return plan;
}

/** Explain Plan: the plan of the statement at `from` (the first selected one) of console `path`. */
export async function explainConsole(path: string, text: string, from: number, to: number): Promise<void> {
  const id = consoleSource(path);
  if (!id) return;
  try {
    const [statement] = await consoleStatements(id, text, from, to);
    if (!statement) return;
    showPlan(path, id, statement, await explain(id, statement));
  } catch (e) {
    if (isCancelled(e)) return;
    log("error", `[${targetLabel(id)}] ${message(e)}`);
    notifications().notify({
      level: "error",
      title: "Cannot explain the statement",
      body: message(e),
      key: "db-explain",
    });
  }
}

/** Browse Query History of the data source of console `path` (or of target `id`). */
export function openHistory(path: string | null, id: string | null = path ? consoleSource(path) : null) {
  if (!id) {
    notifications().notify({ level: "info", title: "Choose a data source for this console", key: "db-history" });
    return;
  }
  openDialog({ kind: "history", id, path });
}

/** Go to DDL of a routine, trigger or sequence: its definition in a SQL file next to the console. */
export async function openObjectDdl(id: string, schema: string, kind: DbObjectKind, name: string): Promise<void> {
  try {
    const [text, console] = await Promise.all([
      withConnection(id, () => call(commands.dbObjectDdl(id, schema, kind, name))),
      call(commands.dbConsolePath(id)),
    ]);
    const safe = (s: string) => s.replace(/[^\w.-]+/g, "_");
    const path = console.replace(/[^\\/]*$/, `${safe(schema)}.${safe(name)}.sql`);
    await call(commands.dbExportFile(path, text));
    bindConsole(path, id);
    await editorService().openFile(path, { focus: true });
  } catch (e) {
    notifications().notify({ level: "error", title: `Cannot get the definition of ${name}`, body: message(e) });
  }
}

/** Re-runs the statement of result tab `tabId`, replacing its rows (a plan tab explains it again). */
export async function rerunResult(tabId: number): Promise<void> {
  const tab = useDatabase.getState().results.find((r) => r.id === tabId);
  if (!tab || tab.busy) return;
  const patch = (p: Partial<ResultTab>) =>
    useDatabase.setState((s) => ({ results: s.results.map((r) => (r.id === tabId ? { ...r, ...p } : r)) }));
  patch({ busy: true });
  if (tab.plan) {
    try {
      patch({ plan: await explain(tab.sourceId, tab.outcome.statement), busy: false });
    } catch (e) {
      patch({ busy: false });
      if (!isCancelled(e)) log("error", `[${targetLabel(tab.sourceId)}] ${message(e)}`);
    }
    return;
  }
  try {
    const [outcome] = await run(tab.sourceId, [tab.outcome.statement], nextRequestId());
    patch(outcome?.result ? { outcome, busy: false } : { busy: false });
    if (outcome?.error) useDatabase.setState({ activeResult: OUTPUT_TAB });
  } catch (e) {
    patch({ busy: false });
    if (!isCancelled(e)) log("error", message(e));
  }
}

/** Statements that only read (they leave a manual transaction clean). */
const READS = /^\s*(select|show|pragma|explain|describe|desc|values|table)\b/i;

function setPending(id: string, pending: boolean) {
  useDatabase.setState((s) => {
    const pendingTx = new Set(s.pendingTx);
    if (pending) pendingTx.add(id);
    else pendingTx.delete(id);
    return { pendingTx };
  });
}

/** Commits or rolls back the open transaction of a manual-commit data source. */
export async function finishTransaction(id: string, commit: boolean): Promise<boolean> {
  try {
    await call(commands.dbFinishTransaction(id, commit));
    log("statement", commit ? "commit" : "rollback", `${promptOf(id)}>`);
    log("result", commit ? "Transaction committed" : "Transaction rolled back");
    setPending(id, false);
    return true;
  } catch (e) {
    log("error", `[${targetLabel(id)}] ${message(e)}`);
    notifications().notify({ level: "error", title: commit ? "Cannot commit" : "Cannot roll back", body: message(e) });
    return false;
  }
}

/** Leaving manual commit with changes pending (IDEA asks the same); null when cancelled. */
async function askEndTransaction(source: DataSource): Promise<boolean | null> {
  const { button } = await ask({
    title: "Switch to Auto-Commit",
    body: tx`${source.name} has uncommitted changes. Commit or roll them back before switching to auto-commit?`,
    buttons: [
      { id: "rollback", label: "Roll Back" },
      { id: "commit", label: "Commit", primary: true },
    ],
  });
  return button === "cancel" ? null : button === "commit";
}

/**
 * IDEA's Tx: Auto / Manual. Leaving manual mode with changes pending asks
 * whether to commit or roll them back.
 */
export async function setManualCommit(id: string, manual: boolean): Promise<void> {
  const st = useDatabase.getState();
  if (manual === st.manualCommit.has(id)) return;
  if (!manual && st.pendingTx.has(id)) {
    const source = sourceById(id);
    const commit = source ? await askEndTransaction(source) : false;
    if (commit === null || !(await finishTransaction(id, commit))) return;
  }
  await call(commands.dbSetManualCommit(id, manual));
  useDatabase.setState((s) => {
    const manualCommit = new Set(s.manualCommit);
    if (manual) manualCommit.add(id);
    else manualCommit.delete(id);
    return { manualCommit };
  });
  setPending(id, false);
}

export function cancelConsole(path: string) {
  const r = useDatabase.getState().running[path];
  if (r) void commands.cancelRequest(r);
}

export function closeResult(id: number) {
  useDatabase.setState((s) => {
    const results = s.results.filter((r) => r.id !== id);
    return { results, activeResult: s.activeResult === id ? (results.at(-1)?.id ?? OUTPUT_TAB) : s.activeResult };
  });
}