#!/usr/bin/env bash
# Install the Rust collector (rust/collector, `ping-collector`) and switch
# data collection over to it, or back.
#
#   sudo bash scripts/install_collector.sh             # install binary + unit, dry-run check
#   sudo bash scripts/install_collector.sh --cutover   # install, then Rust collects:
#                                                      #   COLLECTION_ENABLED=false, start
#                                                      #   ping-collector, restart water-monitor
#   sudo bash scripts/install_collector.sh --rollback  # Python collects again
#
# The binary comes from BIN=/path/to/ping-collector (e.g. the "ping-collector-
# linux-x86_64" CI artifact) or from rust/target/release/ping-collector, built
# beforehand as a normal user:
#   cargo build --release --locked --manifest-path rust/Cargo.toml
# (needs rustup, pkg-config and libssl-dev).
set -euo pipefail

APP_DIR="${APP_DIR:-/opt/thailand-water-monitor}"
ENV_FILE="${APP_DIR}/.env"
STATUS_FILE="${APP_DIR}/collector-status.json"
REPO_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
MODE="${1:-install}"

log() { printf '\033[1;32m==>\033[0m %s\n' "$*"; }
die() { printf '\033[1;31m[error]\033[0m %s\n' "$*" >&2; exit 1; }

[ "$(id -u)" -eq 0 ] || die "run as root (sudo)"
[ -f "$ENV_FILE" ] || die "$ENV_FILE not found"

set_env() {
    local key="$1" value="$2"
    if grep -q "^${key}=" "$ENV_FILE"; then
        sed -i "s|^${key}=.*|${key}=${value}|" "$ENV_FILE"
    else
        printf '%s=%s\n' "$key" "$value" >>"$ENV_FILE"
    fi
}

if [ "$MODE" = "--rollback" ]; then
    log "Stopping ping-collector; the Python app collects again"
    systemctl disable --now ping-collector.service 2>/dev/null || true
    set_env COLLECTION_ENABLED true
    systemctl restart water-monitor.service
    log "Done. Check: journalctl -u water-monitor -n 50"
    exit 0
fi
case "$MODE" in install | --cutover) ;; *) die "unknown option: $MODE" ;; esac

BIN="${BIN:-${REPO_DIR}/rust/target/release/ping-collector}"
[ -x "$BIN" ] || die "no binary at $BIN: build it (see header) or pass BIN=/path/to/ping-collector"

log "Installing $BIN -> ${APP_DIR}/bin/ping-collector ($("$BIN" --version))"
install -D -m 0755 -o root -g root "$BIN" "${APP_DIR}/bin/ping-collector"
install -m 0644 "${REPO_DIR}/scripts/ping-collector.service" /etc/systemd/system/ping-collector.service
systemctl daemon-reload

# Both services read and write /scraping/status through this file (inside
# the app dir: the units use PrivateTmp).
set_env SCRAPING_STATUS_FILE "$STATUS_FILE"
touch "$STATUS_FILE"
chown "$(stat -c %U:%G "$APP_DIR")" "$STATUS_FILE"

log "Dry run against the configured database (writes nothing)"
(cd "$APP_DIR" && "${APP_DIR}/bin/ping-collector" --env-file "$ENV_FILE" once --dry-run)

if [ "$MODE" = "--cutover" ]; then
    log "Cutover: ping-collector collects, the Python app forecasts and notifies"
    set_env COLLECTION_ENABLED false
    systemctl enable --now ping-collector.service
    systemctl restart water-monitor.service
    sleep 20
    systemctl --no-pager --lines=0 status ping-collector.service || true
    journalctl -u ping-collector -n 20 --no-pager || true
    log "Rollback if needed: sudo bash scripts/install_collector.sh --rollback"
else
    log "Installed, not started. Switch over with: sudo bash scripts/install_collector.sh --cutover"
fi