package config

import (
	"bufio"
	"github.com/spf13/viper"
	"log"
	"os"
	"path/filepath"
	"strconv"
	"strings"
)

type Config struct {
	Http struct {
		IP   string
		Port int
	}
	BasicAuthUser     string `mapstructure:"basic_auth_user"`
	BasicAuthPassword string `mapstructure:"basic_auth_password"`
	FrontendPath      string `mapstructure:"frontend_path"`
	Log struct {
		Level   string
		LogPath string `mapstructure:"logPath"`
	} `mapstructure:"log"`
	Chat struct {
		Model             string  `mapstructure:"model"`
		MaxTokens         int     `mapstructure:"max_tokens"`
		Temperature       float32 `mapstructure:"temperature"`
		TopP              float32 `mapstructure:"top_p"`
		PresencePenalty   float32 `mapstructure:"presence_penalty"`
		FrequencyPenalty  float32 `mapstructure:"frequency_penalty"`
		BotDesc           string  `mapstructure:"bot_desc"`
		MinResponseTokens int     `mapstructure:"min_response_tokens"`
		ContextTTL        int     `mapstructure:"context_ttl"`
		ContextLen        int     `mapstructure:"context_len"`
	}
	DependOn struct {
		AiChatService struct {
			Address     string
			AccessToken string
		} `mapstructure:"ai-chat-service"`
	}
}

var conf *Config

func InitConfig(filePath string, typ ...string) {
	loadProjectDotEnv(filePath)
	v := viper.New()
	v.SetConfigFile(filePath)
	if len(typ) > 0 {
		v.SetConfigType(typ[0])
	}
	err := v.ReadInConfig()
	if err != nil {
		log.Fatal(err)
	}
	conf = &Config{}
	err = v.Unmarshal(conf)
	if err != nil {
		log.Fatal(err)
	}
	normalizeConfig(conf)
	overrideConfigFromEnv(conf)

}

func GetConfig() *Config {
	return conf
}

func normalizeConfig(conf *Config) {
	if conf.Http.IP == "" {
		conf.Http.IP = "0.0.0.0"
	}
	if conf.Http.Port == 0 {
		conf.Http.Port = 7080
	}
	if conf.FrontendPath == "" {
		conf.FrontendPath = "www"
	}
	if conf.Chat.Model == "" {
		conf.Chat.Model = "kimi-k2.5"
	}
	if conf.Chat.MaxTokens == 0 {
		conf.Chat.MaxTokens = 4096
	}
	if conf.Chat.Temperature == 0 {
		conf.Chat.Temperature = 1.0
	}
	if conf.Chat.TopP == 0 {
		conf.Chat.TopP = 1.0
	}
	if conf.Chat.MinResponseTokens == 0 {
		conf.Chat.MinResponseTokens = 600
	}
	if conf.DependOn.AiChatService.Address == "" {
		conf.DependOn.AiChatService.Address = "localhost:50055"
	}
}

func overrideConfigFromEnv(conf *Config) {
	overrideString(&conf.Http.IP, os.Getenv("SERVER_HOST"))
	overrideInt(&conf.Http.Port, os.Getenv("SERVER_PORT"))
	overrideString(&conf.BasicAuthUser, os.Getenv("BASIC_AUTH_USER"))
	overrideString(&conf.BasicAuthPassword, os.Getenv("BASIC_AUTH_PASSWORD"))
	overrideString(&conf.FrontendPath, os.Getenv("FRONTEND_PATH"))
	overrideString(&conf.Chat.Model, os.Getenv("OPENAI_MODEL"))
	overrideInt(&conf.Chat.MaxTokens, os.Getenv("OPENAI_MAX_TOKENS"))
	overrideScaledFloat32(&conf.Chat.Temperature, os.Getenv("OPENAI_TEMPERATURE"))
	overrideScaledFloat32(&conf.Chat.PresencePenalty, os.Getenv("OPENAI_PRESENCE_PENALTY"))
	overrideScaledFloat32(&conf.Chat.FrequencyPenalty, os.Getenv("OPENAI_FREQUENCY_PENALTY"))
	overrideInt(&conf.Chat.MinResponseTokens, os.Getenv("CHAT_MIN_RESPONSE_TOKENS"))
	overrideString(&conf.DependOn.AiChatService.Address, firstNonEmpty(
		os.Getenv("AI_CHAT_SERVICE_ADDRESS"),
		os.Getenv("AI_CHAT_SERVICE_ADDR"),
	))
	overrideString(&conf.DependOn.AiChatService.AccessToken, os.Getenv("AI_CHAT_SERVICE_ACCESS_TOKEN"))
}

func loadProjectDotEnv(configFilePath string) {
	projectRoot := filepath.Dir(filepath.Dir(configFilePath))
	envPath := filepath.Join(projectRoot, ".env")
	file, err := os.Open(envPath)
	if err != nil {
		return
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		key, value, ok := strings.Cut(line, "=")
		if !ok {
			continue
		}
		key = strings.TrimSpace(key)
		value = strings.TrimSpace(value)
		if key == "" {
			continue
		}
		if _, exists := os.LookupEnv(key); exists {
			continue
		}
		_ = os.Setenv(key, value)
	}
}

func firstNonEmpty(values ...string) string {
	for _, value := range values {
		if strings.TrimSpace(value) != "" {
			return value
		}
	}
	return ""
}

func overrideString(target *string, value string) {
	if strings.TrimSpace(value) != "" {
		*target = strings.TrimSpace(value)
	}
}

func overrideInt(target *int, value string) {
	value = strings.TrimSpace(value)
	if value == "" {
		return
	}
	if parsed, err := strconv.Atoi(value); err == nil {
		*target = parsed
	}
}

func overrideScaledFloat32(target *float32, value string) {
	value = strings.TrimSpace(value)
	if value == "" {
		return
	}
	if parsed, err := strconv.ParseFloat(value, 32); err == nil {
		*target = float32(parsed / 100.0)
	}
}