linkleaf-core 0.1.1

<h1 align="center">Linkleaf</h1>

<p align="center">
  Manage <strong>protobuf-only</strong> Linkleaf feeds (<code>linkleaf.v1</code>)
</p>

A tiny library for storing, updating, and querying a personal link feed backed by a compact **Protocol Buffers** file. It gives you ergonomic helpers to:

- Add or update links (upsert) and keep them newest-first
- List links with optional tag and date filters
- Read and write feeds from disk (atomic write, best-effort)
- Parse tags from a comma-separated string

It’s built on `prost` (for protobuf).

## Data model

```
// Generated by prost (simplified):
pub struct Link {
    pub id: String,            // UUID v4 (string)
    pub title: String,
    pub url: String,
    pub date: String,          // "YYYY-MM-DD HH:MM:SS" (local time)
    pub summary: String,
    pub tags: Vec<String>,     // normalized via parse_tags
    pub via: String,           // attribution/source
}

pub struct Feed {
    pub version: i32,          // currently initialized to 1 on new feeds
    pub links: Vec<Link>,      // newest-first
    // (other fields like `title` may exist; not required by the helpers)
}
```

### Feed and Link Schemas

Defined in [`feed.proto`](proto/linkleaf/v1/feed.proto):

- Link
  - `id` (string) — auto-derived if omitted
  - `title` (string, required)
  - `url` (string, required)
  - `date` (string, YYYY-MM-DD)
  - `summary` (optional string)
  - `tags` (optional repeated strings)
  - `via` (optional string)

- Feed
  - `title` (string)
  - `version` (uint32)
  - `links` (repeated Link, newest first)

## Examples
```
# run the minimal flow
cargo run --example quickstart

# upsert by id (moves updated link to front)
cargo run --example upsert_by_id

# upsert by URL when id=None
cargo run --example upsert_by_url

# tag & date filtering
cargo run --example filter

```

## Design notes

- Timestamps are stored as local time strings ("YYYY-MM-DD HH:MM:SS"). Filtering compares the date component only.
- Ordering is newest-first (index 0). Inserts and updates are re-inserted at the front.
- Concurrency: writes are not lock-guarded; concurrent writers can race. Add a lock if multiple processes may write at once.

## TODO
- add function -> accepts tags as Vec<String> instead of Option<String>
- add tag next release
- use git-cliff