local addon_name = ...

local MAX_DUMPS = 20
local MAX_DEPTH = 24

local function print_msg(msg)
    print("|cff6fa8dcdev_dump:|r " .. msg)
end

--- Converts a value into something SavedVariables can store.
---
--- SavedVariables only persist strings, numbers, booleans, and tables of
--- those, so anything else is replaced with a descriptive placeholder string.
local function sanitize(value, depth, seen)
    local value_type = type(value)

    if value_type == "string" or value_type == "number" or value_type == "boolean" or value_type == "nil" then
        return value
    end

    if value_type ~= "table" then
        return "<" .. value_type .. ">"
    end

    -- Widgets (frames, textures, and so on) are tables backed by userdata. Dumping
    -- them recursively would pull in half the UI, so summarize them instead.
    if type(value.GetObjectType) == "function" and type(rawget(value, 0)) == "userdata" then
        local ok, object_type = pcall(value.GetObjectType, value)
        local ok_name, name = pcall(value.GetName, value)
        return string.format(
            "<%s %s>",
            ok and object_type or "widget",
            (ok_name and name) or "anonymous"
        )
    end

    if seen[value] then
        return "<cycle>"
    end

    if depth >= MAX_DEPTH then
        return "<max depth>"
    end

    seen[value] = true

    local result = {}
    for key, inner in pairs(value) do
        local key_type = type(key)
        if key_type ~= "string" and key_type ~= "number" and key_type ~= "boolean" then
            key = "<" .. key_type .. " key> " .. tostring(key)
        end
        result[key] = sanitize(inner, depth + 1, seen)
    end

    seen[value] = nil

    return result
end

local function pack(...)
    return { n = select("#", ...), ... }
end

local function dump(expr)
    local entry = {
        expr = expr,
        time = date("%Y-%m-%d %H:%M:%S"),
        build = { GetBuildInfo() },
    }

    local chunk, compile_error = loadstring("return " .. expr, "=devdump")
    if not chunk then
        -- Not an expression, so try it as a statement instead (e.g. `x = 1`).
        chunk, compile_error = loadstring(expr, "=devdump")
    end

    if not chunk then
        entry.error = compile_error
    else
        local results = pack(pcall(chunk))
        if results[1] then
            entry.results = {}
            entry.result_count = results.n - 1
            for i = 2, results.n do
                entry.results[i - 1] = sanitize(results[i], 0, {})
            end
        else
            entry.error = results[2]
        end
    end

    local dumps = dev_dump_db.dumps
    table.insert(dumps, entry)
    while #dumps > MAX_DUMPS do
        table.remove(dumps, 1)
    end

    if entry.error then
        print_msg("|cffff6b5eerror:|r " .. tostring(entry.error))
    else
        print_msg(string.format(
            "saved %d value(s) as dump #%d. /reload to write it to disk.",
            entry.result_count,
            #dumps
        ))
    end
end

local frame = CreateFrame("Frame")
frame:RegisterEvent("ADDON_LOADED")
frame:SetScript("OnEvent", function(self, event, loaded_addon)
    if loaded_addon ~= addon_name then
        return
    end

    dev_dump_db = dev_dump_db or {}
    dev_dump_db.dumps = dev_dump_db.dumps or {}
    self:UnregisterEvent("ADDON_LOADED")
end)

SLASH_DEV_DUMP1 = "/devdump"
SlashCmdList.DEV_DUMP = function(msg)
    msg = strtrim(msg or "")

    if msg == "" then
        print_msg("usage: /devdump <lua expression> | /devdump list | /devdump clear")
    elseif msg == "clear" then
        wipe(dev_dump_db.dumps)
        print_msg("cleared all dumps.")
    elseif msg == "list" then
        if #dev_dump_db.dumps == 0 then
            print_msg("no dumps saved.")
        end
        for i, entry in ipairs(dev_dump_db.dumps) do
            print_msg(string.format("#%d [%s] %s%s", i, entry.time, entry.expr, entry.error and " (error)" or ""))
        end
    else
        dump(msg)
    end
end