package config

import (
	"fmt"
	"os"

	"gopkg.in/yaml.v3"
)

// APIConfig holds configuration for the HTTP API server.
type APIConfig struct {
	Bind   string `yaml:"bind"`
	Secret string `yaml:"secret"`
}

// Config is the full application configuration loaded from YAML.
type Config struct {
	Server   ServerConfig   `yaml:"server"`
	Storage  StorageConfig  `yaml:"storage"`
	Database DatabaseConfig `yaml:"database"`
	SMTP     SMTPConfig     `yaml:"smtp"`
	API      APIConfig      `yaml:"api"`
	Index    IndexConfig    `yaml:"index"`
	Audit    AuditConfig    `yaml:"audit"`
	Logging  LoggingConfig  `yaml:"logging"`
}

// ServerConfig holds port settings for the main services.
type ServerConfig struct {
	APIPort  int `yaml:"api_port"`
	SMTPPort int `yaml:"smtp_port"`
}

// StorageConfig holds file system paths for email storage.
type StorageConfig struct {
	StorePath  string `yaml:"store_path"`
	AStorePath string `yaml:"astore_path"`
	XapianPath string `yaml:"xapian_path"`
	Keyfile    string `yaml:"keyfile"`
}

// DatabaseConfig holds PostgreSQL connection settings.
type DatabaseConfig struct {
	Host     string `yaml:"host"`
	Port     int    `yaml:"port"`
	Name     string `yaml:"name"`
	User     string `yaml:"user"`
	Password string `yaml:"password"`
	SSLMode  string `yaml:"sslmode"`
}

// DSN builds a PostgreSQL connection string from the config fields.
func (d DatabaseConfig) DSN() string {
	return fmt.Sprintf("postgres://%s:%s@%s:%d/%s?sslmode=%s",
		d.User, d.Password, d.Host, d.Port, d.Name, d.SSLMode)
}

// SMTPConfig holds settings for the embedded SMTP server.
type SMTPConfig struct {
	Enabled    bool     `yaml:"enabled"`
	Bind       string   `yaml:"bind"`
	Domain     string   `yaml:"domain"`
	TLSCert    string   `yaml:"tls_cert"`
	TLSKey     string   `yaml:"tls_key"`
	MaxSizeMB  int      `yaml:"max_size_mb"`
	AllowedIPs []string `yaml:"allowed_ips"`
}

// IndexConfig holds full-text index settings.
type IndexConfig struct {
	Path           string `yaml:"path"`
	Backend        string `yaml:"backend"`
	BatchSize      int    `yaml:"batch_size"`
	AsyncQueueSize int    `yaml:"async_queue_size"`
}

// AuditConfig holds audit log settings.
type AuditConfig struct {
	LogPath       string `yaml:"log_path"`
	RetentionDays int    `yaml:"retention_days"`
}

// LoggingConfig holds application logging settings.
type LoggingConfig struct {
	Path  string `yaml:"path"`
	Level string `yaml:"level"`
}

// Load reads a YAML config file from path and returns a parsed Config.
func Load(path string) (*Config, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}
	var cfg Config
	if err := yaml.Unmarshal(data, &cfg); err != nil {
		return nil, err
	}
	return &cfg, nil
}