package repository

import (
	"context"
	"database/sql"
	"time"
)

// Deal represents a sales opportunity
type Deal struct {
	ID            string     `json:"id"`
	CustomerID    string     `json:"customer_id"`
	ContactID     *string    `json:"contact_id"`
	Name          string     `json:"name"`
	Description   string     `json:"description"`
	Value         float64    `json:"value"`
	Currency      string     `json:"currency"`
	Status        string     `json:"status"`
	Stage         string     `json:"stage"`
	Probability   int        `json:"probability"`
	ExpectedClose *time.Time `json:"expected_close"`
	ActualClose   *time.Time `json:"actual_close"`
	AssignedTo    *string    `json:"assigned_to"`
	CreatedAt     time.Time  `json:"created_at"`
	UpdatedAt     time.Time  `json:"updated_at"`
}

// Product represents a sellable product/service
type Product struct {
	ID            string  `json:"id"`
	Name          string  `json:"name"`
	Description   string  `json:"description"`
	SKU           string  `json:"sku"`
	Price         float64 `json:"price"`
	Currency      string  `json:"currency"`
	Unit          string  `json:"unit"`
	IsRecurring   bool    `json:"is_recurring"`
	BillingPeriod string  `json:"billing_period"`
	Status        string  `json:"status"`
}

// SalesRepository handles all sales-related database operations
type SalesRepository struct {
	db *sql.DB
}

func NewSalesRepository(db *sql.DB) *SalesRepository {
	return &SalesRepository{db: db}
}

// ListDeals returns all deals filtered by status
func (r *SalesRepository) ListDeals(ctx context.Context, status string) ([]Deal, error) {
	if status == "" {
		status = "active"
	}

	rows, err := r.db.QueryContext(ctx, `
		SELECT id, customer_id, contact_id, name, description, value, currency, status, stage, probability, expected_close, actual_close, assigned_to, created_at, updated_at
		FROM boc_deals
		WHERE status = $1
		ORDER BY created_at DESC
		LIMIT 100
	`, status)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var deals []Deal
	for rows.Next() {
		var d Deal
		if err := rows.Scan(&d.ID, &d.CustomerID, &d.ContactID, &d.Name, &d.Description, &d.Value,
			&d.Currency, &d.Status, &d.Stage, &d.Probability, &d.ExpectedClose, &d.ActualClose,
			&d.AssignedTo, &d.CreatedAt, &d.UpdatedAt); err != nil {
			continue
		}
		deals = append(deals, d)
	}
	return deals, rows.Err()
}

// GetDeal returns a single deal by ID
func (r *SalesRepository) GetDeal(ctx context.Context, id string) (*Deal, error) {
	var d Deal
	err := r.db.QueryRowContext(ctx, `
		SELECT id, customer_id, contact_id, name, description, value, currency, status, stage, probability, expected_close, actual_close, assigned_to, created_at, updated_at
		FROM boc_deals
		WHERE id = $1
	`, id).Scan(&d.ID, &d.CustomerID, &d.ContactID, &d.Name, &d.Description, &d.Value,
		&d.Currency, &d.Status, &d.Stage, &d.Probability, &d.ExpectedClose, &d.ActualClose,
		&d.AssignedTo, &d.CreatedAt, &d.UpdatedAt)
	if err != nil {
		return nil, err
	}
	return &d, nil
}

// CreateDeal creates a new deal
func (r *SalesRepository) CreateDeal(ctx context.Context, d *Deal) error {
	return r.db.QueryRowContext(ctx, `
		INSERT INTO boc_deals (customer_id, contact_id, name, description, value, currency, status, stage, probability, expected_close, assigned_to)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)
		RETURNING id, created_at, updated_at
	`, d.CustomerID, d.ContactID, d.Name, d.Description, d.Value, d.Currency, d.Status, d.Stage, d.Probability, d.ExpectedClose, d.AssignedTo).Scan(&d.ID, &d.CreatedAt, &d.UpdatedAt)
}

// UpdateDeal updates an existing deal
func (r *SalesRepository) UpdateDeal(ctx context.Context, id string, d *Deal) error {
	_, err := r.db.ExecContext(ctx, `
		UPDATE boc_deals
		SET customer_id = $1, contact_id = $2, name = $3, description = $4, value = $5, currency = $6, status = $7, stage = $8, probability = $9, expected_close = $10, assigned_to = $11, updated_at = NOW()
		WHERE id = $12
	`, d.CustomerID, d.ContactID, d.Name, d.Description, d.Value, d.Currency, d.Status, d.Stage, d.Probability, d.ExpectedClose, d.AssignedTo, id)
	return err
}

// ListProducts returns all active products
func (r *SalesRepository) ListProducts(ctx context.Context) ([]Product, error) {
	rows, err := r.db.QueryContext(ctx, `
		SELECT id, name, description, sku, price, currency, unit, is_recurring, billing_period, status
		FROM boc_products
		WHERE status = 'active'
		ORDER BY name
	`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var products []Product
	for rows.Next() {
		var p Product
		if err := rows.Scan(&p.ID, &p.Name, &p.Description, &p.SKU, &p.Price, &p.Currency, &p.Unit, &p.IsRecurring, &p.BillingPeriod, &p.Status); err != nil {
			continue
		}
		products = append(products, p)
	}
	return products, rows.Err()
}

// GetMRR calculates monthly recurring revenue
func (r *SalesRepository) GetMRR(ctx context.Context) (float64, error) {
	var mrr float64
	err := r.db.QueryRowContext(ctx, `
		SELECT COALESCE(SUM(value * probability / 100.0), 0)
		FROM boc_deals
		WHERE status = 'open' AND stage IN ('negotiation', 'proposal')
	`).Scan(&mrr)
	return mrr, err
}

// GetARR calculates annual recurring revenue
func (r *SalesRepository) GetARR(ctx context.Context) (float64, error) {
	var arr float64
	err := r.db.QueryRowContext(ctx, `
		SELECT COALESCE(SUM(value * probability / 100.0) * 12, 0)
		FROM boc_deals
		WHERE status = 'open' AND stage IN ('negotiation', 'proposal')
	`).Scan(&arr)
	return arr, err
}