import type { AppSettings, ApiMode, SavedModelCredential } from "./types";

const SETTINGS_KEY = "task-polisher.settings.v3";
const LEGACY_SETTINGS_KEY = "task-polisher.settings.v2";

export const MODEL_OPTIONS = [
  "deepseek-v4-pro",
  "gpt-5.4",
  "gpt-5.3-codex",
  "gpt-5",
  "gpt-5-codex",
  "z-ai/glm-5.1",
  "custom",
];

export const DEFAULT_SETTINGS: AppSettings = {
  ruleProfile: "echo-05061347",
  polishTransport: "browser",
  analysisTransport: "backend",
  apiMode: "chat",
  baseURL: "https://api.deepseek.com",
  apiKey: "",
  savedModelCredentials: [],
  selectedModelCredentialId: "",
  modelPreset: "deepseek-v4-pro",
  customModel: "",
  concurrency: 3,
  temperature: 0.7,
  topP: 1,
  maxTokens: 32768,
  enableThinking: true,
  clearThinking: false,
};

export function resolveModel(settings: AppSettings): string {
  return settings.modelPreset === "custom" ? settings.customModel.trim() : settings.modelPreset;
}

export function defaultBaseURLForMode(_apiMode: ApiMode): string {
  return "https://api.deepseek.com";
}

export function applyDeepSeekPreset(settings: AppSettings): AppSettings {
  return sanitizeSettings({
    ...settings,
    apiMode: "chat",
    baseURL: "https://api.deepseek.com",
    selectedModelCredentialId: "",
    modelPreset: "deepseek-v4-pro",
    customModel: "",
    temperature: 0.7,
    topP: 1,
    maxTokens: 32768,
    enableThinking: true,
    clearThinking: false,
  });
}

export function loadSettings(): AppSettings {
  const stored = readJson(SETTINGS_KEY) ?? readJson(LEGACY_SETTINGS_KEY) ?? {};
  return sanitizeSettings({ ...DEFAULT_SETTINGS, ...stored });
}

export function saveSettings(settings: AppSettings): AppSettings {
  const sanitized = sanitizeSettings(settings);
  window.localStorage.setItem(SETTINGS_KEY, JSON.stringify(sanitized));
  return sanitized;
}

export function sanitizeSettings(raw: Partial<AppSettings>): AppSettings {
  const apiMode = raw.apiMode === "responses" ? "responses" : "chat";
  const modelPreset = MODEL_OPTIONS.includes(String(raw.modelPreset)) ? String(raw.modelPreset) : DEFAULT_SETTINGS.modelPreset;
  const customModel = modelPreset === "custom" ? String(raw.customModel || "").trim() : "";
  const baseURL = String(raw.baseURL || DEFAULT_SETTINGS.baseURL).trim() || defaultBaseURLForMode(apiMode);
  const apiKey = String(raw.apiKey || "").trim();
  const savedModelCredentials = sanitizeSavedModelCredentials(raw.savedModelCredentials);
  const selectedModelCredentialId = savedModelCredentials.some((item) => item.id === raw.selectedModelCredentialId)
    ? String(raw.selectedModelCredentialId)
    : "";

  return {
    ruleProfile: String(raw.ruleProfile || DEFAULT_SETTINGS.ruleProfile),
    polishTransport: "browser",
    analysisTransport: "backend",
    apiMode,
    baseURL,
    apiKey,
    savedModelCredentials,
    selectedModelCredentialId,
    modelPreset,
    customModel,
    concurrency: clampInteger(raw.concurrency, 1, 8, DEFAULT_SETTINGS.concurrency),
    temperature: clampNumber(raw.temperature, 0, 2, DEFAULT_SETTINGS.temperature),
    topP: clampNumber(raw.topP, 0, 1, DEFAULT_SETTINGS.topP),
    maxTokens: clampInteger(raw.maxTokens, 1, 131072, DEFAULT_SETTINGS.maxTokens),
    enableThinking: raw.enableThinking !== false,
    clearThinking: Boolean(raw.clearThinking),
  };
}

function sanitizeSavedModelCredentials(value: unknown): SavedModelCredential[] {
  if (!Array.isArray(value)) return [];
  const seen = new Set<string>();
  return value
    .map((item, index) => {
      const raw = item as Partial<SavedModelCredential>;
      const baseURL = String(raw?.baseURL || "").trim();
      const apiKey = String(raw?.apiKey || "").trim();
      if (!baseURL || !apiKey) return null;
      const id = String(raw?.id || "").trim() || makeCredentialId(baseURL, index);
      if (seen.has(id)) return null;
      seen.add(id);
      return {
        id,
        name: String(raw?.name || "").trim() || baseURL,
        baseURL,
        apiKey,
      };
    })
    .filter((item): item is SavedModelCredential => Boolean(item));
}

function makeCredentialId(baseURL: string, index: number): string {
  return `credential-${index}-${baseURL.toLowerCase().replace(/[^a-z0-9]+/g, "-").replace(/^-|-$/g, "").slice(0, 40) || "model"}`;
}

function clampNumber(value: unknown, min: number, max: number, fallback: number): number {
  const parsed = Number(value);
  if (!Number.isFinite(parsed)) return fallback;
  return Math.min(max, Math.max(min, parsed));
}

function clampInteger(value: unknown, min: number, max: number, fallback: number): number {
  return Math.round(clampNumber(value, min, max, fallback));
}

function readJson(key: string): Record<string, unknown> | null {
  try {
    const raw = window.localStorage.getItem(key);
    return raw ? JSON.parse(raw) : null;
  } catch {
    return null;
  }
}