package handler

import (
	"fmt"
	"log/slog"
	"net/http"
	"spend-sparrow/internal/handler/middleware"
	"spend-sparrow/internal/service"
	"spend-sparrow/internal/template"
	"spend-sparrow/internal/template/dashboard"
	"spend-sparrow/internal/types"
	"spend-sparrow/internal/utils"
	"time"

	"github.com/a-h/templ"
)

type Index interface {
	Handle(router *http.ServeMux)
}

type IndexImpl struct {
	r *Render
	d *service.Dashboard
	c service.Clock
}

func NewIndex(r *Render, d *service.Dashboard, c service.Clock) Index {
	return IndexImpl{
		r: r,
		d: d,
		c: c,
	}
}

func (handler IndexImpl) Handle(router *http.ServeMux) {
	router.Handle("/", handler.handleRootAnd404())
	router.Handle("/empty", handler.handleEmpty())
}

func (handler IndexImpl) handleRootAnd404() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		updateSpan(r)

		user := middleware.GetUser(r)

		htmx := utils.IsHtmx(r)

		var comp templ.Component

		var status int
		if r.URL.Path != "/" {
			comp = template.NotFound()
			status = http.StatusNotFound
		} else {
			if user != nil {
				var err error
				comp, err = handler.dashboard(user, htmx, r)
				if err != nil {
					slog.ErrorContext(r.Context(), "Failed to get dashboard summary", "err", err)
				}
			} else {
				comp = template.Index()
			}
			status = http.StatusOK
		}

		if htmx {
			handler.r.RenderWithStatus(r, w, comp, status)
		} else {
			handler.r.RenderLayoutWithStatus(r, w, comp, user, status)
		}
	}
}

func (handler IndexImpl) dashboard(user *types.User, htmx bool, r *http.Request) (templ.Component, error) {
	var month time.Time
	var err error
	monthStr := r.URL.Query().Get("month")
	if monthStr != "" {
		month, err = time.Parse("2006-01-02", monthStr)
		if err != nil {
			return nil, fmt.Errorf("could not parse timestamp: %w", service.ErrBadRequest)
		}
	} else {
		month = handler.c.Now()
	}

	summary, err := handler.d.Summary(r.Context(), user, month)
	if err != nil {
		return nil, err
	}

	if htmx {
		return dashboard.DashboardData(summary), nil
	} else {
		return dashboard.Dashboard(summary), nil
	}
}

func (handler IndexImpl) handleEmpty() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		updateSpan(r)

		// Return nothing
	}
}