#!/usr/bin/env bash
# nanobot deploy/rollback supervisor
# Manages git-checkout-based deployments with health checks and automatic rollback.
#
# Usage:
#   deploy.sh <commit-ish>     Deploy a candidate commit
#   deploy.sh rollback          Rollback to last known-good
#   deploy.sh status            Show current deployment state

set -euo pipefail

CHECKOUT="/home/claw/nanobot-src"
STATE_FILE="/home/claw/.nanobot/deploy-state.json"
HEALTH_URL="http://127.0.0.1:18790/health"
STABILIZE_SEC=8
HEALTH_TIMEOUT_SEC=30
SERVICE="nanobot"

log() { echo "[deploy] $(date '+%H:%M:%S') $*"; }

# ---- helpers ----

current_commit() { git -C "$CHECKOUT" rev-parse HEAD; }
short_hash() { echo "${1:0:8}"; }

read_state() {
    if [[ -f "$STATE_FILE" ]]; then
        python3 -c "import json; d=json.load(open('$STATE_FILE')); print(d.get('known_good',''))"
    else
        echo ""
    fi
}

write_state() {
    local known_good="$1"
    python3 -c "
import json, sys
d = {}
try: d = json.load(open('$STATE_FILE'))
except: pass
d['known_good'] = '$known_good'
d['last_updated'] = '$(date -Iseconds)'
json.dump(d, open('$STATE_FILE', 'w'), indent=2)
"
}

restart_service() {
    export XDG_RUNTIME_DIR=/run/user/1000
    systemctl --user restart "$SERVICE"
}

service_active() {
    export XDG_RUNTIME_DIR=/run/user/1000
    systemctl --user is-active --quiet "$SERVICE"
}

health_check() {
    # Returns 0 if healthy, 1 if not
    local deadline=$((SECONDS + HEALTH_TIMEOUT_SEC))
    while (( SECONDS < deadline )); do
        if curl -sf --max-time 3 "$HEALTH_URL" >/dev/null 2>&1; then
            return 0
        fi
        sleep 1
    done
    return 1
}

# ---- commands ----

cmd_status() {
    echo "Checkout: $CHECKOUT"
    echo "Current commit: $(current_commit) ($(short_hash "$(current_commit)"))"
    echo "Known-good:     $(read_state)"
    echo "Service:        $(service_active && echo 'active' || echo 'inactive')"
}

cmd_deploy() {
    local candidate="$1"
    local known_good
    known_good=$(read_state)

    cd "$CHECKOUT"

    # Record current as known-good if not set
    if [[ -z "$known_good" ]]; then
        known_good=$(current_commit)
        write_state "$known_good"
        log "Initial known-good: $(short_hash "$known_good")"
    fi

    # Check candidate exists
    if ! git cat-file -e "$candidate^{commit}" 2>/dev/null; then
        log "ERROR: candidate '$candidate' is not a valid commit"
        return 1
    fi

    local candidate_hash
    candidate_hash=$(git rev-parse "$candidate")

    if [[ "$candidate_hash" == "$(current_commit)" ]]; then
        log "Already at candidate $(short_hash "$candidate_hash"), just restarting"
    else
        log "Deploying candidate: $(short_hash "$candidate_hash")"
        log "Known-good: $(short_hash "$known_good")"

        git checkout "$candidate_hash"
    fi

    log "Restarting service..."
    restart_service

    log "Waiting ${STABILIZE_SEC}s for stabilization..."
    sleep "$STABILIZE_SEC"

    if ! service_active; then
        log "ERROR: service not active after restart"
        cmd_rollback_internal "$known_good" "$candidate_hash"
        return 1
    fi

    log "Running health check..."
    if health_check; then
        log "Health check PASSED"
        write_state "$candidate_hash"
        log "Promoted $(short_hash "$candidate_hash") to known-good"
    else
        log "ERROR: health check FAILED"
        cmd_rollback_internal "$known_good" "$candidate_hash"
        return 1
    fi
}

cmd_rollback_internal() {
    local target="$1"
    local failed="${2:-unknown}"

    log "ROLLING BACK to $(short_hash "$target")"

    cd "$CHECKOUT"
    git checkout "$target"
    restart_service

    sleep "$STABILIZE_SEC"

    if service_active && health_check; then
        log "Rollback successful, service healthy"
        # Write failure report
        cat > "/home/claw/.nanobot/deploy-failure.json" <<EOF
{
  "failed_candidate": "$failed",
  "known_good": "$target",
  "timestamp": "$(date -Iseconds)",
  "rollback_successful": true
}
EOF
    else
        log "CRITICAL: rollback also failed! Manual intervention required."
        cat > "/home/claw/.nanobot/deploy-failure.json" <<EOF
{
  "failed_candidate": "$failed",
  "known_good": "$target",
  "timestamp": "$(date -Iseconds)",
  "rollback_successful": false
}
EOF
        return 1
    fi
}

cmd_rollback() {
    local known_good
    known_good=$(read_state)
    if [[ -z "$known_good" ]]; then
        log "No known-good recorded, cannot rollback"
        return 1
    fi
    cmd_rollback_internal "$known_good" "$(current_commit)"
}

# ---- main ----

case "${1:-status}" in
    status)   cmd_status ;;
    rollback) cmd_rollback ;;
    *)        cmd_deploy "$1" ;;
esac