// Package config loads daemon configuration from flags and environment
// variables (flags take precedence; env provides defaults).
package config

import (
	"flag"
	"fmt"
	"os"
	"strconv"
	"time"

	"git.mkz.me/mycroft/root-me-api/internal/anubis"
)

// Config holds all daemon settings.
type Config struct {
	HTTPAddr        string
	GRPCAddr        string
	RefreshInterval time.Duration
	Pages           int
	UserAgent       string
	RequestTimeout  time.Duration
	LogLevel        string
}

// Load parses configuration from the given args, falling back to environment
// variables and then built-in defaults.
func Load(args []string) (*Config, error) {
	c := &Config{}
	fs := flag.NewFlagSet("scoreboard-apid", flag.ContinueOnError)

	fs.StringVar(&c.HTTPAddr, "http-addr", env("HTTP_ADDR", ":8080"), "HTTP/JSON listen address")
	fs.StringVar(&c.GRPCAddr, "grpc-addr", env("GRPC_ADDR", ":9090"), "gRPC listen address")
	fs.DurationVar(&c.RefreshInterval, "refresh-interval", envDuration("REFRESH_INTERVAL", 10*time.Minute), "scoreboard refresh interval")
	fs.IntVar(&c.Pages, "pages", envInt("SCOREBOARD_PAGES", 4), "number of scoreboard pages to scrape (50 rows each)")
	fs.StringVar(&c.UserAgent, "user-agent", env("USER_AGENT", anubis.DefaultUserAgent), "User-Agent for root-me requests")
	fs.DurationVar(&c.RequestTimeout, "request-timeout", envDuration("REQUEST_TIMEOUT", 30*time.Second), "per-request HTTP timeout")
	fs.StringVar(&c.LogLevel, "log-level", env("LOG_LEVEL", "info"), "log level: debug, info, warn, error")

	if err := fs.Parse(args); err != nil {
		return nil, err
	}
	if c.Pages <= 0 {
		return nil, fmt.Errorf("pages must be > 0")
	}
	if c.RefreshInterval <= 0 {
		return nil, fmt.Errorf("refresh-interval must be > 0")
	}
	return c, nil
}

func env(key, def string) string {
	if v, ok := os.LookupEnv(key); ok {
		return v
	}
	return def
}

func envInt(key string, def int) int {
	if v, ok := os.LookupEnv(key); ok {
		if n, err := strconv.Atoi(v); err == nil {
			return n
		}
	}
	return def
}

func envDuration(key string, def time.Duration) time.Duration {
	if v, ok := os.LookupEnv(key); ok {
		if d, err := time.ParseDuration(v); err == nil {
			return d
		}
	}
	return def
}