LinqArray

LinqArray = class()

function LinqArray:init(items)
    if items then
        self:addRange(items)
    end
end

function LinqArray:add(item)
    table.insert(self, item)
end

function LinqArray:addRange(items)
    for k,v in ipairs(items) do
        self:add(v)
    end
end

function LinqArray:where(func)
    local results = LinqArray()
    for k, v in ipairs(self) do
        if func(v) then
            results:add(v)
        end
    end

    return results
end

function LinqArray:select(func)
    local results = LinqArray()
    for k, v in ipairs(self) do
        results:add(func(v))
    end

    return results
end

function LinqArray:selectMany(func)
    local results = LinqArray()
    local selectResults = self:select(func)

    for _,item in ipairs(selectResults) do
        results:addRange(item)
    end

    return results
end

function LinqArray:count()
    return # self
end

function LinqArray:first() return self[1] end

function LinqArray:distinct(objHashFunc)
    local results = LinqArray()
    local valueExists = {}

    if objHashFunc then
        for k, v in ipairs(self) do
            if not valueExists[objHashFunc(v)] then
                results:add(v)
                valueExists[objHashFunc(v)] = true
            end
        end
    else
        for k, v in ipairs(self) do
            if not valueExists[v] then
                results:add(v)
                valueExists[v] = true
            end
        end
    end

    return results
end

function LinqArray:toDictionary(keyFunc, valueFunc)
    local results = {}
    for k, v in ipairs(self) do
        results[keyFunc(v)] = valueFunc(v)
    end

    return results
end

function LinqArray:sum(func)
    local sum = 0

    if func then
        for k, v in ipairs(self) do
            sum = sum + func(v)
        end
    else
        for k, v in ipairs(self) do
            sum = sum + v
        end
    end

    return sum
end

function LinqArray:avg(func)
    return self:sum(func) / self:count()
end

function LinqArray:any(func)
    local results = self
    if func then
        results = results:where(func)
    end
    return results:count() > 0
end

function LinqArray:minOrMax(selector, cond)
    local curResult = nil
    local curVal

    for _,i in ipairs(self) do
        if selector then
            curVal = selector(i)
        else
            curVal = i
        end

        if not curResult then
            curResult = curVal
        elseif cond(curVal, curResult) then
            curResult = curVal
        end
    end

    return curResult
end

function LinqArray:min(selector)
    return self:minOrMax(selector, function(a,b) return a < b end)
end

function LinqArray:max(selector)
    return self:minOrMax(selector, function(a,b) return a > b end)
end

function LinqArray:removeWhere(func)
    local i = 1
    while i <= self:count() do
        if func(self[i]) then
            table.remove(self, i)
        else
            i = i + 1
        end
    end
end