#!/usr/bin/env bash
set -e

if [ "$1" == "--help" ] || [ -z "$1" ]; then
    cat <<EOF >&2
SELECT data from 'system.async_loader' table and render .svg graph of load jobs using 'dot' graphviz tool.
USAGE: async_loader_graph CLICKHOUSE_CLIENT CLIENT_OPTIONS
EXAMPLES:
  $ async_loader_graph clickhouse-client > async_loader.svg
EOF
    exit 1
fi

CLICKHOUSE_CLIENT="$@"

(

echo 'digraph {'
echo 'rankdir=LR;'

$CLICKHOUSE_CLIENT --query='select job, job_id, status, is_blocked, is_ready, is_executing, pool, dependencies from system.async_loader FORMAT JSON' \
    | jq -r '
        .data[]
            | { "FgLoad": "box", "BgLoad": "hexagon", "BgStartup": "ellipse" } as $shape
            | { "PENDING": "white", "OK": "lightgreen", "FAILED": "red", "CANCELED": "darkred" } as $fillcolor
            | [ "black", "blue", "orange", "yellow" ] as $color
            | (.job_id | tostring) as $self
            | [
                # Nodes
                $self + " [label=\"" + .job +
                    "\", shape=\"" + $shape[.pool] +
                    "\", style=\"filled\", fillcolor=\"" + $fillcolor[.status] +
                    "\", penwidth=\"3.0\", color=\"" + $color[.is_blocked + .is_ready * 2 + .is_executing * 3] +
                    "\"];",

                # Edges
                (.dependencies[] | ($self + " -> " + (. | tostring) + ";"))
                ]
            | join("\n")
    '

cat <<LEGEND
    subgraph cluster0 {
        label="LEGEND"
        subgraph cluster1 {
            label="POOL"
            FgLoad[shape="box" penwidth="3.0"];
            BgLoad[shape="hexagon" penwidth="3.0"];
            BgStartup[shape="ellipse" penwidth="3.0"];
        }
        subgraph cluster2 {
            label="STATUS"
            PENDING[shape="ellipse" penwidth="3.0" style="filled" fillcolor="white"];
            OK[shape="ellipse" penwidth="3.0" style="filled" fillcolor="lightgreen"];
            FAILED[shape="ellipse" penwidth="3.0" style="filled" fillcolor="red"];
            CANCELED[shape="ellipse" penwidth="3.0" style="filled" fillcolor="darkred"];
        }
        subgraph cluster3 {
            label="STATE"
            is_assigned[shape="ellipse" penwidth="3.0" style="filled" fillcolor="white" color="black"];
            is_blocked[shape="ellipse" penwidth="3.0" style="filled" fillcolor="white" color="blue"];
            is_ready[shape="ellipse" penwidth="3.0" style="filled" fillcolor="white" color="orange"];
            is_executing[shape="ellipse" penwidth="3.0" style="filled" fillcolor="white" color="yellow"];
        }
        FgLoad -> PENDING -> is_assigned [style="invis"]
    }
LEGEND

echo '}' # digraph

) | dot -Tsvg