-- 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.

--[[
Throwaway git fixture for lilgit tests, built with the real git binary.

`make()` creates a root directory holding two repositories:

  root/fix       worktree repo (loose objects/refs), registry name "fix"
  root/bare.git  gc'd bare clone (packed objects + packed-refs with
                 peeled tag lines), registry name "bare"

Contents: a README with a relative image link, a binary image, Lua
source, a markdown subdirectory doc, a plain unknown-extension file, a
symlink, a slashed branch `feature/foo`, and an annotated tag `v1.0`.
]]

local std = require("std")

-- 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 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 has_git = function()
	return sh("git --version")
end

local PNG_BYTES = "\137PNG\r\n\26\n" .. string.rep("\0\1\2\3", 16)

local make = function()
	local root = "/tmp/lilgit-fix-" .. std.nanoid()
	local dir = root .. "/fix"
	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.md", "# Fixture Repo\n\nSome intro text.\n\n![logo](assets/logo.png)\n")
	std.fs.mkdir(dir .. "/assets")
	std.fs.write_file(dir .. "/assets/logo.png", PNG_BYTES)
	std.fs.mkdir(dir .. "/src")
	std.fs.write_file(dir .. "/src/main.lua", 'print("hello from fixture")\n')
	std.fs.mkdir(dir .. "/docs")
	std.fs.write_file(dir .. "/docs/guide.md", "# Guide\n\nBack to the [readme](../README.md).\n")
	std.fs.write_file(dir .. "/plain.xyz", "just some text in an unknown extension\n")
	sh("ln -s README.md " .. dir .. "/link.md")
	sh(g .. " add -A")
	if not sh(g .. " commit -q -m first") then
		return nil
	end
	local branch = sh_out("git -C " .. dir .. " symbolic-ref --short HEAD")
	local head = sh_out("git -C " .. dir .. " rev-parse HEAD")
	sh(g .. " checkout -q -b feature/foo")
	std.fs.write_file(dir .. "/feature.txt", "feature branch file\n")
	sh(g .. " add -A")
	sh(g .. " commit -q -m feature")
	local feature = sh_out("git -C " .. dir .. " rev-parse HEAD")
	sh(g .. " checkout -q " .. branch)
	sh(g .. " tag -a v1.0 -m release")
	local tag = sh_out("git -C " .. dir .. " rev-parse v1.0")
	local tag_commit = sh_out("git -C " .. dir .. " rev-parse v1.0^{}")
	local readme_blob = sh_out("git -C " .. dir .. " rev-parse " .. branch .. ":README.md")
	sh(g .. " gc -q")
	if not sh("git clone -q --bare " .. dir .. " " .. root .. "/bare.git") then
		return nil
	end
	sh("git -C " .. root .. "/bare.git gc -q")
	sh("git -C " .. root .. "/bare.git pack-refs --all")
	if not head or #head ~= 40 or not branch then
		return nil
	end
	return {
		root = root,
		dir = dir,
		git_dir = dir .. "/.git",
		bare_dir = root .. "/bare.git",
		branch = branch,
		head = head,
		feature = feature,
		tag = tag,
		tag_commit = tag_commit,
		readme_blob = readme_blob,
	}
end

local destroy = function(fx)
	if fx and fx.root and fx.root:match("^/tmp/lilgit%-fix%-") then
		sh("rm -rf " .. fx.root)
	end
end

return {
	has_git = has_git,
	make = make,
	destroy = destroy,
	sh = sh,
	sh_out = sh_out,
}