#pragma once

#include <memory>
#include <stdexcept>
#include <string>
#include <vector>

#include "core/image.hpp"
#include "core/params.hpp"
#include "core/rng.hpp"

namespace effector {

class EffectError : public std::runtime_error {
public:
    using std::runtime_error::runtime_error;
};

// Base class for every effect. Canvas size and the random source are common to
// all of them; params() covers only the effect-specific knobs.
class Effect {
public:
    virtual ~Effect() = default;

    virtual std::string name() const = 0;
    virtual std::string title() const = 0;
    virtual std::string description() const = 0;
    virtual const std::vector<ParamSpec>& params() const = 0;

    // Whether the effect builds its image out of the loaded source images.
    // Effects that only transform what they are handed (blur) say no, and a
    // chain that starts with one of them needs no sources at all.
    virtual bool needsSources() const { return true; }

    virtual Image render(const std::vector<Image>& sources, int width, int height, Rng& rng,
                         const ParamValues& values) const = 0;

    ParamValues defaults() const;
};

using EffectPtr = std::shared_ptr<const Effect>;

}  // namespace effector