package services

import (
	"context"
	"regexp"
	"slices"
	"strings"

	"code.tczkiot.com/wlw/ai-agent/identity"
	"code.tczkiot.com/wlw/ai-agent/internal/models"
	"code.tczkiot.com/wlw/ai-agent/internal/pkg/enums"
	"code.tczkiot.com/wlw/ai-agent/internal/pkg/utils"
)

var quickActionBusinessIdentifierPattern = regexp.MustCompile(`[A-Za-z0-9][A-Za-z0-9:_-]{5,63}`)

// resolveQuickActionConversation builds the business context used by the H5
// quick-service menu without changing the conversation's owner identity. Web
// visitors must remain guests for authorization, while an already supplied or
// previously recognised card/device number determines which actions are shown.
func resolveQuickActionConversation(ctx context.Context, conversation *models.Conversation) *models.Conversation {
	if conversation == nil || quickActionBoundBusinessType(conversation.CustomerType) {
		return conversation
	}

	hints := quickActionIdentityHints(conversation)
	for _, hint := range hints {
		subject, ok, err := resolveQuickActionBusinessSubject(ctx, hint)
		if err != nil || !ok {
			continue
		}
		resolved := *conversation
		resolved.CustomerType = string(subject.Type)
		resolved.CustomerID = subject.ID
		resolved.CustomerExternalID = strings.TrimSpace(subject.Identifier)
		if subject.Type == identity.SubjectCard && strings.TrimSpace(subject.Username) != "" {
			resolved.CustomerExternalID = strings.TrimSpace(subject.Username)
		}
		resolved.CustomerName = strings.TrimSpace(subject.Name)
		return &resolved
	}
	return conversation
}

type quickActionIdentityHint struct {
	identifier string
	types      []identity.SubjectType
}

func quickActionIdentityHints(conversation *models.Conversation) []quickActionIdentityHint {
	if conversation == nil {
		return nil
	}
	hints := make([]quickActionIdentityHint, 0, 4)
	if value, ok := strings.CutPrefix(strings.TrimSpace(conversation.CustomerExternalID), "card:"); ok && strings.TrimSpace(value) != "" {
		hints = append(hints, quickActionIdentityHint{identifier: strings.TrimSpace(value), types: []identity.SubjectType{identity.SubjectCard}})
	}
	if value, ok := strings.CutPrefix(strings.TrimSpace(conversation.CustomerExternalID), "device:"); ok && strings.TrimSpace(value) != "" {
		hints = append(hints, quickActionIdentityHint{identifier: strings.TrimSpace(value), types: []identity.SubjectType{identity.SubjectDevice}})
	}

	history, _, _ := MessageService.FindByConversationIDCursor(
		conversation.ID, 0, 20, string(enums.IMSenderTypeCustomer), "",
	)
	for index := len(history) - 1; index >= 0; index-- {
		item := history[index]
		if item.MessageType != enums.IMMessageTypeText && item.MessageType != enums.IMMessageTypeHTML {
			continue
		}
		content := strings.TrimSpace(utils.BuildRuntimeMessageText(item.MessageType, item.Content))
		candidates, explicit, types := quickActionBusinessCandidates(content)
		if !explicit {
			continue
		}
		for _, candidate := range candidates {
			hints = append(hints, quickActionIdentityHint{identifier: candidate, types: types})
		}
	}
	return hints
}

func quickActionBusinessCandidates(content string) ([]string, bool, []identity.SubjectType) {
	content = strings.TrimSpace(content)
	if content == "" {
		return nil, false, nil
	}
	candidates := slices.Compact(quickActionBusinessIdentifierPattern.FindAllString(content, -1))
	lower := strings.ToLower(content)
	explicit := strings.Contains(content, "卡号") || strings.Contains(content, "卡板") ||
		strings.Contains(content, "设备号") || strings.Contains(lower, "iccid") || strings.Contains(lower, "imei")
	if len(candidates) == 1 && candidates[0] == content {
		explicit = true
	}
	types := []identity.SubjectType{identity.SubjectCard, identity.SubjectDevice}
	switch {
	case strings.Contains(content, "设备") || strings.Contains(lower, "imei"):
		types = []identity.SubjectType{identity.SubjectDevice}
	case strings.Contains(content, "卡号") || strings.Contains(content, "卡板") || strings.Contains(lower, "iccid"):
		types = []identity.SubjectType{identity.SubjectCard}
	}
	return candidates, explicit, types
}

func resolveQuickActionBusinessSubject(ctx context.Context, hint quickActionIdentityHint) (identity.Subject, bool, error) {
	for _, subjectType := range hint.types {
		subjects, err := SubjectService.Query(ctx, identity.Query{
			Types:       []identity.SubjectType{subjectType},
			Keyword:     hint.identifier,
			EnabledOnly: true,
		})
		if err != nil {
			return identity.Subject{}, false, err
		}
		for _, subject := range subjects {
			if subject.Type != subjectType || !subject.Enabled {
				continue
			}
			if strings.EqualFold(strings.TrimSpace(subject.Identifier), hint.identifier) ||
				strings.EqualFold(strings.TrimSpace(subject.Username), hint.identifier) {
				return subject, true, nil
			}
		}
	}
	return identity.Subject{}, false, nil
}

func quickActionBoundBusinessType(customerType string) bool {
	switch identity.SubjectType(strings.TrimSpace(customerType)) {
	case identity.SubjectCard, identity.SubjectDevice, identity.SubjectMallUser:
		return true
	default:
		return false
	}
}