package config

import (
	"log/slog"
	"net/url"
	"os"
	"strings"
)

const (
	DefaultLocalGeneratedStorageDir = "data/static/generated"
	DefaultLocalUploadedStorageDir  = "data/static/uploaded"
)

type Config struct {
	AppEnv                          string
	HTTPAddr                        string
	DatabaseURL                     string
	IdentityMode                    string
	JWTSecret                       string
	ServerMainBaseURL               string
	ServerMainInternalToken         string
	PublicBaseURL                   string
	LocalGeneratedStorageDir        string
	LocalUploadedStorageDir         string
	TaskProgressCallbackEnabled     bool
	TaskProgressCallbackURL         string
	TaskProgressCallbackTimeoutMS   string
	TaskProgressCallbackMaxAttempts string
	CORSAllowedOrigin               string
	GlobalHTTPProxy                 string
	GlobalHTTPProxySource           string
	LogLevel                        slog.Level
}

func Load() Config {
	globalProxy := LoadGlobalHTTPProxyStatus()
	return Config{
		AppEnv:       env("APP_ENV", "development"),
		HTTPAddr:     env("HTTP_ADDR", ":8088"),
		DatabaseURL:  gatewayDatabaseURL(),
		IdentityMode: env("IDENTITY_MODE", "hybrid"),
		JWTSecret:    env("CONFIG_JWT_SECRET", "this is a very secret secret"),
		ServerMainBaseURL: strings.TrimRight(
			env("SERVER_MAIN_BASE_URL", "http://localhost:3000"),
			"/",
		),
		ServerMainInternalToken:     env("SERVER_MAIN_INTERNAL_TOKEN", ""),
		PublicBaseURL:               strings.TrimRight(env("AI_GATEWAY_PUBLIC_BASE_URL", env("PUBLIC_BASE_URL", "")), "/"),
		LocalGeneratedStorageDir:    env("AI_GATEWAY_GENERATED_STORAGE_DIR", env("LOCAL_GENERATED_STORAGE_DIR", env("AI_GATEWAY_STATIC_STORAGE_DIR", DefaultLocalGeneratedStorageDir))),
		LocalUploadedStorageDir:     env("AI_GATEWAY_UPLOADED_STORAGE_DIR", env("LOCAL_UPLOADED_STORAGE_DIR", DefaultLocalUploadedStorageDir)),
		TaskProgressCallbackEnabled: env("TASK_PROGRESS_CALLBACK_ENABLED", "true") == "true",
		TaskProgressCallbackURL: env("TASK_PROGRESS_CALLBACK_URL",
			strings.TrimRight(env("SERVER_MAIN_BASE_URL", "http://localhost:3000"), "/")+"/internal/platform/task-progress-callbacks",
		),
		TaskProgressCallbackTimeoutMS:   env("TASK_PROGRESS_CALLBACK_TIMEOUT_MS", "5000"),
		TaskProgressCallbackMaxAttempts: env("TASK_PROGRESS_CALLBACK_MAX_ATTEMPTS", "10"),
		CORSAllowedOrigin:               env("CORS_ALLOWED_ORIGIN", "http://localhost:5178,http://127.0.0.1:5178"),
		GlobalHTTPProxy:                 globalProxy.HTTPProxy,
		GlobalHTTPProxySource:           globalProxy.Source,
		LogLevel:                        logLevel(env("LOG_LEVEL", "info")),
	}
}

type GlobalHTTPProxyStatus struct {
	HTTPProxy string
	Source    string
}

func LoadGlobalHTTPProxyStatus() GlobalHTTPProxyStatus {
	for _, key := range []string{
		"AI_GATEWAY_GLOBAL_HTTP_PROXY",
		"GLOBAL_HTTP_PROXY",
		"HTTPS_PROXY",
		"https_proxy",
		"HTTP_PROXY",
		"http_proxy",
		"ALL_PROXY",
		"all_proxy",
	} {
		if value := envValue(key); value != "" {
			return GlobalHTTPProxyStatus{HTTPProxy: value, Source: key}
		}
	}
	return GlobalHTTPProxyStatus{}
}

func gatewayDatabaseURL() string {
	if value := envValue("AI_GATEWAY_DATABASE_URL"); value != "" {
		return normalizePostgresURL(value)
	}
	if value := envValue("DATABASE_URL"); value != "" {
		return normalizePostgresURL(value)
	}
	if memoryURL := envValue("MEMORY_DATABASE_URL"); memoryURL != "" {
		return normalizePostgresURL(withDatabase(memoryURL, env("AI_GATEWAY_DATABASE_NAME", "easyai_ai_gateway")))
	}
	return normalizePostgresURL("postgresql://easyai:easyai2025@localhost:5432/easyai_ai_gateway?sslmode=disable")
}

func normalizePostgresURL(raw string) string {
	parsed, err := url.Parse(raw)
	if err != nil {
		return raw
	}
	values := parsed.Query()
	schema := values.Get("schema")
	if schema == "" {
		return raw
	}
	values.Del("schema")
	if values.Get("search_path") == "" {
		values.Set("search_path", schema)
	}
	parsed.RawQuery = values.Encode()
	return parsed.String()
}

func withDatabase(raw string, databaseName string) string {
	parsed, err := url.Parse(raw)
	if err != nil || databaseName == "" {
		return raw
	}
	parsed.Path = "/" + databaseName
	return parsed.String()
}

func envValue(key string) string {
	return strings.TrimSpace(os.Getenv(key))
}

func env(key string, fallback string) string {
	if value := envValue(key); value != "" {
		return value
	}
	return fallback
}

func logLevel(value string) slog.Level {
	switch strings.ToLower(value) {
	case "debug":
		return slog.LevelDebug
	case "warn", "warning":
		return slog.LevelWarn
	case "error":
		return slog.LevelError
	default:
		return slog.LevelInfo
	}
}