#!/bin/bash
set -euo pipefail

KEY_FILE="$HOME/.openai_api_key"
MODEL="gpt-4.1-nano"
MAX_TOKENS=100

# Display usage information
show_help() {
cat <<EOF
Usage: $(basename "$0") [description of the bash task]

Generates a bash command using OpenAI API and optionally runs it.

Options:
  -h, --help         Show this help message and exit
  -<flag>            Any argument starting with '-' will be sent directly as a prompt
                     instead of asking to output a bash command.

Environment Variables:
  OPENAI_API_KEY     Required. If not set, the script will prompt once and save to ~/.openai_api_key.
  VERBOSE=true       Optional. Enables debug output.

Examples:
  $(basename "$0") "list all files in /tmp modified in the last 24 hours"
  $(basename "$0") "restart nginx service if it's not running"
  $(basename "$0") -q "Explain the ls command options"   # sends directly to API
EOF
}

# Exit with help if no arguments or help flag is provided
if [[ $# -eq 0 || "$1" =~ ^-h|--help$ ]]; then
    show_help
    exit 0
fi

# Load API key from file if not already set
if [[ -z "${OPENAI_API_KEY:-}" && -f "$KEY_FILE" ]]; then
    OPENAI_API_KEY=$(<"$KEY_FILE")
fi

# Prompt for API key if still not set
if [[ -z "${OPENAI_API_KEY:-}" ]]; then
    read -s -p "Paste OpenAI API key: " OPENAI_API_KEY
    echo
    [[ -z "$OPENAI_API_KEY" ]] && echo "API key required" && exit 1
    echo "$OPENAI_API_KEY" > "$KEY_FILE"
    chmod 600 "$KEY_FILE"
fi

# Determine prompt and whether to skip command execution
if [[ "${1:0:1}" == "-" ]]; then
    prompt="$*"
    skip_run=true
else
    prompt="Only output the bash command to: $*"
    skip_run=false
fi

# Verbose output
if [[ "${VERBOSE:-}" == true ]]; then
    echo "[Verbose] Prompt: $prompt"
fi

# Generate JSON payload
json_payload=$(jq -n \
    --arg model "$MODEL" \
    --arg prompt "$prompt" \
    --argjson max_tokens "$MAX_TOKENS" \
    '{
        model: $model,
        messages: [{role:"user", content:$prompt}],
        temperature:0,
        max_tokens:$max_tokens
    }'
)

# Send request to OpenAI API
response=$(curl -sS https://api.openai.com/v1/chat/completions \
    -H "Authorization: Bearer $OPENAI_API_KEY" \
    -H "Content-Type: application/json" \
    -d "$json_payload"
)

# Extract command from API response
command=$(echo "$response" | jq -r '.choices[0].message.content // empty' | sed '/^```/d')
[[ -z "$command" ]] && echo "Failed to get command" && exit 1

echo -e "\nSuggested\n$command"

# Optionally run command
if [[ "$skip_run" != true ]]; then
    read -p "Run this command? (y/n): " confirm
    if [[ "$confirm" =~ ^[Yy]$ ]]; then
        eval "$command"
    else
        echo "Cancelled."
    fi
fi