package budget

import (
	"encoding/json"
	"os"
	"path/filepath"
)

type paths struct {
	config string
	units  string
	state  string
}

func homePaths(home string) paths {
	return paths{
		config: filepath.Join(home, ".config/budget/profiles.toml"),
		units:  filepath.Join(home, ".config/systemd/user"),
		state:  filepath.Join(home, ".local/state/budget"),
	}
}

func writeFiles(p paths, files map[string]string) error {
	if err := os.MkdirAll(p.state, 0755); err != nil {
		return err
	}
	manifest := filepath.Join(p.state, "files.json")
	previous := []string{}
	data, err := os.ReadFile(manifest)
	if err != nil && !os.IsNotExist(err) {
		return err
	}
	if err == nil {
		if err := json.Unmarshal(data, &previous); err != nil {
			return err
		}
	}
	for _, relative := range previous {
		if _, keep := files[relative]; !keep {
			if err := os.Remove(filepath.Join(p.units, relative)); err != nil && !os.IsNotExist(err) {
				return err
			}
		}
	}
	for _, relative := range keys(files) {
		target := filepath.Join(p.units, relative)
		if err := os.MkdirAll(filepath.Dir(target), 0755); err != nil {
			return err
		}
		if err := os.WriteFile(target, []byte(files[relative]), 0644); err != nil {
			return err
		}
	}
	data, err = json.MarshalIndent(keys(files), "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(manifest, append(data, '\n'), 0644)
}