---
id: TASK-004
title: Config & persistence layer
status: "\U0001F3C1 Done"
assignee:
  - '@humdrum-tiv'
created_date: '2026-06-16 18:03'
updated_date: '2026-06-18 01:17'
labels:
  - feature
dependencies: []
priority: high
ordinal: 4000
---

## Description

<!-- SECTION:DESCRIPTION:BEGIN -->
XDG config dir (~/.config/pts/). Persists selected leagues, favorite teams, and active theme. Prereq for league-selection, favorites, and theme-switch tasks.
<!-- SECTION:DESCRIPTION:END -->

## Acceptance Criteria
<!-- AC:BEGIN -->
- [x] #1 config read/written under XDG config dir
- [x] #2 missing/corrupt config falls back to defaults
<!-- AC:END -->

## Implementation Plan

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1. New package internal/config:
   - Config{Favorites []FavTeam json:favorites; Leagues []string json:leagues,omitempty; Theme string json:theme,omitempty}
   - FavTeam{League, ID, Abbr, Name string}
   - dir(): XDG_CONFIG_HOME or ~/.config, then /pts ; path(): dir/config.json
   - Load() (Config,error): missing file -> zero Config + nil; corrupt JSON -> zero Config + nil (defaults, swallow) [AC#2]
   - Save(Config) error: mkdir -p dir, marshal indent, atomic write (tmp+rename) [AC#1]
2. Tests (config_test.go, offline, XDG_CONFIG_HOME=t.TempDir): missing->defaults; round-trip Save/Load; corrupt->defaults.
<!-- SECTION:PLAN:END -->

## Final Summary

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Added internal/config: XDG-based persistence for user prefs.

- Config{Favorites, Leagues, Theme} stored as JSON at $XDG_CONFIG_HOME/pts/config.json (falls back to ~/.config/pts/) [AC#1].
- Load() is forgiving: missing or corrupt file returns the zero Config (defaults), never an error, so the app always starts [AC#2].
- Save() writes atomically (temp file + rename), creating the dir as needed.
- Leagues/Theme fields reserved for TASK-002/TASK-005; only Favorites wired so far (TASK-003).

Tests: config_test.go (offline, XDG_CONFIG_HOME=t.TempDir) covers missing->defaults, Save/Load round-trip, corrupt->defaults.
<!-- SECTION:FINAL_SUMMARY:END -->