package httputil

import (
	"encoding/json"
	"errors"
	"io"
	"net"
	"net/http"
	"net/url"
	"server/internal/config"
	"server/internal/model/common"
	"server/internal/pkg/errs"
	"server/internal/pkg/validator"
	"strconv"
	"strings"

	"github.com/go-chi/chi/v5"
)

// Pagination 分页请求参数
func Pagination(r *http.Request) *common.Pagination {
	q := r.URL.Query()

	// page 默认 1
	page := int32(1)
	if p := q.Get("page"); p != "" {
		if v, err := strconv.Atoi(p); err == nil && v >= 1 {
			page = int32(v)
		}
	}

	// pageSize 默认 10
	pageSize := int32(10)
	if ps := q.Get("page_size"); ps != "" {
		if v, err := strconv.Atoi(ps); err == nil && v >= 1 && v <= 100 {
			pageSize = int32(v)
		}
	}

	return &common.Pagination{
		Page:     page,
		PageSize: pageSize,
	}
}

func URLParamInt32(r *http.Request, key string) (int32, error) {
	v := chi.URLParam(r, key)

	if v == "" {
		return 0, errs.ErrIDRequired
	}

	n, err := strconv.ParseInt(v, 10, 32)
	if err != nil {
		return 0, errs.ErrInvalidID
	}

	return int32(n), nil
}

func BindJson(r *http.Request, dest any) error {
	if err := json.NewDecoder(r.Body).Decode(dest); err != nil {
		if errors.Is(err, io.EOF) {
			return errs.ErrEmptyBody
		}
		return errs.ErrInvalidJSON
	}

	if err := validator.Struct(dest); err != nil {
		return err
	}

	return nil
}

// ClientIP 获取客户端 IP，依次从 X-Forwarded-For、X-Real-IP、RemoteAddr 取值
func ClientIP(r *http.Request) string {
	if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
		parts := strings.Split(xff, ",")
		if len(parts) > 0 {
			return strings.TrimSpace(parts[0])
		}
	}

	if ip := r.Header.Get("X-Real-IP"); ip != "" {
		return ip
	}

	// RemoteAddr: IP:port
	host, _, err := net.SplitHostPort(r.RemoteAddr)
	if err == nil {
		return host
	}

	return r.RemoteAddr
}

func BuildFileUrl(path *string) string {
	if path == nil || *path == "" {
		return ""
	}

	baseURL := config.GetString("file.base_url")
	if baseURL == "" {
		return ""
	}

	result, err := url.JoinPath(baseURL, *path)
	if err != nil {
		return ""
	}

	return result
}