import os
import shutil
import subprocess
import tempfile
import atexit
import json
import threading
from modules.chart_engine.utils.file_utils import create_temp_file, cleanup_temp_file


_PERSISTENT_RENDERER = None
_PERSISTENT_RENDERER_LOCK = threading.Lock()


def _puppeteer_env():
    env = os.environ.copy()
    if env.get("PUPPETEER_EXECUTABLE_PATH"):
        return env
    for chrome_bin in (
        shutil.which("google-chrome"),
        shutil.which("chromium"),
        shutil.which("chromium-browser"),
        "/usr/bin/google-chrome",
        "/usr/bin/chromium",
        "/usr/bin/chromium-browser",
    ):
        if chrome_bin and os.path.exists(chrome_bin):
            env["PUPPETEER_EXECUTABLE_PATH"] = chrome_bin
            break
    return env


class _PersistentHtmlToSvgRenderer:
    def __init__(self):
        script_path = os.path.join(
            os.path.dirname(__file__),
            "persistent_html_to_svg_renderer.cjs",
        )
        self.proc = subprocess.Popen(
            ["node", script_path],
            stdin=subprocess.PIPE,
            stdout=subprocess.PIPE,
            stderr=subprocess.DEVNULL,
            text=True,
            bufsize=1,
            env=_puppeteer_env(),
        )
        self._next_id = 0
        self._write_lock = threading.Lock()
        self._pending_lock = threading.Lock()
        self._pending = {}
        self._reader = threading.Thread(target=self._read_loop, daemon=True)
        self._reader.start()

    def _read_loop(self):
        for line in self.proc.stdout:
            if not line.strip():
                continue
            response = json.loads(line)
            request_id = response["id"]
            with self._pending_lock:
                item = self._pending.get(request_id)
            if item is not None:
                item["response"] = response
                item["event"].set()

    def render(self, html_file, output_svg, width, height):
        event = threading.Event()
        with self._write_lock:
            self._next_id += 1
            request_id = self._next_id
            with self._pending_lock:
                self._pending[request_id] = {"event": event, "response": None}
            request = {
                "id": request_id,
                "htmlFile": os.path.abspath(html_file),
                "outputSvg": os.path.abspath(output_svg),
                "width": int(width),
                "height": int(height),
            }
            self.proc.stdin.write(json.dumps(request) + "\n")
            self.proc.stdin.flush()

        if not event.wait(60):
            with self._pending_lock:
                self._pending.pop(request_id, None)
            print(f"Error: puppeteer render timed out after 60s for {os.path.basename(html_file)}")
            return None

        with self._pending_lock:
            item = self._pending.pop(request_id)
        response = item["response"]
        if response.get("ok"):
            return output_svg
        print(
            f"Error: persistent puppeteer render failed for "
            f"{os.path.basename(html_file)}: {response.get('error')}"
        )
        return None

    def close(self):
        if self.proc.poll() is None:
            self.proc.terminate()


def _get_persistent_renderer():
    global _PERSISTENT_RENDERER
    with _PERSISTENT_RENDERER_LOCK:
        if _PERSISTENT_RENDERER is None or _PERSISTENT_RENDERER.proc.poll() is not None:
            _PERSISTENT_RENDERER = _PersistentHtmlToSvgRenderer()
        return _PERSISTENT_RENDERER


def _close_persistent_renderer():
    if _PERSISTENT_RENDERER is not None:
        _PERSISTENT_RENDERER.close()


atexit.register(_close_persistent_renderer)


def html_to_svg(html_file, output_svg=None, width=1200, height=800):
    """
    Convert an HTML file with ECharts or D3.js to SVG using Puppeteer.
    This requires a Node.js script to perform the conversion.
    
    Args:
        html_file: Path to the HTML file
        output_svg: Path to save the SVG file (optional)
        width: Width of the SVG
        height: Height of the SVG
    
    Returns:
        Path to the generated SVG file
    """
    if output_svg is None:
        output_svg = os.path.splitext(html_file)[0] + '.svg'

    if os.environ.get("CHARTPIPELINE_PERSISTENT_PUPPETEER", "1") != "0":
        return _get_persistent_renderer().render(html_file, output_svg, width, height)
    
    # Create a temporary Node.js script for the conversion using CommonJS syntax
    js_script = """
    const puppeteer = require('puppeteer');
    const fs = require('fs');
    const path = require('path');

    (async () => {
        const launchOpts = {
            headless: 'new',  // Use the new headless mode
            args: ['--no-sandbox', '--disable-setuid-sandbox']
        };
        if (process.env.PUPPETEER_EXECUTABLE_PATH) {
            launchOpts.executablePath = process.env.PUPPETEER_EXECUTABLE_PATH;
        }
        const browser = await puppeteer.launch(launchOpts);
        const page = await browser.newPage();
        await page.setViewport({ width: %d, height: %d });
        
        try {
            // Load the HTML file
            await page.goto('file://' + path.resolve('%s'), { waitUntil: 'networkidle0' });
            
            const svgReady = () => page.evaluate(() => {
                const hasReadySvg = (svg) => {
                    if (!svg || svg.childNodes.length === 0) {
                        return false;
                    }
                    return svg.querySelectorAll('path, circle, rect, g, text').length > 0;
                };

                const chartSvg = document.querySelector('#chart-container svg');
                if (hasReadySvg(chartSvg)) {
                    return true;
                }

                for (const selector of ['#svg-output', '#manual-svg-output']) {
                    const output = document.querySelector(selector);
                    if (output && output.innerHTML.trim() && output.querySelector('svg')) {
                        return true;
                    }
                }

                return false;
            });

            const waitStart = Date.now();
            while (Date.now() - waitStart < 3000 && !(await svgReady())) {
                await new Promise(resolve => setTimeout(resolve, 100));
            }
            
            // Check if it's an ECharts or D3.js chart
            const isECharts = await page.evaluate(() => {
                return typeof echarts !== 'undefined';
            });
            
            let svgContent;
            
            if (isECharts) {
                // For ECharts, we'll check if the SVG has already been rendered to #svg-output
                const hasSvgOutput = await page.evaluate(() => {
                    return document.querySelector('#svg-output') !== null;
                });
                
                if (hasSvgOutput) {
                    // If we have the SVG output div, use its content
                    svgContent = await page.evaluate(() => {
                        const svgOutput = document.querySelector('#svg-output');
                        return svgOutput.innerHTML;
                    });
                    
                    console.log('Successfully retrieved SVG from #svg-output');
                } else {
                    // If there's no SVG output yet, try alternative method
                    console.log('No #svg-output found, using alternative method');
                    
                    // Add a button to trigger SVG export for ECharts
                    await page.evaluate(() => {
                        // Add a button to the page to trigger SVG export
                        const button = document.createElement('button');
                        button.id = 'export-svg-button';
                        button.style.display = 'none';
                        button.onclick = function() {
                            const chart = echarts.getInstanceByDom(document.querySelector('#chart-container'));
                            if (chart) {
                                // Force animation off
                                chart.setOption({animation: false});
                                
                                // Try to explicitly render as SVG
                                try {
                                    chart.setOption({
                                        renderer: 'svg'
                                    });
                                } catch (e) {
                                    console.error('Failed to set SVG renderer:', e);
                                }
                                
                                // Try to get SVG string and save it
                                try {
                                    const svgContent = chart.renderToSVGString();
                                    if (svgContent) {
                                        const svgOutput = document.createElement('div');
                                        svgOutput.id = 'manual-svg-output';
                                        svgOutput.style.display = 'none';
                                        svgOutput.innerHTML = svgContent;
                                        document.body.appendChild(svgOutput);
                                    }
                                } catch (e) {
                                    console.error('Failed to get SVG string:', e);
                                }
                            }
                        };
                        document.body.appendChild(button);
                        
                        // Click the button to trigger SVG export
                        document.getElementById('export-svg-button').click();
                    });
                    
                    // Wait for the manual SVG to be rendered
                    await new Promise(resolve => setTimeout(resolve, 500));
                    
                    // Try to get the manual SVG content
                    const hasManualSvg = await page.evaluate(() => {
                        return document.querySelector('#manual-svg-output') !== null;
                    });
                    
                    if (hasManualSvg) {
                        svgContent = await page.evaluate(() => {
                            return document.querySelector('#manual-svg-output').innerHTML;
                        });
                        console.log('Successfully retrieved SVG from #manual-svg-output');
                    }
                }
            }
            
            // If we haven't got the SVG content yet, try to get it from the DOM
            if (!svgContent) {
                console.log('Attempting to extract SVG directly from DOM');
                svgContent = await page.evaluate(() => {
                    const container = document.querySelector('#chart-container');
                    if (!container) {
                        console.error('Chart container not found');
                        return null;
                    }
                    
                    const hasRenderableSvg = (svg) => (
                        svg && svg.childNodes.length > 0 &&
                        svg.querySelectorAll('path, circle, rect, g, text, line, polygon, polyline, ellipse, image').length > 0
                    );
                    const svgElement = Array.from(container.querySelectorAll('svg')).find(hasRenderableSvg);
                    if (!svgElement) {
                        console.error('SVG element not found in container');
                        return null;
                    }
                    
                    // 检查SVG内是否有内容
                    if (svgElement.childNodes.length === 0) {
                        console.error('SVG element is empty');
                        return null;
                    }
                    
                    // 检查是否有path或g元素
                    const hasGraphicElements = svgElement.querySelectorAll('path, circle, rect, g, text').length > 0;
                    if (!hasGraphicElements) {
                        console.error('SVG has no graphic elements');
                        // 但如果强制需要，我们仍然返回它
                    }
                    
                    // 查看ECharts图表的情况
                    if (typeof echarts !== 'undefined') {
                        const chart = echarts.getInstanceByDom(container);
                        if (chart) {
                            // 再次强制关闭动画
                            chart.setOption({animation: false});
                            
                            // 等待一小段时间
                            setTimeout(() => {
                                // 再次触发重绘
                                chart.resize();
                            }, 100);
                        }
                    }
                    
                    // Clone the SVG to avoid modifying the original
                    const svgClone = svgElement.cloneNode(true);
                    
                    // Add width and height attributes if they don't exist
                    if (!svgClone.hasAttribute('width')) {
                        svgClone.setAttribute('width', container.clientWidth);
                    }
                    if (!svgClone.hasAttribute('height')) {
                        svgClone.setAttribute('height', container.clientHeight);
                    }
                    
                    // Add viewBox if it doesn't exist
                    if (!svgClone.hasAttribute('viewBox')) {
                        svgClone.setAttribute('viewBox', `0 0 ${container.clientWidth} ${container.clientHeight}`);
                    }
                    
                    // 输出SVG中元素的数量用于调试
                    console.log(`SVG contains ${svgClone.querySelectorAll('*').length} elements`);
                    console.log(`SVG contains ${svgClone.querySelectorAll('path').length} paths`);
                    console.log(`SVG contains ${svgClone.querySelectorAll('g').length} groups`);
                    console.log(`SVG contains ${svgClone.querySelectorAll('text').length} text elements`);
                    
                    // Return the SVG as a string
                    return svgClone.outerHTML;
                });
            }
            
            if (!svgContent) {
                // 尝试最后的方法 - 直接从页面截图
                console.log('Failed to extract SVG content, attempting screenshot as fallback');
                
                // 截图前等待额外时间确保绘制完成
                await new Promise(resolve => setTimeout(resolve, 500));
                
                // 1. 获取页面截图
                // 为了避免格式化问题，使用硬编码的文件名
                const outputPath = '${OUTPUT_SVG_PATH}';
                const pngPath = outputPath.replace('.svg', '.png');
                await page.screenshot({path: pngPath, fullPage: true});
                console.log('Created PNG screenshot as fallback: ' + pngPath);
                
                // 2. 创建一个简单的SVG，引用PNG
                const pngFileName = path.basename(pngPath);
                const viewWidth = ${WIDTH};
                const viewHeight = ${HEIGHT};
                
                svgContent = `<svg width="${viewWidth}" height="${viewHeight}" xmlns="http://www.w3.org/2000/svg">
                    <title>Chart (Fallback)</title>
                    <desc>This is a fallback SVG using a PNG screenshot.</desc>
                    <image href="${pngFileName}" width="${viewWidth}" height="${viewHeight}" />
                </svg>`;
                
                console.error('Generated fallback SVG with embedded PNG reference');
            }
            
            // Write SVG to file
            fs.writeFileSync('%s', svgContent);
        } catch (error) {
            console.error('Error generating SVG:', error);
            process.exit(1);
        } finally {
            await browser.close();
        }
    })();
    """
    
    # 替换JavaScript模板中的特殊占位符
    js_script = js_script.replace('${OUTPUT_SVG_PATH}', output_svg.replace('\\', '\\\\'))
    js_script = js_script.replace('${WIDTH}', str(width))
    js_script = js_script.replace('${HEIGHT}', str(height))
    
    # 应用Python格式化参数
    js_script = js_script % (
        width,                          # SVG viewport width
        height,                         # SVG viewport height
        html_file.replace('\\', '\\\\'),# HTML file path
        output_svg.replace('\\', '\\\\') # Final SVG output path
    )
    
    # Create a temporary script file with random name in tmp directory
    js_file = create_temp_file(prefix="html_to_svg_", suffix=".cjs", content=js_script)
    
    # Run the Node.js script. Capture stdout/stderr so puppeteer's
    # ``console.log`` chatter ("Attempting to extract SVG directly from DOM",
    # etc.) doesn't pollute the parent process' fd=1 (which would bypass
    # any Python-level sys.stdout redirection done by the caller).
    #
    # We do still capture stdout (instead of DEVNULL) so that when the chart
    # falls through to the PNG fallback path we can surface what puppeteer
    # was complaining about. On the success path nothing is printed.
    def _decode(buf):
        if buf is None:
            return ""
        if isinstance(buf, (bytes, bytearray)):
            return buf.decode("utf-8", errors="replace")
        return str(buf)

    def _is_fallback_output(svg_path: str) -> bool:
        try:
            with open(svg_path, "r", encoding="utf-8", errors="ignore") as fh:
                head = fh.read(4096)
            return "This is a fallback SVG using a PNG screenshot" in head
        except OSError:
            return False

    try:
        completed = subprocess.run(
            ['node', js_file],
            check=True,
            timeout=60,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            env=_puppeteer_env(),
        )
        if _is_fallback_output(output_svg):
            out = _decode(completed.stdout).strip()
            err = _decode(completed.stderr).strip()
            print(
                "Error: puppeteer fell back to PNG screenshot for "
                f"{os.path.basename(html_file)}; node stderr=<<<\n{err}\n>>> "
                f"stdout-tail=<<<\n{out[-1500:]}\n>>>"
            )
        cleanup_temp_file(js_file)
        return output_svg
    except subprocess.TimeoutExpired as e:
        print(
            f"Error: puppeteer render timed out after 60s for "
            f"{os.path.basename(html_file)}"
        )
        cleanup_temp_file(js_file)
        return None
    except subprocess.CalledProcessError as e:
        err = _decode(e.stderr)
        out = _decode(e.stdout)
        print(
            f"Error: puppeteer render failed (rc={e.returncode}) for "
            f"{os.path.basename(html_file)}: stderr=<<<\n{err}\n>>> "
            f"stdout-tail=<<<\n{out[-1500:]}\n>>>"
        )
        cleanup_temp_file(js_file)
        return None