package config

import (
	"crypto/rand"
	"encoding/hex"
	"os"
	"path/filepath"
	"strings"
)

type Config struct {
	Addr        string
	Driver      string // sqlite | postgres
	DSN         string
	AdminUser   string
	AdminPass   string
	SessionSec  string
	WebDist     string
	DataDir     string
	SiteURL     string
	InsecureDev bool
}

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

func Load() (*Config, error) {
	root := getenv("ONE_ROOT", "")
	if root == "" {
		if wd, err := os.Getwd(); err == nil {
			root = filepath.Dir(wd) // server/ -> repo root
		} else {
			root = "."
		}
	}

	c := &Config{
		Addr:       getenv("ONE_ADDR", ":8080"),
		Driver:     strings.ToLower(getenv("ONE_DB_DRIVER", "sqlite")),
		AdminUser:  getenv("ONE_ADMIN_USER", "admin"),
		AdminPass:  getenv("ONE_ADMIN_PASSWORD", "admin"),
		SessionSec: getenv("ONE_SECRET", ""),
		WebDist:    getenv("ONE_WEB_DIST", filepath.Join(root, "frontend", "dist")),
		DataDir:    getenv("ONE_DATA_DIR", filepath.Join(root, "data")),
		SiteURL:    getenv("ONE_SITE_URL", "http://localhost:8080"),
	}

	if c.Driver == "" {
		c.Driver = "sqlite"
	}
	if c.Driver != "sqlite" && c.Driver != "postgres" && c.Driver != "postgresql" {
		return nil, &badDriver{c.Driver}
	}
	if c.Driver == "postgresql" {
		c.Driver = "postgres"
	}

	if c.DSN = getenv("ONE_DB_DSN", ""); c.DSN == "" {
		if c.Driver == "sqlite" {
			c.DSN = filepath.Join(c.DataDir, "one.db")
		} else {
			c.DSN = "postgres://localhost/one?sslmode=disable"
		}
	}

	if c.SessionSec == "" {
		b := make([]byte, 32)
		if _, err := rand.Read(b); err != nil {
			return nil, err
		}
		c.SessionSec = hex.EncodeToString(b)
	}

	c.InsecureDev = os.Getenv("ONE_ADMIN_PASSWORD") == ""

	return c, nil
}

type badDriver struct{ d string }

func (e *badDriver) Error() string {
	return "unsupported ONE_DB_DRIVER: " + e.d + " (use sqlite or postgres)"
}