package config

import (
	"bufio"
	"log"
	"os"
	"path/filepath"
	"strings"

	"github.com/spf13/viper"
)

type Config struct {
	Server struct {
		IP          string
		Port        int
		AccessToken string
	}
	Log struct {
		Level   string
		LogPath string `mapstructure:"logPath"`
	} `mapstructure:"log"`
	Chat struct {
		ApiKey            string  `mapstructure:"api_key"`
		BaseUrl           string  `mapstructure:"base_url"`
		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"`
	}
	Mysql struct {
		DSN         string
		MaxLifeTime int
		MaxOpenConn int
		MaxIdleConn int
	}
	Redis struct {
		Host string
		Port int
		Pwd  string `mapstructure:"pwd"`
	}
	DependOn struct {
		Sensitive struct {
			Address     string
			AccessToken string
		}
		Keywords struct {
			Address     string
			AccessToken string
		}
		Tokenizer struct {
			Address string
		}
	}
	Vector struct {
		Provider  string
		Threshold float32
		Tencent   struct {
			Url                string
			Username           string
			Pwd                string
			Database           string
			Timeout            int
			MaxIdleConnPerHost int
			ReadConsistency    string
			IdleConnTimeout    int
		}
		Pgvector struct {
			DSN         string `mapstructure:"dsn"`
			Table       string `mapstructure:"table"`
			Dimensions  int    `mapstructure:"dimensions"`
			MaxLifeTime int    `mapstructure:"maxLifeTime"`
			MaxOpenConn int    `mapstructure:"maxOpenConn"`
			MaxIdleConn int    `mapstructure:"maxIdleConn"`
		}
	}
	Embedding struct {
		Provider string
		BaseUrl  string `mapstructure:"base_url"`
		ApiKey   string `mapstructure:"api_key"`
		Model    string `mapstructure:"model"`
		Timeout  int
	}
	VectorDB struct {
		Url                string
		Username           string
		Pwd                string
		Database           string
		Timeout            int
		MaxIdleConnPerHost int
		ReadConsistency    string
		IdleConnTimeout    int
	}
}

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)

}

func GetConfig() *Config {
	return conf
}

func normalizeConfig(conf *Config) {
	if conf.Vector.Provider == "" {
		conf.Vector.Provider = "tencent"
	}
	if conf.Vector.Threshold == 0 {
		conf.Vector.Threshold = 0.99
	}

	// Backfill the new vector.tencent block from the legacy vectorDB config.
	if conf.Vector.Tencent.Url == "" {
		conf.Vector.Tencent.Url = conf.VectorDB.Url
	}
	if conf.Vector.Tencent.Username == "" {
		conf.Vector.Tencent.Username = conf.VectorDB.Username
	}
	if conf.Vector.Tencent.Pwd == "" {
		conf.Vector.Tencent.Pwd = conf.VectorDB.Pwd
	}
	if conf.Vector.Tencent.Database == "" {
		conf.Vector.Tencent.Database = conf.VectorDB.Database
	}
	if conf.Vector.Tencent.Timeout == 0 {
		conf.Vector.Tencent.Timeout = conf.VectorDB.Timeout
	}
	if conf.Vector.Tencent.MaxIdleConnPerHost == 0 {
		conf.Vector.Tencent.MaxIdleConnPerHost = conf.VectorDB.MaxIdleConnPerHost
	}
	if conf.Vector.Tencent.ReadConsistency == "" {
		conf.Vector.Tencent.ReadConsistency = conf.VectorDB.ReadConsistency
	}
	if conf.Vector.Tencent.IdleConnTimeout == 0 {
		conf.Vector.Tencent.IdleConnTimeout = conf.VectorDB.IdleConnTimeout
	}

	if conf.Embedding.Provider == "" {
		conf.Embedding.Provider = "openai-compatible"
	}
	if conf.Embedding.BaseUrl == "" {
		conf.Embedding.BaseUrl = conf.Chat.BaseUrl
	}
	if conf.Embedding.ApiKey == "" {
		conf.Embedding.ApiKey = conf.Chat.ApiKey
	}
	if conf.Embedding.Timeout == 0 {
		conf.Embedding.Timeout = 10
	}
	overrideChatFromEnv(conf)
	overrideEmbeddingFromEnv(conf)
}

func overrideChatFromEnv(conf *Config) {
	if value := os.Getenv("AI_CHAT_OPENAI_BASE_URL"); value != "" {
		conf.Chat.BaseUrl = value
	} else if value := os.Getenv("OPENAI_BASE_URL"); value != "" {
		conf.Chat.BaseUrl = value
	}

	if value := os.Getenv("AI_CHAT_OPENAI_MODEL"); value != "" {
		conf.Chat.Model = value
	} else if value := os.Getenv("OPENAI_MODEL"); value != "" {
		conf.Chat.Model = value
	}

	if value := os.Getenv("AI_CHAT_OPENAI_API_KEY"); value != "" {
		conf.Chat.ApiKey = value
		return
	}
	if value := os.Getenv("OPENAI_API_KEY"); value != "" {
		conf.Chat.ApiKey = value
		return
	}
	if value := os.Getenv("MOONSHOT_API_KEY"); value != "" {
		conf.Chat.ApiKey = value
	}
}

func overrideEmbeddingFromEnv(conf *Config) {
	if value := os.Getenv("AI_CHAT_EMBEDDING_BASE_URL"); value != "" {
		conf.Embedding.BaseUrl = value
	}
	if value := os.Getenv("AI_CHAT_EMBEDDING_MODEL"); value != "" {
		conf.Embedding.Model = value
	}
	if value := os.Getenv("AI_CHAT_EMBEDDING_API_KEY"); value != "" {
		conf.Embedding.ApiKey = value
		return
	}
	if value := os.Getenv("ZAI_API_KEY"); value != "" {
		conf.Embedding.ApiKey = value
	}
}

func loadProjectDotEnv(configFilePath string) {
	projectRoot := filepath.Dir(filepath.Dir(configFilePath))
	loadDotEnvFile(filepath.Join(projectRoot, ".env"))
}

func loadDotEnvFile(path string) {
	file, err := os.Open(path)
	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)
		value = strings.Trim(value, `"'`)
		if key == "" {
			continue
		}
		if _, exists := os.LookupEnv(key); exists {
			continue
		}
		_ = os.Setenv(key, value)
	}
}