local guide  = require 'parser.guide'
local config = require 'config'

local type         = type
local setmetatable = setmetatable
local ipairs       = ipairs

_ENV = nil

---@class engineer
local mt = {}
mt.__index = mt
mt.type = 'engineer'

--- 获取对象作为域时的名字
function mt:getFieldName(obj)
    if obj.type == 'getglobal' or obj.type == 'setglobal' then
        return obj[1]
    end
    return nil
end

--- 查找所有局部变量引用
function mt:eachRefAsLocal(obj, callback)
    callback(obj, 'local')
    if obj.ref then
        for _, ref in ipairs(obj.ref) do
            local refObj = self.root[ref]
            if refObj.type == 'setlocal' then
                callback(self.root[ref], 'set')
            elseif refObj.type == 'getlocal' then
                callback(self.root[ref], 'get')
            end
        end
    end
end

--- 查找所有全局变量引用
function mt:eachRefAsGlobal(obj, callback)
    local version = config.config.runtime.version
    if version ~= 'Lua 5.1' and version ~= 'LuaJIT' then
        self:eachRefAsField(obj, callback)
        return
    end
end

--- 查找所有域引用
function mt:eachRefAsField(obj, callback)
    local nodeID = obj.node
    if not nodeID then
        return
    end
    local node = self.root[nodeID]
    local key = guide.getKeyName(obj)
    if not key then
        return
    end
    guide.eachField(self.value, node, key, function ()
    end)
end

--- 查找所有引用
function mt:eachRef(obj, callback)
    if obj.type == 'local' then
        self:eachRefAsLocal(obj, callback)
    elseif obj.type == 'getlocal' or obj.type == 'setlocal' then
        local loc = self.root[obj.loc]
        self:eachRefAsLocal(loc, callback)
    elseif obj.type == 'setglobal' or obj.type == 'getglobal' then
        self:eachRefAsGlobal(obj, callback)
    end
end

return function (ast)
    if not ast.vm then
        ast.vm = {}
    end
    local self = setmetatable({
        step  = 0,
        root  = ast.root,
    }, mt)
    return self
end