#!/usr/bin/env bash

# Exit immediately if a command exits with a non-zero status.
set -e
# Treat unset variables as an error when substituting.
set -u
# Pipestatus
set -o pipefail

# --- Configuration ---
: "${NIX_CONFIG_DIR:=/etc/nix-darwin}" # Path to your Nix configuration directory
: "${GIT_REMOTE_NAME:=origin}"
GIT_BRANCH_NAME_CMD="git -C \"$NIX_CONFIG_DIR\" rev-parse --abbrev-ref HEAD"
: "${GIT_BRANCH_NAME:=$(eval "$GIT_BRANCH_NAME_CMD" 2>/dev/null || echo main)}"

# Ollama configuration
: "${OLLAMA_MODEL:=deepseek-r1:1.5b}" # Ollama model
: "${OLLAMA_HOST:=http://localhost:11434}" # Default Ollama API host

# Hardcoded Nix switch command
NIX_SWITCH_COMMAND="sudo darwin-rebuild switch"
# If your flake requires a specific attribute, modify it here, e.g.:
# NIX_SWITCH_COMMAND="sudo darwin-rebuild switch --flake .#yourDarwinConfigName"
# --- End Configuration ---

# Function to check if a command exists
command_exists() {
    command -v "$1" >/dev/null 2>&1
}

# Check for dependencies
if ! command_exists ollama; then
    echo "❌ Error: ollama CLI not found. Please install Ollama."
    exit 1
fi
if ! command_exists jq; then
    echo "❌ Error: jq not found. Please install jq."
    exit 1
fi
if ! command_exists code; then
    echo "❌ Error: 'code' (VSCode CLI) not found. Please ensure it's in your PATH."
    echo "   You might need to install it from within VSCode (View -> Command Palette -> 'Shell Command: Install code command in PATH')."
    exit 1
fi
if ! command_exists sudo; then
    echo "❌ Error: 'sudo' command not found. This script requires sudo for 'darwin-rebuild switch'."
    exit 1
fi
if ! command_exists darwin-rebuild; then
    echo "❌ Error: 'darwin-rebuild' command not found. Please ensure Nix-Darwin is installed correctly."
    exit 1
fi


# --- VSCode Integration ---
echo "Nix config directory: $NIX_CONFIG_DIR"
echo "-----------------------------------------------------"
echo "💻 Opening VSCode to edit Nix configuration at $NIX_CONFIG_DIR..."
echo "   The script will continue after you close VSCode."

if ! code --wait "$NIX_CONFIG_DIR"; then
    echo "❌ Error: 'code --wait \"$NIX_CONFIG_DIR\"' failed."
    echo "   Please ensure VSCode is installed correctly and the 'code' command with '--wait' works."
    exit 1
fi
echo "✅ VSCode closed. Proceeding with the script..."
echo "-----------------------------------------------------"
# --- End VSCode Integration ---


# Function to generate commit message using Ollama
generate_commit_message() {
    local diff_content
    diff_content=$(git -C "$NIX_CONFIG_DIR" diff --staged)

    if [ -z "$diff_content" ]; then
        echo "chore: No changes to commit"
        return
    fi

    local max_diff_lines=150
    local truncated_diff
    truncated_diff=$(echo "$diff_content" | head -n "$max_diff_lines")
    if [ "$(echo "$diff_content" | wc -l)" -gt "$max_diff_lines" ]; then
        truncated_diff+=$'\n\n... (diff truncated) ...'
    fi

    local prompt
    prompt=$(cat <<EOF
You are an expert at writing Conventional Commit messages.
Analyze the following git diff from a Nix configuration repository (nix-darwin).
The configuration directory is: $NIX_CONFIG_DIR
Generate a concise and informative Conventional Commit message.

The commit message must follow this format:
<type>(<scope>): <subject>

[optional body]

[optional footer]

Allowed types:
- feat: A new feature or package addition
- fix: A bug fix in the configuration
- docs: Documentation changes
- style: Code style changes (formatting, whitespace)
- refactor: Code changes that neither fix a bug nor add a feature
- perf: A code change that improves performance
- test: Adding missing tests or correcting existing tests
- build: Changes that affect the build system or external dependencies
- ci: Changes to CI configuration files and scripts
- chore: Other changes that don't modify source or test files

Consider these for Nix configurations:
- Adding a new package: 'feat' or 'feat(pkg)' or 'feat(darwin)'
- Updating flake inputs: 'build(deps): update flake inputs' or 'chore(deps): update flake inputs'
- Modifying system settings: 'refactor(system)' or 'fix(system)'
- Changing themes or appearances: 'style(theme)'
- General maintenance or minor tweaks: 'chore' or 'refactor'

Focus on a short, descriptive subject line (max 50-70 chars).
If no specific scope is obvious, you can omit it.
If the changes are minor, 'chore' or 'refactor' are good defaults.

Git Diff:
---
$truncated_diff
---

Generate ONLY the commit message. Do not include any other explanatory text.
EOF
)

    echo "🧠 Generating commit message with Ollama ($OLLAMA_MODEL)..."
    local json_payload
    json_payload=$(jq -n \
                    --arg model "$OLLAMA_MODEL" \
                    --arg prompt "$prompt" \
                    '{
                        model: $model,
                        prompt: $prompt,
                        stream: false,
                        options: {
                            temperature: 0.3,
                            num_predict: 150
                        }
                    }')

    # Check if jq failed (e.g., if variables were not set properly for jq)
    if [ -z "$json_payload" ]; then
        echo "Error: Failed to create JSON payload with jq." >&2
        return
    fi

    local ollama_response
    ollama_response=$(curl -s --fail \
     -X POST \
     -H "Content-Type: application/json" \
     --data "$json_payload" \
     "$OLLAMA_HOST/api/generate")

    if [ -z "$ollama_response" ]; then
        echo "❌ Ollama request failed or returned empty. Using default commit message."
        echo "chore: Automated Nix config update $(date +'%Y-%m-%d %H:%M:%S')"
        return
    fi

    local generated_message
    generated_message=$(echo "$ollama_response" | jq -r '.response | sub("^\\s*"; "") | sub("\\s*$"; "")')

    if [ -z "$generated_message" ] || [[ "$generated_message" == "null" ]]; then
        echo "⚠️ Ollama did not return a valid message. Using default commit message."
        echo "chore: Automated Nix config update $(date +'%Y-%m-%d %H:%M:%S')"
    else
        if [[ "$generated_message" =~ ^[a-z]+(\([a-zA-Z0-9_-]+\))?!?: ]]; then
            echo "$generated_message"
        else
            echo "⚠️ Ollama message doesn't look like a conventional commit. Prepending 'chore: '."
            echo "chore: $generated_message"
        fi
    fi
}


echo "Current effective configuration:"
echo "Nix config directory: $NIX_CONFIG_DIR"
echo "Nix switch command to run: $NIX_SWITCH_COMMAND"
echo "Git remote: $GIT_REMOTE_NAME"
echo "Git branch: $GIT_BRANCH_NAME"
echo "Ollama model: $OLLAMA_MODEL"
echo "-----------------------------------------------------"

# 1. Navigate to the Nix config Git repository using pushd
#    This is done *before* the switch command so darwin-rebuild finds flake.nix
echo "🔄 Changing directory to $NIX_CONFIG_DIR using pushd..."
if ! pushd "$NIX_CONFIG_DIR" > /dev/null; then
    echo "❌ Failed to pushd into $NIX_CONFIG_DIR. Is the path correct and accessible?"
    exit 1
fi
echo "✅ Successfully changed to $NIX_CONFIG_DIR (current directory: $PWD)."
echo "-----------------------------------------------------"

# Ensure we popd at the end, even if errors occur.
# A trap is more robust, but for now, manual popd before exits and at the end.
_cleanup() {
    echo "🔄 Returning to original directory using popd..."
    if ! popd > /dev/null; then
        echo "⚠️ Failed to popd. Current directory ($PWD) might not be the original one."
    fi
}
# trap _cleanup EXIT # Uncomment this for more robust cleanup on any exit

# 2. Run the Nix switch command
echo "🚀 Starting Nix switch: $NIX_SWITCH_COMMAND"
echo "   This command will be run from: $PWD"
# The '|| echo ...' construct ensures the script continues even if the command fails,
# due to 'set -e'. A warning will be printed on failure.
# Using 'eval' to correctly handle the command string if it contains spaces and needs sudo.
eval "$NIX_SWITCH_COMMAND" || echo "⚠️ Nix switch command exited with a non-zero status. Continuing as requested..."
echo "ℹ️ Nix switch command execution finished. Proceeding..."
echo "-----------------------------------------------------"

# 3. Check for changes
echo "🔍 Checking for Git changes in current directory ($PWD)..."
if git diff --quiet && git diff --staged --quiet; then
    echo "ℹ️ No changes detected in $NIX_CONFIG_DIR. Nothing to commit or push."
    _cleanup # Call cleanup function
    exit 0
fi
echo "✅ Changes detected."
echo "-----------------------------------------------------"

# 4. Add changes
echo "💾 Staging all changes in current directory ($PWD)..."
git add .
echo "-----------------------------------------------------"

# 5. Generate Commit Message
COMMIT_MESSAGE=$(generate_commit_message) # generate_commit_message uses git -C "$NIX_CONFIG_DIR"
echo "💬 Generated commit message:"
echo "$COMMIT_MESSAGE"
echo "-----------------------------------------------------"

# 6. Commit and Push
echo "✍️ Committing to local repository in current directory ($PWD)..."
if printf '%s\n' "$COMMIT_MESSAGE" | git commit -F - ; then
    echo "✅ Commit successful."
else
    echo "❌ Git commit failed. Please check the repository status and the generated message."
    echo "   Ensure you have commit permissions for $NIX_CONFIG_DIR."
    _cleanup # Call cleanup function
    exit 1
fi

echo "📡 Pushing to $GIT_REMOTE_NAME $GIT_BRANCH_NAME from current directory ($PWD)..."
if ! git push "$GIT_REMOTE_NAME" "$GIT_BRANCH_NAME"; then
    echo "⚠️ Git push failed. The commit was made locally, but not pushed."
    echo "   Please check your remote connection, permissions, and push manually if needed."
else
    echo "✅ Push successful."
fi
echo "-----------------------------------------------------"

_cleanup # Call cleanup function
echo "🎉 All done!"