#include <destrum/Input/InputManager.h>
#include <algorithm>
#include <cmath>

static float NormalizeAxis(Sint16 v, int deadzone) {
    // Deadzone in raw units. Return [-1..1]
    const int iv = (int)v;

    if (std::abs(iv) <= deadzone) return 0.0f;

    // Normalize to [-1..1] while preserving sign.
    // SDL axis range is roughly [-32768..32767]
    const float denom = (iv < 0) ? 32768.0f : 32767.0f;
    float f = (float)iv / denom;

    // Optional: re-scale so that value starts at 0 outside deadzone
    // (nice for sticks; comment out if you prefer raw normalize)
    const float dz = (float)deadzone / 32767.0f;
    const float sign = (f < 0.0f) ? -1.0f : 1.0f;
    const float af = std::abs(f);
    const float scaled = (af - dz) / (1.0f - dz);
    return sign * std::clamp(scaled, 0.0f, 1.0f);
}

void InputManager::Init() {
    // Make sure gamecontroller subsystem is active (safe even if already)
    SDL_InitSubSystem(SDL_INIT_GAMECONTROLLER);

    // Open any controllers already connected
    const int num = SDL_NumJoysticks();
    for (int i = 0; i < num; ++i) {
        if (SDL_IsGameController(i)) {
            AddController(i);
        }
    }
}

void InputManager::BeginFrame() {
    m_keysPressed.clear();
    m_keysReleased.clear();
    m_mousePressed.clear();
    m_mouseReleased.clear();

    m_wheelX = 0;
    m_wheelY = 0;

    m_textInput.clear();

    // Relative mouse accumulators are filled during SDL event processing
    // and consumed by game code each frame. Reset them here (before events
    // are processed) so this frame accumulates fresh deltas.
    m_mouseRelDX = 0;
    m_mouseRelDY = 0;

    // Clear controller "edge" sets + snapshot axes
    for (auto& [id, pad]: m_pads) {
        pad.buttonsPressed.clear();
        pad.buttonsReleased.clear();
        pad.prevAxes = pad.axes;
    }
}

void InputManager::SetMouseCaptured(bool captured) {
    if (captured == m_MouseCaptured) return;
    m_MouseCaptured = captured;
    SDL_SetRelativeMouseMode(captured ? SDL_TRUE : SDL_FALSE);
}

void InputManager::AddController(int deviceIndex) {
    if (!SDL_IsGameController(deviceIndex)) return;

    SDL_GameController* gc = SDL_GameControllerOpen(deviceIndex);
    if (!gc) return;

    SDL_Joystick* joy = SDL_GameControllerGetJoystick(gc);
    SDL_JoystickID instanceId = SDL_JoystickInstanceID(joy);

    PadState ps;
    ps.controller = gc;
    ps.instanceId = instanceId;
    ps.axes.fill(0);
    ps.prevAxes.fill(0);

    m_pads[instanceId] = ps;

    // Track order (padIndex mapping)
    m_padOrder.push_back(instanceId);
}

void InputManager::RemoveController(SDL_JoystickID instanceId) {
    auto it = m_pads.find(instanceId);
    if (it != m_pads.end()) {
        if (it->second.controller) {
            SDL_GameControllerClose(it->second.controller);
        }
        m_pads.erase(it);
    }

    // Remove from order list
    m_padOrder.erase(
        std::remove(m_padOrder.begin(), m_padOrder.end(), instanceId),
        m_padOrder.end()
    );
}

bool InputManager::ProcessEvent(const SDL_Event& e) {
    switch (e.type) {
        case SDL_QUIT: {
            return true;
        }
        case SDL_KEYDOWN: {
            if (e.key.repeat) break;
            SDL_Scancode sc = e.key.keysym.scancode;
            m_keysDown.insert(sc);
            m_keysPressed.insert(sc);
        }
        break;

        case SDL_KEYUP: {
            SDL_Scancode sc = e.key.keysym.scancode;
            m_keysDown.erase(sc);
            m_keysReleased.insert(sc);
        }
        break;

        case SDL_MOUSEBUTTONDOWN: {
            Uint8 b = e.button.button;
            m_mouseDown.insert(b);
            m_mousePressed.insert(b);
        }
        break;

        case SDL_MOUSEBUTTONUP: {
            Uint8 b = e.button.button;
            m_mouseDown.erase(b);
            m_mouseReleased.insert(b);
        }
        break;

        case SDL_MOUSEMOTION: {
            m_mouseX = e.motion.x;
            m_mouseY = e.motion.y;
            m_mouseRelDX += e.motion.xrel;
            m_mouseRelDY += e.motion.yrel;
        }
        break;

        case SDL_MOUSEWHEEL: {
            m_wheelX += e.wheel.x;
            m_wheelY += e.wheel.y;
        }
        break;

        case SDL_TEXTINPUT: {
            m_textInput += e.text.text;
        }
        break;

        // ---- Controller hotplug ----
        case SDL_CONTROLLERDEVICEADDED: {
            // e.cdevice.which is the device index here
            AddController(e.cdevice.which);
        }
        break;

        case SDL_CONTROLLERDEVICEREMOVED: {
            // e.cdevice.which is instanceId here
            RemoveController((SDL_JoystickID)e.cdevice.which);
        }
        break;

        // ---- Controller buttons ----
        case SDL_CONTROLLERBUTTONDOWN: {
            SDL_JoystickID id = (SDL_JoystickID)e.cbutton.which;
            auto it = m_pads.find(id);
            if (it == m_pads.end()) break;

            uint8_t btn = (uint8_t)e.cbutton.button;
            it->second.buttonsDown.insert(btn);
            it->second.buttonsPressed.insert(btn);
        }
        break;

        case SDL_CONTROLLERBUTTONUP: {
            SDL_JoystickID id = (SDL_JoystickID)e.cbutton.which;
            auto it = m_pads.find(id);
            if (it == m_pads.end()) break;

            uint8_t btn = (uint8_t)e.cbutton.button;
            it->second.buttonsDown.erase(btn);
            it->second.buttonsReleased.insert(btn);
        }
        break;

        // ---- Controller axes ----
        case SDL_CONTROLLERAXISMOTION: {
            SDL_JoystickID id = (SDL_JoystickID)e.caxis.which;
            auto it = m_pads.find(id);
            if (it == m_pads.end()) break;

            const int axis = (int)e.caxis.axis;
            if (axis >= 0 && axis < SDL_CONTROLLER_AXIS_MAX) {
                it->second.axes[(size_t)axis] = e.caxis.value;
            }
        }
        break;

        default: break;
    }
    return false;
}

bool InputManager::IsKeyDown(SDL_Scancode sc) const { return m_keysDown.count(sc) != 0; }
bool InputManager::WasKeyPressed(SDL_Scancode sc) const { return m_keysPressed.count(sc) != 0; }
bool InputManager::WasKeyReleased(SDL_Scancode sc) const { return m_keysReleased.count(sc) != 0; }

bool InputManager::IsMouseDown(Uint8 button) const { return m_mouseDown.count(button) != 0; }
bool InputManager::WasMousePressed(Uint8 button) const { return m_mousePressed.count(button) != 0; }
bool InputManager::WasMouseReleased(Uint8 button) const { return m_mouseReleased.count(button) != 0; }

void InputManager::StartTextInput() {
    if (!m_textInputActive) {
        SDL_StartTextInput();
        m_textInputActive = true;
    }
}

void InputManager::StopTextInput() {
    if (m_textInputActive) {
        SDL_StopTextInput();
        m_textInputActive = false;
    }
}

// ---- Controller direct queries ----
SDL_JoystickID InputManager::GetPadInstanceId(uint8_t padIndex) const {
    if (padIndex >= m_padOrder.size()) return -1;
    return m_padOrder[padIndex];
}

bool InputManager::IsPadButtonDown(SDL_JoystickID id, SDL_GameControllerButton btn) const {
    auto it = m_pads.find(id);
    if (it == m_pads.end()) return false;
    return it->second.buttonsDown.count((uint8_t)btn) != 0;
}

bool InputManager::WasPadButtonPressed(SDL_JoystickID id, SDL_GameControllerButton btn) const {
    auto it = m_pads.find(id);
    if (it == m_pads.end()) return false;
    return it->second.buttonsPressed.count((uint8_t)btn) != 0;
}

bool InputManager::WasPadButtonReleased(SDL_JoystickID id, SDL_GameControllerButton btn) const {
    auto it = m_pads.find(id);
    if (it == m_pads.end()) return false;
    return it->second.buttonsReleased.count((uint8_t)btn) != 0;
}

float InputManager::GetPadAxis(SDL_JoystickID id, SDL_GameControllerAxis axis) const {
    auto it = m_pads.find(id);
    if (it == m_pads.end()) return 0.0f;
    const int a = (int)axis;
    if (a < 0 || a >= SDL_CONTROLLER_AXIS_MAX) return 0.0f;
    return NormalizeAxis(it->second.axes[(size_t)a], m_axisDeadzone);
}

// ---- Binding helpers ----
InputManager::Binding InputManager::PadButton(uint8_t padIndex, SDL_GameControllerButton btn) {
    Binding b;
    b.device = Device::GamepadButton;
    b.code = ((int)padIndex << 8) | ((int)btn & 0xFF);
    return b;
}

InputManager::Binding InputManager::PadAxis(uint8_t padIndex, SDL_GameControllerAxis axis, int sign, float threshold) {
    Binding b;
    b.device = Device::GamepadAxis;
    b.code = ((int)padIndex << 8) | ((int)axis & 0xFF);
    b.sign = (sign < 0) ? -1 : +1;
    b.threshold = threshold;
    return b;
}

// ---- Action mapping ----
void InputManager::BindAction(const std::string& action, const Binding& binding) {
    m_bindings[action].push_back(binding);
}

bool InputManager::QueryBinding(const Binding& b, ButtonState state) const {
    switch (b.device) {
        case Device::Keyboard: {
            auto sc = static_cast<SDL_Scancode>(b.code);
            if (state == ButtonState::Down) return IsKeyDown(sc);
            if (state == ButtonState::Pressed) return WasKeyPressed(sc);
            if (state == ButtonState::Released) return WasKeyReleased(sc);
        }
        break;

        case Device::MouseButton: {
            auto mb = static_cast<Uint8>(b.code);
            if (state == ButtonState::Down) return IsMouseDown(mb);
            if (state == ButtonState::Pressed) return WasMousePressed(mb);
            if (state == ButtonState::Released) return WasMouseReleased(mb);
        }
        break;

        case Device::MouseWheel: {
            const int c = b.code;
            if (state != ButtonState::Pressed) return false;
            if (c == 1) return m_wheelY > 0;
            if (c == -1) return m_wheelY < 0;
            if (c == 2) return m_wheelX > 0;
            if (c == -2) return m_wheelX < 0;
        }
        break;

        case Device::GamepadButton: {
            const uint8_t padIndex = GetPadIndexFromCode(b.code);
            const uint8_t btn = GetLow8FromCode(b.code);

            const SDL_JoystickID id = GetPadInstanceId(padIndex);
            if (id < 0) return false;

            if (state == ButtonState::Down) return IsPadButtonDown(id, (SDL_GameControllerButton)btn);
            if (state == ButtonState::Pressed) return WasPadButtonPressed(id, (SDL_GameControllerButton)btn);
            if (state == ButtonState::Released) return WasPadButtonReleased(id, (SDL_GameControllerButton)btn);
        }
        break;

        case Device::GamepadAxis: {
            // Axis bindings are treated as "digital" by thresholding
            const uint8_t padIndex = GetPadIndexFromCode(b.code);
            const uint8_t axis = GetLow8FromCode(b.code);

            const SDL_JoystickID id = GetPadInstanceId(padIndex);
            if (id < 0) return false;

            auto it = m_pads.find(id);
            if (it == m_pads.end()) return false;

            if (axis >= SDL_CONTROLLER_AXIS_MAX) return false;

            const float cur = NormalizeAxis(it->second.axes[axis], m_axisDeadzone) * (float)b.sign;
            const float prev = NormalizeAxis(it->second.prevAxes[axis], m_axisDeadzone) * (float)b.sign;

            const bool curOn = cur >= b.threshold;
            const bool prevOn = prev >= b.threshold;

            if (state == ButtonState::Down) return curOn;
            if (state == ButtonState::Pressed) return (curOn && !prevOn);
            if (state == ButtonState::Released) return (!curOn && prevOn);
        }
        break;
    }
    return false;
}

bool InputManager::GetAction(const std::string& action, ButtonState state) const {
    auto it = m_bindings.find(action);
    if (it == m_bindings.end()) return false;

    for (const auto& b: it->second) {
        if (QueryBinding(b, state)) return true;
    }
    return false;
}