package api

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"

	"git.pengzhan.dev/haopengzhan/rsspipe/internal/models"
	"github.com/go-chi/chi/v5"
)

// Category Handlers
func (h *Handler) ListCategories(w http.ResponseWriter, r *http.Request) {
	cats, err := h.feedService.ListCategories(r.Context())
	if err != nil {
		h.writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	if cats == nil {
		cats = []models.Category{}
	}
	h.writeJSON(w, http.StatusOK, cats)
}

func (h *Handler) CreateCategory(w http.ResponseWriter, r *http.Request) {
	var body struct {
		Title    string  `json:"title"`
		ParentID *string `json:"parent_id,omitempty"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || strings.TrimSpace(body.Title) == "" {
		h.writeError(w, http.StatusBadRequest, "valid category title is required")
		return
	}

	cat, err := h.feedService.CreateCategory(r.Context(), strings.TrimSpace(body.Title), body.ParentID)
	if err != nil {
		h.writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	h.writeJSON(w, http.StatusCreated, cat)
}

func (h *Handler) DeleteCategory(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if err := h.feedService.DeleteCategory(r.Context(), id); err != nil {
		h.writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	h.writeJSON(w, http.StatusOK, map[string]string{"message": "category deleted"})
}

// Feed Handlers
func (h *Handler) ListFeeds(w http.ResponseWriter, r *http.Request) {
	feeds, err := h.feedService.ListFeeds(r.Context())
	if err != nil {
		h.writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	if feeds == nil {
		feeds = []models.Feed{}
	}
	h.writeJSON(w, http.StatusOK, feeds)
}

func (h *Handler) CreateFeed(w http.ResponseWriter, r *http.Request) {
	var req models.CreateFeedRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil || strings.TrimSpace(req.FeedURL) == "" {
		h.writeError(w, http.StatusBadRequest, "valid feed_url is required")
		return
	}

	feed, err := h.feedService.CreateFeed(r.Context(), req)
	if err != nil {
		h.writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	h.writeJSON(w, http.StatusCreated, feed)
}

func (h *Handler) UpdateFeed(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	var req models.UpdateFeedRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		h.writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	feed, err := h.feedService.UpdateFeed(r.Context(), id, req)
	if err != nil {
		h.writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	h.writeJSON(w, http.StatusOK, feed)
}

func (h *Handler) DeleteFeed(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if err := h.feedService.DeleteFeed(r.Context(), id); err != nil {
		h.writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	h.writeJSON(w, http.StatusOK, map[string]string{"message": "feed deleted"})
}

func (h *Handler) RefreshFeed(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	f, err := h.feedService.RefreshFeed(r.Context(), id)
	if err != nil {
		h.writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	h.writeJSON(w, http.StatusOK, f)
}

func (h *Handler) RefreshAllFeeds(w http.ResponseWriter, r *http.Request) {
	h.feedService.RefreshAllFeeds(r.Context())
	h.writeJSON(w, http.StatusAccepted, map[string]string{"message": "refreshing all feeds in background"})
}

func (h *Handler) GetStats(w http.ResponseWriter, r *http.Request) {
	stats, err := h.feedService.GetStats(r.Context())
	if err != nil {
		h.writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	h.writeJSON(w, http.StatusOK, stats)
}

// OPML Handlers
func (h *Handler) ImportOPML(w http.ResponseWriter, r *http.Request) {
	if err := r.ParseMultipartForm(10 << 20); err != nil {
		h.writeError(w, http.StatusBadRequest, "failed to parse multipart form")
		return
	}

	file, _, err := r.FormFile("file")
	if err != nil {
		h.writeError(w, http.StatusBadRequest, "file field is required")
		return
	}
	defer func() {
		_ = file.Close()
	}()

	data, err := io.ReadAll(file)
	if err != nil {
		h.writeError(w, http.StatusBadRequest, "failed to read file")
		return
	}

	createdCount, totalParsed, err := h.feedService.ImportOPML(r.Context(), data)
	if err != nil {
		h.writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	h.writeJSON(w, http.StatusOK, map[string]interface{}{
		"imported_count": createdCount,
		"total_parsed":   totalParsed,
	})
}

func (h *Handler) ExportOPML(w http.ResponseWriter, r *http.Request) {
	xmlData, err := h.feedService.ExportOPML(r.Context())
	if err != nil {
		h.writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	w.Header().Set("Content-Type", "application/xml; charset=utf-8")
	w.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename="rsspipe-subscriptions.opml"`))
	w.WriteHeader(http.StatusOK)
	_, _ = w.Write(xmlData)
}