package store

import (
	"context"
	"database/sql"
	"errors"
	"reflect"

	"g.fc.run/ai/byre/internal/api"
)

const mergeFactsColumns = `unmerged_commits, unmerged_files, unreviewed_changes, review_snapshot, review_count, review_running, review_failed, review_findings,
	(SELECT json_group_array(json_object('login', login, 'display_name', display_name, 'git_name', git_name, 'git_email', git_email))
		FROM (SELECT * FROM task_participants WHERE task_participants.task_id = tasks.id ORDER BY position))`

type GitFacts struct {
	UnmergedCommits   int
	UnmergedFiles     int
	UnreviewedChanges bool
}

func (s *Store) SettleMergeFacts(ctx context.Context, taskID string, g GitFacts) error {
	return s.write(ctx, func(tx *sql.Tx, emit emitFunc) error {
		t, err := scanTask(tx.QueryRowContext(ctx, `SELECT `+taskColumns+` FROM tasks WHERE id = ?`, taskID))
		if errors.Is(err, sql.ErrNoRows) {
			return ErrNotFound
		}
		if err != nil {
			return err
		}
		if t.Status != api.TaskStatusActive {
			return nil
		}

		f := api.MergeFacts{UnmergedCommits: g.UnmergedCommits, UnmergedFiles: g.UnmergedFiles, UnreviewedChanges: g.UnreviewedChanges}
		err = tx.QueryRowContext(ctx, `SELECT coalesce(max(n), 0) FROM snapshots WHERE task_id = ? AND trigger NOT IN `+cutPointTriggers, taskID).Scan(&f.ReviewSnapshot)
		if err != nil {
			return err
		}
		err = tx.QueryRowContext(ctx, `
			SELECT count(*), coalesce(max(state = ?), 0), coalesce(max(state = ?), 0),
				coalesce(sum(CASE WHEN state = ? THEN (
					SELECT count(*) FROM json_each(nullif(reviews.result, ''), '$.findings') f
					WHERE coalesce(json_extract(reviews.finding_states, '$."' || f.key || '"'), '') != ?
				) END), 0)
			FROM reviews WHERE task_id = ? AND snapshot_n = ?
		`, string(api.ReviewStateRunning), string(api.ReviewStateFailed), string(api.ReviewStateDone), string(api.FindingIgnored), taskID, f.ReviewSnapshot).
			Scan(&f.ReviewCount, &f.ReviewRunning, &f.ReviewFailed, &f.ReviewFindings)
		if err != nil {
			return err
		}
		f.Participants, err = participants(ctx, tx, taskID)
		if err != nil {
			return err
		}

		if reflect.DeepEqual(f, t.MergeFacts) {
			return nil
		}
		_, err = tx.ExecContext(ctx, `
			UPDATE tasks SET unmerged_commits = ?, unmerged_files = ?, unreviewed_changes = ?, review_snapshot = ?, review_count = ?, review_running = ?, review_failed = ?, review_findings = ?
			WHERE id = ?
		`, f.UnmergedCommits, f.UnmergedFiles, f.UnreviewedChanges, f.ReviewSnapshot, f.ReviewCount, f.ReviewRunning, f.ReviewFailed, f.ReviewFindings, taskID)
		if err != nil {
			return err
		}
		_, err = tx.ExecContext(ctx, `DELETE FROM task_participants WHERE task_id = ?`, taskID)
		if err != nil {
			return err
		}
		for i, p := range f.Participants {
			_, err = tx.ExecContext(ctx, `INSERT INTO task_participants (task_id, position, login, display_name, git_name, git_email) VALUES (?, ?, ?, ?, ?, ?)`,
				taskID, i, p.Login, p.DisplayName, p.GitName, p.GitEmail)
			if err != nil {
				return err
			}
		}
		return emit(api.Event{Kind: "task.merge_facts", ProjectId: &t.ProjectId, TaskId: &taskID, Actor: "byre", Payload: ToPayload(f)})
	})
}