package config

import (
	"flag"
	"fmt"
	"os"
	"strconv"
	"strings"
)

type Config struct {
	FilePath string
	Host     string
	Port     int
	Debug    bool
	Quiet    bool
	LogReads bool
	LogFile  string
	AuthRole string
}

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

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

func boolEnvOrDefault(key string, fallback bool) bool {
	if v, ok := os.LookupEnv(key); ok {
		switch strings.ToLower(v) {
		case "1", "true", "yes":
			return true
		default:
			return false
		}
	}
	return fallback
}

func Load() (*Config, error) {
	c := &Config{
		FilePath: "data/sample.xlsx",
		Host:     "localhost",
		Port:     3000,
		Debug:    false,
		Quiet:    false,
		LogReads: true,
		AuthRole: "writer",
	}

	flag.StringVar(&c.FilePath, "file", strEnv("RESTXLSX_FILE", c.FilePath), "Path to xlsx/xlsm file")
	flag.StringVar(&c.Host, "host", strEnv("RESTXLSX_HOST", c.Host), "Listen host")
	flag.IntVar(&c.Port, "port", intEnv("RESTXLSX_PORT", c.Port), "HTTP listen port")
	flag.BoolVar(&c.Debug, "debug", boolEnvOrDefault("RESTXLSX_DEBUG", c.Debug), "Enable debug mode (swagger ui, etc.)")
	quietFlag := flag.Bool("quiet", false, "Suppress stdout output")
	flag.BoolVar(&c.LogReads, "log-reads", boolEnvOrDefault("RESTXLSX_LOG_READS", c.LogReads), "Log read operations")
	flag.StringVar(&c.LogFile, "log-file", strEnv("RESTXLSX_LOG_FILE", c.LogFile), "Optional log file path")
	flag.StringVar(&c.AuthRole, "auth", strEnv("RESTXLSX_AUTH", c.AuthRole), "Fallback auth role: admin, writer, reader (used when no OIDC token present)")
	flag.Parse()

	if *quietFlag || strings.EqualFold(os.Getenv("RESTXLSX_CONSOLE"), "quiet") {
		c.Quiet = true
	}

	c.AuthRole = strings.ToLower(c.AuthRole)
	switch c.AuthRole {
	case "admin", "writer", "reader":
	default:
		return nil, fmt.Errorf("invalid auth role %q: must be admin, writer, or reader", c.AuthRole)
	}

	if !strings.HasSuffix(strings.ToLower(c.FilePath), ".xlsx") &&
		!strings.HasSuffix(strings.ToLower(c.FilePath), ".xlsm") {
		return nil, fmt.Errorf("unsupported file format: %s (must be .xlsx or .xlsm)", c.FilePath)
	}

	return c, nil
}