package api

import (
	"errors"
	"fmt"
	"net/http"

	"printer.backend/internal/model"
	"printer.backend/internal/platepdf"
	"printer.backend/internal/store"
)

func registerPDFRoutes(mux *http.ServeMux, configs *store.ConfigurationStore, plates *store.PlateStore, items *store.ItemStore) {
	mux.HandleFunc("GET /layout/pdf", layoutPDF(plates, items))
	mux.HandleFunc("GET /configurations/{id}/pdf", configurationPDF(configs, plates, items))
}

func layoutPDF(plates *store.PlateStore, items *store.ItemStore) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		plateID := r.URL.Query().Get("plate_id")
		itemID := r.URL.Query().Get("item_id")
		if plateID == "" || itemID == "" {
			writeError(w, http.StatusBadRequest, errors.New("plate_id and item_id query params are required"))
			return
		}
		spacing, err := parseSpacing(r.URL.Query().Get("spacing_mm"))
		if err != nil {
			writeError(w, http.StatusBadRequest, err)
			return
		}

		plate, item, preview, svgPath, err := resolveLayoutPDF(plates, items, plateID, itemID, spacing)
		if err != nil {
			writeError(w, http.StatusBadRequest, err)
			return
		}

		pdf, err := platepdf.Generate(plate, item.Spec, svgPath, preview)
		if err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		servePDF(w, pdf, "layout-preview.pdf")
	}
}

func configurationPDF(configs *store.ConfigurationStore, plates *store.PlateStore, items *store.ItemStore) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		id := r.PathValue("id")
		c, err := configs.Get(id)
		if err != nil {
			writeError(w, http.StatusNotFound, err)
			return
		}

		plate, item, preview, svgPath, err := resolveLayoutPDF(plates, items, c.PlateID, c.ItemID, c.SpacingMM)
		if err != nil {
			writeError(w, http.StatusBadRequest, err)
			return
		}

		pdf, err := platepdf.Generate(plate, item.Spec, svgPath, preview)
		if err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		name := c.Name
		if name == "" {
			name = "configuration-" + id[:8]
		}
		servePDF(w, pdf, sanitizeFilename(name)+".pdf")
	}
}

func resolveLayoutPDF(plates *store.PlateStore, items *store.ItemStore, plateID, itemID string, spacingMM float64) (
	plate model.Plate, item model.Item, preview model.LayoutPreview, svgPath string, err error,
) {
	plate, err = findPlate(plates, plateID)
	if err != nil {
		return plate, item, preview, "", err
	}
	item, err = items.Get(itemID)
	if err != nil {
		return plate, item, preview, "", err
	}
	svgPath, err = items.SVGPath(itemID)
	if err != nil {
		return plate, item, preview, "", err
	}
	preview, err = buildPreview(plates, items, plateID, itemID, spacingMM)
	if err != nil {
		return plate, item, preview, "", err
	}
	preview.PlateID = plateID
	preview.ItemID = itemID
	return plate, item, preview, svgPath, nil
}

func servePDF(w http.ResponseWriter, pdf []byte, filename string) {
	w.Header().Set("Content-Type", "application/pdf")
	w.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename="%s"`, filename))
	w.Header().Set("Cache-Control", "no-cache")
	_, _ = w.Write(pdf)
}

func sanitizeFilename(name string) string {
	var b []byte
	for i := 0; i < len(name); i++ {
		c := name[i]
		if (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || c == '-' || c == '_' {
			b = append(b, c)
		} else if c == ' ' {
			b = append(b, '_')
		}
	}
	if len(b) == 0 {
		return "preview"
	}
	return string(b)
}