#include "csp/controllers/admin_controller.h"

#include "csp/app_state.h"
#include "csp/services/redeem_service.h"
#include "csp/services/user_service.h"
#include "http_auth.h"

#include <algorithm>
#include <cctype>
#include <exception>
#include <optional>
#include <stdexcept>
#include <string>

namespace csp::controllers {

namespace {

drogon::HttpResponsePtr JsonError(drogon::HttpStatusCode code,
                                  const std::string& msg) {
  Json::Value j;
  j["ok"] = false;
  j["error"] = msg;
  auto resp = drogon::HttpResponse::newHttpJsonResponse(j);
  resp->setStatusCode(code);
  return resp;
}

drogon::HttpResponsePtr JsonOk(const Json::Value& data) {
  Json::Value j;
  j["ok"] = true;
  j["data"] = data;
  auto resp = drogon::HttpResponse::newHttpJsonResponse(j);
  resp->setStatusCode(drogon::k200OK);
  return resp;
}

int ParseClampedInt(const std::string& s,
                    int default_value,
                    int min_value,
                    int max_value) {
  if (s.empty()) return default_value;
  const int v = std::stoi(s);
  return std::max(min_value, std::min(max_value, v));
}

bool ParseBoolLike(const std::string& raw, bool default_value) {
  if (raw.empty()) return default_value;
  std::string v = raw;
  std::transform(v.begin(), v.end(), v.begin(), [](unsigned char c) {
    return static_cast<char>(std::tolower(c));
  });
  if (v == "1" || v == "true" || v == "yes" || v == "on") return true;
  if (v == "0" || v == "false" || v == "no" || v == "off") return false;
  return default_value;
}

std::optional<int64_t> ParseOptionalInt64(const std::string& raw) {
  if (raw.empty()) return std::nullopt;
  return std::stoll(raw);
}

services::RedeemItemWrite ParseRedeemItemWrite(const Json::Value& json) {
  services::RedeemItemWrite write;
  write.name = json.get("name", "").asString();
  write.description = json.get("description", "").asString();
  write.unit_label = json.get("unit_label", "小时").asString();
  write.holiday_cost = json.get("holiday_cost", 5).asInt();
  write.studyday_cost = json.get("studyday_cost", 25).asInt();
  write.is_active = json.get("is_active", true).asBool();
  write.is_global = json.get("is_global", true).asBool();
  return write;
}

Json::Value ToJson(const services::RedeemItem& item) {
  Json::Value j;
  j["id"] = Json::Int64(item.id);
  j["name"] = item.name;
  j["description"] = item.description;
  j["unit_label"] = item.unit_label;
  j["holiday_cost"] = item.holiday_cost;
  j["studyday_cost"] = item.studyday_cost;
  j["is_active"] = item.is_active;
  j["is_global"] = item.is_global;
  j["created_by"] = Json::Int64(item.created_by);
  j["created_at"] = Json::Int64(item.created_at);
  j["updated_at"] = Json::Int64(item.updated_at);
  return j;
}

std::optional<int64_t> RequireAdminUserId(
    const drogon::HttpRequestPtr& req,
    std::function<void(const drogon::HttpResponsePtr&)>& cb) {
  std::string auth_error;
  const auto user_id = GetAuthedUserId(req, auth_error);
  if (!user_id.has_value()) {
    cb(JsonError(drogon::k401Unauthorized, auth_error));
    return std::nullopt;
  }

  services::UserService users(csp::AppState::Instance().db());
  const auto user = users.GetById(*user_id);
  if (!user.has_value() || user->username != "admin") {
    cb(JsonError(drogon::k403Forbidden, "admin only"));
    return std::nullopt;
  }
  return user_id;
}

}  // namespace

void AdminController::listUsers(
    const drogon::HttpRequestPtr& req,
    std::function<void(const drogon::HttpResponsePtr&)>&& cb) {
  try {
    if (!RequireAdminUserId(req, cb).has_value()) return;

    const int page = ParseClampedInt(req->getParameter("page"), 1, 1, 100000);
    const int page_size =
        ParseClampedInt(req->getParameter("page_size"), 50, 1, 200);

    services::UserService users(csp::AppState::Instance().db());
    const auto result = users.ListUsers(page, page_size);

    Json::Value arr(Json::arrayValue);
    for (const auto& item : result.items) {
      Json::Value one;
      one["id"] = Json::Int64(item.user_id);
      one["username"] = item.username;
      one["rating"] = item.rating;
      one["created_at"] = Json::Int64(item.created_at);
      arr.append(one);
    }

    Json::Value payload;
    payload["items"] = arr;
    payload["total_count"] = result.total_count;
    payload["page"] = page;
    payload["page_size"] = page_size;
    cb(JsonOk(payload));
  } catch (const std::invalid_argument&) {
    cb(JsonError(drogon::k400BadRequest, "invalid query parameter"));
  } catch (const std::out_of_range&) {
    cb(JsonError(drogon::k400BadRequest, "query parameter out of range"));
  } catch (const std::exception& e) {
    cb(JsonError(drogon::k500InternalServerError, e.what()));
  }
}

void AdminController::updateUserRating(
    const drogon::HttpRequestPtr& req,
    std::function<void(const drogon::HttpResponsePtr&)>&& cb,
    int64_t user_id) {
  try {
    if (!RequireAdminUserId(req, cb).has_value()) return;

    const auto json = req->getJsonObject();
    if (!json) {
      cb(JsonError(drogon::k400BadRequest, "body must be json"));
      return;
    }

    if (!(*json).isMember("rating")) {
      cb(JsonError(drogon::k400BadRequest, "rating is required"));
      return;
    }
    const int rating = (*json)["rating"].asInt();
    if (rating < 0) {
      cb(JsonError(drogon::k400BadRequest, "rating must be >= 0"));
      return;
    }

    services::UserService users(csp::AppState::Instance().db());
    users.SetRating(user_id, rating);

    const auto updated = users.GetById(user_id);
    if (!updated.has_value()) {
      cb(JsonError(drogon::k404NotFound, "user not found"));
      return;
    }

    Json::Value payload;
    payload["id"] = Json::Int64(updated->id);
    payload["username"] = updated->username;
    payload["rating"] = updated->rating;
    payload["updated"] = true;
    cb(JsonOk(payload));
  } catch (const std::invalid_argument&) {
    cb(JsonError(drogon::k400BadRequest, "invalid rating"));
  } catch (const std::exception& e) {
    cb(JsonError(drogon::k500InternalServerError, e.what()));
  }
}

void AdminController::deleteUser(
    const drogon::HttpRequestPtr& req,
    std::function<void(const drogon::HttpResponsePtr&)>&& cb,
    int64_t user_id) {
  try {
    const auto admin_user_id = RequireAdminUserId(req, cb);
    if (!admin_user_id.has_value()) return;

    if (*admin_user_id == user_id) {
      cb(JsonError(drogon::k400BadRequest, "cannot delete current admin user"));
      return;
    }

    services::UserService users(csp::AppState::Instance().db());
    const auto target = users.GetById(user_id);
    if (!target.has_value()) {
      cb(JsonError(drogon::k404NotFound, "user not found"));
      return;
    }
    if (target->username == "admin") {
      cb(JsonError(drogon::k400BadRequest, "cannot delete reserved admin user"));
      return;
    }

    users.DeleteUser(user_id);

    Json::Value payload;
    payload["id"] = Json::Int64(user_id);
    payload["username"] = target->username;
    payload["deleted"] = true;
    cb(JsonOk(payload));
  } catch (const std::exception& e) {
    cb(JsonError(drogon::k500InternalServerError, e.what()));
  }
}

void AdminController::listRedeemItems(
    const drogon::HttpRequestPtr& req,
    std::function<void(const drogon::HttpResponsePtr&)>&& cb) {
  try {
    if (!RequireAdminUserId(req, cb).has_value()) return;

    const bool include_inactive =
        ParseBoolLike(req->getParameter("include_inactive"), true);
    services::RedeemService redeem(csp::AppState::Instance().db());
    const auto items = redeem.ListItems(include_inactive);

    Json::Value arr(Json::arrayValue);
    for (const auto& item : items) arr.append(ToJson(item));
    cb(JsonOk(arr));
  } catch (const std::exception& e) {
    cb(JsonError(drogon::k500InternalServerError, e.what()));
  }
}

void AdminController::createRedeemItem(
    const drogon::HttpRequestPtr& req,
    std::function<void(const drogon::HttpResponsePtr&)>&& cb) {
  try {
    const auto admin_user_id = RequireAdminUserId(req, cb);
    if (!admin_user_id.has_value()) return;

    const auto json = req->getJsonObject();
    if (!json) {
      cb(JsonError(drogon::k400BadRequest, "body must be json"));
      return;
    }

    const auto input = ParseRedeemItemWrite(*json);
    services::RedeemService redeem(csp::AppState::Instance().db());
    const auto item = redeem.CreateItem(*admin_user_id, input);
    cb(JsonOk(ToJson(item)));
  } catch (const std::runtime_error& e) {
    cb(JsonError(drogon::k400BadRequest, e.what()));
  } catch (const std::exception& e) {
    cb(JsonError(drogon::k500InternalServerError, e.what()));
  }
}

void AdminController::updateRedeemItem(
    const drogon::HttpRequestPtr& req,
    std::function<void(const drogon::HttpResponsePtr&)>&& cb,
    int64_t item_id) {
  try {
    if (!RequireAdminUserId(req, cb).has_value()) return;

    const auto json = req->getJsonObject();
    if (!json) {
      cb(JsonError(drogon::k400BadRequest, "body must be json"));
      return;
    }

    const auto input = ParseRedeemItemWrite(*json);
    services::RedeemService redeem(csp::AppState::Instance().db());
    const auto item = redeem.UpdateItem(item_id, input);
    cb(JsonOk(ToJson(item)));
  } catch (const std::runtime_error& e) {
    cb(JsonError(drogon::k400BadRequest, e.what()));
  } catch (const std::exception& e) {
    cb(JsonError(drogon::k500InternalServerError, e.what()));
  }
}

void AdminController::deleteRedeemItem(
    const drogon::HttpRequestPtr& req,
    std::function<void(const drogon::HttpResponsePtr&)>&& cb,
    int64_t item_id) {
  try {
    if (!RequireAdminUserId(req, cb).has_value()) return;
    services::RedeemService redeem(csp::AppState::Instance().db());
    redeem.DeactivateItem(item_id);

    Json::Value payload;
    payload["id"] = Json::Int64(item_id);
    payload["deleted"] = true;
    cb(JsonOk(payload));
  } catch (const std::runtime_error& e) {
    cb(JsonError(drogon::k400BadRequest, e.what()));
  } catch (const std::exception& e) {
    cb(JsonError(drogon::k500InternalServerError, e.what()));
  }
}

void AdminController::listRedeemRecords(
    const drogon::HttpRequestPtr& req,
    std::function<void(const drogon::HttpResponsePtr&)>&& cb) {
  try {
    if (!RequireAdminUserId(req, cb).has_value()) return;

    const auto user_id = ParseOptionalInt64(req->getParameter("user_id"));
    const int limit = ParseClampedInt(req->getParameter("limit"), 200, 1, 500);

    services::RedeemService redeem(csp::AppState::Instance().db());
    const auto rows = redeem.ListRecordsAll(user_id, limit);

    Json::Value arr(Json::arrayValue);
    for (const auto& row : rows) {
      Json::Value j;
      j["id"] = Json::Int64(row.id);
      j["user_id"] = Json::Int64(row.user_id);
      j["username"] = row.username;
      j["item_id"] = Json::Int64(row.item_id);
      j["item_name"] = row.item_name;
      j["quantity"] = row.quantity;
      j["day_type"] = row.day_type;
      j["unit_cost"] = row.unit_cost;
      j["total_cost"] = row.total_cost;
      j["note"] = row.note;
      j["created_at"] = Json::Int64(row.created_at);
      arr.append(j);
    }
    cb(JsonOk(arr));
  } catch (const std::invalid_argument&) {
    cb(JsonError(drogon::k400BadRequest, "invalid query parameter"));
  } catch (const std::out_of_range&) {
    cb(JsonError(drogon::k400BadRequest, "query parameter out of range"));
  } catch (const std::exception& e) {
    cb(JsonError(drogon::k500InternalServerError, e.what()));
  }
}

}  // namespace csp::controllers