#pragma once

#include <cstdint>
#include <memory>
#include <string>
#include <string_view>
#include <vector>

class AppSystem;

struct InputState {
    bool up     = false;
    bool left   = false;
    bool right  = false;
    bool down   = false;
    bool a      = false;
    bool b      = false;
    bool select = false;
    bool start  = false;
};

class IFramebuffer {
public:
    virtual ~IFramebuffer()                       = default;
    virtual void drawPixel(int x, int y, bool on) = 0; // on=true => black
    virtual void clear(bool on)                   = 0; // fill full screen to on/off
    virtual int  width() const                    = 0;
    virtual int  height() const                   = 0;
};

class IInput {
public:
    virtual ~IInput()              = default;
    virtual InputState readState() = 0;
};

class IClock {
public:
    virtual ~IClock()                      = default;
    virtual uint32_t millis()              = 0;
    virtual void     sleep_ms(uint32_t ms) = 0;
};

struct AppContext {
    AppContext() = delete;
    AppContext(IFramebuffer& fb, IInput& in, IClock& clk) : framebuffer(fb), input(in), clock(clk) {}

    IFramebuffer& framebuffer;
    IInput&       input;
    IClock&       clock;
    AppSystem*    system = nullptr;

    void requestAppSwitchByIndex(std::size_t index) {
        pendingAppIndex = index;
        pendingAppName.clear();
        pendingSwitchByName = false;
        pendingSwitch       = true;
    }

    void requestAppSwitchByName(std::string_view name) {
        pendingAppName.assign(name.begin(), name.end());
        pendingSwitchByName = true;
        pendingSwitch       = true;
    }

    bool hasPendingAppSwitch() const { return pendingSwitch; }

private:
    friend class AppSystem;
    bool        pendingSwitch       = false;
    bool        pendingSwitchByName = false;
    std::size_t pendingAppIndex     = 0;
    std::string pendingAppName;
};

struct AppSleepPlan {
    uint32_t slow_ms   = 0; // long sleep allowing battery/UI periodic refresh
    uint32_t normal_ms = 0; // short sleep for responsiveness on input wake
};

class IApp {
public:
    virtual ~IApp() = default;
    virtual void         onStart() {}
    virtual void         onStop() {}
    virtual void         step() = 0;
    virtual AppSleepPlan sleepPlan(uint32_t now) const { return {}; }
};

class IAppFactory {
public:
    virtual ~IAppFactory()                                    = default;
    virtual const char*           name() const                = 0;
    virtual std::unique_ptr<IApp> create(AppContext& context) = 0;
};