// Package mail_ses - AWS SES email sender.
package mail_ses

import (
	"context"
	"fmt"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/service/sesv2"
	"github.com/aws/aws-sdk-go-v2/service/sesv2/types"
)

type Config struct {
	Region    string // AWS region (e.g., "us-east-1")
	From      string // From address for emails (must be verified in SES)
	AccessKey string // AWS access key ID (optional, uses default credential chain if empty)
	SecretKey string // AWS secret access key (optional, uses default credential chain if empty)
}

type Sender struct {
	client *sesv2.Client
	from   string
}

func NewSender(ctx context.Context, sesConfig Config) (*Sender, error) {
	var cfg aws.Config
	var err error

	// If credentials are provided in config, use them; otherwise use default credential chain
	if sesConfig.AccessKey != "" && sesConfig.SecretKey != "" {
		cfg, err = config.LoadDefaultConfig(ctx,
			config.WithRegion(sesConfig.Region),
			config.WithCredentialsProvider(aws.CredentialsProviderFunc(func(ctx context.Context) (aws.Credentials, error) {
				return aws.Credentials{
					AccessKeyID:     sesConfig.AccessKey,
					SecretAccessKey: sesConfig.SecretKey,
				}, nil
			})),
		)
	} else {
		// Use default credential chain (env vars, ~/.aws/credentials, IAM role, etc.)
		cfg, err = config.LoadDefaultConfig(ctx, config.WithRegion(sesConfig.Region))
	}

	if err != nil {
		return nil, fmt.Errorf("loading AWS config: %w", err)
	}

	client := sesv2.NewFromConfig(cfg)

	return &Sender{
		client: client,
		from:   sesConfig.From,
	}, nil
}

func (s *Sender) Send(ctx context.Context, email, subject, body string) error {
	input := &sesv2.SendEmailInput{
		FromEmailAddress: aws.String(s.from),
		Destination: &types.Destination{
			ToAddresses: []string{email},
		},
		Content: &types.EmailContent{
			Simple: &types.Message{
				Subject: &types.Content{
					Data:    aws.String(subject),
					Charset: aws.String("UTF-8"),
				},
				Body: &types.Body{
					Text: &types.Content{
						Data:    aws.String(body),
						Charset: aws.String("UTF-8"),
					},
				},
			},
		},
	}

	_, err := s.client.SendEmail(ctx, input)
	if err != nil {
		return fmt.Errorf("sending email via SES: %w", err)
	}

	return nil
}