#include <gtest/gtest.h>
#include "vde/brep/incremental_update.h"
#include "vde/brep/modeling.h"
#include "vde/brep/feature_tree.h"

using namespace vde::brep;
using namespace vde::core;

// Helper: create a FeatureHistory with an initial BrepModel
static FeatureHistory make_history() {
    FeatureHistory history;
    FeatureParams params;
    params.name = "box";
    params.values = {1.0, 1.0, 1.0};
    history.apply(make_box(1, 1, 1), FeatureType::PrimitiveBox, params);
    return history;
}

TEST(IncrementalUpdateTest, RegisterNode) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    EXPECT_EQ(engine.total_nodes(), 1);
}

TEST(IncrementalUpdateTest, RegisterWithDeps) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.register_node(2, {1});
    engine.register_node(3, {1, 2});
    EXPECT_EQ(engine.total_nodes(), 3);
}

TEST(IncrementalUpdateTest, MarkDirtyPropagates) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.register_node(2, {1});
    engine.register_node(3, {2});
    engine.mark_dirty(1);
    EXPECT_EQ(engine.dirty_count(), 3);
}

TEST(IncrementalUpdateTest, MarkDirtyNoUpstream) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.register_node(2, {1});
    engine.mark_dirty(2);
    EXPECT_EQ(engine.dirty_count(), 1);
}

TEST(IncrementalUpdateTest, CacheMissOnDirty) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.mark_dirty(1);
    EXPECT_TRUE(engine.get_cache(1) == nullptr);
    EXPECT_EQ(engine.cache_misses(), 1);
}

TEST(IncrementalUpdateTest, RebuildClearsDirty) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.mark_dirty(1);
    EXPECT_EQ(engine.dirty_count(), 1);

    auto history = make_history();
    engine.incremental_rebuild(history);
    EXPECT_EQ(engine.dirty_count(), 0);
}

TEST(IncrementalUpdateTest, RebuildWithCallback) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.mark_dirty(1);

    int cb = 0;
    auto history = make_history();
    engine.incremental_rebuild(history, [&](int nid, const BrepModel&) { cb++; });
    EXPECT_EQ(cb, 1);
}

TEST(IncrementalUpdateTest, RebuildClearsCacheDirty) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.mark_dirty(1);

    auto history = make_history();
    engine.incremental_rebuild(history);

    const auto* cache = engine.get_cache(1);
    ASSERT_TRUE(cache != nullptr);
    EXPECT_FALSE(cache->dirty);
    EXPECT_EQ(engine.cache_hits(), 1);
}

TEST(IncrementalUpdateTest, ChainDependencyOrder) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.register_node(2, {1});
    engine.mark_dirty(1);

    std::vector<int> order;
    auto history = make_history();
    engine.incremental_rebuild(history, [&](int nid, const BrepModel&) { order.push_back(nid); });
    ASSERT_GE(order.size(), 2u);
    // Node 1 must be rebuilt before node 2 (upstream before downstream)
    EXPECT_LT(std::find(order.begin(), order.end(), 1) - order.begin(),
              std::find(order.begin(), order.end(), 2) - order.begin());
}

TEST(IncrementalUpdateTest, IncrementalVsFull) {
    IncrementalUpdateEngine engine;
    for (int i = 1; i <= 10; ++i) {
        std::vector<int> deps;
        if (i > 1) deps.push_back(i - 1);
        engine.register_node(i, deps);
    }

    auto history = make_history();

    // Full rebuild (clear_all then rebuild)
    engine.clear_all();
    int fc = engine.incremental_rebuild(history);
    EXPECT_EQ(fc, 10);

    // Mark only node 5 dirty — should rebuild fewer nodes
    engine.clear_all();
    engine.incremental_rebuild(history);
    engine.mark_dirty(5);
    int ic = engine.incremental_rebuild(history);
    EXPECT_LT(ic, fc);
    EXPECT_GT(ic, 0);
}

TEST(IncrementalUpdateTest, InvalidateCachePropagates) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.register_node(2, {1});
    engine.register_node(3, {2});

    auto history = make_history();
    engine.incremental_rebuild(history); // build all
    EXPECT_EQ(engine.dirty_count(), 0);

    engine.invalidate_cache(1);
    // Node 1 and its dependents (2, 3) should all be dirty
    EXPECT_EQ(engine.dirty_count(), 3);
}

TEST(IncrementalUpdateTest, HitRate) {
    IncrementalUpdateEngine engine;
    // No cache access yet → 0 hit rate
    EXPECT_DOUBLE_EQ(engine.hit_rate(), 0.0);

    engine.register_node(1);
    // get_cache on dirty node → miss
    engine.mark_dirty(1);
    engine.get_cache(1);
    EXPECT_DOUBLE_EQ(engine.hit_rate(), 0.0);

    // After rebuild, get_cache should hit
    auto history = make_history();
    engine.incremental_rebuild(history);
    engine.get_cache(1);
    EXPECT_GT(engine.hit_rate(), 0.0);
}

TEST(IncrementalUpdateTest, ClearAllMarksAllDirty) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.register_node(2);

    auto history = make_history();
    engine.incremental_rebuild(history);
    EXPECT_EQ(engine.dirty_count(), 0);

    engine.clear_all();
    EXPECT_EQ(engine.dirty_count(), 2);
}

TEST(IncrementalUpdateTest, RebuildWithoutEvaluator) {
    IncrementalUpdateEngine engine;
    engine.register_node(1); // no evaluator registered (just topology)
    engine.mark_dirty(1);

    int cb = 0;
    auto history = make_history();
    engine.incremental_rebuild(history, [&](int, const BrepModel&) { cb++; });
    EXPECT_EQ(cb, 1); // callback still fires
    EXPECT_EQ(engine.dirty_count(), 0);
}

TEST(IncrementalUpdateTest, FullRebuild) {
    IncrementalUpdateEngine engine;
    engine.register_node(1);
    engine.register_node(2, {1});
    engine.register_node(3, {2});

    auto history = make_history();
    int count = engine.full_rebuild(history);
    EXPECT_EQ(count, 3);
    EXPECT_EQ(engine.dirty_count(), 0);
}