#!/usr/bin/env bash
# Run on the Proxmox host when build_cloudinit_request.json appears in the provisioning dir.
# Downloads Raspberry Pi OS image from URL, injects cloud-init NoCloud files, saves to BACKUPS_DIR.
# Uses loop devices and mount (available on host, not in unprivileged LXC).
# Triggered by systemd path unit cm4-build-cloudinit.path.

set -e
PROV_DIR="${CM4_PROVISIONING_DIR:-/var/lib/cm4-provisioning}"
REQUEST_FILE="$PROV_DIR/build_cloudinit_request.json"
STATUS_FILE="$PROV_DIR/build_cloudinit_status.json"
[[ -f /opt/cm4-provisioning/env ]] && source /opt/cm4-provisioning/env
BACKUPS_DIR="${BACKUPS_DIR:-$PROV_DIR/backups}"
CLOUDINIT_IMAGES_DIR="${CLOUDINIT_IMAGES_DIR:-$PROV_DIR/cloudinit-images}"
# Write built cloud-init images to CLOUDINIT_IMAGES_DIR (separate from backups)
OUTPUT_DIR="${CLOUDINIT_IMAGES_DIR}"
GOLDEN_IMAGE="${GOLDEN_IMAGE:-$PROV_DIR/golden.img}"

write_status() {
    local phase="$1" message="$2" output_name="$3" error="$4"
    printf '{"phase":"%s","message":"%s","output_name":%s,"error":%s,"updated":%s}\n' \
        "$phase" "$message" \
        "$([ -n "$output_name" ] && echo "\"$output_name\"" || echo "null")" \
        "$([ -n "$error" ] && echo "\"${error//\"/\\\"}\"" || echo "null")" \
        "$(date +%s)" > "$STATUS_FILE"
}

[[ -f "$REQUEST_FILE" ]] || { echo "No request file"; exit 0; }

TEMP_DIR=$(mktemp -d)
trap 'rm -rf "$TEMP_DIR"; rm -f "$REQUEST_FILE"' EXIT

# Extract fields from JSON into temp files (handles multi-line content)
python3 - "$REQUEST_FILE" "$TEMP_DIR" << 'PY'
import json, sys
with open(sys.argv[1]) as f:
    d = json.load(f)
out = sys.argv[2]
for name, key in [("user-data", "user_data"), ("meta-data", "meta_data"), ("network-config", "network_config")]:
    with open(f"{out}/{name}", "w") as f:
        f.write(d.get(key, ""))
with open(f"{out}/variant", "w") as f:
    f.write(d.get("variant", "lite"))
with open(f"{out}/url", "w") as f:
    f.write(d.get("url", ""))
with open(f"{out}/set_golden", "w") as f:
    f.write("1" if d.get("set_as_golden_after") else "0")
PY

URL=$(cat "$TEMP_DIR/url")
VARIANT=$(cat "$TEMP_DIR/variant")
SET_AS_GOLDEN=$(cat "$TEMP_DIR/set_golden")
[[ -n "$URL" ]] || { write_status "error" "" "" "Missing url in request"; exit 1; }

OUT_NAME="raspios-${VARIANT}-cloudinit-$(date +%Y%m%d-%H%M%S).img"
OUT_PATH="$OUTPUT_DIR/$OUT_NAME"

write_status "downloading" "Downloading $(basename "$URL")…" "" ""
XZ_FILE="$TEMP_DIR/image.img.xz"
CURL_ERR="$TEMP_DIR/curl_err.txt"
CURL_OPTS=(-f -L -o "$XZ_FILE" --connect-timeout 30 --max-time 7200)
[[ "${CURL_INSECURE:-}" == "1" ]] && CURL_OPTS+=(-k)
if ! curl "${CURL_OPTS[@]}" "$URL" 2>"$CURL_ERR"; then
    err_detail=$(head -c 200 "$CURL_ERR" | tr '\n' ' ' | sed 's/"/\\"/g')
    write_status "error" "" "" "Download failed: ${err_detail:-curl exited with error}"
    exit 1
fi

write_status "decompressing" "Decompressing image…" "" ""
# Check we have a real xz file (not HTML error page)
if ! command -v xz >/dev/null 2>&1; then
    write_status "error" "" "" "Decompress failed: xz not installed. Install xz-utils (apt install xz-utils)"
    exit 1
fi
if [[ ! -s "$XZ_FILE" ]]; then
    write_status "error" "" "" "Decompress failed: downloaded file is empty"
    exit 1
fi
FILE_TYPE=$(file -b "$XZ_FILE" 2>/dev/null || true)
if [[ "$FILE_TYPE" == *"HTML"* ]] || [[ "$FILE_TYPE" == *"text"* ]] && [[ "$FILE_TYPE" != *"XZ"* ]]; then
    write_status "error" "" "" "Decompress failed: download is not an image (got: ${FILE_TYPE:0:80})"
    exit 1
fi
IMG_FILE="$TEMP_DIR/image.img"
XZ_ERR="$TEMP_DIR/xz_err.txt"
if ! xz -d -k -f "$XZ_FILE" 2>"$XZ_ERR"; then
    err_detail=$(head -c 300 "$XZ_ERR" 2>/dev/null | tr '\n' ' ' | sed 's/"/\\"/g')
    write_status "error" "" "" "Decompress failed: ${err_detail:-xz exited with error}"
    exit 1
fi
[[ -f "$IMG_FILE" ]] || { write_status "error" "" "" "image.img not found after decompress"; exit 1; }

write_status "injecting" "Mounting boot partition and injecting cloud-init…" "" ""
LOOP=$(losetup -f --show -P "$IMG_FILE")
boot_part="${LOOP}p1"
[[ -b "$boot_part" ]] || boot_part="${LOOP}p2"
[[ -b "$boot_part" ]] || { write_status "error" "" "" "Boot partition not found"; losetup -d "$LOOP"; exit 1; }

MNT="$TEMP_DIR/mnt"
mkdir -p "$MNT"
mount "$boot_part" "$MNT"
cp "$TEMP_DIR/user-data" "$MNT/user-data"
cp "$TEMP_DIR/meta-data" "$MNT/meta-data"
cp "$TEMP_DIR/network-config" "$MNT/network-config"
umount "$MNT"
losetup -d "$LOOP"

write_status "finalizing" "Copying image to cloud-init images…" "" ""
mkdir -p "$OUTPUT_DIR"
cp "$IMG_FILE" "$OUT_PATH"

if [[ "$SET_AS_GOLDEN" == "1" ]]; then
    rm -f "$GOLDEN_IMAGE"
    ln -sf "$OUT_PATH" "$GOLDEN_IMAGE"
    write_status "done" "Built $OUT_NAME and set as golden image." "$OUT_NAME" ""
else
    write_status "done" "Built $OUT_NAME" "$OUT_NAME" ""
fi