// SPDX-License-Identifier: LGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

export module Crafter.DB:Error;
import std;

export namespace Crafter::DB {
    // Root of every exception the library throws. Catch this to handle
    // "the table is unusable" uniformly; catch the subclasses to react.
    class Error : public std::runtime_error {
    public:
        using std::runtime_error::runtime_error;
    };

    // A system call failed. `code` carries errno, `path` the file involved.
    class IOError : public Error {
    public:
        IOError(std::string_view what, std::error_code code, std::filesystem::path path)
            : Error(std::format("{}: {} ({})", path.string(), what, code.message())), code(code), path(std::move(path)) {}

        std::error_code code;
        std::filesystem::path path;
    };

    // The file is not a Crafter.DB table or its header/commit records fail
    // validation (bad magic, both commit CRCs wrong, extents outside the file).
    class CorruptError : public Error {
    public:
        using Error::Error;
    };

    // The compiled struct and the file disagree: same version but a different
    // fingerprint (struct changed without bumping `version`), a file newer
    // than the code, or no `Previous` chain reaching the file's version.
    class SchemaError : public Error {
    public:
        using Error::Error;
    };

    // A migration is needed but cannot run: the table was opened read-only or
    // with `migrate = false`.
    class MigrationError : public Error {
    public:
        using Error::Error;
    };

    // Another process (or another Table object in this process) holds the
    // file lock in a conflicting mode.
    class LockedError : public Error {
    public:
        using Error::Error;
    };

    // A write would break the order of the `orderedBy` column.
    class OrderError : public Error {
    public:
        using Error::Error;
    };

    // A write was attempted on a table opened with `readOnly = true`.
    class ReadOnlyError : public Error {
    public:
        using Error::Error;
    };
}