package db

import (
	"context"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"sort"
)

var ErrFindingCaseReviewBusy = errors.New("该任务已有排队或运行中的漏洞整理，请等待完成或停止后重试")

type FindingCaseReviewReservation struct {
	TaskID         int64
	ConversationID int64
	FindingIDs     []int64
}

// Reserve all source tasks atomically, so a concurrent click cannot start a
// second review and a mixed-task request cannot partially enqueue its work.
func (d *DB) CreateFindingCaseReviews(ctx context.Context, batches map[int64][]int64) ([]FindingCaseReviewReservation, error) {
	tasks := make([]int64, 0, len(batches))
	for task := range batches {
		tasks = append(tasks, task)
	}
	sort.Slice(tasks, func(i, j int) bool { return tasks[i] < tasks[j] })
	out := []FindingCaseReviewReservation{}
	err := d.WithEvidenceTx(ctx, func(tx *sql.Tx) error {
		for _, task := range tasks {
			if err := lockCaseTask(tx, task); err != nil {
				return err
			}
			var busy bool
			if err := tx.QueryRow(`SELECT EXISTS(SELECT 1 FROM finding_case_review_runs WHERE task_id=$1 AND state IN ('queued','running'))`, task).Scan(&busy); err != nil {
				return err
			}
			if busy {
				return fmt.Errorf("%w（任务 #%d）", ErrFindingCaseReviewBusy, task)
			}
		}
		for _, task := range tasks {
			ids := []int64{}
			seen := map[int64]bool{}
			for _, id := range batches[task] {
				if seen[id] {
					continue
				}
				seen[id] = true
				var source int64
				if err := tx.QueryRow(`SELECT task_id FROM findings WHERE id=$1`, id).Scan(&source); err != nil {
					return err
				}
				if source != task {
					return errors.New("所选漏洞不属于来源任务")
				}
				ids = append(ids, id)
			}
			if len(ids) == 0 {
				return errors.New("请选择原始上报")
			}
			raw, err := json.Marshal(ids)
			if err != nil {
				return err
			}
			var conv int64
			if err := tx.QueryRow(`INSERT INTO conversations(agent_key,title) VALUES('reporter',$1) RETURNING id`, fmt.Sprintf("漏洞整理 · task#%d", task)).Scan(&conv); err != nil {
				return err
			}
			if _, err := tx.Exec(`INSERT INTO finding_case_review_runs(conversation_id,task_id,finding_ids) VALUES($1,$2,$3)`, conv, task, string(raw)); err != nil {
				return err
			}
			out = append(out, FindingCaseReviewReservation{TaskID: task, ConversationID: conv, FindingIDs: ids})
		}
		return nil
	})
	if err != nil {
		return nil, err
	}
	return out, nil
}