package serverevents

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

type Context struct {
	method      string
	eventName   string
	eventData   any
	meta        map[string]any
	eventBefore *Event
	emitter     *EventEmitter
	w           http.ResponseWriter
	r           *http.Request
}

func NewServerEventContext(w http.ResponseWriter, r *http.Request, eventBefore *Event) *Context {
	context := Context{
		eventBefore: eventBefore,
		meta:        make(map[string]any),
		w:           w,
		r:           r,
		emitter:     GetEventEmitter(),
	}
	context.method = r.Method
	context.eventName = r.PathValue("event")
	return &context
}

func (ctx *Context) Emit(event Event) {
	if ctx.emitter == nil {
		return
	}
	ctx.emitter.Emit(event)
}

func (ctx *Context) GetRequest() *http.Request {
	return ctx.r
}

func (ctx *Context) GetResponseWriter() http.ResponseWriter {
	return ctx.w
}

func (ctx *Context) GetEventName() string {
	return ctx.eventName
}

func (ctx *Context) GetMethod() string {
	return ctx.method
}

func (ctx *Context) GetHeaderValue(key string) string {
	return ctx.r.Header.Get(key)
}

func (ctx *Context) Send(status int, contentType string, data []byte) {
	if len(contentType) > 0 {
		ctx.w.Header().Add("Content-Type", contentType)
	}
	ctx.w.WriteHeader(status)
	ctx.w.Write(data)
}

func GetEventData[T any](ctx *Context) (T, error) {
	var result T
	var ok bool
	if ctx.eventData != nil {
		result, ok = ctx.eventData.(T)
		if ok {
			return result, nil
		}
	}
	stream, readBodyErr := io.ReadAll(ctx.r.Body)
	if readBodyErr != nil {
		return result, readBodyErr
	}
	parseErr := json.Unmarshal(stream, &result)
	if parseErr != nil {
		return result, parseErr
	}
	ctx.eventData = result
	return result, nil
}

func SetContextValue[T any](ctx *Context, key string, value T) {
	ctx.meta[key] = value
}

func GetContextValue[T any](ctx *Context, key string) (T, error) {
	var result T
	var ok bool
	tmp := ctx.meta[key]
	if tmp == nil {
		return result, fmt.Errorf("no value with key %s found", key)
	}
	result, ok = tmp.(T)
	if !ok {
		return result, fmt.Errorf("value has expect to be a other DataType %s", key)
	}
	return result, nil
}