-- SPDX-FileCopyrightText: © 2022—2026 Vladimir Zorin <vladimir@deviant.guru>
-- SPDX-License-Identifier: LicenseRef-OWL-1.0-or-later
-- Licensed under OWL v1.0+. See LICENSE.

local testimony = require("testimony")
local std = require("std")
local git = require("git")

local testify = testimony.new("== git (core) ==")

-- os.execute returns a boolean with LUA52COMPAT, a number otherwise
local sh = function(cmd)
	local r = os.execute(cmd .. " >/dev/null 2>&1")
	return r == true or r == 0
end

local has_git = sh("git --version")

local sh_out = function(cmd)
	local f = io.popen(cmd)
	if not f then
		return nil
	end
	local out = f:read("*a")
	f:close()
	return out and out:match("^%s*(.-)%s*$")
end

local make_fixture = function()
	local dir = "/tmp/" .. std.nanoid()
	local g = "git -C " .. dir .. " -c user.name=test -c user.email=test@test"
	if not sh("git init -q " .. dir) then
		return nil
	end
	std.fs.write_file(dir .. "/readme.txt", "hello lilush git core\n")
	std.fs.mkdir(dir .. "/sub")
	std.fs.write_file(dir .. "/sub/data.bin", string.rep("\0\1\2\3", 1024))
	sh(g .. " add -A")
	sh(g .. " commit -q -m first")
	std.fs.write_file(dir .. "/readme.txt", "hello again\n")
	sh(g .. " add -A")
	sh(g .. " commit -q -m second")
	sh(g .. " tag -a v1 -m release-one")
	local head = sh_out("git -C " .. dir .. " rev-parse HEAD")
	local head_ref = sh_out("git -C " .. dir .. " symbolic-ref HEAD")
	if not head or #head ~= 40 then
		return nil
	end
	return { dir = dir, git_dir = dir .. "/.git", head = head, head_ref = head_ref }
end

local fixture = has_git and make_fixture() or nil

if fixture then
	testify:that("find_git_dir: resolves from a subdirectory", function()
		local git_dir, worktree = git.find_git_dir(fixture.dir .. "/sub")
		testimony.assert_equal(fixture.git_dir, git_dir)
		testimony.assert_equal(fixture.dir, worktree)
	end)

	testify:that("read_head + resolve_ref: symbolic HEAD resolves to commit sha", function()
		local head = git.read_head(fixture.git_dir)
		testimony.assert_equal("branch", head.type)
		testimony.assert_equal(fixture.head_ref, head.ref)
		testimony.assert_equal(fixture.head, git.resolve_ref(fixture.git_dir, head.ref))
	end)

	testify:that("read_object: reads and types commit, tree, blob, tag", function()
		local commit_obj = git.read_object(fixture.git_dir, fixture.head)
		testimony.assert_equal("commit", commit_obj.type)
		local commit = git.parse_commit(commit_obj.content)
		testimony.assert_equal(1, #commit.parents)
		testimony.assert_match("second", commit.message)
		local tree_obj = git.read_object(fixture.git_dir, commit.tree)
		testimony.assert_equal("tree", tree_obj.type)
		local entries = git.parse_tree(tree_obj.content)
		testimony.assert_equal(2, #entries)
		local by_name = {}
		for _, e in ipairs(entries) do
			by_name[e.name] = e
		end
		testimony.assert_not_nil(by_name["readme.txt"])
		testimony.assert_equal("40000", by_name["sub"].mode)
		local blob = git.read_object(fixture.git_dir, by_name["readme.txt"].sha)
		testimony.assert_equal("blob", blob.type)
		testimony.assert_equal("hello again\n", blob.content)
	end)

	testify:that("flatten_tree: maps full paths to blob shas", function()
		local commit = git.parse_commit(git.read_object(fixture.git_dir, fixture.head).content)
		local files = git.flatten_tree(fixture.git_dir, commit.tree)
		testimony.assert_not_nil(files["readme.txt"])
		testimony.assert_not_nil(files["sub/data.bin"])
	end)

	testify:that("list_refs: finds branch, tag, and peeled tag", function()
		local refs = git.list_refs(fixture.git_dir)
		testimony.assert_equal(fixture.head, refs[fixture.head_ref])
		testimony.assert_not_nil(refs["refs/tags/v1"])
		testimony.assert_not_nil(refs["refs/tags/v1^{}"])
		testimony.assert_equal(fixture.head, refs["refs/tags/v1^{}"])
	end)

	testify:that("parse_index: reads the staging index", function()
		local entries = git.parse_index(fixture.git_dir)
		testimony.assert_equal(2, #entries)
		local names = {}
		for _, e in ipairs(entries) do
			names[e.name] = true
		end
		testimony.assert_true(names["readme.txt"])
		testimony.assert_true(names["sub/data.bin"])
	end)
else
	print("-- git binary not found (or fixture failed), skipping git core tests --")
end

if fixture then
	os.execute("rm -rf " .. fixture.dir)
end
testify:conclude()