# 📘 `grel-rs` Technical Design Document (v3.0)
**Binary:** `grel` | **Repository:** `grel-rs`  
**Target Platforms:** Linux, Windows (macOS optional)  
**Core Philosophy:** Pure CLI, deterministic asset resolution, pacman/Artix-familiar UX, explicit over implicit, robust upgrade edge-case handling.

---

## 1. Overview & Goals
`grel` (Global/General Release) is a terminal-native, high-performance package manager for downloading and managing binary releases from Git forges. It abstracts provider-specific APIs into a unified resolution pipeline, supports HTTP/SOCKS5 proxies, caches optimal DNS endpoints, downloads assets in parallel, and delivers a transparent, scriptable, pacman-compatible UX.

**Key Requirements Met:**
- ✅ Pure CLI (no TUI/GUI), standard `std::io` prompts
- ✅ Deterministic asset resolution: **filter → sort → explicit prompt** (zero scoring magic)
- ✅ Robust parsing of non-standard release names via `Os`/`Arch` enums + alias mapping
- ✅ Format control: `.deb`/`.rpm`/`.msi`/`.dmg` disabled by default
- ✅ Pacman/Artix-style numbered selection with `[default]`, TTY/CI fallback, `-y`/`--noconfirm`
- ✅ `-Syu` resilience: detects filename renames, handles repo 404s via orphan tracking, explicit migration path
- ✅ Cross-platform PATH integration (`grel path add`), XDG-compliant, no `sudo`
- ✅ Forge-agnostic provider routing (public + self-hosted URLs)

---

## 2. Workspace Architecture
```
grel-rs/
├── Cargo.toml                  # Workspace root (resolver = "2")
├── crates/
│   ├── grel-cli/               # CLI parsing, pure-text prompts, progress routing
│   ├── grel-core/              # Resolution, tokenization, filter/sort pipeline, upgrade state
│   ├── grel-providers/         # Forge trait, registry, API implementations (modules)
│   ├── grel-network/           # HTTP client, proxy routing, IP cache resolver, parallel downloader
│   ├── grel-cache/             # SQLite state, IP cache, artifact storage, TTL eviction
│   └── grel-config/            # Layered config, migrations, asset priority matrices
├── tests/                      # Integration, mock servers, e2e fixtures
└── scripts/                    # CI, release, benchmark helpers
```

| Crate | Responsibility |
|-------|----------------|
| `grel-cli` | Subcommand routing, pure CLI prompt loops, `indicatif` progress, `tabled` output |
| `grel-core` | `PackageRef` parsing, `AssetTokens` extraction, deterministic filter/sort, upgrade planning |
| `grel-providers` | `ReleaseProvider` trait, GitHub/GitLab/Gitea/Codeberg modules, self-hosted auto-detection |
| `grel-network` | Proxy chaining, DNS/IP cache resolver, `JoinSet` parallel downloads, streaming extraction |
| `grel-cache` | `state.sqlite` management, ETag/IP cache, LRU artifact eviction, atomic install temp dirs |
| `grel-config` | TOML loading, env/CLI overrides, schema validation, config migrations |

---

## 3. CLI Specification & Pure UX
No TUI frameworks. All interaction uses standard terminal I/O with predictable, pipe-safe behavior.

### Commands & Aliases
| Command | Aliases | Description |
|---------|---------|-------------|
| `grel sync foo/bar` | `S`, `-S` | Download & install latest |
| `grel sync foo/bar@1.2.3` | `-S` | Pin version |
| `grel search keyword` | `Ss`, `-Ss` | Search across registered forges |
| `grel upgrade` | `Syu`, `-Syu` | Refresh + upgrade installed |
| `grel info foo/bar` | `Si`, `-Si` | Show release metadata |
| `grel list` | `Q`, `-Q` | List installed packages (shows status) |
| `grel remove foo/bar` | `R`, `-R` | Uninstall & clean DB |
| `grel clean` | `Sc`, `-Sc` | Purge artifact/metadata cache |
| `grel path add` | - | Generate shell/registry snippets for `$PATH` |
| `grel migrate old/path new/path` | - | Remap repo path in state DB |

### Pure CLI Prompt (Artix/Pacman Compatible)
```
:: 3 compatible asset(s) found for linux/x86_64
  1) foo-1.0.0-linux-x86_64.tar.gz | 12.4 MB | tar.gz (default)
  2) foo-1.0.0-linux-x86_64-musl.tar.gz | 10.2 MB | tar.gz
  3) foo-1.0.0-linux-amd64.tar.gz | 11.8 MB | tar.gz
:: Select asset to download [1]: _
```
- Accepts `1`–`3` or `Enter` (selects `[1]`)
- Invalid input → `:: Invalid selection. Enter a number [1-3]: `
- `--noconfirm` / `-y` → skips prompt, selects `[1]`
- **Non-Interactive Fallback:** `!std::io::stdin().is_terminal()` → auto-selects `[1]`, prints `ℹ️ Non-interactive mode. Using: <filename>` to `stderr`, never blocks CI/pipes.

---

## 4. Asset Resolution Pipeline (Deterministic)
**No scoring. No fuzzy logic.** Strict filtering → transparent sorting → explicit selection.

### Step 1: Tokenization
Filenames are split on non-alphanumeric characters. Tokens are matched against case-insensitive alias maps for `Os` and `Arch`.
```rust
// foo-v1.2.3-win64-setup.exe → Os::Windows, Arch::X86_64
// bar_1.0.0_linux_amd64.tar.gz → Os::Linux, Arch::X86_64
// app.Darwin.arm64.zip → Os::MacOS, Arch::Aarch64
```
Unknown tokens fall back to `Os::Unknown("...")` or `Arch::Unknown("...")` → never crash, just filter out later.

### Step 2: Strict Filtering
Assets are filtered in fixed order. Failure at any step → discard.
```rust
1. OS matches target OR is Unknown
2. Arch matches priority list OR fallback allowed (32-bit on 64-bit)
3. Format NOT in `ignore_formats` (deb/rpm/msi/dmg disabled by default)
```

### Step 3: Deterministic Sorting
Remaining assets sorted by explicit cascade:
1. `arch_priority` index (lower = better)
2. `prefer_formats` index
3. Lexicographic filename
4. Size descending (tie-breaker)

### Step 4: Selection
- `0` assets → `❌ No compatible assets. Run grel sync --list-assets`
- `1` asset → Auto-select, log `ℹ️ Selected: <filename>`
- `>1` assets → Pure CLI numbered prompt (see §3)

---

## 5. Platform Enums & Alias Mapping
Strongly-typed, exhaustive, infallible parsing.
```rust
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[non_exhaustive]
pub enum Os { Linux, Windows, MacOS, FreeBSD, Android, iOS, Unknown(String) }

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[non_exhaustive]
pub enum Arch { X86_64, Aarch64, I686, ArmV7, ArmV6, Riscv64, S390x, PowerPC64, Unknown(String) }
```
- `FromStr` implemented with `to_lowercase()` + alias table
- `serde` ready for TOML config
- `Display` outputs canonical names for DB/CLI consistency

---

## 6. Configuration vs State Management
**Strict separation.** Humans edit TOML. Machines manage SQLite.

### `~/.config/grel/config.toml`
```toml
[general]
version = 1
max_concurrent = 4
proxy = "http://127.0.0.1:7890"

[assets]
ignore_formats = ["*.deb", "*.rpm", "*.msi", "*.dmg", "*.pkg", "*.AppImage"]
prefer_formats = ["*.tar.gz", "*.tar.xz", "*.zip", "*.exe"]
arch_priority = ["x86_64", "aarch64", "x86", "armv7"]
fallback_to_32bit = true
prefer_musl = false

[migrations]
"legacy/old-tool" = "new-org/old-tool"

[upgrade]
check_interval_hours = 6
max_parallel_checks = 10
```

### `state.sqlite` Schema (`installed` table)
```sql
CREATE TABLE installed (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    forge TEXT NOT NULL,              -- 'github', 'gitlab', or self-hosted base URL
    owner TEXT NOT NULL,
    repo TEXT NOT NULL,
    version TEXT NOT NULL,            -- Strict semver
    asset_filename TEXT NOT NULL,     -- Exact remote filename used
    checksum TEXT,
    install_path TEXT NOT NULL,
    status TEXT NOT NULL DEFAULT 'active' CHECK (status IN ('active', 'orphaned', 'migrated')),
    orphaned_at INTEGER,              -- Unix timestamp when marked unreachable
    last_checked INTEGER,             -- For smart polling intervals
    installed_at INTEGER DEFAULT (strftime('%s', 'now'))
);
CREATE UNIQUE INDEX idx_pkg_unique ON installed(forge, owner, repo);
CREATE INDEX idx_status ON installed(status);
```

---

## 7. `-Syu` Upgrade Logic & Edge Cases
### 7.1 Filename Change Detection
Authors often rename assets (`x86_64` → `amd64`, `.tar.gz` → `.tar.xz`).
1. Load stored `asset_filename` from DB
2. Resolve new release → filter → sort → get `new_best`
3. If `new_best.filename != stored.filename`:
   ```
   ⚠️ Remote asset renamed: old-name.tar.gz → new-name.tar.xz
   ℹ️ Proceeding with update...
   ```
4. Download → verify → extract → **update DB record** with new filename. Proceeds safely.

### 7.2 Repository Rename / 404 Handling
1. Provider fetch → `404` or unreachable
2. Mark `status = 'orphaned'`, set `orphaned_at = now()`
3. Skip in future `-Syu` runs
4. Warn user:
   ```
   ⚠️ Package unreachable: foo/bar (HTTP 404)
   ℹ️ Skipped. Run `grel migrate foo/bar new/path` or `grel remove foo/bar`
   ```
5. **No auto-migration.** Explicit user action required.

### 7.3 Orphaned Visibility
```bash
$ grel list
:: Installed packages (3 active, 1 orphaned)
  🟢 bar/fuzz          1.2.3  linux/x86_64  tar.gz
  🟢 foo/tool          0.9.1  windows/amd64 exe
  🟡 legacy/old-proj   2.0.0  linux/x86_64  tar.gz  [orphaned since 2024-05-01]
```

---

## 8. Networking, Proxy & DNS/IP Caching
- **Proxy Priority:** `--proxy` > `GREL_PROXY` env > `http_proxy`/`all_proxy` > `config.toml`
- **DNS/IP Cache:** 
  1. Resolve `A/AAAA` via `hickory-resolver`
  2. Parallel `TcpStream::connect` probes on `443`
  3. Store fastest IP + RTT in SQLite with `300s` TTL
  4. `reqwest::ClientBuilder::resolve(host, ip)` forces routing
- **Background Refresh:** Idle task pre-warms hot domains, evicts stale entries

---

## 9. Rate Limiting & ETag Optimization
GitHub: 60/hr unauth, 5000/hr auth. `grel` handles gracefully:
1. **ETag Caching:** `If-None-Match` → `304 Not Modified` **free**. Cached in DB.
2. **Smart Polling:** Only checks packages where `last_checked < now() - check_interval_hours`
3. **Rate Limit Parsing:** Reads `X-RateLimit-Remaining`/`Reset`. If `< 50` → sleep/queue.
4. **Auth Prompt:** First run suggests `GREL_GITHUB_TOKEN` for 5000/hr.
5. **`--no-api` Fallback:** Skips remote checks, uses local timestamps only.

---

## 10. PATH Integration & Post-Install
- Installs to `~/.local/share/grel/bin/` (Linux) / `%LOCALAPPDATA%\grel\bin\` (Windows)
- `grel path add` prints exact shell/registry snippets:
  ```bash
  export PATH="$HOME/.local/share/grel/bin:$PATH"
  ```
  ```powershell
  [Environment]::SetEnvironmentVariable("Path", "$env:LOCALAPPDATA\grel\bin;$env:Path", "User")
  ```
- First run: `💡 Run: grel path add to enable global command access`
- XDG-compliant, no `sudo`, no system conflicts.

---

## 11. Security & Reliability
- ✅ TLS: `rustls` only (no native OpenSSL)
- ✅ Checksums: `sha256` verification before extraction
- ✅ Archive safety: Reject `..`, absolute paths, external symlinks
- ✅ Atomic installs: Temp dir → verify → `rename` → DB update
- ✅ No auto-exec: Binaries installed but not run unless invoked
- ✅ Graceful degradation: Network errors → retry/backoff, rate limits → sleep/queue, missing assets → clear error + suggestions

---

## 12. Dependency Matrix
```toml
# Core & Async
tokio = { version = "1", features = ["full"] }
futures = "0.3"
async-trait = "0.1"

# CLI & UX (Pure CLI, no TUI)
clap = { version = "4", features = ["derive", "wrap_help", "string"] }
indicatif = { version = "0.17", features = ["tokio"] }
tracing-indicatif = "0.3"
tabled = "0.16"
owo-colors = "4"

# Network & Proxy
reqwest = { version = "0.12", features = ["rustls-tls", "json", "socks", "stream"] }
hickory-resolver = "0.24"
dashmap = "6"

# Cache & Storage
sqlx = { version = "0.8", features = ["runtime-tokio-rustls", "sqlite"] }
sha2 = "0.10"
directories = "5"
tar = "0.4"
zip = "2"
zstd = "0.13"
xz2 = "0.1"
bzip2 = "0.5"
sanitize-filename = "0.5"

# Config & Utils
figment = { version = "0.10", features = ["toml", "env"] }
semver = "1"
url = "2"
chrono = { version = "0.4", features = ["serde"] }
regex = "1"
serde = { version = "1", features = ["derive"] }
anyhow = "1"
thiserror = "2"
tracing = "0.1"
tracing-subscriber = { version = "0.3", features = ["env-filter", "fmt"] }
```

---

## 13. Testing & CI Strategy
- **Unit:** Token extraction from 20+ messy filenames, filter/sort determinism, config parsing, migration logic
- **Mocked Providers:** `wiremock` for 200/304/403/429/500, rate limit header injection
- **Integration:** Download fixtures → extract → verify checksums & paths, `grel migrate` DB state changes
- **Non-Interactive:** `echo "" | grel sync foo/bar` must not hang, must log to stderr
- **Cross-Platform CI:** `ubuntu-latest`, `windows-latest` (GitHub Actions)
- **Performance:** `criterion` for DNS/IP cache + parallel download throughput
- **Fuzzing:** `cargo-fuzz` on `AssetTokens::from_filename()` + archive path validation

---