package server

import (
	"fmt"
	"github.com/siddontang/ledisdb/ledis"
	"strconv"
	"strings"
)

type CommandFunc func(c *client) error

var regCmds = map[string]CommandFunc{}

func register(name string, f CommandFunc) {
	if _, ok := regCmds[strings.ToLower(name)]; ok {
		panic(fmt.Sprintf("%s has been registered", name))
	}

	regCmds[name] = f
}

func pingCommand(c *client) error {
	c.resp.writeStatus(PONG)
	return nil
}

func echoCommand(c *client) error {
	if len(c.args) != 1 {
		return ErrCmdParams
	}

	c.resp.writeBulk(c.args[0])
	return nil
}

func selectCommand(c *client) error {
	if len(c.args) != 1 {
		return ErrCmdParams
	}

	if index, err := strconv.Atoi(ledis.String(c.args[0])); err != nil {
		return err
	} else {
		if c.db.IsInMulti() {
			if err := c.script.Select(index); err != nil {
				return err
			} else {
				c.db = c.script.DB
			}
		} else {
			if db, err := c.ldb.Select(index); err != nil {
				return err
			} else {
				c.db = db
			}
		}
		c.resp.writeStatus(OK)
	}

	return nil
}

func infoCommand(c *client) error {
	if len(c.args) > 1 {
		return ErrSyntax
	}
	var section string
	if len(c.args) == 1 {
		section = strings.ToLower(ledis.String(c.args[0]))
	}

	buf := c.app.info.Dump(section)
	c.resp.writeBulk(buf)

	return nil
}

func flushallCommand(c *client) error {
	err := c.ldb.FlushAll()
	if err != nil {
		return err
	}

	c.resp.writeStatus(OK)
	return nil
}

func flushdbCommand(c *client) error {
	_, err := c.db.FlushAll()
	if err != nil {
		return err
	}

	c.resp.writeStatus(OK)
	return nil
}

func init() {
	register("ping", pingCommand)
	register("echo", echoCommand)
	register("select", selectCommand)
	register("info", infoCommand)
	register("flushall", flushallCommand)
	register("flushdb", flushdbCommand)
}