import { getPreferenceValues } from "@vicinae/api";
import { DEFAULT_HOST, DEFAULT_MODEL } from "./constants";

/**
 * Preferences, read and normalised.
 *
 * Declared locally rather than relying on the `vicinae-env.d.ts` that the
 * `vici` toolchain generates, so this file typechecks and unit-tests without a
 * codegen step. The manifest in `package.json` remains the source of truth; if
 * a preference is added there, mirror it here.
 */

export interface LamPreferences {
  apiKey?: string;
  model?: string;
  ollamaHost?: string;
  systemPrompt?: string;
  webSearchEnabled?: boolean;
  thinking?: string;
  showToolCalls?: boolean;
  showReasoning?: boolean;
  resumeTimeout?: string;
}

/** Preferences with every optional value filled in, so callers never branch on undefined. */
export interface ResolvedPreferences {
  apiKey: string;
  model: string;
  host: string;
  systemPrompt: string;
  webEnabled: boolean;
  /** Undefined when reasoning is off, which is what the API client expects. */
  think?: string;
  /** Whether the transcript lists the tools Lam called. */
  showToolCalls: boolean;
  /** Whether the transcript includes the model's thinking trace. */
  showReasoning: boolean;
  /** Idle time after which opening the command starts a fresh chat. Undefined means never. */
  resumeTimeoutMs?: number;
}

const MINUTE = 60_000;
const HOUR = 60 * MINUTE;
const DAY = 24 * HOUR;

/** Keep in sync with the `resumeTimeout` dropdown in `package.json`. */
const RESUME_TIMEOUTS: Record<string, number> = {
  "15m": 15 * MINUTE,
  "1h": HOUR,
  "6h": 6 * HOUR,
  "1d": DAY,
};

/** `undefined` for "never" and for anything unrecognised, which both mean "always reopen the last chat". */
export function resolveResumeTimeout(value: string | undefined): number | undefined {
  return RESUME_TIMEOUTS[(value ?? "").trim()];
}

/** Human-readable form of {@link ResolvedPreferences.resumeTimeoutMs}, for the setup screen. */
export function describeResumeTimeout(milliseconds: number | undefined): string {
  if (milliseconds === undefined) return "Never — always reopen the last chat";

  const minutes = Math.round(milliseconds / MINUTE);
  if (minutes < 60) return `After ${minutes} minutes`;

  const hours = Math.round(minutes / 60);
  if (hours < 24) return `After ${hours} hour${hours === 1 ? "" : "s"}`;

  const days = Math.round(hours / 24);
  return `After ${days} day${days === 1 ? "" : "s"}`;
}

export function resolvePreferences(raw: LamPreferences): ResolvedPreferences {
  const thinking = (raw.thinking ?? "").trim();

  return {
    apiKey: (raw.apiKey ?? "").trim(),
    model: (raw.model ?? "").trim() || DEFAULT_MODEL,
    host: (raw.ollamaHost ?? "").trim() || DEFAULT_HOST,
    systemPrompt: (raw.systemPrompt ?? "").trim(),
    // Defaults to on: the preference is a checkbox the user has to actively untick.
    webEnabled: raw.webSearchEnabled ?? true,
    think: thinking && thinking !== "off" ? thinking : undefined,
    showToolCalls: raw.showToolCalls ?? true,
    showReasoning: raw.showReasoning ?? true,
    // Falls back to the manifest's declared default, so a missing preference
    // behaves the same whether Vicinae substitutes it or not.
    resumeTimeoutMs: resolveResumeTimeout(raw.resumeTimeout ?? "1h"),
  };
}

export function getLamPreferences(): ResolvedPreferences {
  return resolvePreferences(getPreferenceValues<LamPreferences>());
}

/** True when the extension cannot work until the user supplies a key. */
export function needsSetup(preferences: ResolvedPreferences): boolean {
  return preferences.apiKey.length === 0;
}