package actions

import (
	"errors"
	"io"
	"log"
	"maps"
	"regexp"
	"slices"

	"github.com/hymkor/exregexp-go"
	"tomatentum.net/svg-templater/internal/database"
	"tomatentum.net/svg-templater/pkg/svg"
)

type TemplateParameters struct {
	Id   string
	Keys map[string]string
}

func Template(r *TemplateParameters) ([]byte, error) {
	mapkeys := slices.Collect(maps.Keys(r.Keys))
	ok, err := verifyTemplate(r.Id, mapkeys)
	if err != nil {
		return nil, err
	}
	if !ok {
		return nil, errors.New("Template does not exist.")
	}
	log.Printf("Replacing keys of %s template\n", r.Id)

	reader, err := svg.Storage.Get(r.Id)
	if err != nil {
		return nil, err
	}
	defer reader.Close()
	svgblob, err := io.ReadAll(reader)
	if err != nil {
		return nil, err
	}
	replaceAll(&svgblob, r.Keys)
	log.Printf("Finished replacing keys of %s template\n", r.Id)
	return svgblob, nil
}

func replaceAll(svgblob *[]byte, keys map[string]string) {
	regex := regexp.MustCompile(svg.KeyRegex)
	*svgblob = []byte(exregexp.ReplaceAllStringSubmatchFunc(regex, string(*svgblob), func(s []string) string {
		log.Printf("Replacing key %s with %s\n", s[1], keys[s[1]])
		return keys[s[1]]
	}))
}

func verifyTemplate(id string, keys []string) (bool, error) {
	data, err := database.GetSpecificSVG(id)
	if err != nil {
		return false, err
	}

	for _, key := range data.TemplateKeys {
		if !slices.Contains(keys, key) {
			return false, nil
		}
	}
	return true, nil
}