code_impacted.lua

-- MCP Tool: code_impacted
-- Impact analysis: what files are affected by changing a file/symbol
-- Entry kind: function.lua

local tools = require("tools")
local fmt = require("fmt")

local function call(arguments)
    if not arguments.file or arguments.file == "" then
        return tools.format_error("'file' parameter is required")
    end

    local result, err = tools.request("query:impacted", {
        file = arguments.file,
        depth = arguments.depth or 2,
        project = arguments.project,
    })

    if err then return tools.format_error(err) end

    local lines = {}
    table.insert(lines, "# Impact Analysis: " .. (result.source or arguments.file))
    table.insert(lines, "")

    -- Direct
    local direct_count = 0
    local direct_files = {}
    for file, info in pairs(result.direct or {}) do
        direct_count = direct_count + 1
        table.insert(direct_files, {
            file = file,
            ref_count = #(info.refs or {}),
        })
    end
    table.sort(direct_files, function(a, b) return a.ref_count > b.ref_count end)

    table.insert(lines, string.format("## Directly Impacted — %d files", direct_count))
    for _, df in ipairs(direct_files) do
        table.insert(lines, string.format(
            "  %-50s — %d references", df.file, df.ref_count
        ))
    end
    table.insert(lines, "")

    -- Transitive
    local trans_count = 0
    local trans_files = {}
    for file, info in pairs(result.transitive or {}) do
        trans_count = trans_count + 1
        table.insert(trans_files, {
            file = file,
            via = info.via,
            depth = info.depth,
        })
    end
    table.sort(trans_files, function(a, b) return a.file < b.file end)

    if trans_count > 0 then
        table.insert(lines, string.format(
            "## Transitively Impacted — %d additional files", trans_count
        ))
        for _, tf in ipairs(trans_files) do
            table.insert(lines, string.format(
                "  %-50s — via %s (depth %d)", tf.file, tf.via, tf.depth
            ))
        end
        table.insert(lines, "")
    end

    table.insert(lines, string.format(
        "Total: %d files potentially impacted",
        direct_count + trans_count
    ))

    return table.concat(lines, "\n")
end

return { call = call }