#!/bin/bash
# Upgrade script for Claude Code configuration
# Usage: ./upgrade.sh [--check|--backup|--apply]

set -euo pipefail

CLAUDE_DIR="${HOME}/.claude"
VERSION_FILE="${CLAUDE_DIR}/VERSION"
BACKUP_DIR="${CLAUDE_DIR}/backups"

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

info() { echo -e "${BLUE}ℹ${NC} $1"; }
ok() { echo -e "${GREEN}✓${NC} $1"; }
warn() { echo -e "${YELLOW}⚠${NC} $1"; }
error() { echo -e "${RED}✗${NC} $1"; }

get_current_version() {
    if [[ -f "$VERSION_FILE" ]]; then
        cat "$VERSION_FILE" | tr -d '\n'
    else
        echo "0.0.0"
    fi
}

compare_versions() {
    local v1="$1"
    local v2="$2"

    # Returns: -1 if v1 < v2, 0 if equal, 1 if v1 > v2
    if [[ "$v1" == "$v2" ]]; then
        echo "0"
        return
    fi

    local IFS='.'
    local i v1_parts=($v1) v2_parts=($v2)

    for ((i=0; i<3; i++)); do
        local v1_part="${v1_parts[i]:-0}"
        local v2_part="${v2_parts[i]:-0}"

        if ((v1_part > v2_part)); then
            echo "1"
            return
        elif ((v1_part < v2_part)); then
            echo "-1"
            return
        fi
    done

    echo "0"
}

check_upgrade() {
    local current=$(get_current_version)

    echo ""
    echo "🔍 Checking for upgrades..."
    echo ""
    echo "  Current version: $current"
    echo ""

    # Check git status if in a repo
    if [[ -d "${CLAUDE_DIR}/.git" ]]; then
        cd "$CLAUDE_DIR"

        # Fetch latest
        if git fetch origin 2>/dev/null; then
            local local_hash=$(git rev-parse HEAD 2>/dev/null || echo "unknown")
            local remote_hash=$(git rev-parse origin/main 2>/dev/null || echo "unknown")

            if [[ "$local_hash" != "$remote_hash" ]] && [[ "$remote_hash" != "unknown" ]]; then
                local ahead=$(git rev-list --count origin/main..HEAD 2>/dev/null || echo "0")
                local behind=$(git rev-list --count HEAD..origin/main 2>/dev/null || echo "0")

                if [[ "$behind" -gt 0 ]]; then
                    warn "Behind origin/main by $behind commit(s)"
                    echo ""
                    echo "  Run: cd ~/.claude && git pull"
                fi

                if [[ "$ahead" -gt 0 ]]; then
                    info "Ahead of origin/main by $ahead commit(s)"
                fi
            else
                ok "Up to date with origin/main"
            fi
        else
            warn "Could not fetch from remote"
        fi
    else
        info "Not a git repository - manual upgrade required"
    fi

    echo ""
}

pre_upgrade_backup() {
    echo ""
    echo "📦 Creating pre-upgrade backup..."

    mkdir -p "$BACKUP_DIR"
    local timestamp=$(date +%Y%m%d-%H%M%S)
    local backup_file="${BACKUP_DIR}/pre-upgrade-${timestamp}.tar.gz"

    # Backup essential files only
    tar -czf "$backup_file" \
        -C "$CLAUDE_DIR" \
        --exclude='backups' \
        --exclude='logs' \
        --exclude='*.pyc' \
        --exclude='__pycache__' \
        --exclude='.git' \
        --exclude='venv' \
        . 2>/dev/null || true

    ok "Backup created: $backup_file"
    echo ""
}

apply_migrations() {
    local current="$1"
    local target="$2"

    echo ""
    echo "🔄 Applying migrations from $current to $target..."
    echo ""

    # Migration: 0.x.x -> 1.0.0
    if [[ $(compare_versions "$current" "1.0.0") -lt 0 ]] && \
       [[ $(compare_versions "$target" "1.0.0") -ge 0 ]]; then
        info "Migration: Initializing plugin structure..."

        # Create directories if missing
        mkdir -p "${CLAUDE_DIR}/.claude-plugin"
        mkdir -p "${CLAUDE_DIR}/hooks/scripts"
        mkdir -p "${CLAUDE_DIR}/state/personal-assistant/memory"
        mkdir -p "${CLAUDE_DIR}/state/personal-assistant/history"

        ok "Plugin structure initialized"
    fi

    # Migration: 1.0.x -> 1.1.0
    if [[ $(compare_versions "$current" "1.1.0") -lt 0 ]] && \
       [[ $(compare_versions "$target" "1.1.0") -ge 0 ]]; then
        info "Migration: Adding automation scripts..."

        # Ensure automation directory exists
        mkdir -p "${CLAUDE_DIR}/automation/systemd"
        mkdir -p "${CLAUDE_DIR}/logs"

        ok "Automation structure initialized"
    fi

    echo ""
    ok "Migrations complete"
}

run_post_upgrade() {
    echo ""
    echo "🔧 Running post-upgrade tasks..."

    # Make scripts executable
    find "${CLAUDE_DIR}/automation" -name "*.sh" -type f -exec chmod +x {} \; 2>/dev/null || true
    find "${CLAUDE_DIR}/automation" -name "*.py" -type f -exec chmod +x {} \; 2>/dev/null || true
    find "${CLAUDE_DIR}/hooks/scripts" -name "*.sh" -type f -exec chmod +x {} \; 2>/dev/null || true

    ok "Scripts made executable"

    # Validate
    if "${CLAUDE_DIR}/automation/validate-setup.sh" > /dev/null 2>&1; then
        ok "Validation passed"
    else
        warn "Validation had warnings (run claude-validate to see details)"
    fi

    echo ""
}

show_usage() {
    echo "Usage: $0 [--check|--backup|--apply TARGET_VERSION]"
    echo ""
    echo "Options:"
    echo "  --check    Check for available upgrades"
    echo "  --backup   Create pre-upgrade backup"
    echo "  --apply    Apply migrations (requires TARGET_VERSION)"
    echo ""
    echo "Examples:"
    echo "  $0 --check"
    echo "  $0 --backup && git pull && $0 --apply 1.2.0"
}

# Main
case "${1:-}" in
    --check)
        check_upgrade
        ;;
    --backup)
        pre_upgrade_backup
        ;;
    --apply)
        if [[ -z "${2:-}" ]]; then
            error "TARGET_VERSION required for --apply"
            show_usage
            exit 1
        fi
        pre_upgrade_backup
        apply_migrations "$(get_current_version)" "$2"
        echo "$2" > "$VERSION_FILE"
        run_post_upgrade
        ok "Upgrade to $2 complete!"
        ;;
    --help|-h)
        show_usage
        ;;
    *)
        check_upgrade
        ;;
esac