#include <gtest/gtest.h>

#include "panels/chart/ContourSimplify.hpp"

using geopro::app::douglasPeucker;
using geopro::core::Vec2;

TEST(ContourSimplify, TolZeroReturnsOriginal) {
    std::vector<Vec2> pts{{0, 0}, {1, 0.01}, {2, 0}};
    auto out = douglasPeucker(pts, 0.0);
    EXPECT_EQ(out.size(), 3u);
}

TEST(ContourSimplify, ShortPolylineUnchanged) {
    std::vector<Vec2> pts{{0, 0}, {5, 5}};
    auto out = douglasPeucker(pts, 1.0);
    EXPECT_EQ(out.size(), 2u);  // 点数<=2 原样
}

TEST(ContourSimplify, CollinearMiddleDropped) {
    // 共线点：中点在容差内 → 被抽掉，只保留首尾。
    std::vector<Vec2> pts{{0, 0}, {1, 0}, {2, 0}, {3, 0}};
    auto out = douglasPeucker(pts, 0.1);
    ASSERT_EQ(out.size(), 2u);
    EXPECT_DOUBLE_EQ(out.front().x, 0.0);
    EXPECT_DOUBLE_EQ(out.back().x, 3.0);
}

TEST(ContourSimplify, SignificantPointKept) {
    // 中间有明显偏移的点（偏 1.0 > tol 0.5）→ 保留。
    std::vector<Vec2> pts{{0, 0}, {1, 1.0}, {2, 0}};
    auto out = douglasPeucker(pts, 0.5);
    EXPECT_EQ(out.size(), 3u);
}

TEST(ContourSimplify, LargerTolDropsMorePoints) {
    std::vector<Vec2> pts{{0, 0}, {1, 0.2}, {2, 0}, {3, 0.2}, {4, 0}};
    auto coarse = douglasPeucker(pts, 0.5);   // 偏移 0.2 < 0.5 → 全抽成首尾
    auto fine = douglasPeucker(pts, 0.05);    // 0.2 > 0.05 → 保留中间峰
    EXPECT_LT(coarse.size(), fine.size());
    EXPECT_EQ(coarse.size(), 2u);
}