#include <gtest/gtest.h>

import std;

import mcpp.build.graph_shape;

// The header line build.ninja carries is what the fast paths read before any

// plan exists. Four facts ride it -- the graph's shape, the module-edge

// schedule, (2026.9.5.3+) whether a `--accel` / `--no-accel` override chose

// the device variant, and (2026.9.11.1+) which distribution format the graph

// was generated for -- and the fast paths decline a graph that says anything

// other than "plain build, manifest's own variant, no distribution edge".

//

// THE FOURTH FIELD IS VERIFIED HERE AND NOT ONLY END TO END, deliberately.

// `mcpp pack --format <name>` prepares twice and the second pass writes its

// graph into the SAME fingerprint directory a plain build uses, because the

// format is not in the fingerprint. Measured on 2026-09-11: a plain build

// after that pass regenerates the graph even with this field ignored, so some

// earlier freshness condition already declines -- which means an end-to-end

// assertion would pass whether or not the field works, and would keep passing

// if the field were deleted. A read-side invariant only has to hold once

// (see the module header); this is where it is held.

namespace {

std::filesystem::path write_graph(const std::string& first) {

static const auto run = std::random_device{}();

auto dir = std::filesystem::temp_directory_path()

/ ("mcpp-graph-shape-" + std::to_string(run) + "-"

+ std::to_string(std::hash<std::string>{}(first)));

std::filesystem::create_directories(dir);

auto p = dir / "build.ninja";

std::ofstream os(p, std::ios::trunc);

os << "# Auto-generated by mcpp v0.0.1. Do not edit by hand.\n"

<< first << "\n"

<< "ninja_required_version = 1.11\n";

return p;

}

} // namespace

TEST(GraphShape, TheHeaderNamesShapeScheduleSelectionAndFormat) {

EXPECT_EQ(mcpp::build::header_line(mcpp::build::GraphShape::Normal, "none", false),

"# mcpp:graph=normal;schedule=none;accel=default;dist=none");

EXPECT_EQ(mcpp::build::header_line(mcpp::build::GraphShape::WithTests, "two-phase", true),

"# mcpp:graph=test;schedule=two-phase;accel=override;dist=none");

// An empty format reads as "none" rather than as an empty field: the value

// has to be a word, because `read_pack_format` returning "" already means

// "this file predates the field", and the two must not collide.

EXPECT_EQ(mcpp::build::header_line(mcpp::build::GraphShape::Normal, "none", false, "appimage"),

"# mcpp:graph=normal;schedule=none;accel=default;dist=appimage");

}

TEST(GraphShape, OnlyAPlainGraphWithTheManifestsVariantIsReplayed) {

using namespace mcpp::build;

EXPECT_TRUE(is_plain_build_graph(write_graph(header_line(GraphShape::Normal, "none", false))));

// An override chose this variant: a plain build must not replay it.

EXPECT_FALSE(is_plain_build_graph(write_graph(header_line(GraphShape::Normal, "none", true))));

// The test-shaped graph was already refused.

EXPECT_FALSE(is_plain_build_graph(write_graph(header_line(GraphShape::WithTests, "none", false))));

// A DISTRIBUTION EDGE IS NOT PART OF A PLAIN BUILD. `mcpp pack --format

// appimage` makes a build program submit an artifact action consuming the

// staged tree; replaying that graph for a plain build would produce a

// distributable as a side effect of `mcpp build`, from a staged tree that

// is no longer guaranteed to describe this build.

EXPECT_FALSE(is_plain_build_graph(

write_graph(header_line(GraphShape::Normal, "none", false, "appimage"))));

EXPECT_EQ(read_pack_format(

write_graph(header_line(GraphShape::Normal, "none", false, "appimage"))),

"appimage");

EXPECT_EQ(read_pack_format(

write_graph(header_line(GraphShape::Normal, "none", false))),

"none");

}

TEST(GraphShape, AGraphThatPredatesTheFieldIsAMiss) {

using namespace mcpp::build;

// Written by a 2026.9.5.2 mcpp: shape and schedule, no selection. It is

// not known to be the manifest's variant, so it is prepared once more and

// rewritten with the field -- a miss, never a guess.

auto p = write_graph("# mcpp:graph=normal;schedule=none");

EXPECT_EQ(read_shape(p), GraphShape::Normal);

EXPECT_EQ(read_accel_selection(p), "");

EXPECT_EQ(read_pack_format(p), "");

EXPECT_FALSE(is_plain_build_graph(p));

// Written by a 2026.9.10.2 mcpp: shape, schedule and selection, no

// distribution field. Same rule one field later -- absent is a miss, and

// must not be read as "none", or the very first build after an upgrade

// would replay a graph this binary cannot describe.

auto q = write_graph("# mcpp:graph=normal;schedule=none;accel=default");

EXPECT_EQ(read_accel_selection(q), "default");

EXPECT_EQ(read_pack_format(q), "");

EXPECT_FALSE(is_plain_build_graph(q));

}