package config

import (
	"fmt"
	"os"
	"regexp"

	"gopkg.in/yaml.v3"
)

// ProjectConfig represents ./aevs.yaml
type ProjectConfig struct {
	Project string   `yaml:"project"` // unique project identifier
	Files   []string `yaml:"files"`   // list of file paths to sync
}

// projectNameRegex validates project names (only a-z, 0-9, -, _)
var projectNameRegex = regexp.MustCompile(`^[a-z0-9_-]+$`)

// LoadProjectConfig loads a project config from the specified path
func LoadProjectConfig(path string) (*ProjectConfig, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}

	var cfg ProjectConfig
	if err := yaml.Unmarshal(data, &cfg); err != nil {
		return nil, err
	}

	// Validate project name
	if err := ValidateProjectName(cfg.Project); err != nil {
		return nil, err
	}

	return &cfg, nil
}

// SaveProjectConfig saves a project config to the specified path
func SaveProjectConfig(path string, cfg *ProjectConfig) error {
	// Validate project name before saving
	if err := ValidateProjectName(cfg.Project); err != nil {
		return err
	}

	// Marshal to YAML
	data, err := yaml.Marshal(cfg)
	if err != nil {
		return err
	}

	// Write file
	if err := os.WriteFile(path, data, 0644); err != nil {
		return err
	}

	return nil
}

// ValidateProjectName checks if the project name contains only a-z, 0-9, -, _
func ValidateProjectName(name string) error {
	if name == "" {
		return fmt.Errorf("project name cannot be empty")
	}

	if !projectNameRegex.MatchString(name) {
		return fmt.Errorf("invalid project name %q; use only a-z, 0-9, -, _", name)
	}

	return nil
}