package archiver

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"io"
	"net/http"
	"path/filepath"
	"time"

	"git.nakama.town/fmartingr/hako/internal/model"
	"git.nakama.town/fmartingr/hako/internal/storage"
)

// DirectDownloadArchiver implements direct HTTP download archival
type DirectDownloadArchiver struct {
	httpClient *http.Client
}

// NewDirectDownloadExtractor creates a new DirectDownloadArchiver
func NewDirectDownloadExtractor() *DirectDownloadArchiver {
	return &DirectDownloadArchiver{
		httpClient: &http.Client{
			Timeout: 5 * time.Minute,
		},
	}
}

// Key returns the unique identifier for this archiver
func (a *DirectDownloadArchiver) Key() string {
	return "direct_download"
}

// Name returns the human-readable name for this archiver
func (a *DirectDownloadArchiver) Name() string {
	return "Direct Download"
}

// IsEnabled checks if this archiver is available
func (a *DirectDownloadArchiver) IsEnabled(ctx context.Context) bool {
	// Direct download is always enabled
	return true
}

// Init initializes the archiver
func (a *DirectDownloadArchiver) Init() error {
	// No initialization needed
	return nil
}

// GetDefaultConfig returns the default configuration
func (a *DirectDownloadArchiver) GetDefaultConfig() any {
	return map[string]any{
		"timeout": "5m",
	}
}

// ApplyConfig applies the provided configuration to the archiver
func (a *DirectDownloadArchiver) ApplyConfig(config map[string]any) error {
	// Parse timeout duration
	if timeoutStr, ok := config["timeout"].(string); ok {
		timeout, err := time.ParseDuration(timeoutStr)
		if err != nil {
			return fmt.Errorf("invalid timeout format: %w", err)
		}
		a.httpClient.Timeout = timeout
	}
	return nil
}

// Archive performs the direct download archival
func (a *DirectDownloadArchiver) Archive(ctx context.Context, link *model.Link, stor storage.Storage) (*ArchiveResult, error) {
	// Create HTTP request
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, link.URL, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	// Set a user agent
	req.Header.Set("User-Agent", "Hako/1.0")

	// Perform the download
	resp, err := a.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to download: %w", err)
	}
	defer func() { _ = resp.Body.Close() }()

	// Check status code
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
	}

	// Detect content type
	contentType := resp.Header.Get("Content-Type")
	if contentType == "" {
		contentType = "application/octet-stream"
	}

	// Generate filename based on URL
	filename := filepath.Base(link.URL)
	if filename == "." || filename == "/" || filename == "" {
		filename = "download"
	}

	// Add extension based on content type if not present
	if filepath.Ext(filename) == "" {
		ext := getExtensionFromContentType(contentType)
		if ext != "" {
			filename += ext
		}
	}

	// Create a pipe to calculate hash while saving
	pipeReader, pipeWriter := io.Pipe()
	hash := sha256.New()
	multiWriter := io.MultiWriter(pipeWriter, hash)

	// Channel for errors from the goroutine
	errChan := make(chan error, 1)
	var path string
	var fileSize int64

	// Copy to storage in goroutine
	go func() {
		defer func() { _ = pipeWriter.Close() }()
		if _, err := io.Copy(multiWriter, resp.Body); err != nil {
			errChan <- fmt.Errorf("failed to copy data: %w", err)
			return
		}
		errChan <- nil
	}()

	// Save to storage
	path, err = stor.Save(ctx, link.ID, filename, pipeReader)
	if err != nil {
		return nil, fmt.Errorf("failed to save file: %w", err)
	}

	// Check for copy errors
	if copyErr := <-errChan; copyErr != nil {
		return nil, copyErr
	}

	// Get file size
	if resp.ContentLength > 0 {
		fileSize = resp.ContentLength
	}

	// Calculate hash
	hashStr := hex.EncodeToString(hash.Sum(nil))

	// Use filename as title (without extension for cleaner display)
	title := filename
	if ext := filepath.Ext(filename); ext != "" {
		title = filename[:len(filename)-len(ext)]
	}
	// Fallback to URL if filename is not meaningful
	if title == "" || title == "." || title == "/" || title == "download" {
		title = link.URL
	}

	result := &ArchiveResult{
		Title: title,
		Files: []FileInfo{
			{
				Filename:   filename,
				MimeType:   contentType,
				FileSize:   fileSize,
				HashSha256: hashStr,
				Path:       path,
			},
		},
	}

	return result, nil
}

// getExtensionFromContentType returns a file extension based on content type
func getExtensionFromContentType(contentType string) string {
	// Simple mapping of common content types to extensions
	types := map[string]string{
		"text/html":                ".html",
		"text/plain":               ".txt",
		"application/pdf":          ".pdf",
		"image/jpeg":               ".jpg",
		"image/png":                ".png",
		"image/gif":                ".gif",
		"image/webp":               ".webp",
		"application/json":         ".json",
		"application/xml":          ".xml",
		"application/zip":          ".zip",
		"application/octet-stream": ".bin",
	}

	if ext, ok := types[contentType]; ok {
		return ext
	}

	return ""
}