package it.inaf.ia2.gms.controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.opencsv.CSVWriter;
import it.inaf.ia2.gms.manager.GroupStatusManager;
import it.inaf.ia2.gms.manager.GroupsManager;
import it.inaf.ia2.gms.model.request.AddGroupRequest;
import it.inaf.ia2.gms.model.GroupNode;
import it.inaf.ia2.gms.model.response.PaginatedData;
import it.inaf.ia2.gms.model.request.PaginatedModelRequest;
import it.inaf.ia2.gms.model.request.DeleteGroupRequest;
import it.inaf.ia2.gms.model.request.GroupsRequest;
import it.inaf.ia2.gms.model.request.RenameGroupRequest;
import it.inaf.ia2.gms.model.request.SearchFilterRequest;
import it.inaf.ia2.gms.persistence.model.GroupEntity;
import it.inaf.ia2.gms.service.GroupNameService;
import it.inaf.ia2.gms.service.GroupsService;
import it.inaf.ia2.gms.service.GroupsTreeBuilder;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.security.Principal;
import java.util.List;
import java.util.Optional;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.validation.Valid;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
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.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class GroupsController {

    private static final ObjectMapper MAPPER = new ObjectMapper();

    @Autowired
    private HttpServletRequest servletRequest;

    @Autowired
    private GroupsManager groupsManager;

    @Autowired
    private GroupsService groupsService;

    @Autowired
    private GroupsTreeBuilder groupsTreeBuilder;

    @Autowired
    private GroupsTabResponseBuilder groupsTabResponseBuilder;

    @Autowired
    private GroupStatusManager groupStatusManager;

    @Autowired
    protected GroupNameService groupNameService;

    @GetMapping(value = "/groups", produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<?> getGroupsTab(@Valid GroupsRequest request) {
        if (request.isOnlyPanel()) {
            // Only groupsPanel
            GroupEntity group = groupsManager.getGroupById(request.getGroupId());
            return ResponseEntity.ok(getGroupsPanel(group, request));
        } else {
            // Complete GroupsTabResponse
            return ResponseEntity.ok(groupsTabResponseBuilder.getGroupsTab(request));
        }
    }

    @PostMapping(value = "/group", consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<PaginatedData<GroupNode>> createGroup(@Valid @RequestBody AddGroupRequest request) {

        GroupEntity parent = groupsManager.getGroupById(request.getParentGroupId());

        groupsManager.createGroup(parent, request.getNewGroupName(), request.isLeaf());

        PaginatedData<GroupNode> groupsPanel = getGroupsPanel(parent, request);

        return new ResponseEntity<>(groupsPanel, HttpStatus.CREATED);
    }

    @PutMapping(value = "/group/{groupId}", consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<PaginatedData<GroupNode>> updateGroup(@PathVariable("groupId") String groupId, @Valid @RequestBody RenameGroupRequest request) {

        GroupEntity updatedGroup = groupsManager.updateGroup(groupId, request.getNewGroupName(), request.isLeaf());

        GroupEntity parent = groupsManager.getGroupByPath(updatedGroup.getParentPath());

        PaginatedData<GroupNode> groupsPanel = getGroupsPanel(parent, request);

        return ResponseEntity.ok(groupsPanel);
    }

    @DeleteMapping(value = "/group/{groupId}", produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<?> deleteGroup(@PathVariable("groupId") String groupId, DeleteGroupRequest request) {

        GroupEntity parent = groupsManager.deleteGroup(groupId);
        PaginatedData<GroupNode> groupsPanel = getGroupsPanel(parent, request);

        return ResponseEntity.ok(groupsPanel);
    }

    @GetMapping(value = "/group/status", produces = {MediaType.APPLICATION_OCTET_STREAM_VALUE, MediaType.APPLICATION_JSON_VALUE})
    public void downloadStatus(@RequestParam(value = "groupId", required = false) String groupId,
            @RequestParam(value = "groupName", required = false) String groupName,
            HttpServletRequest request, HttpServletResponse response) throws Exception {

        if (groupId == null && groupName == null) {
            response.sendError(400, "Parameter groupId or groupName is required");
            return;
        }

        if (groupId == null) {
            GroupEntity group = groupNameService.getGroupFromNames(Optional.of(groupName));
            groupId = group.getId();
        }

        List<String[]> status = groupStatusManager.generateStatus(groupId);

        try ( OutputStream out = response.getOutputStream()) {

            if ("application/json".equals(request.getHeader("Accept"))) {
                MAPPER.writeValue(out, status);
            } else {
                try ( CSVWriter writer = new CSVWriter(new OutputStreamWriter(out))) {
                    writer.writeNext(new String[]{"program", "email"});

                    for (String[] row : status) {
                        writer.writeNext(row);
                    }
                }
            }
        }
    }

    private <T extends PaginatedModelRequest & SearchFilterRequest> PaginatedData<GroupNode> getGroupsPanel(GroupEntity parentGroup, T request) {
        return groupsTreeBuilder.listSubGroups(parentGroup, request, servletRequest.getUserPrincipal().getName());
    }

    @GetMapping(value = "/groups", produces = MediaType.TEXT_PLAIN_VALUE)
    public void listChildGroups(@RequestParam("parent") Optional<String> groupNames,
            @RequestParam(value = "recursive", defaultValue = "false") boolean recursive,
            Principal principal, HttpServletResponse response) throws IOException {

        GroupEntity parentGroup = groupNameService.getGroupFromNames(groupNames);

        List<GroupEntity> visibleSubgroups = groupsManager.getChildGroups(parentGroup, recursive);

        try ( PrintWriter pw = new PrintWriter(response.getOutputStream())) {
            for (String groupName : groupNameService.getGroupsNames(visibleSubgroups)) {
                pw.println(groupNameService.getShortGroupName(groupName, groupNames));
            }
        }
    }

    /**
     * Creates a group and its ancestors if they are missing. It doesn't fail if
     * the last group already exists. For CLI/API usage.
     */
    @PostMapping(value = "/group", produces = MediaType.TEXT_PLAIN_VALUE, consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
    public void createGroup(@RequestParam("name") String groupParam,
            @RequestParam(value = "leaf", required = false, defaultValue = "false") boolean leaf,
            HttpServletResponse response) throws IOException {

        List<String> groupNames = groupNameService.extractGroupNames(groupParam);

        GroupEntity group = groupsManager.getRoot();
        for (int i = 0; i < groupNames.size(); i++) {
            String name = groupNames.get(i);
            Optional<GroupEntity> optGroup = groupsService.findGroupByParentAndName(group, name);
            if (optGroup.isPresent()) {
                group = optGroup.get();
            } else {
                group = groupsManager.createGroup(group, name, i == groupNames.size() - 1 ? leaf : false);
            }
        }

        response.setStatus(HttpServletResponse.SC_CREATED);
        try ( PrintWriter pw = new PrintWriter(response.getOutputStream())) {
            pw.println(groupParam);
        }
    }

    @DeleteMapping(value = "/group", produces = MediaType.TEXT_PLAIN_VALUE)
    public ResponseEntity<?> deleteGroup(@RequestParam("name") String groupParam) {
        GroupEntity group = groupNameService.getGroupFromNames(Optional.of(groupParam));
        groupsManager.deleteGroup(group.getId());
        return ResponseEntity.noContent().build();
    }
}