#!/bin/bash
# package-inventory - Compare archsetup packages vs live system
# Shows: packages in archsetup but missing from system,
#        packages on system but not in archsetup
#
# Usage: package-inventory [--archsetup-only | --system-only | --summary]

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
ARCHSETUP="$SCRIPT_DIR/archsetup"

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
CYAN='\033[0;36m'
BOLD='\033[1m'
NC='\033[0m'

# ============================================================================
# Extract packages from archsetup script
# ============================================================================
extract_archsetup_packages() {
    local tmp
    tmp=$(mktemp)

    # Extract pacman_install and aur_install calls (single package per line)
    grep -E '^\s*(pacman_install|aur_install)\s+' "$ARCHSETUP" \
        | grep -v '^\s*#' \
        | sed -E 's/^\s*(pacman_install|aur_install)\s+//' \
        | sed -E 's/\s*#.*//' \
        | sed 's/"//g' \
        | grep -v '^\$' \
        >> "$tmp"

    # Extract packages from for-loops: "for software in pkg1 pkg2 pkg3 ...; do"
    # These span multiple lines with backslash continuations
    awk '
    /for software in/ { capture=1; sub(/.*for software in/, ""); }
    capture {
        cont = ($0 ~ /\\$/)
        gsub(/\\/, "");
        gsub(/;.*/, "");
        gsub(/do$/, "");
        # Print each word as a package
        for (i=1; i<=NF; i++) {
            pkg = $i
            # Skip shell syntax
            if (pkg ~ /^\$|^#|^for|^in|^do|^done/) continue
            gsub(/"/, "", pkg)
            if (pkg != "") print pkg
        }
        if (!cont) capture=0
    }
    ' "$ARCHSETUP" >> "$tmp"

    # Extract pipx packages (these won't be in pacman -Qqe, note them separately)
    # Skip for now — pipx packages aren't pacman-managed

    sort -u "$tmp"
    rm -f "$tmp"
}

# ============================================================================
# Get packages on live system
# ============================================================================
get_system_packages_explicit() {
    pacman -Qqe | sort -u  # explicitly installed
}

get_system_packages_all() {
    pacman -Qq | sort -u   # all installed (including deps)
}

# ============================================================================
# Categorize system packages
# ============================================================================
get_system_native() {
    pacman -Qqen | sort -u  # native (official repos)
}

get_system_foreign() {
    pacman -Qqem | sort -u  # foreign (AUR/manual)
}

# ============================================================================
# Main comparison
# ============================================================================
main() {
    local mode="${1:-}"

    local archsetup_pkgs system_explicit system_all
    archsetup_pkgs=$(extract_archsetup_packages)
    system_explicit=$(get_system_packages_explicit)
    system_all=$(get_system_packages_all)

    # "not installed" = not on system at all (filters out dep-installed packages)
    # "not in archsetup" = explicitly installed but not declared in archsetup
    local missing_from_system missing_from_archsetup in_both
    missing_from_system=$(comm -23 <(echo "$archsetup_pkgs") <(echo "$system_all"))
    missing_from_archsetup=$(comm -13 <(echo "$archsetup_pkgs") <(echo "$system_explicit"))
    in_both=$(comm -12 <(echo "$archsetup_pkgs") <(echo "$system_explicit"))

    local archsetup_count system_count both_count missing_sys_count missing_arch_count
    archsetup_count=$(echo "$archsetup_pkgs" | wc -l)
    system_count=$(echo "$system_explicit" | wc -l)
    both_count=$(echo "$in_both" | grep -c . || true)
    missing_sys_count=$(echo "$missing_from_system" | grep -c . || true)
    missing_arch_count=$(echo "$missing_from_archsetup" | grep -c . || true)

    case "$mode" in
        --archsetup-only)
            echo "$missing_from_system"
            ;;
        --system-only)
            echo "$missing_from_archsetup"
            ;;
        --summary)
            print_summary "$archsetup_count" "$system_count" "$both_count" \
                "$missing_sys_count" "$missing_arch_count"
            ;;
        --help|-h)
            echo "Usage: package-inventory [OPTION]"
            echo ""
            echo "Compare packages in archsetup script vs installed on this system."
            echo ""
            echo "Options:"
            echo "  (none)            Full report with all sections"
            echo "  --archsetup-only  Packages in archsetup but not on system (plain list)"
            echo "  --system-only     Packages on system but not in archsetup (plain list)"
            echo "  --summary         Summary counts only"
            echo "  --help            This help message"
            ;;
        "")
            print_full_report "$archsetup_pkgs" "$system_explicit" \
                "$missing_from_system" "$missing_from_archsetup" "$in_both" \
                "$archsetup_count" "$system_count" "$both_count" \
                "$missing_sys_count" "$missing_arch_count"
            ;;
        *)
            echo "Unknown option: $mode" >&2
            echo "Run with --help for usage." >&2
            exit 1
            ;;
    esac
}

# ============================================================================
# Output formatting
# ============================================================================
print_summary() {
    local archsetup_count="$1" system_count="$2" both_count="$3"
    local missing_sys_count="$4" missing_arch_count="$5"

    echo -e "${BOLD}Package Inventory Summary${NC}"
    echo "─────────────────────────────────────"
    echo -e "  Archsetup declares:    ${CYAN}${archsetup_count}${NC} packages"
    echo -e "  System has installed:  ${CYAN}${system_count}${NC} packages (explicit)"
    echo -e "  In common:             ${GREEN}${both_count}${NC}"
    echo -e "  In archsetup, not system: ${YELLOW}${missing_sys_count}${NC}"
    echo -e "  On system, not archsetup: ${YELLOW}${missing_arch_count}${NC}"
}

print_full_report() {
    local archsetup_pkgs="$1" system_pkgs="$2"
    local missing_from_system="$3" missing_from_archsetup="$4" in_both="$5"
    local archsetup_count="$6" system_count="$7" both_count="$8"
    local missing_sys_count="$9" missing_arch_count="${10}"

    echo ""
    print_summary "$archsetup_count" "$system_count" "$both_count" \
        "$missing_sys_count" "$missing_arch_count"

    if [[ -n "$missing_from_system" ]]; then
        echo ""
        echo -e "${BOLD}${YELLOW}In archsetup but NOT installed on this system (${missing_sys_count}):${NC}"
        echo -e "${YELLOW}These may need installing, or are for a different desktop/hardware.${NC}"
        echo "─────────────────────────────────────"
        echo "$missing_from_system" | while read -r pkg; do
            echo "  $pkg"
        done
    fi

    if [[ -n "$missing_from_archsetup" ]]; then
        echo ""
        echo -e "${BOLD}${YELLOW}On system but NOT in archsetup (${missing_arch_count}):${NC}"
        echo -e "${YELLOW}Add to archsetup, or remove from system if no longer needed.${NC}"
        echo "─────────────────────────────────────"

        # Split into native and foreign for easier review
        local native foreign
        native=$(get_system_native)
        foreign=$(get_system_foreign)

        local foreign_extras native_extras
        foreign_extras=$(comm -12 <(echo "$missing_from_archsetup") <(echo "$foreign"))
        native_extras=$(comm -12 <(echo "$missing_from_archsetup") <(echo "$native"))

        local foreign_count native_count
        foreign_count=$(echo "$foreign_extras" | grep -c . || true)
        native_count=$(echo "$native_extras" | grep -c . || true)

        if [[ -n "$foreign_extras" ]]; then
            echo -e "  ${CYAN}AUR/foreign (${foreign_count}):${NC}"
            echo "$foreign_extras" | while read -r pkg; do
                echo "    $pkg"
            done
        fi

        if [[ -n "$native_extras" ]]; then
            echo -e "  ${CYAN}Official repos (${native_count}):${NC}"
            echo "$native_extras" | while read -r pkg; do
                echo "    $pkg"
            done
        fi
    fi

    echo ""
}

main "$@"