#!/bin/bash
# Shim managed by BVM (Bun Version Manager)
# Optimized for performance via Bash-native syntax.

BVM_DIR="${BVM_DIR:-$HOME/.bvm}"
CMD_NAME="$1"
shift

if [ -z "$CMD_NAME" ]; then
    echo "BVM Error: No command specified." >&2
    exit 1
fi

# --- 1. Fast Path: Active Version or Local .bvmrc ---
if [ -n "$BVM_ACTIVE_VERSION" ]; then
    VERSION="$BVM_ACTIVE_VERSION"
elif [ -f ".bvmrc" ]; then
    # Read first line, strip whitespace and 'v' prefix using pure Bash
    read -r raw_ver < .bvmrc
    VERSION="v${raw_ver//[v[:space:]]/}"
fi

# --- 2. Slow Path: Recursive .bvmrc Search or Default ---
if [ -z "$VERSION" ]; then
    CUR_DIR="$PWD"
    while [ "$CUR_DIR" != "/" ] && [ -n "$CUR_DIR" ]; do
        if [ -f "$CUR_DIR/.bvmrc" ]; then
            read -r raw_ver < "$CUR_DIR/.bvmrc"
            VERSION="v${raw_ver//[v[:space:]]/}"
            break
        fi
        CUR_DIR=$(dirname "$CUR_DIR")
    done

    # Fallback to current symlink (most common production case)
    if [ -z "$VERSION" ] && [ -L "$BVM_DIR/current" ]; then
        VERSION_PATH=$(readlink "$BVM_DIR/current")
        VERSION="${VERSION_PATH##*/}"
    fi

    # Fallback to default alias
    if [ -z "$VERSION" ] && [ -f "$BVM_DIR/aliases/default" ]; then
        read -r raw_ver < "$BVM_DIR/aliases/default"
        VERSION="${raw_ver//[[:space:]]/}"
    fi
fi

if [ -z "$VERSION" ]; then
    echo "BVM Error: No Bun version active." >&2
    exit 1
fi

# Ensure 'v' prefix
[[ "$VERSION" != v* ]] && VERSION="v$VERSION"
VERSION_DIR="$BVM_DIR/versions/$VERSION"
REAL_EXECUTABLE="$VERSION_DIR/bin/$CMD_NAME"

if [ -x "$REAL_EXECUTABLE" ]; then
    export BUN_INSTALL="$VERSION_DIR"
    export PATH="$VERSION_DIR/bin:$PATH"
    
    # Inject version-specific config if present
    if [ -f "$VERSION_DIR/bunfig.toml" ]; then
        export BUN_CONFIG_FILE="$VERSION_DIR/bunfig.toml"
    fi
    
    # Execute the command
    "$REAL_EXECUTABLE" "$@"
    EXIT_CODE=$?

    # Auto-Rehash Logic
    if [ "$CMD_NAME" = "bun" ] && [ $EXIT_CODE -eq 0 ]; then
        case "$1" in
            install|i|add|a|remove|rm|upgrade|link|unlink)
                (export BVM_DIR="$BVM_DIR"; "$BVM_DIR/bin/bvm" rehash --silent >/dev/null 2>&1 & disown)
                ;;
        esac
    fi
    
    exit $EXIT_CODE
elif [ "$CMD_NAME" = "bunx" ] && [ -x "$VERSION_DIR/bin/bun" ]; then
    export BUN_INSTALL="$VERSION_DIR"
    export PATH="$VERSION_DIR/bin:$PATH"
    exec "$VERSION_DIR/bin/bun" x "$@"
else
    echo "BVM Error: Command '$CMD_NAME' not found in Bun $VERSION." >&2
    exit 127
fi