package com.android.trisolarisserver.controller

import com.android.trisolarisserver.component.DocumentStorage
import com.android.trisolarisserver.component.DocumentTokenService
import com.android.trisolarisserver.component.ExtractionQueue
import com.android.trisolarisserver.component.GuestDocumentEvents
import com.android.trisolarisserver.component.DocumentExtractionService
import com.android.trisolarisserver.component.PropertyAccess
import com.android.trisolarisserver.db.repo.BookingRepo
import com.android.trisolarisserver.db.repo.GuestDocumentRepo
import com.android.trisolarisserver.db.repo.GuestRepo
import com.android.trisolarisserver.models.booking.GuestDocument
import com.android.trisolarisserver.models.property.Role
import com.android.trisolarisserver.repo.AppUserRepo
import com.android.trisolarisserver.repo.PropertyRepo
import com.android.trisolarisserver.security.MyPrincipal
import com.fasterxml.jackson.databind.ObjectMapper
import org.springframework.core.io.FileSystemResource
import org.springframework.http.HttpHeaders
import org.springframework.http.HttpStatus
import org.springframework.http.ResponseEntity
import org.springframework.security.core.annotation.AuthenticationPrincipal
import org.springframework.transaction.annotation.Transactional
import org.springframework.web.bind.annotation.*
import org.springframework.http.MediaType
import jakarta.servlet.http.HttpServletResponse
import org.springframework.web.multipart.MultipartFile
import org.springframework.web.server.ResponseStatusException
import java.time.OffsetDateTime
import java.nio.file.Files
import java.nio.file.Paths
import java.util.UUID
import java.security.MessageDigest

@RestController
@RequestMapping("/properties/{propertyId}/guests/{guestId}/documents")
class GuestDocuments(
    private val propertyAccess: PropertyAccess,
    private val propertyRepo: PropertyRepo,
    private val guestRepo: GuestRepo,
    private val bookingRepo: BookingRepo,
    private val guestDocumentRepo: GuestDocumentRepo,
    private val appUserRepo: AppUserRepo,
    private val storage: DocumentStorage,
    private val tokenService: DocumentTokenService,
    private val extractionQueue: ExtractionQueue,
    private val guestDocumentEvents: GuestDocumentEvents,
    private val extractionService: DocumentExtractionService,
    private val objectMapper: ObjectMapper,
    @org.springframework.beans.factory.annotation.Value("\${storage.documents.publicBaseUrl}")
    private val publicBaseUrl: String,
    @org.springframework.beans.factory.annotation.Value("\${storage.documents.aiBaseUrl:\${storage.documents.publicBaseUrl}}")
    private val aiBaseUrl: String
) {

    @PostMapping
    @ResponseStatus(HttpStatus.CREATED)
    fun uploadDocument(
        @PathVariable propertyId: UUID,
        @PathVariable guestId: UUID,
        @AuthenticationPrincipal principal: MyPrincipal?,
        @RequestParam("bookingId") bookingId: UUID,
        @RequestPart("file") file: MultipartFile
    ): GuestDocumentResponse {
        val user = requireUser(appUserRepo, principal)
        propertyAccess.requireMember(propertyId, user.id!!)
        propertyAccess.requireAnyRole(propertyId, user.id!!, Role.ADMIN, Role.MANAGER)

        if (file.isEmpty) {
            throw ResponseStatusException(HttpStatus.BAD_REQUEST, "File is empty")
        }
        val contentType = file.contentType
        if (contentType != null && contentType.startsWith("video/")) {
            throw ResponseStatusException(HttpStatus.BAD_REQUEST, "Video files are not allowed")
        }

        val (property, guest) = requirePropertyGuest(propertyRepo, guestRepo, propertyId, guestId)
        val booking = bookingRepo.findById(bookingId).orElseThrow {
            ResponseStatusException(HttpStatus.NOT_FOUND, "Booking not found")
        }
        if (booking.property.id != propertyId) {
            throw ResponseStatusException(HttpStatus.BAD_REQUEST, "Booking not in property")
        }
        if (booking.primaryGuest?.id != guestId) {
            throw ResponseStatusException(HttpStatus.BAD_REQUEST, "Booking not linked to guest")
        }

        val stored = storage.store(propertyId, guestId, bookingId, file)
        val fileHash = hashFile(stored.storagePath)
        if (fileHash != null && guestDocumentRepo.existsByPropertyIdAndGuestIdAndBookingIdAndFileHash(
                propertyId,
                guestId,
                bookingId,
                fileHash
            )
        ) {
            Files.deleteIfExists(Paths.get(stored.storagePath))
            throw ResponseStatusException(HttpStatus.CONFLICT, "Duplicate document")
        }
        val document = GuestDocument(
            property = property,
            guest = guest,
            booking = booking,
            uploadedBy = user,
            originalFilename = stored.originalFilename,
            contentType = stored.contentType,
            sizeBytes = stored.sizeBytes,
            storagePath = stored.storagePath,
            fileHash = fileHash
        )
        val saved = guestDocumentRepo.save(document)
        runExtraction(saved.id!!, propertyId, guestId)
        guestDocumentEvents.emit(propertyId, guestId)
        return saved.toResponse(objectMapper)
    }

    @GetMapping
    fun listDocuments(
        @PathVariable propertyId: UUID,
        @PathVariable guestId: UUID,
        @AuthenticationPrincipal principal: MyPrincipal?
    ): List<GuestDocumentResponse> {
        requireRole(propertyAccess, propertyId, principal, Role.ADMIN, Role.MANAGER)

        return guestDocumentRepo
            .findByPropertyIdAndGuestIdOrderByUploadedAtDesc(propertyId, guestId)
            .map { it.toResponse(objectMapper) }
    }

    @GetMapping("/stream", produces = [MediaType.TEXT_EVENT_STREAM_VALUE])
    fun streamDocuments(
        @PathVariable propertyId: UUID,
        @PathVariable guestId: UUID,
        @AuthenticationPrincipal principal: MyPrincipal?,
        response: HttpServletResponse
    ): org.springframework.web.servlet.mvc.method.annotation.SseEmitter {
        requireRole(propertyAccess, propertyId, principal, Role.ADMIN, Role.MANAGER)
        response.setHeader("Cache-Control", "no-cache")
        response.setHeader("X-Accel-Buffering", "no")
        return guestDocumentEvents.subscribe(propertyId, guestId)
    }

    @GetMapping("/{documentId}/file")
    fun downloadDocument(
        @PathVariable propertyId: UUID,
        @PathVariable guestId: UUID,
        @PathVariable documentId: UUID,
        @RequestParam(required = false) token: String?,
        @AuthenticationPrincipal principal: MyPrincipal?
    ): ResponseEntity<FileSystemResource> {
        if (token == null) {
            requireRole(propertyAccess, propertyId, principal, Role.ADMIN, Role.MANAGER)
        } else if (!tokenService.validateToken(token, documentId.toString())) {
            throw ResponseStatusException(HttpStatus.UNAUTHORIZED, "Invalid token")
        }

        val document = guestDocumentRepo.findByIdAndPropertyIdAndGuestId(documentId, propertyId, guestId)
            ?: throw ResponseStatusException(HttpStatus.NOT_FOUND, "Document not found")

        val path = Paths.get(document.storagePath)
        if (!Files.exists(path)) {
            throw ResponseStatusException(HttpStatus.NOT_FOUND, "File missing")
        }
        val resource = FileSystemResource(path)
        val type = document.contentType ?: MediaType.APPLICATION_OCTET_STREAM_VALUE
        return ResponseEntity.ok()
            .contentType(MediaType.parseMediaType(type))
            .header(HttpHeaders.CONTENT_DISPOSITION, "inline; filename=\"${document.originalFilename}\"")
            .contentLength(document.sizeBytes)
            .body(resource)
    }

    @DeleteMapping("/{documentId}")
    @ResponseStatus(HttpStatus.NO_CONTENT)
    @Transactional
    fun deleteDocument(
        @PathVariable propertyId: UUID,
        @PathVariable guestId: UUID,
        @PathVariable documentId: UUID,
        @AuthenticationPrincipal principal: MyPrincipal?
    ) {
        requireRole(propertyAccess, propertyId, principal, Role.ADMIN, Role.MANAGER)

        val document = guestDocumentRepo.findByIdAndPropertyIdAndGuestId(documentId, propertyId, guestId)
            ?: throw ResponseStatusException(HttpStatus.NOT_FOUND, "Document not found")
        val status = document.booking.status
        if (status != com.android.trisolarisserver.models.booking.BookingStatus.OPEN &&
            status != com.android.trisolarisserver.models.booking.BookingStatus.CHECKED_IN
        ) {
            throw ResponseStatusException(
                HttpStatus.BAD_REQUEST,
                "Documents can only be deleted for OPEN or CHECKED_IN bookings"
            )
        }

        val path = Paths.get(document.storagePath)
        try {
            Files.deleteIfExists(path)
        } catch (_: Exception) {
            throw ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "Failed to delete file")
        }
        guestDocumentRepo.delete(document)
        guestDocumentEvents.emit(propertyId, guestId)
    }

    private fun runExtraction(documentId: UUID, propertyId: UUID, guestId: UUID) {
        extractionQueue.enqueue {
            val document = guestDocumentRepo.findById(documentId).orElse(null) ?: return@enqueue
            try {
                val token = tokenService.createToken(document.id.toString())
                val imageUrl =
                    "${aiBaseUrl}/properties/$propertyId/guests/$guestId/documents/${document.id}/file?token=$token"

                val publicImageUrl =
                    "${publicBaseUrl.trimEnd('/')}/properties/$propertyId/guests/$guestId/documents/${document.id}/file?token=$token"
                val extraction = extractionService.extractAndApply(imageUrl, publicImageUrl, document, propertyId)
                val results = extraction.results

                document.extractedData = objectMapper.writeValueAsString(results)
                document.extractedAt = OffsetDateTime.now()
                guestDocumentRepo.save(document)
                guestDocumentEvents.emit(propertyId, guestId)
            } catch (_: Exception) {
                // Keep upload successful even if AI extraction fails.
            }
        }
    }

    private fun hashFile(storagePath: String): String? {
        return try {
            val path = Paths.get(storagePath)
            if (!Files.exists(path)) return null
            val digest = MessageDigest.getInstance("SHA-256")
            Files.newInputStream(path).use { input ->
                val buffer = ByteArray(DEFAULT_BUFFER_SIZE)
                var read = input.read(buffer)
                while (read >= 0) {
                    if (read > 0) {
                        digest.update(buffer, 0, read)
                    }
                    read = input.read(buffer)
                }
            }
            digest.digest().joinToString("") { "%02x".format(it) }
        } catch (_: Exception) {
            null
        }
    }
}