package api

import (
	"encoding/csv"
	"net/http"
	"strconv"
	"strings"
	"time"
)

// GET /api/logbook/export — exports the caller's in-scope logbook as CSV.
//
// This is the "readable electronic format" disclosure path required by BEK 1649
// § 5: retained 5 years and producible on request from Trafikstyrelsen (and,
// under the 2026 hearing draft, the police). CSV is an open format, so it holds
// regardless of whether the source records came from a manual entry or an
// automatic FDR export.
func (s *Server) handleExportLogbook(w http.ResponseWriter, r *http.Request) {
	who := caller(r)
	drones, err := s.dronesInScope(r.Context(), who)
	if err != nil {
		gatewayError(w, err)
		return
	}
	var list struct {
		Items []flightRecord `json:"items"`
	}
	if _, err := s.listRecords(r.Context(), "flights", flightScopeFilter(who),
		"operation_date,start_time", &list); err != nil {
		gatewayError(w, err)
		return
	}

	filename := "pilotvault-logbook-" + time.Now().Format("2006-01-02") + ".csv"
	w.Header().Set("Content-Type", "text/csv; charset=utf-8")
	w.Header().Set("Content-Disposition", "attachment; filename=\""+filename+"\"")
	w.WriteHeader(http.StatusOK)

	cw := csv.NewWriter(w)
	defer cw.Flush()

	_ = cw.Write([]string{
		"operation_date", "start_time", "end_time",
		"drone_name", "drone_model", "drone_serial", "drone_registration", "operator_number",
		"area_or_route", "max_altitude_agl_m",
		"remote_pilot", "certificate_ref",
		"category", "purpose", "logging_path", "fdr_log_url", "authorisation_ref",
		"weather", "airspace_ref", "observer", "incidents", "notes",
		"retention_until", "logbook_required", "compliance_flags",
	})

	for _, f := range list.Items {
		var d *droneRecord
		if dr, ok := drones[f.Drone]; ok {
			d = &dr
		}
		c := computeCompliance(f, d)
		droneName, model, serial, reg, opNo := "", "", "", "", ""
		if d != nil {
			droneName, model, serial = d.displayName(), d.Model, d.Serial
			reg, opNo = d.Registration, d.OperatorNumber
		}
		alt := ""
		if f.MaxAltitudeAGL > 0 {
			alt = strconv.FormatFloat(f.MaxAltitudeAGL, 'f', -1, 64)
		}
		_ = cw.Write([]string{
			day(f.OperationDate), f.StartTime, f.EndTime,
			droneName, model, serial, reg, opNo,
			f.AreaRoute, alt,
			f.PilotName, f.CertificateRef,
			f.Category, f.Purpose, c.LoggingPath, f.RawFDRLogURL, f.AuthorisationRef,
			f.Weather, f.AirspaceRef, f.Observer, f.Incidents, f.Notes,
			day(f.RetentionUntil), boolText(c.Required), strings.Join(c.RedFlags, "; "),
		})
	}
}

// day trims a PocketBase datetime string to its YYYY-MM-DD date.
func day(s string) string {
	if len(s) >= 10 {
		return s[:10]
	}
	return s
}

func boolText(b bool) string {
	if b {
		return "yes"
	}
	return "no"
}