// ============================================================
//  QianfanOcrClient:百度千帆 PaddleOCR-VL-0.9B(版面解析)
//  · POST https://qianfan.baidubce.com/v2/ocr/paddleocr
//    Authorization: Bearer {QianfanApiKey}(千帆 ModelBuilder 的 API Key,永久有效)
//    {"model":"paddleocr-vl-0.9b","file":"<纯base64>","fileType":1}
//  · 响应 result.layoutParsingResults[0].prunedResult.parsing_res_list[]
//    每块 {block_label, block_content, block_bbox[x1,y1,x2,y2](像素)}
//    → 文本块转 OcrItem;表格块逐行拆(与 GLM 处理一致)
//  · Key 存 baidu_ocr.json 的 qianfan_api_key(OCR设置窗口写)
// ============================================================
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using System.Web.Script.Serialization;

namespace 成套报价软件
{
    /// <summary>百度千帆 PaddleOCR-VL 客户端(单实例)。</summary>
    internal sealed class QianfanOcrClient
    {
        private readonly JavaScriptSerializer _json = new JavaScriptSerializer();
        private string _apiKey;
        private const string BaseUrl = "https://qianfan.baidubce.com/v2/ocr/paddleocr";

        /// <summary>状态提示,接 OcrClient.StatusChanged。</summary>
        public event Action<string> StatusChanged;

        public QianfanOcrClient()
        {
            try
            {
                ServicePointManager.SecurityProtocol =
                    ServicePointManager.SecurityProtocol | SecurityProtocolType.Tls12;
            }
            catch { }
        }

        public bool IsConfigured
        {
            get { return !string.IsNullOrWhiteSpace(_apiKey); }
        }

        /// <summary>Key 由 OcrClient 从 baidu_ocr.json 的 qianfan_api_key 注入(热更新)。</summary>
        public void SetApiKey(string key)
        {
            _apiKey = key == null ? "" : key.Trim();
        }

        /// <summary>识别一块位图 → 文本块列表(带 bbox 像素坐标)。</summary>
        public Task<List<OcrItem>> RecognizeAsync(Bitmap crop, int timeoutMs)
        {
            if (crop == null || crop.Width <= 0 || crop.Height <= 0)
                return Task.FromResult(new List<OcrItem>());

            if (!IsConfigured)
            {
                Notify("千帆 PaddleOCR-VL 未配置 API Key(OCR 设置窗口里填千帆 API Key)");
                var tcs0 = new TaskCompletionSource<List<OcrItem>>();
                tcs0.SetException(new Exception(
                    "千帆 PaddleOCR-VL 未配置 API Key。\r\n" +
                    "请到百度智能云千帆平台(ModelBuilder)创建 API Key," +
                    "在 OCR 设置窗口选择引擎\"百度 PaddleOCR-VL\"并填入后保存。"));
                return tcs0.Task;
            }

            return Task.Factory.StartNew(() =>
            {
                var sw = System.Diagnostics.Stopwatch.StartNew();
                var result = RequestAndParse(crop, timeoutMs);
                Notify("PaddleOCR-VL·" + result.Count + "条 " + sw.ElapsedMilliseconds + "ms");
                return result;
            });
        }

        private List<OcrItem> RequestAndParse(Bitmap crop, int timeoutMs)
        {
            byte[] png;
            using (var ms = new MemoryStream())
            {
                crop.Save(ms, ImageFormat.Png);
                png = ms.ToArray();
            }
            // 千帆要求:base64 直传(无 data URI 前缀),fileType=1 图像
            string body = _json.Serialize(new Dictionary<string, object>
            {
                { "model", "paddleocr-vl-0.9b" },
                { "file", Convert.ToBase64String(png) },
                { "fileType", 1 }
            });

            var req = (HttpWebRequest)WebRequest.Create(BaseUrl);
            req.Method = "POST";
            req.ContentType = "application/json";
            req.Headers.Add("Authorization", "Bearer " + _apiKey);
            req.Timeout = timeoutMs;
            req.ReadWriteTimeout = timeoutMs;
            req.Proxy = null;
            var bytes = Encoding.UTF8.GetBytes(body);
            req.ContentLength = bytes.Length;
            using (var rs = req.GetRequestStream())
            {
                rs.Write(bytes, 0, bytes.Length);
            }

            string respText;
            try
            {
                using (var resp = (HttpWebResponse)req.GetResponse())
                using (var sr = new StreamReader(resp.GetResponseStream(), new UTF8Encoding(false)))
                {
                    respText = sr.ReadToEnd();
                }
            }
            catch (WebException wex)
            {
                string detail = "";
                try
                {
                    if (wex.Response != null)
                        using (var sr = new StreamReader(wex.Response.GetResponseStream(), new UTF8Encoding(false)))
                            detail = sr.ReadToEnd();
                }
                catch { }
                string hint = wex.Response == null
                    ? ("网络不可达: " + wex.Message)
                    : ("HTTP " + (int)((HttpWebResponse)wex.Response).StatusCode + " " + detail);
                throw new Exception("PaddleOCR-VL 请求失败: " + hint);
            }

            return ParseResponse(respText, crop.Width, crop.Height);
        }

        // ---- 响应解析(行拆分/清理逻辑与 GLM 一致,复用其 shared 方法) ----

        private List<OcrItem> ParseResponse(string respText, int cropW, int cropH)
        {
            var msg = _json.Deserialize<Dictionary<string, object>>(respText);
            if (msg == null) throw new Exception("千帆响应解析失败(空响应)");
            if (msg.ContainsKey("error"))
            {
                var err = msg["error"] as Dictionary<string, object>;
                string code = err != null && err.ContainsKey("code") ? Convert.ToString(err["code"]) : "?";
                string message = err != null && err.ContainsKey("message") ? Convert.ToString(err["message"]) : respText;
                throw new Exception("PaddleOCR-VL 错误 [" + code + "]: " + message);
            }

            var items = new List<OcrItem>();
            // result.layoutParsingResults[0].prunedResult.parsing_res_list
            var result = msg.ContainsKey("result") ? msg["result"] as Dictionary<string, object> : null;
            var layouts = result != null && result.ContainsKey("layoutParsingResults")
                ? result["layoutParsingResults"] as System.Collections.ArrayList : null;
            if (layouts == null || layouts.Count == 0)
                throw new Exception("PaddleOCR-VL 响应没有 layoutParsingResults(内容: " +
                    (respText.Length > 300 ? respText.Substring(0, 300) : respText) + ")");

            var first = layouts[0] as Dictionary<string, object>;
            var pruned = first != null && first.ContainsKey("prunedResult")
                ? first["prunedResult"] as Dictionary<string, object> : null;
            var blocks = pruned != null && pruned.ContainsKey("parsing_res_list")
                ? pruned["parsing_res_list"] as System.Collections.ArrayList : null;
            if (blocks == null) return items;

            foreach (Dictionary<string, object> b in blocks)
            {
                string label = b.ContainsKey("block_label") ? Convert.ToString(b["block_label"]) : "";
                string content = b.ContainsKey("block_content") ? Convert.ToString(b["block_content"]) : "";
                if (string.IsNullOrWhiteSpace(content)) continue;

                var bbox = b.ContainsKey("block_bbox") ? b["block_bbox"] as System.Collections.ArrayList : null;
                if (bbox == null || bbox.Count < 4) continue;

                // block_bbox 像素坐标 [x1,y1,x2,y2];裁剪到图内
                float x1 = Math.Max(0, Math.Min(cropW, Convert.ToSingle(bbox[0])));
                float y1 = Math.Max(0, Math.Min(cropH, Convert.ToSingle(bbox[1])));
                float x2 = Math.Max(0, Math.Min(cropW, Convert.ToSingle(bbox[2])));
                float y2 = Math.Max(0, Math.Min(cropH, Convert.ToSingle(bbox[3])));
                if (x2 - x1 < 2 || y2 - y1 < 2) continue;

                if (label == "table")
                {
                    AddTableItems(items, content, x1, y1, x2, y2);
                    continue;
                }
                if (label != "text" && label != "title" && label != "paragraph")
                    continue;   // 图片/公式/图表块跳过(title 也是文字,收)

                content = GlmOcrClient.CleanHtmlShared(content);
                if (string.IsNullOrWhiteSpace(content)) continue;

                string[] lines = content.Split(new[] { '\r', '\n' },
                    StringSplitOptions.RemoveEmptyEntries);
                float lineH = (y2 - y1) / lines.Length;
                float pad = Math.Min(lineH * 0.15f, 3f);
                for (int i = 0; i < lines.Length; i++)
                {
                    string text = GlmOcrClient.CleanMarkdownShared(lines[i]).Trim();
                    if (text.Length == 0) continue;
                    float ty1 = y1 + lineH * i + pad;
                    float ty2 = y1 + lineH * (i + 1) - pad;
                    if (ty2 - ty1 < 2) { ty1 = y1 + lineH * i; ty2 = ty1 + Math.Max(2, lineH); }
                    items.Add(new OcrItem
                    {
                        Text = text,
                        Box = new[]
                        {
                            new PointF(x1, ty1),
                            new PointF(x2, ty1),
                            new PointF(x2, ty2),
                            new PointF(x1, ty2)
                        },
                        Score = 1f
                    });
                }
            }
            return items;
        }

        private static readonly System.Text.RegularExpressions.Regex _trRegex =
            new System.Text.RegularExpressions.Regex("<tr[^>]*>(.*?)</tr>",
                System.Text.RegularExpressions.RegexOptions.Singleline |
                System.Text.RegularExpressions.RegexOptions.IgnoreCase |
                System.Text.RegularExpressions.RegexOptions.Compiled);
        private static readonly System.Text.RegularExpressions.Regex _tdRegex =
            new System.Text.RegularExpressions.Regex("<t[dh][^>]*>(.*?)</t[dh]>",
                System.Text.RegularExpressions.RegexOptions.Singleline |
                System.Text.RegularExpressions.RegexOptions.IgnoreCase |
                System.Text.RegularExpressions.RegexOptions.Compiled);

        /// <summary>表格块 → 每 tr 一条 item(td 内容空格拼接),行高均分 bbox。</summary>
        private static void AddTableItems(List<OcrItem> items, string tableHtml,
            float x1, float y1, float x2, float y2)
        {
            var rows = new List<string>();
            foreach (System.Text.RegularExpressions.Match tr in _trRegex.Matches(tableHtml))
            {
                var cells = new List<string>();
                foreach (System.Text.RegularExpressions.Match td in _tdRegex.Matches(tr.Groups[1].Value))
                {
                    string cell = GlmOcrClient.CleanHtmlShared(td.Groups[1].Value).Trim();
                    if (cell.Length > 0) cells.Add(cell);
                }
                if (cells.Count > 0) rows.Add(string.Join(" ", cells.ToArray()));
            }
            if (rows.Count == 0) return;
            float rowH = (y2 - y1) / rows.Count;
            float pad = Math.Min(rowH * 0.15f, 3f);
            for (int i = 0; i < rows.Count; i++)
            {
                float ty1 = y1 + rowH * i + pad;
                float ty2 = y1 + rowH * (i + 1) - pad;
                if (ty2 - ty1 < 2) { ty1 = y1 + rowH * i; ty2 = ty1 + Math.Max(2, rowH); }
                items.Add(new OcrItem
                {
                    Text = rows[i],
                    Box = new[]
                    {
                        new PointF(x1, ty1),
                        new PointF(x2, ty1),
                        new PointF(x2, ty2),
                        new PointF(x1, ty2)
                    },
                    Score = 1f
                });
            }
        }

        private void Notify(string s)
        {
            var h = StatusChanged;
            if (h != null) h(s);
        }
    }
}