import type { FirmInfo, Lawyer } from '../types/card';

const POSTER_WIDTH = 500;
const POSTER_HEIGHT = 400;
const EXPORT_SCALE = 2;
const EXPORT_WIDTH = POSTER_WIDTH * EXPORT_SCALE;
const EXPORT_HEIGHT = POSTER_HEIGHT * EXPORT_SCALE;
const BACKGROUND_COLOR = '#f4f0ee';
const PRIMARY_COLOR = '#8E2230';
const PRIMARY_DARK = '#5C0D15';
const TEXT_MAIN = '#1A1A1A';

type CanvasNode = WechatMiniprogram.Canvas;
type Canvas2DContext = any;
type CanvasImage = any;

export const SHARE_POSTER_CANVAS_ID = 'sharePosterCanvas';

export interface SharePosterPayload {
  canvas: CanvasNode;
  firm: Pick<FirmInfo, 'name' | 'logo' | 'hqAddress'>;
  lawyer: Pick<Lawyer, 'name' | 'title' | 'office' | 'phone' | 'email' | 'address' | 'avatar'>;
}

interface PosterAssets {
  avatarImage: CanvasImage | null;
  logoImage: CanvasImage | null;
}

interface ContactRow {
  kind: 'phone' | 'email' | 'address';
  value: string;
  maxLines: number;
}

interface MultilineTextOptions {
  x: number;
  y: number;
  maxWidth: number;
  lineHeight: number;
  maxLines: number;
  color: string;
  font: string;
}

function normalizeText(value: string | undefined | null): string {
  return typeof value === 'string' ? value.trim() : '';
}

function buildBrandInitial(name: string): string {
  const normalizedName = normalizeText(name);
  return normalizedName ? normalizedName.slice(0, 1) : '律';
}

function buildContactRows(payload: SharePosterPayload): ContactRow[] {
  const rows: ContactRow[] = [];
  const phone = normalizeText(payload.lawyer.phone);
  const email = normalizeText(payload.lawyer.email);
  const address = normalizeText(payload.lawyer.address) || normalizeText(payload.firm.hqAddress);

  if (phone) {
    rows.push({ kind: 'phone', value: phone, maxLines: 1 });
  }
  if (email) {
    rows.push({ kind: 'email', value: email, maxLines: 1 });
  }
  if (address) {
    rows.push({ kind: 'address', value: address, maxLines: 2 });
  }

  return rows;
}

function getImageInfo(src: string): Promise<string> {
  const normalizedSrc = normalizeText(src);
  if (!normalizedSrc) {
    return Promise.resolve('');
  }

  return new Promise((resolve) => {
    wx.getImageInfo({
      src: normalizedSrc,
      success: (result) => {
        resolve(result.path || normalizedSrc);
      },
      fail: () => {
        resolve('');
      },
    });
  });
}

function loadCanvasImage(canvas: CanvasNode, src: string): Promise<CanvasImage | null> {
  const normalizedSrc = normalizeText(src);
  if (!normalizedSrc) {
    return Promise.resolve(null);
  }

  return new Promise((resolve) => {
    const image = canvas.createImage();
    image.onload = () => resolve(image);
    image.onerror = () => resolve(null);
    image.src = normalizedSrc;
  });
}

async function preloadAssets(payload: SharePosterPayload): Promise<PosterAssets> {
  const [avatarPath, logoPath] = await Promise.all([
    getImageInfo(payload.lawyer.avatar),
    getImageInfo(payload.firm.logo),
  ]);
  const [avatarImage, logoImage] = await Promise.all([
    loadCanvasImage(payload.canvas, avatarPath),
    loadCanvasImage(payload.canvas, logoPath),
  ]);

  return {
    avatarImage,
    logoImage,
  };
}

function createRoundedRectPath(
  ctx: Canvas2DContext,
  x: number,
  y: number,
  width: number,
  height: number,
  radius: number
) {
  const safeRadius = Math.min(radius, width / 2, height / 2);
  ctx.beginPath();
  ctx.moveTo(x + safeRadius, y);
  ctx.lineTo(x + width - safeRadius, y);
  ctx.arcTo(x + width, y, x + width, y + safeRadius, safeRadius);
  ctx.lineTo(x + width, y + height - safeRadius);
  ctx.arcTo(x + width, y + height, x + width - safeRadius, y + height, safeRadius);
  ctx.lineTo(x + safeRadius, y + height);
  ctx.arcTo(x, y + height, x, y + height - safeRadius, safeRadius);
  ctx.lineTo(x, y + safeRadius);
  ctx.arcTo(x, y, x + safeRadius, y, safeRadius);
  ctx.closePath();
}

function fillRoundedRect(
  ctx: Canvas2DContext,
  x: number,
  y: number,
  width: number,
  height: number,
  radius: number,
  color: string
) {
  createRoundedRectPath(ctx, x, y, width, height, radius);
  ctx.fillStyle = color;
  ctx.fill();
}

function clipRoundedImage(
  ctx: Canvas2DContext,
  image: CanvasImage,
  x: number,
  y: number,
  width: number,
  height: number,
  radius: number
) {
  ctx.save();
  createRoundedRectPath(ctx, x, y, width, height, radius);
  ctx.clip();
  ctx.drawImage(image, x, y, width, height);
  ctx.restore();
}

function drawPhoneIcon(ctx: Canvas2DContext, x: number, y: number) {
  ctx.save();
  ctx.strokeStyle = PRIMARY_DARK;
  ctx.lineWidth = 1.8;
  ctx.lineCap = 'round';
  ctx.beginPath();
  ctx.moveTo(x + 5, y + 8);
  ctx.quadraticCurveTo(x + 4, y + 10, x + 6, y + 13);
  ctx.lineTo(x + 9, y + 16);
  ctx.quadraticCurveTo(x + 11, y + 18, x + 13, y + 17);
  ctx.lineTo(x + 15, y + 15);
  ctx.quadraticCurveTo(x + 16.5, y + 13.5, x + 15.5, y + 12);
  ctx.lineTo(x + 13.5, y + 10);
  ctx.quadraticCurveTo(x + 12, y + 8.5, x + 10.5, y + 9.5);
  ctx.lineTo(x + 9.5, y + 10.5);
  ctx.quadraticCurveTo(x + 8.5, y + 11.5, x + 7.5, y + 10.5);
  ctx.lineTo(x + 6.5, y + 9.5);
  ctx.quadraticCurveTo(x + 5.5, y + 8.5, x + 6.5, y + 7.5);
  ctx.lineTo(x + 7.5, y + 6.5);
  ctx.quadraticCurveTo(x + 8.5, y + 5, x + 7, y + 3.5);
  ctx.lineTo(x + 5, y + 1.5);
  ctx.quadraticCurveTo(x + 3.5, y, x + 2.5, y + 2);
  ctx.lineTo(x + 1.5, y + 4);
  ctx.quadraticCurveTo(x + 0.5, y + 6, x + 2.5, y + 7.5);
  ctx.stroke();
  ctx.restore();
}

function drawEmailIcon(ctx: Canvas2DContext, x: number, y: number) {
  ctx.save();
  ctx.strokeStyle = PRIMARY_DARK;
  ctx.lineWidth = 1.6;
  ctx.lineJoin = 'round';
  createRoundedRectPath(ctx, x + 1, y + 3, 18, 14, 4);
  ctx.stroke();
  ctx.beginPath();
  ctx.moveTo(x + 3.5, y + 5.5);
  ctx.lineTo(x + 10, y + 11);
  ctx.lineTo(x + 16.5, y + 5.5);
  ctx.stroke();
  ctx.restore();
}

function drawAddressIcon(ctx: Canvas2DContext, x: number, y: number) {
  ctx.save();
  ctx.strokeStyle = PRIMARY_DARK;
  ctx.lineWidth = 1.6;
  ctx.lineJoin = 'round';
  ctx.lineCap = 'round';
  ctx.beginPath();
  ctx.moveTo(x + 10, y + 18);
  ctx.bezierCurveTo(x + 15, y + 12.5, x + 17, y + 9.5, x + 17, y + 7);
  ctx.arc(x + 10, y + 7, 7, 0, Math.PI, true);
  ctx.bezierCurveTo(x + 3, y + 9.5, x + 5, y + 12.5, x + 10, y + 18);
  ctx.stroke();
  ctx.beginPath();
  ctx.arc(x + 10, y + 7, 2.3, 0, Math.PI * 2);
  ctx.stroke();
  ctx.restore();
}

function drawContactIcon(ctx: Canvas2DContext, kind: ContactRow['kind'], x: number, y: number) {
  fillRoundedRect(ctx, x, y, 28, 28, 14, 'rgba(142,34,48,0.07)');
  if (kind === 'phone') {
    drawPhoneIcon(ctx, x + 6, y + 5);
    return;
  }
  if (kind === 'email') {
    drawEmailIcon(ctx, x + 4, y + 4);
    return;
  }
  drawAddressIcon(ctx, x + 4, y + 4);
}

function buildWrappedLines(
  ctx: Canvas2DContext,
  text: string,
  maxWidth: number,
  maxLines: number
): { lines: string[]; truncated: boolean } {
  const normalizedText = normalizeText(text);
  if (!normalizedText) {
    return { lines: [], truncated: false };
  }

  const paragraphs = normalizedText.split(/\n+/).filter(Boolean);
  const lines: string[] = [];
  let truncated = false;

  for (let paragraphIndex = 0; paragraphIndex < paragraphs.length; paragraphIndex += 1) {
    const paragraph = paragraphs[paragraphIndex];
    let currentLine = '';

    for (let index = 0; index < paragraph.length; index += 1) {
      const nextLine = `${currentLine}${paragraph[index]}`;
      if (ctx.measureText(nextLine).width <= maxWidth) {
        currentLine = nextLine;
        continue;
      }

      if (currentLine) {
        lines.push(currentLine);
      }
      currentLine = paragraph[index];

      if (lines.length >= maxLines) {
        truncated = true;
        break;
      }
    }

    if (lines.length >= maxLines) {
      truncated = true;
      break;
    }

    if (currentLine) {
      lines.push(currentLine);
    }
  }

  const finalLines = lines.slice(0, maxLines);
  if (truncated && finalLines.length > 0) {
    let lastLine = finalLines[finalLines.length - 1];
    while (lastLine && ctx.measureText(`${lastLine}...`).width > maxWidth) {
      lastLine = lastLine.slice(0, -1);
    }
    finalLines[finalLines.length - 1] = `${lastLine}...`;
  }

  return { lines: finalLines, truncated };
}

function drawMultilineText(
  ctx: Canvas2DContext,
  text: string,
  options: MultilineTextOptions
): number {
  const normalizedText = normalizeText(text);
  if (!normalizedText) {
    return 0;
  }

  ctx.fillStyle = options.color;
  ctx.font = options.font;
  ctx.textAlign = 'left';
  ctx.textBaseline = 'top';
  const { lines: finalLines } = buildWrappedLines(ctx, normalizedText, options.maxWidth, options.maxLines);

  finalLines.forEach((line, index) => {
    ctx.fillText(line, options.x, options.y + index * options.lineHeight);
  });

  return finalLines.length * options.lineHeight;
}

function drawBackground(ctx: Canvas2DContext) {
  const gradient = ctx.createLinearGradient(0, 0, POSTER_WIDTH, POSTER_HEIGHT);
  gradient.addColorStop(0, '#fbf8f6');
  gradient.addColorStop(1, BACKGROUND_COLOR);

  ctx.fillStyle = gradient;
  ctx.fillRect(0, 0, POSTER_WIDTH, POSTER_HEIGHT);

  ctx.save();
  ctx.globalAlpha = 0.14;
  const ribbonGradient = ctx.createLinearGradient(80, 0, 360, 240);
  ribbonGradient.addColorStop(0, '#c9929b');
  ribbonGradient.addColorStop(1, '#8E2230');
  ctx.fillStyle = ribbonGradient;
  ctx.beginPath();
  ctx.moveTo(220, 0);
  ctx.lineTo(POSTER_WIDTH, 0);
  ctx.lineTo(POSTER_WIDTH, 180);
  ctx.lineTo(340, 280);
  ctx.closePath();
  ctx.fill();
  ctx.restore();

  ctx.save();
  ctx.globalAlpha = 0.08;
  ctx.fillStyle = PRIMARY_DARK;
  ctx.beginPath();
  ctx.moveTo(0, 220);
  ctx.lineTo(110, 150);
  ctx.lineTo(180, 190);
  ctx.lineTo(0, 340);
  ctx.closePath();
  ctx.fill();
  ctx.restore();
}

function drawHeaderSection(ctx: Canvas2DContext, payload: SharePosterPayload, assets: PosterAssets): number {
  const avatarX = 46;
  const avatarY = 62;
  const avatarSize = 108;

  if (assets.avatarImage) {
    clipRoundedImage(ctx, assets.avatarImage, avatarX, avatarY, avatarSize, avatarSize, 20);
  } else {
    fillRoundedRect(ctx, avatarX, avatarY, avatarSize, avatarSize, 20, 'rgba(142,34,48,0.12)');
    ctx.fillStyle = PRIMARY_COLOR;
    ctx.font = '600 28px sans-serif';
    ctx.textAlign = 'center';
    ctx.textBaseline = 'middle';
      ctx.fillText(buildBrandInitial(payload.lawyer.name), avatarX + avatarSize / 2, avatarY + avatarSize / 2);
  }

  const infoX = 176;
  ctx.textAlign = 'left';
  ctx.textBaseline = 'top';
  ctx.fillStyle = TEXT_MAIN;
  ctx.font = '600 35px sans-serif';
  ctx.fillText(payload.lawyer.name || '未命名律师', infoX, 80);

  ctx.fillStyle = PRIMARY_COLOR;
  ctx.font = '600 20px sans-serif';
  ctx.fillText(payload.lawyer.title || '律师', infoX, 128);

  return 226;
}

function drawContactRows(ctx: Canvas2DContext, rows: ContactRow[], startY: number): number {
  let currentY = startY;

  rows.forEach((row, index) => {
    ctx.save();
    if (index > 0) {
      ctx.strokeStyle = 'rgba(142,34,48,0.08)';
      ctx.lineWidth = 1;
      ctx.beginPath();
      ctx.moveTo(96, currentY - 12);
      ctx.lineTo(430, currentY - 12);
      ctx.stroke();
    }

    drawContactIcon(ctx, row.kind, 52, currentY - 3);

    const usedHeight = drawMultilineText(ctx, row.value, {
      x: 98,
      y: currentY - 1,
      maxWidth: 334,
      lineHeight: row.maxLines > 1 ? 24 : 22,
      maxLines: row.maxLines,
      color: TEXT_MAIN,
      font: row.maxLines > 1 ? '500 16px sans-serif' : '600 18px sans-serif',
    });

    currentY += Math.max(usedHeight, 30) + 18;
    ctx.restore();
  });

  return currentY;
}

function drawPoster(ctx: Canvas2DContext, payload: SharePosterPayload, assets: PosterAssets) {
  drawBackground(ctx);
  const contactRows = buildContactRows(payload);
  const contactStartY = 234;
  drawHeaderSection(ctx, payload, assets);
  drawContactRows(ctx, contactRows, contactStartY);
}

function configureCanvas(canvas: CanvasNode): Canvas2DContext {
  const context = canvas.getContext('2d') as Canvas2DContext;
  canvas.width = EXPORT_WIDTH;
  canvas.height = EXPORT_HEIGHT;
  if (typeof context.setTransform === 'function') {
    context.setTransform(1, 0, 0, 1, 0, 0);
  }
  context.clearRect(0, 0, EXPORT_WIDTH, EXPORT_HEIGHT);
  context.scale(EXPORT_SCALE, EXPORT_SCALE);
  return context;
}

function exportCanvas(canvas: CanvasNode): Promise<string> {
  return new Promise((resolve, reject) => {
    wx.canvasToTempFilePath({
      canvas,
      x: 0,
      y: 0,
      width: POSTER_WIDTH,
      height: POSTER_HEIGHT,
      destWidth: EXPORT_WIDTH,
      destHeight: EXPORT_HEIGHT,
      fileType: 'jpg',
      quality: 0.92,
      success: (result) => {
        resolve(result.tempFilePath);
      },
      fail: () => {
        reject(new Error('分享海报导出失败'));
      },
    });
  });
}

export async function generateSharePoster(payload: SharePosterPayload): Promise<string> {
  const ctx = configureCanvas(payload.canvas);
  const assets = await preloadAssets(payload);
  drawPoster(ctx, payload, assets);
  return exportCanvas(payload.canvas);
}