-- Copyright (c) 2018, xiedacon.

local fs = { _VERSION = "0.1" }

local function popen (command, n)
    if not n then n = 3 end
    local result, err

    for i = 1, n do
        local file = io.popen(command)
        result, err = file:read("*a")
        file:close()

        if err and err == "Interrupted system call" then
        else
            break
        end
    end

    return result, err
end

function fs.read (path, n)
    local content, err = fs.readFile(path)

    if not content then
        if err == "Is a directory" then
            return fs.readdir(path, n)
        else
            return nil, err
        end
    else
        return content
    end
end

function fs.readdir (path, n)
    local content = popen("ls -a '" .. path .. "'", n)

    if not content or content == "" then
        return nil, "No such file or directory"
    end

    local dir = {}
    local i = 0
    local start = 1
    while true do
        i = string.find(content, "\n", i + 1)
        if i == nil then 
            break
        else
            local file = string.sub(content, start, i - 1)
            start = i + 1

            if file ~= "." and file ~= ".." then
                table.insert(dir, file)
            end
        end
    end

    return dir
end

function fs.readFile (path)
    local file, err = io.open(path)

    if not file then
        return nil, err
    end

    local content, err = file:read("*a")

    if not content then
        file:close()
        return nil, err
    end

    file:close()
    return content, err
end

function fs.writeFile (path, content)
    local file, err = io.open(path, "w+")

    if not file then
        return false, err
    end

    local ok, err = file:write(content)

    if not ok then
        file:close()
        return false, err
    end

    file:close()
    return true, err
end

fs.write = fs.writeFile

fs.appendToFile = function (path, content)
    local file, err = io.open(path, "a")

    if not file then
        return false, err
    end

    local ok, err = file:write(content)

    if not ok then
        file:close()
        return false, err
    end

    file:close()
    return true, err
end

function fs.exists (path)
    local file, err = io.open(path)

    if not file then
        return false
    else
        return true
    end
end

function fs.copy (path1, path2)
    local content, err = fs.read(path1)

    if not content then
        return false, err
    end

    local ok, err = fs.write(path2, content)

    if not ok then
        return false, err
    end

    return true
end

function fs.move (path1, path2)
    local ok = os.execute("mv '" .. path1 .. "' '" .. path2 .. "'")

    if not ok then
        return false, "failed to move " .. path1 .. " to " .. path2
    else
        return true
    end
end

function fs.mkdir (path)
    local ok = os.execute("mkdir -p '" .. path .. "'")

    if not ok then
        return false, "failed to mkdir " .. path
    else
        return true
    end
end

function fs.rm (path)
    local ok = os.execute("rm '" .. path .. "'")

    if not ok then
        return false, "failed to rm " .. path
    else
        return true
    end
end

fs.remove = fs.rm

function fs.rmdir (path)
    local ok = os.execute("rmdir '" .. path .. "'")

    if not ok then
        return false, "failed to rmdir " .. path
    else
        return true
    end
end

function fs.unlink (path)
    local ok = os.execute("unlink '" .. path .. "'")

    if not ok then
        return false, "failed to unlink " .. path
    else
        return true
    end
end

function fs.rmAll (path)
    local ok = os.execute("rm -rf '" .. path .. "'")

    if not ok then
        return false, "failed to rmAll " .. path
    else
        return true
    end
end

fs.removeAll = fs.rmAll

function fs.chown (path, own)
    local ok = os.execute("chown '" .. own .. "' '" .. path .. "'")

    if not ok then
        return false, "failed to chown " .. own .. " " .. path
    else
        return true
    end
end

function fs.chmod (path, mode)
    local ok = os.execute("chmod '" .. tostring(mode) .. "' '" .. path .. "'")

    if not ok then
        return false, "failed to chmod " .. tostring(mode) .. " " .. path
    else
        return true
    end
end

function fs.isDir (path)
    local file = io.open(path)

    if not file then
        return false
    end

    local content, err = file:read(0)
    file:close()

    if not content and err == "Is a directory" then
        return true
    else
        return false
    end
end

function fs.isFile (path)
    local file = io.open(path)

    if not file then
        return false
    end

    local content = file:read(0)
    file:close()

    if not content then
        return false
    else
        return true
    end
end

return fs