package handlers

import (
	"database/sql"
	"log"
	"net/http"
	"time"

	"github.com/patel-mann/poll-system/app/internal/models"
	"github.com/patel-mann/poll-system/app/internal/utils"
)

/////////////////////
// Core Validation //
/////////////////////

// ValidateAvailability checks if a user is available at a specific time
func ValidateAvailability(checkDate time.Time, checkTime time.Time, userID int) bool {
	var startTime, endTime time.Time
	day := checkDate.Format("2006-01-02")

	err := models.DB.QueryRow(`
		SELECT start_time, end_time
		FROM availability
		WHERE user_id = $1 AND day_of_week = $2`,
		userID, day).Scan(&startTime, &endTime)

	if err != nil {
		if err != sql.ErrNoRows {
			log.Printf("DB error in ValidateAvailability: %v", err)
		}
		return false
	}

	return checkTime.After(startTime) && checkTime.Before(endTime)
}

////////////////////
// Volunteer CRUD //
////////////////////

// View volunteer availability
func VolunteerGetAvailabilityHandler(w http.ResponseWriter, r *http.Request) {
	userID := models.GetCurrentUserID(w, r)
	username, _ := models.GetCurrentUserName(r)
	role, _ := r.Context().Value("user_role").(int)

	rows, err := models.DB.Query(`
		SELECT availability_id, day_of_week, start_time, end_time, created_at
		FROM availability
		WHERE user_id = $1
		ORDER BY day_of_week DESC`, userID)
	if err != nil {
		log.Println("Error fetching availability:", err)
		http.Error(w, "Database error", http.StatusInternalServerError)
		return
	}
	defer rows.Close()

	var availability []models.Availability
	for rows.Next() {
		var a models.Availability
		if err := rows.Scan(&a.AvailabilityID, &a.DayOfWeek, &a.StartTime, &a.EndTime, &a.CreatedAt); err != nil {
			log.Println("Row scan error:", err)
			continue
		}
		availability = append(availability, a)
	}

	utils.Render(w, "volunteer_schedule.html", map[string]interface{}{
		"Title":            "My Schedule",
		"ShowVolunteerNav": true,
		"IsVolunteer":      true,
		"IsAuthenticated":  true,
		"Availability":     availability,
		"UserName":         username,
		"Role":             role,
		"ActiveSection":    "schedule",
	})
}

// Add or update schedule
func VolunteerPostScheduleHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Redirect(w, r, "/volunteer/schedule", http.StatusSeeOther)
		return
	}

	userID := models.GetCurrentUserID(w, r)
	day := r.FormValue("day")
	start := r.FormValue("start_time")
	end := r.FormValue("end_time")

	if day == "" || start == "" || end == "" {
		http.Error(w, "All fields required", http.StatusBadRequest)
		return
	}

	_, err := models.DB.Exec(`
		INSERT INTO availability (user_id, day_of_week, start_time, end_time, created_at)
		VALUES ($1, $2, $3, $4, NOW())
		ON CONFLICT (user_id, day_of_week)
		DO UPDATE SET start_time = $3, end_time = $4`,
		userID, day, start, end)
	if err != nil {
		log.Println("Insert availability error:", err)
		http.Error(w, "Could not save schedule", http.StatusInternalServerError)
		return
	}

	http.Redirect(w, r, "/volunteer/schedule", http.StatusSeeOther)
}

// Delete schedule
func VolunteerDeleteScheduleHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	userID := models.GetCurrentUserID(w, r)
	idStr := r.FormValue("id")

	_, err := models.DB.Exec(`DELETE FROM availability WHERE availability_id = $1 AND user_id = $2`, idStr, userID)
	if err != nil {
		log.Println("Delete availability error:", err)
		http.Error(w, "Could not delete schedule", http.StatusInternalServerError)
		return
	}

	http.Redirect(w, r, "/volunteer/schedule", http.StatusSeeOther)
}