//! `uiparent_probe`: run the reported spot, not a paraphrase of it.
//!
//! ```text
//! cargo run -q -p benilla-ui --example uiparent_probe -- /path/to/UIParent.lua
//! cargo run -q -p benilla-ui --example uiparent_probe -- /path/to/FriendsFrame.lua
//! ```
//!
//! Loads a real TurtleWoW `Interface\FrameXML` file through benilla's VM and calls the function its
//! 1.12-era error was reported in, so the raise is reproduced at the exact line and then cleared:
//!
//! - `UIParent.lua` — `UIFrameFade_CreateInfo`, whose `wipe(frame.fadeInfo)` (line 1420) raised
//!   `attempt to call global 'wipe' (a nil value)`.
//! - `FriendsFrame.lua` — the guild-roster filter's `trim(strlower(...))` (line 490).
//!
//! These files load far past the reported line in a real session, so a clean `OK` means the chunk
//! parsed, its globals landed, and the call itself behaved. Exits 1 on any raise, naming the chunk.
use std::path::Path;

use benilla_ui::script::UiScript;

fn main() {
    let mut args = std::env::args().skip(1);
    let path = args
        .next()
        .unwrap_or_else(|| panic!("usage: uiparent_probe <UIParent.lua|FriendsFrame.lua>..."));
    let bytes = std::fs::read(Path::new(&path)).expect("read the FrameXML file");
    let name = format!("Interface\\FrameXML\\{}", file_name(&path));

    let script = UiScript::new().expect("new UiScript");
    script
        .run_chunk_named(&bytes, &name)
        .unwrap_or_else(|e| fail(&format!("loading {name}"), e));

    // Each file is probed at the function a 1.12-era error was reported in, chosen by its name.
    let call = match file_name(&path).as_str() {
        "UIParent.lua" => {
            r#"
            local f = CreateFrame("Frame")
            local first = UIFrameFade_CreateInfo(f)
            first.mode = "IN"
            first.timeToFade = 0.5
            local second = UIFrameFade_CreateInfo(f)
            -- the wipe branch never reassigns `frame.fadeInfo`, so it returns the SAME table,
            -- emptied: which is what makes `wipe` a same-identity clear, not a replacement
            return first == second and first.mode == nil and first.timeToFade == nil
                and getn(first) == 0
        "#
        }
        "FriendsFrame.lua" => {
            r#"
            -- The reported line 490 sits inside `GuildStatus_Update`, so the probe calls THAT, not a
            -- transcription of the line — the traceback then names FriendsFrame.lua:490 the way the
            -- session did. The handful of globals it touches first are stubbed here; each is a
            -- no-argument answer the real binding supplies, and an empty roster means the filter
            -- loop never runs, which leaves the trim/wipe pair as the reachable work.
            local function stub(n) return function() return n end end
            -- Every widget this file reaches for is created by `FriendsFrame.xml` at load time, not
            -- by its Lua, so a Lua-only chunk starts with none of them. Naming each one would be a
            -- list as long as the file; a `_G` metatable answers them all the way the XML would, and
            -- it is keyed on the name so the API the probe IS testing still raises.
            local FRAME_NAMES = {
                FriendsFrame = true, GuildFrame = true, SearchResult = true,
            }
            local function frame_stub()
                return { Enable = stub(nil), Disable = stub(nil), Show = stub(nil),
                    Hide = stub(nil), SetText = stub(nil), SetTextColor = stub(nil),
                    SetPoint = stub(nil), ClearAllPoints = stub(nil), SetParent = stub(nil),
                    SetHeight = stub(nil), SetWidth = stub(nil), SetScale = stub(nil),
                    ShowChildren = stub(nil), GetText = stub("  Guild Name  "),
                    GetName = stub("ProbeFrame"), GetObjectType = stub("Frame"),
                    GetParent = stub(nil), IsShown = stub(nil), GetNumChildren = stub(0),
                    GetChildren = stub({}), SetAllPoints = stub(nil), SetFocus = stub(nil) }
            end
            local under_test = { wipe = true, trim = true, strsplit = true, strjoin = true }
            -- Answered as frames, but really bare functions in the 1.12 UI: a frame stub would
            -- raise `attempt to call global 'X' (a table value)` on the first one the file reaches.
            -- 1.12's FauxScrollFrame API is bare functions (`FauxScrollFrame_Update`, `..._SetOffset`),
            -- and the family is long enough that listing it is how the probe goes stale. Every one
            -- is matched by prefix; the `Get*` shapes answer 0, which is an empty scrollbar.
            local function is_bare(name)
                return strfind(name, "FauxScrollFrame_") ~= nil
            end
            setmetatable(_G, {
                __index = function(_, name)
                    -- The four names the probe is here to test stay nil, so a missing one still
                    -- raises `attempt to call global '<name>'` at the real line.
                    if under_test[name] then return nil end
                    if is_bare(name) then
                        local gets = strfind(name, "_Get") ~= nil
                        local fn = stub(gets and 0 or nil)
                        rawset(_G, name, fn)
                        return fn
                    end
                    if not (strfind(name, "Frame") or strfind(name, "Button")
                        or strfind(name, "Text") or FRAME_NAMES[name]) then
                        return nil
                    end
                    local f = frame_stub()
                    rawset(_G, name, f)
                    return f
                end,
            })

            -- Bare-API globals the metatable above would otherwise answer with a frame stub, because
            -- their names read like widgets: `GetText("GUILD_TOTAL", ...)` is 1.12's localisation
            -- lookup, not a widget method.
            GetText = stub("%d")
            GUILD_TOTAL = "Guild Total"
            GUILD_TOTALONLINE = "Guild Total Online"
            -- The same trap for the FauxScrollFrame API: `FauxScrollFrame_*` are bare functions in
            -- the 1.12 UI, but the name matches no widget suffix, so they are listed as one.
            PanelTemplates_SetTab = stub(nil)
            ShowUIPanel = stub(nil)
            HideUIPanel = stub(nil)
            GetNumGuildMembers = stub(0)
            GetGuildRosterInfo = stub("")
            GetGuildRosterSelection = stub(0)
            GetGuildRosterMOTD = stub("")
            FRIENDS_LEVEL_TEMPLATE = "%d %s"
            IsGuildLeader = stub(nil)
            CanGuildInvite = stub(nil)
            CanEditMOTD = stub(nil)
            GetGuildInfo = stub(nil)
            GetGuildLeaderInfo = stub(nil)
            UnitName = stub("probe")
            GetClassInfo = stub("Warrior")
            GUILD_MOTD_EDITLABEL = "motd"

            GuildStatus_Update()
            -- the wipe ran on the global roster table, and the trim fed it a clean search string
            return getn(SearchResult) == 0
        "#
        }
        other => panic!("no probe written for {other} — add the function its error named"),
    };
    let ok: bool = script
        .eval(call)
        .unwrap_or_else(|e| fail(&format!("the reported call in {name}"), e));

    if !ok {
        eprintln!(
            "FAILED: the reported call in {name} ran but did not behave as 1.12-era code expects"
        );
        std::process::exit(1);
    }
    println!("OK: {name} loaded and the reported call ran clean");
}

fn file_name(path: &str) -> String {
    path.rsplit(['/', '\\']).next().unwrap_or(path).to_string()
}

fn fail(stage: &str, e: mlua::Error) -> ! {
    eprintln!("FAILED while {stage}: {e}");
    std::process::exit(1);
}