package channel

import (
	"context"
	"encoding/json"
	"net/http"
	"time"

	"git.dustin.coffee/hobokenchicken/dumpsterChat/internal/middleware"
	"github.com/go-chi/chi/v5"
)

type document struct {
	ID        string `json:"id"`
	ChannelID string `json:"channel_id"`
	CreatorID string `json:"creator_id"`
	Title     string `json:"title"`
	Content   string `json:"content"`
	CreatedAt string `json:"created_at"`
	UpdatedAt string `json:"updated_at"`
}

type createDocRequest struct {
	Title   string `json:"title"`
	Content string `json:"content"`
}

// ponytail: no version history, no lock/unlock. Add when concurrent editing arises.

func (h *Handler) registerDocRoutes(r chi.Router) {
	r.Get("/{channelID}/docs", h.ListDocs)
	r.Post("/{channelID}/docs", h.CreateDoc)
	r.Get("/docs/{docID}", h.GetDoc)
	r.Patch("/docs/{docID}", h.UpdateDoc)
	r.Delete("/docs/{docID}", h.DeleteDoc)
}

func (h *Handler) ListDocs(w http.ResponseWriter, r *http.Request) {
	channelID := chi.URLParam(r, "channelID")
	userID, _ := middleware.UserIDFromContext(r.Context())
	allowed := h.checkAccess(r.Context(), w, channelID, userID)
	if !allowed {
		return
	}

	rows, err := h.db.QueryContext(r.Context(), `
		SELECT id, channel_id, creator_id, title, created_at, updated_at
		FROM documents WHERE channel_id = $1
		ORDER BY updated_at DESC
	`, channelID)
	if err != nil {
		http.Error(w, `{"error":"server error"}`, http.StatusInternalServerError)
		return
	}
	defer rows.Close()

	// ponytail: list returns title-only summary, not full content
	type docSummary struct {
		ID        string `json:"id"`
		ChannelID string `json:"channel_id"`
		CreatorID string `json:"creator_id"`
		Title     string `json:"title"`
		CreatedAt string `json:"created_at"`
		UpdatedAt string `json:"updated_at"`
	}
	docs := make([]docSummary, 0)
	for rows.Next() {
		var d docSummary
		if err := rows.Scan(&d.ID, &d.ChannelID, &d.CreatorID, &d.Title, &d.CreatedAt, &d.UpdatedAt); err != nil {
			continue
		}
		docs = append(docs, d)
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(docs)
}

func (h *Handler) CreateDoc(w http.ResponseWriter, r *http.Request) {
	channelID := chi.URLParam(r, "channelID")
	userID, _ := middleware.UserIDFromContext(r.Context())
	allowed := h.checkAccess(r.Context(), w, channelID, userID)
	if !allowed {
		return
	}

	var req createDocRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil || req.Title == "" {
		http.Error(w, `{"error":"title required"}`, http.StatusBadRequest)
		return
	}

	var d document
	err := h.db.QueryRowContext(r.Context(), `
		INSERT INTO documents (channel_id, creator_id, title, content)
		VALUES ($1, $2, $3, $4)
		RETURNING id, channel_id, creator_id, title, content, created_at, updated_at
	`, channelID, userID, req.Title, req.Content).Scan(
		&d.ID, &d.ChannelID, &d.CreatorID, &d.Title, &d.Content, &d.CreatedAt, &d.UpdatedAt,
	)
	if err != nil {
		http.Error(w, `{"error":"failed to create doc"}`, http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(d)
}

func (h *Handler) GetDoc(w http.ResponseWriter, r *http.Request) {
	docID := chi.URLParam(r, "docID")
	// ponytail: check channel access via doc lookup
	var channelID, creatorID, title, content, createdAt, updatedAt string
	err := h.db.QueryRowContext(r.Context(), `
		SELECT id, channel_id, creator_id, title, content, created_at, updated_at
		FROM documents WHERE id = $1
	`, docID).Scan(&docID, &channelID, &creatorID, &title, &content, &createdAt, &updatedAt)
	if err != nil {
		http.Error(w, `{"error":"doc not found"}`, http.StatusNotFound)
		return
	}
	userID, _ := middleware.UserIDFromContext(r.Context())
	allowed := h.checkAccess(r.Context(), w, channelID, userID)
	if !allowed {
		return
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(document{
		ID: docID, ChannelID: channelID, CreatorID: creatorID,
		Title: title, Content: content, CreatedAt: createdAt, UpdatedAt: updatedAt,
	})
}

func (h *Handler) UpdateDoc(w http.ResponseWriter, r *http.Request) {
	docID := chi.URLParam(r, "docID")
	userID, _ := middleware.UserIDFromContext(r.Context())

	// get channel_id first for access check
	var channelID, creatorID string
	err := h.db.QueryRowContext(r.Context(), `SELECT channel_id, creator_id FROM documents WHERE id = $1`, docID).Scan(&channelID, &creatorID)
	if err != nil {
		http.Error(w, `{"error":"doc not found"}`, http.StatusNotFound)
		return
	}
	allowed := h.checkAccess(r.Context(), w, channelID, userID)
	if !allowed {
		return
	}

	var req createDocRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, `{"error":"invalid request"}`, http.StatusBadRequest)
		return
	}

	var d document
	err = h.db.QueryRowContext(r.Context(), `
		UPDATE documents SET title = COALESCE(NULLIF($2, ''), title), content = $3, updated_at = $4
		WHERE id = $1
		RETURNING id, channel_id, creator_id, title, content, created_at, updated_at
	`, docID, req.Title, req.Content, time.Now().UTC().Format(time.RFC3339)).Scan(
		&d.ID, &d.ChannelID, &d.CreatorID, &d.Title, &d.Content, &d.CreatedAt, &d.UpdatedAt,
	)
	if err != nil {
		http.Error(w, `{"error":"failed to update doc"}`, http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(d)
}

func (h *Handler) DeleteDoc(w http.ResponseWriter, r *http.Request) {
	docID := chi.URLParam(r, "docID")
	userID, _ := middleware.UserIDFromContext(r.Context())

	var channelID, creatorID string
	err := h.db.QueryRowContext(r.Context(), `SELECT channel_id, creator_id FROM documents WHERE id = $1`, docID).Scan(&channelID, &creatorID)
	if err != nil {
		http.Error(w, `{"error":"doc not found"}`, http.StatusNotFound)
		return
	}
	allowed := h.checkAccess(r.Context(), w, channelID, userID)
	if !allowed {
		return
	}

	_, err = h.db.ExecContext(r.Context(), `DELETE FROM documents WHERE id = $1`, docID)
	if err != nil {
		http.Error(w, `{"error":"failed to delete doc"}`, http.StatusInternalServerError)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// ponytail: shared access check, reuses isMember. No permission fine-tuning.
func (h *Handler) checkAccess(ctx context.Context, w http.ResponseWriter, channelID, userID string) bool {
	serverID, err := h.serverIDForChannel(ctx, channelID)
	if err != nil {
		http.Error(w, `{"error":"channel not found"}`, http.StatusNotFound)
		return false
	}
	ok, _ := h.isMember(ctx, userID, serverID)
	if !ok {
		http.Error(w, `{"error":"forbidden"}`, http.StatusForbidden)
		return false
	}
	return true
}