package lifecycle

import (
	"context"
	"encoding/json"
	"errors"

	"git.ilapage.cn/ila/yovision/Bell/server/app/alert/model"
	alertQuery "git.ilapage.cn/ila/yovision/Bell/server/app/alert/query"
	"git.ilapage.cn/ila/yovision/Bell/server/app/audit"
	"git.ilapage.cn/ila/yovision/Bell/server/app/auth"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
)

var ErrAlreadyHandled = errors.New("预警已由其他人员开始处理")
var ErrInvalidTransition = errors.New("当前状态不能执行此操作")
var ErrOutcomeRequired = errors.New("请选择现场处理结果")

type CloseInput struct {
	Outcome string `json:"outcome"`
	Note    string `json:"note"`
}
type Result struct {
	Detail     model.Detail `json:"detail"`
	Idempotent bool         `json:"idempotent"`
}
type Service struct {
	DB    *pgxpool.Pool
	Audit audit.Store
	Query alertQuery.Service
}

func hasRole(user auth.User, role string) bool {
	for _, value := range user.Roles {
		if value == role {
			return true
		}
	}
	return false
}
func validOutcome(value string) bool {
	return value == "danger_confirmed" || value == "false_positive" || value == "site_normal" || value == "unable_to_confirm"
}

func (s Service) Ack(ctx context.Context, alertID string, actor auth.User) (Result, error) {
	tx, err := s.DB.Begin(ctx)
	if err != nil {
		return Result{}, err
	}
	var updated string
	err = tx.QueryRow(ctx, `UPDATE bell_alerts SET status='acknowledged',acknowledged_by=$2,acknowledged_at=now(),updated_at=now() WHERE id=$1 AND status='open' RETURNING id::text`, alertID, actor.ID).Scan(&updated)
	if err == nil {
		if _, err = tx.Exec(ctx, `INSERT INTO bell_alert_lifecycle_facts(alert_id,transition,actor_user_id) VALUES($1,'acknowledged',$2)`, alertID, actor.ID); err == nil {
			_, err = tx.Exec(ctx, `INSERT INTO bell_audit_log(actor_user_id,action,target_type,target_id,outcome,details) VALUES($1,'alert.ack','alert',$2,'success','{}')`, actor.ID, alertID)
		}
		if err == nil {
			err = tx.Commit(ctx)
		}
		if err != nil {
			_ = tx.Rollback(ctx)
			return Result{}, err
		}
		detail, err := s.Query.Get(ctx, alertID)
		return Result{Detail: detail}, err
	}
	_ = tx.Rollback(ctx)
	if !errors.Is(err, pgx.ErrNoRows) {
		return Result{}, err
	}
	detail, getErr := s.Query.Get(ctx, alertID)
	if getErr != nil {
		return Result{}, getErr
	}
	if detail.Alert.AcknowledgedBy != nil && *detail.Alert.AcknowledgedBy == actor.ID {
		_ = s.Audit.Record(ctx, &actor.ID, "alert.ack", "alert", &alertID, "failure", map[string]any{"reason": "duplicate"})
		return Result{Detail: detail, Idempotent: true}, nil
	}
	_ = s.Audit.Record(ctx, &actor.ID, "alert.ack", "alert", &alertID, "failure", map[string]any{"reason": "already_handled"})
	return Result{Detail: detail}, ErrAlreadyHandled
}

func (s Service) Close(ctx context.Context, alertID string, input CloseInput, actor auth.User) (Result, error) {
	if !validOutcome(input.Outcome) {
		_ = s.Audit.Record(ctx, &actor.ID, "alert.close", "alert", &alertID, "failure", map[string]any{"reason": "outcome_required"})
		return Result{}, ErrOutcomeRequired
	}
	current, err := s.Query.Get(ctx, alertID)
	if err != nil {
		return Result{}, err
	}
	if current.Alert.Status == "closed" {
		if current.Alert.ClosedBy != nil && *current.Alert.ClosedBy == actor.ID && current.Alert.CloseOutcome != nil && *current.Alert.CloseOutcome == input.Outcome {
			return Result{Detail: current, Idempotent: true}, nil
		}
		_ = s.Audit.Record(ctx, &actor.ID, "alert.close", "alert", &alertID, "failure", map[string]any{"reason": "already_closed"})
		return Result{Detail: current}, ErrInvalidTransition
	}
	admin := hasRole(actor, "administrator")
	if current.Alert.Status != "acknowledged" || (!admin && (current.Alert.AcknowledgedBy == nil || *current.Alert.AcknowledgedBy != actor.ID)) {
		_ = s.Audit.Record(ctx, &actor.ID, "alert.close", "alert", &alertID, "failure", map[string]any{"reason": "invalid_owner_or_state"})
		return Result{Detail: current}, ErrInvalidTransition
	}
	details, _ := json.Marshal(map[string]any{"outcome": input.Outcome, "note": input.Note})
	tx, err := s.DB.Begin(ctx)
	if err != nil {
		return Result{}, err
	}
	defer func() { _ = tx.Rollback(ctx) }()
	result, err := tx.Exec(ctx, `UPDATE bell_alerts SET status='closed',closed_by=$2,closed_at=now(),close_outcome=$3,close_note=nullif($4,''),updated_at=now() WHERE id=$1 AND status='acknowledged'`, alertID, actor.ID, input.Outcome, input.Note)
	if err != nil {
		return Result{}, err
	}
	if result.RowsAffected() != 1 {
		return Result{}, ErrInvalidTransition
	}
	if _, err = tx.Exec(ctx, `INSERT INTO bell_alert_lifecycle_facts(alert_id,transition,actor_user_id,details) VALUES($1,'closed',$2,$3::jsonb)`, alertID, actor.ID, string(details)); err != nil {
		return Result{}, err
	}
	if _, err = tx.Exec(ctx, `INSERT INTO bell_audit_log(actor_user_id,action,target_type,target_id,outcome,details) VALUES($1,'alert.close','alert',$2,'success',$3::jsonb)`, actor.ID, alertID, string(details)); err != nil {
		return Result{}, err
	}
	if err = tx.Commit(ctx); err != nil {
		return Result{}, err
	}
	detail, err := s.Query.Get(ctx, alertID)
	return Result{Detail: detail}, err
}