package api

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

	"github.com/jackc/pgx/v5"

	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
)

// sessionCookieMaxAge is the cookie lifetime. Sessions don't auto-expire
// server-side yet (future work); the cookie still caps browser-side lifetime
// so an abandoned laptop doesn't stay logged in forever.
const sessionCookieMaxAge = 30 * 24 * time.Hour

func (h *handlers) handleLogin(w http.ResponseWriter, r *http.Request) {
	var req LoginRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeErr(w, http.StatusBadRequest, "bad_request", "invalid JSON body")
		return
	}
	if req.Username == "" || req.Password == "" {
		writeErr(w, http.StatusBadRequest, "bad_request", "username and password required")
		return
	}

	q := dbq.New(h.pool)
	user, err := q.GetUserByUsername(r.Context(), req.Username)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			writeErr(w, http.StatusUnauthorized, "invalid_credentials", "invalid username or password")
			return
		}
		h.logger.Error("api: user lookup failed", "err", err)
		writeErr(w, http.StatusInternalServerError, "server_error", "lookup failed")
		return
	}
	if !auth.VerifyPassword(user.PasswordHash, req.Password) {
		writeErr(w, http.StatusUnauthorized, "invalid_credentials", "invalid username or password")
		return
	}

	token, err := auth.MintSessionToken()
	if err != nil {
		h.logger.Error("api: mint session token failed", "err", err)
		writeErr(w, http.StatusInternalServerError, "server_error", "mint failed")
		return
	}
	if _, err := q.InsertSession(r.Context(), dbq.InsertSessionParams{
		UserID:    user.ID,
		TokenHash: auth.HashSessionToken(token),
		UserAgent: r.UserAgent(),
	}); err != nil {
		h.logger.Error("api: insert session failed", "err", err)
		writeErr(w, http.StatusInternalServerError, "server_error", "insert failed")
		return
	}

	http.SetCookie(w, &http.Cookie{
		Name:     auth.SessionCookieName,
		Value:    token,
		Path:     "/",
		HttpOnly: true,
		Secure:   r.TLS != nil, // dev over http stays functional; prod over https gets Secure
		SameSite: http.SameSiteStrictMode,
		MaxAge:   int(sessionCookieMaxAge.Seconds()),
	})

	w.Header().Set("Content-Type", "application/json")
	_ = json.NewEncoder(w).Encode(LoginResponse{
		Token: token,
		User: UserView{
			ID:       user.ID,
			Username: user.Username,
			IsAdmin:  user.IsAdmin,
		},
	})
}