package httpclient

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/url"
	"strings"
	"time"

	fhttp "github.com/bogdanfinn/fhttp"
	tls_client "github.com/bogdanfinn/tls-client"
	"github.com/bogdanfinn/tls-client/profiles"
)

const defaultUserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36"

// Client wraps tls-client with Chrome TLS + HTTP/2 fingerprint and proxy support.
type Client struct {
	tlsClient tls_client.HttpClient
	jar       tls_client.CookieJar
}

// NewClient creates a new Client with Chrome TLS + HTTP/2 fingerprint.
func NewClient(proxyURL string) (*Client, error) {
	jar := tls_client.NewCookieJar()

	options := []tls_client.HttpClientOption{
		tls_client.WithClientProfile(profiles.Chrome_146),
		tls_client.WithCookieJar(jar),
		tls_client.WithTimeoutSeconds(30),
		// Follow redirects by default (needed for OAuth flow)
	}

	if proxyURL != "" {
		options = append(options, tls_client.WithProxyUrl(proxyURL))
	}

	client, err := tls_client.NewHttpClient(nil, options...)
	if err != nil {
		return nil, fmt.Errorf("create tls client: %w", err)
	}

	return &Client{
		tlsClient: client,
		jar:       jar,
	}, nil
}

// GetCookieJar returns a wrapper that implements http.CookieJar.
func (c *Client) GetCookieJar() http.CookieJar {
	return &cookieJarWrapper{jar: c.jar}
}

// ResetCookies creates a fresh cookie jar, clearing all existing cookies.
func (c *Client) ResetCookies() {
	jar := tls_client.NewCookieJar()
	c.jar = jar
	c.tlsClient.SetCookieJar(jar)
}

// Do executes a standard net/http request by converting to fhttp.
func (c *Client) Do(req *http.Request) (*http.Response, error) {
	if req.Header.Get("User-Agent") == "" {
		req.Header.Set("User-Agent", defaultUserAgent)
	}
	fReq, err := convertRequest(req)
	if err != nil {
		return nil, err
	}
	fResp, err := c.tlsClient.Do(fReq)
	if err != nil {
		return nil, err
	}
	return convertResponse(fResp), nil
}

// Get performs a GET request with optional headers.
func (c *Client) Get(rawURL string, headers map[string]string) (*http.Response, error) {
	req, err := http.NewRequest(http.MethodGet, rawURL, nil)
	if err != nil {
		return nil, err
	}
	for k, v := range headers {
		req.Header.Set(k, v)
	}
	return c.Do(req)
}

// PostJSON performs a POST request with a JSON body and optional headers.
func (c *Client) PostJSON(rawURL string, body interface{}, headers map[string]string) (*http.Response, error) {
	data, err := json.Marshal(body)
	if err != nil {
		return nil, fmt.Errorf("marshal json body: %w", err)
	}
	req, err := http.NewRequest(http.MethodPost, rawURL, bytes.NewReader(data))
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/json")
	for k, v := range headers {
		req.Header.Set(k, v)
	}
	return c.Do(req)
}

// DoNoRedirect executes an HTTP request without following redirects.
func (c *Client) DoNoRedirect(req *http.Request) (*http.Response, error) {
	if req.Header.Get("User-Agent") == "" {
		req.Header.Set("User-Agent", defaultUserAgent)
	}
	fReq, err := convertRequest(req)
	if err != nil {
		return nil, err
	}
	// Set redirect func to stop following
	c.tlsClient.SetFollowRedirect(false)
	fResp, err := c.tlsClient.Do(fReq)
	c.tlsClient.SetFollowRedirect(true) // restore
	if err != nil {
		return nil, err
	}
	return convertResponse(fResp), nil
}

// PostForm performs a POST request with form-encoded body and optional headers.
func (c *Client) PostForm(rawURL string, values url.Values, headers map[string]string) (*http.Response, error) {
	req, err := http.NewRequest(http.MethodPost, rawURL, strings.NewReader(values.Encode()))
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for k, v := range headers {
		req.Header.Set(k, v)
	}
	return c.Do(req)
}

// DoWithRetry executes a request-building function with retry on 403/network errors.
func (c *Client) DoWithRetry(ctx context.Context, maxRetries int, buildReq func() (*http.Request, error)) (*http.Response, error) {
	var lastErr error
	for attempt := 1; attempt <= maxRetries; attempt++ {
		req, err := buildReq()
		if err != nil {
			return nil, err
		}
		resp, err := c.Do(req)
		if err != nil {
			lastErr = fmt.Errorf("attempt %d: %w", attempt, err)
			log.Printf("[http] attempt %d/%d failed: %v", attempt, maxRetries, err)
		} else if resp.StatusCode == 403 {
			body, _ := ReadBody(resp)
			bodyStr := string(body)

			// Don't retry API-level rejections
			if strings.Contains(bodyStr, "unsupported_country") ||
				strings.Contains(bodyStr, "request_forbidden") {
				return nil, fmt.Errorf("HTTP 403: %s", bodyStr)
			}

			lastErr = fmt.Errorf("attempt %d: HTTP 403 (len=%d)", attempt, len(body))
			log.Printf("[http] attempt %d/%d got 403 from %s: %s", attempt, maxRetries, req.URL.Host, bodyStr)
		} else {
			return resp, nil
		}

		if attempt < maxRetries {
			wait := time.Duration(3*attempt) * time.Second
			log.Printf("[http] waiting %v before retry...", wait)
			select {
			case <-ctx.Done():
				return nil, ctx.Err()
			case <-time.After(wait):
			}
		}
	}
	return nil, fmt.Errorf("failed after %d attempts: %w", maxRetries, lastErr)
}

// ReadBody reads and closes the response body fully.
func ReadBody(resp *http.Response) ([]byte, error) {
	defer resp.Body.Close()
	return io.ReadAll(resp.Body)
}

// ─── Type conversion helpers (net/http <-> fhttp) ───

// convertRequest converts a standard *http.Request to *fhttp.Request.
func convertRequest(req *http.Request) (*fhttp.Request, error) {
	// Read the body fully so fhttp gets a fresh bytes.Reader with known length.
	// This avoids ContentLength mismatches when the original body is an
	// io.NopCloser(*strings.Reader) that fhttp cannot introspect.
	var body io.Reader
	if req.Body != nil {
		bodyBytes, err := io.ReadAll(req.Body)
		if err != nil {
			return nil, fmt.Errorf("read request body for conversion: %w", err)
		}
		body = bytes.NewReader(bodyBytes)
	}

	fReq, err := fhttp.NewRequest(req.Method, req.URL.String(), body)
	if err != nil {
		return nil, err
	}
	// Copy headers
	for k, vs := range req.Header {
		for _, v := range vs {
			fReq.Header.Add(k, v)
		}
	}
	return fReq, nil
}

// convertResponse converts an *fhttp.Response to a standard *http.Response.
func convertResponse(fResp *fhttp.Response) *http.Response {
	resp := &http.Response{
		Status:        fResp.Status,
		StatusCode:    fResp.StatusCode,
		Proto:         fResp.Proto,
		ProtoMajor:    fResp.ProtoMajor,
		ProtoMinor:    fResp.ProtoMinor,
		Body:          fResp.Body,
		ContentLength: fResp.ContentLength,
		Header:        http.Header{},
		Request:       &http.Request{URL: fResp.Request.URL},
	}
	for k, vs := range fResp.Header {
		for _, v := range vs {
			resp.Header.Add(k, v)
		}
	}
	return resp
}

// ─── Cookie jar wrapper (tls_client.CookieJar -> http.CookieJar) ───

type cookieJarWrapper struct {
	jar tls_client.CookieJar
}

func (w *cookieJarWrapper) SetCookies(u *url.URL, cookies []*http.Cookie) {
	fCookies := make([]*fhttp.Cookie, len(cookies))
	for i, c := range cookies {
		fCookies[i] = &fhttp.Cookie{
			Name:     c.Name,
			Value:    c.Value,
			Path:     c.Path,
			Domain:   c.Domain,
			Expires:  c.Expires,
			MaxAge:   c.MaxAge,
			Secure:   c.Secure,
			HttpOnly: c.HttpOnly,
		}
	}
	w.jar.SetCookies(u, fCookies)
}

func (w *cookieJarWrapper) Cookies(u *url.URL) []*http.Cookie {
	fCookies := w.jar.Cookies(u)
	cookies := make([]*http.Cookie, len(fCookies))
	for i, c := range fCookies {
		cookies[i] = &http.Cookie{
			Name:     c.Name,
			Value:    c.Value,
			Path:     c.Path,
			Domain:   c.Domain,
			Expires:  c.Expires,
			MaxAge:   c.MaxAge,
			Secure:   c.Secure,
			HttpOnly: c.HttpOnly,
		}
	}
	return cookies
}