local function system(v) return vim.api.nvim_call_function('system', { v }) end
local function systemlist(v) return vim.api.nvim_call_function('systemlist', { v }) end

local function is_git_repo()
    local is_git = system('git rev-parse')
    return string.match(is_git, 'fatal') == nil
end

local IS_GIT_REPO = is_git_repo()

local function set_git_status()
    if IS_GIT_REPO == false then return '' end
    return systemlist('git status --porcelain=v1')
end

local GIT_STATUS = set_git_status()

local function refresh_git()
    if IS_GIT_REPO == false then return false end
    GIT_STATUS = set_git_status()
    return true
end

local function force_refresh_git()
    IS_GIT_REPO = is_git_repo()
    refresh_git()
end

local function is_folder_dirty(relpath)
    for _, status in pairs(GIT_STATUS) do
        if string.match(status, relpath) ~= nil then return true end
    end
end

local function create_git_checker(pattern)
    return function(relpath)
        for _, status in pairs(GIT_STATUS) do
            -- TODO: fix .* as it could be problematic
            local ret = string.match(status, '^.. .*' .. relpath)
            if ret ~= nil and string.match(ret, pattern) ~= nil then return true end
        end
        return false
    end
end

local unstaged = create_git_checker('^ ')
local staged = create_git_checker('^M ')
local staged_new = create_git_checker('^A ')
local staged_mod = create_git_checker('^MM')
local unmerged = create_git_checker('^[U ][U ]')
local renamed = create_git_checker('^R')
local untracked = create_git_checker('^%?%?')

local function get_git_attr(path, is_dir)
    if IS_GIT_REPO == false then return '' end
    if is_dir then
        if is_folder_dirty(path) == true then return '✗ ' end
    else
        if unstaged(path) then return '✗ '
        elseif staged(path) then return '✓ '
        elseif staged_new(path) then return '✓★ '
        elseif staged_mod(path) then return '✓✗ '
        elseif unmerged(path) then return '═ '
        elseif renamed(path) then return '➜ '
        elseif untracked(path) then return '★ '
        end
    end

    return ''
end

return {
    get_git_attr = get_git_attr;
    refresh_git = refresh_git;
    force_refresh_git = force_refresh_git;
}