package tui

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

func GenerateConfigTOML(cv ConfigValues) (string, error) {
	var sb strings.Builder

	// [server]
	sb.WriteString("# Server Configuration\n")
	sb.WriteString("[server]\n")
	sb.WriteString(fmt.Sprintf("port = %s\n", cv.Server["port"]))
	sb.WriteString(fmt.Sprintf("timeout_seconds = %s\n", cv.Server["timeout"]))
	sb.WriteString(fmt.Sprintf("environment = %q\n", cv.Server["environment"]))
	sb.WriteString("\n")

	// [database]
	sb.WriteString("# Database Configuration\n")
	sb.WriteString("[database]\n")
	sb.WriteString(fmt.Sprintf("type = %q\n", cv.Database["database_type"]))
	sb.WriteString(fmt.Sprintf("url = %q\n", cv.Database["database_url"]))
	sb.WriteString(fmt.Sprintf("max_conns = %s\n", cv.Database["max_conns"]))
	sb.WriteString(fmt.Sprintf("min_conns = %s\n", cv.Database["min_conns"]))
	sb.WriteString("\n")

	// [certificate]
	sb.WriteString("# Certificate Options\n")
	sb.WriteString("[certificate]\n")
	sb.WriteString(fmt.Sprintf("mapped_dir = %q\n", cv.Cert["cert_dir_path"]))
	sb.WriteString(fmt.Sprintf("cert_path = %q\n", "/app/certs/"+cv.Cert["cert_name"]))
	sb.WriteString(fmt.Sprintf("key_path = %q\n", "/app/certs/"+cv.Cert["key_name"]))
	sb.WriteString(fmt.Sprintf("ca_path = %q\n", "/app/certs/"+cv.Cert["ca_name"]))
	sb.WriteString(fmt.Sprintf("server_name = %q\n", cv.Cert["server_name"]))
	sb.WriteString("\n")

	// [application] — hardcoded / pre-defined
	sb.WriteString("# Pre-defined options\n")
	sb.WriteString("[application]\n")
	sb.WriteString("erp = \"TOTVS\"\n")
	sb.WriteString("central_server_url = \"https://warden:8080\"\n")
	sb.WriteString("api_key = \"super secreto\"\n")
	sb.WriteString("\n")

	// [log] — hardcoded defaults
	sb.WriteString("[log]\n")
	sb.WriteString("level = \"debug\"\n")
	sb.WriteString("format = \"text\" # Options: \"json\" or \"text\"\n")

	return sb.String(), nil
}

func GenerateWireguardConfig(cv ConfigValues) (string, error) {
	var sb strings.Builder

	// Primary Wireguard Settings
	sb.WriteString(fmt.Sprintf("PRIVKEY=%s\n", cv.Wireguard["privkey"]))
	sb.WriteString(fmt.Sprintf("VIP=%s\n", cv.Wireguard["vip"]))
	sb.WriteString(fmt.Sprintf("PSK=%s\n", cv.Wireguard["psk"]))
	sb.WriteString(fmt.Sprintf("PROXY_EDPS=%s\n", cv.Wireguard["proxy_edps"]))

	sb.WriteString("\n# MTU Opcional\n")
	if mtu, ok := cv.Wireguard["mtu"]; ok && mtu != "" {
		sb.WriteString(fmt.Sprintf("MTU=%s\n", mtu))
	} else {
		sb.WriteString("# MTU=1380\n")
	}

	sb.WriteString("\n# Especifica o protocolo de transmissao\n")
	sb.WriteString("# Default: UDP -> Manter se possivel, melhor performance e estabilidade.\n")
	sb.WriteString("# Alguns firewalls restritivos podem impedir o trafego UDP.\n")
	sb.WriteString("# Se nao for possivel negociar a abertura com o cliente, tentar usar TCP\n")

	proto := cv.Wireguard["proto"]
	if proto == "" {
		proto = "UDP"
	}
	sb.WriteString(fmt.Sprintf("PROTO=%s\n", proto))

	return sb.String(), nil
}

func WriteConfigFile(cv ConfigValues, path string) error {
	// Validate numeric fields before writing
	numericFields := map[string]string{
		"port":      cv.Server["port"],
		"timeout":   cv.Server["timeout"],
		"max_conns": cv.Database["max_conns"],
		"min_conns": cv.Database["min_conns"],
	}
	for field, val := range numericFields {
		if _, err := strconv.Atoi(val); err != nil {
			return fmt.Errorf("campo %q tem valor inválido: %q", field, val)
		}
	}

	content, err := GenerateConfigTOML(cv)
	if err != nil {
		return err
	}

	return os.WriteFile(path, []byte(content), 0644)
}

func WriteWireguardConfigFile(cv ConfigValues, path string) error {
	// Validate numeric fields before writing
	if mtu, ok := cv.Wireguard["mtu"]; ok && mtu != "" {
		if _, err := strconv.Atoi(mtu); err != nil {
			return fmt.Errorf("o campo MTU deve ser um número, recebido: %q", mtu)
		}
	}

	content, err := GenerateWireguardConfig(cv)
	if err != nil {
		return err
	}

	return os.WriteFile(path, []byte(content), 0644)
}