/*
Copyright © 2026 Craig Williams <craig@avsdev.uk>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package config

import (
	"fmt"
	"log/slog"

	"github.com/joho/godotenv"
	"github.com/spf13/viper"
)

// Reads in dotenv file for configuration
func loadEnv() error {
	if err := godotenv.Load(); err != nil {
		return fmt.Errorf("invalid .env file: %w", err)
	}
	return nil
}

// Reads in config file and ENV variables if set to form a configuration.
func loadConfig(cfgFile string) error {
	if cfgFile != "" {
		// Use config file from the flag.
		viper.SetConfigFile(cfgFile)
	} else {
		// Search config in /etc or local directory.
		viper.AddConfigPath(EtcConfigPath)
		viper.AddConfigPath(".")

		viper.SetConfigName("config")
	}

	// Load default configuration
	LoadDefaultConfig()

	viper.SetEnvPrefix(EnvPrefix)
	viper.AutomaticEnv() // read in environment variables that match

	err := viper.ReadInConfig()
	if err != nil {
		if _, ok := err.(viper.ConfigFileNotFoundError); ok {
			// Indicates an explicitly set config file is not found or
			// that no config file was found in any search path
			slog.Warn("No config file found!")
		} else {
			// Config file was found but another error was produced
			return err
		}
	} else {
		// Config file found and successfully parsed
		slog.Info("Using config file: " + viper.ConfigFileUsed())
	}
	return nil
}

// Initilises environment file configuration and general app configuration
func Init(cfgFile string, conf *JobSearchConfig) error {
	if err := loadEnv(); err != nil {
		return err
	}
	if conf.Logging.LogLevel() <= slog.LevelDebug {
		printEnv()
	}

	if err := loadConfig(cfgFile); err != nil {
		return err
	}

	oldLogLevel := conf.Logging.Level
	LoadFromViper(conf)
	if ConfigLevelToLogLevel(oldLogLevel) < conf.Logging.LogLevel() {
		conf.Logging.Level = oldLogLevel
	}

	if conf.Logging.LogLevel() <= slog.LevelDebug {
		printLoadedConfig()
		printConfig(*conf)
	}

	return nil
}