// ─── CLI Renderer ───────────────────────────────────────────────────────────
// Beautiful terminal output: streaming, panels, events, spinners, markdown.

import type { HarnessEvent } from '../../core/events/index.js';

// ─── ANSI color helpers (no dependency needed for basic colors) ──────────────
const esc = (code: string) => `\x1b[${code}m`;
const reset = esc('0');
const bold = (s: string) => `${esc('1')}${s}${reset}`;
const dim = (s: string) => `${esc('2')}${s}${reset}`;
const green = (s: string) => `${esc('32')}${s}${reset}`;
const yellow = (s: string) => `${esc('33')}${s}${reset}`;
const blue = (s: string) => `${esc('34')}${s}${reset}`;
const magenta = (s: string) => `${esc('35')}${s}${reset}`;
const cyan = (s: string) => `${esc('36')}${s}${reset}`;
const red = (s: string) => `${esc('31')}${s}${reset}`;
const gray = (s: string) => `${esc('90')}${s}${reset}`;

// ─── Box Drawing ────────────────────────────────────────────────────────────
const BOX = { tl: '╭', tr: '╮', bl: '╰', br: '╯', h: '─', v: '│' };

function box(title: string, content: string, color: (s: string) => string = cyan, width = 72): string {
  const innerW = width - 4;
  const titleStr = ` ${title} `;
  const topLen = Math.max(0, innerW - titleStr.length);
  const top = color(`${BOX.tl}${BOX.h}${titleStr}${'─'.repeat(topLen)}${BOX.tr}`);
  const bot = color(`${BOX.bl}${'─'.repeat(innerW + 2)}${BOX.br}`);
  const lines = content.split('\n').map((l) => {
    const trimmed = l.slice(0, innerW);
    return `${color(BOX.v)} ${trimmed}${' '.repeat(Math.max(0, innerW - stripAnsi(trimmed).length))} ${color(BOX.v)}`;
  });
  return [top, ...lines, bot].join('\n');
}

function stripAnsi(s: string): string {
  return s.replace(/\x1b\[[0-9;]*m/g, '');
}

// ─── Spinner ────────────────────────────────────────────────────────────────
const SPINNER_FRAMES = ['⠋', '⠙', '⠹', '⠸', '⠼', '⠴', '⠦', '⠧', '⠇', '⠏'];

export class Spinner {
  private frame = 0;
  private interval: ReturnType<typeof setInterval> | null = null;
  private message = '';

  start(message: string): void {
    this.message = message;
    this.interval = setInterval(() => {
      this.frame = (this.frame + 1) % SPINNER_FRAMES.length;
      process.stdout.write(`\r${cyan(SPINNER_FRAMES[this.frame]!)} ${this.message}`);
    }, 80);
  }

  update(message: string): void {
    this.message = message;
  }

  stop(finalMessage?: string): void {
    if (this.interval) clearInterval(this.interval);
    this.interval = null;
    process.stdout.write(`\r${' '.repeat(this.message.length + 4)}\r`);
    if (finalMessage) console.log(finalMessage);
  }
}

// ─── Event Renderer ─────────────────────────────────────────────────────────
export interface RendererOptions {
  verbose: boolean;
  compact: boolean;
}

export class EventRenderer {
  private opts: RendererOptions;
  private spinner = new Spinner();
  private streamBuffer = '';

  constructor(opts: Partial<RendererOptions> = {}) {
    this.opts = { verbose: false, compact: false, ...opts };
  }

  render(event: HarnessEvent): void {
    switch (event.type) {
      case 'session.started':
        console.log('\n' + box('Session', `${bold('Goal:')} ${event.goal}\n${gray(`ID: ${event.sessionId}`)}`, cyan));
        break;

      case 'session.completed':
        this.flushStream();
        console.log('\n' + green(`✓ ${bold('Session completed')} — ${event.summary}`));
        break;

      case 'session.failed':
        this.flushStream();
        console.log('\n' + red(`✗ ${bold('Session failed')} — ${event.error}`));
        break;

      case 'plan.updated':
        if (!this.opts.compact) {
          const planStr = event.items.map((item) => {
            const icon = item.status === 'completed' ? green('✓') : item.status === 'in_progress' ? yellow('▶') : item.status === 'failed' ? red('✗') : gray('○');
            return `  ${icon} ${item.title}`;
          }).join('\n');
          console.log('\n' + box('Plan', planStr, magenta));
        }
        break;

      case 'model.request.start':
        this.spinner.start(`${event.provider}/${event.model} thinking…`);
        break;

      case 'model.request.end':
        this.spinner.stop();
        if (this.opts.verbose) {
          console.log(gray(`  ⏱ ${event.durationMs}ms | ${event.usage.totalTokens} tokens | ~$${(event.usage.estimatedCostUsd ?? 0).toFixed(4)}`));
        }
        break;

      case 'model.stream.delta':
        this.streamBuffer += event.text;
        process.stdout.write(event.text);
        break;

      case 'model.stream.end':
        this.flushStream();
        break;

      case 'tool.requested':
        console.log(`\n${blue('⚡')} ${bold(event.toolCall.toolName)} ${gray(`[${event.toolCall.id.slice(0, 8)}]`)}`);
        if (this.opts.verbose) {
          console.log(gray(`  Input: ${JSON.stringify(event.toolCall.input).slice(0, 200)}`));
        }
        break;

      case 'tool.started':
        this.spinner.start('Tool executing…');
        break;

      case 'tool.progress':
        this.spinner.update(event.message);
        break;

      case 'tool.finished':
        this.spinner.stop(green(`  ✓ Done`) + (this.opts.verbose ? gray(` (${event.durationMs}ms)`) : ''));
        break;

      case 'tool.failed':
        this.spinner.stop(red(`  ✗ Failed: ${event.error}`));
        break;

      case 'tool.denied':
        console.log(yellow(`  ⚠ Denied: ${event.reason}`));
        break;

      case 'evaluation.completed':
        const r = event.report;
        const icon = r.passed ? green('✓') : red('✗');
        const checksStr = r.checks.map((c) => `  ${c.passed ? green('✓') : red('✗')} ${c.name}${c.message ? gray(` — ${c.message}`) : ''}`).join('\n');
        console.log('\n' + box('Evaluation', `${icon} ${r.summary}\n${checksStr}`, r.passed ? green : red));
        break;

      case 'artifact.created':
        console.log(`${magenta('📎')} Artifact: ${bold(event.artifact.title)} ${gray(`(${event.artifact.type})`)}`);
        break;

      case 'budget.warning':
        console.log(yellow(`⚠ Budget warning: ${event.usage.totalTokens} tokens used`));
        break;

      case 'error':
        console.log(red(`✗ Error: ${event.message}`));
        break;
    }
  }

  private flushStream(): void {
    if (this.streamBuffer) {
      // Ensure newline after streamed content
      if (!this.streamBuffer.endsWith('\n')) process.stdout.write('\n');
      this.streamBuffer = '';
    }
  }
}

// ─── Header / Banner ────────────────────────────────────────────────────────
export function renderBanner(): void {
  console.log(`
${cyan(bold('╭─────────────────────────────────────╮'))}
${cyan(bold('│'))}  ${bold('⚡ AI Harness')}  ${gray('v0.1.0')}              ${cyan(bold('│'))}
${cyan(bold('│'))}  ${dim('model-agnostic CLI agent runtime')}  ${cyan(bold('│'))}
${cyan(bold('╰─────────────────────────────────────╯'))}
`);
}

// ─── Metrics Summary ────────────────────────────────────────────────────────
export function renderMetrics(metrics: {
  modelCalls: number; toolCalls: number; totalTokens: number;
  estimatedCostUsd: number; totalDurationMs: number; toolSuccessRate: number;
}): void {
  const content = [
    `${bold('Model calls:')}    ${metrics.modelCalls}`,
    `${bold('Tool calls:')}     ${metrics.toolCalls} (${Math.round(metrics.toolSuccessRate * 100)}% success)`,
    `${bold('Total tokens:')}   ${metrics.totalTokens.toLocaleString()}`,
    `${bold('Est. cost:')}      $${metrics.estimatedCostUsd.toFixed(4)}`,
    `${bold('Duration:')}       ${(metrics.totalDurationMs / 1000).toFixed(1)}s`,
  ].join('\n');
  console.log('\n' + box('Metrics', content, gray));
}