package settings

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/url"
	"strconv"

	"git.bit5.ru/backend/errors"
)

// username/password - auth credentials
// database - select the current default database
// read_timeout/write_timeout - timeout in second
// no_delay - disable/enable the Nagle Algorithm for tcp socket (default is 'true' - disable)
// alt_hosts - comma separated list of single address host for load-balancing
// connection_open_strategy - random/in_order (default random).
// random - choose random server from set
// in_order - first live server is chosen in specified order
// block_size - maximum rows in block (default is 1000000). If the rows are larger then the data will be split into several blocks to send them to the server
// pool size - maximum amount of preallocated byte chunks used in queries (default is 100). Decrease this if you experience memory problems at the expense of more GC pressure and vice versa.
// debug - enable debug output (boolean value)

// Load
func Load(path string) (ClickhouseSettings, error) {
	bytes, err := ioutil.ReadFile(path)
	if err != nil {
		return ClickhouseSettings{}, errors.WithStack(err)
	}
	settings := ClickhouseSettings{}
	if err := json.Unmarshal(bytes, &settings); err != nil {
		return ClickhouseSettings{}, errors.WithStack(err)
	}

	return settings, nil
}

// ClickhouseSettings
type ClickhouseSettings struct {
	Host     string `json:"host"`
	Port     int    `json:"port"`
	Database string `json:"database"`
	Username string `json:"username"`
	Password string `json:"password"`

	Options map[string]json.RawMessage `json:"opts"`
}

func (s ClickhouseSettings) DSN() string {
	options := url.Values{
		"database": []string{s.Database},
	}
	if len(s.Username) > 0 {
		options.Set("username", s.Username)
	}
	if len(s.Password) > 0 {
		options.Set("password", s.Password)
	}

	for name, value := range s.Options {
		var valueString string

		if value[0] == '"' {
			if err := json.Unmarshal(value, &valueString); err != nil {
				panic(err)
			}
		} else {
			var valueInt int
			if err := json.Unmarshal(value, &valueInt); err != nil {
				panic(err)
			}
			valueString = strconv.Itoa(valueInt)
		}

		options.Set(name, valueString)
	}

	uri := url.URL{
		Scheme:   "tcp",
		Host:     fmt.Sprintf("%s:%d", s.Host, s.Port),
		RawQuery: options.Encode(),
	}

	return uri.String()
}