---
phase: 07-custom-rules-and-print-config
plan: "02"
subsystem: config, cmd/netsynth
tags: [config, cli, print-config, rules, wiring, CFG-06, RULE-02]
dependency_graph:
  requires: [LoadResult, UserRules, AutoClasses, PrintConfig]
  provides: [--print-config flag, runPrintConfig, user-rule-prepend, PrintConfig-output]
  affects: [cmd/netsynth/main.go, config/config.go]
tech_stack:
  added: ["sort", "time", "strings.Builder"]
  patterns: [LoadResult-propagation, user-rule-prepend, annotated-TOML-output]
key_files:
  created: []
  modified:
    - cmd/netsynth/main.go
    - cmd/netsynth/main_test.go
    - config/config.go
    - config/config_test.go
decisions:
  - "--print-config check placed after --list-interfaces but before interface-required validation so it works without -i"
  - "AutoClasses map added to LoadResult to track which classes were auto-assigned by FNV-32a"
  - "PrintConfig returns a string (not writes to io.Writer) for testability; caller prints to stdout"
  - "waveformString returns custom for WaveformCustom (zero value used by hand-tuned built-in classes)"
  - "classAnnotation: built-in classes compared on both BaseHz and WaveformType for override detection"
metrics:
  duration: 8min
  completed: "2026-03-26T20:55:00Z"
  tasks_completed: 2
  files_modified: 4
---

# Phase 7 Plan 02: CLI Wiring and PrintConfig Output Summary

Wire the LoadResult into main.go (user rules prepend, --print-config flag), implement the PrintConfig output function in the config package, and add comprehensive tests for both. Completes RULE-02 and CFG-06 — the final plan for Phase 7 and the v1.1 milestone.

## What Was Built

**cmd/netsynth/main.go:**
- Added `printConfig bool` var and `--print-config` flag registration
- `runPrintConfig()`: calls `config.Load(configPath)` then `config.PrintConfig(result)`, prints to stdout, exits clean
- --print-config check fires before interface-required validation (no -i needed)
- `runLiveMode` and `runPcapMode` now accept `config.LoadResult` instead of bare `map[TrafficClass]FreqConfig`
- User rules prepend in both modes: `append(result.UserRules, classify.DefaultRules...)` (RULE-02)
- Removed unused `synth` import

**config/config.go:**
- `LoadResult` gains `AutoClasses map[classify.TrafficClass]bool` field
- `addAutoFreqEntries` updated to accept and populate `autoClasses` map
- `Load()` initializes `AutoClasses` map and returns it in `LoadResult`
- `PrintConfig(result LoadResult) string`: generates commented TOML output with:
  - Header: `# NetSynth effective configuration`, `# Config source: <path or "none (using defaults)">`, `# Generated: <UTC timestamp>`
  - `[[rules]]` section for each user rule (port omitted when DstPort==0)
  - `[sounds.*]` section for all classes in deterministic order (14 built-ins in AllClasses() order, then user-defined sorted alphabetically)
  - Per-class annotation: `(default)`, `(override)`, or `(auto-assigned)`
- `waveformString()`: converts WaveformType to TOML string
- `classAnnotation()`: determines annotation based on AutoClasses membership and comparison with defaults

## Tasks Completed

| Task | Name | Commit | Files |
|------|------|--------|-------|
| 1 | Wire LoadResult into main.go and add --print-config flag | d43914f | cmd/netsynth/main.go, cmd/netsynth/main_test.go |
| 2 | Implement PrintConfig output function with comment annotations | b52e36b | config/config.go, config/config_test.go |

## Deviations from Plan

None - plan executed exactly as written.

## Test Coverage

New tests added (8 PrintConfig tests in config_test.go, 3 print-config tests in main_test.go):

**config/config_test.go:**
- `TestPrintConfigContainsAllClasses` - all 14 class names in output
- `TestPrintConfigSourcePath` - `# Config source: <path>` in header
- `TestPrintConfigNoSourcePath` - `# Config source: none` when no config
- `TestPrintConfigContainsRules` - `[[rules]]` section with port/protocol/class
- `TestPrintConfigRuleNoPort` - port line omitted when DstPort==0
- `TestPrintConfigDefaultAnnotation` - `(default)` for unmodified built-in class
- `TestPrintConfigOverrideAnnotation` - `(override)` for modified built-in class
- `TestPrintConfigAutoAssignedAnnotation` - `(auto-assigned)` for FNV-hash assigned class

**cmd/netsynth/main_test.go:**
- `TestPrintConfigFlagRegistered` - flag exists on command
- `TestPrintConfigNoInterface` - --print-config works without -i
- `TestPrintConfigWithConfigFile` - --print-config with --config succeeds

Full suite: `go test ./... -count=1` all 7 packages pass.

## Known Stubs

None. All functionality is fully implemented and wired.

## Self-Check: PASSED