#include "catch.hpp"

#include <algorithm>
#include <filesystem>
#include <fstream>
#include <stdexcept>
#include <string>
#include <system_error>

#include "BuildingType.h"
#include "ConfigLoader.h"

namespace
{

// Writes content to a file at path; creates parent directories if needed.
// Used to materialize malformed TOML for error-path coverage.
void writeFile(const std::filesystem::path& path, const std::string& content)
{
    std::filesystem::create_directories(path.parent_path());
    std::ofstream out(path);
    out << content;
}

// RAII temp directory: allocated in ctor, recursively removed in dtor.
class TempConfigDir
{
public:
    TempConfigDir()
    {
        const std::filesystem::path base = std::filesystem::temp_directory_path();
        for (int i = 0; i < 10000; ++i)
        {
            const std::filesystem::path candidate =
                base / ("dota_factory_test_" + std::to_string(i) + "_"
                        + std::to_string(reinterpret_cast<std::uintptr_t>(this)));
            if (!std::filesystem::exists(candidate))
            {
                std::filesystem::create_directories(candidate);
                m_path = candidate;
                return;
            }
        }
        throw std::runtime_error("Could not allocate temp directory for test");
    }

    ~TempConfigDir()
    {
        std::error_code ec;
        std::filesystem::remove_all(m_path, ec);
    }

    TempConfigDir(const TempConfigDir&) = delete;
    TempConfigDir& operator=(const TempConfigDir&) = delete;

    const std::filesystem::path& path() const { return m_path; }

private:
    std::filesystem::path m_path;
};

} // namespace


TEST_CASE("ConfigLoader loads the committed bin/config/ configs end-to-end", "[config]")
{
    const std::string configDir = CONFIG_DIR;
    const GameConfig cfg = ConfigLoader::loadFromDirectory(configDir);

    // world.toml
    REQUIRE(cfg.world.heightTiles == 60);
    REQUIRE(cfg.world.refundPercentage == 75);
    REQUIRE(cfg.world.beltSpeedTilesPerSecond == Approx(2.0));
    REQUIRE(cfg.world.regions.asteroidWidth == 40);
    REQUIRE(cfg.world.regions.playerBufferWidth == 10);
    REQUIRE(cfg.world.regions.enemyBufferWidth == 15);
    REQUIRE(cfg.world.expansion.columnsPerExpansion == 10);
    REQUIRE(cfg.world.push.scalingFactor == Approx(1.2));

    // Spot-check that a config-derived formula computes as expected.
    // threat_rate_formula = "1*x - 30": zero at x=30, 30 at x=60.
    REQUIRE(cfg.world.waves.threatRateFormula.evaluate(30.0) == Approx(0.0));
    REQUIRE(cfg.world.waves.threatRateFormula.evaluate(60.0) == Approx(30.0));

    // buildings.toml
    REQUIRE(cfg.buildings.buildings.size() >= 8);
    const auto minerIt = std::find_if(
        cfg.buildings.buildings.begin(), cfg.buildings.buildings.end(),
        [](const BuildingDef& b) { return b.type == BuildingType::Miner; });
    REQUIRE(minerIt != cfg.buildings.buildings.end());
    REQUIRE(minerIt->cost == 15);
    REQUIRE(minerIt->surfaceMask.size() == 2);

    // recipes.toml — reprocessing cycle has three weighted outputs.
    const auto reproIt = std::find_if(
        cfg.recipes.recipes.begin(), cfg.recipes.recipes.end(),
        [](const RecipeDef& r) { return r.id == "reprocessing_cycle"; });
    REQUIRE(reproIt != cfg.recipes.recipes.end());
    REQUIRE(reproIt->building == BuildingType::ReprocessingPlant);
    REQUIRE(reproIt->outputs.size() == 3);
    REQUIRE(reproIt->outputs[0].probability.has_value());

    // Non-reprocessing recipes don't carry probability.
    const auto ironIngotIt = std::find_if(
        cfg.recipes.recipes.begin(), cfg.recipes.recipes.end(),
        [](const RecipeDef& r) { return r.id == "iron_ingot"; });
    REQUIRE(ironIngotIt != cfg.recipes.recipes.end());
    REQUIRE(ironIngotIt->outputs.size() == 1);
    REQUIRE_FALSE(ironIngotIt->outputs[0].probability.has_value());

    // ships.toml — combat ships have default_modules with a weapon; salvage ships don't.
    const auto interceptorIt = std::find_if(
        cfg.ships.ships.begin(), cfg.ships.ships.end(),
        [](const ShipDef& s) { return s.id == "interceptor"; });
    REQUIRE(interceptorIt != cfg.ships.ships.end());
    REQUIRE_FALSE(interceptorIt->defaultModules.empty());
    REQUIRE(interceptorIt->defaultModules[0].moduleId == "laser_cannon");

    const auto salvageShipIt = std::find_if(
        cfg.ships.ships.begin(), cfg.ships.ships.end(),
        [](const ShipDef& s) { return s.id == "salvage_ship"; });
    REQUIRE(salvageShipIt != cfg.ships.ships.end());
    REQUIRE(salvageShipIt->defaultModules.empty());

    // stations.toml
    REQUIRE(cfg.stations.playerStation.level == 5);
    REQUIRE(cfg.stations.playerStation.hpFormula.evaluate(5.0) == Approx(500.0));  // 300 + 40*5
    REQUIRE(cfg.stations.enemyStation.hpFormula.evaluate(0.0) == Approx(300.0));   // 300 + 150*0
}

TEST_CASE("Loading a non-existent file throws", "[config]")
{
    REQUIRE_THROWS(ConfigLoader::loadWorld("does/not/exist.toml"));
}

TEST_CASE("Malformed TOML is rejected with a file-identifying message", "[config]")
{
    TempConfigDir dir;
    writeFile(dir.path() / "world.toml", "this is = not [ valid toml\n");

    try
    {
        ConfigLoader::loadWorld((dir.path() / "world.toml").string());
        FAIL("Expected exception");
    }
    catch (const std::runtime_error& e)
    {
        const std::string msg = e.what();
        REQUIRE(msg.find("world.toml") != std::string::npos);
    }
}

TEST_CASE("Missing field in world.toml is rejected with the field path", "[config]")
{
    TempConfigDir dir;
    writeFile(dir.path() / "world.toml", R"(
[world]
height_tiles = 60
refund_percentage = 75
scrap_despawn_seconds = 30
belt_speed_tiles_per_second = 2
starting_building_blocks = 100
tunnel_max_distance = 10
departure_interval_seconds = 20

[regions]
asteroid_width = 40
player_buffer_width = 10
contest_zone_width = 30
# enemy_buffer_width intentionally missing

[expansion]
columns_per_expansion = 10
cost_building_blocks = 200

[push]
push_expand_columns = 20
scaling_factor = 1.2

[waves]
threat_rate_formula = "1*x - 30"
ship_level_formula = "1 + x / 120"
gap_min_seconds = 15
gap_max_seconds = 45
spawn_duration_seconds = 10
)");

    try
    {
        ConfigLoader::loadWorld((dir.path() / "world.toml").string());
        FAIL("Expected exception");
    }
    catch (const std::runtime_error& e)
    {
        const std::string msg = e.what();
        REQUIRE(msg.find("enemy_buffer_width") != std::string::npos);
    }
}

TEST_CASE("Malformed formula in world.toml is rejected with field identification", "[config]")
{
    TempConfigDir dir;
    writeFile(dir.path() / "world.toml", R"(
[world]
height_tiles = 60
refund_percentage = 75
scrap_despawn_seconds = 30
belt_speed_tiles_per_second = 2
starting_building_blocks = 100
tunnel_max_distance = 10
departure_interval_seconds = 20

[regions]
asteroid_width = 40
player_buffer_width = 10
contest_zone_width = 30
enemy_buffer_width = 15

[expansion]
columns_per_expansion = 10
cost_building_blocks = 200

[push]
push_expand_columns = 20
scaling_factor = 1.2

[waves]
threat_rate_formula = "1 +"
ship_level_formula = "1 + x / 120"
gap_min_seconds = 15
gap_max_seconds = 45
spawn_duration_seconds = 10
)");

    try
    {
        ConfigLoader::loadWorld((dir.path() / "world.toml").string());
        FAIL("Expected exception");
    }
    catch (const std::runtime_error& e)
    {
        const std::string msg = e.what();
        REQUIRE(msg.find("threat_rate_formula") != std::string::npos);
        REQUIRE(msg.find("formula") != std::string::npos);
    }
}

TEST_CASE("Inverted wave gap range is rejected", "[config]")
{
    TempConfigDir dir;
    writeFile(dir.path() / "world.toml", R"(
[world]
height_tiles = 60
refund_percentage = 75
scrap_despawn_seconds = 30
belt_speed_tiles_per_second = 2

[regions]
asteroid_width = 40
player_buffer_width = 10
contest_zone_width = 30
enemy_buffer_width = 15

[expansion]
columns_per_expansion = 10
cost_building_blocks = 200

[push]
push_expand_columns = 20
scaling_factor = 1.2

[waves]
threat_rate_formula = "1*x - 30"
ship_level_formula = "1 + x / 120"
gap_min_seconds = 45
gap_max_seconds = 15
spawn_duration_seconds = 10
)");

    REQUIRE_THROWS_AS(
        ConfigLoader::loadWorld((dir.path() / "world.toml").string()),
        std::runtime_error);
}

TEST_CASE("Unknown building id in buildings.toml is rejected with the id in the message", "[config]")
{
    TempConfigDir dir;
    writeFile(dir.path() / "buildings.toml", R"(
[[building]]
id = "fictional_machine"
cost = 10
player_placeable = true
construction_time_seconds = 5
surface_mask = ["AA"]
)");

    try
    {
        ConfigLoader::loadBuildings((dir.path() / "buildings.toml").string());
        FAIL("Expected exception");
    }
    catch (const std::runtime_error& e)
    {
        const std::string msg = e.what();
        REQUIRE(msg.find("fictional_machine") != std::string::npos);
    }
}

TEST_CASE("Recipe referencing an unknown building is rejected", "[config]")
{
    TempConfigDir dir;
    writeFile(dir.path() / "recipes.toml", R"(
[[recipe]]
id = "bogus"
building = "imaginary_factory"
inputs = []
outputs = [{item = "foo", amount = 1}]
duration_seconds = 1.0
)");

    REQUIRE_THROWS_AS(
        ConfigLoader::loadRecipes((dir.path() / "recipes.toml").string()),
        std::runtime_error);
}