#!/bin/bash

# Bring config options added to an app's template into an already-deployed copy.
#
# The deployed config at /docker/containers/<app>/<app>.config is written once,
# on first install, and never touched again — dockerConfigSetupToContainer only
# copies when the file is absent, precisely so a LibrePortal update can never
# overwrite the values someone has edited. That is the right default, but it has
# a consequence nobody chose: an app that gains a CFG_ option in a new release
# has that option on every FRESH install and on no EXISTING one.
#
# The failure is silent, which is the worst part. Nothing errors. The new key
# simply reads as empty, and whatever depends on it does something quietly
# different — a default it did not mean to take, or a value it needed and did
# not get. It only surfaces as "why does this work on my other box".
#
# So: copy across keys the template has and the deployed file does not, and
# nothing else.
#
# Deliberately NOT a merge or a regenerate. Rebuilding the deployed file from
# the template would place new keys in their proper section and refresh the
# documentation with them, which is genuinely nicer to read — but it would put a
# whole-file rewrite of every app's config in the path of every app action, and
# the worst case of a bug there is silently corrupting settings across the whole
# install. Appending cannot lose an existing line. That trade is not close.
#
# Existing keys are never touched, and keys the deployed file has but the
# template no longer does are left exactly where they are: a removed option is
# usually a rename, and deleting the user's value is not recoverable.

configBackfillMissingKeys()
{
    local app_name="$1"
    local template="$2"
    local deployed="$3"
    local silent_flag="${4:-silent}"

    [[ -f "$template" ]] || return 0
    [[ -f "$deployed" ]] || return 0

    # Same file, or a fresh copy of it — nothing can be missing.
    runFileOp cmp -s "$template" "$deployed" && return 0

    local template_keys deployed_keys missing
    template_keys=$(grep -oE '^CFG_[A-Z0-9_]+=' "$template" 2>/dev/null | sed 's/=$//' | sort -u)
    deployed_keys=$(runFileOp grep -oE '^CFG_[A-Z0-9_]+=' "$deployed" 2>/dev/null | sed 's/=$//' | sort -u)

    [[ -z "$template_keys" ]] && return 0

    missing=$(comm -23 <(printf '%s\n' "$template_keys") <(printf '%s\n' "$deployed_keys"))
    [[ -z "$missing" ]] && return 0

    # Carry each key's comment block over with it. A bare `CFG_X=value` appended
    # to the end of a heavily-documented file is an option nobody can act on;
    # the comment above it in the template is the only explanation that exists.
    local missing_csv
    missing_csv=$(printf '%s\n' "$missing" | paste -sd, -)

    local block
    block=$(awk -v keys="$missing_csv" '
        BEGIN { n = split(keys, K, ","); for (i = 1; i <= n; i++) want[K[i]] = 1 }
        # Accumulate the contiguous comment block sitting directly above a key.
        /^[[:space:]]*#/          { buf = buf $0 "\n"; next }
        # A blank line ends a block — the comments above it belong to something else.
        /^[[:space:]]*$/          { buf = ""; next }
        /^CFG_[A-Z0-9_]+=/ {
            k = $0; sub(/=.*/, "", k)
            if (k in want) printf "%s%s\n\n", buf, $0
            buf = ""
            next
        }
        { buf = "" }
    ' "$template")

    [[ -z "$block" ]] && return 0

    {
        printf '\n#\n'
        printf '# =============================================================================\n'
        printf '# ADDED BY A LIBREPORTAL UPDATE\n'
        printf '# =============================================================================\n'
        printf '# These options did not exist when this app was installed. They are set to the\n'
        printf '# defaults shipped with the new version — review them, they are yours to change.\n'
        printf '#\n'
        printf '%s\n' "$block"
    } | runFileWrite -a "$deployed"

    local count
    count=$(printf '%s\n' "$missing" | grep -c .)
    # Counter rather than a return code: the callers use this as a bare
    # statement, and a non-zero "nothing to do" would read as a failure to any
    # of them running under errexit.
    LP_BACKFILL_ADDED=$(( ${LP_BACKFILL_ADDED:-0} + count ))

    if [[ "$silent_flag" == "loud" ]]; then
        isSuccessful "Added $count new config option(s) to $app_name:"
        printf '%s\n' "$missing" | sed 's/^/    /'
    else
        isNotice "Added $count new config option(s) to $app_name's config."
    fi

    return 0
}

# Sweep every installed app after a LibrePortal update.
#
# The per-app backfill above only fires when an app's config is set up, which
# happens on install — and an update installs exactly one app, LibrePortal
# itself. So without this sweep, an option added to some app in a new release
# reaches that app only when someone next reinstalls it, which for a working app
# may be never. Since the whole point is that new options arrive on upgrade,
# upgrade is where this has to run.
configBackfillAllApps()
{
    local dir app template deployed
    LP_BACKFILL_ADDED=0

    # Driven from the template directory, not from the deployed one. Under
    # rootless the container tree is mode drwxr-x--x and owned by the docker
    # install user, so the manager running this can traverse it but cannot LIST
    # it — a glob over it silently expands to nothing and the sweep would report
    # success having examined no apps at all. The template dir is manager-owned
    # and readable, and it defines the same set of apps; whether each one is
    # actually installed is then just "does its deployed config exist", which is
    # a traverse, not a list.
    for dir in "$install_containers_dir"*/; do
        [[ -d "$dir" ]] || continue
        app="${dir%/}"; app="${app##*/}"
        [[ "$app" == "template" ]] && continue

        template="${dir}${app}.config"
        deployed="${containers_dir}${app}/${app}.config"
        [[ -f "$template" ]] || continue
        runFileOp test -f "$deployed" || continue

        configBackfillMissingKeys "$app" "$template" "$deployed" "silent"

        # A backfilled key whose default is a RANDOMIZED* placeholder has to be
        # given a real value here — nothing else will run over this file until
        # the app is next installed, and a placeholder left in place is a
        # credential that is identical on every install that took this upgrade.
        if runFileOp grep -qE 'RANDOMIZED(PASSWORD|USERNAME|BCRYPTPASSWORD|HEX|VAPID|APPKEY)[0-9]*' "$deployed" 2>/dev/null; then
            scanFileForRandomPasswordKeysUsers "$deployed"
        fi
    done

    if (( ${LP_BACKFILL_ADDED:-0} > 0 )); then
        isSuccessful "Carried $LP_BACKFILL_ADDED new config option(s) into your existing apps."
        isNotice "  They are set to the defaults shipped with this version — review them"
        isNotice "  in each app's Config tab."
    fi

    return 0
}