# Battlesnake Python Starter Project
An official Battlesnake template written in Python. Get started at [play.battlesnake.com](https://play.battlesnake.com).

![Battlesnake Logo](https://media.battlesnake.com/social/StarterSnakeGitHubRepos_Python.png)

This project is a great starting point for anyone wanting to program their first Battlesnake in Python. It can be run locally or easily deployed to a cloud provider of your choosing. See the [Battlesnake API Docs](https://docs.battlesnake.com/api) for more detail.

## Technologies Used
This project uses [Python 3](https://www.python.org/) and [Flask](https://flask.palletsprojects.com/). It also comes with an optional [Dockerfile](https://docs.docker.com/engine/reference/builder/) to help with deployment.

## Run Your Battlesnake
Install dependencies using pip

```sh
pip install -r requirements.txt
```

Start your Battlesnake
```sh
python main.py
```

You should see the following output once it is running

```sh
Running your Battlesnake at http://0.0.0.0:8000
 * Serving Flask app 'My Battlesnake'
 * Debug mode: off
```

Open [localhost:8000](http://localhost:8000) in your browser and you should see

```json
{"apiversion":"1","author":"","color":"#888888","head":"default","tail":"default"}
```

## Play a Game Locally
Install the [Battlesnake CLI](https://github.com/BattlesnakeOfficial/rules/tree/main/cli)
* You can [download compiled binaries here](https://github.com/BattlesnakeOfficial/rules/releases)
* or [install as a go package](https://github.com/BattlesnakeOfficial/rules/tree/main/cli#installation) (requires Go 1.18 or higher)

Command to run a local game
```sh
battlesnake play -W 11 -H 11 --name 'Python Starter Project' --url http://localhost:8000 -g solo --browser
```

## Next Steps
Continue with the [Battlesnake Quickstart Guide](https://docs.battlesnake.com/quickstart) to customize and improve your Battlesnake's behavior.

## Included Competitive Snake
This repo now includes `snakes/BestBattleSnake.py`, a stronger default snake that combines:
- collision and head-to-head risk checks
- flood-fill space evaluation to avoid traps
- food routing that gets more aggressive as health drops
- tail access checks for better long-term survival

Run it explicitly with:
```sh
SNAKE=BestBattleSnake python main.py
```

Optional duel tuning (when only 2 snakes are alive):
```sh
BATTLE_SNAKE_DUEL_STYLE=balanced python main.py
```

Allowed values: `safe`, `balanced`, `aggressive`.

## PrismBattleSnake_GPT_5_6_Sol
`PrismBattleSnake_GPT_5_6_Sol` is a separate snake that keeps Apex's strategy while
accelerating hot spatial operations with a Python-integer bitboard engine. It
also shares duel transpositions across candidate moves, uses principal-variation
ordering and aspiration windows, and runs a compact adversarial multiplayer
rollout with simultaneous enemy responses. Its filename, class, and registry
key include the model name, while its public Battlesnake API name remains
`PrismBattleSnake`.

Run it with:
```sh
SNAKE=PrismBattleSnake_GPT_5_6_Sol python main.py
```

Benchmark Apex and Prism against sampled positions from a gameplay database:
```sh
python scripts/benchmark_snakes_from_db.py \
  --database /path/to/gameplay.sqlite3 \
  --samples 100
```

The benchmark opens SQLite read-only and reports mean, median, p95, and maximum
move latency. Increase `--samples` for a broader but slower comparison.

Run the deterministic CI-friendly arena benchmark without a gameplay database:
```sh
just bench-snake-arena positions=100
```

It reports latency, reached minimax depth, and move disagreements between Apex
and Prism. Add `output=data/arena-report.json` to save a machine-readable report.
For representative strategy evaluation, provide recorded positions to
`scripts/benchmark_snake_arena.py --database /path/to/gameplay.sqlite3`, then run
paired seeded games with the local Battlesnake CLI to measure win rate.

## Compact gameplay database
New gameplay turns use normalized storage: the turn row stores food, hazards,
move, and thinking data once; snake identity is stored once per game in
`game_snakes`; and changing snake state/body data lives in `snake_turns`. Replay
loading rebuilds the normal Battlesnake board payload.

Create and verify a separate compact copy of an existing SQLite database. By
default, replay-heavy rows are retained for games rated `medium` or `high` by
structural completeness, valid moves, thinking coverage, game length, move
diversity, opponent data, and terminal outcome. All game-result rows remain
stored, so historical win/loss rates stay persistent when low-quality replay
data is removed.
```sh
python scripts/migrate_gameplay_database.py \
  --source /path/to/gameplay.sqlite3 \
  --destination /path/to/gameplay.compact.sqlite3 \
  --minimum-quality medium
```

After reviewing the compact copy, `--replace` renames the original to a
timestamped backup and puts the verified compact database at the original path.
Stop all writers before using it:
```sh
python scripts/migrate_gameplay_database.py \
  --source /path/to/gameplay.sqlite3 \
  --replace
```

The migration never modifies the source in place. It verifies row counts and
runs SQLite's `integrity_check` before any replacement.

### Record new games while cleanup runs
Point the running server at a temporary delta database while the old database
is being compacted. After stopping the writer and flushing the delta database,
merge it into the cleaned copy:
```sh
python scripts/merge_gameplay_databases.py \
  --base /path/to/gameplay.compact.sqlite3 \
  --delta /path/to/gameplay.delta.sqlite3 \
  --destination /path/to/gameplay.merged.sqlite3 \
  --minimum-quality medium
```

The merger keeps all game results, quality-rates delta games, regenerates
numeric turn IDs, and verifies row counts, foreign keys, and database integrity.
Identical game IDs are skipped; conflicting duplicates abort the merge. After
reviewing the result, `--replace-base` backs up and replaces the cleaned base.
Stop the delta writer before the final merge and file swap.

## Export Training Dataset
Game saves now include a `dataset` section with labeled move samples.

Export all stored samples to JSONL:

```sh
python -m server.DatasetExporter --input data --output data/dataset/good_moves.jsonl
```

Or with `just`:

```sh
just export-dataset
```

Curate a high-quality training subset (single file):

```sh
python -m server.DatasetCurator --input good_moves-2026-04-03.jsonl --output data/dataset/best_moves.jsonl
```

Curate from multiple JSONL sources (repeat `--input`):

```sh
python -m server.DatasetCurator \
  --input good_moves-2026-04-03.jsonl \
  --input good_moves-2026-04-04.jsonl \
  --output data/dataset/best_moves.jsonl
```

Curate from folder or glob:

```sh
python -m server.DatasetCurator --input data/dataset --output data/dataset/best_moves.jsonl
python -m server.DatasetCurator --input "good_moves-*.jsonl" --output data/dataset/best_moves.jsonl
```

Append mode (keeps existing curated rows and deduplicates against them):

```sh
python -m server.DatasetCurator --input "good_moves-*.jsonl" --output data/dataset/best_moves.jsonl --append
```

Archive processed input files after curation:

```sh
python -m server.DatasetCurator --input "good_moves-*.jsonl" --output data/dataset/best_moves.jsonl --append --archive-input
python -m server.DatasetCurator --input "good_moves-*.jsonl" --output data/dataset/best_moves.jsonl --append --archive-input --archive-dir data/dataset/archive
```

Or with `just`:

```sh
just curate-dataset
just curate-dataset append=true
just curate-dataset append=true archive=true archive_dir=data/dataset/archive
```

Analyze dataset quality overall and by day (best game overall/day included):

```sh
python -m server.DatasetStats --input "good_moves-*.jsonl"
python -m server.DatasetStats --input data/dataset --output data/dataset/stats-report.json
```

The stats report now includes both:
- `best_game` (survival/length focused)
- `best_pressure_game` (high-pressure quality focused: fewer safe options + strong survival)

Or with `just`:

```sh
just analyze-dataset
just analyze-dataset input=data/dataset output=data/dataset/stats-report.json
```

To store compact dataset-only records (JSONL) and skip full per-game JSON files:

```sh
STORE_DATASET_ONLY=true DATASET_JSONL_PATH=data/dataset/good_moves.jsonl python main.py
```

Optional compact storage tuning:
- `DATASET_ROTATE_DAILY=true` creates one JSONL file per day (default: `true`)
- `DATASET_JSONL_MAX_MB=50` rotates when file reaches max size in MB (default: `50`)
- `DATASET_COMPRESS_ROTATED=true` gzip-compresses rotated/old JSONL files (default: `true`)

**Note:** To play games on [play.battlesnake.com](https://play.battlesnake.com) you'll need to deploy your Battlesnake to a live web server OR use a port forwarding tool like [ngrok](https://ngrok.com/) to access your server locally.