package handlers

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

	"github.com/go-chi/chi/v5"
	"boc/email"
	"boc/pdf"
)

type QuoteHandler struct {
	DB          *sql.DB
	EmailClient *email.Client
}

func NewQuoteHandler(db *sql.DB) *QuoteHandler {
	return &QuoteHandler{DB: db}
}

func (h *QuoteHandler) SetEmailClient(client *email.Client) {
	h.EmailClient = client
}

type Quote struct {
	ID           string     `json:"id"`
	CustomerID   string     `json:"customer_id"`
	QuoteNumber  string     `json:"quote_number"`
	Title        string     `json:"title"`
	Description  string     `json:"description"`
	Status       string     `json:"status"`
	Amount       float64    `json:"amount"`
	TaxAmount    float64    `json:"tax_amount"`
	Currency     string     `json:"currency"`
	ValidUntil   *time.Time `json:"valid_until"`
	AcceptedAt   *time.Time `json:"accepted_at"`
	Notes        string     `json:"notes"`
	Terms        string     `json:"terms"`
	CreatedAt    time.Time  `json:"created_at"`
}

type QuoteItem struct {
	ID          string  `json:"id"`
	QuoteID     string  `json:"quote_id"`
	ProductID   *string `json:"product_id"`
	Description string  `json:"description"`
	Quantity    float64 `json:"quantity"`
	UnitPrice   float64 `json:"unit_price"`
	TaxRate     float64 `json:"tax_rate"`
	Discount    float64 `json:"discount"`
	Total       float64 `json:"total"`
}

func (h *QuoteHandler) ListQuotes(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_number, title, status, amount, currency, valid_until, created_at FROM boc_quotes ORDER BY created_at DESC LIMIT 100`
	} else {
		query = `SELECT id, customer_id, quote_number, title, status, amount, currency, valid_until, created_at FROM boc_quotes 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()

	quotes := []Quote{}
	for rows.Next() {
		var q Quote
		if err := rows.Scan(&q.ID, &q.CustomerID, &q.QuoteNumber, &q.Title, &q.Status, &q.Amount, &q.Currency, &q.ValidUntil, &q.CreatedAt); err != nil {
			continue
		}
		quotes = append(quotes, q)
	}

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

func (h *QuoteHandler) CreateQuote(w http.ResponseWriter, r *http.Request) {
	var req struct {
		CustomerID  string      `json:"customer_id"`
		Title       string      `json:"title"`
		Description string      `json:"description"`
		ValidUntil  *time.Time  `json:"valid_until"`
		Notes       string      `json:"notes"`
		Terms       string      `json:"terms"`
		Items       []QuoteItem `json:"items"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request")
		return
	}

	// Generate quote number
	quoteNumber := fmt.Sprintf("Q-%d", time.Now().Unix())

	// Calculate totals
	var totalAmount, totalTax float64
	for _, item := range req.Items {
		itemTotal := item.Quantity * item.UnitPrice * (1 - item.Discount/100)
		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_quotes (customer_id, quote_number, title, description, amount, tax_amount, currency, valid_until, notes, terms)
		VALUES ($1, $2, $3, $4, $5, $6, 'USD', $7, $8, $9)
		RETURNING id
	`, req.CustomerID, quoteNumber, req.Title, req.Description, totalAmount, totalTax, req.ValidUntil, req.Notes, req.Terms).Scan(&id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to create quote")
		return
	}

	// Insert items
	for _, item := range req.Items {
		itemTotal := item.Quantity * item.UnitPrice * (1 - item.Discount/100)
		_, err = tx.Exec(`
			INSERT INTO boc_quote_items (quote_id, product_id, description, quantity, unit_price, tax_rate, discount, total)
			VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
		`, id, item.ProductID, item.Description, item.Quantity, item.UnitPrice, item.TaxRate, item.Discount, itemTotal)
		if err != nil {
			writeError(w, http.StatusInternalServerError, "failed to create quote 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":  quoteNumber,
		"message": "Quote created",
	})
}

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

	var q Quote
	err := h.DB.QueryRow(`
		SELECT id, customer_id, quote_number, title, description, status, amount, tax_amount, currency, valid_until, accepted_at, notes, terms, created_at
		FROM boc_quotes WHERE id = $1
	`, id).Scan(&q.ID, &q.CustomerID, &q.QuoteNumber, &q.Title, &q.Description, &q.Status, &q.Amount, &q.TaxAmount, &q.Currency, &q.ValidUntil, &q.AcceptedAt, &q.Notes, &q.Terms, &q.CreatedAt)

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

	// Get items
	rows, err := h.DB.Query(`
		SELECT id, product_id, description, quantity, unit_price, tax_rate, discount, total
		FROM boc_quote_items WHERE quote_id = $1 ORDER BY sort_order
	`, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}
	defer rows.Close()

	items := []QuoteItem{}
	for rows.Next() {
		var i QuoteItem
		if err := rows.Scan(&i.ID, &i.ProductID, &i.Description, &i.Quantity, &i.UnitPrice, &i.TaxRate, &i.Discount, &i.Total); err != nil {
			continue
		}
		items = append(items, i)
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"quote": q,
		"items": items,
	})
}

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

	_, err := h.DB.Exec(`
		UPDATE boc_quotes SET status = 'accepted', accepted_at = NOW() WHERE id = $1
	`, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to accept quote")
		return
	}

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

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

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

	// Get quote details
	var customerID string
	var amount, taxAmount float64
	err = tx.QueryRow(`SELECT customer_id, amount, tax_amount FROM boc_quotes WHERE id = $1`, id).Scan(&customerID, &amount, &taxAmount)
	if err != nil {
		writeError(w, http.StatusNotFound, "quote not found")
		return
	}

	// Create order
	orderNumber := fmt.Sprintf("O-%d", time.Now().Unix())
	var orderID string
	err = tx.QueryRow(`
		INSERT INTO boc_orders (customer_id, quote_id, order_number, title, amount, tax_amount, currency, status)
		SELECT customer_id, id, $2, title, amount, tax_amount, currency, 'confirmed'
		FROM boc_quotes WHERE id = $1
		RETURNING id
	`, id, orderNumber).Scan(&orderID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to create order")
		return
	}

	// Copy quote items to order items
	_, err = tx.Exec(`
		INSERT INTO boc_order_items (order_id, product_id, description, quantity, unit_price, tax_rate, discount, total)
		SELECT $1, product_id, description, quantity, unit_price, tax_rate, discount, total
		FROM boc_quote_items WHERE quote_id = $2
	`, orderID, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to copy items")
		return
	}

	// Update quote
	_, err = tx.Exec(`UPDATE boc_quotes SET status = 'converted', converted_to_order_id = $1 WHERE id = $2`, orderID, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to update quote")
		return
	}

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

	writeJSON(w, http.StatusCreated, map[string]interface{}{
		"order_id": orderID,
		"number":   orderNumber,
		"message":  "Quote converted to order",
	})
}

// GenerateQuotePDF generates a PDF for a quote
func (h *QuoteHandler) GenerateQuotePDF(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	var q Quote
	err := h.DB.QueryRow(`
		SELECT id, customer_id, quote_number, title, description, status, amount, tax_amount, currency, valid_until, accepted_at, notes, terms, created_at
		FROM boc_quotes WHERE id = $1
	`, id).Scan(&q.ID, &q.CustomerID, &q.QuoteNumber, &q.Title, &q.Description, &q.Status, &q.Amount, &q.TaxAmount, &q.Currency, &q.ValidUntil, &q.AcceptedAt, &q.Notes, &q.Terms, &q.CreatedAt)
	if err == sql.ErrNoRows {
		writeError(w, http.StatusNotFound, "quote not found")
		return
	}
	if err != nil {
		writeError(w, http.StatusInternalServerError, "database error")
		return
	}

	var customerName, customerAddress string
	h.DB.QueryRow(`SELECT name, address FROM boc_customers WHERE id = $1`, q.CustomerID).Scan(&customerName, &customerAddress)

	validUntil := time.Now().AddDate(0, 0, 30)
	if q.ValidUntil != nil {
		validUntil = *q.ValidUntil
	}

	items := []pdf.QuoteItem{
		{
			Description: q.Title,
			Quantity:    1,
			Unit:        "st",
			UnitPrice:   q.Amount,
			Total:       q.Amount,
		},
	}

	data := pdf.QuoteData{
		QuoteNumber:     q.QuoteNumber,
		QuoteDate:       q.CreatedAt,
		ValidUntil:      validUntil,
		CustomerName:    customerName,
		CustomerAddress: customerAddress,
		Items:           items,
		Subtotal:        q.Amount,
		VATRate:         0.25,
		VATAmount:       q.TaxAmount,
		Total:           q.Amount + q.TaxAmount,
		Currency:        q.Currency,
		CompanyName:     "Landvex Inc",
		CompanyAddress:  "Houston, TX",
		Notes:           q.Notes,
	}

	pdfBytes, err := pdf.GenerateQuote(data)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "pdf generation failed")
		return
	}

	w.Header().Set("Content-Type", "application/pdf")
	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=\"offert-%s.pdf\"", q.QuoteNumber))
	w.Write(pdfBytes)
}

// SendQuoteEmail sends a quote via email with PDF attachment
func (h *QuoteHandler) SendQuoteEmail(w http.ResponseWriter, r *http.Request) {
	if h.EmailClient == nil {
		writeError(w, http.StatusServiceUnavailable, "email not configured")
		return
	}

	id := chi.URLParam(r, "id")

	var req struct {
		To []string `json:"to"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request")
		return
	}

	var q Quote
	err := h.DB.QueryRow(`
		SELECT id, customer_id, quote_number, title, amount, tax_amount, currency, valid_until, created_at
		FROM boc_quotes WHERE id = $1
	`, id).Scan(&q.ID, &q.CustomerID, &q.QuoteNumber, &q.Title, &q.Amount, &q.TaxAmount, &q.Currency, &q.ValidUntil, &q.CreatedAt)
	if err != nil {
		writeError(w, http.StatusNotFound, "quote not found")
		return
	}

	var customerName, customerAddress string
	h.DB.QueryRow(`SELECT name, address FROM boc_customers WHERE id = $1`, q.CustomerID).Scan(&customerName, &customerAddress)

	validUntil := time.Now().AddDate(0, 0, 30)
	if q.ValidUntil != nil {
		validUntil = *q.ValidUntil
	}

	data := pdf.QuoteData{
		QuoteNumber:     q.QuoteNumber,
		QuoteDate:       q.CreatedAt,
		ValidUntil:      validUntil,
		CustomerName:    customerName,
		CustomerAddress: customerAddress,
		Items: []pdf.QuoteItem{
			{
				Description: q.Title,
				Quantity:    1,
				Unit:        "st",
				UnitPrice:   q.Amount,
				Total:       q.Amount,
			},
		},
		Subtotal:       q.Amount,
		VATRate:        0.25,
		VATAmount:      q.TaxAmount,
		Total:          q.Amount + q.TaxAmount,
		Currency:       q.Currency,
		CompanyName:    "Landvex Inc",
		CompanyAddress: "Houston, TX",
	}

	pdfBytes, err := pdf.GenerateQuote(data)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "pdf generation failed")
		return
	}

	err = h.EmailClient.SendQuote(req.To, q.QuoteNumber, pdfBytes, "")
	if err != nil {
		writeError(w, http.StatusInternalServerError, fmt.Sprintf("email failed: %v", err))
		return
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"message": "Quote sent",
		"to":      req.To,
	})
}