//  PipeScore - online bagpipe notation
//  Copyright (C) macarc
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <https://www.gnu.org/licenses/>.

import m from 'mithril';
import { IStave } from '.';
import { IBar } from '../Bar';
import { drawBar, minWidth, totalFixedWidth } from '../Bar/view';
import { Dispatch } from '../Dispatch';
import { GracenoteState } from '../Gracenote/state';
import { NoteState } from '../Note/state';
import { settings } from '../global/settings';
import { foreach, sum } from '../global/utils';

interface StaveProps {
  x: number;
  y: number;
  width: number;
  justAddedNote: boolean;
  previousStaveY: number;
  previousStave: IStave | null;
  noteState: NoteState;
  gracenoteState: GracenoteState;
  dispatch: Dispatch;
}

export const trebleClefWidth = 30;
export const stavelineThickness = 1;

export function minStaveGap() {
  return settings.lineHeightOf(2);
}

// The algorithm for computing bar widths is:
// - Ignoring anacruses, work out the average bar width
// - Each anacruses should be its .anacrusisWidth()
// - Each fixedWidth bar m (i.e. each bar where the barline has been dragged
//   by the user) should have width m.fixedWidth, and the next non-fixedWidth
//   bar should be longer by the difference between m.fixedWidth and the average
//   bar width
// The reason we can't ignore fixedWidth bars when computing average bar width
// is that when dragging the barline of a bar, the other barlines shouldn't move

// Returns a list where the pixel width at the nth index is that of the nth bar
function computeBarWidths(
  stave: IStave,
  staveWidth: number,
  previousBar: (i: number) => IBar | null
): number[] {
  const anacruses = stave.bars().filter((bar) => bar.isAnacrusis());
  const fixedWidth = sum(
    anacruses.map((bar, i) => totalFixedWidth(bar, previousBar(i)))
  );
  const widthAvailable = staveWidth - trebleClefWidth - fixedWidth;
  const averageBarWidth = widthAvailable / (stave.bars().length - anacruses.length);
  let extraWidth = 0;

  return stave.bars().map((bar, i) => {
    if (bar.isAnacrusis()) {
      return totalFixedWidth(bar, previousBar(i));
    }
    if (bar.fixedWidth !== 'auto') {
      extraWidth += bar.fixedWidth - averageBarWidth;
      return bar.fixedWidth;
    }
    const width = averageBarWidth - extraWidth;
    if (width <= 0) {
      console.error(`Bar has width ${width}!`);
    }
    extraWidth = 0;
    return width;
  });
}

function renderTrebleClef(x: number, y: number) {
  const scale = 0.00034 * settings.lineHeightOf(5);
  const baseline = 8149 * scale;
  // https://upload.wikimedia.org/wikipedia/commons/f/fa/Treble_clef.svg
  return m(
    'g',
    {
      transform: `translate(${x - 9} ${
        y - baseline + settings.lineHeightOf(3)
      }) scale(${scale})`,
    },
    m('path', {
      d: 'M 2002,7851 C 1941,7868 1886,7906 1835,7964 C 1784,8023 1759,8088 1759,8158 C 1759,8202 1774,8252 1803,8305 C 1832,8359 1876,8398 1933,8423 C 1952,8427 1961,8437 1961,8451 C 1961,8456 1954,8461 1937,8465 C 1846,8442 1771,8393 1713,8320 C 1655,8246 1625,8162 1623,8066 C 1626,7963 1657,7867 1716,7779 C 1776,7690 1853,7627 1947,7590 L 1878,7235 C 1724,7363 1599,7496 1502,7636 C 1405,7775 1355,7926 1351,8089 C 1353,8162 1368,8233 1396,8301 C 1424,8370 1466,8432 1522,8489 C 1635,8602 1782,8661 1961,8667 C 2022,8663 2087,8652 2157,8634 L 2002,7851 z M 2074,7841 L 2230,8610 C 2384,8548 2461,8413 2461,8207 C 2452,8138 2432,8076 2398,8021 C 2365,7965 2321,7921 2265,7889 C 2209,7857 2146,7841 2074,7841 z M 1869,6801 C 1902,6781 1940,6746 1981,6697 C 2022,6649 2062,6592 2100,6528 C 2139,6463 2170,6397 2193,6330 C 2216,6264 2227,6201 2227,6143 C 2227,6118 2225,6093 2220,6071 C 2216,6035 2205,6007 2186,5988 C 2167,5970 2143,5960 2113,5960 C 2053,5960 1999,5997 1951,6071 C 1914,6135 1883,6211 1861,6297 C 1838,6384 1825,6470 1823,6557 C 1828,6656 1844,6737 1869,6801 z M 1806,6859 C 1761,6697 1736,6532 1731,6364 C 1732,6256 1743,6155 1764,6061 C 1784,5967 1813,5886 1851,5816 C 1888,5746 1931,5693 1979,5657 C 2022,5625 2053,5608 2070,5608 C 2083,5608 2094,5613 2104,5622 C 2114,5631 2127,5646 2143,5666 C 2262,5835 2322,6039 2322,6277 C 2322,6390 2307,6500 2277,6610 C 2248,6719 2205,6823 2148,6920 C 2090,7018 2022,7103 1943,7176 L 2024,7570 C 2068,7565 2098,7561 2115,7561 C 2191,7561 2259,7577 2322,7609 C 2385,7641 2439,7684 2483,7739 C 2527,7793 2561,7855 2585,7925 C 2608,7995 2621,8068 2621,8144 C 2621,8262 2590,8370 2528,8467 C 2466,8564 2373,8635 2248,8681 C 2256,8730 2270,8801 2291,8892 C 2311,8984 2326,9057 2336,9111 C 2346,9165 2350,9217 2350,9268 C 2350,9347 2331,9417 2293,9479 C 2254,9541 2202,9589 2136,9623 C 2071,9657 1999,9674 1921,9674 C 1811,9674 1715,9643 1633,9582 C 1551,9520 1507,9437 1503,9331 C 1506,9284 1517,9240 1537,9198 C 1557,9156 1584,9122 1619,9096 C 1653,9069 1694,9055 1741,9052 C 1780,9052 1817,9063 1852,9084 C 1886,9106 1914,9135 1935,9172 C 1955,9209 1966,9250 1966,9294 C 1966,9353 1946,9403 1906,9444 C 1866,9485 1815,9506 1754,9506 L 1731,9506 C 1770,9566 1834,9597 1923,9597 C 1968,9597 2014,9587 2060,9569 C 2107,9550 2146,9525 2179,9493 C 2212,9461 2234,9427 2243,9391 C 2260,9350 2268,9293 2268,9222 C 2268,9174 2263,9126 2254,9078 C 2245,9031 2231,8968 2212,8890 C 2193,8813 2179,8753 2171,8712 C 2111,8727 2049,8735 1984,8735 C 1875,8735 1772,8713 1675,8668 C 1578,8623 1493,8561 1419,8481 C 1346,8401 1289,8311 1248,8209 C 1208,8108 1187,8002 1186,7892 C 1190,7790 1209,7692 1245,7600 C 1281,7507 1327,7419 1384,7337 C 1441,7255 1500,7180 1561,7113 C 1623,7047 1704,6962 1806,6859 z ',
      fill: '#131516',
      stroke: '#131516',
      'stroke-width': 3,
    })
  );
}

export function drawStave(stave: IStave, props: StaveProps): m.Children {
  const staveY = props.y + stave.gapAsNumber();

  const staveLines = foreach(5, (idx) => settings.lineHeightOf(idx) + staveY);

  const previousBar = (barIdx: number) =>
    barIdx === 0 ? props.previousStave?.lastBar() || null : stave.bars()[barIdx - 1];

  const widths = computeBarWidths(stave, props.width, previousBar);
  const width = (index: number) => widths[index];
  const getX = (barIdx: number) =>
    props.x +
    trebleClefWidth +
    sum(
      stave
        .bars()
        .slice(0, barIdx)
        .map((_, i) => width(i))
    );

  const barProps = (bar: IBar, index: number) => ({
    x: getX(index),
    y: staveY,
    width: width(index),
    previousBar: previousBar(index),
    justAddedNote: props.justAddedNote,
    shouldRenderLastBarline: stave.bars()[index + 1]
      ? stave.bars()[index + 1].timeSignature().equals(bar.timeSignature())
      : true,
    mustNotRenderFirstBarline: index === 0,
    endOfLastStave: props.x + props.width, // width should always be the same
    noteState: props.noteState,
    gracenoteState: props.gracenoteState,
    canResize: (newWidth: number) => {
      // If the new width is smaller than the minimum, can't resize
      // Only enforce if we aren't making the bar larger (in case everything's really cramped)
      if (newWidth < minWidth(bar, previousBar(index)) && newWidth < widths[index]) {
        return false;
      }

      const next = stave.bars()[index + 1];
      if (next) {
        const barRHS = getX(index) + newWidth;
        const furthestRightPossibleNextLHS =
          getX(index + 1) + width(index + 1) - minWidth(next, bar);

        // If the end of the bar would overlap with the next bar, can't resize
        if (barRHS > furthestRightPossibleNextLHS) {
          return false;
        }
        return true;
      }

      // If there's no next bar, we're at the end of the stave, so can't resize
      return false;
    },
    resize: (widthChange: number) => {
      // Subtract width change from the next bar, to make space for this bar
      const next = stave.bars()[index + 1];
      if (next?.fixedWidth !== 'auto') {
        next.fixedWidth -= widthChange;
      }
    },
    dispatch: props.dispatch,
  });

  return m('g[class=stave]', [
    renderTrebleClef(props.x, staveY),
    m(
      'g[class=bars]',
      stave.bars().map((bar, idx) => drawBar(bar, barProps(bar, idx)))
    ),
    m(
      'g[class=stave-lines]',
      staveLines.map((y) =>
        m('line', {
          x1: props.x,
          x2: props.x + props.width,
          y1: y,
          y2: y,
          stroke: 'black',
          'stroke-width': stavelineThickness,
          'pointer-events': 'none',
        })
      )
    ),
  ]);
}