//go:build linux || freebsd
// +build linux freebsd

package http

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"mime/multipart"
	"net/http"
	"net/textproto"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"time"

	"codeberg.org/petrbalvin/goget/internal/auth"
	format "codeberg.org/petrbalvin/goget/internal/format"
)

// UploadRequest represents an upload request
type UploadRequest struct {
	// URL to upload to
	URL string

	// Method: PUT or POST
	Method string

	// Path to the file for upload
	FilePath string

	// Form data fields (for POST)
	FormData map[string]string

	// Files for upload (for POST multipart)
	Files []UploadFile

	// Custom headers
	Headers map[string]string

	// Timeout
	Timeout time.Duration

	// Callback pro progress
	ProgressCallback func(current, total int64, speed float64)
}

// UploadFile represents a file for multipart upload
type UploadFile struct {
	// Field name in the form data
	FieldName string

	// Path to the file
	FilePath string

	// Custom file name (optional)
	FileName string

	// Content-Type (optional)
	ContentType string
}

// UploadResult is the result of an upload
type UploadResult struct {
	StatusCode    int
	ContentLength int64
	Duration      time.Duration
	BytesUploaded int64
	Speed         float64
	ResponseBody  string
}

// Upload uploads a file using PUT or POST
func (c *Client) Upload(ctx context.Context, req *UploadRequest) (*UploadResult, error) {
	startTime := time.Now()

	if req.Method == "" {
		req.Method = "PUT"
	}

	// Create request body
	var body io.Reader
	var contentType string
	var totalSize int64

	if req.Method == "PUT" {
		// PUT upload - direct file
		if req.FilePath == "" {
			return nil, fmt.Errorf("put upload requires --upload-file")
		}

		fileInfo, err := os.Stat(req.FilePath)
		if err != nil {
			return nil, fmt.Errorf("failed to stat file: %w", err)
		}
		totalSize = fileInfo.Size()

		file, err := os.Open(req.FilePath)
		if err != nil {
			return nil, fmt.Errorf("failed to open file: %w", err)
		}
		defer file.Close()

		body = file
		contentType = "application/octet-stream"

	} else if req.Method == "POST" {
		// POST upload - form data or multipart
		if len(req.Files) > 0 {
			// Multipart form data
			var bodyBuffer bytes.Buffer
			writer := multipart.NewWriter(&bodyBuffer)

			// Add regular form fields
			for key, value := range req.FormData {
				if err := writer.WriteField(key, value); err != nil {
					return nil, fmt.Errorf("failed to write form field: %w", err)
				}
			}

			// Add files
			for _, uf := range req.Files {
				file, err := os.Open(uf.FilePath)
				if err != nil {
					return nil, fmt.Errorf("failed to open file %s: %w", uf.FilePath, err)
				}

				fileName := uf.FileName
				if fileName == "" {
					fileName = filepath.Base(uf.FilePath)
				}

				contentType := uf.ContentType
				if contentType == "" {
					contentType = "application/octet-stream"
				}

				h := make(textproto.MIMEHeader)
				h.Set("Content-Disposition",
					fmt.Sprintf(`form-data; name="%s"; filename="%s"`, uf.FieldName, fileName))
				h.Set("Content-Type", contentType)

				part, err := writer.CreatePart(h)
				if err != nil {
					file.Close()
					return nil, fmt.Errorf("failed to create form part: %w", err)
				}

				fileInfo, _ := os.Stat(uf.FilePath)
				totalSize += fileInfo.Size()

				_, err = io.Copy(part, file)
				file.Close()
				if err != nil {
					return nil, fmt.Errorf("failed to write file to form: %w", err)
				}
			}

			if err := writer.Close(); err != nil {
				return nil, fmt.Errorf("failed to close multipart writer: %w", err)
			}

			body = &bodyBuffer
			contentType = writer.FormDataContentType()

		} else if len(req.FormData) > 0 {
			// URL-encoded form data
			form := url.Values{}
			for key, value := range req.FormData {
				form.Set(key, value)
			}

			body = strings.NewReader(form.Encode())
			contentType = "application/x-www-form-urlencoded"
			totalSize = int64(len(form.Encode()))

		} else if req.FilePath != "" {
			// POST with raw file body
			fileInfo, err := os.Stat(req.FilePath)
			if err != nil {
				return nil, fmt.Errorf("failed to stat file: %w", err)
			}
			totalSize = fileInfo.Size()

			file, err := os.Open(req.FilePath)
			if err != nil {
				return nil, fmt.Errorf("failed to open file: %w", err)
			}
			defer file.Close()

			body = file
			contentType = "application/octet-stream"
		}
	}

	if body == nil {
		return nil, fmt.Errorf("no upload data provided")
	}

	// Create HTTP request
	httpReq, err := http.NewRequestWithContext(ctx, req.Method, req.URL, body)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	// Set headers
	httpReq.Header.Set("Content-Type", contentType)
	httpReq.Header.Set("User-Agent", c.config.UserAgent)

	for key, value := range req.Headers {
		httpReq.Header.Set(key, value)
	}

	// Apply authentication
	if c.config.Auth.Username != "" {
		authType := c.config.Auth.AuthType
		if authType == "" {
			authType = "auto"
		}

		if authType == "auto" || authType == "basic" {
			// Try basic auth first
			applyBasicAuth(httpReq, c.config.Auth.Username, c.config.Auth.Password)
		}
	}

	// Apply OAuth token if configured
	if c.config.Auth.OAuth != nil && c.config.Auth.OAuth.AccessToken != "" {
		oauthClient := auth.NewOAuthClient(c.config.Auth.OAuth)
		if oauthClient.IsTokenValid() {
			oauthClient.ApplyToken(httpReq)
		}
	}

	// Execute request

	if c.config.RateLimiter != nil {
		// Wrap body with rate limiter for upload
		body = c.config.RateLimiter.WrapReader(body)
		httpReq.Body = io.NopCloser(body)
	}

	// Track progress
	if req.ProgressCallback != nil && totalSize > 0 {
		body = &progressReader{
			r:        body,
			callback: req.ProgressCallback,
			total:    totalSize,
			start:    startTime,
			offset:   0,
		}
		httpReq.Body = io.NopCloser(body)
	}

	resp, err := c.httpClient.Do(httpReq)
	if err != nil {
		return nil, fmt.Errorf("upload request failed: %w", err)
	}
	defer resp.Body.Close()

	// Read response body
	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}

	duration := time.Since(startTime)

	return &UploadResult{
		StatusCode:    resp.StatusCode,
		ContentLength: resp.ContentLength,
		Duration:      duration,
		BytesUploaded: totalSize,
		Speed:         float64(totalSize) / duration.Seconds(),
		ResponseBody:  string(respBody),
	}, nil
}

// UploadSimple performs a simple file upload with progress tracking
func (c *Client) UploadSimple(ctx context.Context, method, targetURL, filePath string, verbose bool) (*UploadResult, error) {
	fileInfo, err := os.Stat(filePath)
	if err != nil {
		return nil, fmt.Errorf("failed to stat file: %w", err)
	}

	totalSize := fileInfo.Size()
	_ = totalSize // Used in progress callback

	file, err := os.Open(filePath)
	if err != nil {
		return nil, fmt.Errorf("failed to open file: %w", err)
	}
	defer file.Close()

	var progressCallback func(int64, int64, float64)
	if verbose {
		progressCallback = func(current, total int64, speed float64) {
			percent := float64(current) / float64(total) * 100
			fmt.Fprintf(os.Stderr, "\r[upload] %s/%s (%.1f%%) %s/s",
				format.Bytes(current),
				format.Bytes(total),
				percent,
				format.Speed(speed))
		}
	}

	req := &UploadRequest{
		URL:              targetURL,
		Method:           method,
		FilePath:         filePath,
		Timeout:          c.config.Transport.Timeout,
		ProgressCallback: progressCallback,
		Headers:          make(map[string]string),
	}

	// Copy headers from client config
	for k, v := range c.config.Headers {
		req.Headers[k] = v
	}

	result, err := c.Upload(ctx, req)
	if err != nil {
		return nil, err
	}

	if verbose {
		fmt.Fprintf(os.Stderr, "\n")
	}

	return result, nil
}

// UploadMultipart performs a multipart POST upload with files
func (c *Client) UploadMultipart(ctx context.Context, targetURL string, files []UploadFile, formData map[string]string, verbose bool) (*UploadResult, error) {
	var progressCallback func(int64, int64, float64)
	if verbose {
		progressCallback = func(current, total int64, speed float64) {
			percent := float64(current) / float64(total) * 100
			fmt.Fprintf(os.Stderr, "\r[upload] %s/%s (%.1f%%) %s/s",
				format.Bytes(current),
				format.Bytes(total),
				percent,
				format.Speed(speed))
		}
	}

	req := &UploadRequest{
		URL:              targetURL,
		Method:           "POST",
		Files:            files,
		FormData:         formData,
		Timeout:          c.config.Transport.Timeout,
		ProgressCallback: progressCallback,
		Headers:          make(map[string]string),
	}

	for k, v := range c.config.Headers {
		req.Headers[k] = v
	}

	result, err := c.Upload(ctx, req)
	if err != nil {
		return nil, err
	}

	if verbose {
		fmt.Fprintf(os.Stderr, "\n")
	}

	return result, nil
}

// applyBasicAuth applies HTTP Basic Authentication to request
func applyBasicAuth(req *http.Request, username, password string) {
	req.SetBasicAuth(username, password)
}