package handlers

import (
	"html/template"
	"mealprep/auth"
	"mealprep/database"
	"net/http"
	"strconv"
	"strings"
	"time"
)

// WeekPlanHandler handles the week plan page
func WeekPlanHandler(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r)

	weekPlan, err := database.GetWeekPlan(userID)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	meals, err := database.GetAllMeals(userID)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Group by date
	planByDate := make(map[string][]interface{})
	for _, entry := range weekPlan {
		dateStr := entry.Date.Format("2006-01-02")
		planByDate[dateStr] = append(planByDate[dateStr], entry)
	}

	// Get next 7 days starting from upcoming Monday (or current Monday if today is Monday)
	today := time.Now()

	// Calculate the upcoming Monday
	// If today is Monday, use today. Otherwise, find next Monday.
	weekday := int(today.Weekday())
	daysUntilMonday := (8 - weekday) % 7
	if weekday == 1 { // Today is Monday
		daysUntilMonday = 0
	}

	startDate := today.AddDate(0, 0, daysUntilMonday)

	var dates []string
	for i := 0; i < 7; i++ {
		date := startDate.AddDate(0, 0, i)
		dates = append(dates, date.Format("2006-01-02"))
	}

	tmpl := `
		<div id="weekplan-content">
			<h2>Week Plan</h2>
			<p class="info">Planning week: {{.WeekStart}} - {{.WeekEnd}}</p>

			<div class="week-container">
				{{range $index, $date := .Dates}}
				<div class="day-card">
					<h3>{{formatDate $date}}</h3>

					<!-- Breakfast Section -->
					<div class="meal-type-section">
						<h4 class="meal-type-header">🌅 Breakfast</h4>
						<div class="day-meals" id="day-{{$date}}-breakfast">
							{{$entries := index $.PlanByDate $date}}
							{{range $entries}}
								{{if eq .MealType "breakfast"}}
								<div class="planned-meal" id="plan-{{.ID}}">
									<span>{{.MealName}}</span>
									<button
										hx-delete="/week-plan/{{.ID}}"
										hx-target="#plan-{{.ID}}"
										hx-swap="outerHTML"
										class="delete-btn small">
										×
									</button>
								</div>
								{{end}}
							{{end}}
						</div>
						<form hx-post="/week-plan"
							  hx-target="#day-{{$date}}-breakfast"
							  hx-swap="beforeend"
							  class="add-meal-to-day">
							<input type="hidden" name="date" value="{{$date}}" />
							<input type="hidden" name="meal_type" value="breakfast" />
							<select name="meal_id" required>
								<option value="">Add breakfast...</option>
								{{range $.BreakfastMeals}}
								<option value="{{.ID}}">{{.Name}}</option>
								{{end}}
							</select>
							<button type="submit">+</button>
						</form>
					</div>

					<!-- Lunch Section -->
					<div class="meal-type-section">
						<h4 class="meal-type-header">🍽️ Lunch</h4>
						<div class="day-meals" id="day-{{$date}}-lunch">
							{{$entries := index $.PlanByDate $date}}
							{{range $entries}}
								{{if eq .MealType "lunch"}}
								<div class="planned-meal" id="plan-{{.ID}}">
									<span>{{.MealName}}</span>
									<button
										hx-delete="/week-plan/{{.ID}}"
										hx-target="#plan-{{.ID}}"
										hx-swap="outerHTML"
										class="delete-btn small">
										×
									</button>
								</div>
								{{end}}
							{{end}}
						</div>
						<form hx-post="/week-plan"
							  hx-target="#day-{{$date}}-lunch"
							  hx-swap="beforeend"
							  class="add-meal-to-day">
							<input type="hidden" name="date" value="{{$date}}" />
							<input type="hidden" name="meal_type" value="lunch" />
							<select name="meal_id" required>
								<option value="">Add lunch...</option>
								{{range $.LunchMeals}}
								<option value="{{.ID}}">{{.Name}}</option>
								{{end}}
							</select>
							<button type="submit">+</button>
						</form>
					</div>

					<!-- Snack Section -->
					<div class="meal-type-section">
						<h4 class="meal-type-header">🍪 Snack</h4>
						<div class="day-meals" id="day-{{$date}}-snack">
							{{$entries := index $.PlanByDate $date}}
							{{range $entries}}
								{{if eq .MealType "snack"}}
								<div class="planned-meal" id="plan-{{.ID}}">
									<span>{{.MealName}}</span>
									<button
										hx-delete="/week-plan/{{.ID}}"
										hx-target="#plan-{{.ID}}"
										hx-swap="outerHTML"
										class="delete-btn small">
										×
									</button>
								</div>
								{{end}}
							{{end}}
						</div>
						<form hx-post="/week-plan"
							  hx-target="#day-{{$date}}-snack"
							  hx-swap="beforeend"
							  class="add-meal-to-day">
							<input type="hidden" name="date" value="{{$date}}" />
							<input type="hidden" name="meal_type" value="snack" />
							<select name="meal_id" required>
								<option value="">Add snack...</option>
								{{range $.SnackMeals}}
								<option value="{{.ID}}">{{.Name}}</option>
								{{end}}
							</select>
							<button type="submit">+</button>
						</form>
					</div>
				</div>
				{{end}}
			</div>
		</div>
	`

	funcMap := template.FuncMap{
		"formatDate": func(dateStr string) string {
			date, _ := time.Parse("2006-01-02", dateStr)
			// Show full date with day name
			return date.Format("Monday, Jan 2")
		},
		"index": func(m map[string][]interface{}, key string) []interface{} {
			return m[key]
		},
	}

	// Format week range for display
	weekStart := startDate.Format("Mon, Jan 2")
	weekEnd := startDate.AddDate(0, 0, 6).Format("Mon, Jan 2")

	// Separate meals by type
	var breakfastMeals, lunchMeals, snackMeals []interface{}
	for _, meal := range meals {
		switch meal.MealType {
		case "breakfast":
			breakfastMeals = append(breakfastMeals, meal)
		case "lunch":
			lunchMeals = append(lunchMeals, meal)
		case "snack":
			snackMeals = append(snackMeals, meal)
		}
	}

	data := struct {
		Dates          []string
		PlanByDate     map[string][]interface{}
		BreakfastMeals interface{}
		LunchMeals     interface{}
		SnackMeals     interface{}
		WeekStart      string
		WeekEnd        string
	}{
		Dates:          dates,
		PlanByDate:     planByDate,
		BreakfastMeals: breakfastMeals,
		LunchMeals:     lunchMeals,
		SnackMeals:     snackMeals,
		WeekStart:      weekStart,
		WeekEnd:        weekEnd,
	}

	t := template.Must(template.New("weekplan").Funcs(funcMap).Parse(tmpl))
	t.Execute(w, data)
}

// AddWeekPlanEntryHandler adds a meal to a specific day
func AddWeekPlanEntryHandler(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r)

	if err := r.ParseForm(); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	dateStr := r.FormValue("date")
	mealType := r.FormValue("meal_type")
	mealID, err := strconv.Atoi(r.FormValue("meal_id"))
	if err != nil {
		http.Error(w, "Invalid meal ID", http.StatusBadRequest)
		return
	}

	// Validate meal type
	if mealType != "breakfast" && mealType != "lunch" && mealType != "snack" {
		http.Error(w, "Invalid meal type", http.StatusBadRequest)
		return
	}

	date, err := time.Parse("2006-01-02", dateStr)
	if err != nil {
		http.Error(w, "Invalid date", http.StatusBadRequest)
		return
	}

	if err := database.AddWeekPlanEntry(userID, date, mealID); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Get the meal details
	meal, err := database.GetMealByID(userID, mealID)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Verify meal type matches
	if meal.MealType != mealType {
		http.Error(w, "Meal type does not match", http.StatusBadRequest)
		return
	}

	// Get the ID of the entry we just added
	weekPlan, err := database.GetWeekPlan(userID)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	var entryID int
	for _, entry := range weekPlan {
		if entry.Date.Format("2006-01-02") == dateStr && entry.MealID == mealID {
			entryID = entry.ID
		}
	}

	tmpl := `
		<div class="planned-meal" id="plan-{{.ID}}">
			<span>{{.MealName}}</span>
			<button
				hx-delete="/week-plan/{{.ID}}"
				hx-target="#plan-{{.ID}}"
				hx-swap="outerHTML"
				class="delete-btn small">
				×
			</button>
		</div>
	`

	data := struct {
		ID       int
		MealName string
	}{entryID, meal.Name}

	t := template.Must(template.New("planEntry").Parse(tmpl))
	t.Execute(w, data)
}

// DeleteWeekPlanEntryHandler removes a meal from the week plan
func DeleteWeekPlanEntryHandler(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r)

	idStr := strings.TrimPrefix(r.URL.Path, "/week-plan/")
	id, err := strconv.Atoi(idStr)
	if err != nil {
		http.Error(w, "Invalid ID", http.StatusBadRequest)
		return
	}

	if err := database.DeleteWeekPlanEntry(userID, id); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.WriteHeader(http.StatusOK)
}