#include "ScriptRuntime.h"
#include "SceneObject.h"
#include "ThirdParty/imgui/imgui.h"
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>

namespace {
struct Keyframe {
    float time = 0.0f;
    glm::vec3 position = glm::vec3(0.0f);
    glm::vec3 rotation = glm::vec3(0.0f);
    glm::vec3 scale = glm::vec3(1.0f);
};

int targetId = -1;
char targetName[128] = "";
std::vector<Keyframe> keyframes;
int selectedKey = -1;

float clipLength = 2.0f;
float currentTime = 0.0f;
float playSpeed = 1.0f;
bool isPlaying = false;
bool loop = true;
bool applyOnScrub = true;

glm::vec3 lerpVec3(const glm::vec3& a, const glm::vec3& b, float t) {
    return a + (b - a) * t;
}

float clampFloat(float value, float minValue, float maxValue) {
    return std::max(minValue, std::min(value, maxValue));
}

SceneObject* resolveTarget(ScriptContext& ctx) {
    if (targetId >= 0) {
        if (auto* obj = ctx.FindObjectById(targetId)) {
            return obj;
        }
    }
    if (targetName[0] != '\0') {
        if (auto* obj = ctx.FindObjectByName(targetName)) {
            targetId = obj->id;
            return obj;
        }
    }
    return nullptr;
}

void syncTargetLabel(SceneObject* obj) {
    if (!obj) return;
    strncpy(targetName, obj->name.c_str(), sizeof(targetName) - 1);
    targetName[sizeof(targetName) - 1] = '\0';
}

void captureKeyframe(SceneObject& obj, float time) {
    float clamped = clampFloat(time, 0.0f, clipLength);
    auto it = std::find_if(keyframes.begin(), keyframes.end(),
                           [&](const Keyframe& k) { return std::abs(k.time - clamped) < 0.0001f; });
    if (it == keyframes.end()) {
        keyframes.push_back(Keyframe{clamped, obj.position, obj.rotation, obj.scale});
    } else {
        it->position = obj.position;
        it->rotation = obj.rotation;
        it->scale = obj.scale;
    }
    std::sort(keyframes.begin(), keyframes.end(),
              [](const Keyframe& a, const Keyframe& b) { return a.time < b.time; });
}

void deleteKeyframe(int index) {
    if (index < 0 || index >= static_cast<int>(keyframes.size())) return;
    keyframes.erase(keyframes.begin() + index);
    if (selectedKey == index) selectedKey = -1;
    if (selectedKey > index) selectedKey--;
}

void applyPoseAtTime(ScriptContext& ctx, SceneObject& obj, float time) {
    if (keyframes.empty()) return;

    if (time <= keyframes.front().time) {
        ctx.SetPosition(keyframes.front().position);
        ctx.SetRotation(keyframes.front().rotation);
        ctx.SetScale(keyframes.front().scale);
        ctx.MarkDirty();
        return;
    }
    if (time >= keyframes.back().time) {
        ctx.SetPosition(keyframes.back().position);
        ctx.SetRotation(keyframes.back().rotation);
        ctx.SetScale(keyframes.back().scale);
        ctx.MarkDirty();
        return;
    }

    for (size_t i = 0; i + 1 < keyframes.size(); ++i) {
        const Keyframe& a = keyframes[i];
        const Keyframe& b = keyframes[i + 1];
        if (time >= a.time && time <= b.time) {
            float span = b.time - a.time;
            float t = (span > 0.0f) ? (time - a.time) / span : 0.0f;
            ctx.SetPosition(lerpVec3(a.position, b.position, t));
            ctx.SetRotation(lerpVec3(a.rotation, b.rotation, t));
            ctx.SetScale(lerpVec3(a.scale, b.scale, t));
            ctx.MarkDirty();
            return;
        }
    }
}

void drawTimeline(float& time, float length, int& selection) {
    ImVec2 size = ImVec2(ImGui::GetContentRegionAvail().x, 70.0f);
    ImVec2 start = ImGui::GetCursorScreenPos();
    ImGui::InvisibleButton("Timeline", size);

    ImDrawList* draw = ImGui::GetWindowDrawList();
    ImU32 bg = ImGui::GetColorU32(ImGuiCol_FrameBg);
    ImU32 border = ImGui::GetColorU32(ImGuiCol_Border);
    ImU32 accent = ImGui::GetColorU32(ImGuiCol_CheckMark);
    ImU32 keyColor = ImGui::GetColorU32(ImGuiCol_SliderGrab);

    draw->AddRectFilled(start, ImVec2(start.x + size.x, start.y + size.y), bg, 6.0f);
    draw->AddRect(start, ImVec2(start.x + size.x, start.y + size.y), border, 6.0f);

    float clamped = clampFloat(time, 0.0f, length);
    float playheadX = start.x + (length > 0.0f ? (clamped / length) * size.x : 0.0f);
    draw->AddLine(ImVec2(playheadX, start.y), ImVec2(playheadX, start.y + size.y), accent, 2.0f);

    for (size_t i = 0; i < keyframes.size(); ++i) {
        float keyX = start.x + (length > 0.0f ? (keyframes[i].time / length) * size.x : 0.0f);
        ImVec2 center(keyX, start.y + size.y * 0.5f);
        float radius = (selection == static_cast<int>(i)) ? 6.0f : 4.5f;
        draw->AddCircleFilled(center, radius, keyColor);
        ImRect hit(ImVec2(center.x - 7.0f, center.y - 7.0f), ImVec2(center.x + 7.0f, center.y + 7.0f));
        if (ImGui::IsMouseHoveringRect(hit.Min, hit.Max) && ImGui::IsMouseClicked(ImGuiMouseButton_Left)) {
            selection = static_cast<int>(i);
            time = keyframes[i].time;
        }
    }

    if (ImGui::IsItemActive() && ImGui::IsMouseClicked(ImGuiMouseButton_Left)) {
        float mouseX = ImGui::GetIO().MousePos.x;
        float t = (mouseX - start.x) / size.x;
        time = clampFloat(t * length, 0.0f, length);
    }
}

void drawKeyframeTable() {
    if (keyframes.empty()) {
        ImGui::TextDisabled("No keyframes yet.");
        return;
    }

    if (ImGui::BeginTable("KeyframeTable", 4, ImGuiTableFlags_Borders | ImGuiTableFlags_RowBg | ImGuiTableFlags_SizingFixedFit)) {
        ImGui::TableSetupColumn("Time");
        ImGui::TableSetupColumn("Position");
        ImGui::TableSetupColumn("Rotation");
        ImGui::TableSetupColumn("Scale");
        ImGui::TableHeadersRow();

        for (size_t i = 0; i < keyframes.size(); ++i) {
            const auto& key = keyframes[i];
            ImGui::TableNextRow();
            ImGui::TableNextColumn();
            bool selected = selectedKey == static_cast<int>(i);
            std::string label = std::to_string(key.time);
            if (ImGui::Selectable(label.c_str(), selected, ImGuiSelectableFlags_SpanAllColumns)) {
                selectedKey = static_cast<int>(i);
                currentTime = key.time;
            }
            ImGui::TableNextColumn();
            ImGui::Text("%.2f, %.2f, %.2f", key.position.x, key.position.y, key.position.z);
            ImGui::TableNextColumn();
            ImGui::Text("%.2f, %.2f, %.2f", key.rotation.x, key.rotation.y, key.rotation.z);
            ImGui::TableNextColumn();
            ImGui::Text("%.2f, %.2f, %.2f", key.scale.x, key.scale.y, key.scale.z);
        }
        ImGui::EndTable();
    }
}
} // namespace

extern "C" void RenderEditorWindow(ScriptContext& ctx) {
    ImGui::TextUnformatted("Simple Animation");
    ImGui::Separator();

    SceneObject* selectedObj = ctx.object;
    SceneObject* targetObj = resolveTarget(ctx);

    ImGui::TextDisabled("Select a GameObject to animate:");
    ImGui::BeginDisabled();
    ImGui::InputText("##TargetName", targetName, sizeof(targetName));
    ImGui::EndDisabled();
    ImGui::SameLine();
    if (ImGui::Button("Use Selected") && selectedObj) {
        targetId = selectedObj->id;
        syncTargetLabel(selectedObj);
    }
    ImGui::SameLine();
    if (ImGui::Button("Clear")) {
        targetId = -1;
        targetName[0] = '\0';
        targetObj = nullptr;
    }

    ImGui::Spacing();
    if (ImGui::BeginTabBar("AnimModeTabs")) {
        if (ImGui::BeginTabItem("Pose Mode")) {
            ImGui::TextDisabled("Pose Editor");
            ImGui::Separator();

            ImGui::PushStyleVar(ImGuiStyleVar_FrameRounding, 6.0f);
            if (ImGui::Button("Key")) {
                if (targetObj) captureKeyframe(*targetObj, currentTime);
            }
            ImGui::SameLine();
            if (ImGui::Button("Delete") && selectedKey >= 0) {
                deleteKeyframe(selectedKey);
            }
            ImGui::PopStyleVar();

            ImGui::Spacing();
            drawTimeline(currentTime, clipLength, selectedKey);
            ImGui::SliderFloat("Time", &currentTime, 0.0f, clipLength, "%.2fs");

            ImGui::Spacing();
            drawKeyframeTable();

            ImGui::EndTabItem();
        }
        if (ImGui::BeginTabItem("Config Mode")) {
            ImGui::TextDisabled("Playback");
            ImGui::Separator();
            ImGui::Checkbox("Loop", &loop);
            ImGui::Checkbox("Apply On Scrub", &applyOnScrub);
            ImGui::SliderFloat("Length", &clipLength, 0.1f, 20.0f, "%.2fs");
            ImGui::SliderFloat("Speed", &playSpeed, 0.1f, 4.0f, "%.2fx");
            ImGui::EndTabItem();
        }
        ImGui::EndTabBar();
    }

    ImGui::Spacing();
    ImGui::Separator();
    ImGui::TextDisabled("Transport");
    if (ImGui::Button(isPlaying ? "Pause" : "Play")) {
        isPlaying = !isPlaying;
    }
    ImGui::SameLine();
    if (ImGui::Button("Stop")) {
        isPlaying = false;
        currentTime = 0.0f;
    }

    if (targetObj) {
        ImGui::SameLine();
        ImGui::TextDisabled("Target: %s", targetObj->name.c_str());
    } else {
        ImGui::TextDisabled("No target selected.");
    }

    if (isPlaying && clipLength > 0.0f) {
        currentTime += ImGui::GetIO().DeltaTime * playSpeed;
        if (currentTime > clipLength) {
            if (loop) currentTime = std::fmod(currentTime, clipLength);
            else {
                currentTime = clipLength;
                isPlaying = false;
            }
        }
    }

    if (targetObj && (isPlaying || applyOnScrub)) {
        applyPoseAtTime(ctx, *targetObj, currentTime);
    }
}

extern "C" void ExitRenderEditorWindow(ScriptContext& ctx) {
    (void)ctx;
}