package store

import (
	"context"
	"encoding/json"
	"time"

	"github.com/jackc/pgx/v5"
	"github.com/loyaly/behavision-server/internal/api"
)

// RequestCheck queues a check for the shop PC to run on its next sync.
//
// Overwrites any previous request for the same camera rather than queuing a
// second: an operator who presses Check twice wants one answer, now, not two
// answers several minutes apart in an order they cannot predict.
func (s *Store) RequestCheck(ctx context.Context, clientID, id, kind string,
	seconds int) error {

	tag, err := s.pool.Exec(ctx, `
		UPDATE site_cameras
		   SET check_kind = $3, check_seconds = $4, check_requested_at = now(),
		       check_started_at = NULL, check_finished_at = NULL,
		       check_result = NULL, check_image_key = ''
		 WHERE client_id = $1 AND id = $2::uuid AND deleted_at IS NULL`,
		clientID, id, kind, seconds)
	if err != nil {
		return err
	}
	if tag.RowsAffected() == 0 {
		return pgx.ErrNoRows
	}
	return nil
}

// ClaimChecks hands a site its pending checks and marks them started.
//
// One statement, so two syncs racing cannot both claim the same job. A
// placement check asks a human to walk about for 25 seconds; running it twice
// because the agent polled while the first was still going would give the
// operator two contradictory verdicts for one walk.
func (s *Store) ClaimChecks(ctx context.Context, siteID string) ([]api.AgentCheckJob, error) {
	rows, err := s.pool.Query(ctx, `
		UPDATE site_cameras
		   SET check_started_at = now()
		 WHERE site_id = $1::uuid
		   AND check_requested_at IS NOT NULL
		   AND check_finished_at IS NULL
		   AND check_started_at IS NULL
		RETURNING camera_id, check_kind, check_seconds`, siteID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []api.AgentCheckJob
	for rows.Next() {
		var j api.AgentCheckJob
		if err := rows.Scan(&j.CameraID, &j.Kind, &j.Seconds); err != nil {
			return nil, err
		}
		out = append(out, j)
	}
	return out, rows.Err()
}

// RecordCheckResult stores what the shop PC found.
func (s *Store) RecordCheckResult(ctx context.Context, siteID string,
	res api.AgentCheckResult) error {

	detail := res.Detail
	if detail == nil {
		detail = map[string]any{}
	}
	body, err := json.Marshal(map[string]any{
		"ok": res.OK, "verdict": res.Verdict, "headline": res.Headline,
		"advice": res.Advice, "detail": detail,
	})
	if err != nil {
		return err
	}
	_, err = s.pool.Exec(ctx, `
		UPDATE site_cameras
		   SET check_finished_at = now(), check_result = $3::jsonb,
		       check_image_key = CASE WHEN $4 = '' THEN check_image_key ELSE $4 END
		 WHERE site_id = $1::uuid AND camera_id = $2`,
		siteID, res.CameraID, body, res.ImageKey)
	return err
}

// ReleaseStaleChecks un-claims checks a shop PC took and never finished.
//
// Without this a PC that is restarted mid-check leaves the camera showing
// "checking..." for ever, and the operator's only recourse is to guess that
// pressing Check again will help - which it would not, because the request is
// still marked started.
func (s *Store) ReleaseStaleChecks(ctx context.Context, olderThan time.Duration) error {
	_, err := s.pool.Exec(ctx, `
		UPDATE site_cameras
		   SET check_started_at = NULL
		 WHERE check_requested_at IS NOT NULL
		   AND check_finished_at IS NULL
		   AND check_started_at < now() - $1::interval`,
		olderThan.String())
	return err
}

// checkOf reads the stored check for one camera row.
func checkOf(kind string, requested, started, finished *time.Time,
	seconds int, result []byte, imageKey string) api.CameraCheck {

	if requested == nil {
		return api.CameraCheck{}
	}
	c := api.CameraCheck{
		Kind: kind, Seconds: seconds,
		RequestedAt: requested.UTC().Format(time.RFC3339),
		State:       "requested",
	}
	if started != nil {
		c.State = "running"
	}
	if finished != nil {
		c.State = "done"
		c.FinishedAt = finished.UTC().Format(time.RFC3339)
	}
	if len(result) > 0 {
		var body struct {
			OK       bool           `json:"ok"`
			Verdict  string         `json:"verdict"`
			Headline string         `json:"headline"`
			Advice   []string       `json:"advice"`
			Detail   map[string]any `json:"detail"`
		}
		if err := json.Unmarshal(result, &body); err == nil {
			c.OK, c.Verdict, c.Headline = body.OK, body.Verdict, body.Headline
			c.Advice, c.Detail = body.Advice, body.Detail
		}
	}
	c.Image.Key = imageKey
	return c
}