// backend\operations.go

package main

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"strings"
	"time"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgconn"
)

type Operation struct {
	ID              string    `json:"id"`
	OperationNumber string    `json:"operationNumber"`
	OperationName   string    `json:"operationName"`
	Offense         string    `json:"offense"`
	CaseWorker      string    `json:"caseWorker"`
	TargetObject    string    `json:"targetObject"`
	KwAddress       string    `json:"kwAddress"`
	OperationLeader string    `json:"operationLeader"`
	OperationTeam   string    `json:"operationTeam"`
	Legend          string    `json:"legend"`
	Camera          string    `json:"camera"`
	Router          string    `json:"router"`
	Technology      string    `json:"technology"`
	Switchbox       string    `json:"switchbox"`
	HardDrive       string    `json:"hardDrive"`
	Laptop          string    `json:"laptop"`
	Remark          string    `json:"remark"`
	CreatedAt       time.Time `json:"createdAt"`
	UpdatedAt       time.Time `json:"updatedAt"`
}

type CreateOperationJournalEntryRequest struct {
	Content string `json:"content"`
}

type UpdateOperationJournalEntryRequest struct {
	Content string `json:"content"`
}

type CreateOperationRequest struct {
	OperationNumber string `json:"operationNumber"`
	OperationName   string `json:"operationName"`
	Offense         string `json:"offense"`
	CaseWorker      string `json:"caseWorker"`
	TargetObject    string `json:"targetObject"`
	KwAddress       string `json:"kwAddress"`
	OperationLeader string `json:"operationLeader"`
	OperationTeam   string `json:"operationTeam"`
	Legend          string `json:"legend"`
	Camera          string `json:"camera"`
	Router          string `json:"router"`
	Technology      string `json:"technology"`
	Switchbox       string `json:"switchbox"`
	HardDrive       string `json:"hardDrive"`
	Laptop          string `json:"laptop"`
	Remark          string `json:"remark"`
}

type UpdateOperationRequest = CreateOperationRequest

type OperationHistoryEntry struct {
	ID              string                   `json:"id"`
	OperationID     string                   `json:"operationId"`
	UserID          string                   `json:"userId"`
	UserDisplayName string                   `json:"userDisplayName"`
	Action          string                   `json:"action"`
	Changes         []OperationHistoryChange `json:"changes"`
	CreatedAt       time.Time                `json:"createdAt"`
	UpdatedAt       time.Time                `json:"updatedAt"`
	CanEdit         bool                     `json:"canEdit"`
}

type OperationHistoryChange struct {
	Field    string `json:"field"`
	Label    string `json:"label"`
	OldValue string `json:"oldValue"`
	NewValue string `json:"newValue"`
}

func (s *Server) handleOperations(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		s.handleListOperations(w, r)
	case http.MethodPost:
		s.handleCreateOperation(w, r)
	default:
		writeError(w, http.StatusMethodNotAllowed, "Method not allowed")
	}
}

func (s *Server) handleOperation(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodPut:
		s.handleUpdateOperation(w, r)
	default:
		writeError(w, http.StatusMethodNotAllowed, "Method not allowed")
	}
}

func (s *Server) handleListOperations(w http.ResponseWriter, r *http.Request) {
	rows, err := s.db.Query(
		r.Context(),
		`
		SELECT
			id,
			operation_number,
			operation_name,
			offense,
			case_worker,
			target_object,
			kw_address,
			operation_leader,
			operation_team,
			legend,
			camera,
			router,
			technology,
			switchbox,
			hard_drive,
			laptop,
			remark,
			created_at,
			updated_at
		FROM operations
		ORDER BY operation_number ASC
		`,
	)

	if err != nil {
		writeError(w, http.StatusInternalServerError, "Could not load operations")
		return
	}
	defer rows.Close()

	operations := []Operation{}

	for rows.Next() {
		var operation Operation

		if err := rows.Scan(
			&operation.ID,
			&operation.OperationNumber,
			&operation.OperationName,
			&operation.Offense,
			&operation.CaseWorker,
			&operation.TargetObject,
			&operation.KwAddress,
			&operation.OperationLeader,
			&operation.OperationTeam,
			&operation.Legend,
			&operation.Camera,
			&operation.Router,
			&operation.Technology,
			&operation.Switchbox,
			&operation.HardDrive,
			&operation.Laptop,
			&operation.Remark,
			&operation.CreatedAt,
			&operation.UpdatedAt,
		); err != nil {
			writeError(w, http.StatusInternalServerError, "Could not read operations")
			return
		}

		operations = append(operations, operation)
	}

	if err := rows.Err(); err != nil {
		writeError(w, http.StatusInternalServerError, "Could not read operations")
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{
		"operations": operations,
	})
}

func (s *Server) handleCreateOperation(w http.ResponseWriter, r *http.Request) {
	var input CreateOperationRequest

	if err := readJSON(r, &input); err != nil {
		writeError(w, http.StatusBadRequest, "Invalid JSON")
		return
	}

	normalizeOperationInput(&input)

	if input.OperationNumber == "" {
		writeError(w, http.StatusBadRequest, "Einsatznummer ist erforderlich")
		return
	}

	user, ok := userFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "Unauthorized")
		return
	}

	tx, err := s.db.Begin(r.Context())
	if err != nil {
		writeError(w, http.StatusInternalServerError, "Could not create operation")
		return
	}
	defer tx.Rollback(r.Context())

	var operation Operation

	err = tx.QueryRow(
		r.Context(),
		`
		INSERT INTO operations (
			operation_number,
			operation_name,
			offense,
			case_worker,
			target_object,
			kw_address,
			operation_leader,
			operation_team,
			legend,
			camera,
			router,
			technology,
			switchbox,
			hard_drive,
			laptop,
			remark
		)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16)
		RETURNING
			id,
			operation_number,
			operation_name,
			offense,
			case_worker,
			target_object,
			kw_address,
			operation_leader,
			operation_team,
			legend,
			camera,
			router,
			technology,
			switchbox,
			hard_drive,
			laptop,
			remark,
			created_at,
			updated_at
		`,
		input.OperationNumber,
		input.OperationName,
		input.Offense,
		input.CaseWorker,
		input.TargetObject,
		input.KwAddress,
		input.OperationLeader,
		input.OperationTeam,
		input.Legend,
		input.Camera,
		input.Router,
		input.Technology,
		input.Switchbox,
		input.HardDrive,
		input.Laptop,
		input.Remark,
	).Scan(
		&operation.ID,
		&operation.OperationNumber,
		&operation.OperationName,
		&operation.Offense,
		&operation.CaseWorker,
		&operation.TargetObject,
		&operation.KwAddress,
		&operation.OperationLeader,
		&operation.OperationTeam,
		&operation.Legend,
		&operation.Camera,
		&operation.Router,
		&operation.Technology,
		&operation.Switchbox,
		&operation.HardDrive,
		&operation.Laptop,
		&operation.Remark,
		&operation.CreatedAt,
		&operation.UpdatedAt,
	)

	if err != nil {
		var pgErr *pgconn.PgError

		if errors.As(err, &pgErr) && pgErr.Code == "23505" {
			writeError(w, http.StatusConflict, "Einsatz mit dieser Einsatznummer existiert bereits")
			return
		}

		writeError(w, http.StatusInternalServerError, "Could not create operation")
		return
	}

	changes := buildOperationCreateHistoryChanges(input)

	if err := recordOperationHistory(r.Context(), tx, operation.ID, user, "created", changes); err != nil {
		writeError(w, http.StatusInternalServerError, "Could not create operation history")
		return
	}

	if err := tx.Commit(r.Context()); err != nil {
		writeError(w, http.StatusInternalServerError, "Could not create operation")
		return
	}

	if err := s.createOperationNotification(
		r.Context(),
		user,
		operation,
		"operation.created",
		"Neuer Einsatz",
		fmt.Sprintf("Einsatz %s wurde erstellt.", operation.OperationNumber),
		map[string]any{
			"operationNumber": operation.OperationNumber,
			"operationName":   operation.OperationName,
		},
	); err != nil {
		// nicht abbrechen, Einsatz wurde bereits erstellt
	}

	writeJSON(w, http.StatusCreated, map[string]any{
		"operation": operation,
	})
}

func (s *Server) handleUpdateOperation(w http.ResponseWriter, r *http.Request) {
	operationID := strings.TrimSpace(r.PathValue("id"))

	if operationID == "" {
		writeError(w, http.StatusBadRequest, "Einsatz-ID fehlt")
		return
	}

	var input UpdateOperationRequest

	if err := readJSON(r, &input); err != nil {
		writeError(w, http.StatusBadRequest, "Invalid JSON")
		return
	}

	normalizeOperationInput(&input)

	if input.OperationNumber == "" {
		writeError(w, http.StatusBadRequest, "Einsatznummer ist erforderlich")
		return
	}

	user, ok := userFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "Unauthorized")
		return
	}

	tx, err := s.db.Begin(r.Context())
	if err != nil {
		writeError(w, http.StatusInternalServerError, "Could not update operation")
		return
	}
	defer tx.Rollback(r.Context())

	oldOperation, err := getOperationForHistory(r.Context(), tx, operationID)
	if errors.Is(err, pgx.ErrNoRows) {
		writeError(w, http.StatusNotFound, "Einsatz wurde nicht gefunden")
		return
	}

	if err != nil {
		writeError(w, http.StatusInternalServerError, "Could not load operation history state")
		return
	}

	var operation Operation

	err = tx.QueryRow(
		r.Context(),
		`
		UPDATE operations
		SET
			operation_number = $2,
			operation_name = $3,
			offense = $4,
			case_worker = $5,
			target_object = $6,
			kw_address = $7,
			operation_leader = $8,
			operation_team = $9,
			legend = $10,
			camera = $11,
			router = $12,
			technology = $13,
			switchbox = $14,
			hard_drive = $15,
			laptop = $16,
			remark = $17,
			updated_at = now()
		WHERE id = $1
		RETURNING
			id,
			operation_number,
			operation_name,
			offense,
			case_worker,
			target_object,
			kw_address,
			operation_leader,
			operation_team,
			legend,
			camera,
			router,
			technology,
			switchbox,
			hard_drive,
			laptop,
			remark,
			created_at,
			updated_at
		`,
		operationID,
		input.OperationNumber,
		input.OperationName,
		input.Offense,
		input.CaseWorker,
		input.TargetObject,
		input.KwAddress,
		input.OperationLeader,
		input.OperationTeam,
		input.Legend,
		input.Camera,
		input.Router,
		input.Technology,
		input.Switchbox,
		input.HardDrive,
		input.Laptop,
		input.Remark,
	).Scan(
		&operation.ID,
		&operation.OperationNumber,
		&operation.OperationName,
		&operation.Offense,
		&operation.CaseWorker,
		&operation.TargetObject,
		&operation.KwAddress,
		&operation.OperationLeader,
		&operation.OperationTeam,
		&operation.Legend,
		&operation.Camera,
		&operation.Router,
		&operation.Technology,
		&operation.Switchbox,
		&operation.HardDrive,
		&operation.Laptop,
		&operation.Remark,
		&operation.CreatedAt,
		&operation.UpdatedAt,
	)

	if errors.Is(err, pgx.ErrNoRows) {
		writeError(w, http.StatusNotFound, "Einsatz wurde nicht gefunden")
		return
	}

	if err != nil {
		var pgErr *pgconn.PgError

		if errors.As(err, &pgErr) && pgErr.Code == "23505" {
			writeError(w, http.StatusConflict, "Einsatz mit dieser Einsatznummer existiert bereits")
			return
		}

		writeError(w, http.StatusInternalServerError, "Could not update operation")
		return
	}

	changes := buildOperationUpdateHistoryChanges(oldOperation, input)

	if len(changes) > 0 {
		if err := recordOperationHistory(r.Context(), tx, operation.ID, user, "updated", changes); err != nil {
			writeError(w, http.StatusInternalServerError, "Could not create operation history")
			return
		}
	}

	if err := tx.Commit(r.Context()); err != nil {
		writeError(w, http.StatusInternalServerError, "Could not update operation")
		return
	}

	if err := s.createOperationNotification(
		r.Context(),
		user,
		operation,
		"operation.updated",
		"Einsatz geändert",
		fmt.Sprintf("Einsatz %s wurde geändert.", operation.OperationNumber),
		map[string]any{
			"operationNumber": operation.OperationNumber,
			"operationName":   operation.OperationName,
			"changes":         changes,
		},
	); err != nil {
		// nicht abbrechen, Änderung wurde bereits gespeichert
	}

	writeJSON(w, http.StatusOK, map[string]any{
		"operation": operation,
	})
}

func (s *Server) handleListOperationHistory(w http.ResponseWriter, r *http.Request) {
	operationID := strings.TrimSpace(r.PathValue("id"))

	if operationID == "" {
		writeError(w, http.StatusBadRequest, "Einsatz-ID fehlt")
		return
	}

	user, ok := userFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "Unauthorized")
		return
	}

	rows, err := s.db.Query(
		r.Context(),
		`
		SELECT
			h.id,
			h.operation_id,
			COALESCE(h.user_id::TEXT, ''),
			COALESCE(NULLIF(u.display_name, ''), NULLIF(u.username, ''), u.email, 'Unbekannt'),
			h.action,
			h.changes,
			h.created_at,
			h.updated_at
		FROM operation_history h
		LEFT JOIN users u ON u.id = h.user_id
		WHERE h.operation_id = $1
		ORDER BY h.created_at DESC
		`,
		operationID,
	)

	if err != nil {
		writeError(w, http.StatusInternalServerError, "Could not load operation history")
		return
	}
	defer rows.Close()

	history := []OperationHistoryEntry{}

	for rows.Next() {
		var entry OperationHistoryEntry
		var changesRaw []byte

		if err := rows.Scan(
			&entry.ID,
			&entry.OperationID,
			&entry.UserID,
			&entry.UserDisplayName,
			&entry.Action,
			&changesRaw,
			&entry.CreatedAt,
			&entry.UpdatedAt,
		); err != nil {
			writeError(w, http.StatusInternalServerError, "Could not read operation history")
			return
		}

		if len(changesRaw) > 0 {
			if err := json.Unmarshal(changesRaw, &entry.Changes); err != nil {
				writeError(w, http.StatusInternalServerError, "Could not parse operation history")
				return
			}
		}

		entry.CanEdit =
			entry.Action == "journal" &&
				entry.UserID == user.ID &&
				time.Since(entry.CreatedAt) <= 10*time.Minute

		history = append(history, entry)
	}

	if err := rows.Err(); err != nil {
		writeError(w, http.StatusInternalServerError, "Could not read operation history")
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{
		"history": history,
	})
}

func getOperationForHistory(ctx context.Context, tx pgx.Tx, operationID string) (Operation, error) {
	var operation Operation

	err := tx.QueryRow(
		ctx,
		`
		SELECT
			id,
			operation_number,
			operation_name,
			offense,
			case_worker,
			target_object,
			kw_address,
			operation_leader,
			operation_team,
			legend,
			camera,
			router,
			technology,
			switchbox,
			hard_drive,
			laptop,
			remark,
			created_at,
			updated_at
		FROM operations
		WHERE id = $1
		LIMIT 1
		`,
		operationID,
	).Scan(
		&operation.ID,
		&operation.OperationNumber,
		&operation.OperationName,
		&operation.Offense,
		&operation.CaseWorker,
		&operation.TargetObject,
		&operation.KwAddress,
		&operation.OperationLeader,
		&operation.OperationTeam,
		&operation.Legend,
		&operation.Camera,
		&operation.Router,
		&operation.Technology,
		&operation.Switchbox,
		&operation.HardDrive,
		&operation.Laptop,
		&operation.Remark,
		&operation.CreatedAt,
		&operation.UpdatedAt,
	)

	return operation, err
}

func recordOperationHistory(
	ctx context.Context,
	tx pgx.Tx,
	operationID string,
	user User,
	action string,
	changes []OperationHistoryChange,
) error {
	changesJSON, err := json.Marshal(changes)
	if err != nil {
		return err
	}

	_, err = tx.Exec(
		ctx,
		`
		INSERT INTO operation_history (
			operation_id,
			user_id,
			action,
			changes
		)
		VALUES ($1, $2, $3, $4::JSONB)
		`,
		operationID,
		user.ID,
		action,
		string(changesJSON),
	)

	return err
}

func buildOperationCreateHistoryChanges(input CreateOperationRequest) []OperationHistoryChange {
	changes := []OperationHistoryChange{}

	changes = appendOperationHistoryChange(changes, "operationNumber", "Einsatznummer", "", input.OperationNumber)
	changes = appendOperationHistoryChange(changes, "operationName", "Einsatzname", "", input.OperationName)
	changes = appendOperationHistoryChange(changes, "offense", "Delikt", "", input.Offense)
	changes = appendOperationHistoryChange(changes, "caseWorker", "Sachbearbeitung", "", input.CaseWorker)
	changes = appendOperationHistoryChange(changes, "targetObject", "Zielobjekt", "", input.TargetObject)
	changes = appendOperationHistoryChange(changes, "kwAddress", "KW", "", input.KwAddress)
	changes = appendOperationHistoryChange(changes, "operationLeader", "Einsatzleiter", "", input.OperationLeader)
	changes = appendOperationHistoryChange(changes, "operationTeam", "Einsatzteam", "", input.OperationTeam)
	changes = appendOperationHistoryChange(changes, "legend", "Legende", "", input.Legend)
	changes = appendOperationHistoryChange(changes, "camera", "Kamera", "", input.Camera)
	changes = appendOperationHistoryChange(changes, "router", "Router", "", input.Router)
	changes = appendOperationHistoryChange(changes, "technology", "Technik", "", input.Technology)
	changes = appendOperationHistoryChange(changes, "switchbox", "Switchbox", "", input.Switchbox)
	changes = appendOperationHistoryChange(changes, "hardDrive", "Festplatte", "", input.HardDrive)
	changes = appendOperationHistoryChange(changes, "laptop", "Laptop", "", input.Laptop)
	changes = appendOperationHistoryChange(changes, "remark", "Bemerkung", "", input.Remark)

	return changes
}

func buildOperationUpdateHistoryChanges(oldOperation Operation, input UpdateOperationRequest) []OperationHistoryChange {
	changes := []OperationHistoryChange{}

	changes = appendOperationHistoryChange(changes, "operationNumber", "Einsatznummer", oldOperation.OperationNumber, input.OperationNumber)
	changes = appendOperationHistoryChange(changes, "operationName", "Einsatzname", oldOperation.OperationName, input.OperationName)
	changes = appendOperationHistoryChange(changes, "offense", "Delikt", oldOperation.Offense, input.Offense)
	changes = appendOperationHistoryChange(changes, "caseWorker", "Sachbearbeitung", oldOperation.CaseWorker, input.CaseWorker)
	changes = appendOperationHistoryChange(changes, "targetObject", "Zielobjekt", oldOperation.TargetObject, input.TargetObject)
	changes = appendOperationHistoryChange(changes, "kwAddress", "KW", oldOperation.KwAddress, input.KwAddress)
	changes = appendOperationHistoryChange(changes, "operationLeader", "Einsatzleiter", oldOperation.OperationLeader, input.OperationLeader)
	changes = appendOperationHistoryChange(changes, "operationTeam", "Einsatzteam", oldOperation.OperationTeam, input.OperationTeam)
	changes = appendOperationHistoryChange(changes, "legend", "Legende", oldOperation.Legend, input.Legend)
	changes = appendOperationHistoryChange(changes, "camera", "Kamera", oldOperation.Camera, input.Camera)
	changes = appendOperationHistoryChange(changes, "router", "Router", oldOperation.Router, input.Router)
	changes = appendOperationHistoryChange(changes, "technology", "Technik", oldOperation.Technology, input.Technology)
	changes = appendOperationHistoryChange(changes, "switchbox", "Switchbox", oldOperation.Switchbox, input.Switchbox)
	changes = appendOperationHistoryChange(changes, "hardDrive", "Festplatte", oldOperation.HardDrive, input.HardDrive)
	changes = appendOperationHistoryChange(changes, "laptop", "Laptop", oldOperation.Laptop, input.Laptop)
	changes = appendOperationHistoryChange(changes, "remark", "Bemerkung", oldOperation.Remark, input.Remark)

	return changes
}

func appendOperationHistoryChange(
	changes []OperationHistoryChange,
	field string,
	label string,
	oldValue string,
	newValue string,
) []OperationHistoryChange {
	oldValue = strings.TrimSpace(oldValue)
	newValue = strings.TrimSpace(newValue)

	if oldValue == newValue {
		return changes
	}

	return append(changes, OperationHistoryChange{
		Field:    field,
		Label:    label,
		OldValue: displayHistoryValue(oldValue),
		NewValue: displayHistoryValue(newValue),
	})
}

func normalizeOperationInput(input *CreateOperationRequest) {
	input.OperationNumber = strings.TrimSpace(input.OperationNumber)
	input.OperationName = strings.TrimSpace(input.OperationName)
	input.Offense = strings.TrimSpace(input.Offense)
	input.CaseWorker = strings.TrimSpace(input.CaseWorker)
	input.TargetObject = strings.TrimSpace(input.TargetObject)
	input.KwAddress = strings.TrimSpace(input.KwAddress)
	input.OperationLeader = strings.TrimSpace(input.OperationLeader)
	input.OperationTeam = strings.TrimSpace(input.OperationTeam)
	input.Legend = strings.TrimSpace(input.Legend)
	input.Camera = strings.TrimSpace(input.Camera)
	input.Router = strings.TrimSpace(input.Router)
	input.Technology = strings.TrimSpace(input.Technology)
	input.Switchbox = strings.TrimSpace(input.Switchbox)
	input.HardDrive = strings.TrimSpace(input.HardDrive)
	input.Laptop = strings.TrimSpace(input.Laptop)
	input.Remark = strings.TrimSpace(input.Remark)
}

func (s *Server) handleCreateOperationJournalEntry(w http.ResponseWriter, r *http.Request) {
	operationID := strings.TrimSpace(r.PathValue("id"))

	if operationID == "" {
		writeError(w, http.StatusBadRequest, "Einsatz-ID fehlt")
		return
	}

	var input CreateOperationJournalEntryRequest

	if err := readJSON(r, &input); err != nil {
		writeError(w, http.StatusBadRequest, "Invalid JSON")
		return
	}

	content := strings.TrimSpace(input.Content)

	if content == "" {
		writeError(w, http.StatusBadRequest, "Journal-Eintrag darf nicht leer sein")
		return
	}

	user, ok := userFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "Unauthorized")
		return
	}

	tx, err := s.db.Begin(r.Context())
	if err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Eintrag konnte nicht erstellt werden")
		return
	}
	defer tx.Rollback(r.Context())

	operation, err := getOperationForHistory(r.Context(), tx, operationID)
	if errors.Is(err, pgx.ErrNoRows) {
		writeError(w, http.StatusNotFound, "Einsatz wurde nicht gefunden")
		return
	}

	if err != nil {
		writeError(w, http.StatusInternalServerError, "Einsatz konnte nicht geladen werden")
		return
	}

	changes := []OperationHistoryChange{
		{
			Field:    "journal",
			Label:    "Journal",
			OldValue: "",
			NewValue: content,
		},
	}

	if err := recordOperationHistory(r.Context(), tx, operation.ID, user, "journal", changes); err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Eintrag konnte nicht gespeichert werden")
		return
	}

	if err := tx.Commit(r.Context()); err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Eintrag konnte nicht gespeichert werden")
		return
	}

	_ = s.createOperationJournalEvent(
		r.Context(),
		user,
		operation,
		map[string]any{
			"operationNumber": operation.OperationNumber,
			"operationName":   operation.OperationName,
		},
	)

	writeJSON(w, http.StatusCreated, map[string]any{
		"ok": true,
	})
}

func (s *Server) handleUpdateOperationJournalEntry(w http.ResponseWriter, r *http.Request) {
	operationID := strings.TrimSpace(r.PathValue("id"))
	historyID := strings.TrimSpace(r.PathValue("historyId"))

	if operationID == "" {
		writeError(w, http.StatusBadRequest, "Einsatz-ID fehlt")
		return
	}

	if historyID == "" {
		writeError(w, http.StatusBadRequest, "Journal-ID fehlt")
		return
	}

	var input UpdateOperationJournalEntryRequest

	if err := readJSON(r, &input); err != nil {
		writeError(w, http.StatusBadRequest, "Invalid JSON")
		return
	}

	content := strings.TrimSpace(input.Content)

	if content == "" {
		writeError(w, http.StatusBadRequest, "Journal-Eintrag darf nicht leer sein")
		return
	}

	user, ok := userFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "Unauthorized")
		return
	}

	tx, err := s.db.Begin(r.Context())
	if err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Eintrag konnte nicht gespeichert werden")
		return
	}
	defer tx.Rollback(r.Context())

	operation, err := getOperationForHistory(r.Context(), tx, operationID)
	if errors.Is(err, pgx.ErrNoRows) {
		writeError(w, http.StatusNotFound, "Einsatz wurde nicht gefunden")
		return
	}

	if err != nil {
		writeError(w, http.StatusInternalServerError, "Einsatz konnte nicht geladen werden")
		return
	}

	var changesRaw []byte
	var createdAt time.Time

	err = tx.QueryRow(
		r.Context(),
		`
		SELECT changes, created_at
		FROM operation_history
		WHERE id = $1
		  AND operation_id = $2
		  AND user_id = $3
		  AND action = 'journal'
		LIMIT 1
		`,
		historyID,
		operationID,
		user.ID,
	).Scan(&changesRaw, &createdAt)

	if errors.Is(err, pgx.ErrNoRows) {
		writeError(w, http.StatusNotFound, "Journal-Eintrag wurde nicht gefunden oder darf nicht bearbeitet werden")
		return
	}

	if err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Eintrag konnte nicht geladen werden")
		return
	}

	if time.Since(createdAt) > 10*time.Minute {
		writeError(w, http.StatusForbidden, "Journal-Eintrag kann nur innerhalb von 10 Minuten bearbeitet werden")
		return
	}

	var oldChanges []OperationHistoryChange

	if len(changesRaw) > 0 {
		if err := json.Unmarshal(changesRaw, &oldChanges); err != nil {
			writeError(w, http.StatusInternalServerError, "Journal-Eintrag konnte nicht gelesen werden")
			return
		}
	}

	oldContent := ""

	for _, change := range oldChanges {
		if change.Field == "journal" {
			oldContent = change.NewValue
			break
		}
	}

	if strings.TrimSpace(oldContent) == content {
		writeJSON(w, http.StatusOK, map[string]any{
			"ok": true,
		})
		return
	}

	changes := []OperationHistoryChange{
		{
			Field:    "journal",
			Label:    "Journal",
			OldValue: oldContent,
			NewValue: content,
		},
	}

	changesJSON, err := json.Marshal(changes)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Eintrag konnte nicht vorbereitet werden")
		return
	}

	commandTag, err := tx.Exec(
		r.Context(),
		`
		UPDATE operation_history
		SET
			changes = $4::JSONB,
			updated_at = now()
		WHERE id = $1
		  AND operation_id = $2
		  AND user_id = $3
		  AND action = 'journal'
		  AND created_at >= now() - interval '10 minutes'
		`,
		historyID,
		operationID,
		user.ID,
		string(changesJSON),
	)

	if err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Eintrag konnte nicht gespeichert werden")
		return
	}

	if commandTag.RowsAffected() == 0 {
		writeError(w, http.StatusForbidden, "Journal-Eintrag kann nicht mehr bearbeitet werden")
		return
	}

	if err := tx.Commit(r.Context()); err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Eintrag konnte nicht gespeichert werden")
		return
	}

	_ = s.createOperationJournalEvent(
		r.Context(),
		user,
		operation,
		map[string]any{
			"operationNumber": operation.OperationNumber,
			"operationName":   operation.OperationName,
			"historyId":       historyID,
			"action":          "updated",
		},
	)

	writeJSON(w, http.StatusOK, map[string]any{
		"ok": true,
	})
}

func (s *Server) handleListUnreadOperationJournals(w http.ResponseWriter, r *http.Request) {
	user, ok := userFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "Unauthorized")
		return
	}

	rows, err := s.db.Query(
		r.Context(),
		`
		SELECT entity_id::TEXT
		FROM notifications
		WHERE user_id = $1
		  AND visible = false
		  AND type = 'operation.journal'
		  AND entity_type = 'operation'
		  AND entity_id IS NOT NULL
		  AND read_at IS NULL
		GROUP BY entity_id
		`,
		user.ID,
	)

	if err != nil {
		writeError(w, http.StatusInternalServerError, "Ungelesene Journal-Einträge konnten nicht geladen werden")
		return
	}
	defer rows.Close()

	operationIds := []string{}

	for rows.Next() {
		var operationID string
		if err := rows.Scan(&operationID); err != nil {
			writeError(w, http.StatusInternalServerError, "Ungelesene Journal-Einträge konnten nicht gelesen werden")
			return
		}

		operationIds = append(operationIds, operationID)
	}

	writeJSON(w, http.StatusOK, map[string]any{
		"operationIds": operationIds,
	})
}

func (s *Server) handleMarkOperationJournalRead(w http.ResponseWriter, r *http.Request) {
	user, ok := userFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "Unauthorized")
		return
	}

	operationID := strings.TrimSpace(r.PathValue("id"))
	if operationID == "" {
		writeError(w, http.StatusBadRequest, "Einsatz-ID fehlt")
		return
	}

	_, err := s.db.Exec(
		r.Context(),
		`
		UPDATE notifications
		SET read_at = COALESCE(read_at, now())
		WHERE user_id = $1
		  AND visible = false
		  AND type = 'operation.journal'
		  AND entity_type = 'operation'
		  AND entity_id = $2
		  AND read_at IS NULL
		`,
		user.ID,
		operationID,
	)

	if err != nil {
		writeError(w, http.StatusInternalServerError, "Journal-Status konnte nicht aktualisiert werden")
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{
		"ok": true,
	})
}