local M = {}

local unpack, tostring = unpack, tostring
local concat, insert, remove = table.concat, table.insert, table.remove
local sub, rep, len = string.sub, string.rep, string.len
local COLOR_SYM_DEFAULT, COLOR_STRING_DEFAULT, COLOR_LITERAL_DEFAULT, COLOR_QUOTE_DEFAULT = {221, 221, 221}, {180, 230, 30}, {96, 160, 220}, {218, 230, 30}

function M.format(json_text, line_feed, indent, ac)
    json_text = tostring(json_text)
    line_feed, indent, ac = tostring(line_feed or "\n"), tostring(indent or "\t"), tostring(ac or " ")

    local i, j, k, n, r, p, q = 1, 0, 0, len(json_text), {}, nil, nil
    local al = sub(ac, -1) == "\n"

    for x = 1, n do
        local c = sub(json_text, x, x)

        if not q and (c == "{" or c == "[") then
            r[i] = p == ":" and (c .. line_feed) or (rep(indent, j) .. c .. line_feed)
            j = j + 1
        elseif not q and (c == "}" or c == "]") then
            j = j - 1
            if p == "{" or p == "[" then
                i = i - 1
                r[i] = rep(indent, j) .. p .. c
            else
                r[i] = line_feed .. rep(indent, j) .. c
            end
        elseif not q and c == "," then
            r[i] = c .. line_feed
            k = -1
        elseif not q and c == ":" then
            r[i] = c .. ac
            if al then
                i = i + 1
                r[i] = rep(indent, j)
            end
        else
            if c == '"' and p ~= "\\" then
                q = not q and true or nil
            end
            if j ~= k then
                r[i] = rep(indent, j)
                i, k = i + 1, j
            end
            r[i] = c
        end
        p, i = c, i + 1
    end

    return concat(r)
end

local pretty_json = M.format

function M.highlight(json_text, color_sym, color_quote, color_string, color_literal)
    color_sym, color_string, color_literal, color_quote = color_sym or COLOR_SYM_DEFAULT, color_string or COLOR_STRING_DEFAULT, color_literal or COLOR_LITERAL_DEFAULT, color_quote or COLOR_QUOTE_DEFAULT
    json_text = tostring(json_text)

    local result, prev, quote = {}, nil, nil

    local cur_clr, cur_text = color_sym, {}

    for i = 1, len(json_text) do
        local c = sub(json_text, i, i)
        local new_clr

        if not quote and (c == "{" or c == "[") then
            new_clr = color_sym

            insert(cur_text, c)
        elseif not quote and (c == "}" or c == "]") then
            new_clr = color_sym
            if prev == "{" or prev == "[" then
                insert(cur_text, prev)
            else
                insert(cur_text, c)
            end
        elseif not quote and (c == "," or c == ":") then
            new_clr = color_sym
            insert(cur_text, c)
        else
            if c == '"' and prev ~= "\\" then
                quote = not quote and true or nil
                new_clr = color_quote
            elseif cur_clr == color_quote then
                new_clr = quote and color_string or color_literal
            elseif cur_clr == color_sym and (c ~= " " and c ~= "\n" and c ~= "\t") then
                new_clr = quote and color_string or color_literal
            end

            insert(cur_text, c)
        end

        if new_clr ~= nil and new_clr ~= cur_clr then
            local new_text = {remove(cur_text, #cur_text)}

            insert(result, {cur_clr[1], cur_clr[2], cur_clr[3], concat(cur_text)})

            cur_clr, cur_text = new_clr, new_text
        end

        prev = c
    end

    if #cur_text > 0 then
        insert(result, {cur_clr[1], cur_clr[2], cur_clr[3], concat(cur_text)})
    end

    return result
end

local highlight_json = M.highlight

function M.print_highlighted(json_text, color_sym, color_quote, color_string, color_literal)
    local highlighted = highlight_json(json_text, color_sym, color_string, color_literal, color_quote)
    local count = #highlighted

    local t = {}
    for i = 1, count do
        local r, g, b, str = unpack(highlighted[i])
        t[#t + 1] = table.concat({"\a", color(r, g, b):to_hex(), str, i == count and "" or "\0"})
    end
    print_raw(unpack(t))

    return highlighted
end

function M.stringify(tbl, line_feed, indent, ac)
    local success, json_text = pcall(json.stringify, tbl)
    if not success then
        error(json_text, 2)
        return
    end

    return pretty_json(json_text, line_feed, indent, ac)
end

return M