local utils = require("utils")
local fw = require("fastweb")
local config = require("fwutils.config")
local request = require("fastweb.request")
local response = require("fastweb.response")
local cjson = require("cjson")
-- 允许的扩展名
local allowed_extensions = {
    "shtml",
    "html",
    "js"
}
local template_engine_bc_this_role = nil
local cfg = nil

local M = {}

function file_get_contents(filepath)
    
    local file, errmsg = io.open(fw.website_dir()..filepath, "r")
    if not file then
        err.server(errmsg)
    end
    local content = file:read("*a")
    if content == nil or content == "" then
        print("file_get_contents error: ",filepath)
        return ""
    end
    local replaced,c2 = M.replace(content)
    if replaced then
        return c2
    end
    return content
end
function menu_top()
    -- 当前请求路径
    local request_path = request.filepath() or ""
    -- 取配置
    local menuData = require("fwutils.menu").get(string.format("%d",cfg.role_id()))
    if not menuData then
        return "<!-- no menu config -->"
    end

    -- 提取并排序主菜单
    local menuItems = {}
    for name, item in pairs(menuData) do
        table.insert(menuItems, {
            name = name,
            item = item,
            sort = item.sort or 0
        })
    end
    table.sort(menuItems, function(a, b)
        return a.sort > b.sort
    end)

    local html = [[

  <ul class="navbar-nav me-auto mb-2 mb-lg-0">
  ]]

    -- 渲染主菜单
    for _, entry in ipairs(menuItems) do
        local name = entry.name
        local item = entry.item
        local icon = item.icon or ""
        local path = item.path or "#"
        local activeClass = ""

        if item.children then
            -- 有子菜单
            local isMegamenu = item.megamenu and " dropdown-megamenu" or ""

            -- 检查子菜单是否有激活
            local hasActiveChild = false
            local children = {}
            for childName, childItem in pairs(item.children) do
                table.insert(children, {
                    name = childName,
                    item = childItem,
                    sort = childItem.sort or 0
                })
                if not hasActiveChild and (request_path == (childItem.path or "")) then
                    hasActiveChild = true
                end
            end
            table.sort(children, function(a, b)
                return a.sort > b.sort
            end)

            -- 父菜单激活：当前页面是父菜单path，或是任一子菜单path
            if request_path == path or hasActiveChild then
                activeClass = "active-link"
            end

            html = html .. [[
    <li class="nav-item dropdown ]] .. activeClass .. [[">
      <a class="nav-link dropdown-toggle" href="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
        <i class="]] .. icon .. [["></i> ]] .. name .. [[
      </a>
      <ul class="dropdown-menu]] .. isMegamenu .. [[">
  ]]

            -- 渲染子菜单
            for _, child in ipairs(children) do
                local childName = child.name
                local childItem = child.item
                local childPath = childItem.path or "#"

                -- 子菜单不设置激活样式
                html = html .. [[
        <li>
          <a class="dropdown-item" href="]] .. childPath .. [[">
            <span>]] .. childName .. [[</span>
          </a>
        </li>
  ]]
            end

            html = html .. [[
      </ul>
    </li>
  ]]
        else
            -- 没有子菜单
            -- 简单的“当前页面是否激活”检查
            if request_path == path then
                activeClass = "active-link"
            end
            html = html .. [[
    <li class="nav-item ]] .. activeClass .. [[">
      <a class="nav-link" href="]] .. path .. [[">
        <i class="]] .. icon .. [["></i> ]] .. name .. [[
      </a>
    </li>
  ]]
        end
    end

    html = html .. [[
  </ul>
  ]]

    return [=[
    <nav class="navbar navbar-expand-lg">
          <div class="container">
            <div class="offcanvas offcanvas-end" id="MobileMenu">
              <div class="offcanvas-header">
                <h5 class="offcanvas-title semibold">Navigation</h5>
                <button type="button" class="btn btn-danger btn-sm ms-auto" data-bs-dismiss="offcanvas">
                  <i class="icon-clear"></i>
                </button>
              </div>
    ]=]..html..[[
            </div>
          </div>
        </nav>
    ]]
end
function template(filepath)
    local path = "/public/user/template/"..config.agent[user_agent_id()].template.."/"..filepath
    return file_get_contents(path) 
end

function teacher_photos()
    require("app.app")
    local agent_id = user_agent_id()
    local teacher = require("app.function.teacher")
    local teacher_info = teacher.get_by_id(pint("id"))
    if teacher_info == nil then
        return ""
    end
    local photos = cjson.decode(teacher_info.photo)
    local content = "<div><div class='home-img'><img src='".. teacher_info.avatar.."' class='img-fluid bg-img' alt=''></div></div>"
    for i,v in ipairs(photos) do
        if type(v) == "string" then
            content = content..[[<div>
                <div class="home-img">
                    <img src="]]..v..[[" class="img-fluid bg-img" alt="">
                </div>
            </div>
            ]] 
        end
    end
    return content
end
-- 更新
M.update = function(conn)
    -- 查询权限表
    local select = conn:select()
    select:table("fw_template")
    select:where_i32("enable","=",1)
    local result = select:query()
    local bc = {
        public = {}
    }
    while result:next() do
        local id = result:get("id")
        local role_id = string.format("%d",result:get("role_id"))
        local key = result:get("key")
        local value = result:get("value")


        if bc[role_id] == nil then
            bc[role_id] = {}
        end
        if role_id == "0" then
            bc["public"][key] = value
        else
            bc[role_id][key] = value
        end
    end
    local code = "return " .. require("serpent").serialize(bc, {comment = false})
    utils.save_file(fw.website_dir().."/"..(config.path.luabytecode:gsub("%.", "/")).."/template_engine_bc.lua",code)
    return true
end
-- 处理
-- @param static_content 静态内容
-- @param cfg 配置
-- @return 是否替换(TRUE则不需要继续处理，FALSE则继续处理)
M.handle = function(__cfg)

    local function has_ext(ext)
        for _, v in ipairs(allowed_extensions) do
            if v == ext then
                return true
            end
        end
        return false
    end


    cfg = __cfg
    template_engine_bc_this_role = {
        template = {
            private = {},
            public = {}
        },
    }


    local ext = utils.ext(cfg.filepath())
    local static_content = nil
    if ext ~= nil  then
        if not has_ext(ext) then
            return false
        end
        -- 读取资源文件
        static_content = utils.read_file(fw.website_dir()..cfg.filepath())
        if static_content == nil or static_content == "" then
            return false
        end
    else
        -- 无需替换的扩展名
        return false
    end 
    local template_engine_bc = require(config.path.luabytecode..".template_engine_bc")
    template_engine_bc_this_role["template"]["private"] = template_engine_bc[string.format("%d",cfg.role_id())]
    template_engine_bc_this_role["template"]["public"] = template_engine_bc["public"]
    

    local replaced,content = M.replace(static_content)
    if replaced then
        static_content = content
    end
    -- 执行函数
    static_content, n = static_content:gsub("%${<<<%s*(.-)%s*>>>}", function(code)
        -- 尝试编译代码（Lua 5.2+ 使用 load；Lua 5.1 可用 loadstring）
        local chunk, errmsg = load(code)
        if not chunk then
            fw.throw_string(errmsg)
        end
        -- 使用 pcall 安全执行代码块
        local status, result = pcall(chunk)
        if not status then 
            fw.throw_string(result)
        end
        -- 如果代码没有返回值，则替换为空字符串，否则转换成字符串返回
        return tostring(result)
    end)

    if n > 0 then
        replaced = true
    end
 
    if replaced then
        if  ext == "shtml" or ext == "html" then
            response.header("Content-Type","text/html")
        elseif ext == "js" then
            response.header("Content-Type","application/javascript")
        end
        response.send(static_content)
        return true
    end
    return false
end
M.replace = function (content)
    if content == nil or content == "" then
        return false 
    end
    -- 支持多级kvs替换，如 ${people.age}
    local function flatten_kvs(tbl, prefix, out)
        if tbl == nil then
            return {}
        end
        out = out or {}
        prefix = prefix or ""
        for k, v in pairs(tbl) do
            local key = prefix ~= "" and (prefix .. "." .. k) or k
            if type(v) == "table" then
                flatten_kvs(v, key, out)
            else
                out[key] = v
            end
        end
        return out
    end

    -- 先提取 content 中所有需要替换的占位符
    -- 需要正确处理 ${<<<...>>>} 块：块内部的 ${...} 需要替换，但块本身不替换
    local placeholders = {}
    
    -- 第一步：提取所有 ${<<<...>>>} 块，临时替换它们，并收集所有占位符
    local blocks = {}
    local block_index = 0
    local temp_content = content:gsub("%${<<<%s*(.-)%s*>>>}", function(block_content)
        block_index = block_index + 1
        local placeholder = "${__TEMP_BLOCK_" .. block_index .. "__}"
        -- 收集块内部的 ${...} 占位符
        for ph in string.gmatch(block_content, "%${([^}]+)}") do
            placeholders[ph] = true
        end
        blocks[block_index] = {
            placeholder = placeholder,
            content = block_content
        }
        return placeholder
    end)
    
    -- 第二步：提取外部（不在 ${<<<...>>>} 块中）的 ${...} 占位符
    for placeholder in string.gmatch(temp_content, "%${([^}]+)}") do
        -- 忽略临时占位符
        if not placeholder:match("^__TEMP_BLOCK_%d+__$") then
            placeholders[placeholder] = true
        end
    end

    -- print("PLACEHOLDERS:",cjson.encode(placeholders))
    
    -- 如果没有任何占位符，直接返回
    if next(placeholders) == nil then
        return false
    end

    -- 合并所有数据源到一个查找表中（只 flatten 一次）
    local value_map = {}
    
    -- PUBLIC
    local flat_kvs = flatten_kvs(template_engine_bc_this_role["template"]["public"])
    for k, v in pairs(flat_kvs) do
        value_map[k] = v
    end
    -- PRIVATE
    flat_kvs = flatten_kvs(template_engine_bc_this_role["template"]["private"])
    for k, v in pairs(flat_kvs) do
        value_map[k] = v
    end
    -- REQUEST
    flat_kvs = flatten_kvs(request.gets(), "request")
    for k, v in pairs(flat_kvs) do
        value_map[k] = v
    end
    -- TOKEN
    flat_kvs = flatten_kvs(cfg.user_data(), "token")
    for k, v in pairs(flat_kvs) do
        value_map[k] = v
    end

    -- 转义函数：将 Lua 模式特殊字符转义为字面匹配
    local function escape_pattern(str)
        return str:gsub("([%^%$%(%)%%%.%[%]%*%+%-%?])", "%%%1")
    end
    
    -- 第三步：先处理 ${<<<...>>>} 块内部的占位符
    local replaced = false
    for i, block in ipairs(blocks) do
        local block_content = block.content
        for placeholder, _ in pairs(placeholders) do
            if value_map[placeholder] ~= nil then
                local escaped_placeholder = escape_pattern(placeholder)
                local new_content, count = string.gsub(block_content, "%${" .. escaped_placeholder .. "}", tostring(value_map[placeholder]))
                if count > 0 then
                    block_content = new_content
                    replaced = true
                end
            end
        end
        blocks[i].processed_content = block_content
    end
    
    -- 第四步：替换外部的 ${...} 占位符（在临时内容中，此时块已被替换为临时占位符）
    local n = 0
    for placeholder, _ in pairs(placeholders) do
        if value_map[placeholder] ~= nil then
            local escaped_placeholder = escape_pattern(placeholder)
            temp_content, n = string.gsub(temp_content, "%${" .. escaped_placeholder .. "}", tostring(value_map[placeholder]))
            if n > 0 then
                replaced = true
            end
        end
    end
    
    -- 第五步：恢复 ${<<<...>>>} 块（使用处理后的内容）
    for i, block in ipairs(blocks) do
        local processed_block = "${<<<" .. blocks[i].processed_content .. ">>>}"
        temp_content = temp_content:gsub(block.placeholder:gsub("([%^%$%(%)%%%.%[%]%*%+%-%?])", "%%%1"), processed_block)
    end
    content = temp_content

    if replaced then
        return true, content
    end
    return false
end

-- 检查内容中是否有TOKEN变量
-- @return boolean
M.hasToken = function()
    if M.static_content == nil or M.static_content == "" then
        return false
    end
    return M.static_content:match("%${token%.") ~= nil
end

return M