import type { SQLDialect } from "@codemirror/lang-sql";

export type CodeMirrorSqlDialectName = "mysql" | "postgres" | "sqlserver";

type CodeMirrorSqlLanguageModule = Pick<typeof import("@codemirror/lang-sql"), "MSSQL" | "MySQL" | "PostgreSQL" | "SQLDialect">;

const DBX_COMMON_SQL_KEYWORDS = [
  "PIVOT",
  "UNPIVOT",
  "EXCLUDE",
  "REPLACE",
  "QUALIFY",
  "ASOF",
  "POSITIONAL",
  "ANTI",
  "SEMI",
  "SAMPLE",
  "TABLESAMPLE",
  "STRUCT",
  "MAP",
  "LIST",
  "ARRAY",
  "LAMBDA",
  "UNNEST",
  "LATERAL",
  "FILTER",
  "RECURSIVE",
  "SUMMARIZE",
  "PRAGMA",
  "READ_CSV",
  "READ_PARQUET",
  "READ_JSON",
  "DESCRIBE",
  "SHOW",
  "COPY",
  "EXPORT",
  "IMPORT",
].join(" ");

const POSTGRES_PLPGSQL_KEYWORDS = "PERFORM";
const POSTGRES_PLPGSQL_TYPES = "RECORD JSON JSONB";
const POSTGRES_PLPGSQL_BUILTIN = "SQLERRM TG_NAME TG_WHEN TG_LEVEL TG_OP TG_RELID TG_RELNAME TG_TABLE_NAME TG_TABLE_SCHEMA TG_NARGS TG_ARGV";

// SQL Server table-valued parameters require READONLY in procedure/function declarations.
const SQLSERVER_KEYWORDS = "readonly";

export function createDbxCodeMirrorSqlDialect(langSql: CodeMirrorSqlLanguageModule, dialectName: CodeMirrorSqlDialectName = "mysql"): SQLDialect {
  const baseDialect = dialectName === "postgres" ? langSql.PostgreSQL : dialectName === "sqlserver" ? langSql.MSSQL : langSql.MySQL;
  const isPostgres = dialectName === "postgres";
  const isSqlServer = dialectName === "sqlserver";

  return langSql.SQLDialect.define({
    ...baseDialect.spec,
    keywords: [baseDialect.spec.keywords || "", DBX_COMMON_SQL_KEYWORDS, isPostgres ? POSTGRES_PLPGSQL_KEYWORDS : "", isSqlServer ? SQLSERVER_KEYWORDS : ""].filter(Boolean).join(" "),
    types: [baseDialect.spec.types || "", isPostgres ? POSTGRES_PLPGSQL_TYPES : ""].filter(Boolean).join(" ") || undefined,
    builtin: [baseDialect.spec.builtin || "", isPostgres ? POSTGRES_PLPGSQL_BUILTIN : ""].filter(Boolean).join(" ") || undefined,
    doubleDollarQuotedStrings: false,
  });
}