package com.aiteacher.book;

import com.aiteacher.document.FigureEntity;
import com.aiteacher.document.FigureRepository;
import com.aiteacher.document.MarkdownStorageService;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.UUID;

@RestController
@RequestMapping("/api/v1/books")
public class BookController {

    private final BookService bookService;
    private final FigureRepository figureRepository;
    private final MarkdownStorageService markdownStorageService;

    @Value("${app.features.upload-enabled:true}")
    private boolean uploadEnabled;

    @Value("${app.features.delete-enabled:true}")
    private boolean deleteEnabled;

    public BookController(BookService bookService, FigureRepository figureRepository,
                          MarkdownStorageService markdownStorageService) {
        this.bookService = bookService;
        this.figureRepository = figureRepository;
        this.markdownStorageService = markdownStorageService;
    }

    @PostMapping(consumes = "multipart/form-data")
    public ResponseEntity<?> upload(@RequestParam("file") MultipartFile file) throws IOException {
        if (!uploadEnabled) return ResponseEntity.status(HttpStatus.METHOD_NOT_ALLOWED).build();
        Book book = bookService.upload(file);
        return ResponseEntity.status(HttpStatus.ACCEPTED).body(toSummaryResponse(book));
    }

    @GetMapping
    public ResponseEntity<List<Map<String, Object>>> list() {
        List<Map<String, Object>> books = bookService.listAll().stream()
            .map(this::toFullResponse)
            .toList();
        return ResponseEntity.ok(books);
    }

    @GetMapping("/{id}")
    public ResponseEntity<Map<String, Object>> get(@PathVariable UUID id) {
        Book book = bookService.getById(id);
        return ResponseEntity.ok(toFullResponse(book));
    }

    @DeleteMapping("/{id}")
    public ResponseEntity<Void> delete(@PathVariable UUID id) {
        if (!deleteEnabled) return ResponseEntity.status(HttpStatus.METHOD_NOT_ALLOWED).build();
        bookService.delete(id);
        return ResponseEntity.noContent().build();
    }

    @PostMapping("/{id}/reembed")
    public ResponseEntity<Map<String, Object>> reembed(@PathVariable UUID id) {
        Book book = bookService.reembed(id);
        return ResponseEntity.accepted().body(Map.of(
            "bookId", book.getId(),
            "status", BookStatus.PROCESSING.name()
        ));
    }

    @GetMapping(value = "/{id}/pages/{pageNumber}/html", produces = MediaType.TEXT_HTML_VALUE)
    public ResponseEntity<String> getPageHtml(@PathVariable UUID id,
                                               @PathVariable int pageNumber) {
        bookService.getById(id); // 404 if not found
        try {
            return ResponseEntity.ok(markdownStorageService.getText(id, pageNumber));
        } catch (Exception e) {
            return ResponseEntity.notFound().build();
        }
    }

    @GetMapping("/{id}/figures")
    public ResponseEntity<List<FigureResponse>> figures(@PathVariable UUID id) {
        bookService.getById(id); // 404 if not found
        List<FigureResponse> responses = figureRepository.findAllByBookId(id)
            .stream()
            .map(f -> toFigureResponse(id, f))
            .toList();
        return ResponseEntity.ok(responses);
    }

    private FigureResponse toFigureResponse(UUID bookId, FigureEntity f) {
        String filename = f.getImagePath().substring(f.getImagePath().lastIndexOf('/') + 1);
        String imageUrl = "/api/v1/figures/" + bookId + "/" + filename;
        return new FigureResponse(
            f.getId(), f.getLabel(), f.getCaption(),
            f.getFigureType().name(), f.getPage(), imageUrl,
            f.getSectionId(),
            null // section title not eagerly loaded here
        );
    }

    private Map<String, Object> toSummaryResponse(Book book) {
        return Map.of(
            "id", book.getId(),
            "title", book.getTitle(),
            "fileName", book.getFileName(),
            "status", book.getStatus().name(),
            "uploadedAt", book.getUploadedAt()
        );
    }

    private Map<String, Object> toFullResponse(Book book) {
        var map = new java.util.LinkedHashMap<String, Object>();
        map.put("id", book.getId());
        map.put("title", book.getTitle());
        map.put("fileName", book.getFileName());
        map.put("fileSizeBytes", book.getFileSizeBytes());
        map.put("pageCount", book.getPageCount());
        map.put("status", book.getStatus().name());
        map.put("uploadedAt", book.getUploadedAt());
        map.put("processedAt", book.getProcessedAt());
        if (book.getErrorMessage() != null) {
            map.put("errorMessage", book.getErrorMessage());
        }
        return map;
    }
}