// src/api/client.js — API wrapper for MultiSense-DF backend

const API_BASE = import.meta.env.VITE_API_BASE || 'http://localhost:8000';

/**
 * Mock results for demo mode
 */
export const DEMO_RESULTS = {
  verdict: 'FAKE',
  confidence: 0.923,
  visual_score: 0.871,
  audio_score: 0.956,
  lipsync_score: 0.834,
  contributions: { visual: 0.38, audio: 0.41, lipsync: 0.21 },
  sync_profile: [
    0.82, 0.79, 0.81, 0.23, 0.19, 0.21, 0.18, 0.76, 0.78, 0.72,
    0.15, 0.14, 0.17, 0.13, 0.68, 0.71, 0.69, 0.22, 0.24, 0.19,
    0.81, 0.83, 0.79, 0.14, 0.12, 0.16, 0.71, 0.73, 0.68, 0.21,
    0.84, 0.82, 0.78, 0.17, 0.15, 0.19, 0.72, 0.74, 0.71, 0.23,
    0.83, 0.81, 0.76, 0.18, 0.14, 0.21, 0.69, 0.73, 0.70, 0.25,
  ],
  gradcam_image: null,
  filename: 'demo_video.mp4',
};

/**
 * Analyze a video file. Returns structured detection results.
 * Throws if the request fails.
 */
export async function analyzeVideo(file, onProgress) {
  const formData = new FormData();
  formData.append('file', file);

  // Simulate early-stage progress while uploading
  onProgress && onProgress('uploading');

  const response = await fetch(`${API_BASE}/analyze`, {
    method: 'POST',
    body: formData,
  });

  if (!response.ok) {
    const errorText = await response.text().catch(() => 'Unknown server error');
    throw new Error(`Server returned ${response.status}: ${errorText}`);
  }

  const data = await response.json();
  return data;
}

/**
 * Simulate analysis with demo data — fetches from /demo/fake if backend is up,
 * otherwise falls back to the local DEMO_RESULTS mock.
 */
export async function runDemoAnalysis(onStepChange) {
  const steps = [
    { key: 'frames',   delay: 900 },
    { key: 'audio',    delay: 900 },
    { key: 'lipsync',  delay: 900 },
    { key: 'fusion',   delay: 700 },
    { key: 'done',     delay: 300 },
  ];

  // Walk through visual progress steps
  for (let i = 0; i < steps.length - 1; i++) {
    onStepChange && onStepChange(steps[i].key);
    await sleep(steps[i].delay);
  }

  // Try to get real demo data from backend, fall back to local mock
  let result = DEMO_RESULTS;
  try {
    const res = await fetch(`${API_BASE}/demo/fake?filename=celeb_df_sample.mp4`);
    if (res.ok) result = await res.json();
  } catch (_) {
    // backend not reachable — use local mock
  }

  onStepChange && onStepChange('done');
  await sleep(300);
  return result;
}


function sleep(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}