Refactor helper modules for im0

11 files changed, 503 insertions, 495 deletions

diff --git a/Justfile b/Justfile
index 2c0c0b6..841cfb8 100644
--- a/Justfile
+++ b/Justfile
@@ -7,7 +7,7 @@ PREFIX := env_var_or_default("PREFIX", "/usr")
 BINDIR := env_var_or_default("BINDIR", PREFIX + "/bin")
 DATADIR := env_var_or_default("DATADIR", PREFIX + "/share")
 SYSCONFDIR := env_var_or_default("SYSCONFDIR", "/etc/default")
-LIB_SOURCES := "src/lib/bootstrap.source.sh src/lib/system.source.sh src/lib/template.source.sh src/lib/image.source.sh src/lib/album.source.sh src/lib/config.source.sh src/lib/config.print.source.sh src/lib/config.sync.source.sh src/lib/config.staging.source.sh src/lib/config.validate.source.sh src/lib/config.cli.source.sh src/lib/action.source.sh"
+LIB_SOURCES := "src/lib/bootstrap.source.sh src/lib/imagemagick.source.sh src/lib/process.source.sh src/lib/archive.source.sh src/lib/template.source.sh src/lib/job-pool.source.sh src/lib/image.source.sh src/lib/random.source.sh src/lib/album.source.sh src/lib/config.source.sh src/lib/config.print.source.sh src/lib/config.sync.source.sh src/lib/config.staging.source.sh src/lib/config.validate.source.sh src/lib/config.cli.source.sh src/lib/action.source.sh"
 
 default: build
 
diff --git a/bin/shuriken b/bin/shuriken
index b37aad3..afad2f4 100755
--- a/bin/shuriken
+++ b/bin/shuriken
@@ -268,7 +268,7 @@ init_config() {
     log_info "Created ./$rc_file"
 }
 
-# Inlined from src/lib/system.source.sh
+# Inlined from src/lib/imagemagick.source.sh
 # shellcheck disable=SC2034
 resolve_imagemagick_command() {
     local -r operation="$1"; shift
@@ -341,6 +341,7 @@ imagemagick_identify() {
         "${imagemagick_command[@]}" "$@"
 }
 
+# Inlined from src/lib/process.source.sh
 run_with_timeout() {
     local -r description="$1"; shift
     local -r seconds="$1"; shift
@@ -366,6 +367,7 @@ run_with_timeout() {
     return "$status"
 }
 
+# Inlined from src/lib/archive.source.sh
 tarball() {
     local -r tarball_name="$1"; shift
     local -r tarball_suffix="$TARBALL_SUFFIX"
@@ -419,29 +421,6 @@ resolve_tar_opts() {
     fi
 }
 
-resolve_sync_destinations() {
-    local -n destinations_ref="$1"; shift
-    local destinations_decl
-
-    destinations_ref=()
-
-    if ! destinations_decl=$(declare -p SYNC_DESTINATIONS 2>/dev/null); then
-        return
-    fi
-
-    case "$destinations_decl" in
-        declare\ -a*\ SYNC_DESTINATIONS=*)
-            destinations_ref=("${SYNC_DESTINATIONS[@]}")
-            ;;
-        *)
-            if [ -n "${SYNC_DESTINATIONS:-}" ]; then
-                # shellcheck disable=SC2034
-                read -r -a destinations_ref <<< "$SYNC_DESTINATIONS"
-            fi
-            ;;
-    esac
-}
-
 # Inlined from src/lib/template.source.sh
 _html_escape() {
     local -r text="$1"; shift
@@ -1017,89 +996,7 @@ template() {
     fi
 }
 
-# Inlined from src/lib/image.source.sh
-cleanphotos() {
-    local basename
-    local photo
-    local sub
-
-    while IFS= read -r photo; do
-        basename=$(basename "$photo")
-
-        if [[ -f "$INCOMING_DIR/$basename" ]] \
-            && is_supported_image_file "$basename"; then
-            continue
-        fi
-
-        log_info "Cleaning up $(_display_path "$photo")"
-        for sub in thumbs blurs photos; do
-            if [ -f "$DIST_DIR/$sub/$basename" ]; then
-                rm -f "$DIST_DIR/$sub/$basename"
-                log_info "removed '$(_display_path "$DIST_DIR/$sub/$basename")'"
-            fi
-        done
-    done < <(find "$DIST_DIR/photos" -maxdepth 1 -type f)
-}
-
-is_supported_image_file() {
-    local -r file="$1"; shift
-    local extension
-
-    if [[ "$file" != *.* ]]; then
-        return 1
-    fi
-
-    extension="${file##*.}"
-    extension="${extension,,}"
-
-    case "$extension" in
-        gif|jpeg|jpg|png|webp)
-            return 0
-            ;;
-        *)
-            return 1
-            ;;
-    esac
-}
-
-incoming_image_files() {
-    local file
-
-    while IFS= read -r file; do
-        if is_supported_image_file "$file"; then
-            printf '%s\n' "$file"
-        fi
-    done < <(find "$INCOMING_DIR" -maxdepth 1 -type f -printf '%f\n') \
-        | sort
-}
-
-warn_unsupported_incoming_files() {
-    local file
-
-    while IFS= read -r file; do
-        if ! is_supported_image_file "$file"; then
-            log_warning "Ignoring unsupported incoming file: $file"
-        fi
-    done < <(find "$INCOMING_DIR" -maxdepth 1 -type f -printf '%f\n' | sort)
-}
-
-scalephotos() {
-    local -i failed=0
-    local -a image_job_pids=()
-    local photo
-
-    while IFS= read -r photo; do
-        wait_for_image_job_slot image_job_pids failed
-        scale_photo "$photo" &
-        image_job_pids+=("$!")
-    done < <(incoming_image_files)
-
-    wait_for_image_jobs image_job_pids failed
-    if (( failed != 0 )); then
-        return 1
-    fi
-}
-
+# Inlined from src/lib/job-pool.source.sh
 wait_for_parallel_job_pid() {
     local -r pid="$1"; shift
     local -i status=0
@@ -1238,6 +1135,89 @@ wait_for_template_render_jobs() {
     wait_for_parallel_jobs "$render_job_pids_name" "$failed_name"
 }
 
+# Inlined from src/lib/image.source.sh
+cleanphotos() {
+    local basename
+    local photo
+    local sub
+
+    while IFS= read -r photo; do
+        basename=$(basename "$photo")
+
+        if [[ -f "$INCOMING_DIR/$basename" ]] \
+            && is_supported_image_file "$basename"; then
+            continue
+        fi
+
+        log_info "Cleaning up $(_display_path "$photo")"
+        for sub in thumbs blurs photos; do
+            if [ -f "$DIST_DIR/$sub/$basename" ]; then
+                rm -f "$DIST_DIR/$sub/$basename"
+                log_info "removed '$(_display_path "$DIST_DIR/$sub/$basename")'"
+            fi
+        done
+    done < <(find "$DIST_DIR/photos" -maxdepth 1 -type f)
+}
+
+is_supported_image_file() {
+    local -r file="$1"; shift
+    local extension
+
+    if [[ "$file" != *.* ]]; then
+        return 1
+    fi
+
+    extension="${file##*.}"
+    extension="${extension,,}"
+
+    case "$extension" in
+        gif|jpeg|jpg|png|webp)
+            return 0
+            ;;
+        *)
+            return 1
+            ;;
+    esac
+}
+
+incoming_image_files() {
+    local file
+
+    while IFS= read -r file; do
+        if is_supported_image_file "$file"; then
+            printf '%s\n' "$file"
+        fi
+    done < <(find "$INCOMING_DIR" -maxdepth 1 -type f -printf '%f\n') \
+        | sort
+}
+
+warn_unsupported_incoming_files() {
+    local file
+
+    while IFS= read -r file; do
+        if ! is_supported_image_file "$file"; then
+            log_warning "Ignoring unsupported incoming file: $file"
+        fi
+    done < <(find "$INCOMING_DIR" -maxdepth 1 -type f -printf '%f\n' | sort)
+}
+
+scalephotos() {
+    local -i failed=0
+    local -a image_job_pids=()
+    local photo
+
+    while IFS= read -r photo; do
+        wait_for_image_job_slot image_job_pids failed
+        scale_photo "$photo" &
+        image_job_pids+=("$!")
+    done < <(incoming_image_files)
+
+    wait_for_image_jobs image_job_pids failed
+    if (( failed != 0 )); then
+        return 1
+    fi
+}
+
 scale_photo() {
     local -r photo="$1"; shift
     local destphoto
@@ -1269,6 +1249,7 @@ scale_photo() {
     fi
 }
 
+# Inlined from src/lib/random.source.sh
 random_seed_is_set() {
     [ -n "$RANDOM_SEED" ]
 }
@@ -2625,6 +2606,29 @@ print_config() {
 }
 
 # Inlined from src/lib/config.sync.source.sh
+resolve_sync_destinations() {
+    local -n destinations_ref="$1"; shift
+    local destinations_decl
+
+    destinations_ref=()
+
+    if ! destinations_decl=$(declare -p SYNC_DESTINATIONS 2>/dev/null); then
+        return
+    fi
+
+    case "$destinations_decl" in
+        declare\ -a*\ SYNC_DESTINATIONS=*)
+            destinations_ref=("${SYNC_DESTINATIONS[@]}")
+            ;;
+        *)
+            if [ -n "${SYNC_DESTINATIONS:-}" ]; then
+                # shellcheck disable=SC2034
+                read -r -a destinations_ref <<< "$SYNC_DESTINATIONS"
+            fi
+            ;;
+    esac
+}
+
 sync_dist() {
     local destination
     local -a rsync_args=(-av)
diff --git a/src/lib/archive.source.sh b/src/lib/archive.source.sh
new file mode 100644
index 0000000..127a0c5
--- /dev/null
+++ b/src/lib/archive.source.sh
@@ -0,0 +1,52 @@
+tarball() {
+    local -r tarball_name="$1"; shift
+    local -r tarball_suffix="$TARBALL_SUFFIX"
+    local base
+    local old_tarball
+    local -a tar_opts=()
+
+    # Cleanup tarballs from previous runs for the configured suffix.
+    while IFS= read -r -d '' old_tarball; do
+        if [[ "$old_tarball" == *"$tarball_suffix" ]]; then
+            rm -f "$old_tarball"
+        fi
+    done < <(find "$DIST_DIR" -maxdepth 1 -type f -print0)
+
+    base=$(basename "$INCOMING_DIR")
+    resolve_tar_opts tar_opts
+
+    log_info "Creating tarball $(_display_path "$DIST_DIR/$tarball_name")" \
+        "from $INCOMING_DIR"
+    (
+        cd "$(dirname "$INCOMING_DIR")"
+        run_with_timeout tar "$TAR_TIMEOUT" \
+            tar "${tar_opts[@]}" -f "$DIST_DIR/$tarball_name" "$base"
+    )
+}
+
+resolve_tar_opts() {
+    local -n options_ref="$1"; shift
+    local tar_opts_decl
+
+    options_ref=()
+
+    if ! tar_opts_decl=$(declare -p TAR_OPTS 2>/dev/null); then
+        options_ref=(-c)
+        return
+    fi
+
+    case "$tar_opts_decl" in
+        declare\ -a*\ TAR_OPTS=*)
+            options_ref=("${TAR_OPTS[@]}")
+            ;;
+        *)
+            if [ -n "${TAR_OPTS:-}" ]; then
+                read -r -a options_ref <<< "$TAR_OPTS"
+            fi
+            ;;
+    esac
+
+    if (( ${#options_ref[@]} == 0 )); then
+        options_ref=(-c)
+    fi
+}
diff --git a/src/lib/config.sync.source.sh b/src/lib/config.sync.source.sh
index b9362ac..68bb759 100644
--- a/src/lib/config.sync.source.sh
+++ b/src/lib/config.sync.source.sh
@@ -1,3 +1,26 @@
+resolve_sync_destinations() {
+    local -n destinations_ref="$1"; shift
+    local destinations_decl
+
+    destinations_ref=()
+
+    if ! destinations_decl=$(declare -p SYNC_DESTINATIONS 2>/dev/null); then
+        return
+    fi
+
+    case "$destinations_decl" in
+        declare\ -a*\ SYNC_DESTINATIONS=*)
+            destinations_ref=("${SYNC_DESTINATIONS[@]}")
+            ;;
+        *)
+            if [ -n "${SYNC_DESTINATIONS:-}" ]; then
+                # shellcheck disable=SC2034
+                read -r -a destinations_ref <<< "$SYNC_DESTINATIONS"
+            fi
+            ;;
+    esac
+}
+
 sync_dist() {
     local destination
     local -a rsync_args=(-av)
diff --git a/src/lib/image.source.sh b/src/lib/image.source.sh
index 568ab62..c190b87 100644
--- a/src/lib/image.source.sh
+++ b/src/lib/image.source.sh
@@ -80,144 +80,6 @@ scalephotos() {
     fi
 }
 
-wait_for_parallel_job_pid() {
-    local -r pid="$1"; shift
-    local -i status=0
-
-    set +e
-    wait "$pid"
-    status=$?
-    set -e
-
-    return "$status"
-}
-
-parallel_job_pid_is_running() {
-    local -r pid="$1"; shift
-    local running_pid
-
-    for running_pid in "$@"; do
-        if [ "$running_pid" = "$pid" ]; then
-            return 0
-        fi
-    done
-
-    return 1
-}
-
-reap_finished_parallel_jobs() {
-    local -r job_pids_name="$1"; shift
-    # shellcheck disable=SC2178
-    local -n job_pids_ref="$job_pids_name"
-    local -n failed_ref="$1"; shift
-    local -i reaped_status="$1"; shift
-    local -i has_reaped_status=1
-    local -i status=0
-    local -a remaining_pids=()
-    local -a running_pids=()
-    local pid
-
-    mapfile -t running_pids < <(jobs -rp)
-
-    for pid in "${job_pids_ref[@]}"; do
-        if parallel_job_pid_is_running "$pid" "${running_pids[@]}"; then
-            remaining_pids+=("$pid")
-            continue
-        fi
-
-        if wait_for_parallel_job_pid "$pid"; then
-            status=0
-        else
-            status=$?
-        fi
-        if (( status == 127 && has_reaped_status != 0 )); then
-            status=$reaped_status
-            has_reaped_status=0
-        fi
-
-        if (( status != 0 )); then
-            failed_ref=1
-        fi
-    done
-
-    job_pids_ref=("${remaining_pids[@]}")
-}
-
-wait_for_next_parallel_job() {
-    local -r job_pids_name="$1"; shift
-    local -r failed_name="$1"; shift
-    # shellcheck disable=SC2178
-    local -n job_pids_ref="$job_pids_name"
-    local -i status=0
-
-    set +e
-    wait -n "${job_pids_ref[@]}"
-    status=$?
-    set -e
-
-    reap_finished_parallel_jobs "$job_pids_name" "$failed_name" "$status"
-}
-
-wait_for_parallel_job_slot() {
-    local -r job_pids_name="$1"; shift
-    local -r failed_name="$1"; shift
-    local -r max_jobs="$1"; shift
-    # shellcheck disable=SC2178
-    local -n job_pids_ref="$job_pids_name"
-
-    while (( ${#job_pids_ref[@]} >= max_jobs )); do
-        wait_for_next_parallel_job "$job_pids_name" "$failed_name"
-    done
-}
-
-wait_for_parallel_jobs() {
-    # shellcheck disable=SC2178
-    local -n job_pids_ref="$1"; shift
-    local -n failed_ref="$1"; shift
-
-    : "$failed_ref"
-    while (( ${#job_pids_ref[@]} > 0 )); do
-        if ! wait_for_parallel_job_pid "${job_pids_ref[0]}"; then
-            failed_ref=1
-        fi
-        job_pids_ref=("${job_pids_ref[@]:1}")
-    done
-}
-
-wait_for_image_job_slot() {
-    local -r image_job_pids_name="$1"; shift
-    local -r failed_name="$1"; shift
-
-    wait_for_parallel_job_slot \
-        "$image_job_pids_name" \
-        "$failed_name" \
-        "$IMAGE_JOBS"
-}
-
-wait_for_image_jobs() {
-    local -r image_job_pids_name="$1"; shift
-    local -r failed_name="$1"; shift
-
-    wait_for_parallel_jobs "$image_job_pids_name" "$failed_name"
-}
-
-wait_for_template_render_job_slot() {
-    local -r render_job_pids_name="$1"; shift
-    local -r failed_name="$1"; shift
-
-    wait_for_parallel_job_slot \
-        "$render_job_pids_name" \
-        "$failed_name" \
-        "$IMAGE_JOBS"
-}
-
-wait_for_template_render_jobs() {
-    local -r render_job_pids_name="$1"; shift
-    local -r failed_name="$1"; shift
-
-    wait_for_parallel_jobs "$render_job_pids_name" "$failed_name"
-}
-
 scale_photo() {
     local -r photo="$1"; shift
     local destphoto
@@ -248,78 +110,3 @@ scale_photo() {
             "$destphoto"
     fi
 }
-
-random_seed_is_set() {
-    [ -n "$RANDOM_SEED" ]
-}
-
-deterministic_index() {
-    local -r namespace="$1"; shift
-    local -r count="$1"; shift
-    local checksum
-
-    checksum=$(printf '%s' "${RANDOM_SEED}:$namespace" | cksum)
-    checksum=${checksum%% *}
-
-    printf '%s\n' $(( checksum % count ))
-}
-
-random_index() {
-    local -r namespace="$1"; shift
-    local -r count="$1"; shift
-
-    if random_seed_is_set; then
-        deterministic_index "$namespace" "$count"
-    else
-        printf '%s\n' $(( RANDOM % count ))
-    fi
-}
-
-random_animation_css_class() {
-    local -r speed="$1"; shift
-    local -r context="${1:-$speed}"
-    local -i index
-    local -a classes=(
-        "animate-opacity-$speed"
-        "animate-top-$speed"
-        "animate-left-$speed"
-        "animate-right-$speed"
-        "animate-bottom-$speed"
-        "animate-zoom-$speed"
-        "animate-snap-rotate-$speed"
-        "animate-hard-zoom-$speed"
-        "animate-slam-left-$speed"
-        "animate-slam-right-$speed"
-        "animate-flash-in-$speed"
-        "animate-invert-pop-$speed"
-        "animate-posterize-pop-$speed"
-        "animate-skew-snap-$speed"
-        "animate-glitch-step-$speed"
-    )
-
-    index=$(random_index "animation:$speed:$context" "${#classes[@]}")
-    printf '%s\n' "${classes[index]}"
-}
-
-deterministic_shuffle() {
-    local checksum
-    local line
-
-    while IFS= read -r line; do
-        checksum=$(printf '%s' "${RANDOM_SEED}:shuffle:$line" | cksum)
-        checksum=${checksum%% *}
-        printf '%010u\t%s\n' "$checksum" "$line"
-    done | sort -n -k1,1 -k2,2 | cut -f2-
-}
-
-maybe_shuffle() {
-    if [ "$SHUFFLE" = yes ]; then
-        if random_seed_is_set; then
-            deterministic_shuffle
-        else
-            sort -R
-        fi
-    else
-        sort
-    fi
-}
diff --git a/src/lib/imagemagick.source.sh b/src/lib/imagemagick.source.sh
new file mode 100644
index 0000000..cdc909c
--- /dev/null
+++ b/src/lib/imagemagick.source.sh
@@ -0,0 +1,71 @@
+# shellcheck disable=SC2034
+resolve_imagemagick_command() {
+    local -r operation="$1"; shift
+    local -n command_ref="$1"; shift
+
+    command_ref=()
+
+    case "$operation" in
+        convert)
+            if command -v magick >/dev/null 2>&1; then
+                command_ref=(magick)
+                return
+            fi
+            if command -v convert >/dev/null 2>&1; then
+                command_ref=(convert)
+                return
+            fi
+            ;;
+        identify)
+            if command -v magick >/dev/null 2>&1; then
+                command_ref=(magick identify)
+                return
+            fi
+            if command -v identify >/dev/null 2>&1; then
+                command_ref=(identify)
+                return
+            fi
+            if command -v convert >/dev/null 2>&1; then
+                command_ref=(convert)
+                return
+            fi
+            ;;
+        *)
+            printf 'ERROR: Unknown ImageMagick operation %s\n' \
+                "$operation" >&2
+            return 1
+            ;;
+    esac
+
+    printf 'ERROR: ImageMagick is required; install magick or convert\n' >&2
+    return 127
+}
+
+imagemagick() {
+    local -a imagemagick_command=()
+
+    resolve_imagemagick_command convert imagemagick_command || return
+
+    run_with_timeout ImageMagick "$IMAGEMAGICK_TIMEOUT" \
+        "${imagemagick_command[@]}" "$@"
+}
+
+imagemagick_identify() {
+    local -a imagemagick_command=()
+
+    resolve_imagemagick_command identify imagemagick_command || return
+
+    if [ "${imagemagick_command[0]}" = convert ]; then
+        if [[ "${1:-}" = '-verbose' && $# -eq 2 ]]; then
+            run_with_timeout ImageMagick "$IMAGEMAGICK_TIMEOUT" \
+                "${imagemagick_command[@]}" "$2" -verbose info:
+        else
+            run_with_timeout ImageMagick "$IMAGEMAGICK_TIMEOUT" \
+                "${imagemagick_command[@]}" "$@" info:
+        fi
+        return
+    fi
+
+    run_with_timeout ImageMagick "$IMAGEMAGICK_TIMEOUT" \
+        "${imagemagick_command[@]}" "$@"
+}
diff --git a/src/lib/job-pool.source.sh b/src/lib/job-pool.source.sh
new file mode 100644
index 0000000..5c629aa
--- /dev/null
+++ b/src/lib/job-pool.source.sh
@@ -0,0 +1,137 @@
+wait_for_parallel_job_pid() {
+    local -r pid="$1"; shift
+    local -i status=0
+
+    set +e
+    wait "$pid"
+    status=$?
+    set -e
+
+    return "$status"
+}
+
+parallel_job_pid_is_running() {
+    local -r pid="$1"; shift
+    local running_pid
+
+    for running_pid in "$@"; do
+        if [ "$running_pid" = "$pid" ]; then
+            return 0
+        fi
+    done
+
+    return 1
+}
+
+reap_finished_parallel_jobs() {
+    local -r job_pids_name="$1"; shift
+    # shellcheck disable=SC2178
+    local -n job_pids_ref="$job_pids_name"
+    local -n failed_ref="$1"; shift
+    local -i reaped_status="$1"; shift
+    local -i has_reaped_status=1
+    local -i status=0
+    local -a remaining_pids=()
+    local -a running_pids=()
+    local pid
+
+    mapfile -t running_pids < <(jobs -rp)
+
+    for pid in "${job_pids_ref[@]}"; do
+        if parallel_job_pid_is_running "$pid" "${running_pids[@]}"; then
+            remaining_pids+=("$pid")
+            continue
+        fi
+
+        if wait_for_parallel_job_pid "$pid"; then
+            status=0
+        else
+            status=$?
+        fi
+        if (( status == 127 && has_reaped_status != 0 )); then
+            status=$reaped_status
+            has_reaped_status=0
+        fi
+
+        if (( status != 0 )); then
+            failed_ref=1
+        fi
+    done
+
+    job_pids_ref=("${remaining_pids[@]}")
+}
+
+wait_for_next_parallel_job() {
+    local -r job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+    # shellcheck disable=SC2178
+    local -n job_pids_ref="$job_pids_name"
+    local -i status=0
+
+    set +e
+    wait -n "${job_pids_ref[@]}"
+    status=$?
+    set -e
+
+    reap_finished_parallel_jobs "$job_pids_name" "$failed_name" "$status"
+}
+
+wait_for_parallel_job_slot() {
+    local -r job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+    local -r max_jobs="$1"; shift
+    # shellcheck disable=SC2178
+    local -n job_pids_ref="$job_pids_name"
+
+    while (( ${#job_pids_ref[@]} >= max_jobs )); do
+        wait_for_next_parallel_job "$job_pids_name" "$failed_name"
+    done
+}
+
+wait_for_parallel_jobs() {
+    # shellcheck disable=SC2178
+    local -n job_pids_ref="$1"; shift
+    local -n failed_ref="$1"; shift
+
+    : "$failed_ref"
+    while (( ${#job_pids_ref[@]} > 0 )); do
+        if ! wait_for_parallel_job_pid "${job_pids_ref[0]}"; then
+            failed_ref=1
+        fi
+        job_pids_ref=("${job_pids_ref[@]:1}")
+    done
+}
+
+wait_for_image_job_slot() {
+    local -r image_job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+
+    wait_for_parallel_job_slot \
+        "$image_job_pids_name" \
+        "$failed_name" \
+        "$IMAGE_JOBS"
+}
+
+wait_for_image_jobs() {
+    local -r image_job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+
+    wait_for_parallel_jobs "$image_job_pids_name" "$failed_name"
+}
+
+wait_for_template_render_job_slot() {
+    local -r render_job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+
+    wait_for_parallel_job_slot \
+        "$render_job_pids_name" \
+        "$failed_name" \
+        "$IMAGE_JOBS"
+}
+
+wait_for_template_render_jobs() {
+    local -r render_job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+
+    wait_for_parallel_jobs "$render_job_pids_name" "$failed_name"
+}
diff --git a/src/lib/process.source.sh b/src/lib/process.source.sh
new file mode 100644
index 0000000..5596e03
--- /dev/null
+++ b/src/lib/process.source.sh
@@ -0,0 +1,24 @@
+run_with_timeout() {
+    local -r description="$1"; shift
+    local -r seconds="$1"; shift
+    local -i status=0
+
+    if ! command -v timeout >/dev/null 2>&1; then
+        printf 'ERROR: timeout command is required to run %s\n' \
+            "$description" >&2
+        return 127
+    fi
+
+    if timeout "$seconds" "$@"; then
+        return
+    else
+        status=$?
+    fi
+
+    if (( status == 124 )); then
+        printf 'ERROR: %s timed out after %s seconds\n' \
+            "$description" "$seconds" >&2
+    fi
+
+    return "$status"
+}
diff --git a/src/lib/random.source.sh b/src/lib/random.source.sh
new file mode 100644
index 0000000..5a1ef59
--- /dev/null
+++ b/src/lib/random.source.sh
@@ -0,0 +1,74 @@
+random_seed_is_set() {
+    [ -n "$RANDOM_SEED" ]
+}
+
+deterministic_index() {
+    local -r namespace="$1"; shift
+    local -r count="$1"; shift
+    local checksum
+
+    checksum=$(printf '%s' "${RANDOM_SEED}:$namespace" | cksum)
+    checksum=${checksum%% *}
+
+    printf '%s\n' $(( checksum % count ))
+}
+
+random_index() {
+    local -r namespace="$1"; shift
+    local -r count="$1"; shift
+
+    if random_seed_is_set; then
+        deterministic_index "$namespace" "$count"
+    else
+        printf '%s\n' $(( RANDOM % count ))
+    fi
+}
+
+random_animation_css_class() {
+    local -r speed="$1"; shift
+    local -r context="${1:-$speed}"
+    local -i index
+    local -a classes=(
+        "animate-opacity-$speed"
+        "animate-top-$speed"
+        "animate-left-$speed"
+        "animate-right-$speed"
+        "animate-bottom-$speed"
+        "animate-zoom-$speed"
+        "animate-snap-rotate-$speed"
+        "animate-hard-zoom-$speed"
+        "animate-slam-left-$speed"
+        "animate-slam-right-$speed"
+        "animate-flash-in-$speed"
+        "animate-invert-pop-$speed"
+        "animate-posterize-pop-$speed"
+        "animate-skew-snap-$speed"
+        "animate-glitch-step-$speed"
+    )
+
+    index=$(random_index "animation:$speed:$context" "${#classes[@]}")
+    printf '%s\n' "${classes[index]}"
+}
+
+deterministic_shuffle() {
+    local checksum
+    local line
+
+    while IFS= read -r line; do
+        checksum=$(printf '%s' "${RANDOM_SEED}:shuffle:$line" | cksum)
+        checksum=${checksum%% *}
+        printf '%010u\t%s\n' "$checksum" "$line"
+    done | sort -n -k1,1 -k2,2 | cut -f2-
+}
+
+maybe_shuffle() {
+    if [ "$SHUFFLE" = yes ]; then
+        if random_seed_is_set; then
+            deterministic_shuffle
+        else
+            sort -R
+        fi
+    else
+        sort
+    fi
+}
diff --git a/src/lib/system.source.sh b/src/lib/system.source.sh
deleted file mode 100644
index 5d6f8e7..0000000
--- a/src/lib/system.source.sh
+++ /dev/null
@@ -1,172 +0,0 @@
-# shellcheck disable=SC2034
-resolve_imagemagick_command() {
-    local -r operation="$1"; shift
-    local -n command_ref="$1"; shift
-
-    command_ref=()
-
-    case "$operation" in
-        convert)
-            if command -v magick >/dev/null 2>&1; then
-                command_ref=(magick)
-                return
-            fi
-            if command -v convert >/dev/null 2>&1; then
-                command_ref=(convert)
-                return
-            fi
-            ;;
-        identify)
-            if command -v magick >/dev/null 2>&1; then
-                command_ref=(magick identify)
-                return
-            fi
-            if command -v identify >/dev/null 2>&1; then
-                command_ref=(identify)
-                return
-            fi
-            if command -v convert >/dev/null 2>&1; then
-                command_ref=(convert)
-                return
-            fi
-            ;;
-        *)
-            printf 'ERROR: Unknown ImageMagick operation %s\n' \
-                "$operation" >&2
-            return 1
-            ;;
-    esac
-
-    printf 'ERROR: ImageMagick is required; install magick or convert\n' >&2
-    return 127
-}
-
-imagemagick() {
-    local -a imagemagick_command=()
-
-    resolve_imagemagick_command convert imagemagick_command || return
-
-    run_with_timeout ImageMagick "$IMAGEMAGICK_TIMEOUT" \
-        "${imagemagick_command[@]}" "$@"
-}
-
-imagemagick_identify() {
-    local -a imagemagick_command=()
-
-    resolve_imagemagick_command identify imagemagick_command || return
-
-    if [ "${imagemagick_command[0]}" = convert ]; then
-        if [[ "${1:-}" = '-verbose' && $# -eq 2 ]]; then
-            run_with_timeout ImageMagick "$IMAGEMAGICK_TIMEOUT" \
-                "${imagemagick_command[@]}" "$2" -verbose info:
-        else
-            run_with_timeout ImageMagick "$IMAGEMAGICK_TIMEOUT" \
-                "${imagemagick_command[@]}" "$@" info:
-        fi
-        return
-    fi
-
-    run_with_timeout ImageMagick "$IMAGEMAGICK_TIMEOUT" \
-        "${imagemagick_command[@]}" "$@"
-}
-
-run_with_timeout() {
-    local -r description="$1"; shift
-    local -r seconds="$1"; shift
-    local -i status=0
-
-    if ! command -v timeout >/dev/null 2>&1; then
-        printf 'ERROR: timeout command is required to run %s\n' \
-            "$description" >&2
-        return 127
-    fi
-
-    if timeout "$seconds" "$@"; then
-        return
-    else
-        status=$?
-    fi
-
-    if (( status == 124 )); then
-        printf 'ERROR: %s timed out after %s seconds\n' \
-            "$description" "$seconds" >&2
-    fi
-
-    return "$status"
-}
-
-tarball() {
-    local -r tarball_name="$1"; shift
-    local -r tarball_suffix="$TARBALL_SUFFIX"
-    local base
-    local old_tarball
-    local -a tar_opts=()
-
-    # Cleanup tarballs from previous runs for the configured suffix.
-    while IFS= read -r -d '' old_tarball; do
-        if [[ "$old_tarball" == *"$tarball_suffix" ]]; then
-            rm -f "$old_tarball"
-        fi
-    done < <(find "$DIST_DIR" -maxdepth 1 -type f -print0)
-
-    base=$(basename "$INCOMING_DIR")
-    resolve_tar_opts tar_opts
-
-    log_info "Creating tarball $(_display_path "$DIST_DIR/$tarball_name")" \
-        "from $INCOMING_DIR"
-    (
-        cd "$(dirname "$INCOMING_DIR")"
-        run_with_timeout tar "$TAR_TIMEOUT" \
-            tar "${tar_opts[@]}" -f "$DIST_DIR/$tarball_name" "$base"
-    )
-}
-
-resolve_tar_opts() {
-    local -n options_ref="$1"; shift
-    local tar_opts_decl
-
-    options_ref=()
-
-    if ! tar_opts_decl=$(declare -p TAR_OPTS 2>/dev/null); then
-        options_ref=(-c)
-        return
-    fi
-
-    case "$tar_opts_decl" in
-        declare\ -a*\ TAR_OPTS=*)
-            options_ref=("${TAR_OPTS[@]}")
-            ;;
-        *)
-            if [ -n "${TAR_OPTS:-}" ]; then
-                read -r -a options_ref <<< "$TAR_OPTS"
-            fi
-            ;;
-    esac
-
-    if (( ${#options_ref[@]} == 0 )); then
-        options_ref=(-c)
-    fi
-}
-
-resolve_sync_destinations() {
-    local -n destinations_ref="$1"; shift
-    local destinations_decl
-
-    destinations_ref=()
-
-    if ! destinations_decl=$(declare -p SYNC_DESTINATIONS 2>/dev/null); then
-        return
-    fi
-
-    case "$destinations_decl" in
-        declare\ -a*\ SYNC_DESTINATIONS=*)
-            destinations_ref=("${SYNC_DESTINATIONS[@]}")
-            ;;
-        *)
-            if [ -n "${SYNC_DESTINATIONS:-}" ]; then
-                # shellcheck disable=SC2034
-                read -r -a destinations_ref <<< "$SYNC_DESTINATIONS"
-            fi
-            ;;
-    esac
-}
diff --git a/src/shuriken.sh b/src/