package web

import (
	"html/template"
	"net/http"
	"pool-stats/constants"
	"pool-stats/database"
	"pool-stats/models"
	"time"
)

type DailyStatsPageData struct {
	DailyStats []models.DailyStats

	Start string
	End   string

	NextPageAvailable bool
	NextPageStart     string
	NextPageEnd       string

	PrevPageAvailable bool
	PrevPageStart     string
	PrevPageEnd       string
}

func (ws *WebServer) DailyStatsHandler(w http.ResponseWriter, r *http.Request) {
	tmpl, err := template.Must(ws.templates.Clone()).ParseFiles("templates/daily_stats.html")
	if err != nil {
		http.Error(w, "Failed to parse template", http.StatusInternalServerError)
		println("Error parsing template:", err.Error())
		return
	}

	startParam := r.URL.Query().Get("start")
	endParam := r.URL.Query().Get("end")
	var startTime, endTime time.Time

	if startParam == "" || endParam == "" {
		endTime = time.Now().Truncate(24 * time.Hour)
		startTime = endTime.AddDate(0, 0, -constants.DailyStatsPerPage+1)
	} else {
		startTime, err = time.Parse(time.DateOnly, startParam)
		if err != nil {
			http.Error(w, "Invalid start time format", http.StatusBadRequest)
			return
		}

		endTime, err = time.Parse(time.DateOnly, endParam)
		if err != nil {
			http.Error(w, "Invalid end time format", http.StatusBadRequest)
			return
		}
	}

	daysCount := int(endTime.Sub(startTime).Hours() / 24)
	if daysCount < 0 {
		http.Error(w, "End time must be after start time", http.StatusBadRequest)
		return
	}
	if daysCount > constants.DailyStatsPerPage {
		http.Error(w, "Too many days requested", http.StatusBadRequest)
		return
	}

	dailyStats := make([]models.DailyStats, 0)
	for t := endTime; !t.Before(startTime); t = t.AddDate(0, 0, -1) {
		stats, err := database.GetDailyStats(ws.db, t)
		if err != nil {
			http.Error(w, "Failed to fetch daily stats", http.StatusInternalServerError)
			return
		}
		dailyStats = append(dailyStats, *stats)
	}

	nextPageStart := endTime.AddDate(0, 0, 1)
	nextPageEnd := endTime.AddDate(0, 0, constants.DailyStatsPerPage)
	prevPageEnd := startTime.AddDate(0, 0, -1)
	prevPageStart := startTime.AddDate(0, 0, -constants.DailyStatsPerPage)

	data := DailyStatsPageData{
		DailyStats: dailyStats,
		Start:      startTime.Format(time.DateOnly),
		End:        endTime.Format(time.DateOnly),

		NextPageAvailable: nextPageStart.Before(time.Now()),
		NextPageStart:     nextPageStart.Format(time.DateOnly),
		NextPageEnd:       nextPageEnd.Format(time.DateOnly),

		PrevPageAvailable: prevPageStart.After(constants.EpochTime),
		PrevPageStart:     prevPageStart.Format(time.DateOnly),
		PrevPageEnd:       prevPageEnd.Format(time.DateOnly),
	}
	if err := tmpl.ExecuteTemplate(w, "daily_stats.html", data); err != nil {
		http.Error(w, "Failed to render template", http.StatusInternalServerError)
		println("Error rendering template:", err.Error())
		return
	}
}