package store

import (
	"database/sql"
	"errors"
	"fmt"
	"strings"

	"daili/internal/domain"
)

// Customer 客户。
type Customer struct {
	ID         int64
	Tail       string
	Name       string
	GameName   string
	GameServer string
	Contact    string
	Tags       string
	Source     string
	Note       string
	CreatedAt  string
	UpdatedAt  string

	// 列表聚合
	SubCount int
	Summary  string
	Level    string // ok | warn | today | expired | none
}

// TagList 拆分标签。
func (c *Customer) TagList() []string {
	var out []string
	for _, t := range strings.Split(c.Tags, ",") {
		t = strings.TrimSpace(t)
		if t != "" {
			out = append(out, t)
		}
	}
	return out
}

const customerCols = `id,tail,name,game_name,game_server,contact,tags,source,note,created_at,updated_at`

func scanCustomer(row interface{ Scan(dest ...any) error }) (*Customer, error) {
	var c Customer
	err := row.Scan(&c.ID, &c.Tail, &c.Name, &c.GameName, &c.GameServer, &c.Contact,
		&c.Tags, &c.Source, &c.Note, &c.CreatedAt, &c.UpdatedAt)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil, ErrNotFound
		}
		return nil, err
	}
	return &c, nil
}

// CreateCustomer 新建客户（尾号+姓名唯一）。
func (db *DB) CreateCustomer(c *Customer) (int64, error) {
	now := nowStamp()
	res, err := db.sql.Exec(`INSERT INTO customers(tail,name,game_name,game_server,contact,tags,source,note,created_at,updated_at)
		VALUES(?,?,?,?,?,?,?,?,?,?)`,
		strings.TrimSpace(c.Tail), strings.TrimSpace(c.Name), c.GameName, c.GameServer, c.Contact,
		c.Tags, c.Source, c.Note, now, now)
	if err != nil {
		if isUnique(err) {
			return 0, ErrDuplicate
		}
		return 0, err
	}
	return res.LastInsertId()
}

// UpdateCustomer 更新客户。
func (db *DB) UpdateCustomer(c *Customer) error {
	_, err := db.sql.Exec(`UPDATE customers SET tail=?,name=?,game_name=?,game_server=?,contact=?,tags=?,source=?,note=?,updated_at=?
		WHERE id=?`,
		strings.TrimSpace(c.Tail), strings.TrimSpace(c.Name), c.GameName, c.GameServer, c.Contact,
		c.Tags, c.Source, c.Note, nowStamp(), c.ID)
	if err != nil && isUnique(err) {
		return ErrDuplicate
	}
	return err
}

// Customer 取单个客户。
func (db *DB) Customer(id int64) (*Customer, error) {
	return scanCustomer(db.sql.QueryRow(`SELECT `+customerCols+` FROM customers WHERE id=?`, id))
}

// ListCustomers 分页查询客户，并聚合订阅摘要。
func (db *DB) ListCustomers(q string, limit, offset int, today string, warnDays int) ([]Customer, int, error) {
	where := "1=1"
	args := []any{}
	if q = strings.TrimSpace(q); q != "" {
		like := "%" + q + "%"
		where = "(tail LIKE ? OR name LIKE ? OR game_name LIKE ? OR contact LIKE ? OR tags LIKE ?)"
		args = append(args, like, like, like, like, like)
	}
	var total int
	if err := db.sql.QueryRow(`SELECT COUNT(*) FROM customers WHERE `+where, args...).Scan(&total); err != nil {
		return nil, 0, err
	}
	rows, err := db.sql.Query(`SELECT `+customerCols+` FROM customers WHERE `+where+` ORDER BY id DESC LIMIT ? OFFSET ?`,
		append(args, limit, offset)...)
	if err != nil {
		return nil, 0, err
	}
	defer rows.Close()
	out := []Customer{}
	ids := []int64{}
	for rows.Next() {
		c, err := scanCustomer(rows)
		if err != nil {
			return nil, 0, err
		}
		out = append(out, *c)
		ids = append(ids, c.ID)
	}
	if err := rows.Err(); err != nil {
		return nil, 0, err
	}
	if len(ids) > 0 {
		subs, err := db.SubsByCustomers(ids)
		if err != nil {
			return nil, 0, err
		}
		byCustomer := map[int64][]Subscription{}
		for _, s := range subs {
			byCustomer[s.CustomerID] = append(byCustomer[s.CustomerID], s)
		}
		for i := range out {
			list := byCustomer[out[i].ID]
			out[i].SubCount = len(list)
			out[i].Summary, out[i].Level = summarizeSubs(list, today, warnDays)
		}
	}
	return out, total, nil
}

// summarizeSubs 生成“包月日常 剩12天 · 深渊 剩3次”式的摘要与最紧急等级。
func summarizeSubs(subs []Subscription, today string, warnDays int) (string, string) {
	if len(subs) == 0 {
		return "暂无订阅", domain.LevelNone
	}
	t := domain.ParseDateOr(today, domain.Today())
	rank := map[string]int{domain.LevelExpired: 4, domain.LevelToday: 3, domain.LevelWarn: 2, domain.LevelOK: 1, domain.LevelNone: 0}
	worst := domain.LevelNone
	parts := []string{}
	for _, s := range subs {
		e := s.Eval(t, warnDays)
		if e.State == domain.StateClosed {
			continue
		}
		var text string
		if s.Unit == domain.UnitDay {
			switch {
			case e.State == domain.StateExpired:
				text = s.PackageName + " 已过期"
			case e.DaysLeft == 0:
				text = s.PackageName + " 今天到期"
			default:
				text = fmt.Sprintf("%s 剩%d天", s.PackageName, e.RemainingDays)
			}
		} else {
			switch {
			case e.RemainingCount <= 0:
				text = s.PackageName + " 已用尽"
			case e.State == domain.StateExpired:
				text = s.PackageName + " 已过期"
			default:
				text = fmt.Sprintf("%s 剩%d次", s.PackageName, e.RemainingCount)
			}
		}
		parts = append(parts, text)
		if rank[e.Level] > rank[worst] {
			worst = e.Level
		}
	}
	if len(parts) == 0 {
		return "仅历史订阅", domain.LevelNone
	}
	if len(parts) > 2 {
		parts = append(parts[:2], fmt.Sprintf("等%d项", len(parts)))
	}
	return strings.Join(parts, " · "), worst
}

// FindCustomerByTailName 精确查找（用于查重提示）。
func (db *DB) FindCustomerByTailName(tail, name string) (*Customer, error) {
	return scanCustomer(db.sql.QueryRow(`SELECT `+customerCols+` FROM customers WHERE tail=? AND name=?`,
		strings.TrimSpace(tail), strings.TrimSpace(name)))
}

// CustomerCount 客户总数。
func (db *DB) CustomerCount() (int, error) {
	var n int
	err := db.sql.QueryRow(`SELECT COUNT(*) FROM customers`).Scan(&n)
	return n, err
}

// CustomersByTail 按手机尾号精确匹配客户；没有精确命中时退回模糊匹配。
func (db *DB) CustomersByTail(tail string) ([]Customer, error) {
	tail = strings.TrimSpace(tail)
	if tail == "" {
		return nil, nil
	}
	out, err := db.queryCustomers(`SELECT `+customerCols+` FROM customers WHERE tail = ? ORDER BY id`, tail)
	if err != nil {
		return nil, err
	}
	if len(out) > 0 {
		return out, nil
	}
	return db.queryCustomers(`SELECT `+customerCols+` FROM customers WHERE tail LIKE ? ORDER BY id LIMIT 20`, "%"+tail+"%")
}

func (db *DB) queryCustomers(q string, args ...any) ([]Customer, error) {
	rows, err := db.sql.Query(q, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := []Customer{}
	for rows.Next() {
		c, err := scanCustomer(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, *c)
	}
	return out, rows.Err()
}