---@alias itemInspected table<string, any>

local linesPrinted = 0
local termWidth, termHeight = term.getSize()

---@type table<string,fun():boolean,itemInspected|nil>
local inspectSides = {
    up = turtle.inspectUp,
    u = turtle.inspectUp,
    down = turtle.inspectDown,
    dn = turtle.inspectDown,
    d = turtle.inspectDown,
    [""] = turtle.inspect,
    forward = turtle.inspect,
    fd = turtle.inspect,
    f = turtle.inspect,
}

---@param t table<string,any>
local function pairsByKeys(t)
    local allKeys = {}
    for k in pairs(t) do
        if type(k) == "string" then
            table.insert(allKeys, k)
        end
    end
    table.sort(allKeys)
    local i = 0
    return function()
        i = i + 1
        local key = allKeys[i]
        if key == nil then
            return nil
        end
        return key, t[key]
    end
end

---@param t table<string,any>
---@param indent number|nil
local function printPairs(t, indent)
    indent = indent or 0
    for k, v in pairsByKeys(t) do
        if linesPrinted >= termHeight - 2 then
            term.setTextColor(colors.gray)
            write("(Press a key to keep printing)")
            os.pullEvent("key")
            term.clearLine()
            local _, y = term.getCursorPos()
            term.setCursorPos(1, y)
        end

        if indent > 0 then
            term.setTextColor(colors.gray)
            term.write(string.rep("  ", indent - 1))
            term.write("- ")
        end
        term.setTextColor(colors.lightGray)
        linesPrinted = linesPrinted + write(tostring(k) .. ": ")
        if type(v) == "string" then
            term.setTextColor(colors.lime)
            linesPrinted = linesPrinted + print(v)
        elseif type(v) == "boolean" then
            term.setTextColor(colors.purple)
            linesPrinted = linesPrinted + print(v)
        elseif type(v) == "number" then
            term.setTextColor(colors.purple)
            linesPrinted = linesPrinted + print(v)
        elseif type(v) == "table" then
            linesPrinted = linesPrinted + print()
            printPairs(v, indent + 1)
        else
            linesPrinted = linesPrinted + print(v)
        end
    end
end

---@param inspectFunc fun():boolean,itemInspected|nil
local function inspectBlock(inspectFunc)
    local any, item = inspectFunc()
    if not any or not item then
        term.setTextColor(colors.red)
        print("Cannot inspect air")
    else
        printPairs(item)
    end
end

---@param slot number
local function inspectSlot(slot)
    local item = turtle.getItemDetail(slot)
    if item == nil then
        term.setTextColor(colors.red)
        print("Cannot inspect air")
    else
        printPairs(item)
    end
end

local args = { ... }

local function usage(msg)
    msg = msg and (msg .. "\n") or ""
    error(msg .. 'usage: inspect [slot:integer|side:string]', 0)
end

local target = args[1] or ""
local targetSlot = tonumber(target)

if targetSlot then
    if targetSlot > 16 or targetSlot < 1 then
        usage("slot must be in the range of 1-16 (inclusive)")
    end
    inspectSlot(targetSlot)
else
    local inspectFunc = inspectSides[target]

    if inspectFunc then
        inspectBlock(inspectFunc)
    else
        local valid = {}
        for key in pairs(inspectSides) do
            if key ~= "" then
                table.insert(valid, key)
            end
        end
        usage('unknown side: "' .. target .. '"\nvalid sides: ' .. table.concat(valid, ", "))
    end
end