package config

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"git.apinb.com/bsm-sdk/core/types"
	"gopkg.in/yaml.v3"
)

// Config retains the legacy delivery YAML shape so existing deployments continue to work.
// Cache and Pulsar are deprecated and intentionally ignored because the service never used them.
type Config struct {
	Name      string              `yaml:"Name"`
	ListenOn  string              `yaml:"ListenOn"`
	DSN       string              `yaml:"Dsn"`
	Cache     string              `yaml:"Cache"`
	Anonymous types.AnonymousConf `yaml:"Anonymous"`
	Pulsar    types.PulsarConf    `yaml:"Pulsar"`
}

func Load(serviceKey string) (Config, error) {
	mode := strings.ToLower(envOr("BlocksMesh_RuntimeMode", "dev"))
	prefix := envOr("BlocksMesh_Prefix", ".")
	workspace := envOr("BlocksMesh_Workspace", "def")
	path := filepath.Join(prefix, "etc", fmt.Sprintf("%s_%s.yaml", serviceKey, mode))

	data, err := os.ReadFile(path)
	if err != nil {
		return Config{}, fmt.Errorf("read config %s: %w", path, err)
	}
	replacer := strings.NewReplacer(
		"{ServiceKey}", serviceKey,
		"{Workspace}", workspace,
		"{RuntimeMode}", mode,
	)
	var cfg Config
	if err := yaml.Unmarshal([]byte(os.ExpandEnv(replacer.Replace(string(data)))), &cfg); err != nil {
		return Config{}, fmt.Errorf("parse config %s: %w", path, err)
	}
	if cfg.ListenOn == "" {
		return Config{}, fmt.Errorf("ListenOn is required in %s", path)
	}
	return cfg, nil
}

func envOr(key, fallback string) string {
	if value := os.Getenv(key); value != "" {
		return value
	}
	return fallback
}