package api

import (
	"database/sql"
	"net/http"
	"strconv"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/yeniklas/terdut-server/internal/models"
)

func handleListComments(db *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		alertID, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
		if err != nil {
			respond(w, http.StatusBadRequest, errResp("invalid alert id"))
			return
		}

		// Verify the alert exists.
		var exists int
		if err := db.QueryRowContext(r.Context(), "SELECT 1 FROM alerts WHERE id = ?", alertID).Scan(&exists); err != nil {
			respond(w, http.StatusNotFound, errResp("alert not found"))
			return
		}

		rows, err := db.QueryContext(r.Context(), `
			SELECT c.id, c.alert_id, c.user_id, u.username, c.content, c.created_at
			FROM   alert_comments c
			JOIN   users u ON u.id = c.user_id
			WHERE  c.alert_id = ?
			ORDER  BY c.created_at ASC`, alertID)
		if err != nil {
			respond(w, http.StatusInternalServerError, errResp("internal error"))
			return
		}
		defer rows.Close()

		comments := []models.Comment{}
		for rows.Next() {
			var c models.Comment
			var ts int64
			if err := rows.Scan(&c.ID, &c.AlertID, &c.UserID, &c.Username, &c.Content, &ts); err != nil {
				respond(w, http.StatusInternalServerError, errResp("internal error"))
				return
			}
			c.CreatedAt = time.Unix(ts, 0).UTC()
			comments = append(comments, c)
		}
		respond(w, http.StatusOK, comments)
	}
}

func handleCreateComment(db *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		alertID, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
		if err != nil {
			respond(w, http.StatusBadRequest, errResp("invalid alert id"))
			return
		}

		var req struct {
			Content string `json:"content"`
		}
		if err := decodeJSON(r, &req); err != nil {
			respond(w, http.StatusBadRequest, errResp("invalid request body"))
			return
		}
		if req.Content == "" {
			respond(w, http.StatusBadRequest, errResp("content is required"))
			return
		}

		// Verify the alert exists.
		var exists int
		if err := db.QueryRowContext(r.Context(), "SELECT 1 FROM alerts WHERE id = ?", alertID).Scan(&exists); err != nil {
			respond(w, http.StatusNotFound, errResp("alert not found"))
			return
		}

		user, _ := userFromContext(r.Context())
		res, err := db.ExecContext(r.Context(),
			"INSERT INTO alert_comments (alert_id, user_id, content) VALUES (?, ?, ?)",
			alertID, user.ID, req.Content)
		if err != nil {
			respond(w, http.StatusInternalServerError, errResp("internal error"))
			return
		}
		commentID, _ := res.LastInsertId()

		comment := models.Comment{
			ID:        commentID,
			AlertID:   alertID,
			UserID:    user.ID,
			Username:  user.Username,
			Content:   req.Content,
			CreatedAt: time.Now().UTC(),
		}
		respond(w, http.StatusCreated, comment)
	}
}

func handleDeleteComment(db *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		alertID, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
		if err != nil {
			respond(w, http.StatusBadRequest, errResp("invalid alert id"))
			return
		}
		commentID, err := strconv.ParseInt(chi.URLParam(r, "commentID"), 10, 64)
		if err != nil {
			respond(w, http.StatusBadRequest, errResp("invalid comment id"))
			return
		}

		user, _ := userFromContext(r.Context())
		res, err := db.ExecContext(r.Context(),
			"DELETE FROM alert_comments WHERE id = ? AND alert_id = ? AND user_id = ?",
			commentID, alertID, user.ID)
		if err != nil {
			respond(w, http.StatusInternalServerError, errResp("internal error"))
			return
		}
		if n, _ := res.RowsAffected(); n == 0 {
			respond(w, http.StatusNotFound, errResp("comment not found"))
			return
		}
		w.WriteHeader(http.StatusNoContent)
	}
}