package minio

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"time"

	miniogo "github.com/minio/minio-go/v7"
	"github.com/minio/minio-go/v7/pkg/credentials"

	"code.nochebuena.dev/go/health"
	"code.nochebuena.dev/go/launcher"
	"code.nochebuena.dev/go/logz"
)

// Client is the MinIO operation interface for the most common bucket operations.
// Inject it into repositories; use Native() on Component for SDK operations not covered here.
type Client interface {
	// PutObject uploads an object to the given bucket and key.
	PutObject(ctx context.Context, bucket, key string, reader io.Reader, size int64, opts miniogo.PutObjectOptions) (miniogo.UploadInfo, error)
	// RemoveObject deletes an object from the given bucket and key.
	RemoveObject(ctx context.Context, bucket, key string, opts miniogo.RemoveObjectOptions) error
	// GetObject downloads an object and returns it as a readable stream.
	// The caller must close the returned object after reading.
	GetObject(ctx context.Context, bucket, key string, opts miniogo.GetObjectOptions) (*miniogo.Object, error)
	// PresignedGetObject returns a pre-signed URL for downloading an object.
	PresignedGetObject(ctx context.Context, bucket, key string, expires time.Duration, reqParams url.Values) (*url.URL, error)
	// HandleError maps a minio-go error to a typed xerrors value.
	HandleError(err error) error
}

// Component bundles launcher lifecycle, health check, and MinIO client operations.
type Component interface {
	launcher.Component
	health.Checkable
	Client
	// Native returns the underlying minio-go SDK client for operations not covered by Client.
	Native() *miniogo.Client
}

// Config holds MinIO connection settings. The struct is embeddable in application
// config structs and populated from environment variables.
type Config struct {
	Endpoint  string `env:"MINIO_ENDPOINT,required"`
	AccessKey string `env:"MINIO_ACCESS_KEY,required"`
	SecretKey string `env:"MINIO_SECRET_KEY,required"`
	UseSSL    bool   `env:"MINIO_USE_SSL"    envDefault:"false"`
	Bucket    string `env:"MINIO_BUCKET,required"`
	// Region defaults to "us-east-1" — the region MinIO uses by default on self-hosted
	// deployments. Setting a non-empty region bypasses per-request region detection.
	Region string `env:"MINIO_REGION" envDefault:"us-east-1"`
	// Transport is used for testing only. Nil uses the minio-go default transport.
	Transport http.RoundTripper `env:"-"`
}

var _ Component = (*minioComponent)(nil)

type minioComponent struct {
	cfg    Config
	logger logz.Logger
	mc     *miniogo.Client
}

// New returns a MinIO Component. Call lc.Append(mc) to manage its lifecycle.
func New(logger logz.Logger, cfg Config) Component {
	return &minioComponent{cfg: cfg, logger: logger}
}

func (c *minioComponent) OnInit() error {
	opts := &miniogo.Options{
		Creds:     credentials.NewStaticV4(c.cfg.AccessKey, c.cfg.SecretKey, ""),
		Secure:    c.cfg.UseSSL,
		Region:    c.cfg.Region,
		Transport: c.cfg.Transport,
	}
	mc, err := miniogo.New(c.cfg.Endpoint, opts)
	if err != nil {
		return fmt.Errorf("minio: create client: %w", err)
	}
	c.mc = mc
	return nil
}

func (c *minioComponent) OnStart() error {
	if c.mc == nil {
		return fmt.Errorf("minio: client not initialized")
	}
	exists, err := c.mc.BucketExists(context.Background(), c.cfg.Bucket)
	if err != nil {
		return fmt.Errorf("minio: check bucket %q: %w", c.cfg.Bucket, err)
	}
	if !exists {
		if err := c.mc.MakeBucket(context.Background(), c.cfg.Bucket, miniogo.MakeBucketOptions{}); err != nil {
			return fmt.Errorf("minio: create bucket %q: %w", c.cfg.Bucket, err)
		}
		c.logger.Info("minio: bucket created", "bucket", c.cfg.Bucket)
	}
	c.logger.Info("minio: connected", "bucket", c.cfg.Bucket)
	return nil
}

func (c *minioComponent) OnStop() error {
	c.mc = nil
	return nil
}

// GetObject downloads an object as a readable stream. The caller must close the returned object.
func (c *minioComponent) GetObject(ctx context.Context, bucket, key string, opts miniogo.GetObjectOptions) (*miniogo.Object, error) {
	obj, err := c.mc.GetObject(ctx, bucket, key, opts)
	if err != nil {
		return nil, HandleError(err)
	}
	return obj, nil
}

// PutObject uploads an object and maps any minio-go error to a typed xerrors value.
func (c *minioComponent) PutObject(ctx context.Context, bucket, key string, reader io.Reader, size int64, opts miniogo.PutObjectOptions) (miniogo.UploadInfo, error) {
	info, err := c.mc.PutObject(ctx, bucket, key, reader, size, opts)
	if err != nil {
		return miniogo.UploadInfo{}, HandleError(err)
	}
	return info, nil
}

// RemoveObject deletes an object and maps any minio-go error to a typed xerrors value.
func (c *minioComponent) RemoveObject(ctx context.Context, bucket, key string, opts miniogo.RemoveObjectOptions) error {
	return HandleError(c.mc.RemoveObject(ctx, bucket, key, opts))
}

// PresignedGetObject returns a pre-signed download URL and maps any minio-go error to a typed xerrors value.
func (c *minioComponent) PresignedGetObject(ctx context.Context, bucket, key string, expires time.Duration, reqParams url.Values) (*url.URL, error) {
	u, err := c.mc.PresignedGetObject(ctx, bucket, key, expires, reqParams)
	if err != nil {
		return nil, HandleError(err)
	}
	return u, nil
}

// HandleError maps a minio-go error to a typed xerrors value.
func (c *minioComponent) HandleError(err error) error { return HandleError(err) }

// Native returns the underlying minio-go SDK client for operations not covered by Client.
func (c *minioComponent) Native() *miniogo.Client { return c.mc }

// HealthCheck verifies MinIO is reachable by checking that the configured bucket exists.
func (c *minioComponent) HealthCheck(ctx context.Context) error {
	if c.mc == nil {
		return fmt.Errorf("minio: client not initialized")
	}
	_, err := c.mc.BucketExists(ctx, c.cfg.Bucket)
	if err != nil {
		return fmt.Errorf("minio: health check: %w", err)
	}
	return nil
}

// Name returns the component name used by the health check aggregator.
func (c *minioComponent) Name() string { return "minio" }

// Priority returns LevelCritical — MinIO is the primary store for object data;
// an outage means uploads and retrievals fail completely.
func (c *minioComponent) Priority() health.Level { return health.LevelCritical }