Cocom is a powerful, terminal-based companion for competitive programming. It seamlessly integrates with the Competitive Companion browser extension to fetch problem statements, generate smart boilerplate, resolve custom library dependencies, and locally judge your solutions against sample test cases—all without leaving your terminal.

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Features

• Competitive Companion Server: Local HTTP endpoint (127.0.0.1:6174) to receive problem metadata, constraints, and sample tests directly from the browser extension.
• Regex-Based File Routing: Maps problem URLs to local directory structures and filenames using configurable regex captures and Go templates.
• Snippet Linker: Parses custom @head and @code tags in your local library, topologically sorts dependencies, and merges them into the final submission payload.
• Watch & Run: Filesystem watcher that automatically detects file saves, compiles the code, and pipes sample tests to the binary.
• Sandboxed Execution: Compiles and runs code in an isolated temporary directory with strict time limits (context.WithTimeout) and peak memory tracking (syscall.Rusage).
• Split-Pane TUI: Bubble Tea interface with viewports to diff Input, Expected Output, Actual Output, and StdErr side-by-side.
• Silent Logging: Non-blocking structured logs written to the OS temp directory to debug HTTP payloads, linker graphs, and compiler stderr.

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🎥 Demo

Preview with Zed

Tip: Press f to switch to the editor

Example workflow using Neovim

Tip: Press f to edit the file again

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Example workflow using Vscode

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🚀 Installation

Ensure you have Go installed (v1.22+ recommended).

go install github.com/veryshyjelly/cocom@latest

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🛠️ Usage

Run cocom in your competitive programming workspace root.

cocom [options]

CLI Options

Flag	Description	Default
-c, --config <file>	Path to the configuration file.	./cocom.yml
-C, --root <dir>	Project root directory.	. (Current Dir)
-d, --debug	Enable verbose debug logging.	false
-v, --version	Show version information.	false
-h, --help	Show help message.	false

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⚙️ Configuration (cocom.yml)

If cocom.yml is not found, Cocom will prompt you to generate a starter template. Below is an example configuration for OCaml:

author: YOUR_NAME_HERE

# Command to open the generated file in your favorite editor
editor: "code {{ .Filename }}" 

# Rules for generating filenames based on problem URLs
filename:
  rules:
    - site: codeforces.com
      regex: "(?:problemset/problem|contest|gym)/(\\d+)(?:/problem)?/([A-Za-z0-9]+)"
      template: './src/bin/{{ index .Captures 1 }}-{{ index .Captures 2 }}-{{ .Title | stripPrefix "."  | toKebabCase }}.rs'
      
    - site: atcoder.jp
      regex: "contests/([^/]+)/tasks/([^_]+)_([a-z]+)"
      template: './src/bin/{{ index .Captures 2 }}-{{ index .Captures 3 | toLowerCase }}{{if gt (.Title | stripPrefix "-" | len) 0}}-{{ .Title | stripPrefix "-"  | toKebabCase }}{{- end -}}.rs'

# Base template for newly created files
template:
  source: ./src/main.ml
  modifier: |
    (* Created by {{ .Author }} at {{ .Time }} 
       {{ .Url }} *)
    {{ .Code }}

# Post-processor for the final submitted code
code:
  modifier: |
    {{ .Header }}
    {{ range .LibFiles }}
    (* --- {{ .Name }} --- *)
    {{ .Content }}
    {{ end }}
    {{ .Code }}

# Custom library linking
lib:
  # Regex template to detect library usage in code
  regex: "open {{ .Name }}"
  include:
    dsu: "./src/lib/dsu.ml"
    math: "./src/lib/math.ml"

# Compiler and execution settings
compiler:
  name: Ocaml
  source: "main.ml"       # Name of the sandbox file
  compile: ocamlfind      # Leave empty for interpreted languages (Python, etc.)
  args:
    - ocamlopt
    - -O2
    - -o
    - a.out
    - main.ml
    - -linkpkg
    - -thread
    - -package
    - str,num,zarith,threads,containers,core,iter,batteries
  run: ./a.out

# Behavior toggles
create_file: true   # Auto-create boilerplate file on problem fetch
run_on_save: true   # Auto-run tests when the file watcher detects changes

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⌨️ Keybindings

Keys	Action
r / Ctrl+'	Run test cases manually
f	Create boilerplate file
c	Copy solution file
a	Add custom test case
q / Esc / Ctrl+C	Quit application
1 / j	View: Input & Answer
2 / k	View: Input & Output
3 / l	View: Input & Error
4 / ;	View: Answer & Output
→ / Tab	Next test case
← / Shift+Tab	Previous test case
?	Toggle Help menu

(Note: Mouse scrolling and clicking are also fully supported in the split-pane viewports!)

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📂 How the Custom Linker Works

Cocom features a unique dependency linker for your personal snippet libraries, acting like a mini-compiler frontend:

1. It scans your configured lib.include files.
2. It uses the lib.regex to build a dependency graph (e.g., if graph.ml contains open DSU, it depends on dsu.ml).
3. It performs a Topological Sort (DFS) to ensure dependencies are injected before the files that need them. Detects and prevents cyclic dependencies!
4. It extracts headers (@head begin ... @head end) and code blocks (@code begin ... @code end) to cleanly merge them into your final sandbox solution without polluting your local workspace files.

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🪵 Logging & Debugging

Cocom runs a comprehensive background logger to help you debug parsing, linking, or compilation issues without cluttering your TUI.

• Location: <OS_TEMP_DIR>/cocom.log (e.g., /tmp/cocom.log on Linux/macOS).
• Levels: DEBUG (run with -d flag), INFO, and ERROR.
• Logs include incoming HTTP JSON payloads, dependency graph resolutions, compilation stderr, and sandbox execution metrics.

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🤝 Contributing

Contributions, issues, and feature requests are welcome! Feel free to check the issues page.

📄 License

This project is licensed under the MIT License.