package clickhouse

import (
	"bufio"
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"

	"example.com/siem-greenfield/internal/config"
	"example.com/siem-greenfield/internal/contracts"
)

type Client struct {
	base, db, user, pass string
	hc                   *http.Client
}

func New(cfg config.Config) *Client {
	return &Client{base: cfg.ClickHouseURL, db: cfg.ClickHouseDB, user: cfg.ClickHouseUser, pass: cfg.ClickHousePassword, hc: &http.Client{Timeout: 30 * time.Second}}
}
func (c *Client) request(ctx context.Context, query string, body io.Reader) (*http.Response, error) {
	u := c.base + "/?query=" + url.QueryEscape(query)
	req, e := http.NewRequestWithContext(ctx, http.MethodPost, u, body)
	if e != nil {
		return nil, e
	}
	req.SetBasicAuth(c.user, c.pass)
	return c.hc.Do(req)
}
func (c *Client) Exec(ctx context.Context, q string) error {
	r, e := c.request(ctx, q, nil)
	if e != nil {
		return e
	}
	defer r.Body.Close()
	if r.StatusCode/100 != 2 {
		b, _ := io.ReadAll(io.LimitReader(r.Body, 8192))
		return fmt.Errorf("clickhouse %s: %s", r.Status, string(b))
	}
	return nil
}
func (c *Client) InsertEvents(ctx context.Context, events []contracts.CanonicalEvent) error {
	if len(events) == 0 {
		return nil
	}
	var b bytes.Buffer
	enc := json.NewEncoder(&b)
	enc.SetEscapeHTML(false)
	for i := range events {
		if e := enc.Encode(events[i]); e != nil {
			return e
		}
	}
	q := `INSERT INTO ` + Ident(c.db) + `.events FORMAT JSONEachRow`
	r, e := c.request(ctx, q, &b)
	if e != nil {
		return e
	}
	defer r.Body.Close()
	if r.StatusCode/100 != 2 {
		x, _ := io.ReadAll(io.LimitReader(r.Body, 16384))
		return fmt.Errorf("clickhouse insert %s: %s", r.Status, string(x))
	}
	return nil
}
func (c *Client) QueryJSON(ctx context.Context, q string) ([]map[string]any, error) {
	if !strings.Contains(strings.ToUpper(q), "FORMAT") {
		q += " FORMAT JSONEachRow"
	}
	r, e := c.request(ctx, q, nil)
	if e != nil {
		return nil, e
	}
	defer r.Body.Close()
	if r.StatusCode/100 != 2 {
		x, _ := io.ReadAll(io.LimitReader(r.Body, 16384))
		return nil, fmt.Errorf("clickhouse query %s: %s", r.Status, string(x))
	}
	var out []map[string]any
	s := bufio.NewScanner(r.Body)
	buf := make([]byte, 0, 64*1024)
	s.Buffer(buf, 4*1024*1024)
	for s.Scan() {
		var m map[string]any
		if e := json.Unmarshal(s.Bytes(), &m); e != nil {
			return nil, e
		}
		out = append(out, m)
	}
	return out, s.Err()
}
func Q(s string) string     { return "'" + strings.ReplaceAll(s, "'", "''") + "'" }
func Ident(s string) string { return "`" + strings.ReplaceAll(s, "`", "``") + "`" }