package controllers

import (
	"fmt"
	"net/http"
	"regexp"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/yxzzy-wtf/gin-gonic-prepack/util"
)

type rule struct {
	duration time.Duration
	limit    int
}

type bucket struct {
	rules  *map[string]rule
	access map[string]int
}

func (b *bucket) take(resource string) bool {
	r, ex := (*b.rules)[resource]
	if !ex {
		// does not exist, forced to try match on regex?
		regexMatched := false
		for attemptMatch, attemptRes := range *b.rules {
			match, _ := regexp.MatchString("^"+attemptMatch+"$", resource)
			if match {
				resource = attemptMatch
				r = attemptRes
				regexMatched = true
				break
			}
		}

		if !regexMatched {
			// Default to Global
			fmt.Printf("defaulting %v to global\n", resource)
			resource = ""
			r = (*b.rules)[resource]
		}
	}
	max := r.limit
	duration := r.duration

	remaining, ex := b.access[resource]
	if !ex {
		b.access[resource] = max
		remaining = max
	}

	if remaining > 0 {
		remaining = remaining - 1
		b.access[resource] = remaining

		go func(b *bucket, res string, d time.Duration) {
			time.Sleep(d)
			b.access[resource] = b.access[resource] + 1
		}(b, resource, duration)

		return true
	}

	return false
}

type megabucket struct {
	buckets map[string]bucket
	rules   map[string]rule
}

func (m *megabucket) take(signature string, resource string) bool {
	b, ex := m.buckets[signature]
	if !ex {
		b = bucket{
			rules:  &m.rules,
			access: map[string]int{},
		}
		m.buckets[signature] = b
	}

	return b.take(resource)
}

var unauthed = megabucket{
	buckets: map[string]bucket{},
	rules: map[string]rule{
		"*": {duration: time.Second * 10, limit: 20},
	},
}

func UnauthRateLimit() gin.HandlerFunc {
	return func(c *gin.Context) {
		ip := c.ClientIP()

		if !unauthed.take(ip, "") {
			c.AbortWithStatus(http.StatusTooManyRequests)
			return
		}
	}
}

var authed = megabucket{
	buckets: map[string]bucket{},
	rules: map[string]rule{
		"*": {duration: time.Second * 10, limit: 5},
	},
}

func AuthedRateLimit() gin.HandlerFunc {
	return func(c *gin.Context) {
		pif, exists := c.Get("principal")
		p := pif.(util.PrincipalInfo)
		if !exists {
			c.AbortWithStatus(http.StatusUnauthorized)
			return
		}

		if !authed.take(p.Uid.String(), c.FullPath()) {
			c.AbortWithStatus(http.StatusTooManyRequests)
			return
		}
	}
}