package fetch

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"

	"github.com/dop251/goja"
)

type response struct {
	status     int
	statusText string
	url        string
	body       []byte
}

func (r *response) toObject(runtime *goja.Runtime) *goja.Object {
	obj := runtime.NewObject()

	obj.Set("ok", runtime.ToValue(r.status > 199 && r.status < 300))
	obj.Set("status", runtime.ToValue(r.status))
	obj.Set("statusText", runtime.ToValue(r.statusText))
	obj.Set("url", runtime.ToValue(r.url))
	obj.Set("text", runtime.ToValue(r.getText(runtime)))
	obj.Set("json", runtime.ToValue(r.getJSON(runtime)))

	return obj
}

func (r *response) getText(runtime *goja.Runtime) func(goja.FunctionCall) goja.Value {
	return func(goja.FunctionCall) goja.Value {
		return runtime.ToValue(string(r.body))
	}
}

func (r *response) getJSON(runtime *goja.Runtime) func(goja.FunctionCall) goja.Value {
	return func(goja.FunctionCall) goja.Value {
		data := map[string]any{}

		if err := json.Unmarshal(r.body, &data); err != nil {
			// TODO: throw exception?
			return runtime.NewGoError(err)
		}

		return runtime.ToValue(data)
	}
}

type fetchOptions struct {
	Headers map[string]string
}

func doFetch(runtime *goja.Runtime) func(goja.FunctionCall) goja.Value {
	return func(fc goja.FunctionCall) goja.Value {
		url := fc.Argument(0).String()

		opts := map[string]any{}

		params := fc.Argument(1)
		if !goja.IsUndefined(params) {
			if err := runtime.ExportTo(params, &opts); err != nil {
				return runtime.NewGoError(err)
			}
		}

		headers := map[string][]string{}
		if hdrs, ok := opts["headers"]; ok {
			if h, ok := hdrs.(map[string]any); ok {
				for k, v := range h {
					switch vt := v.(type) {
					case string:
						headers[k] = []string{vt}
					case int:
						headers[k] = []string{fmt.Sprintf("%d", vt)}
					}
				}
			}
		}

		res := &response{}

		req, err := http.NewRequest("GET", url, nil)
		if err != nil {
			return runtime.NewGoError(err)
		}

		req.Header = headers

		client := &http.Client{}
		resp, err := client.Do(req)
		if err != nil {
			return runtime.NewGoError(err)
		}
		defer resp.Body.Close()

		res.status = resp.StatusCode
		res.statusText = strings.TrimPrefix(resp.Status, fmt.Sprintf("%d ", resp.StatusCode))
		res.url = resp.Request.URL.String()

		res.body, _ = io.ReadAll(resp.Body)

		return res.toObject(runtime)
	}
}

func Enable(runtime *goja.Runtime) {
	runtime.Set("fetch", doFetch(runtime))
}