import React from "react";
import { connect, ConnectedProps } from "react-redux";
import Container from "@material-ui/core/Container";
import { makeStyles } from "@material-ui/core/styles";
import Grid from "@material-ui/core/Grid";
import Typography from "@material-ui/core/Typography";
import Card from "@material-ui/core/Card";
import CardContent from "@material-ui/core/CardContent";
import SyntaxHighlighter from "react-syntax-highlighter";
import syntaxHighlightStyle from "react-syntax-highlighter/dist/esm/styles/hljs/github";
import { getRedisInfoAsync } from "../actions/redisInfoActions";
import { usePolling } from "../hooks";
import { AppState } from "../store";
import { timeAgoUnix } from "../utils";

const useStyles = makeStyles((theme) => ({
  container: {
    paddingTop: theme.spacing(4),
    paddingBottom: theme.spacing(4),
  },
}));

function mapStateToProps(state: AppState) {
  return {
    loading: state.redis.loading,
    redisInfo: state.redis.data,
    redisAddress: state.redis.address,
    redisInfoRaw: state.redis.rawData,
    pollInterval: state.settings.pollInterval,
  };
}

const connector = connect(mapStateToProps, { getRedisInfoAsync });
type Props = ConnectedProps<typeof connector>;

function RedisInfoView(props: Props) {
  const classes = useStyles();
  const { pollInterval, getRedisInfoAsync, redisInfo, redisInfoRaw } = props;

  usePolling(getRedisInfoAsync, pollInterval);

  // Metrics to show
  // - Used Memory
  // - Memory Fragmentation Ratio
  // - Connected Clients
  // - Connected Replicas (slaves)
  // - Persistence (rdb_last_save_time, rdb_changes_since_last_save)
  // - Errors (rejected_connections)

  return (
    <Container maxWidth="lg" className={classes.container}>
      <Grid container spacing={3}>
        <Grid item xs={12}>
          <Typography variant="h5">Redis Info</Typography>
          <Typography variant="subtitle1" color="textSecondary">
            Connected to: {props.redisAddress}
          </Typography>
        </Grid>
        {redisInfo !== null && (
          <>
            <Grid item xs={12}>
              <Typography variant="h6" color="textSecondary">
                Server
              </Typography>
            </Grid>
            <Grid item xs={3}>
              <MetricCard title="Version" content={redisInfo.redis_version} />
            </Grid>
            <Grid item xs={3}>
              <MetricCard
                title="Uptime"
                content={`${redisInfo.uptime_in_days} days`}
              />
            </Grid>
            <Grid item xs={6} />
            <Grid item xs={12}>
              <Typography variant="h6" color="textSecondary">
                Memory
              </Typography>
            </Grid>
            <Grid item xs={3}>
              <MetricCard
                title="Used Memory"
                content={redisInfo.used_memory_human}
              />
            </Grid>
            <Grid item xs={3}>
              <MetricCard
                title="Peak Memory Used"
                content={redisInfo.used_memory_peak_human}
              />
            </Grid>
            <Grid item xs={3}>
              <MetricCard
                title="Memory Fragmentation Ratio"
                content={redisInfo.mem_fragmentation_ratio}
              />
            </Grid>
            <Grid item xs={3} />
            <Grid item xs={12}>
              <Typography variant="h6" color="textSecondary">
                Connections
              </Typography>
            </Grid>
            <Grid item xs={3}>
              <MetricCard
                title="Connected Clients"
                content={redisInfo.connected_clients}
              />
            </Grid>
            <Grid item xs={3}>
              <MetricCard
                title="Connected Replicas"
                content={redisInfo.connected_slaves}
              />
            </Grid>
            <Grid item xs={6} />
            <Grid item xs={12}>
              <Typography variant="h6" color="textSecondary">
                Persistence
              </Typography>
            </Grid>
            <Grid item xs={3}>
              <MetricCard
                title="Last Save to Disk"
                content={timeAgoUnix(parseInt(redisInfo.rdb_last_save_time))}
              />
            </Grid>
            <Grid item xs={3}>
              <MetricCard
                title="Number of Changes Since Last Dump"
                content={redisInfo.rdb_changes_since_last_save}
              />
            </Grid>
            <Grid item xs={6} />
          </>
        )}
        {redisInfoRaw !== null && (
          <>
            <Grid item xs={6}>
              <Typography variant="h6" color="textSecondary">
                INFO Command Output
              </Typography>
              <SyntaxHighlighter language="yaml" style={syntaxHighlightStyle}>
                {redisInfoRaw}
              </SyntaxHighlighter>
            </Grid>
          </>
        )}
      </Grid>
    </Container>
  );
}

interface MetricCardProps {
  title: string;
  content: string;
}

function MetricCard(props: MetricCardProps) {
  return (
    <Card variant="outlined">
      <CardContent>
        <Typography
          gutterBottom
          color="textPrimary"
          variant="h5"
          align="center"
        >
          {props.content}
        </Typography>
        <Typography color="textSecondary" variant="subtitle2" align="center">
          {props.title}
        </Typography>
      </CardContent>
    </Card>
  );
}

export default connector(RedisInfoView);
