package main

import (
	"fmt"
	e "git.xdrm.io/go/xb-api/err"
	i "git.xdrm.io/go/xb-api/implement"
	"github.com/go-redis/redis"
)

const NONCE = "go-tiny-url"

type db redis.Client

// Returns a connected client to dataset
func connect() *db {
	cli := redis.NewClient(&redis.Options{
		Addr:     "127.0.0.1:6379",
		Password: "",
		DB:       0,
	})

	if _, err := cli.Ping().Result(); err != nil {
		return nil
	}

	return (*db)(cli)
}

// returns value from key (nil if nothing)
func (c *db) get(key string) []byte {

	// 1. Try to get
	if val, err := c.Get(fmt.Sprintf("%s:%s", NONCE, key)).Result(); err != nil {
		// 2. nil if nothing found
		return nil
	} else {
		// 3. return if found
		return []byte(val)
	}

}

// stores a value for a key (success state in return)
func (c *db) set(key string, value string) bool {

	// 1. Try to set
	if c.Set(fmt.Sprintf("%s:%s", NONCE, key), value, 0).Err() != nil {
		// 2. failure
		return false
	}

	// 3. success
	return true

}

// deletes the value for a key (success state in return)
func (c *db) del(key string) bool {

	// 1. Try to set
	if c.Del(fmt.Sprintf("%s:%s", NONCE, key)).Err() != nil {
		// 2. failure
		return false
	}

	// 3. success
	return true

}

// Redirects to an url from a key
func Get(d i.Arguments, r *i.Response) i.Response {

	/* (1) Init redis connection */
	cli := connect()
	if cli == nil {
		r.Err = e.Failure
		return *r
	}

	/* (2) Extract api input */
	key, ok := d["url"].(string)

	if !ok {
		r.Err = e.InvalidParam
		r.Err.BindArgument("url")
		return *r
	}

	/* (3) Check if match for this key */
	val := cli.get(key)
	if val == nil {
		r.Err = e.NoMatchFound
		return *r
	}

	/* (4) Redirect to value */
	r.Set("_REDIRECT_", string(val))
	r.Err = e.Success
	return *r
}

// Stores a new tinyurl/fullurl combination
func Post(d i.Arguments, r *i.Response) i.Response {
	/* (1) Init redis connection */
	cli := connect()
	if cli == nil {
		r.Err = e.Failure
		return *r
	}

	/* (2) Extract api input */
	target, ok1 := d["target"].(string)
	url, ok2 := d["url"].(string)

	if !ok1 || !ok2 {
		r.Err = e.InvalidParam
		return *r
	}

	/* (3) Check if key already used */
	if cli.get(url) != nil {
		r.Err = e.AlreadyExists
		return *r
	}

	/* (4) Store */
	if !cli.set(url, target) {
		r.Err = e.Failure
		return *r
	}

	r.Err = e.Success
	return *r
}

// Overrides a existing tinyurl with new target
func Put(d i.Arguments, r *i.Response) i.Response {

	/* (1) Init redis connection */
	cli := connect()
	if cli == nil {
		r.Err = e.Failure
		return *r
	}

	/* (2) Extract api input */
	target, ok1 := d["target"].(string)
	url, ok2 := d["url"].(string)

	if !ok1 || !ok2 {
		r.Err = e.InvalidParam
		return *r
	}

	/* (3) Check if key already used */
	if cli.get(url) == nil {
		r.Err = e.NoMatchFound
		return *r
	}

	/* (4) Update */
	if !cli.set(url, target) {
		r.Err = e.Failure
		return *r
	}

	r.Err = e.Success
	return *r
}

// Deletes an existing tinyurl
func Delete(d i.Arguments, r *i.Response) i.Response {

	/* (1) Init redis connection */
	cli := connect()
	if cli == nil {
		r.Err = e.Failure
		return *r
	}

	/* (2) Extract api input */
	url, ok := d["url"].(string)

	if !ok {
		r.Err = e.InvalidParam
		return *r
	}

	/* (3) Check if key already used */
	if cli.get(url) == nil {
		r.Err = e.NoMatchFound
		return *r
	}

	/* (4) Delete */
	if !cli.del(url) {
		r.Err = e.Failure
		return *r
	}

	r.Err = e.Success
	return *r
}