import { homedir } from "node:os";
import type { ModuleContext, RenderedModule } from "../types";

function formatTokens(count: number): string {
  if (count < 1000) return count.toString();
  if (count < 10000) return `${(count / 1000).toFixed(1)}k`;
  if (count < 1000000) return `${Math.round(count / 1000)}k`;
  if (count < 10000000) return `${(count / 1000000).toFixed(1)}M`;
  return `${Math.round(count / 1000000)}M`;
}

function sessionEntries(ctx: any): any[] {
  try {
    return ctx.sessionManager?.getEntries?.() ?? [];
  } catch {
    return [];
  }
}

function totalCost(ctx: any): number {
  return sessionEntries(ctx).reduce((total, entry) => {
    const cost =
      entry?.type === "message" && entry.message?.role === "assistant"
        ? entry.message.usage?.cost?.total
        : undefined;
    return (
      total + (typeof cost === "number" && Number.isFinite(cost) ? cost : 0)
    );
  }, 0);
}

function isUsingSubscription(ctx: any): boolean {
  const provider = ctx.model?.provider;
  if (!provider) return false;
  try {
    return Boolean(ctx.modelRegistry?.isUsingOAuth?.(ctx.model));
  } catch {
    return provider === "anthropic" || provider === "openai-codex";
  }
}

export function directoryModule(moduleCtx: ModuleContext): RenderedModule {
  const cwd = moduleCtx.ctx.sessionManager?.getCwd?.() ?? process.cwd();
  const home = homedir();
  let text = home && cwd.startsWith(home) ? `~${cwd.slice(home.length)}` : cwd;

  // Git And Session Name
  const options = moduleCtx.config.modules.directory;
  if (options?.showGitBranch) {
    const branch = moduleCtx.footerData?.getGitBranch?.();
    if (branch) text = `${text} (${branch})`;
  }
  if (options?.showSessionName) {
    const sessionName = moduleCtx.ctx.sessionManager?.getSessionName?.();
    if (sessionName) text = `${text} • ${sessionName}`;
  }

  return { text };
}

export function contextModule(moduleCtx: ModuleContext): RenderedModule {
  const usage = moduleCtx.ctx.getContextUsage?.();
  const contextWindow =
    usage?.contextWindow ?? moduleCtx.ctx.model?.contextWindow ?? 0;
  const percent = usage?.percent;
  const showWindow = moduleCtx.config.modules.context?.showWindow ?? false;
  const value =
    percent === null || percent === undefined
      ? "?"
      : `${Number(percent).toFixed(1)}%`;
  return {
    text: showWindow ? `${value} / ${formatTokens(contextWindow)}` : `${value}`,
  };
}

export function modelModule(moduleCtx: ModuleContext): RenderedModule {
  const model = moduleCtx.ctx.model;
  if (!model) return { text: "no-model" };

  // Model Label
  const options = moduleCtx.config.modules.model;
  const provider = options?.showProvider ? `(${model.provider}) ` : "";
  let text = `${provider}${model.id}`;
  if (options?.showThinking && model.reasoning) {
    const thinking = moduleCtx.state.thinkingLevel ?? "off";
    text = thinking === "off" ? `${text} thinking off` : `${text} ${thinking}`;
  }
  return { text };
}

export function thinkingModule(moduleCtx: ModuleContext): RenderedModule {
  if (!moduleCtx.ctx.model?.reasoning) return { text: "" };
  const level = moduleCtx.state.thinkingLevel ?? "off";
  if (level === "off" && moduleCtx.config.modules.thinking?.hideWhenOff)
    return { text: "" };
  return { text: `think ${level}` };
}

export function costModule(moduleCtx: ModuleContext): RenderedModule {
  const cost = totalCost(moduleCtx.ctx);
  const subscription = isUsingSubscription(moduleCtx.ctx);
  if (!cost && !subscription) return { text: "" };
  if (subscription && moduleCtx.config.modules.cost?.showSubscription !== false)
    return { text: cost ? `$${cost.toFixed(3)} sub` : "sub" };
  return { text: `$${cost.toFixed(3)}` };
}