package smtp2shoutrrr

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

	"github.com/pelletier/go-toml/v2"
)

// LoadConfig reads the TOML configuration at path and applies its defaults.
func LoadConfig(path string) (*Config, error) {
	f, err := os.Open(path)
	if err != nil {
		return nil, fmt.Errorf("opening config file %q: %w", path, err)
	}
	defer func() { _ = f.Close() }()

	var config Config
	if err := toml.NewDecoder(f).Decode(&config); err != nil {
		return nil, fmt.Errorf("decoding config file %q: %w", path, err)
	}

	config.SetDefaults()

	return &config, nil
}

type Config struct {
	Port       int
	Username   string
	Password   string
	Recipients []ConfigRecipient
	CatchAll   *ConfigRecipient
}

func (c *Config) SetDefaults() {
	if c.Port == 0 {
		c.Port = 11125
	}

	if c.Username == "" {
		slog.Warn("no username provided, using default: username")
		c.Username = "username"
	}

	if c.Password == "" {
		slog.Warn("no password provided, using default: password")
		c.Password = "password"
	}
}

type ConfigRecipient struct {
	Addresses  []string   // email addresses
	Target     string     // deprecated: use Targets instead
	Targets    []string   // shoutrrr addresses (supports multiple)
	targetURLs []*url.URL // cached parsed URLs
}

func (cr *ConfigRecipient) GetTargetURLs() []*url.URL {
	if cr.targetURLs == nil {
		cr.targetURLs = make([]*url.URL, 0)

		// Collect all targets, merging Target into Targets
		allTargets := make([]string, 0)

		// Handle deprecated Target field
		if cr.Target != "" {
			allTargets = append(allTargets, cr.Target)
			slog.Warn("Target field is deprecated, use Targets instead",
				slog.String("addresses", strings.Join(cr.Addresses, ",")))
		}

		// Add all Targets
		allTargets = append(allTargets, cr.Targets...)

		// Parse and cache all URLs
		for _, target := range allTargets {
			parsedURL, err := url.Parse(target)
			if err != nil {
				slog.Error("failed to parse shoutrrr target URL",
					slog.String("target", target),
					slog.String("err", err.Error()))
				continue // Skip invalid URLs
			}
			cr.targetURLs = append(cr.targetURLs, parsedURL)
		}
	}
	return cr.targetURLs
}