# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Build Commands

```bash
fpm build                          # Debug build
fpm build --flag "-O2"             # Release build with optimization
fpm build --flag "-g -Wall -Wextra" # Build with debug flags and warnings
fpm run                            # Build and run
fpm test                           # Run test suite
```

**Dependencies**: gfortran 10+ (or ifort), fpm, ncurses library

## Architecture

FORTRESS is a CLI file manager written in modern Fortran (2008+) with dual-pane navigation, git integration, and fuzzy search.

### Module Structure

```
app/main.f90              # Main event loop, state management, user input (~1100 LOC)
src/
├── filesystem/fs_ops.f90     # Directory reading, path manipulation, fzf search, file ops
├── ui/display.f90            # Dual-pane rendering (30% parent | 70% current), color output
├── ui/preview.f90            # File preview functionality
├── terminal/term_control.f90 # Raw mode, ANSI codes, terminal size, key reading
├── git/git_ops.f90           # Git status, staging, commits, push/pull, diff display
└── version/version.f90       # Version info (auto-generated by stamp-version.sh)
```

### Key Patterns

**State Management**: The main event loop in `main.f90` manages:
- Navigation state (`current_dir`, `parent_dir`, `selected`, `scroll_offset`)
- Mode flags (`move_mode`, `in_rename_mode`, `in_selection_mode`)
- Clipboard (`has_clipboard`, `clipboard_paths[]`, copy vs cut)
- Multi-select tracking (`is_selected[]`, `selection_count`)
- Favorites stored in `~/.fortress_favorites`

**Terminal Control**:
- Uses alternate screen buffer (`ESC[?1049h/l`) to prevent scroll artifacts
- Raw mode via `stty` for non-blocking, character-by-character input
- Terminal size caching (refreshes every 100 calls)

**External Commands**: All shell commands use `execute_command_line()` - ensure proper escaping for paths with special characters.

**Git Integration**: Uses git CLI directly; status is cached with 500ms TTL. Directories show recursive status indicators.

**Shell Integration**: `~/.fortress_cd` file enables cd-on-exit feature; wrapper scripts in `fortress.sh`/`fortress.fish` read this file.

### Constants

Defined across modules: `MAX_PATH=512`, `MAX_FILES=500`

### Color Scheme

Blue=directories, Green=executables, Grey=dotfiles, Red=cut files/staged, Yellow=warnings/incoming changes