#include "serif/solver/linear/linear.hpp"

#include <algorithm>
#include <cmath>
#include <stdexcept>
#include "serif/utils/error/errors.hpp"

namespace serif::solver::linear {
    void Control::validate() const {
        utils::errors::serif_ensure<utils::errors::SERiFErrorCode::SOLVER_ERROR, std::invalid_argument>(
            std::isfinite(relative_tolerance) && relative_tolerance >= 0.0 &&
            std::isfinite(absolute_tolerance) && absolute_tolerance >= 0.0 && maximum_iterations > 0,
            "A linear solve needs finite nonnegative tolerances and a positive iteration budget; received {}, {}, and {}.",
            relative_tolerance, absolute_tolerance, maximum_iterations);
    }

    double Control::convergence_threshold(double right_hand_side_norm) const {
        validate();
        const double relative_threshold = relative_tolerance * right_hand_side_norm;
        utils::errors::serif_ensure<utils::errors::SERiFErrorCode::SOLVER_ERROR, std::invalid_argument>(
            std::isfinite(right_hand_side_norm) && right_hand_side_norm >= 0.0 && std::isfinite(relative_threshold),
            "A linear convergence threshold needs a finite nonnegative right-hand-side norm and finite product with the relative tolerance; received {}.",
            right_hand_side_norm);
        return std::max(absolute_tolerance, relative_threshold);
    }

    void FGMRES::validate() const {
        utils::errors::serif_ensure<utils::errors::SERiFErrorCode::SOLVER_ERROR, std::invalid_argument>(
            restart_length > 0 && print_level >= -1 && print_level <= 3,
            "FGMRES needs a positive restart length and print level between -1 and 3; received {} and {}.", restart_length, print_level);
    }
}