package handlers

import (
	"database/sql"
	"encoding/json"
	"net/http"
	"time"

	"github.com/go-chi/chi/v5"
)

type OrderHandler struct {
	DB *sql.DB
}

func NewOrderHandler(db *sql.DB) *OrderHandler {
	return &OrderHandler{DB: db}
}

type Order struct {
	ID           string     `json:"id"`
	CustomerID   string     `json:"customer_id"`
	QuoteID      *string    `json:"quote_id"`
	OrderNumber  string     `json:"order_number"`
	Title        string     `json:"title"`
	Status       string     `json:"status"`
	Amount       float64    `json:"amount"`
	TaxAmount    float64    `json:"tax_amount"`
	Currency     string     `json:"currency"`
	DeliveryDate *time.Time `json:"delivery_date"`
	ShippedAt    *time.Time `json:"shipped_at"`
	DeliveredAt  *time.Time `json:"delivered_at"`
	TrackingNumber string   `json:"tracking_number"`
	Notes        string     `json:"notes"`
	CreatedAt    time.Time  `json:"created_at"`
}

func (h *OrderHandler) ListOrders(w http.ResponseWriter, r *http.Request) {
	status := r.URL.Query().Get("status")
	if status == "" {
		status = "all"
	}

	var query string
	var args []interface{}
	if status == "all" {
		query = `SELECT id, customer_id, quote_id, order_number, title, status, amount, currency, delivery_date, shipped_at, delivered_at, tracking_number, created_at FROM boc_orders ORDER BY created_at DESC LIMIT 100`
	} else {
		query = `SELECT id, customer_id, quote_id, order_number, title, status, amount, currency, delivery_date, shipped_at, delivered_at, tracking_number, created_at FROM boc_orders WHERE status = $1 ORDER BY created_at DESC LIMIT 100`
		args = append(args, status)
	}

	rows, err := h.DB.Query(query, args...)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer rows.Close()

	orders := []Order{}
	for rows.Next() {
		var o Order
		if err := rows.Scan(&o.ID, &o.CustomerID, &o.QuoteID, &o.OrderNumber, &o.Title, &o.Status, &o.Amount, &o.Currency, &o.DeliveryDate, &o.ShippedAt, &o.DeliveredAt, &o.TrackingNumber, &o.CreatedAt); err != nil {
			continue
		}
		orders = append(orders, o)
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"orders": orders,
		"total":  len(orders),
	})
}

func (h *OrderHandler) CreateOrder(w http.ResponseWriter, r *http.Request) {
	var req struct {
		CustomerID   string     `json:"customer_id"`
		Title        string     `json:"title"`
		DeliveryDate *time.Time `json:"delivery_date"`
		Notes        string     `json:"notes"`
		Items        []struct {
			ProductID   string  `json:"product_id"`
			Description string  `json:"description"`
			Quantity    float64 `json:"quantity"`
			UnitPrice   float64 `json:"unit_price"`
			TaxRate     float64 `json:"tax_rate"`
		} `json:"items"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request")
		return
	}

	orderNumber := "O-" + time.Now().Format("20060102-150405")

	var totalAmount, totalTax float64
	for _, item := range req.Items {
		itemTotal := item.Quantity * item.UnitPrice
		itemTax := itemTotal * (item.TaxRate / 100)
		totalAmount += itemTotal
		totalTax += itemTax
	}

	tx, err := h.DB.Begin()
	if err != nil {
		writeError(w, http.StatusInternalServerError, "transaction error")
		return
	}
	defer tx.Rollback()

	var id string
	err = tx.QueryRow(`
		INSERT INTO boc_orders (customer_id, order_number, title, amount, tax_amount, currency, delivery_date, notes)
		VALUES ($1, $2, $3, $4, $5, 'USD', $6, $7)
		RETURNING id
	`, req.CustomerID, orderNumber, req.Title, totalAmount, totalTax, req.DeliveryDate, req.Notes).Scan(&id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to create order")
		return
	}

	for _, item := range req.Items {
		itemTotal := item.Quantity * item.UnitPrice
		_, err = tx.Exec(`
			INSERT INTO boc_order_items (order_id, product_id, description, quantity, unit_price, tax_rate, total)
			VALUES ($1, $2, $3, $4, $5, $6, $7)
		`, id, item.ProductID, item.Description, item.Quantity, item.UnitPrice, item.TaxRate, itemTotal)
		if err != nil {
			writeError(w, http.StatusInternalServerError, "failed to create order items")
			return
		}
	}

	if err := tx.Commit(); err != nil {
		writeError(w, http.StatusInternalServerError, "commit failed")
		return
	}

	writeJSON(w, http.StatusCreated, map[string]interface{}{
		"id":      id,
		"number":  orderNumber,
		"message": "Order created",
	})
}

func (h *OrderHandler) GetOrder(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	var o Order
	err := h.DB.QueryRow(`
		SELECT id, customer_id, quote_id, order_number, title, status, amount, tax_amount, currency, delivery_date, shipped_at, delivered_at, tracking_number, notes, created_at
		FROM boc_orders WHERE id = $1
	`, id).Scan(&o.ID, &o.CustomerID, &o.QuoteID, &o.OrderNumber, &o.Title, &o.Status, &o.Amount, &o.TaxAmount, &o.Currency, &o.DeliveryDate, &o.ShippedAt, &o.DeliveredAt, &o.TrackingNumber, &o.Notes, &o.CreatedAt)

	if err == sql.ErrNoRows {
		writeError(w, http.StatusNotFound, "order not found")
		return
	}
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}

	writeJSON(w, http.StatusOK, o)
}

func (h *OrderHandler) UpdateOrder(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	var req Order
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request")
		return
	}

	_, err := h.DB.Exec(`
		UPDATE boc_orders
		SET status = $1, delivery_date = $2, tracking_number = $3, notes = $4
		WHERE id = $5
	`, req.Status, req.DeliveryDate, req.TrackingNumber, req.Notes, id)

	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to update order")
		return
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"message": "Order updated",
	})
}

func (h *OrderHandler) ShipOrder(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	var req struct {
		TrackingNumber string `json:"tracking_number"`
	}
	json.NewDecoder(r.Body).Decode(&req)

	_, err := h.DB.Exec(`
		UPDATE boc_orders SET status = 'shipped', shipped_at = NOW(), tracking_number = $1 WHERE id = $2
	`, req.TrackingNumber, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to ship order")
		return
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"message": "Order shipped",
	})
}

func (h *OrderHandler) DeliverOrder(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	_, err := h.DB.Exec(`
		UPDATE boc_orders SET status = 'delivered', delivered_at = NOW() WHERE id = $1
	`, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to deliver order")
		return
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"message": "Order delivered",
	})
}