/**
 * Phase 1: Extract hex submaps from a source image for Claude-vision classification.
 *
 * Usage:
 *   npx tsx pipeline/extract-submaps.ts <image> <map-id> [options]
 *
 * Options:
 *   --region <q0,r0,q1,r1>   Only process hexes within this axial bounding box
 *
 * Output:
 *   submaps/<map-id>/manifest.json   Map config + processing order
 *   submaps/<map-id>/<q>_<r>.png     Annotated submap per hex (center in red)
 *
 * The manifest lists hexes in processing order (q asc, r asc) so Claude can
 * use left/top neighbours as context when classifying each hex.
 */

import sharp from 'sharp';
import { mkdirSync, writeFileSync, existsSync } from 'fs';
import { join, resolve, dirname } from 'path';
import { fileURLToPath } from 'url';
import { initDb, getDb } from '../server/db.js';
import { axialToPixel, hexVertices } from '../core/coords.js';
import { gridBoundsForImage } from '../core/hex-grid.js';
import { HexEdge, EDGE_DIRECTIONS, ALL_EDGES, type AxialCoord, type PixelCoord } from '../core/types.js';

const ROOT = resolve(dirname(fileURLToPath(import.meta.url)), '..');

// ─── Constants ────────────────────────────────────────────────────────────────

const PIXELS_PER_MEILE = 8;
const CROP_RADIUS_FACTOR = 2.8;

// ─── DB helpers ──────────────────────────────────────────────────────────────

interface MapConfig {
  id: number;
  image_width: number;
  image_height: number;
  hex_size: number;
  origin_x: number;
  origin_y: number;
}

function loadMapConfig(mapId: number): MapConfig {
  const db = getDb();
  const rows = db.exec(
    'SELECT id, image_width, image_height, hex_size, origin_x, origin_y FROM hex_maps WHERE id = ?',
    [mapId],
  );
  if (rows.length === 0 || rows[0].values.length === 0) {
    throw new Error(`Map ${mapId} not found in DB`);
  }
  const [id, image_width, image_height, hex_size, origin_x, origin_y] = rows[0].values[0] as number[];
  return { id, image_width, image_height, hex_size, origin_x, origin_y };
}

// ─── Submap extraction ────────────────────────────────────────────────────────

function buildHexSvg(
  center: AxialCoord,
  hexSize: number,
  origin: PixelCoord,
  cropLeft: number,
  cropTop: number,
  cropW: number,
  cropH: number,
): string {
  const EDGE_NAME: Record<HexEdge, string> = {
    [HexEdge.NE]: 'NE', [HexEdge.E]: 'E', [HexEdge.SE]: 'SE',
    [HexEdge.SW]: 'SW', [HexEdge.W]: 'W', [HexEdge.NW]: 'NW',
  };

  const hexCoords: Array<{ coord: AxialCoord; label?: string }> = [
    { coord: center },
    ...ALL_EDGES.map(e => {
      const d = EDGE_DIRECTIONS[e];
      return { coord: { q: center.q + d.q, r: center.r + d.r }, label: EDGE_NAME[e] };
    }),
  ];

  const polys = hexCoords.map(({ coord, label }, i) => {
    const px = axialToPixel(coord, hexSize, origin);
    const verts = hexVertices(px.x - cropLeft, px.y - cropTop, hexSize);
    const pts = verts.map(v => `${v.x.toFixed(1)},${v.y.toFixed(1)}`).join(' ');
    const isCenter = i === 0;

    const poly = `<polygon points="${pts}" fill="${isCenter ? 'rgba(255,60,60,0.10)' : 'none'}" `
      + `stroke="${isCenter ? '#ff3c3c' : '#ffffff'}" `
      + `stroke-width="${isCenter ? 2.5 : 1.2}" stroke-opacity="${isCenter ? 1 : 0.6}"/>`;

    if (!label) return poly;

    // Small direction label
    const lx = (px.x - cropLeft).toFixed(1);
    const ly = (px.y - cropTop).toFixed(1);
    const text = `<text x="${lx}" y="${ly}" text-anchor="middle" dominant-baseline="middle" `
      + `font-family="monospace" font-size="${Math.max(8, hexSize * 0.35)}" fill="white" opacity="0.7">${label}</text>`;
    return poly + text;
  });

  return `<svg width="${cropW}" height="${cropH}" xmlns="http://www.w3.org/2000/svg">\n`
    + polys.join('\n') + '\n</svg>';
}

async function extractSubmap(
  imagePath: string,
  coord: AxialCoord,
  hexSize: number,
  origin: PixelCoord,
  imageWidth: number,
  imageHeight: number,
  outputPath: string,
): Promise<void> {
  const px = axialToPixel(coord, hexSize, origin);
  const r  = Math.ceil(hexSize * CROP_RADIUS_FACTOR);

  const left   = Math.max(0, Math.round(px.x - r));
  const top    = Math.max(0, Math.round(px.y - r));
  const right  = Math.min(imageWidth,  Math.round(px.x + r));
  const bottom = Math.min(imageHeight, Math.round(px.y + r));
  const w = right - left;
  const h = bottom - top;

  const svg = buildHexSvg(coord, hexSize, origin, left, top, w, h);

  await sharp(imagePath)
    .extract({ left, top, width: w, height: h })
    .composite([{ input: Buffer.from(svg), top: 0, left: 0 }])
    .png({ compressionLevel: 6 })
    .toFile(outputPath);
}

// ─── Processing order ─────────────────────────────────────────────────────────

function sortCoords(coords: AxialCoord[]): AxialCoord[] {
  return [...coords].sort((a, b) => a.q !== b.q ? a.q - b.q : a.r - b.r);
}

// ─── Main ─────────────────────────────────────────────────────────────────────

async function main() {
  const args = process.argv.slice(2);
  const imagePath = args[0];
  const mapId     = parseInt(args[1], 10);

  if (!imagePath || isNaN(mapId)) {
    console.error('Usage: npx tsx pipeline/extract-submaps.ts <image> <map-id> [--region q0,r0,q1,r1]');
    process.exit(1);
  }

  let regionFilter: { q0: number; r0: number; q1: number; r1: number } | null = null;
  const regionIdx = args.indexOf('--region');
  if (regionIdx !== -1) {
    const [q0, r0, q1, r1] = args[regionIdx + 1].split(',').map(Number);
    regionFilter = { q0, r0, q1, r1 };
    console.log(`Region filter: q=[${q0},${q1}] r=[${r0},${r1}]`);
  }

  if (!existsSync(imagePath)) {
    console.error(`Image not found: ${imagePath}`);
    process.exit(1);
  }

  await initDb();
  const cfg = loadMapConfig(mapId);
  const { image_width, image_height, hex_size, origin_x, origin_y } = cfg;
  const origin: PixelCoord = { x: origin_x, y: origin_y };

  const hexesPerMeile = (hex_size * 2) / PIXELS_PER_MEILE;
  console.log(`Map ${mapId}: ${image_width}×${image_height}px, hexSize=${hex_size}px = ${hexesPerMeile} Meilen/Hex`);

  let { coords } = gridBoundsForImage(image_width, image_height, hex_size, origin);

  if (regionFilter) {
    const { q0, r0, q1, r1 } = regionFilter;
    coords = coords.filter(c => c.q >= q0 && c.q <= q1 && c.r >= r0 && c.r <= r1);
  }

  const sorted = sortCoords(coords);
  console.log(`Total hexes to extract: ${sorted.length}`);

  const outDir = join(ROOT, 'pipeline', 'submaps', String(mapId));
  mkdirSync(outDir, { recursive: true });

  // Write manifest
  const manifest = {
    mapId,
    imageWidth: image_width,
    imageHeight: image_height,
    hexSize: hex_size,
    originX: origin_x,
    originY: origin_y,
    meilenPerHex: hexesPerMeile,
    hexes: sorted.map(c => ({ q: c.q, r: c.r })),
  };
  writeFileSync(join(outDir, 'manifest.json'), JSON.stringify(manifest, null, 2));
  console.log(`Manifest written: ${sorted.length} hexes`);

  let done = 0;
  for (const coord of sorted) {
    const filename = `${coord.q}_${coord.r}.png`;
    const outPath  = join(outDir, filename);

    // Skip if already extracted (resumable)
    if (existsSync(outPath)) {
      done++;
      continue;
    }

    await extractSubmap(imagePath, coord, hex_size, origin, image_width, image_height, outPath);
    done++;

    if (done % 100 === 0 || done === sorted.length) {
      process.stdout.write(`  ${done}/${sorted.length}\r`);
    }
  }

  console.log(`\nExtracted ${done} submaps → ${outDir}`);
  console.log(`\nNext step: Claude classifies submaps in this session.`);
  console.log(`Then run: npx tsx pipeline/import-from-json.ts ${outDir}/classifications.json ${mapId}`);
}

main().catch(err => { console.error('Fatal:', err); process.exit(1); });