#!/usr/bin/env bash

set -euo pipefail
shopt -s nullglob

repoDir="/var/www/packages.stormux.org"
aurRpcUrl="https://aur.archlinux.org/rpc/v5/info"
exclude=("gzdoom")

require_cmd() {
    local cmd="$1"

    if ! command -v "$cmd" >/dev/null 2>&1; then
        printf 'Required command not found: %s\n' "$cmd" >&2
        exit 1
    fi
}

is_excluded() {
    local packageName="$1"
    local excludedPackage

    for excludedPackage in "${exclude[@]}"; do
        if [[ "$excludedPackage" == "$packageName" ]]; then
            return 0
        fi
    done

    return 1
}

record_local_package_version() {
    local packageName="$1"
    local packageVersion="$2"
    local packageMapName="$3"
    local -n packageMapRef="$packageMapName"
    local existingVersion="${packageMapRef[$packageName]:-}"

    if [[ -z "$existingVersion" ]] || (( $(vercmp "$packageVersion" "$existingVersion") > 0 )); then
        packageMapRef["$packageName"]="$packageVersion"
    fi
}

read_package_metadata() {
    local packageFile="$1"

    pacman -Qip "$packageFile" | parse_pacman_info
}

parse_pacman_info() {
    awk '
        /^Name[[:space:]]*:/ {
            packageName=$0
            sub(/^Name[[:space:]]*:[[:space:]]*/, "", packageName)
        }
        /^Version[[:space:]]*:/ {
            packageVersion=$0
            sub(/^Version[[:space:]]*:[[:space:]]*/, "", packageVersion)
        }
        END {
            if (packageName == "" || packageVersion == "") {
                exit 1
            }

            printf "%s\t%s\n", packageName, packageVersion
        }
    '
}

collect_local_packages() {
    local packageMapName="$1"
    # shellcheck disable=SC2178
    local -n packageMapRef="$packageMapName"
    local archDir packageFile metadata packageName packageVersion
    local -a archDirs=("$repoDir/x86_64" "$repoDir/aarch64")

    for archDir in "${archDirs[@]}"; do
        if [[ ! -d "$archDir" ]]; then
            continue
        fi

        for packageFile in "$archDir"/*.pkg.tar.zst "$archDir"/*.pkg.tar.xz; do
            metadata="$(read_package_metadata "$packageFile")" || {
                printf 'Unable to read package metadata: %s\n' "$packageFile" >&2
                exit 1
            }

            packageName="${metadata%%$'\t'*}"
            packageVersion="${metadata#*$'\t'}"
            record_local_package_version "$packageName" "$packageVersion" "$packageMapName"
        done
    done
}

extract_aur_version_from_json() {
    local packageName="$1"

    jq -r --arg packageName "$packageName" '
        .results[]
        | select(.Name == $packageName)
        | .Version
    ' | head -n1
}

fetch_aur_version() {
    local packageName="$1"

    curl -fsS --get \
        --data-urlencode "arg[]=${packageName}" \
        "$aurRpcUrl" |
        extract_aur_version_from_json "$packageName"
}

print_outdated_packages() {
    local packageMapName="$1"
    # shellcheck disable=SC2178
    local -n packageMapRef="$packageMapName"
    local packageName localVersion aurVersion
    local -a packageNames=()

    mapfile -t packageNames < <(printf '%s\n' "${!packageMapRef[@]}" | sort)

    for packageName in "${packageNames[@]}"; do
        if is_excluded "$packageName"; then
            continue
        fi

        localVersion="${packageMapRef[$packageName]}"
        aurVersion="$(fetch_aur_version "$packageName" || true)"

        if [[ -z "$aurVersion" ]]; then
            continue
        fi

        if (( $(vercmp "$localVersion" "$aurVersion") < 0 )); then
            printf '%s %s\n' "$packageName" "$aurVersion"
        fi
    done
}

assert_equals() {
    local expected="$1"
    local actual="$2"
    local message="$3"

    if [[ "$expected" != "$actual" ]]; then
        printf 'FAIL: %s\nExpected: %s\nActual: %s\n' "$message" "$expected" "$actual" >&2
        exit 1
    fi
}

assert_success() {
    local message="$1"
    shift

    if ! "$@"; then
        printf 'FAIL: %s\n' "$message" >&2
        exit 1
    fi
}

assert_failure() {
    local message="$1"
    shift

    if "$@"; then
        printf 'FAIL: %s\n' "$message" >&2
        exit 1
    fi
}

main() {
    if [[ "${1:-}" == "--self-test" ]]; then
        run_self_tests
        return
    fi

    require_cmd "curl"
    require_cmd "jq"
    require_cmd "pacman"
    require_cmd "vercmp"

    if [[ ! -d "$repoDir" ]]; then
        printf 'Repo dir does not exist: %s\n' "$repoDir" >&2
        exit 1
    fi

    # shellcheck disable=SC2034
    declare -A localPackages=()
    collect_local_packages localPackages
    print_outdated_packages localPackages
}

run_self_tests() {
    declare -A packageMap=()
    local exactMatchJson noMatchJson
    local extractedVersion=""
    local pacmanInfo=""

    assert_success "excluded package should match" is_excluded "gzdoom"
    assert_failure "non-excluded package should not match" is_excluded "fenrir"

    record_local_package_version "fenrir" "1:2026.01.20-1" packageMap
    record_local_package_version "fenrir" "1:2026.01.28-1" packageMap
    record_local_package_version "fenrir" "1:2026.01.10-1" packageMap
    assert_equals "1:2026.01.28-1" "${packageMap[fenrir]}" "newest local version should win"

    exactMatchJson='{"results":[{"Name":"fenrir-git","Version":"1:r3322.4672592d-1"},{"Name":"fenrir","Version":"1:2026.01.28-1"}]}'
    extractedVersion="$(printf '%s\n' "$exactMatchJson" | extract_aur_version_from_json "fenrir")"
    assert_equals "1:2026.01.28-1" "$extractedVersion" "exact package name should be selected from AUR JSON"

    noMatchJson='{"results":[{"Name":"fenrir-git","Version":"1:r3322.4672592d-1"}]}'
    extractedVersion="$(printf '%s\n' "$noMatchJson" | extract_aur_version_from_json "fenrir")"
    assert_equals "" "$extractedVersion" "missing exact AUR match should stay empty"

    pacmanInfo='Name            : fenrir
Version         : 1:2026.01.28-1
Description     : A user space console screen reader written in python3'
    extractedVersion="$(printf '%s\n' "$pacmanInfo" | parse_pacman_info)"
    assert_equals $'fenrir\t1:2026.01.28-1' "$extractedVersion" "pacman metadata parsing should return name and version"

    if (( $(vercmp "1:2026.01.20-1" "1:2026.01.28-1") >= 0 )); then
        printf 'FAIL: older local version should compare lower than AUR version\n' >&2
        exit 1
    fi

    printf 'Self-test passed\n'
}

main "$@"