package cli

import (
	"fmt"

	"github.com/spf13/cobra"

	"github.com/neilotoole/sq/libsq/driver"
	"github.com/neilotoole/sq/libsq/errz"
	"github.com/neilotoole/sq/libsq/source"
	"github.com/neilotoole/sq/libsq/stringz"
)

func newTblCmd() (*cobra.Command, runFunc) {
	cmd := &cobra.Command{
		Use:   "tbl",
		Short: "Common actions on tables (copy, truncate, drop)",

		Example: `  # Copy table actor to new table actor2
  sq tbl copy @sakila_sl3.actor actor2

  # Truncate table actor2
  sq tbl truncate @sakila_sl3.actor2

  # Drop table actor2
  sq tbl drop @sakila_sl3.actor2`,
	}

	return cmd, func(rc *RunContext, cmd *cobra.Command, args []string) error {
		return cmd.Help()
	}
}

func newTblCopyCmd() (*cobra.Command, runFunc) {
	cmd := &cobra.Command{
		Use:   "copy @HANDLE.TABLE NEWTABLE",
		Short: "Make a copy of a table",
		Long:  `Make a copy of a table in the same database. The table data is also copied by default.`,
		Example: `  # Copy table "actor" in @sakila_sl3" to new table "actor2"
  sq tbl copy @sakila_sl3.actor .actor2

  # Copy table "actor" in active src to table "actor2"
  sq tbl copy .actor .actor2

  # Copy table "actor" in active src to generated table name (e.g. "@sakila_sl3.actor_copy__1ae03e9b")
  sq tbl copy .actor

  # Copy table structure, but don't copy table data
  sq tbl copy --data=false .actor
`,
	}

	cmd.Flags().BoolP(flagJSON, flagJSONShort, false, flagJSONUsage)
	cmd.Flags().Bool(flagTblData, true, flagTblDataUsage)

	return cmd, execTblCopy
}

func execTblCopy(rc *RunContext, cmd *cobra.Command, args []string) error {
	if len(args) == 0 || len(args) > 2 {
		return errz.New("one or two table args required")
	}

	tblHandles, err := parseTableHandleArgs(rc.registry, rc.Config.Sources, args)
	if err != nil {
		return err
	}

	if tblHandles[0].tbl == "" {
		return errz.Errorf("arg %q does not specify a table name")
	}

	switch len(tblHandles) {
	case 1:
		// Make a copy of the first tbl handle
		tblHandles = append(tblHandles, tblHandles[0])
		// But we can't copy the table to itself, so we create a new name
		tblHandles[1].tbl = stringz.UniqTableName(tblHandles[0].tbl + "_copy")
	case 2:
		if tblHandles[1].tbl == "" {
			tblHandles[1].tbl = stringz.UniqTableName(tblHandles[0].tbl + "_copy")
		}
	default:
		return errz.New("one or two table args required")
	}

	if tblHandles[0].src.Handle != tblHandles[1].src.Handle {
		return errz.Errorf("tbl copy only works on the same source, but got %s.%s --> %s.%s",
			tblHandles[0].handle, tblHandles[0].tbl,
			tblHandles[1].handle, tblHandles[1].tbl)
	}

	if tblHandles[0].tbl == tblHandles[1].tbl {
		return errz.Errorf("cannot copy table %s.%s to itself", tblHandles[0].handle, tblHandles[0].tbl)
	}

	sqlDrvr, ok := tblHandles[0].drvr.(driver.SQLDriver)
	if !ok {
		return errz.Errorf("source type %q (%s) doesn't support dropping tables", tblHandles[0].src.Type, tblHandles[0].src.Handle)
	}

	copyData := true // copy data by default
	if cmdFlagChanged(cmd, flagTblData) {
		copyData, err = cmd.Flags().GetBool(flagTblData)
		if err != nil {
			return errz.Err(err)
		}
	}

	var dbase driver.Database
	dbase, err = rc.databases.Open(rc.Context, tblHandles[0].src)
	if err != nil {
		return err
	}

	copied, err := sqlDrvr.CopyTable(rc.Context, dbase.DB(), tblHandles[0].tbl, tblHandles[1].tbl, copyData)
	if err != nil {
		return errz.Wrapf(err, "failed tbl copy %s.%s --> %s.%s",
			tblHandles[0].handle, tblHandles[0].tbl,
			tblHandles[1].handle, tblHandles[1].tbl)
	}

	msg := fmt.Sprintf("Copied table: %s.%s --> %s.%s",
		tblHandles[0].handle, tblHandles[0].tbl,
		tblHandles[1].handle, tblHandles[1].tbl)

	if copyData {
		switch copied {
		case 1:
			msg += " (1 row copied)"
		default:
			msg += fmt.Sprintf(" (%d rows copied)", copied)
		}
	}

	fmt.Fprintln(rc.Out, msg)
	return nil
}

func newTblTruncateCmd() (*cobra.Command, runFunc) {
	cmd := &cobra.Command{
		Use:   "truncate @HANDLE.TABLE",
		Short: "Truncate one or more tables",
		Example: `  # truncate table "actor"" in source @sakila_sl3
  sq tbl truncate @sakila_sl3.actor

  # truncate table "payment"" in the active src
  sq tbl truncate .payment

  # truncate multiple tables
  sq tbl truncate .payment @sakila_sl3.actor
`,
	}

	cmd.Flags().BoolP(flagJSON, flagJSONShort, false, flagJSONUsage)
	cmd.Flags().BoolP(flagTable, flagTableShort, false, flagTableUsage)

	return cmd, execTblTruncate
}

func execTblTruncate(rc *RunContext, cmd *cobra.Command, args []string) (err error) {
	var tblHandles []tblHandle
	tblHandles, err = parseTableHandleArgs(rc.registry, rc.Config.Sources, args)
	if err != nil {
		return err
	}

	for _, tblH := range tblHandles {
		var affected int64
		affected, err = tblH.drvr.Truncate(rc.Context, tblH.src, tblH.tbl, true)
		if err != nil {
			return err
		}

		msg := fmt.Sprintf("Truncated %d row(s) from %s.%s", affected, tblH.src.Handle, tblH.tbl)
		msg = stringz.Plu(msg, int(affected))
		fmt.Fprintln(rc.Out, msg)
	}

	return nil
}

func newTblDropCmd() (*cobra.Command, runFunc) {
	cmd := &cobra.Command{
		Use:   "drop @HANDLE.TABLE",
		Short: "Drop one or more tables",
		Example: `# drop table "actor" in src @sakila_sl3
  sq tbl drop @sakila_sl3.actor

  # drop table "payment"" in the active src
  sq tbl drop .payment

  # drop multiple tables
  sq drop .payment @sakila_sl3.actor
`,
	}

	return cmd, execTblDrop
}

func execTblDrop(rc *RunContext, cmd *cobra.Command, args []string) (err error) {
	var tblHandles []tblHandle
	tblHandles, err = parseTableHandleArgs(rc.registry, rc.Config.Sources, args)
	if err != nil {
		return err
	}

	for _, tblH := range tblHandles {
		sqlDrvr, ok := tblH.drvr.(driver.SQLDriver)
		if !ok {
			return errz.Errorf("source type %q (%s) doesn't support dropping tables", tblH.src.Type, tblH.src.Handle)
		}

		var dbase driver.Database
		dbase, err = rc.databases.Open(rc.Context, tblH.src)
		if err != nil {
			return err
		}
		err = sqlDrvr.DropTable(rc.Context, dbase.DB(), tblH.tbl, false)
		if err != nil {
			return err
		}

		fmt.Fprintf(rc.Out, "Dropped table %s.%s\n", tblH.src.Handle, tblH.tbl)
	}

	return nil
}

// parseTableHandleArgs parses args of the form:
//
//  @HANDLE1.TABLE1 .TABLE2 .TABLE3 @HANDLE2.TABLE4 .TABLEN
//
// It returns a slice of tblHandle, one for each arg. If an arg
// does not have a HANDLE, the active src is assumed: it's an error
// if no active src. It is also an error if len(args) is zero.
func parseTableHandleArgs(dp driver.Provider, srcs *source.Set, args []string) ([]tblHandle, error) {
	if len(args) == 0 {
		return nil, errz.New(msgInvalidArgs)
	}

	var tblHandles []tblHandle
	activeSrc := srcs.Active()

	// We iterate over the args several times, because we want
	// to present error checks consistently.
	for _, arg := range args {
		handle, tbl, err := source.ParseTableHandle(arg)
		if err != nil {
			return nil, err
		}

		tblHandles = append(tblHandles, tblHandle{
			handle: handle,
			tbl:    tbl,
		})
	}

	for i := range tblHandles {
		if tblHandles[i].tbl == "" {
			return nil, errz.Errorf("arg[%d] %q doesn't specify a table", i, args[i])
		}

		if tblHandles[i].handle == "" {
			// It's a table name without a handle, so we use the active src
			if activeSrc == nil {
				return nil, errz.Errorf("arg[%d] %q doesn't specify a handle and there's no active source",
					i, args[i])
			}

			tblHandles[i].handle = activeSrc.Handle
		}

		src, err := srcs.Get(tblHandles[i].handle)
		if err != nil {
			return nil, err
		}

		drvr, err := dp.DriverFor(src.Type)
		if err != nil {
			return nil, err
		}

		tblHandles[i].src = src
		tblHandles[i].drvr = drvr
	}

	return tblHandles, nil
}

// tblHandle represents a @HANDLE.TABLE, with the handle's associated
// src and driver.
type tblHandle struct {
	handle string
	tbl    string
	src    *source.Source
	drvr   driver.Driver
}