package main

import (
	"fmt"
)

type Rewrite struct {
	Domain string `yaml:"domain" json:"domain"`
	Answer string `yaml:"answer" json:"answer"`
}

func MergeRewrites(existing, desired []Rewrite) []Rewrite {
	existingMap := make(map[string]string)
	for _, r := range existing {
		existingMap[r.Domain] = r.Answer
	}

	desiredMap := make(map[string]string)
	for _, r := range desired {
		desiredMap[r.Domain] = r.Answer
	}

	updated := make([]Rewrite, 0)

	// Add or update
	for domain, ip := range desiredMap {
		if existingIP, found := existingMap[domain]; found {
			if existingIP != ip {
				fmt.Printf("Ändere %s: %s -> %s\n", domain, existingIP, ip)
			}
		} else {
			fmt.Printf("Füge hinzu: %s -> %s\n", domain, ip)
		}
		updated = append(updated, Rewrite{Domain: domain, Answer: ip})
	}

	// Delete outdated
	for domain, ip := range existingMap {
		if _, ok := desiredMap[domain]; !ok {
			fmt.Printf("Lösche: %s : %s\n", domain, ip)
		}
	}

	return updated
}

func (c *AdGuardClient) ApplyRewrites(desired []Rewrite) error {
	existing, err := c.GetRewrites()
	if err != nil {
		return err
	}

	existingMap := make(map[string]string)
	for _, r := range existing {
		existingMap[r.Domain] = r.Answer
	}

	desiredMap := make(map[string]string)
	for _, r := range desired {
		desiredMap[r.Domain] = r.Answer
	}

	for domain, ip := range desiredMap {
		if existingIP, ok := existingMap[domain]; ok {
			if existingIP != ip {
				if err := c.UpdateRewrite(Rewrite{Domain: domain, Answer: existingIP}, Rewrite{Domain: domain, Answer: ip}); err != nil {
					return err
				}
			}
		} else {
			if err := c.AddRewrite(Rewrite{Domain: domain, Answer: ip}); err != nil {
				return err
			}
		}
	}

	for domain, ip := range existingMap {
		if _, ok := desiredMap[domain]; !ok {
			if err := c.DeleteRewrite(Rewrite{Domain: domain, Answer: ip}); err != nil {
				return err
			}
		}
	}

	return nil
}