package storage

import (
	"crm-go/models"
	"crypto/rand"
	"database/sql"
	"encoding/hex"
	"fmt"
	"strings"
	"time"
)

type mysqlFollowUpStorage struct {
	db *sql.DB
}

// NewMySQLFollowUpStorage 创建MySQL跟进存储
func NewMySQLFollowUpStorage() FollowUpStorage {
	return &mysqlFollowUpStorage{
		db: GetDB(),
	}
}

func (fs *mysqlFollowUpStorage) GetAllFollowUps() ([]models.FollowUp, error) {
	query := `
		SELECT id, created_at, customer_name, deal_status, customer_level, 
		       industry, follow_up_time, notification_sent
		FROM followups 
		ORDER BY follow_up_time DESC
	`

	rows, err := fs.db.Query(query)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var followUps []models.FollowUp
	for rows.Next() {
		var f models.FollowUp
		var dealStatus, customerLevel, industry sql.NullString
		var notificationSent int

		err := rows.Scan(
			&f.ID, &f.CreatedAt, &f.CustomerName,
			&dealStatus, &customerLevel, &industry,
			&f.FollowUpTime, &notificationSent,
		)
		if err != nil {
			return nil, err
		}

		f.DealStatus = dealStatus.String
		f.CustomerLevel = customerLevel.String
		f.Industry = industry.String
		f.NotificationSent = notificationSent == 1

		followUps = append(followUps, f)
	}

	return followUps, rows.Err()
}

func (fs *mysqlFollowUpStorage) GetFollowUpByID(id string) (*models.FollowUp, error) {
	query := `
		SELECT id, created_at, customer_name, deal_status, customer_level, 
		       industry, follow_up_time, notification_sent
		FROM followups 
		WHERE id = ?
	`

	var f models.FollowUp
	var dealStatus, customerLevel, industry sql.NullString
	var notificationSent int

	err := fs.db.QueryRow(query, id).Scan(
		&f.ID, &f.CreatedAt, &f.CustomerName,
		&dealStatus, &customerLevel, &industry,
		&f.FollowUpTime, &notificationSent,
	)

	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	f.DealStatus = dealStatus.String
	f.CustomerLevel = customerLevel.String
	f.Industry = industry.String
	f.NotificationSent = notificationSent == 1

	return &f, nil
}

func (fs *mysqlFollowUpStorage) CreateFollowUp(followUp models.FollowUp) error {
	if followUp.ID == "" {
		followUp.ID = generateFollowUpMySQLUUID()
	}
	if followUp.CreatedAt.IsZero() {
		followUp.CreatedAt = time.Now()
	}

	query := `
		INSERT INTO followups (id, created_at, customer_name, deal_status, customer_level, 
		                       industry, follow_up_time, notification_sent)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?)
	`

	notificationSent := 0
	if followUp.NotificationSent {
		notificationSent = 1
	}

	_, err := fs.db.Exec(query,
		followUp.ID, followUp.CreatedAt, followUp.CustomerName,
		followUp.DealStatus, followUp.CustomerLevel, followUp.Industry,
		followUp.FollowUpTime, notificationSent,
	)

	return err
}

func (fs *mysqlFollowUpStorage) UpdateFollowUp(id string, updates models.UpdateFollowUpRequest) error {
	// 首先获取现有记录
	existing, err := fs.GetFollowUpByID(id)
	if err != nil || existing == nil {
		return err
	}

	// 应用更新
	if updates.CustomerName != nil {
		existing.CustomerName = *updates.CustomerName
	}
	if updates.DealStatus != nil {
		existing.DealStatus = *updates.DealStatus
	}
	if updates.CustomerLevel != nil {
		existing.CustomerLevel = *updates.CustomerLevel
	}
	if updates.Industry != nil {
		existing.Industry = *updates.Industry
	}
	if updates.FollowUpTime != nil {
		t, err := time.Parse(time.RFC3339, *updates.FollowUpTime)
		if err == nil {
			existing.FollowUpTime = t
		}
	}
	if updates.NotificationSent != nil {
		existing.NotificationSent = *updates.NotificationSent
	}

	query := `
		UPDATE followups 
		SET customer_name = ?, deal_status = ?, customer_level = ?, 
		    industry = ?, follow_up_time = ?, notification_sent = ?
		WHERE id = ?
	`

	notificationSent := 0
	if existing.NotificationSent {
		notificationSent = 1
	}

	_, err = fs.db.Exec(query,
		existing.CustomerName, existing.DealStatus, existing.CustomerLevel,
		existing.Industry, existing.FollowUpTime, notificationSent,
		id,
	)

	return err
}

func (fs *mysqlFollowUpStorage) DeleteFollowUp(id string) error {
	query := `DELETE FROM followups WHERE id = ?`
	_, err := fs.db.Exec(query, id)
	if err != nil {
		if strings.Contains(err.Error(), "command denied") {
			return fmt.Errorf("数据库权限不足：无法执行删除操作，请联系管理员")
		}
		return err
	}
	return nil
}

func (fs *mysqlFollowUpStorage) SaveFollowUps(followUps []models.FollowUp) error {
	// MySQL版本不需要使用此方法，保留接口兼容
	return nil
}

func (fs *mysqlFollowUpStorage) LoadFollowUps() ([]models.FollowUp, error) {
	return fs.GetAllFollowUps()
}

func (fs *mysqlFollowUpStorage) GetPendingNotifications() ([]models.FollowUp, error) {
	query := `
		SELECT id, created_at, customer_name, deal_status, customer_level, 
		       industry, follow_up_time, notification_sent
		FROM followups 
		WHERE notification_sent = 0 AND follow_up_time < NOW()
	`

	rows, err := fs.db.Query(query)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var pending []models.FollowUp
	for rows.Next() {
		var f models.FollowUp
		var dealStatus, customerLevel, industry sql.NullString
		var notificationSent int

		err := rows.Scan(
			&f.ID, &f.CreatedAt, &f.CustomerName,
			&dealStatus, &customerLevel, &industry,
			&f.FollowUpTime, &notificationSent,
		)
		if err != nil {
			return nil, err
		}

		f.DealStatus = dealStatus.String
		f.CustomerLevel = customerLevel.String
		f.Industry = industry.String
		f.NotificationSent = notificationSent == 1

		pending = append(pending, f)
	}

	return pending, rows.Err()
}

func (fs *mysqlFollowUpStorage) MarkNotificationSent(id string) error {
	query := `UPDATE followups SET notification_sent = 1 WHERE id = ?`
	_, err := fs.db.Exec(query, id)
	return err
}

func generateFollowUpMySQLUUID() string {
	bytes := make([]byte, 16)
	rand.Read(bytes)
	bytes[6] = (bytes[6] & 0x0f) | 0x40 // Version 4
	bytes[8] = (bytes[8] & 0x3f) | 0x80 // Variant
	return hex.EncodeToString(bytes)
}