package config

import (
	"os"
	"path/filepath"
	"strconv"
	"strings"
)

// Config 全局配置，从环境变量读取（带默认值）。
// system_config 表中的值在运行时覆盖对应字段（见 service）。
type Config struct {
	Port         string
	DBPath       string // SQLite 文件路径
	JWTSecret    string
	JWTExpireMin int

	LLMBaseURL string
	LLMAPIKey  string
	LLMModel   string
	EmbedModel string

	KnowledgeServiceURL string
	KnowledgeIndexDir   string

	KBDataDir          string
	KnowledgeSourceDir string

	// 定期备份。SQLite 是单文件、又没有任何外部主从，坏一份就是全丢，
	// 所以默认开着：启动补一次，之后每 BackupIntervalHours 小时一次，保留最近 N 份。
	BackupEnabled       bool
	BackupDir           string
	BackupKeep          int
	BackupIntervalHours int

	FileMaxDoc     int64
	FileMaxVideo   int64
	ChunkThreshold int64

	LibreOfficeBin string
	PdftotextBin   string

	KingdeeBaseURL    string
	KingdeeAccountID  string
	KingdeeUsername   string
	KingdeePassword   string
	KingdeeLCID       int
	KingdeeTimeoutSec int
}

// Load 读取环境变量构造配置。缺失的用默认值（部署时通过 .env / systemd 注入）。
func Load() *Config {
	baseDir := backendBaseDir()

	return &Config{
		Port:         getenv("PORT", "8080"),
		DBPath:       getenv("DB_PATH", filepath.Join(baseDir, "data", "eai_agentplatform.db")),
		JWTSecret:    getenv("JWT_SECRET", "change-this-to-a-strong-secret-in-production"),
		JWTExpireMin: getenvInt("JWT_EXPIRE_MINUTES", 480),

		LLMBaseURL: getenv("LLM_BASE_URL", "http://127.0.0.1:11434/v1"),
		LLMAPIKey:  getenv("LLM_API_KEY", "ollama"),
		LLMModel:   getenv("LLM_MODEL", "qwen2.5:7b"),
		EmbedModel: getenv("EMBED_MODEL", "bge-m3"),

		KnowledgeServiceURL: getenv("KNOWLEDGE_SERVICE_URL", "http://127.0.0.1:10233"),
		KnowledgeIndexDir:   getenv("KNOWLEDGE_INDEX_DIR", filepath.Join(baseDir, "data", "faiss")),

		KBDataDir:          getenv("KB_DATA_DIR", filepath.Join(baseDir, "data", "kb_data")),
		KnowledgeSourceDir: getenv("KNOWLEDGE_SOURCE_DIR", filepath.Join(baseDir, "knowledge_source")),

		// 备份目录必须落在 data/ 下：systemd 单元是 ProtectSystem=strict，
		// 只有 data/ 可写（ReadWritePaths），换到别处会静默失败。
		BackupEnabled:       getenvBool("BACKUP_ENABLED", true),
		BackupDir:           getenv("BACKUP_DIR", filepath.Join(baseDir, "data", "backups")),
		BackupKeep:          getenvInt("BACKUP_KEEP", 7),
		BackupIntervalHours: getenvInt("BACKUP_INTERVAL_HOURS", 24),

		FileMaxDoc:     getenvInt64("FILE_MAX_SIZE_DOC", 209715200),
		FileMaxVideo:   getenvInt64("FILE_MAX_SIZE_VIDEO", 2147483648),
		ChunkThreshold: getenvInt64("CHUNK_THRESHOLD", 104857600),

		LibreOfficeBin: getenv("LIBREOFFICE_BIN", "libreoffice"),
		PdftotextBin:   getenv("PDFTOTEXT_BIN", "pdftotext"),

		KingdeeBaseURL:    getenv("KINGDEE_BASE_URL", ""),
		KingdeeAccountID:  getenv("KINGDEE_ACCOUNT_ID", ""),
		KingdeeUsername:   getenv("KINGDEE_USERNAME", ""),
		KingdeePassword:   getenv("KINGDEE_PASSWORD", ""),
		KingdeeLCID:       getenvInt("KINGDEE_LCID", 2052),
		KingdeeTimeoutSec: getenvInt("KINGDEE_TIMEOUT_SEC", 15),
	}
}

func backendBaseDir() string {
	if exe, err := os.Executable(); err == nil && exe != "" {
		return filepath.Clean(filepath.Join(filepath.Dir(exe), ".."))
	}
	if wd, err := os.Getwd(); err == nil && wd != "" {
		return wd
	}
	return "."
}

func getenv(key, def string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return def
}

// getenvBool 只认显式的假值，其余（含没设）都算真 —— 默认开着的东西，
// 不该因为写了个看不懂的值就悄悄关掉。
func getenvBool(key string, def bool) bool {
	v := strings.ToLower(strings.TrimSpace(os.Getenv(key)))
	switch v {
	case "":
		return def
	case "0", "false", "no", "off":
		return false
	default:
		return true
	}
}

func getenvInt(key string, def int) int {
	if v := os.Getenv(key); v != "" {
		if n, err := strconv.Atoi(v); err == nil {
			return n
		}
	}
	return def
}

func getenvInt64(key string, def int64) int64 {
	if v := os.Getenv(key); v != "" {
		if n, err := strconv.ParseInt(v, 10, 64); err == nil {
			return n
		}
	}
	return def
}