package handlers

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"io"
	"log"
	"net/http"
	"strings"

	"github.com/google/uuid"

	"git.georgsen.dk/hwlab/internal/ai"
	"git.georgsen.dk/hwlab/internal/inventory"
	"git.georgsen.dk/hwlab/internal/labels"
	"git.georgsen.dk/hwlab/internal/netbox"
	"git.georgsen.dk/hwlab/internal/printer"
	"git.georgsen.dk/hwlab/internal/queue"
)

// IntakeOrchestrator is the subset of ai.Orchestrator the intake handler needs.
// Using an interface allows tests to inject a mock without depending on the concrete type.
type IntakeOrchestrator interface {
	Analyze(ctx context.Context, req ai.IntakeRequest) (*ai.IntakeResult, inventory.CatalogStatus, error)
}

// IntakeNetBoxClient is the subset of netbox.Client the intake handler needs.
type IntakeNetBoxClient interface {
	AllocateNextHWID(ctx context.Context) (string, error)
	CreateDevice(ctx context.Context, name, assetTag string, deviceTypeID, roleID, siteID int32) (int64, error)
	PatchCustomFields(ctx context.Context, deviceID int64, patch map[string]interface{}) error
	SyncTags(ctx context.Context, tags []string) ([]netbox.TagRef, error)
}

// IntakeCatalogUpdater is the subset needed for catalog status persistence.
type IntakeCatalogUpdater interface {
	UpdateCatalogStatus(ctx context.Context, deviceID int64, current, next inventory.CatalogStatus) (inventory.CatalogStatus, error)
}

// IntakeWAQ is the subset of WAQ the handler needs.
type IntakeWAQ interface {
	Enqueue(ctx context.Context, op queue.PendingOp) error
}

// IntakePrinter is the optional printer used to auto-print a label after intake.
// If nil, label printing is skipped. Printer errors are non-fatal.
type IntakePrinter interface {
	Print(bitmap []byte, width, height int) error
}

// IntakeHandler handles POST /api/intake — multipart photo upload → AI analysis →
// HW-ID allocation → NetBox record creation (or WAQ enqueue on NetBox failure).
type IntakeHandler struct {
	orchestrator    IntakeOrchestrator
	netboxClient    IntakeNetBoxClient
	catalogUpdater  IntakeCatalogUpdater
	waq             IntakeWAQ     // may be nil if DragonFlyDB unavailable
	printer         IntakePrinter // may be nil; auto-print is optional
	deviceTypeID    int32
	roleID          int32
	siteID          int32
	quickAddEnabled bool
	quickAddThresh  float64
}

// NewIntakeHandler constructs an IntakeHandler. waq and p may be nil.
func NewIntakeHandler(
	orch IntakeOrchestrator,
	nb IntakeNetBoxClient,
	cu IntakeCatalogUpdater,
	waq IntakeWAQ,
	deviceTypeID, roleID, siteID int32,
	quickAddEnabled bool,
	quickAddThresh float64,
	p IntakePrinter, // may be nil — label printing will be skipped
) *IntakeHandler {
	return &IntakeHandler{
		orchestrator:    orch,
		netboxClient:    nb,
		catalogUpdater:  cu,
		waq:             waq,
		printer:         p,
		deviceTypeID:    deviceTypeID,
		roleID:          roleID,
		siteID:          siteID,
		quickAddEnabled: quickAddEnabled,
		quickAddThresh:  quickAddThresh,
	}
}

// IntakeResponse is the JSON body returned by POST /api/intake.
type IntakeResponse struct {
	HWID          string            `json:"hw_id"`
	Model         string            `json:"model"`
	Manufacturer  string            `json:"manufacturer"`
	Category      string            `json:"category"`
	Specs         map[string]string `json:"specs"`
	SuggestedTags []string          `json:"suggested_tags"`
	AINotes       string            `json:"ai_notes"`
	Confidence    float64           `json:"confidence"`
	CatalogStatus string            `json:"catalog_status"`
	NetBoxID      int64             `json:"netbox_id,omitempty"`
	Queued        bool              `json:"queued,omitempty"`        // true if NetBox was unreachable
	PrintSkipped  bool              `json:"print_skipped,omitempty"` // true if label was not printed
}

// ServeHTTP implements http.Handler for the intake endpoint.
//
// Flow:
//  1. Parse multipart form (32 MB limit)
//  2. Validate 1–3 photo files → 400 on violation
//  3. Base64-encode photos → orchestrator.Analyze
//  4. AllocateNextHWID
//  5. CreateDevice in NetBox (or enqueue to WAQ on failure → 202)
//  6. PatchCustomFields, SyncTags, UpdateCatalogStatus
//  7. Return 201 IntakeResponse
func (h *IntakeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	// T-02-09: 32 MB hard cap on request body (DoS mitigation)
	if err := r.ParseMultipartForm(32 << 20); err != nil {
		http.Error(w, "invalid multipart form", http.StatusBadRequest)
		return
	}

	files := r.MultipartForm.File["photos"]

	// T-02-12: Explicit count check — 0 or 4+ photos rejected immediately
	if len(files) == 0 {
		http.Error(w, "at least 1 photo required", http.StatusBadRequest)
		return
	}
	if len(files) > 3 {
		http.Error(w, "maximum 3 photos allowed", http.StatusBadRequest)
		return
	}

	// Read and base64-encode each photo
	photosBase64 := make([]string, 0, len(files))
	for _, fh := range files {
		f, err := fh.Open()
		if err != nil {
			http.Error(w, "could not read photo", http.StatusInternalServerError)
			return
		}
		data, err := io.ReadAll(f)
		f.Close()
		if err != nil {
			http.Error(w, "could not read photo data", http.StatusInternalServerError)
			return
		}
		// Detect MIME type from first 512 bytes
		mimeType := http.DetectContentType(data)
		encoded := "data:" + mimeType + ";base64," + base64.StdEncoding.EncodeToString(data)
		photosBase64 = append(photosBase64, encoded)
	}

	jobID := uuid.New().String()
	result, status, err := h.orchestrator.Analyze(r.Context(), ai.IntakeRequest{
		PhotosBase64: photosBase64,
		JobID:        jobID,
	})
	if err != nil {
		log.Printf("intake: orchestrator error for job %s: %v", jobID, err)
		http.Error(w, "AI analysis failed", http.StatusInternalServerError)
		return
	}

	hwid, err := h.netboxClient.AllocateNextHWID(r.Context())
	if err != nil {
		log.Printf("intake: HW-ID allocation error: %v", err)
		http.Error(w, "HW-ID allocation failed", http.StatusInternalServerError)
		return
	}

	// Build device name from AI result
	deviceName := strings.TrimSpace(result.Manufacturer + " " + result.Model)
	if deviceName == "" {
		deviceName = hwid
	}

	// Attempt NetBox record creation
	// Both quick-add and standard paths call CreateDevice.
	// Quick-add path: proceed only when confidence meets threshold.
	// Standard path: always attempt (review step is a UI concern, not handler concern).
	deviceID, createErr := h.netboxClient.CreateDevice(
		r.Context(),
		deviceName,
		hwid,
		h.deviceTypeID,
		h.roleID,
		h.siteID,
	)

	if createErr != nil {
		log.Printf("intake: NetBox CreateDevice error: %v", createErr)
		// Enqueue to WAQ if available
		if h.waq != nil {
			payload, _ := json.Marshal(queue.CreateDevicePayload{
				Name:         deviceName,
				AssetTag:     hwid,
				DeviceTypeID: h.deviceTypeID,
				RoleID:       h.roleID,
				SiteID:       h.siteID,
			})
			op, err := queue.NewPendingOp(queue.OpNetBoxCreateDevice, json.RawMessage(payload))
			if err == nil {
				if enqErr := h.waq.Enqueue(r.Context(), op); enqErr != nil {
					log.Printf("intake: WAQ enqueue error: %v", enqErr)
				}
			}
			writeJSON(w, http.StatusAccepted, IntakeResponse{
				HWID:          hwid,
				Model:         result.Model,
				Manufacturer:  result.Manufacturer,
				Category:      result.Category,
				Specs:         result.Specs,
				SuggestedTags: result.SuggestedTags,
				AINotes:       result.AINotes,
				Confidence:    result.Confidence,
				CatalogStatus: string(status),
				Queued:        true,
			})
			return
		}
		// WAQ unavailable — cannot queue
		http.Error(w, "NetBox unavailable and WAQ not configured", http.StatusServiceUnavailable)
		return
	}

	// NetBox create succeeded — patch custom fields, sync tags, update catalog status
	cf := netbox.CustomFields{
		HWID:          hwid,
		CatalogStatus: string(status),
		AINotes:       result.AINotes,
	}
	patch := netbox.BuildFullCustomFieldsPatch(cf)
	if err := h.netboxClient.PatchCustomFields(r.Context(), deviceID, patch); err != nil {
		log.Printf("intake: PatchCustomFields error for device %d: %v", deviceID, err)
		// Non-fatal — proceed with partial data
	}

	if len(result.SuggestedTags) > 0 {
		if _, err := h.netboxClient.SyncTags(r.Context(), result.SuggestedTags); err != nil {
			log.Printf("intake: SyncTags error for device %d: %v", deviceID, err)
			// Non-fatal
		}
	}

	if _, err := h.catalogUpdater.UpdateCatalogStatus(r.Context(), deviceID, "", status); err != nil {
		log.Printf("intake: UpdateCatalogStatus error for device %d: %v", deviceID, err)
		// Non-fatal
	}

	// Auto-print label (non-fatal: printer errors skip printing but don't fail intake).
	// T-04-13: print called once per intake, synchronous, within its own error boundary.
	printSkipped := true
	if h.printer != nil {
		labelData := labels.LabelData{
			HWID:     hwid,
			Name:     strings.TrimSpace(result.Manufacturer + " " + result.Model),
			SpecLine: result.AINotes, // AINotes is the best single-line summary available
		}
		if labelData.Name == "" {
			labelData.Name = hwid
		}
		img, renderErr := labels.RenderStandard(labelData)
		if renderErr == nil {
			bitmap, bmpW, bmpH := printer.ImageToRawBitmap(img)
			if printErr := h.printer.Print(bitmap, bmpW, bmpH); printErr == nil {
				printSkipped = false
			} else {
				log.Printf("intake: auto-print skipped: %v", printErr)
			}
		} else {
			log.Printf("intake: label render failed: %v", renderErr)
		}
	}

	writeJSON(w, http.StatusCreated, IntakeResponse{
		HWID:          hwid,
		Model:         result.Model,
		Manufacturer:  result.Manufacturer,
		Category:      result.Category,
		Specs:         result.Specs,
		SuggestedTags: result.SuggestedTags,
		AINotes:       result.AINotes,
		Confidence:    result.Confidence,
		CatalogStatus: string(status),
		NetBoxID:      deviceID,
		PrintSkipped:  printSkipped,
	})
}

// writeJSON writes a JSON response with the given status code.
func writeJSON(w http.ResponseWriter, status int, v interface{}) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	if err := json.NewEncoder(w).Encode(v); err != nil {
		log.Printf("writeJSON: encode error: %v", err)
	}
}