import Maybe from "../tsutils/Maybe";
import { getLocation } from "../language";
import { ASTNode } from "../language/ast";
import { Source } from "../language/source";
import { SourceLocation } from "../language/location";

/**
 * A GraphQLError describes an Error found during the parse, validate, or
 * execute phases of performing a GraphQL operation. In addition to a message
 * and stack trace, it also includes information about the locations in a
 * GraphQL document and/or execution result that correspond to the Error.
 */
export class GraphQLError extends Error {
    /**
     * A message describing the Error for debugging purposes.
     *
     * Enumerable, and appears in the result of JSON.stringify().
     *
     * Note: should be treated as readonly, despite invariant usage.
     */
    message: string;

    /**
     * An array of { line, column } locations within the source GraphQL document
     * which correspond to this error.
     *
     * Errors during validation often contain multiple locations, for example to
     * point out two things with the same name. Errors during execution include a
     * single location, the field which produced the error.
     *
     * Enumerable, and appears in the result of JSON.stringify().
     */
    readonly locations: ReadonlyArray<SourceLocation> | undefined;

    /**
     * An array describing the JSON-path into the execution response which
     * corresponds to this error. Only included for errors during execution.
     *
     * Enumerable, and appears in the result of JSON.stringify().
     */
    readonly path: ReadonlyArray<string | number> | undefined;

    /**
     * An array of GraphQL AST Nodes corresponding to this error.
     */
    readonly nodes: ReadonlyArray<ASTNode> | undefined;

    /**
     * The source GraphQL document corresponding to this error.
     */
    readonly source: Source | undefined;

    /**
     * An array of character offsets within the source GraphQL document
     * which correspond to this error.
     */
    readonly positions: ReadonlyArray<number> | undefined;

    /**
     * The original error thrown from a field resolver during execution.
     */
    readonly originalError: Maybe<Error>;

    /**
     * Extension fields to add to the formatted error.
     */
    readonly extensions: { [key: string]: any } | undefined;

    constructor(
        message: string,
        nodes?: ReadonlyArray<ASTNode> | ASTNode | undefined,
        source?: Maybe<Source>,
        positions?: Maybe<ReadonlyArray<number>>,
        path?: Maybe<ReadonlyArray<string | number>>,
        originalError?: Maybe<Error>,
        extensions?: Maybe<{ [key: string]: any }>
    );
}