#pragma once

#include "fgc/ICameraSource.h"
#include "fgc/Logger.h"

#include <algorithm>
#include <chrono>
#include <map>
#include <string>
#include <thread>

namespace fgc {

// Synthetic camera for development without hardware. On trigger() it generates
// a small RGB gradient frame (varying with time so successive captures differ)
// and delivers it to the frame callback. setProfile() only records the profile
// name - there is no sensor to configure - which is enough to exercise profile
// switching end to end with --mock-camera.
class MockCameraSource : public ICameraSource {
public:
    explicit MockCameraSource(int count = 1, uint32_t width = 640, uint32_t height = 480)
        : count_(count), width_(width), height_(height) {}

    void open() override { LOG_INFO << "[mock] camera opened (" << count_ << ")"; }
    void close() override {}
    void start() override { started_ = true; LOG_INFO << "[mock] camera acquisition started"; }
    void stop() override { started_ = false; }

    bool trigger() override {
        if (!callback_) return false;
        LOG_TRACE_CAT(LogCat::Camera) << "TX trigger cam0 (mock)";
        Frame f = synth();
        LOG_TRACE_CAT(LogCat::Camera)
            << "RX frame cam0 " << width_ << 'x' << height_ << ' ' << f.data.size() << "B (mock)";
        ++frames_;
        callback_(f);
        return true;
    }

    void setFrameCallback(FrameCallback cb) override { callback_ = std::move(cb); }

    // No auto-exposure to wait for: settled as soon as the gimbal is at rest, so
    // --mock-camera runs exercise the automatic settle wait.
    ExposureState exposureState() override { return ExposureState::Settled; }
    int  cameraCount() const override { return count_; }

    bool setProfile(int camera_index, const CameraProfile& profile) override {
        profile_ = profile.name;
        LOG_INFO << "[mock] camera " << camera_index << " profile -> " << profile_;
        return true;
    }

    // `test camera`. The mock behaves like the real one: minimum exposure and gain
    // drive it to black, maximum gain brightens it, so the self-test passes against
    // it - and a fault can be switched on to prove the test fails when it should.
    enum class Fault { None, NoFrames, IgnoresSettings };
    void setFault(Fault f) { fault_ = f; }

    bool grabFrame(int camera_index, Frame& out, int timeout_ms) override {
        if (!started_ || camera_index < 0 || camera_index >= count_) return false;
        if (fault_ == Fault::NoFrames) {
            std::this_thread::sleep_for(std::chrono::milliseconds(std::min(timeout_ms, 20)));
            return false;
        }
        out        = synth();
        out.cam_id = camera_index;
        ++frames_;
        return true;
    }
    bool setFeature(int camera_index, const std::string& name, const std::string& value) override {
        if (camera_index < 0 || camera_index >= count_) return false;
        features_[name] = value;
        return true;
    }
    bool featureRange(int camera_index, const std::string& name, double& min,
                      double& max) override {
        if (camera_index < 0 || camera_index >= count_) return false;
        if (name == "ExposureTime") { min = 66.357; max = 9999971.0; return true; }
        if (name == "Gain")         { min = 0.0;    max = 48.0;      return true; }
        if (name == "BlackLevel")   { min = 0.0;    max = 4095.0;    return true; }
        return false;
    }
    bool restoreProfile(int camera_index) override {
        if (camera_index < 0 || camera_index >= count_) return false;
        features_.clear();
        return true;
    }
    bool resetCamera(int camera_index) override {
        if (camera_index < 0 || camera_index >= count_) return false;
        LOG_INFO << "[mock] camera " << camera_index << " reset";
        features_.clear();
        fault_ = Fault::None;   // a reset is what clears a stuck camera
        return true;
    }

    // Synthetic device info so the expanded camera view renders (and is testable)
    // without hardware. Non-hardware fields (temperature, exposure...) stay at 0.
    std::vector<CameraDeviceInfo> deviceInfo() override {
        std::vector<CameraDeviceInfo> out;
        for (int i = 0; i < count_; ++i) {
            CameraDeviceInfo d;
            d.id               = "MOCK" + std::to_string(i);
            d.model            = "MockCamera";
            d.serial           = "SIM-0000";
            d.streaming        = started_;
            d.width            = width_;
            d.height           = height_;
            d.payload_bytes    = static_cast<long long>(width_) * height_ * 3;
            d.actual_fps       = 1.0;
            d.frames_delivered = (i == 0) ? frames_ : 0;  // only cam0 produces frames
            out.push_back(std::move(d));
        }
        return out;
    }

private:
    // A mid-grey gradient frame. The pattern varies with time so successive
    // captures differ.
    Frame synth() const {
        Frame f;
        f.width    = width_;
        f.height   = height_;
        f.channels = 3;
        f.cam_id   = 0;
        f.timestamp_ms = std::chrono::duration_cast<std::chrono::milliseconds>(
                             std::chrono::system_clock::now().time_since_epoch())
                             .count();
        f.data.resize(static_cast<size_t>(width_) * height_ * 3);

        // The scene's mid grey, unless the self-test has forced an extreme.
        double level = 110.0;
        auto num = [&](const char* k, double dflt) {
            auto it = features_.find(k);
            return it == features_.end() ? dflt : std::stod(it->second);
        };
        if (fault_ != Fault::IgnoresSettings && features_.count("ExposureTime")) {
            if (num("ExposureTime", 1e9) < 100.0 && num("Gain", 99.0) <= 0.0)
                level = -100.0;                          // minimum exposure and gain: black
            else if (num("Gain", 0.0) >= 48.0)
                level = 180.0;                           // maximum gain: visibly brighter
        }

        const uint8_t phase = static_cast<uint8_t>(f.timestamp_ms);
        for (uint32_t y = 0; y < height_; ++y) {
            for (uint32_t x = 0; x < width_; ++x) {
                size_t i = (static_cast<size_t>(y) * width_ + x) * 3;
                // Zero-mean texture around `level`. The cast matters:
                // (x+y+phase)%3 is unsigned, so subtracting 1 from the zero case
                // would wrap to UINT_MAX and clip a third of the frame to white.
                const double tex = 20.0 * (static_cast<int>((x + y + phase) % 3) - 1);
                auto clamp8 = [](double v) {
                    return static_cast<uint8_t>(v < 0 ? 0 : (v > 255 ? 255 : v));
                };
                f.data[i + 0] = clamp8(level + tex);
                f.data[i + 1] = clamp8(level + tex * 0.8);
                f.data[i + 2] = clamp8(level + tex * 0.6);
            }
        }
        return f;
    }

    int           count_;
    uint32_t      width_;
    uint32_t      height_;
    bool          started_ = false;
    long long     frames_  = 0;
    std::string   profile_;
    FrameCallback callback_;
    Fault         fault_ = Fault::None;
    std::map<std::string, std::string> features_;   // what setFeature() has set
};

}  // namespace fgc