package patches

import (
	"fmt"
	"os"
	"regexp"

	"github.com/sirupsen/logrus"
	"gopkg.in/yaml.v2"
)

type Patch struct {
	Name    string
	Targets []string
	Before  string
	After   string
}

type Patches []*Patch

func NewPatchFromFile(filePath string) (*Patch, error){
	var patch Patch
	logrus.Infof("reading a new patch file: %s", filePath)
	patchFile, err := os.ReadFile(filePath)
	if err != nil {
		return nil, err 
	}

	if err := yaml.Unmarshal(patchFile, &patch); err != nil {
		return nil, err
	}
	return &patch, nil
}

func(p *Patch) Apply(chartDir string) error {
	logrus.Infof("Applying patch: %s", p.Name)
	if len(p.Before) > 0 {
		beforeCompiled, err := regexp.Compile(p.Before)
		if err != nil {
			return err
		}

		for _, target := range p.Targets {
			fullTarget := fmt.Sprintf("%s/%s", chartDir, target)
			file, err := os.ReadFile(fullTarget)
			if err != nil {
				return err
			}
			newfile := beforeCompiled.ReplaceAll(file, []byte(p.After))
			err = os.WriteFile(fullTarget, newfile, os.ModePerm)
			if err != nil {
				return err
			}	
		}
	} else {
		for _, target := range p.Targets {
			fullTarget := fmt.Sprintf("%s/%s", chartDir, target)
    	f, err := os.OpenFile(fullTarget, os.O_APPEND|os.O_CREATE|os.O_WRONLY, os.ModePerm)
	    if err != nil {
	        return err
	    }
			defer f.Close()
	    if _, err := f.Write([]byte(p.After + "\n")); err != nil {
				return err
	    }
	    if err := f.Close(); err != nil {
        return err
  	  }
		}
	}
	return nil
}