package starnet

import (
	"context"
	"fmt"
	"net/http"
	"net/url"
	"strings"
)

// Request HTTP 请求
type Request struct {
	ctx     context.Context
	execCtx context.Context // 执行时的 context（注入了配置）
	url     string
	method  string
	err     error // 累积的错误

	config     *RequestConfig
	client     *Client
	httpClient *http.Client
	httpReq    *http.Request

	applied   bool // 是否已应用配置
	doRaw     bool // 是否使用原始请求（不修改）
	autoFetch bool // 是否自动获取响应体
}

// newRequest 创建新请求（内部使用）
func newRequest(ctx context.Context, urlStr string, method string, opts ...RequestOpt) (*Request, error) {
	if method == "" {
		method = http.MethodGet
	}
	method = strings.ToUpper(method)

	// 创建 http.Request
	httpReq, err := http.NewRequestWithContext(ctx, method, urlStr, nil)
	if err != nil {
		return nil, wrapError(err, "create http request")
	}

	// 初始化配置
	config := &RequestConfig{
		Network: NetworkConfig{
			DialTimeout: DefaultDialTimeout,
			Timeout:     DefaultTimeout,
		},
		Headers: make(http.Header),
		Queries: make(map[string][]string),
		Body: BodyConfig{
			FormData: make(map[string][]string),
		},
	}

	// 设置默认 User-Agent
	config.Headers.Set("User-Agent", DefaultUserAgent)

	// POST 请求默认 Content-Type
	if method == http.MethodPost {
		config.Headers.Set("Content-Type", ContentTypeFormURLEncoded)
	}

	req := &Request{
		ctx:       ctx,
		url:       urlStr,
		method:    method,
		config:    config,
		httpReq:   httpReq,
		autoFetch: DefaultFetchRespBody,
	}

	// 应用选项
	for _, opt := range opts {
		if opt != nil {
			if err := opt(req); err != nil {
				req.err = err
				return req, nil // 不返回错误，累积到 req.err
			}
		}
	}

	return req, nil
}

// NewRequest 创建新请求
func NewRequest(url, method string, opts ...RequestOpt) (*Request, error) {
	return newRequest(context.Background(), url, method, opts...)
}

// NewRequestWithContext 创建新请求（带 context）
func NewRequestWithContext(ctx context.Context, url, method string, opts ...RequestOpt) (*Request, error) {
	return newRequest(ctx, url, method, opts...)
}

// NewSimpleRequest 创建新请求（忽略错误，支持链式调用）
func NewSimpleRequest(url, method string, opts ...RequestOpt) *Request {
	req, err := newRequest(context.Background(), url, method, opts...)
	if err != nil {
		// 返回一个带错误的请求
		return &Request{
			ctx:    context.Background(),
			url:    url,
			method: method,
			err:    err,
			config: &RequestConfig{
				Headers: make(http.Header),
				Queries: make(map[string][]string),
				Body: BodyConfig{
					FormData: make(map[string][]string),
				},
			},
		}
	}
	return req
}

// NewSimpleRequestWithContext 创建新请求（带 context，忽略错误）
func NewSimpleRequestWithContext(ctx context.Context, url, method string, opts ...RequestOpt) *Request {
	req, err := newRequest(ctx, url, method, opts...)
	if err != nil {
		return &Request{
			ctx:    ctx,
			url:    url,
			method: method,
			err:    err,
			config: &RequestConfig{
				Headers: make(http.Header),
				Queries: make(map[string][]string),
				Body: BodyConfig{
					FormData: make(map[string][]string),
				},
			},
		}
	}
	return req
}

// Clone 克隆请求
func (r *Request) Clone() *Request {
	cloned := &Request{
		ctx:        r.ctx,
		url:        r.url,
		method:     r.method,
		err:        r.err,
		config:     r.config.Clone(),
		client:     r.client,
		httpClient: r.httpClient,
		applied:    false, // 重置应用状态
		doRaw:      r.doRaw,
		autoFetch:  r.autoFetch,
	}

	// 重新创建 http.Request
	if !r.doRaw {
		cloned.httpReq, _ = http.NewRequestWithContext(cloned.ctx, cloned.method, cloned.url, nil)
	} else {
		cloned.httpReq = r.httpReq
	}

	return cloned
}

// Err 获取累积的错误
func (r *Request) Err() error {
	return r.err
}

// Context 获取 context
func (r *Request) Context() context.Context {
	return r.ctx
}

// SetContext 设置 context
func (r *Request) SetContext(ctx context.Context) *Request {
	if r.err != nil {
		return r
	}
	r.ctx = ctx
	r.httpReq = r.httpReq.WithContext(ctx)
	return r
}

// Method 获取 HTTP 方法
func (r *Request) Method() string {
	return r.method
}

// SetMethod 设置 HTTP 方法
func (r *Request) SetMethod(method string) *Request {
	if r.err != nil {
		return r
	}

	method = strings.ToUpper(method)
	if !validMethod(method) {
		r.err = wrapError(ErrInvalidMethod, "method: %s", method)
		return r
	}

	r.method = method
	r.httpReq.Method = method
	return r
}

// URL 获取 URL
func (r *Request) URL() string {
	return r.url
}

// SetURL 设置 URL
func (r *Request) SetURL(urlStr string) *Request {
	if r.err != nil {
		return r
	}

	if r.doRaw {
		r.err = fmt.Errorf("cannot set URL when using raw request")
		return r
	}

	u, err := url.Parse(urlStr)
	if err != nil {
		r.err = wrapError(ErrInvalidURL, "url: %s", urlStr)
		return r
	}

	r.url = urlStr
	u.Host = removeEmptyPort(u.Host)
	r.httpReq.Host = u.Host
	r.httpReq.URL = u

	// 更新 TLS ServerName
	if r.config.TLS.Config != nil {
		r.config.TLS.Config.ServerName = u.Hostname()
	}

	return r
}

// RawRequest 获取底层 http.Request
func (r *Request) RawRequest() *http.Request {
	return r.httpReq
}

// SetRawRequest 设置底层 http.Request（启用原始模式）
func (r *Request) SetRawRequest(httpReq *http.Request) *Request {
	if r.err != nil {
		return r
	}
	r.httpReq = httpReq
	r.doRaw = true
	return r
}

// EnableRawMode 启用原始模式（不修改请求）
func (r *Request) EnableRawMode() *Request {
	r.doRaw = true
	return r
}

// DisableRawMode 禁用原始模式
func (r *Request) DisableRawMode() *Request {
	r.doRaw = false
	return r
}

// SetAutoFetch 设置是否自动获取响应体
func (r *Request) SetAutoFetch(auto bool) *Request {
	r.autoFetch = auto
	return r
}

// Do 执行请求
func (r *Request) Do() (*Response, error) {
	// 检查累积的错误
	if r.err != nil {
		return nil, r.err
	}

	// 准备请求
	if err := r.prepare(); err != nil {
		return nil, wrapError(err, "prepare request")
	}

	// 执行请求
	httpResp, err := r.httpClient.Do(r.httpReq)
	if err != nil {
		return &Response{
			Response:   &http.Response{},
			request:    r,
			httpClient: r.httpClient,
			body:       &Body{},
		}, wrapError(err, "do request")
	}

	// 创建响应
	resp := &Response{
		Response:   httpResp,
		request:    r,
		httpClient: r.httpClient,
		body: &Body{
			raw: httpResp.Body,
		},
	}

	// 自动获取响应体
	if r.autoFetch {
		resp.body.readAll()
	}

	return resp, nil
}

// Get 发送 GET 请求
func (r *Request) Get() (*Response, error) {
	return r.SetMethod(http.MethodGet).Do()
}

// Post 发送 POST 请求
func (r *Request) Post() (*Response, error) {
	return r.SetMethod(http.MethodPost).Do()
}

// Put 发送 PUT 请求
func (r *Request) Put() (*Response, error) {
	return r.SetMethod(http.MethodPut).Do()
}

// Delete 发送 DELETE 请求
func (r *Request) Delete() (*Response, error) {
	return r.SetMethod(http.MethodDelete).Do()
}