package moderation

import (
	"context"
	"database/sql"
	"encoding/json"
	"errors"
	"net/http"
	"time"

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

// Handler handles server moderation actions.
type Handler struct {
	db  *sql.DB
	hub *gateway.Hub
}

// NewHandler creates a new moderation handler.
func NewHandler(db *sql.DB, hub *gateway.Hub) *Handler {
	return &Handler{db: db, hub: hub}
}

type banRequest struct {
	UserID string `json:"user_id"`
	Reason string `json:"reason"`
}

type muteRequest struct {
	UserID   string `json:"user_id"`
	Reason   string `json:"reason"`
	Duration string `json:"duration"` // e.g. "15m", "1h", "1d", empty = permanent
}

// banResponse is the JSON shape returned when banning a user.
type banResponse struct {
	ID        string `json:"id"`
	ServerID  string `json:"server_id"`
	UserID    string `json:"user_id"`
	BannedBy  string `json:"banned_by"`
	Reason    string `json:"reason"`
	CreatedAt string `json:"created_at"`
}

// Ban bans a user from a server.
func (h *Handler) Ban(w http.ResponseWriter, r *http.Request) {
	serverID := chi.URLParam(r, "serverID")
	userID, ok := middleware.UserIDFromContext(r.Context())
	if !ok {
		http.Error(w, `{"error":"unauthorized"}`, http.StatusUnauthorized)
		return
	}

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

	// Remove member if present.
	_, _ = h.db.ExecContext(r.Context(), `DELETE FROM members WHERE server_id = $1 AND user_id = $2`, serverID, req.UserID)

	var ban banResponse
	err := h.db.QueryRowContext(r.Context(), `
		INSERT INTO bans (server_id, user_id, banned_by, reason)
		VALUES ($1, $2, $3, $4)
		RETURNING id, server_id, user_id, banned_by, reason, created_at::text
	`, serverID, req.UserID, userID, req.Reason).Scan(&ban.ID, &ban.ServerID, &ban.UserID, &ban.BannedBy, &ban.Reason, &ban.CreatedAt)
	if err != nil {
		http.Error(w, `{"error":"failed to ban user"}`, http.StatusInternalServerError)
		return
	}

	if h.hub != nil {
		h.hub.BroadcastToServer(serverID, gateway.Event{
			Type: gateway.EventMemberRemove,
			Data: map[string]string{"server_id": serverID, "user_id": req.UserID},
		})
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(ban)
}

// Unban removes a ban.
func (h *Handler) Unban(w http.ResponseWriter, r *http.Request) {
	serverID := chi.URLParam(r, "serverID")
	targetID := chi.URLParam(r, "userID")
	_, err := h.db.ExecContext(r.Context(), `DELETE FROM bans WHERE server_id = $1 AND user_id = $2`, serverID, targetID)
	if err != nil {
		http.Error(w, `{"error":"failed to unban user"}`, http.StatusInternalServerError)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// ListBans lists banned users.
func (h *Handler) ListBans(w http.ResponseWriter, r *http.Request) {
	serverID := chi.URLParam(r, "serverID")
	rows, err := h.db.QueryContext(r.Context(), `
		SELECT b.id, b.server_id, b.user_id, b.banned_by, b.reason, b.created_at::text, u.username
		FROM bans b
		JOIN users u ON u.id = b.user_id
		WHERE b.server_id = $1
		ORDER BY b.created_at DESC
	`, serverID)
	if err != nil {
		http.Error(w, `{"error":"server error"}`, http.StatusInternalServerError)
		return
	}
	defer rows.Close()

	type item struct {
		banResponse
		Username string `json:"username"`
	}
	var bans []item
	for rows.Next() {
		var b item
		if err := rows.Scan(&b.ID, &b.ServerID, &b.UserID, &b.BannedBy, &b.Reason, &b.CreatedAt, &b.Username); err != nil {
			continue
		}
		bans = append(bans, b)
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(bans)
}

// Kick removes a member from a server.
func (h *Handler) Kick(w http.ResponseWriter, r *http.Request) {
	serverID := chi.URLParam(r, "serverID")
	targetID := chi.URLParam(r, "userID")
	_, err := h.db.ExecContext(r.Context(), `DELETE FROM members WHERE server_id = $1 AND user_id = $2`, serverID, targetID)
	if err != nil {
		http.Error(w, `{"error":"failed to kick user"}`, http.StatusInternalServerError)
		return
	}
	if h.hub != nil {
		h.hub.BroadcastToServer(serverID, gateway.Event{
			Type: gateway.EventMemberRemove,
			Data: map[string]string{"server_id": serverID, "user_id": targetID},
		})
	}
	w.WriteHeader(http.StatusNoContent)
}

// Mute creates a server mute.
func (h *Handler) Mute(w http.ResponseWriter, r *http.Request) {
	serverID := chi.URLParam(r, "serverID")
	userID, ok := middleware.UserIDFromContext(r.Context())
	if !ok {
		http.Error(w, `{"error":"unauthorized"}`, http.StatusUnauthorized)
		return
	}
	var req muteRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil || req.UserID == "" {
		http.Error(w, `{"error":"invalid request"}`, http.StatusBadRequest)
		return
	}
	var expiresAt sql.NullTime
	if req.Duration != "" {
		d, err := time.ParseDuration(req.Duration)
		if err != nil {
			http.Error(w, `{"error":"invalid duration"}`, http.StatusBadRequest)
			return
		}
		expiresAt = sql.NullTime{Time: time.Now().Add(d), Valid: true}
	}

	_, err := h.db.ExecContext(r.Context(), `
		INSERT INTO server_mutes (server_id, user_id, muted_by, reason, expires_at)
		VALUES ($1, $2, $3, $4, $5)
		ON CONFLICT (server_id, user_id) DO UPDATE SET muted_by = EXCLUDED.muted_by, reason = EXCLUDED.reason, expires_at = EXCLUDED.expires_at, created_at = NOW()
	`, serverID, req.UserID, userID, req.Reason, expiresAt)
	if err != nil {
		http.Error(w, `{"error":"failed to mute user"}`, http.StatusInternalServerError)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// Unmute removes a server mute.
func (h *Handler) Unmute(w http.ResponseWriter, r *http.Request) {
	serverID := chi.URLParam(r, "serverID")
	targetID := chi.URLParam(r, "userID")
	_, err := h.db.ExecContext(r.Context(), `DELETE FROM server_mutes WHERE server_id = $1 AND user_id = $2`, serverID, targetID)
	if err != nil {
		http.Error(w, `{"error":"failed to unmute user"}`, http.StatusInternalServerError)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// IsMuted checks whether a user is currently muted in a server.
func IsMuted(ctx context.Context, db *sql.DB, serverID, userID string) (bool, error) {
	var exists bool
	err := db.QueryRowContext(ctx, `
		SELECT EXISTS(SELECT 1 FROM server_mutes WHERE server_id = $1 AND user_id = $2 AND (expires_at IS NULL OR expires_at > NOW()))
	`, serverID, userID).Scan(&exists)
	if errors.Is(err, sql.ErrNoRows) {
		return false, nil
	}
	return exists, err
}