// Package cli contains the logic of the influx command line client.
package cli // import "github.com/influxdata/influxdb/cmd/influx/cli"

import (
	"bytes"
	"encoding/csv"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"net"
	"os"
	"os/signal"
	"path/filepath"
	"reflect"
	"sort"
	"strconv"
	"strings"
	"syscall"
	"text/tabwriter"

	"golang.org/x/crypto/ssh/terminal"

	"github.com/influxdata/influxdb/client"
	"github.com/influxdata/influxdb/importer/v8"
	"github.com/influxdata/influxdb/influxql"
	"github.com/influxdata/influxdb/models"
	"github.com/peterh/liner"
)

// ErrBlankCommand is returned when a parsed command is empty.
var ErrBlankCommand = errors.New("empty input")

// CommandLine holds CLI configuration and state.
type CommandLine struct {
	Line            *liner.State
	Host            string
	Port            int
	Database        string
	Ssl             bool
	RetentionPolicy string
	ClientVersion   string
	ServerVersion   string
	Pretty          bool   // controls pretty print for json
	Format          string // controls the output format.  Valid values are json, csv, or column
	Execute         string
	ShowVersion     bool
	Import          bool
	Chunked         bool
	ChunkSize       int
	Quit            chan struct{}
	IgnoreSignals   bool // Ignore signals normally caught by this process (used primarily for testing)
	ForceTTY        bool // Force the CLI to act as if it were connected to a TTY
	osSignals       chan os.Signal
	historyFilePath string

	Client         *client.Client
	ClientConfig   client.Config // Client config options.
	ImporterConfig v8.Config     // Importer configuration options.
}

// New returns an instance of CommandLine with the specified client version.
func New(version string) *CommandLine {
	return &CommandLine{
		ClientVersion: version,
		Quit:          make(chan struct{}, 1),
		osSignals:     make(chan os.Signal, 1),
		Chunked:       true,
	}
}

// Run executes the CLI.
func (c *CommandLine) Run() error {
	hasTTY := c.ForceTTY || terminal.IsTerminal(int(os.Stdin.Fd()))

	var promptForPassword bool
	// determine if they set the password flag but provided no value
	for _, v := range os.Args {
		v = strings.ToLower(v)
		if (strings.HasPrefix(v, "-password") || strings.HasPrefix(v, "--password")) && c.ClientConfig.Password == "" {
			promptForPassword = true
			break
		}
	}

	// Check if we will be able to prompt for the password later.
	if promptForPassword && !hasTTY {
		return errors.New("Unable to prompt for a password with no TTY.")
	}

	// Read environment variables for username/password.
	if c.ClientConfig.Username == "" {
		c.ClientConfig.Username = os.Getenv("INFLUX_USERNAME")
	}
	// If we are going to be prompted for a password, always use the entered password.
	if promptForPassword {
		// Open the liner (temporarily) and prompt for the password.
		p, e := func() (string, error) {
			l := liner.NewLiner()
			defer l.Close()
			return l.PasswordPrompt("password: ")
		}()
		if e != nil {
			return errors.New("Unable to parse password")
		}
		c.ClientConfig.Password = p
	} else if c.ClientConfig.Password == "" {
		c.ClientConfig.Password = os.Getenv("INFLUX_PASSWORD")
	}

	if err := c.Connect(""); err != nil {
		msg := "Please check your connection settings and ensure 'influxd' is running."
		if !c.Ssl && strings.Contains(err.Error(), "malformed HTTP response") {
			// Attempt to connect with SSL and disable secure SSL for this test.
			c.Ssl = true
			unsafeSsl := c.ClientConfig.UnsafeSsl
			c.ClientConfig.UnsafeSsl = true
			if err := c.Connect(""); err == nil {
				msg = "Please use the -ssl flag to connect using SSL."
			}
			c.Ssl = false
			c.ClientConfig.UnsafeSsl = unsafeSsl
		} else if c.Ssl && !c.ClientConfig.UnsafeSsl && strings.Contains(err.Error(), "certificate is valid for") {
			// Attempt to connect with an insecure connection just to see if it works.
			c.ClientConfig.UnsafeSsl = true
			if err := c.Connect(""); err == nil {
				msg = "You may use -unsafeSsl to connect anyway, but the SSL connection will not be secure."
			}
			c.ClientConfig.UnsafeSsl = false
		}
		return fmt.Errorf("Failed to connect to %s: %s\n%s", c.Client.Addr(), err.Error(), msg)
	}

	// Modify precision.
	c.SetPrecision(c.ClientConfig.Precision)

	if c.Execute != "" {
		// Make the non-interactive mode send everything through the CLI's parser
		// the same way the interactive mode works
		lines := strings.Split(c.Execute, "\n")
		for _, line := range lines {
			if err := c.ParseCommand(line); err != nil {
				return err
			}
		}
		return nil
	}

	if c.Import {
		addr := net.JoinHostPort(c.Host, strconv.Itoa(c.Port))
		u, e := client.ParseConnectionString(addr, c.Ssl)
		if e != nil {
			return e
		}

		// Copy the latest importer config and inject the latest client config
		// into it.
		config := c.ImporterConfig
		config.Config = c.ClientConfig
		config.URL = u

		i := v8.NewImporter(config)
		if err := i.Import(); err != nil {
			err = fmt.Errorf("ERROR: %s\n", err)
			return err
		}
		return nil
	}

	if !hasTTY {
		cmd, err := ioutil.ReadAll(os.Stdin)
		if err != nil {
			return err
		}
		return c.ExecuteQuery(string(cmd))
	}

	if !c.IgnoreSignals {
		// register OS signals for graceful termination
		signal.Notify(c.osSignals, syscall.SIGINT, syscall.SIGTERM)
	}

	c.Line = liner.NewLiner()
	defer c.Line.Close()

	c.Line.SetMultiLineMode(true)

	fmt.Printf("Connected to %s version %s\n", c.Client.Addr(), c.ServerVersion)

	c.Version()

	// Only load/write history if HOME environment variable is set.
	if homeDir := os.Getenv("HOME"); homeDir != "" {
		// Attempt to load the history file.
		c.historyFilePath = filepath.Join(homeDir, ".influx_history")
		if historyFile, err := os.Open(c.historyFilePath); err == nil {
			c.Line.ReadHistory(historyFile)
			historyFile.Close()
		}
	}

	// read from prompt until exit is run
	return c.mainLoop()
}

// mainLoop runs the main prompt loop for the CLI.
func (c *CommandLine) mainLoop() error {
	for {
		select {
		case <-c.osSignals:
			c.exit()
			return nil
		case <-c.Quit:
			c.exit()
			return nil
		default:
			l, e := c.Line.Prompt("> ")
			if e == io.EOF {
				// Instead of die, register that someone exited the program gracefully
				l = "exit"
			} else if e != nil {
				c.exit()
				return e
			}
			if err := c.ParseCommand(l); err != ErrBlankCommand && !strings.HasPrefix(strings.TrimSpace(l), "auth") {
				l = influxql.Sanitize(l)
				c.Line.AppendHistory(l)
				c.saveHistory()
			}
		}
	}
}

// ParseCommand parses an instruction and calls the related method
// or executes the command as a query against InfluxDB.
func (c *CommandLine) ParseCommand(cmd string) error {
	lcmd := strings.TrimSpace(strings.ToLower(cmd))
	tokens := strings.Fields(lcmd)

	if len(tokens) > 0 {
		switch tokens[0] {
		case "exit", "quit":
			close(c.Quit)
		case "gopher":
			c.gopher()
		case "connect":
			return c.Connect(cmd)
		case "auth":
			c.SetAuth(cmd)
		case "help":
			c.help()
		case "history":
			c.history()
		case "format":
			c.SetFormat(cmd)
		case "precision":
			c.SetPrecision(cmd)
		case "consistency":
			c.SetWriteConsistency(cmd)
		case "settings":
			c.Settings()
		case "chunked":
			c.Chunked = !c.Chunked
			if c.Chunked {
				fmt.Println("chunked responses enabled")
			} else {
				fmt.Println("chunked reponses disabled")
			}
		case "chunk":
			c.SetChunkSize(cmd)
		case "pretty":
			c.Pretty = !c.Pretty
			if c.Pretty {
				fmt.Println("Pretty print enabled")
			} else {
				fmt.Println("Pretty print disabled")
			}
		case "use":
			c.use(cmd)
		case "insert":
			return c.Insert(cmd)
		case "clear":
			c.clear(cmd)
		default:
			return c.ExecuteQuery(cmd)
		}

		return nil
	}
	return ErrBlankCommand
}

// Connect connects to a server.
func (c *CommandLine) Connect(cmd string) error {
	// Remove the "connect" keyword if it exists
	addr := strings.TrimSpace(strings.Replace(cmd, "connect", "", -1))
	if addr == "" {
		// If they didn't provide a connection string, use the current settings
		addr = net.JoinHostPort(c.Host, strconv.Itoa(c.Port))
	}

	URL, err := client.ParseConnectionString(addr, c.Ssl)
	if err != nil {
		return err
	}

	// Create copy of the current client config and create a new client.
	ClientConfig := c.ClientConfig
	ClientConfig.UserAgent = "InfluxDBShell/" + c.ClientVersion
	ClientConfig.URL = URL

	client, err := client.NewClient(ClientConfig)
	if err != nil {
		return fmt.Errorf("Could not create client %s", err)
	}
	c.Client = client

	_, v, err := c.Client.Ping()
	if err != nil {
		return err
	}
	c.ServerVersion = v

	// Update the command with the current connection information
	if host, port, err := net.SplitHostPort(ClientConfig.URL.Host); err == nil {
		c.Host = host
		if i, err := strconv.Atoi(port); err == nil {
			c.Port = i
		}
	}

	return nil
}

// SetAuth sets client authentication credentials.
func (c *CommandLine) SetAuth(cmd string) {
	// If they pass in the entire command, we should parse it
	// auth <username> <password>
	args := strings.Fields(cmd)
	if len(args) == 3 {
		args = args[1:]
	} else {
		args = []string{}
	}

	if len(args) == 2 {
		c.ClientConfig.Username = args[0]
		c.ClientConfig.Password = args[1]
	} else {
		u, e := c.Line.Prompt("username: ")
		if e != nil {
			fmt.Printf("Unable to process input: %s", e)
			return
		}
		c.ClientConfig.Username = strings.TrimSpace(u)
		p, e := c.Line.PasswordPrompt("password: ")
		if e != nil {
			fmt.Printf("Unable to process input: %s", e)
			return
		}
		c.ClientConfig.Password = p
	}

	// Update the client as well
	c.Client.SetAuth(c.ClientConfig.Username, c.ClientConfig.Password)
}

func (c *CommandLine) clear(cmd string) {
	args := strings.Split(strings.TrimSuffix(strings.TrimSpace(cmd), ";"), " ")
	v := strings.ToLower(strings.Join(args[1:], " "))
	switch v {
	case "database", "db":
		c.Database = ""
		fmt.Println("database context cleared")
		return
	case "retention policy", "rp":
		c.RetentionPolicy = ""
		fmt.Println("retention policy context cleared")
		return
	default:
		if len(args) > 1 {
			fmt.Printf("invalid command %q.\n", v)
		}
		fmt.Println(`Possible commands for 'clear' are:
    # Clear the database context
    clear database
    clear db

    # Clear the retention policy context
    clear retention policy
    clear rp
		`)
	}
}

func (c *CommandLine) use(cmd string) {
	args := strings.Split(strings.TrimSuffix(strings.TrimSpace(cmd), ";"), " ")
	if len(args) != 2 {
		fmt.Printf("Could not parse database name from %q.\n", cmd)
		return
	}

	stmt := args[1]
	db, rp, err := parseDatabaseAndRetentionPolicy([]byte(stmt))
	if err != nil {
		fmt.Printf("Unable to parse database or retention policy from %s", stmt)
		return
	}

	if !c.databaseExists(db) {
		return
	}

	c.Database = db
	fmt.Printf("Using database %s\n", db)

	if rp != "" {
		if !c.retentionPolicyExists(db, rp) {
			return
		}
		c.RetentionPolicy = rp
		fmt.Printf("Using retention policy %s\n", rp)
	}
}

func (c *CommandLine) databaseExists(db string) bool {
	// Validate if specified database exists
	response, err := c.Client.Query(client.Query{Command: "SHOW DATABASES"})
	if err != nil {
		fmt.Printf("ERR: %s\n", err)
		return false
	} else if err := response.Error(); err != nil {
		if c.ClientConfig.Username == "" {
			fmt.Printf("ERR: %s\n", err)
			return false
		}
		// TODO(jsternberg): Fix SHOW DATABASES to be user-aware #6397.
		// If we are unable to run SHOW DATABASES, display a warning and use the
		// database anyway in case the person doesn't have permission to run the
		// command, but does have permission to use the database.
		fmt.Printf("WARN: %s\n", err)
	} else {
		// Verify the provided database exists
		if databaseExists := func() bool {
			for _, result := range response.Results {
				for _, row := range result.Series {
					if row.Name == "databases" {
						for _, values := range row.Values {
							for _, database := range values {
								if database == db {
									return true
								}
							}
						}
					}
				}
			}
			return false
		}(); !databaseExists {
			fmt.Printf("ERR: Database %s doesn't exist. Run SHOW DATABASES for a list of existing databases.\n", db)
			return false
		}
	}
	return true
}

func (c *CommandLine) retentionPolicyExists(db, rp string) bool {
	// Validate if specified database exists
	response, err := c.Client.Query(client.Query{Command: fmt.Sprintf("SHOW RETENTION POLICIES ON %q", db)})
	if err != nil {
		fmt.Printf("ERR: %s\n", err)
		return false
	} else if err := response.Error(); err != nil {
		if c.ClientConfig.Username == "" {
			fmt.Printf("ERR: %s\n", err)
			return false
		}
		fmt.Printf("WARN: %s\n", err)
	} else {
		// Verify the provided database exists
		if retentionPolicyExists := func() bool {
			for _, result := range response.Results {
				for _, row := range result.Series {
					for _, values := range row.Values {
						for i, v := range values {
							if i != 0 {
								continue
							}
							if v == rp {
								return true
							}
						}
					}
				}
			}
			return false
		}(); !retentionPolicyExists {
			fmt.Printf("ERR: RETENTION POLICY %s doesn't exist. Run SHOW RETENTION POLICIES ON %q for a list of existing retention polices.\n", rp, db)
			return false
		}
	}
	return true
}

// SetChunkSize sets the chunk size
// 0 sets it back to the default
func (c *CommandLine) SetChunkSize(cmd string) {
	// normalize cmd
	cmd = strings.ToLower(cmd)
	cmd = strings.Join(strings.Fields(cmd), " ")

	// Remove the "chunk size" keyword if it exists
	cmd = strings.TrimPrefix(cmd, "chunk size ")

	// Remove the "chunk" keyword if it exists
	// allows them to use `chunk 50` as a shortcut
	cmd = strings.TrimPrefix(cmd, "chunk ")

	if n, err := strconv.ParseInt(cmd, 10, 64); err == nil {
		c.ChunkSize = int(n)
		if c.ChunkSize <= 0 {
			c.ChunkSize = 0
		}
		fmt.Printf("chunk size set to %d\n", c.ChunkSize)
	} else {
		fmt.Printf("unable to parse chunk size from %q\n", cmd)
	}
}

// SetPrecision sets client precision.
func (c *CommandLine) SetPrecision(cmd string) {
	// normalize cmd
	cmd = strings.ToLower(cmd)

	// Remove the "precision" keyword if it exists
	cmd = strings.TrimSpace(strings.Replace(cmd, "precision", "", -1))

	switch cmd {
	case "h", "m", "s", "ms", "u", "ns":
		c.ClientConfig.Precision = cmd
		c.Client.SetPrecision(c.ClientConfig.Precision)
	case "rfc3339":
		c.ClientConfig.Precision = ""
		c.Client.SetPrecision(c.ClientConfig.Precision)
	default:
		fmt.Printf("Unknown precision %q. Please use rfc3339, h, m, s, ms, u or ns.\n", cmd)
	}
}

// SetFormat sets output format.
func (c *CommandLine) SetFormat(cmd string) {
	// Remove the "format" keyword if it exists
	cmd = strings.TrimSpace(strings.Replace(cmd, "format", "", -1))
	// normalize cmd
	cmd = strings.ToLower(cmd)

	switch cmd {
	case "json", "csv", "column":
		c.Format = cmd
	default:
		fmt.Printf("Unknown format %q. Please use json, csv, or column.\n", cmd)
	}
}

// SetWriteConsistency sets write consistency level.
func (c *CommandLine) SetWriteConsistency(cmd string) {
	// Remove the "consistency" keyword if it exists
	cmd = strings.TrimSpace(strings.Replace(cmd, "consistency", "", -1))
	// normalize cmd
	cmd = strings.ToLower(cmd)

	_, err := models.ParseConsistencyLevel(cmd)
	if err != nil {
		fmt.Printf("Unknown consistency level %q. Please use any, one, quorum, or all.\n", cmd)
		return
	}
	c.ClientConfig.WriteConsistency = cmd
}

// isWhitespace returns true if the rune is a space, tab, or newline.
func isWhitespace(ch rune) bool { return ch == ' ' || ch == '\t' || ch == '\n' }

// isLetter returns true if the rune is a letter.
func isLetter(ch rune) bool { return (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') }

// isDigit returns true if the rune is a digit.
func isDigit(ch rune) bool { return (ch >= '0' && ch <= '9') }

// isIdentFirstChar returns true if the rune can be used as the first char in an unquoted identifer.
func isIdentFirstChar(ch rune) bool { return isLetter(ch) || ch == '_' }

// isIdentChar returns true if the rune can be used in an unquoted identifier.
func isNotIdentChar(ch rune) bool { return !(isLetter(ch) || isDigit(ch) || ch == '_') }

func parseUnquotedIdentifier(stmt string) (string, string) {
	if fields := strings.FieldsFunc(stmt, isNotIdentChar); len(fields) > 0 {
		return fields[0], strings.TrimPrefix(stmt, fields[0])
	}
	return "", stmt
}

func parseDoubleQuotedIdentifier(stmt string) (string, string) {
	escapeNext := false
	fields := strings.FieldsFunc(stmt, func(ch rune) bool {
		if ch == '\\' {
			escapeNext = true
		} else if ch == '"' {
			if !escapeNext {
				return true
			}
			escapeNext = false
		}
		return false
	})
	if len(fields) > 0 {
		return fields[0], strings.TrimPrefix(stmt, "\""+fields[0]+"\"")
	}
	return "", stmt
}

func parseNextIdentifier(stmt string) (ident, remainder string) {
	if len(stmt) > 0 {
		switch {
		case isWhitespace(rune(stmt[0])):
			return parseNextIdentifier(stmt[1:])
		case isIdentFirstChar(rune(stmt[0])):
			return parseUnquotedIdentifier(stmt)
		case stmt[0] == '"':
			return parseDoubleQuotedIdentifier(stmt)
		}
	}
	return "", stmt
}

func (c *CommandLine) parseInto(stmt string) *client.BatchPoints {
	ident, stmt := parseNextIdentifier(stmt)
	db, rp := c.Database, c.RetentionPolicy
	if strings.HasPrefix(stmt, ".") {
		db = ident
		ident, stmt = parseNextIdentifier(stmt[1:])
	}
	if strings.HasPrefix(stmt, " ") {
		rp = ident
		stmt = stmt[1:]
	}

	return &client.BatchPoints{
		Points: []client.Point{
			client.Point{Raw: stmt},
		},
		Database:         db,
		RetentionPolicy:  rp,
		Precision:        c.ClientConfig.Precision,
		WriteConsistency: c.ClientConfig.WriteConsistency,
	}
}

func (c *CommandLine) parseInsert(stmt string) (*client.BatchPoints, error) {
	i, point := parseNextIdentifier(stmt)
	if !strings.EqualFold(i, "insert") {
		return nil, fmt.Errorf("found %s, expected INSERT\n", i)
	}
	if i, r := parseNextIdentifier(point); strings.EqualFold(i, "into") {
		bp := c.parseInto(r)
		return bp, nil
	}
	return &client.BatchPoints{
		Points: []client.Point{
			client.Point{Raw: point},
		},
		Database:         c.Database,
		RetentionPolicy:  c.RetentionPolicy,
		Precision:        c.ClientConfig.Precision,
		WriteConsistency: c.ClientConfig.WriteConsistency,
	}, nil
}

// Insert runs an INSERT statement.
func (c *CommandLine) Insert(stmt string) error {
	bp, err := c.parseInsert(stmt)
	if err != nil {
		fmt.Printf("ERR: %s\n", err)
		return nil
	}
	if _, err := c.Client.Write(*bp); err != nil {
		fmt.Printf("ERR: %s\n", err)
		if c.Database == "" {
			fmt.Println("Note: error may be due to not setting a database or retention policy.")
			fmt.Println(`Please set a database with the command "use <database>" or`)
			fmt.Println("INSERT INTO <database>.<retention-policy> <point>")
		}
	}
	return nil
}

// query creates a query struct to be used with the client.
func (c *CommandLine) query(query string) client.Query {
	return client.Query{
		Command:   query,
		Database:  c.Database,
		Chunked:   c.Chunked,
		ChunkSize: c.ChunkSize,
	}
}

// ExecuteQuery runs any query statement.
func (c *CommandLine) ExecuteQuery(query string) error {
	// If we have a retention policy, we need to rewrite the statement sources
	if c.RetentionPolicy != "" {
		pq, err := influxql.NewParser(strings.NewReader(query)).ParseQuery()
		if err != nil {
			fmt.Printf("ERR: %s\n", err)
			return err
		}
		for _, stmt := range pq.Statements {
			if selectStatement, ok := stmt.(*influxql.SelectStatement); ok {
				influxql.WalkFunc(selectStatement.Sources, func(n influxql.Node) {
					if t, ok := n.(*influxql.Measurement); ok {
						if t.Database == "" && c.Database != "" {
							t.Database = c.Database
						}
						if t.RetentionPolicy == "" && c.RetentionPolicy != "" {
							t.RetentionPolicy = c.RetentionPolicy
						}
					}
				})
			}
		}
		query = pq.String()
	}
	response, err := c.Client.Query(c.query(query))
	if err != nil {
		fmt.Printf("ERR: %s\n", err)
		return err
	}
	c.FormatResponse(response, os.Stdout)
	if err := response.Error(); err != nil {
		fmt.Printf("ERR: %s\n", response.Error())
		if c.Database == "" {
			fmt.Println("Warning: It is possible this error is due to not setting a database.")
			fmt.Println(`Please set a database with the command "use <database>".`)
		}
		return err
	}
	return nil
}

// FormatResponse formats output to the previously chosen format.
func (c *CommandLine) FormatResponse(response *client.Response, w io.Writer) {
	switch c.Format {
	case "json":
		c.writeJSON(response, w)
	case "csv":
		c.writeCSV(response, w)
	case "column":
		c.writeColumns(response, w)
	default:
		fmt.Fprintf(w, "Unknown output format %q.\n", c.Format)
	}
}

func (c *CommandLine) writeJSON(response *client.Response, w io.Writer) {
	var data []byte
	var err error
	if c.Pretty {
		data, err = json.MarshalIndent(response, "", "    ")
	} else {
		data, err = json.Marshal(response)
	}
	if err != nil {
		fmt.Fprintf(w, "Unable to parse json: %s\n", err)
		return
	}
	fmt.Fprintln(w, string(data))
}

func tagsEqual(prev, current map[string]string) bool {
	return reflect.DeepEqual(prev, current)
}

func columnsEqual(prev, current []string) bool {
	return reflect.DeepEqual(prev, current)
}

func headersEqual(prev, current models.Row) bool {
	if prev.Name != current.Name {
		return false
	}
	return tagsEqual(prev.Tags, current.Tags) && columnsEqual(prev.Columns, current.Columns)
}

func (c *CommandLine) writeCSV(response *client.Response, w io.Writer) {
	csvw := csv.NewWriter(w)
	var previousHeaders models.Row
	for _, result := range response.Results {
		suppressHeaders := len(result.Series) > 0 && headersEqual(previousHeaders, result.Series[0])
		if !suppressHeaders && len(result.Series) > 0 {
			previousHeaders = models.Row{
				Name:    result.Series[0].Name,
				Tags:    result.Series[0].Tags,
				Columns: result.Series[0].Columns,
			}
		}

		// Create a tabbed writer for each result as they won't always line up
		rows := c.formatResults(result, "\t", suppressHeaders)
		for _, r := range rows {
			csvw.Write(strings.Split(r, "\t"))
		}
	}
	csvw.Flush()
}

func (c *CommandLine) writeColumns(response *client.Response, w io.Writer) {
	// Create a tabbed writer for each result as they won't always line up
	writer := new(tabwriter.Writer)
	writer.Init(w, 0, 8, 1, ' ', 0)

	var previousHeaders models.Row
	for i, result := range response.Results {
		// Print out all messages first
		for _, m := range result.Messages {
			fmt.Fprintf(w, "%s: %s.\n", m.Level, m.Text)
		}
		// Check to see if the headers are the same as the previous row.  If so, suppress them in the output
		suppressHeaders := len(result.Series) > 0 && headersEqual(previousHeaders, result.Series[0])
		if !suppressHeaders && len(result.Series) > 0 {
			previousHeaders = models.Row{
				Name:    result.Series[0].Name,
				Tags:    result.Series[0].Tags,
				Columns: result.Series[0].Columns,
			}
		}

		// If we are suppressing headers, don't output the extra line return. If we
		// aren't suppressing headers, then we put out line returns between results
		// (not before the first result, and not after the last result).
		if !suppressHeaders && i > 0 {
			fmt.Fprintln(writer, "")
		}

		rows := c.formatResults(result, "\t", suppressHeaders)
		for _, r := range rows {
			fmt.Fprintln(writer, r)
		}

	}
	writer.Flush()
}

// formatResults will behave differently if you are formatting for columns or csv
func (c *CommandLine) formatResults(result client.Result, separator string, suppressHeaders bool) []string {
	rows := []string{}
	// Create a tabbed writer for each result as they won't always line up
	for i, row := range result.Series {
		// gather tags
		tags := []string{}
		for k, v := range row.Tags {
			tags = append(tags, fmt.Sprintf("%s=%s", k, v))
			sort.Strings(tags)
		}

		columnNames := []string{}

		// Only put name/tags in a column if format is csv
		if c.Format == "csv" {
			if len(tags) > 0 {
				columnNames = append([]string{"tags"}, columnNames...)
			}

			if row.Name != "" {
				columnNames = append([]string{"name"}, columnNames...)
			}
		}

		columnNames = append(columnNames, row.Columns...)

		// Output a line separator if we have more than one set or results and format is column
		if i > 0 && c.Format == "column" && !suppressHeaders {
			rows = append(rows, "")
		}

		// If we are column format, we break out the name/tag to separate lines
		if c.Format == "column" && !suppressHeaders {
			if row.Name != "" {
				n := fmt.Sprintf("name: %s", row.Name)
				rows = append(rows, n)
			}
			if len(tags) > 0 {
				t := fmt.Sprintf("tags: %s", (strings.Join(tags, ", ")))
				rows = append(rows, t)
			}
		}

		if !suppressHeaders {
			rows = append(rows, strings.Join(columnNames, separator))
		}

		// if format is column, write dashes under each column
		if c.Format == "column" && !suppressHeaders {
			lines := []string{}
			for _, columnName := range columnNames {
				lines = append(lines, strings.Repeat("-", len(columnName)))
			}
			rows = append(rows, strings.Join(lines, separator))
		}

		for _, v := range row.Values {
			var values []string
			if c.Format == "csv" {
				if row.Name != "" {
					values = append(values, row.Name)
				}
				if len(tags) > 0 {
					values = append(values, strings.Join(tags, ","))
				}
			}

			for _, vv := range v {
				values = append(values, interfaceToString(vv))
			}
			rows = append(rows, strings.Join(values, separator))
		}
	}
	return rows
}

func interfaceToString(v interface{}) string {
	switch t := v.(type) {
	case nil:
		return ""
	case bool:
		return fmt.Sprintf("%v", v)
	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, uintptr:
		return fmt.Sprintf("%d", t)
	case float32, float64:
		return fmt.Sprintf("%v", t)
	default:
		return fmt.Sprintf("%v", t)
	}
}

// Settings prints current settings.
func (c *CommandLine) Settings() {
	w := new(tabwriter.Writer)
	w.Init(os.Stdout, 0, 1, 1, ' ', 0)
	fmt.Fprintln(w, "Setting\tValue")
	fmt.Fprintln(w, "--------\t--------")
	if c.Port > 0 {
		fmt.Fprintf(w, "Host\t%s:%d\n", c.Host, c.Port)
	} else {
		fmt.Fprintf(w, "Host\t%s\n", c.Host)
	}
	fmt.Fprintf(w, "Username\t%s\n", c.ClientConfig.Username)
	fmt.Fprintf(w, "Database\t%s\n", c.Database)
	fmt.Fprintf(w, "RetentionPolicy\t%s\n", c.RetentionPolicy)
	fmt.Fprintf(w, "Pretty\t%v\n", c.Pretty)
	fmt.Fprintf(w, "Format\t%s\n", c.Format)
	fmt.Fprintf(w, "Write Consistency\t%s\n", c.ClientConfig.WriteConsistency)
	fmt.Fprintf(w, "Chunked\t%v\n", c.Chunked)
	fmt.Fprintf(w, "Chunk Size\t%d\n", c.ChunkSize)
	fmt.Fprintln(w)
	w.Flush()
}

func (c *CommandLine) help() {
	fmt.Println(`Usage:
        connect <host:port>   connects to another node specified by host:port
        auth                  prompts for username and password
        pretty                toggles pretty print for the json format
        chunked               turns on chunked responses from server
        chunk size <size>     sets the size of the chunked responses.  Set to 0 to reset to the default chunked size
        use <db_name>         sets current database
        format <format>       specifies the format of the server responses: json, csv, or column
        precision <format>    specifies the format of the timestamp: rfc3339, h, m, s, ms, u or ns
        consistency <level>   sets write consistency level: any, one, quorum, or all
        history               displays command history
        settings              outputs the current settings for the shell
        clear                 clears settings such as database or retention policy.  run 'clear' for help
        exit/quit/ctrl+d      quits the influx shell

        show databases        show database names
        show series           show series information
        show measurements     show measurement information
        show tag keys         show tag key information
        show field keys       show field key information

        A full list of influxql commands can be found at:
        https://docs.influxdata.com/influxdb/latest/query_language/spec/
`)
}

func (c *CommandLine) history() {
	var buf bytes.Buffer
	c.Line.WriteHistory(&buf)
	fmt.Print(buf.String())
}

func (c *CommandLine) saveHistory() {
	if historyFile, err := os.Create(c.historyFilePath); err != nil {
		fmt.Printf("There was an error writing history file: %s\n", err)
	} else {
		c.Line.WriteHistory(historyFile)
		historyFile.Close()
	}
}

func (c *CommandLine) gopher() {
	fmt.Println(`
                                          .-::-::://:-::-    .:/++/'
                                     '://:-''/oo+//++o+/.://o-    ./+:
                                  .:-.    '++-         .o/ '+yydhy'  o-
                               .:/.      .h:         :osoys  .smMN-  :/
                            -/:.'        s-         /MMMymh.   '/y/  s'
                         -+s:''''        d          -mMMms//     '-/o:
                       -/++/++/////:.    o:          '... s-        :s.
                     :+-+s-'       ':/'  's-             /+          'o:
                   '+-'o:        /ydhsh.  '//.        '-o-             o-
                  .y. o:        .MMMdm+y    ':+++:::/+:.'               s:
                .-h/  y-        'sdmds'h -+ydds:::-.'                   'h.
             .//-.d'  o:          '.' 'dsNMMMNh:.:++'                    :y
            +y.  'd   's.            .s:mddds:     ++                     o/
           'N-  odd    'o/.       './o-s-'   .---+++'                      o-
           'N'  yNd      .://:/:::::. -s   -+/s/./s'                       'o/'
            so'  .h         ''''       ////s: '+. .s                         +y'
             os/-.y'                       's' 'y::+                          +d'
               '.:o/                        -+:-:.'                            so.---.'
                   o'                                                          'd-.''/s'
                   .s'                                                          :y.''.y
                    -s                                                           mo:::'
                     ::                                                          yh
                      //                                      ''''               /M'
                       o+                                    .s///:/.            'N:
                        :+                                   /:    -s'            ho
                         's-                               -/s/:+/.+h'            +h
                           ys'                            ':'    '-.              -d
                            oh                                                    .h
                             /o                                                   .s
                              s.                                                  .h
                              -y                                                  .d
                               m/                                                 -h
                               +d                                                 /o
                               'N-                                                y:
                                h:                                                m.
                                s-                                               -d
                                o-                                               s+
                                +-                                              'm'
                                s/                                              oo--.
                                y-                                             /s  ':+'
                                s'                                           'od--' .d:
                                -+                                         ':o: ':+-/+
                                 y-                                      .:+-      '
                                //o-                                 '.:+/.
                                .-:+/'                           ''-/+/.
                                    ./:'                    ''.:o+/-'
                                      .+o:/:/+-'      ''.-+ooo/-'
                                         o:   -h///++////-.
                                        /:   .o/
                                       //+  'y
                                       ./sooy.

`)
}

// Version prints the CLI version.
func (c *CommandLine) Version() {
	fmt.Println("InfluxDB shell version:", c.ClientVersion)
}

func (c *CommandLine) exit() {
	// write to history file
	c.saveHistory()
	// release line resources
	c.Line.Close()
	c.Line = nil
}
