#include <doctest/doctest.h>

#include "fgc/CameraProfile.h"
#include "fgc/Hash.h"

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

#include <unistd.h>

using namespace fgc;
namespace fs = std::filesystem;

namespace {

fs::path scratch(const std::string& tag) {
    fs::path d = fs::temp_directory_path() / ("fgc_prof_" + tag + "_" + std::to_string(::getpid()));
    fs::remove_all(d);
    fs::create_directories(d);
    return d;
}

std::string xmlWith(const std::string& rate) {
    return
        "<ModuleSettings><CameraInfo Id=\"DEV_1\" Model=\"1800 U-2040c\">"
        "<RemoteDevice>"
        "<Feature Name=\"AcquisitionFrameRate\" Value=\"" + rate + "\" Type=\"Float\" />"
        "<Feature Name=\"Gamma\" Value=\"1\" Type=\"Float\" />"
        "</RemoteDevice></CameraInfo></ModuleSettings>";
}

void write(const fs::path& p, const std::string& text) {
    std::ofstream f(p, std::ios::binary);
    f << text;
}

}  // namespace

TEST_CASE("loadCameraProfile generates the record on first load") {
    fs::path d = scratch("first");
    write(d / "standard.xml", xmlWith("10"));

    ProfileLoadResult r;
    CameraProfile p = loadCameraProfile(d.string(), "standard", r);

    CHECK(p.name == "standard");
    CHECK(p.xml_path == (d / "standard.xml").string());
    CHECK(p.txt_path == (d / "standard.txt").string());
    CHECK(fs::is_regular_file(p.txt_path));
    CHECK(p.settings.entries.size() == 2);
    // A first load has no baseline: reporting every setting as "new" would be
    // thousands of lines and no information for a real export.
    CHECK(r.regenerated);
    CHECK(r.first_run);
    CHECK(r.changes.empty());

    // The record carries the hash of the XML it came from.
    SettingsRecord rec = readSettingsRecord(p.txt_path);
    CHECK(rec.hash_label == hashLabel(fnv1a64File(p.xml_path)));

    fs::remove_all(d);
}

TEST_CASE("an unchanged XML is not regenerated and reports no changes") {
    fs::path d = scratch("stable");
    write(d / "standard.xml", xmlWith("10"));

    ProfileLoadResult r;
    loadCameraProfile(d.string(), "standard", r);
    const auto stamp = fs::last_write_time(d / "standard.txt");

    loadCameraProfile(d.string(), "standard", r);
    CHECK_FALSE(r.regenerated);
    CHECK(r.changes.empty());
    // Untouched: a rewrite every startup would churn the file and its timestamp.
    CHECK(fs::last_write_time(d / "standard.txt") == stamp);

    fs::remove_all(d);
}

TEST_CASE("a changed XML regenerates the record and names what moved") {
    fs::path d = scratch("changed");
    write(d / "standard.xml", xmlWith("10"));
    ProfileLoadResult r;
    loadCameraProfile(d.string(), "standard", r);

    write(d / "standard.xml", xmlWith("8"));
    CameraProfile p = loadCameraProfile(d.string(), "standard", r);

    CHECK(r.regenerated);
    CHECK_FALSE(r.first_run);   // there WAS a baseline, so this is a real change
    REQUIRE(r.changes.size() == 1);
    CHECK(r.changes[0].find("AcquisitionFrameRate") != std::string::npos);
    CHECK(r.changes[0].find("10 -> 8") != std::string::npos);

    // And the record now matches the new XML.
    SettingsRecord rec = readSettingsRecord(p.txt_path);
    CHECK(rec.hash_label == hashLabel(fnv1a64File(p.xml_path)));

    fs::remove_all(d);
}

TEST_CASE("a missing XML throws - the record is never a fallback") {
    fs::path d = scratch("missing");
    // A record on its own must not make the profile loadable: it is a record, not
    // a configuration source, and applying one would defeat the GUI validation
    // that the XML exists to guarantee.
    write(d / "standard.txt", "[Source]\nxml_hash = fnv1a64:0000000000000000\n[Settings]\nGamma = 1\n");

    ProfileLoadResult r;
    CHECK_THROWS(loadCameraProfile(d.string(), "standard", r));

    fs::remove_all(d);
}

TEST_CASE("loadCameraProfiles picks up every *.xml and fails loudly when there are none") {
    fs::path d = scratch("dir");
    std::map<std::string, ProfileLoadResult> results;

    CHECK_THROWS(loadCameraProfiles(d.string(), results));            // empty directory
    CHECK_THROWS(loadCameraProfiles((d / "nope").string(), results)); // missing directory

    write(d / "standard.xml", xmlWith("10"));
    write(d / "night.xml", xmlWith("1"));
    write(d / "notes.md", "not a profile");

    auto profiles = loadCameraProfiles(d.string(), results);
    CHECK(profiles.size() == 2);
    CHECK(profiles.count("standard") == 1);
    CHECK(profiles.count("night") == 1);
    CHECK(profiles.count("notes") == 0);
    // Both were written for the first time, and neither reports a change.
    REQUIRE(results.size() == 2);
    for (const auto& [name, r] : results) {
        CHECK(r.first_run);
        CHECK(r.changes.empty());
    }

    // One bad profile fails the whole load, so a profile nobody uses today cannot
    // rot unnoticed until the night someone switches to it.
    write(d / "broken.xml", "<ModuleSettings></ModuleSettings>");
    CHECK_THROWS(loadCameraProfiles(d.string(), results));

    fs::remove_all(d);
}