/*
    * Copyright (C) 2024 B3Partners B.V.
    *
    * SPDX-License-Identifier: MIT
    */
   package org.tailormap.api.controller.admin;
   
   import static java.net.HttpURLConnection.HTTP_ACCEPTED;
   import static java.net.HttpURLConnection.HTTP_BAD_REQUEST;
  import static java.net.HttpURLConnection.HTTP_NOT_FOUND;
  
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.node.ObjectNode;
  import io.swagger.v3.oas.annotations.Operation;
  import io.swagger.v3.oas.annotations.media.Content;
  import io.swagger.v3.oas.annotations.media.Schema;
  import io.swagger.v3.oas.annotations.responses.ApiResponse;
  import java.lang.invoke.MethodHandles;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Objects;
  import java.util.UUID;
  import org.quartz.CronTrigger;
  import org.quartz.InterruptableJob;
  import org.quartz.JobDataMap;
  import org.quartz.JobDetail;
  import org.quartz.JobKey;
  import org.quartz.Scheduler;
  import org.quartz.SchedulerException;
  import org.quartz.Trigger;
  import org.quartz.TriggerKey;
  import org.quartz.TriggerUtils;
  import org.quartz.impl.matchers.GroupMatcher;
  import org.quartz.spi.OperableTrigger;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.http.HttpStatus;
  import org.springframework.http.HttpStatusCode;
  import org.springframework.http.MediaType;
  import org.springframework.http.ResponseEntity;
  import org.springframework.web.bind.annotation.DeleteMapping;
  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.PathVariable;
  import org.springframework.web.bind.annotation.PutMapping;
  import org.springframework.web.bind.annotation.RequestParam;
  import org.springframework.web.bind.annotation.RestController;
  import org.springframework.web.server.ResponseStatusException;
  import org.tailormap.api.repository.SearchIndexRepository;
  import org.tailormap.api.scheduling.Task;
  import org.tailormap.api.scheduling.TaskManagerService;
  import org.tailormap.api.scheduling.TaskType;
  
  /**
   * Admin controller for controlling the task scheduler. Not to be used to create new tasks, adding tasks belongs in the
   * domain of the specific controller or Spring Data REST API as that requires specific configuration information.
   * Provides the following endpoints:
   *
   * <ul>
   *   <li>{@link #list /admin/tasks} to list all tasks, optionally filtered by type
   *   <li>{@link #details /admin/tasks/{type}/{uuid}} to get the details of a task
   *   <li>{@link #startTask /admin/tasks/{type}/{uuid}/start} to start a task
   *   <li>{@link #stopTask /admin/tasks/{type}/{uuid}/stop} to stop a task
   *   <li>{@link #delete /admin/tasks/{type}/{uuid}} to delete a task
   * </ul>
   */
  @RestController
  public class TaskAdminController {
    private static final Logger logger =
        LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
    private final Scheduler scheduler;
    private final TaskManagerService taskManagerService;
    private final SearchIndexRepository searchIndexRepository;
  
    public TaskAdminController(
        @Autowired Scheduler scheduler,
        @Autowired TaskManagerService taskManagerService,
        @Autowired SearchIndexRepository searchIndexRepository) {
      this.scheduler = scheduler;
      this.taskManagerService = taskManagerService;
      this.searchIndexRepository = searchIndexRepository;
    }
  
    @Operation(summary = "List all tasks, optionally filtered by type", description = """
  This will return a list of all tasks, optionally filtered by task type.
  The state of the task is one of the Quartz Trigger states.
  The state can be one of: NONE, NORMAL, PAUSED, COMPLETE, ERROR, BLOCKED or null in error conditions.
  """)
    @GetMapping(path = "${tailormap-api.admin.base-path}/tasks", produces = MediaType.APPLICATION_JSON_VALUE)
    @ApiResponse(
        responseCode = "200",
        description = "List of all tasks, this list may be empty",
        content = @Content(mediaType = MediaType.APPLICATION_JSON_VALUE, schema = @Schema(example = """
  {"tasks":[
  {"uuid":"6308d26e-fe1e-4268-bb28-20db2cd06914","type":"index", "state":"NORMAL", "interruptable": false},
  {"uuid":"d5ce9152-e90e-4b5a-b129-3b2366cabca8","type":"poc", "state": "BLOCKED", "interruptable": false},
  {"uuid":"d5ce9152-e90e-4b5a-b129-3b2366cabca9","type":"poc", "state": "PAUSED", "interruptable": false},
  {"uuid":"d5ce9152-e90e-4b5a-b129-3b2366cabca2","type":"poc", "state": "COMPLETE", "interruptable": false},
 {"uuid":"d5ce9152-e90e-4b5a-b129-3b2366cabca3","type":"interuptablepoc", "state": "ERROR", "interruptable": true}
 ]}
 """)))
   public ResponseEntity<Object> list(@RequestParam(required = false) String type) throws ResponseStatusException {
     logger.debug("Listing all tasks (optional type filter: {})", (null == type ? "all" : type));
     final List<ObjectNode> tasks = new ArrayList<>();
 
     final GroupMatcher<JobKey> groupMatcher =
         (null == type ? GroupMatcher.anyGroup() : GroupMatcher.groupEquals(type));
     try {
       scheduler.getJobKeys(groupMatcher).stream()
           .map(jobKey -> {
             try {
               return scheduler.getJobDetail(jobKey);
             } catch (SchedulerException e) {
               logger.error("Error getting task detail", e);
               return null;
             }
           })
           .filter(Objects::nonNull)
           .forEach(jobDetail -> {
             Trigger.TriggerState state;
             try {
               state = scheduler.getTriggerState(TriggerKey.triggerKey(
                   jobDetail.getKey().getName(),
                   jobDetail.getKey().getGroup()));
             } catch (SchedulerException e) {
               logger.error("Error getting task state", e);
               state = null;
             }
             tasks.add(new ObjectMapper()
                 .createObjectNode()
                 .put(Task.TYPE_KEY, jobDetail.getKey().getGroup())
                 .put(Task.UUID_KEY, jobDetail.getKey().getName())
                 .put(
                     Task.INTERRUPTABLE_KEY,
                     InterruptableJob.class.isAssignableFrom(jobDetail.getJobClass()))
                 .put(
                     Task.DESCRIPTION_KEY,
                     jobDetail.getJobDataMap().getString(Task.DESCRIPTION_KEY))
                 .put(
                     Task.LAST_RESULT_KEY,
                     jobDetail.getJobDataMap().getString(Task.LAST_RESULT_KEY))
                 .putPOJO(Task.STATE_KEY, state));
           });
     } catch (SchedulerException e) {
       throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "Error getting tasks", e);
     }
 
     return ResponseEntity.ok(new ObjectMapper()
         .createObjectNode()
         .set("tasks", new ObjectMapper().createArrayNode().addAll(tasks)));
   }
 
   @Operation(summary = "List all details for a given task", description = """
 This will return the details of the task, including the status, progress,
 result and any other information.
 """)
   @GetMapping(
       path = "${tailormap-api.admin.base-path}/tasks/{type}/{uuid}",
       produces = MediaType.APPLICATION_JSON_VALUE)
   @ApiResponse(
       responseCode = "404",
       description = "Task not found",
       content =
           @Content(
               mediaType = MediaType.APPLICATION_JSON_VALUE,
               schema = @Schema(example = "{\"message\":\"Task not found\",\"code\":404}")))
   @ApiResponse(
       responseCode = "200",
       description = """
 Details of the task. The response content will vay according to the type of task,
 the most common fields are listed in the Task interface.
 """,
       content = @Content(mediaType = MediaType.APPLICATION_JSON_VALUE, schema = @Schema(example = """
 {
 "type":"poc",
 "uuid":"6308d26e-fe1e-4268-bb28-20db2cd06914",
 "interruptable":false,
 "description":"This is a poc task",
 "startTime":"2024-06-06T12:00:00Z",
 "nextTime":"2024-06-06T12:00:00Z",
 "state":"NORMAL",
 "progress":"...",
 "result":"...",
 "message":"something is happening"
 "jobData":{ "type":"poc", "description":"This is a poc task" }
 }
 """)))
   public ResponseEntity<Object> details(@PathVariable TaskType type, @PathVariable UUID uuid)
       throws ResponseStatusException {
     logger.debug("Getting task details for {}:{}", type, uuid);
 
     try {
       JobKey jobKey = taskManagerService.getJobKey(type, uuid);
       if (null == jobKey) {
         return handleTaskNotFound();
       }
 
       JobDetail jobDetail = scheduler.getJobDetail(jobKey);
       JobDataMap jobDataMap = jobDetail.getJobDataMap();
 
       /* there should be only one */
       Trigger trigger = scheduler.getTriggersOfJob(jobDetail.getKey()).getFirst();
       CronTrigger cron = ((CronTrigger) trigger);
 
       final Object[] result = new Object[1];
       scheduler.getCurrentlyExecutingJobs().stream()
           .filter(Objects::nonNull)
           .filter(jobExecutionContext ->
               jobExecutionContext.getJobDetail().getKey().equals(jobKey))
           .forEach(jobExecutionContext -> {
             logger.debug(
                 "currently executing job {} with trigger {}.",
                 jobExecutionContext.getJobDetail().getKey(),
                 jobExecutionContext.getTrigger().getKey());
 
             result[0] = jobExecutionContext.getResult();
           });
 
       return ResponseEntity.ok(new ObjectMapper()
           .createObjectNode()
           // immutable uuid, type and description
           .put(Task.TYPE_KEY, jobDetail.getKey().getGroup())
           .put(Task.UUID_KEY, jobDetail.getKey().getName())
           .put(Task.INTERRUPTABLE_KEY, InterruptableJob.class.isAssignableFrom(jobDetail.getJobClass()))
           .put(Task.DESCRIPTION_KEY, jobDataMap.getString(Task.DESCRIPTION_KEY))
           .put(Task.CRON_EXPRESSION_KEY, cron.getCronExpression())
           // TODO / XXX we could add a human-readable description of the cron expression using
           // eg.
           //   com.cronutils:cron-utils like:
           //     CronParser cronParser = new
           //         CronParser(CronDefinitionBuilder.instanceDefinitionFor(QUARTZ));
           //     CronDescriptor.instance(locale).describe(cronParser.parse(cronExpression));
           //   this could also be done front-end using eg.
           // https://www.npmjs.com/package/cronstrue
           //   which has the advantage of knowing the required locale for the human
           // .put("cronDescription", cron.getCronExpression())
           .put("timezone", cron.getTimeZone().getID())
           .putPOJO("startTime", trigger.getStartTime())
           .putPOJO("lastTime", trigger.getPreviousFireTime())
           .putPOJO("nextFireTimes", TriggerUtils.computeFireTimes((OperableTrigger) cron, null, 5))
           .putPOJO(Task.STATE_KEY, scheduler.getTriggerState(trigger.getKey()))
           .putPOJO("progress", result[0])
           .put(Task.LAST_RESULT_KEY, jobDataMap.getString(Task.LAST_RESULT_KEY))
           .putPOJO("jobData", jobDataMap));
     } catch (SchedulerException e) {
       throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "Error getting task", e);
     }
   }
 
   @Operation(summary = "Start a task", description = "This will start the task if it is not already running")
   @PutMapping(
       path = "${tailormap-api.admin.base-path}/tasks/{type}/{uuid}/start",
       produces = MediaType.APPLICATION_JSON_VALUE)
   @ApiResponse(
       responseCode = "404",
       description = "Task not found",
       content =
           @Content(
               mediaType = MediaType.APPLICATION_JSON_VALUE,
               schema = @Schema(example = "{\"message\":\"Task not found\",\"code\":404}")))
   @ApiResponse(
       responseCode = "202",
       description = "Task is started",
       content =
           @Content(
               mediaType = MediaType.APPLICATION_JSON_VALUE,
               schema = @Schema(example = "{\"message\":\"Task starting accepted\",\"code\":202}")))
   public ResponseEntity<Object> startTask(@PathVariable TaskType type, @PathVariable UUID uuid)
       throws ResponseStatusException {
     logger.debug("Starting task {}:{}", type, uuid);
 
     try {
       JobKey jobKey = taskManagerService.getJobKey(type, uuid);
       if (null == jobKey) {
         return handleTaskNotFound();
       }
       scheduler.triggerJob(jobKey);
       return ResponseEntity.status(HttpStatusCode.valueOf(HTTP_ACCEPTED))
           .body(new ObjectMapper().createObjectNode().put("message", "Task starting accepted"));
 
     } catch (SchedulerException e) {
       throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "Error getting task", e);
     }
   }
 
   @Operation(summary = "Stop a task irrevocably", description = """
 This will stop a running task, if the task is not running, nothing will happen.
 This can leave the application in an inconsistent state.
 A task that is not interruptable cannot be stopped.
 A stopped task cannot be restarted, it fire again depending on the schedule.
 """)
   @PutMapping(
       path = "${tailormap-api.admin.base-path}/tasks/{type}/{uuid}/stop",
       produces = MediaType.APPLICATION_JSON_VALUE)
   @ApiResponse(
       responseCode = "404",
       description = "Task not found",
       content =
           @Content(
               mediaType = MediaType.APPLICATION_JSON_VALUE,
               schema = @Schema(example = "{\"message\":\"Task not found\", \"code\":404}")))
   @ApiResponse(
       responseCode = "202",
       description = "Task is stopping",
       content = @Content(mediaType = MediaType.APPLICATION_JSON_VALUE, schema = @Schema(example = """
 {
 "message":"Task stopping accepted".
 "succes":true
 }
 """)))
   @ApiResponse(
       responseCode = "400",
       description = "The task cannot be stopped as it does not implement the InterruptableJob interface.",
       content = @Content(mediaType = MediaType.APPLICATION_JSON_VALUE, schema = @Schema(example = """
 { "message":"Task cannot be stopped" }
 """)))
   public ResponseEntity<Object> stopTask(@PathVariable TaskType type, @PathVariable UUID uuid)
       throws ResponseStatusException {
     logger.debug("Stopping task {}:{}", type, uuid);
 
     try {
       JobKey jobKey = taskManagerService.getJobKey(type, uuid);
       if (null == jobKey) {
         return handleTaskNotFound();
       }
 
       if (InterruptableJob.class.isAssignableFrom(
           scheduler.getJobDetail(jobKey).getJobClass())) {
         boolean interrupted = scheduler.interrupt(jobKey);
         return ResponseEntity.status(HttpStatusCode.valueOf(HTTP_ACCEPTED))
             .body(new ObjectMapper()
                 .createObjectNode()
                 .put("message", "Task stopping accepted")
                 .put("succes", interrupted));
       } else {
         return ResponseEntity.status(HttpStatusCode.valueOf(HTTP_BAD_REQUEST))
             .body(new ObjectMapper()
                 .createObjectNode()
                 .put("message", "Task cannot be stopped")
                 .put("succes", false));
       }
 
     } catch (SchedulerException e) {
       throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "Error getting task", e);
     }
   }
 
   @Operation(
       summary = "Delete a task",
       description = "This will remove the task from the scheduler and delete all information about the task")
   @DeleteMapping(
       path = "${tailormap-api.admin.base-path}/tasks/{type}/{uuid}",
       produces = MediaType.APPLICATION_JSON_VALUE)
   @ApiResponse(
       responseCode = "404",
       description = "Task not found",
       content =
           @Content(
               mediaType = MediaType.APPLICATION_JSON_VALUE,
               schema = @Schema(example = "{\"message\":\"Task not found\"}")))
   @ApiResponse(responseCode = "204", description = "Task is deleted")
   public ResponseEntity<Object> delete(@PathVariable TaskType type, @PathVariable UUID uuid)
       throws ResponseStatusException {
 
     try {
       JobKey jobKey = taskManagerService.getJobKey(type, uuid);
       if (null == jobKey) {
         return handleTaskNotFound();
       }
 
       boolean succes = scheduler.deleteJob(jobKey);
       logger.info("Task {}:{} deletion {}", type, uuid, (succes ? "succeeded" : "failed"));
       // cleanup the schedule from the business objects
       switch (type) {
         case INDEX:
           deleteScheduleFromSearchIndex(uuid);
           break;
         case PROMETHEUS_PING:
         // no action required, as these are not managed in Tailormap
         default:
           break;
       }
       return ResponseEntity.noContent().build();
     } catch (SchedulerException e) {
       throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "Error getting task", e);
     }
   }
 
   private void deleteScheduleFromSearchIndex(UUID uuid) {
     searchIndexRepository.findByTaskScheduleUuid(uuid).forEach(searchIndex -> {
       searchIndex.setSchedule(null);
       searchIndexRepository.save(searchIndex);
     });
   }
 
   private ResponseEntity<Object> handleTaskNotFound() {
     return ResponseEntity.status(HttpStatusCode.valueOf(HTTP_NOT_FOUND))
         .contentType(MediaType.APPLICATION_JSON)
         .body(new ObjectMapper()
             .createObjectNode()
             .put("message", "Task not found")
             .put("code", HTTP_NOT_FOUND));
   }
 }