#!/usr/bin/env bash
set -euo pipefail

script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
project_root="$(git -C "$script_dir" rev-parse --show-toplevel)"

if [[ -t 1 ]]; then
    c_reset=$'\033[0m'
    c_red=$'\033[31m'
    c_green=$'\033[32m'
    c_yellow=$'\033[33m'
else
    c_reset=''
    c_red=''
    c_green=''
    c_yellow=''
fi

ok() { printf '%sOK%s: %s\n' "$c_green" "$c_reset" "$*"; }
warn() { printf '%sWARN%s: %s\n' "$c_yellow" "$c_reset" "$*"; }
fail() { printf '%sFAIL%s: %s\n' "$c_red" "$c_reset" "$*" >&2; }

usage() {
    cat <<EOF
Usage: $(basename "$0") [--doctor] [--simulate-staleness] [--scan-dead-symlinks]

Check whether the compiled prefix libc.a is older than local fork commits.

Options:
  --doctor              Print verbose component/file diagnostics
  --simulate-staleness   Force an artificial stale-prefix result for testing
  --scan-dead-symlinks   Scan recipes/ for dangling symlinks and missing gitlinks
  -h, --help            Show this help
EOF
}

doctor=0
simulate_staleness=0
scan_dead_symlinks=0
for arg in "$@"; do
    case "$arg" in
        --doctor) doctor=1 ;;
        --simulate-staleness) simulate_staleness=1 ;;
        --scan-dead-symlinks) scan_dead_symlinks=1 ;;
        -h|--help) usage; exit 0 ;;
        *) fail "unknown argument: $arg"; usage; exit 2 ;;
    esac
done

scan_dead_symlinks_mode() {
    local broken=0 total=0 gitlink_count=0 path classification action target linkpath canonical
    local stale_recipe_overlay=0 stale_patch_symlink=0 stale_fork_symlink=0 stale_unclassified=0 stale_submodule=0

    while IFS= read -r linkpath; do
        [[ -n "$linkpath" ]] || continue
        (( total++ ))
        target=$(readlink "$project_root/$linkpath" || true)
        canonical=$(readlink -f "$project_root/$linkpath" 2>/dev/null || true)
        if [[ -z "$canonical" ]]; then
            canonical="$(python3 - <<'PY' "$project_root" "$linkpath" "$target"
import os, sys
root, linkpath, target = sys.argv[1:4]
print(os.path.normpath(os.path.join(os.path.dirname(os.path.join(root, linkpath)), target)))
PY
)"
        fi
        if [[ "$canonical" == "$project_root/local/recipes/"* ]]; then
            classification="stale recipe overlay"
            action="recreate or refresh the overlay under local/recipes/"
        elif [[ "$canonical" == "$project_root/local/patches/"* ]]; then
            classification="stale patch symlink"
            action="restore the patch file and rewire the recipe symlink"
        elif [[ "$canonical" == "$project_root/local/sources/"* ]]; then
            classification="stale fork symlink"
            action="restore the local fork source tree"
        else
            classification="stale symlink (unclassified)"
            action="inspect the target and repair the symlink"
        fi
        if [[ ! -e "$project_root/$linkpath" ]]; then
            printf '%s%s:1%s target=%s class=%s action=%s\n' "$c_red" "$linkpath" "$c_reset" "$target" "$classification" "$action"
            case "$classification" in
                "stale recipe overlay") (( stale_recipe_overlay++ )) ;;
                "stale patch symlink") (( stale_patch_symlink++ )) ;;
                "stale fork symlink") (( stale_fork_symlink++ )) ;;
                *) (( stale_unclassified++ )) ;;
            esac
            (( broken++ ))
        fi
    done < <(find "$project_root/recipes" -type l ! -exec test -e {} \; -print | sed "s#^$project_root/##")

    while IFS= read -r linkpath; do
        [[ -n "$linkpath" ]] || continue
        if [[ ! -e "$project_root/$linkpath" ]]; then
            printf '%s%s:1%s target=%s class=%s action=update submodule path or initialize submodule\n' "$c_red" "$linkpath" "$c_reset" "missing" "missing submodule path"
            (( stale_submodule++ ))
            (( broken++ ))
        fi
        (( gitlink_count++ ))
    done < <(git -C "$project_root" ls-tree -r --full-tree HEAD | awk '$1 == "160000" {print $4}')

    if (( broken )); then
        warn "dead symlink scan found $broken issue(s) across $total dangling link(s) and $gitlink_count gitlink(s)"
        printf '%sSummary:%s recipe overlay=%s patch symlink=%s fork symlink=%s unclassified=%s submodule=%s\n' \
            "$c_yellow" "$c_reset" "$stale_recipe_overlay" "$stale_patch_symlink" "$stale_fork_symlink" "$stale_unclassified" "$stale_submodule"
        return 1
    fi

    ok "dead symlink scan clean ($total dangling links checked, $gitlink_count gitlinks checked)"
}

latest_prefix_mtime() {
    local latest=0 path ts
    for path in \
        "$project_root/prefix/x86_64-unknown-redox/sysroot/x86_64-unknown-redox/lib/libc.a" \
        "$project_root/prefix/x86_64-unknown-redox/relibc-install/x86_64-unknown-redox/lib/libc.a"; do
        if [[ -e "$path" ]]; then
            ts=$(stat -c %Y "$path")
            (( ts > latest )) && latest=$ts
        fi
    done
    printf '%s' "$latest"
}

fork_mtime() {
    local path="$1"
    git -C "$project_root" log -1 --format=%ct -- "$path" 2>/dev/null || printf '0'
}

components=(relibc kernel base)
stale=0
prefix_ts="$(latest_prefix_mtime)"

if (( simulate_staleness )); then
    prefix_ts=0
fi

for component in "${components[@]}"; do
    path="local/sources/$component"
    fork_ts="$(fork_mtime "$path")"
    delta=$((fork_ts - prefix_ts))
    if (( doctor )); then
        printf '%s: fork=%s prefix=%s delta=%s\n' "$path" "$fork_ts" "$prefix_ts" "$delta"
    fi
    if (( fork_ts > prefix_ts )); then
        printf '%s: lib too old by %s seconds\n' "$component" "$delta"
        stale=1
    else
        ok "$component: prefix fresh"
    fi
done

if (( scan_dead_symlinks )); then
    if scan_dead_symlinks_mode; then
        exit 0
    fi
    exit 1
fi

if (( stale )); then
    warn "prefix is stale — run ./local/scripts/build-redbear.sh --upstream"
    exit 1
fi

ok "prefix is fresh"