using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.Text.RegularExpressions;
using System.Windows.Forms;

namespace YLPublishTool
{
    class Parser
    {
        int _nextPos;
        int _lineNum;
        int _lineStartPos;
        int _lineEndPos;
        string _source;
        StringReader _sr;

        bool _isGlobal;
        TreeNode _actionNode;
        List<TreeNode> _treeNodes;
        NameValueCollection _globalProperties;
        NameValueCollection _actionProperties;

        public IEnumerable<TreeNode> InnerParse(string source, NameValueCollection predefines = null)
        {
            _sr = new StringReader(_source = source);

            _nextPos = 0;
            _lineNum = 1;
            _lineStartPos = 0;
            _lineEndPos = 0;

            _isGlobal = false;
            _actionNode = null;
            _treeNodes = new List<TreeNode>();
            _globalProperties = predefines ?? new NameValueCollection();
            _actionProperties = new NameValueCollection();

            while (ReadLine(out string line))
            {
                ParseLine(line.TrimStart());
            }

            return _treeNodes;
        }

        private bool ReadLine(out string line)
        {
            line = null;
            _lineNum++;
            _lineStartPos = _nextPos;

            while (_sr.Peek() > 0)
            {
                _lineEndPos = _nextPos++;
                var ch = _sr.Read();
                var lineBreak = ch == '\r';
                if (lineBreak)
                {
                    if (_sr.Peek() == '\n')
                    {
                        _nextPos++;
                        _sr.Read();
                    }
                }
                else
                {
                    lineBreak = ch == '\n';
                }

                if (lineBreak)
                {
                    break;
                }
            }

            if (_lineEndPos >= _lineStartPos)
            {
                line = _source.Substring(_lineStartPos, _lineEndPos - _lineStartPos).TrimEnd();
                return true;
            }
            return false;
        }

        private void ParseLine(string line)
        {
            if (string.IsNullOrEmpty(line) || line[0] == '#')
            {
                return;
            }

            var tag = new ParseInfo {
                LineNum = _lineNum,
                OriginalText = line,
                ConvertedText = line,
                StartPos = _lineStartPos,
                EndPos = _lineEndPos
            };

            if (line[0] == '[')
            {
                _actionNode = new TreeNode(line) { Tag = tag };
                _treeNodes.Add(_actionNode);
                line = line.Trim(new[] { '[', ']' });
                _isGlobal = line == "全局变量";
                if (!_isGlobal && !Helper.ExistsAction(line))
                {
                    _actionNode.ForeColor = System.Drawing.Color.Red;
                    tag.ErrorInfo = "没有找到对应的指令处理器";
                }
                return;
            }

            if (_actionNode == null)
            {
                tag.ErrorInfo = "此处发生错误，脚本不会继续执行";
                _actionNode = new TreeNode("缺失[]指令") {
                    Tag = tag,
                    ForeColor = System.Drawing.Color.Red
                };
                _treeNodes.Add(_actionNode);
            }

            var tn = new TreeNode {
                Tag = tag
            };
            _actionNode.Nodes.Add(tn);

            var index = line.IndexOf('=');
            if (index < 0)
            {
                tn.Text = "无效行,忽略";
                tn.ForeColor = System.Drawing.Color.Red;
                return;
            }

            var left = line.Substring(0, index).TrimEnd();
            if (left.Length < 1)
            {
                tn.Text = "无效行,忽略";
                tn.ForeColor = System.Drawing.Color.Red;
                return;
            }

            index++;
            var right = line.Substring(index).TrimStart();

            if (right.StartsWith("#"))
            {
                tn.Text = "注释说明,忽略";
                tn.ForeColor = System.Drawing.Color.Red;
                return;
            }

            if (right.StartsWith("'''"))
            {
                var startPos = _lineStartPos + index;
                while (ReadLine(out string line2))
                {
                    if (line2.EndsWith("'''"))
                    {
                        break;
                    }
                }
                right = _source.Substring(startPos, _lineEndPos - startPos).Trim().Trim('\'');
            }
            tag.OriginalText = right;
            right = ConvertTemplateString(right);
            if (right.Length > 0)
            {
                (_isGlobal ? _globalProperties : _actionProperties)[left] = right;
            }
            tn.Text = left + " =";
            tag.ConvertedText = right;
            tag.EndPos = _lineEndPos;
        }

        private string ConvertTemplateString(string str)
        {
            if (string.IsNullOrEmpty(str) || str.IndexOf("${") < 0)
            {
                return str;
            }

            return Regex.Replace(str, @"\$\{(.+?)\}", m =>
            {
                var name = m.Groups[1].Value;
                return _actionProperties[name] ?? _globalProperties[name];
            });
        }
    }

    class ParseInfo
    {
        public int LineNum;
        public int StartPos;
        public int EndPos;
        public string OriginalText;
        public string ConvertedText;
        public string ErrorInfo;
    }
}