package starnet

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"net/http"
	"net/http/httptrace"
	"net/url"
	"strings"
)

func setReplayableRequestBodyBytes(httpReq *http.Request, data []byte) {
	if httpReq == nil {
		return
	}
	httpReq.Body = io.NopCloser(bytes.NewReader(data))
	httpReq.ContentLength = int64(len(data))
	httpReq.GetBody = func() (io.ReadCloser, error) {
		return io.NopCloser(bytes.NewReader(data)), nil
	}
}

func clearSimpleBodyState(body *BodyConfig) {
	if body == nil {
		return
	}
	body.Bytes = nil
	body.Reader = nil
}

func resetFormBodyState(body *BodyConfig) {
	if body == nil {
		return
	}
	body.FormData = make(map[string][]string)
}

func resetMultipartBodyState(body *BodyConfig) {
	if body == nil {
		return
	}
	body.Files = nil
}

func setBytesBodyConfig(body *BodyConfig, data []byte) {
	if body == nil {
		return
	}
	body.Mode = bodyModeBytes
	body.Bytes = cloneBytes(data)
	body.Reader = nil
	resetFormBodyState(body)
	resetMultipartBodyState(body)
}

func setReaderBodyConfig(body *BodyConfig, reader io.Reader) {
	if body == nil {
		return
	}
	body.Mode = bodyModeReader
	body.Reader = reader
	body.Bytes = nil
	resetFormBodyState(body)
	resetMultipartBodyState(body)
}

func setFormBodyConfig(body *BodyConfig, data map[string][]string) {
	if body == nil {
		return
	}
	body.Mode = bodyModeForm
	clearSimpleBodyState(body)
	resetMultipartBodyState(body)
	body.FormData = cloneStringMapSlice(data)
}

func ensureFormMode(body *BodyConfig) {
	if body == nil {
		return
	}
	if body.Mode == bodyModeForm || body.Mode == bodyModeMultipart {
		if body.FormData == nil {
			body.FormData = make(map[string][]string)
		}
		return
	}
	clearSimpleBodyState(body)
	resetMultipartBodyState(body)
	body.FormData = make(map[string][]string)
	body.Mode = bodyModeForm
}

func ensureMultipartMode(body *BodyConfig) {
	if body == nil {
		return
	}
	if body.Mode == bodyModeMultipart {
		if body.FormData == nil {
			body.FormData = make(map[string][]string)
		}
		return
	}
	if body.Mode != bodyModeForm {
		clearSimpleBodyState(body)
		body.FormData = make(map[string][]string)
	}
	body.Mode = bodyModeMultipart
	if body.FormData == nil {
		body.FormData = make(map[string][]string)
	}
}

func snapshotBytesReader(reader *bytes.Reader) ([]byte, error) {
	if reader == nil {
		return nil, nil
	}
	data := make([]byte, reader.Len())
	_, err := reader.ReadAt(data, reader.Size()-int64(reader.Len()))
	if err != nil && err != io.EOF {
		return nil, err
	}
	return data, nil
}

func snapshotStringReader(reader *strings.Reader) ([]byte, error) {
	if reader == nil {
		return nil, nil
	}
	data := make([]byte, reader.Len())
	_, err := reader.ReadAt(data, reader.Size()-int64(reader.Len()))
	if err != nil && err != io.EOF {
		return nil, err
	}
	return data, nil
}

// applyBody 应用请求体
func (r *Request) applyBody(execCtx context.Context) error {
	r.httpReq.Body = nil
	r.httpReq.GetBody = nil
	r.httpReq.ContentLength = 0

	switch r.config.Body.Mode {
	case bodyModeReader:
		if r.config.Body.Reader == nil {
			return nil
		}
		switch reader := r.config.Body.Reader.(type) {
		case *bytes.Buffer:
			setReplayableRequestBodyBytes(r.httpReq, append([]byte(nil), reader.Bytes()...))
		case *bytes.Reader:
			data, err := snapshotBytesReader(reader)
			if err != nil {
				return wrapError(err, "snapshot bytes reader")
			}
			setReplayableRequestBodyBytes(r.httpReq, data)
		case *strings.Reader:
			data, err := snapshotStringReader(reader)
			if err != nil {
				return wrapError(err, "snapshot strings reader")
			}
			setReplayableRequestBodyBytes(r.httpReq, data)
		default:
			r.httpReq.Body = io.NopCloser(r.config.Body.Reader)
		}
		switch reader := r.config.Body.Reader.(type) {
		case *bytes.Buffer:
			r.httpReq.ContentLength = int64(reader.Len())
		case *bytes.Reader:
			r.httpReq.ContentLength = int64(reader.Len())
		case *strings.Reader:
			r.httpReq.ContentLength = int64(reader.Len())
		}
		return nil
	case bodyModeBytes:
		setReplayableRequestBodyBytes(r.httpReq, r.config.Body.Bytes)
		return nil
	case bodyModeMultipart:
		return r.applyMultipartBody(execCtx)
	case bodyModeForm:
		values := url.Values{}
		for key, items := range r.config.Body.FormData {
			for _, value := range items {
				values.Add(key, value)
			}
		}
		encoded := values.Encode()
		setReplayableRequestBodyBytes(r.httpReq, []byte(encoded))
		return nil
	}

	return nil
}

// prepare 准备请求（应用配置）
func (r *Request) prepare() (err error) {
	if r.applied {
		return nil
	}

	if r.httpReq == nil {
		return fmt.Errorf("http request is nil")
	}

	execCtx := r.ctx
	if execCtx == nil {
		execCtx = context.Background()
	}
	defaultTLSServerName := ""
	if r.httpReq.URL != nil && r.httpReq.URL.Scheme == "https" {
		defaultTLSServerName = r.httpReq.URL.Hostname()
	}
	execCtx = injectRequestConfig(execCtx, r.config, defaultTLSServerName)

	var traceState *traceState
	if r.traceHooks != nil {
		traceState = newTraceState(r.traceHooks)
		execCtx = withTraceState(execCtx, traceState)
		if clientTrace := traceState.clientTrace(); clientTrace != nil {
			execCtx = httptrace.WithClientTrace(execCtx, clientTrace)
		}
	}

	var cancel context.CancelFunc
	if r.config.Network.Timeout > 0 {
		execCtx, cancel = context.WithTimeout(execCtx, r.config.Network.Timeout)
	}
	defer func() {
		if err != nil && cancel != nil {
			cancel()
		}
	}()

	if r.httpClient == nil {
		r.httpClient, err = r.buildHTTPClient()
		if err != nil {
			return err
		}
	}

	if !r.doRaw {
		if len(r.config.Queries) > 0 {
			query := r.httpReq.URL.Query()
			for key, values := range r.config.Queries {
				for _, value := range values {
					query.Add(key, value)
				}
			}
			r.httpReq.URL.RawQuery = query.Encode()
		}

		for key, values := range r.config.Headers {
			if isHostHeaderKey(key) {
				continue
			}
			for _, value := range values {
				r.httpReq.Header.Add(key, value)
			}
		}

		for _, cookie := range r.config.Cookies {
			r.httpReq.AddCookie(cookie)
		}

		if r.config.BasicAuth[0] != "" || r.config.BasicAuth[1] != "" {
			r.httpReq.SetBasicAuth(r.config.BasicAuth[0], r.config.BasicAuth[1])
		}

		if err := r.applyBody(execCtx); err != nil {
			return err
		}

		if r.config.ContentLength > 0 {
			r.httpReq.ContentLength = r.config.ContentLength
		} else if r.config.ContentLength < 0 {
			r.httpReq.ContentLength = 0
		}

		if r.config.AutoCalcContentLength && r.httpReq.Body != nil {
			data, err := io.ReadAll(r.httpReq.Body)
			if err != nil {
				return wrapError(err, "read body for content length")
			}
			setReplayableRequestBodyBytes(r.httpReq, data)
		}

		r.syncRequestHost()
	}

	r.execCtx = execCtx
	r.traceState = traceState
	r.cancel = cancel
	r.httpReq = r.httpReq.WithContext(r.execCtx)
	r.applied = true
	return nil
}

// buildHTTPClient 构建 HTTP Client
func (r *Request) buildHTTPClient() (*http.Client, error) {
	if r.client != nil {
		return r.client.HTTPClient(), nil
	}

	if r.config.CustomTransport && r.config.Transport != nil {
		return &http.Client{
			Transport: &Transport{base: r.config.Transport},
			Timeout:   0,
		}, nil
	}

	return DefaultHTTPClient(), nil
}