package hlog

import (
	"git.haelnorr.com/h/golib/env"
	"github.com/pkg/errors"
)

// Config holds the configuration settings for the logger.
// It can be populated from environment variables using ConfigFromEnv
// or created programmatically.
type Config struct {
	LogLevel    Level  `ezconf:"LOG_LEVEL,description:Log level for the logger - trace debug info warn error fatal panic,default:info"`
	LogOutput   string `ezconf:"LOG_OUTPUT,description:Output destination for logs - console file or both,default:console"`
	LogDir      string `ezconf:"LOG_DIR,description:Directory path for log files,required:when LOG_OUTPUT is file or both"`
	LogFileName string `ezconf:"LOG_FILE_NAME,description:Name of the log file,required:when LOG_OUTPUT is file or both"`
	LogAppend   bool   `ezconf:"LOG_APPEND,description:Append to existing log file or overwrite,default:true"`
}

// ConfigFromEnv loads logger configuration from environment variables.
//
// Environment variables:
//   - LOG_LEVEL: Log level (trace, debug, info, warn, error, fatal, panic) - default: info
//   - LOG_OUTPUT: Output destination (console, file, both) - default: console
//   - LOG_DIR: Directory for log files (required when LOG_OUTPUT is "file" or "both")
//
// Returns an error if:
//   - LOG_LEVEL contains an invalid value
//   - LOG_OUTPUT contains an invalid value
//   - LogDir or LogFileName is not set and file logging is enabled
func ConfigFromEnv() (*Config, error) {
	logLevel, err := LogLevel(env.String("LOG_LEVEL", "info"))
	if err != nil {
		return nil, errors.Wrap(err, "LogLevel")
	}
	logOutput := env.String("LOG_OUTPUT", "console")
	if logOutput != "both" && logOutput != "console" && logOutput != "file" {
		return nil, errors.Errorf("Invalid LOG_OUTPUT: %s", logOutput)
	}
	cfg := &Config{
		LogLevel:    logLevel,
		LogOutput:   logOutput,
		LogDir:      env.String("LOG_DIR", ""),
		LogFileName: env.String("LOG_FILE_NAME", ""),
		LogAppend:   env.Bool("LOG_APPEND", true),
	}
	if cfg.LogOutput != "console" {
		if cfg.LogDir == "" {
			return nil, errors.New("LOG_DIR not set but file logging enabled")
		}
		if cfg.LogFileName == "" {
			return nil, errors.New("LOG_FILE_NAME not set but file logging enabled")
		}
	}
	return cfg, nil
}