import { FormEvent, useEffect, useState } from "react";
import { useSearchParams } from "react-router-dom";
import { Code2, Database, Play, Plug, RefreshCw, Table2, Unplug } from "lucide-react";
import { useMutation, useQuery } from "@tanstack/react-query";
import { useAccountId } from "@/lib/accountStore";
import {
  listSqlDatabases,
  listSqlTables,
  querySql,
} from "@/api/cloudProxyClient";
import type { CloudProvider } from "@/types/cloud";
import type {
  CloudResource,
  SqlCredentials,
  SqlDatabase,
  SqlEngine,
  SqlQueryResult,
  SqlTable,
} from "@/types/resource";

const SQL_SERVER_DEFAULT_QUERY = `SELECT
  DB_NAME() AS database_name,
  @@SERVERNAME AS server_name,
  @@VERSION AS version;`;
const POSTGRES_DEFAULT_QUERY = `SELECT
  current_database() AS database_name,
  current_user AS username,
  version();`;
const MYSQL_DEFAULT_QUERY = `SELECT
  DATABASE() AS database_name,
  CURRENT_USER() AS username,
  VERSION() AS version;`;

interface AzureSqlPanelProps {
  cloud: CloudProvider;
  resource?: CloudResource;
  runtimeReachable: boolean;
}

export function AzureSqlPanel({
  cloud,
  resource,
  runtimeReachable,
}: AzureSqlPanelProps) {
  const accountId = useAccountId();
  const serverId = resource?.id;
  const isAwsRds = cloud === "aws" && resource?.type === "db-instance";
  const engine: SqlEngine = isAwsRds
    ? resource?.engine === "mysql" ? "mysql" : "postgresql"
    : resource?.type === "postgres-flexible-server" ? "postgresql" : "azure-sql";
  const defaultDatabase = engine === "postgresql" ? "postgres" : engine === "mysql" ? "mysql" : "master";
  const defaultQuery =
    engine === "postgresql" ? POSTGRES_DEFAULT_QUERY : engine === "mysql" ? MYSQL_DEFAULT_QUERY : SQL_SERVER_DEFAULT_QUERY;
  const administratorLogin = metadataString(
    resource?.metadata.administratorLogin,
  );
  const [username, setUsername] = useState("");
  const [password, setPassword] = useState("");
  const [connected, setConnected] = useState(false);
  const [databases, setDatabases] = useState<SqlDatabase[]>([]);
  const [searchParams, setSearchParams] = useSearchParams();
  const selectedDatabase = searchParams.get("database") || defaultDatabase;
  const tableSchema = searchParams.get("schema");
  const tableName = searchParams.get("table");
  const [queryText, setQueryText] = useState(defaultQuery);

  const credentials: SqlCredentials = { username, password };
  const databaseExists = databases.some((database) => database.name === selectedDatabase);

  const tablesQuery = useQuery({
    queryKey: ['sql-tables', accountId, cloud, serverId, engine, selectedDatabase, username],
    queryFn: ({signal}) => listSqlTables(cloud, serverId ?? "", engine, selectedDatabase, credentials, signal),
    enabled: connected && databaseExists && runtimeReachable,
    gcTime: 0,
  });
  const tables = connected && databaseExists ? tablesQuery.data ?? [] : [];
  const selectedTable = tables.find((table) => table.schema === tableSchema && table.name === tableName);
  const previewQuery = selectedTable && tablePreviewQuery(selectedTable, engine);

  const databasesMut = useMutation({
    mutationFn: () =>
      listSqlDatabases(cloud, serverId ?? "", engine, credentials),
  });

  const queryMut = useMutation({
    mutationFn: ({ database, query }: { database: string; query: string }) =>
      querySql(cloud, serverId ?? "", engine, database, credentials, query),
  });
  const {mutate: executeQuery, reset: resetQuery} = queryMut;

  useEffect(() => {
    resetQuery();
    if (!connected || !previewQuery) {
      setQueryText(defaultQuery);
      return;
    }
    setQueryText(previewQuery);
    executeQuery({database: selectedDatabase, query: previewQuery});
  }, [connected, selectedDatabase, previewQuery, defaultQuery, executeQuery, resetQuery]);

  useEffect(() => {
    setUsername(administratorLogin);
    setPassword("");
    setConnected(false);
    setDatabases([]);
    setQueryText(defaultQuery);
  }, [administratorLogin, cloud, defaultDatabase, defaultQuery, serverId]);

  if (cloud !== "azure" && !isAwsRds) return null;

  if (!serverId) {
    return (
      <section className="sql-panel">
        <div className="empty compact">
          <h3>Select an Azure database server</h3>
          <p>Databases, tables, rows, and SQL queries load after connection.</p>
        </div>
      </section>
    );
  }

  function connect(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
    if (!isAwsRds && (!username || !password)) return;
    queryMut.reset();
    loadDatabases();
  }

  function loadDatabases() {
    databasesMut.mutate(undefined, {
      onSuccess: (items) => {
        setDatabases(items);
        setConnected(true);
        if (!searchParams.has('database')) {
          const database = items.find((item) => item.name === defaultDatabase) ?? items[0];
          if (database) selectDatabase(database);
        }
      },
    });
  }

  function disconnect() {
    setConnected(false);
    setPassword("");
    setDatabases([]);
    databasesMut.reset();
    queryMut.reset();
  }

  function selectDatabase(database: SqlDatabase) {
    setSearchParams((previous) => {
      const next = new URLSearchParams(previous);
      next.set('database', database.name);
      next.delete('schema');
      next.delete('table');
      return next;
    });
  }

  function previewTable(table: SqlTable) {
    if (table.schema === tableSchema && table.name === tableName) {
      const query = tablePreviewQuery(table, engine);
      setQueryText(query);
      queryMut.mutate({database: selectedDatabase, query});
      return;
    }
    setSearchParams((previous) => {
      const next = new URLSearchParams(previous);
      next.set('database', selectedDatabase);
      next.set('schema', table.schema);
      next.set('table', table.name);
      return next;
    });
  }

  function runQuery() {
    if (!queryText.trim()) return;
    queryMut.mutate({ database: selectedDatabase, query: queryText });
  }

  const connectionError =
    databasesMut.error instanceof Error ? databasesMut.error.message : null;

  return (
    <section className="sql-panel">
      <form className="sql-connection-bar" onSubmit={connect}>
        <div className="sql-connection-title">
          <Plug size={16} />
          <span>
            <small>{isAwsRds ? "RDS DATA API" : engine === "postgresql" ? "POSTGRESQL DATA PLANE" : "SQL DATA PLANE"}</small>
            <strong>{resource.name}</strong>
            <em>{isAwsRds ? `${resource.engine} · ${resource.status ?? "unknown"}` : metadataString(resource.metadata.fullyQualifiedDomainName)}</em>
          </span>
        </div>
        {!isAwsRds && <label>
          <span>Username</span>
          <input
            className="input"
            value={username}
            onChange={(event) => setUsername(event.target.value)}
            disabled={connected || !runtimeReachable}
            autoComplete="username"
          />
        </label>}
        {!isAwsRds && <label>
          <span>Password</span>
          <input
            className="input"
            type="password"
            value={password}
            onChange={(event) => setPassword(event.target.value)}
            disabled={connected || !runtimeReachable}
            autoComplete="current-password"
          />
        </label>}
        {connected ? (
          <button className="button" type="button" onClick={disconnect}>
            <Unplug size={14} />
            Disconnect
          </button>
        ) : (
          <button
            className="button primary"
            type="submit"
            disabled={
              !runtimeReachable ||
              databasesMut.isPending ||
              (!isAwsRds && (!username || !password))
            }
          >
            <Plug size={14} />
            {databasesMut.isPending ? "Connecting" : "Connect"}
          </button>
        )}
        <small className="sql-credential-note">
          {isAwsRds
            ? "Queries use TheCloud's local RDS Data API credentials. Database passwords are not sent by the console."
            : "Credentials remain in this page only and are sent to the local API per request."}
        </small>
        {connectionError && <div className="form-error">{connectionError}</div>}
      </form>

      {!connected ? (
        <div className="empty compact sql-connect-empty">
          <h3>Connect to browse SQL data</h3>
          <p>{isAwsRds ? "Connect through TheCloud's local RDS Data API to browse databases and run SQL." : "Use the administrator login configured for this local engine."}</p>
        </div>
      ) : (
        <div className="sql-explorer">
          <div className="sql-column">
            <SqlPanelHeader
              icon={Database}
              eyebrow="Databases"
              title={resource.name}
              detail={`${databases.length} databases`}
              action={
                <button
                  className="icon-btn"
                  type="button"
                  title="Refresh databases"
                  disabled={databasesMut.isPending}
                  onClick={loadDatabases}
                >
                  <RefreshCw size={13} />
                </button>
              }
            />
            <div className="sql-list">
              {databases.length === 0 && <div className="muted padded">No databases</div>}
              {databases.length > 0 && !databaseExists && <div className="form-error">Database not found: {selectedDatabase}</div>}
              {databases.map((database) => (
                <button
                  key={database.name}
                  className={`sql-list-row ${selectedDatabase === database.name ? "selected" : ""}`}
                  type="button"
                  onClick={() => selectDatabase(database)}
                >
                  <span>
                    <strong>{database.name}</strong>
                    <small>{database.state}</small>
                  </span>
                  {database.isSystem && <em>System</em>}
                </button>
              ))}
            </div>
          </div>

          <div className="sql-column">
            <SqlPanelHeader
              icon={Table2}
              eyebrow="Tables and views"
              title={selectedDatabase}
              detail={`${tables.length} objects`}
              action={
                <button
                  className="icon-btn"
                  type="button"
                  title="Refresh tables"
                  disabled={!databaseExists || tablesQuery.isFetching}
                  onClick={() => void tablesQuery.refetch()}
                >
                  <RefreshCw size={13} />
                </button>
              }
            />
            {tablesQuery.error instanceof Error && (
              <div className="form-error">{tablesQuery.error.message}</div>
            )}
            <div className="sql-list">
              {tablesQuery.isLoading && <div className="muted padded">Loading objects</div>}
              {databaseExists && tablesQuery.isSuccess && tables.length === 0 && (
                <div className="muted padded">No user tables or views</div>
              )}
              {databaseExists && tablesQuery.isSuccess && tableName && !selectedTable && <div className="form-error">Table not found: {tableSchema}.{tableName}</div>}
              {tables.map((table) => (
                <button
                  key={`${table.schema}.${table.name}`}
                  className={`sql-list-row ${selectedTable?.schema === table.schema && selectedTable.name === table.name ? "selected" : ""}`}
                  type="button"
                  onClick={() => previewTable(table)}
                >
                  <span>
                    <strong>{table.schema}.{table.name}</strong>
                    <small>{table.type}</small>
                  </span>
                  <em>{table.rowCount === null ? "—" : `${table.rowCount} rows`}</em>
                </button>
              ))}
            </div>
          </div>

          <div className="sql-column sql-workspace">
            <SqlPanelHeader
              icon={Code2}
              eyebrow="Query editor"
              title={selectedDatabase}
              detail={engine === "postgresql"
                ? "PostgreSQL SQL against selected database"
                : engine === "mysql"
                ? "MySQL SQL against selected database"
                : "T-SQL against selected database"}
            />
            <div className="sql-query-editor">
              <textarea
                className="textarea code-textarea small"
                value={queryText}
                onChange={(event) => setQueryText(event.target.value)}
                spellCheck={false}
              />
              <button
                className="button primary"
                type="button"
                disabled={!databaseExists || queryMut.isPending || !queryText.trim()}
                onClick={runQuery}
              >
                <Play size={14} />
                {queryMut.isPending ? "Running" : "Run query"}
              </button>
            </div>
            {queryMut.error instanceof Error && (
              <div className="form-error">{queryMut.error.message}</div>
            )}
            <SqlQueryResults result={queryMut.data} />
          </div>
        </div>
      )}
    </section>
  );
}

function SqlQueryResults({ result }: { result?: SqlQueryResult }) {
  if (!result) {
    return (
      <div className="empty compact sql-results-empty">
        <h3>No query results</h3>
        <p>Select a table for a 100-row preview or run SQL.</p>
      </div>
    );
  }

  const affected = result.rowsAffected.reduce((total, count) => total + count, 0);

  return (
    <div className="sql-results">
      <div className="sql-results-summary">
        <span>{result.resultSets.length} result sets</span>
        <span>{affected} rows affected</span>
        <span>{result.durationMs} ms</span>
      </div>
      {result.resultSets.length === 0 && (
        <div className="muted padded">Command completed without a result set.</div>
      )}
      {result.resultSets.map((resultSet, resultSetIndex) => (
        <div className="sql-result-set" key={resultSetIndex}>
          <div className="sql-result-set-label">
            Result {resultSetIndex + 1} · {resultSet.rows.length} rows
            {resultSet.truncated && " · first 500 shown"}
          </div>
          <div className="sql-result-table-wrap">
            <table className="table sql-result-table">
              <thead>
                <tr>
                  {resultSet.columns.map((column) => (
                    <th key={column.name} title={column.type}>
                      {column.name}
                      <small>{column.type}</small>
                    </th>
                  ))}
                </tr>
              </thead>
              <tbody>
                {resultSet.rows.map((row, rowIndex) => (
                  <tr key={rowIndex}>
                    {resultSet.columns.map((column) => {
                      const value = formatSqlValue(row[column.name]);
                      return (
                        <td key={column.name} title={value}>
                          {value}
                        </td>
                      );
                    })}
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        </div>
      ))}
    </div>
  );
}

function SqlPanelHeader({
  icon: Icon,
  eyebrow,
  title,
  detail,
  action,
}: {
  icon: typeof Database;
  eyebrow: string;
  title: string;
  detail: string;
  action?: React.ReactNode;
}) {
  return (
    <div className="sql-panel-header">
      <Icon size={15} />
      <span>
        <small>{eyebrow}</small>
        <strong>{title}</strong>
        <em>{detail}</em>
      </span>
      {action}
    </div>
  );
}

function metadataString(value: unknown): string {
  return typeof value === "string" ? value : "";
}

function tablePreviewQuery(table: SqlTable, engine: SqlEngine): string {
  const tableName = `${quoteIdentifier(table.schema, engine)}.${quoteIdentifier(table.name, engine)}`;
  return engine === 'postgresql'
    ? `SELECT * FROM ${tableName} LIMIT 100;`
    : engine === 'mysql'
    ? `SELECT * FROM ${tableName} LIMIT 100;`
    : `SELECT TOP (100) * FROM ${tableName};`;
}

function quoteIdentifier(value: string, engine: SqlEngine): string {
  return engine === "mysql"
    ? `\`${value.replace(/`/g, "``")}\``
    : engine === "postgresql"
    ? `"${value.replace(/"/g, '""')}"`
    : `[${value.replace(/]/g, "]]")}]`;
}

function formatSqlValue(value: unknown): string {
  if (value === null || value === undefined) return "NULL";
  if (typeof value === "object") return JSON.stringify(value);
  return String(value);
}