// 
// NamingRule.cs
//  
// Author:
//       Michael Hutchinson <mhutch@xamarin.com>
//       Mike Krüger <mkrueger@xamarin.com>
// 
// Copyright (c) 2012 Xamarin <http://xamarin.com>
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using System;
using System.Linq;
using System.Text;
using System.Collections.Generic;

namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
	public class NamingRule : IEquatable<NamingRule>
	{
		public string Name { get; set; }
		/// <summary>
		/// If set, identifiers are required to be prefixed with one of these values.
		/// </summary>
		public string[] RequiredPrefixes { get; set; }

		/// <summary>
		/// If set, identifiers are allowed to be prefixed with one of these values.
		/// </summary>
		public string[] AllowedPrefixes { get; set; }

		/// <summary>
		/// If set, identifiers are required to be suffixed with one of these values.
		/// </summary>
		public string[] RequiredSuffixes { get; set; }

		/// <summary>
		/// If set, identifiers cannot be prefixed by any of these values.
		/// </summary>
		public string[] ForbiddenPrefixes { get; set; }

		/// <summary>
		/// If set, identifiers cannot be suffixed by with any of these values.
		/// </summary
		public string[] ForbiddenSuffixes { get; set; }

		/// <summary>
		/// Gets or sets the affected entity.
		/// </summary>
		public AffectedEntity AffectedEntity { get; set; } 

		/// <summary>
		/// Gets or sets the modifiers mask
		/// </summary>
		public Modifiers VisibilityMask { get; set; } 

		/// <summary>
		/// The way that the identifier is cased and that words are separated.
		/// </summary
		public NamingStyle NamingStyle { get; set; }

		public bool IncludeStaticEntities { get; set; }
		public bool IncludeInstanceMembers { get; set; }

		public bool IsValid(string name)
		{
			string id = name;
			bool foundPrefix = false;
			if (RequiredPrefixes != null && RequiredPrefixes.Length > 0) {
				var prefix = RequiredPrefixes.FirstOrDefault(p => id.StartsWith(p));
				if (prefix == null) {
					return false;
				}
				id = id.Substring(prefix.Length);
				foundPrefix = true;
			}
			
			if (!foundPrefix && AllowedPrefixes != null && AllowedPrefixes.Length > 0) {
				var prefix = AllowedPrefixes.FirstOrDefault(p => id.StartsWith(p));
				if (prefix != null) {
					id = id.Substring(prefix.Length);
					foundPrefix = true;
				}
			}
			
			if (!foundPrefix && ForbiddenPrefixes != null && ForbiddenPrefixes.Length > 0) {
				if (ForbiddenPrefixes.Any(p => id.StartsWith(p))) {
					return false;
				}
			}
			
			if (RequiredSuffixes != null && RequiredSuffixes.Length > 0) {
				var suffix = RequiredSuffixes.FirstOrDefault(s => id.EndsWith(s));
				if (suffix == null) {
					return false;
				}
				id = id.Substring(0, id.Length - suffix.Length);
			} else if (ForbiddenSuffixes != null && ForbiddenSuffixes.Length > 0) {
				if (ForbiddenSuffixes.Any(p => id.EndsWith(p))) {
					return false;
				}
			}
			
			switch (NamingStyle) {
				case NamingStyle.AllLower:
					return !id.Any(ch => char.IsLetter(ch) && char.IsUpper(ch));
				case NamingStyle.AllUpper:
					return !id.Any(ch => char.IsLetter(ch) && char.IsLower(ch));
				case NamingStyle.CamelCase:
					return id.Length == 0 || (char.IsLower(id [0]) && NoUnderscoreWithoutNumber(id));
				case NamingStyle.PascalCase:
					return id.Length == 0 || (char.IsUpper(id [0]) && NoUnderscoreWithoutNumber(id));
				case NamingStyle.FirstUpper:
					return id.Length == 0 && char.IsUpper(id [0]) && !id.Skip(1).Any(ch => char.IsLetter(ch) && char.IsUpper(ch));
			}
			return true;
		}

		public NamingRule(AffectedEntity affectedEntity)
		{
			AffectedEntity = affectedEntity;
			VisibilityMask = Modifiers.VisibilityMask;
			IncludeStaticEntities = true;
			IncludeInstanceMembers = true;
		}

		static bool NoUnderscoreWithoutNumber(string id)
		{
			int idx = id.IndexOf('_');
			while (idx >= 0 && idx < id.Length) {
				if ((idx + 2 >= id.Length || !char.IsDigit(id [idx + 1])) && (idx == 0 || !char.IsDigit(id [idx - 1]))) {
					return false;
				}
				idx = id.IndexOf('_', idx + 1);
			}
			return true;
		}


		public string GetErrorMessage(BaseRefactoringContext ctx, string name, out IList<string> suggestedNames)
		{
			suggestedNames = new List<string>();
			string id = name;
			
			string errorMessage = null;
			
			bool missingRequiredPrefix = false;
			bool missingRequiredSuffix = false;
			string requiredPrefix = null;
			string allowedPrefix = null;
			string suffix = null;
			
			if (AllowedPrefixes != null && AllowedPrefixes.Length > 0) {
				allowedPrefix = AllowedPrefixes.FirstOrDefault(p => id.StartsWith(p));
				if (allowedPrefix != null)
					id = id.Substring(allowedPrefix.Length);

			}

			if (RequiredPrefixes != null && RequiredPrefixes.Length > 0) {
				requiredPrefix = RequiredPrefixes.FirstOrDefault(p => id.StartsWith(p));
				if (requiredPrefix == null) {
					errorMessage = string.Format(ctx.TranslateString("Name should have prefix '{0}'."), RequiredPrefixes [0]);
					missingRequiredPrefix = true;
				} else {
					id = id.Substring(requiredPrefix.Length);
				}
			} else if (ForbiddenPrefixes != null && ForbiddenPrefixes.Length > 0) {
				requiredPrefix = ForbiddenPrefixes.FirstOrDefault(p => id.StartsWith(p));
				if (requiredPrefix != null) {
					errorMessage = string.Format(ctx.TranslateString("Name has forbidden prefix '{0}'."), requiredPrefix);
					id = id.Substring(requiredPrefix.Length);
				}
			}
			
			if (RequiredSuffixes != null && RequiredSuffixes.Length > 0) {
				suffix = RequiredSuffixes.FirstOrDefault(s => id.EndsWith(s));
				if (suffix == null) {
					errorMessage = string.Format(ctx.TranslateString("Name should have suffix '{0}'."), RequiredSuffixes [0]);
					missingRequiredSuffix = true;
				} else {
					id = id.Substring(0, id.Length - suffix.Length);
				}
			} else if (ForbiddenSuffixes != null && ForbiddenSuffixes.Length > 0) {
				suffix = ForbiddenSuffixes.FirstOrDefault(p => id.EndsWith(p));
				if (suffix != null) {
					errorMessage = string.Format(ctx.TranslateString("Name has forbidden suffix '{0}'."), suffix);
					id = id.Substring(0, id.Length - suffix.Length);
				}
			}
			
			switch (NamingStyle) {
				case NamingStyle.AllLower:
					if (id.Any(ch => char.IsLetter(ch) && char.IsUpper(ch))) {
						errorMessage = string.Format(ctx.TranslateString("'{0}' contains upper case letters."), name);
						suggestedNames.Add(LowerCaseIdentifier(WordParser.BreakWords(id)));
					} else {
						suggestedNames.Add(id);
					}
					break;
				case NamingStyle.AllUpper:
					if (id.Any(ch => char.IsLetter(ch) && char.IsLower(ch))) {
						errorMessage = string.Format(ctx.TranslateString("'{0}' contains lower case letters."), name);
						suggestedNames.Add(UpperCaseIdentifier(WordParser.BreakWords(id)));
					} else {
						suggestedNames.Add(id);
					}
					break;
				case NamingStyle.CamelCase:
					if (id.Length > 0 && char.IsUpper(id [0])) {
						errorMessage = string.Format(ctx.TranslateString("'{0}' should start with a lower case letter."), name);
					} else if (!NoUnderscoreWithoutNumber(id)) {
						errorMessage = string.Format(ctx.TranslateString("'{0}' should not separate words with an underscore."), name);
					} else {
						suggestedNames.Add(id);
						break;
					}
					suggestedNames.Add(CamelCaseIdentifier(WordParser.BreakWords(id)));
					break;
				case NamingStyle.PascalCase:
					if (id.Length > 0 && char.IsLower(id [0])) {
						errorMessage = string.Format(ctx.TranslateString("'{0}' should start with an upper case letter."), name);
					} else if (!NoUnderscoreWithoutNumber(id)) {
						errorMessage = string.Format(ctx.TranslateString("'{0}' should not separate words with an underscore."), name);
					} else {
						suggestedNames.Add(id);
						break;
					}
					suggestedNames.Add(PascalCaseIdentifier(WordParser.BreakWords(id)));
					break;
				case NamingStyle.FirstUpper:
					if (id.Length > 0 && char.IsLower(id [0])) {
						errorMessage = string.Format(ctx.TranslateString("'{0}' should start with an upper case letter."), name);
					} else if (id.Take(1).Any(ch => char.IsLetter(ch) && char.IsUpper(ch))) {
						errorMessage = string.Format(ctx.TranslateString("'{0}' contains an upper case letter after the first."), name);
					} else {
						suggestedNames.Add(id);
						break;
					}
					suggestedNames.Add(FirstUpperIdentifier(WordParser.BreakWords(id)));
					break;
			}

			if (requiredPrefix != null) {
				for (int i = 0; i < suggestedNames.Count; i++) {
					suggestedNames [i] = requiredPrefix + suggestedNames [i];
				}
			} else if (allowedPrefix != null) {
				int count = suggestedNames.Count;
				for (int i = 0; i < count; i++) {
					suggestedNames.Add(suggestedNames [i]);
					suggestedNames [i] = allowedPrefix + suggestedNames [i];
				}
			} else if (missingRequiredPrefix) {
				for (int i = 0; i < suggestedNames.Count; i++) {
					var n = suggestedNames [i];
					bool first = true;
					foreach (var p in RequiredPrefixes) {
						if (first) {
							first = false;
							suggestedNames [i] = p + n;
						} else {
							suggestedNames.Add(p + n);
						}
					}
				}
			}
			
			if (suffix != null) {
				for (int i = 0; i < suggestedNames.Count; i++) {
					suggestedNames [i] = suggestedNames [i] + suffix;
				}
			} else if (missingRequiredSuffix) {
				for (int i = 0; i < suggestedNames.Count; i++) {
					var n = suggestedNames [i];
					bool first = true;
					foreach (var s in RequiredSuffixes) {
						if (first) {
							first = false;
							suggestedNames [i] = n + s;
						} else {
							suggestedNames.Add(n + s);
						}
					}
				}
			}
			
			return errorMessage
			// should never happen.
				?? "no known errors.";
		}

		static string CamelCaseIdentifier (List<string> words)
		{
			var sb = new StringBuilder ();
			sb.Append (words[0].ToLower ());
			for (int i = 1; i < words.Count; i++) {
				if (sb.Length > 0 && (char.IsDigit (sb[sb.Length-1]) || char.IsDigit (words[i][0])))
					sb.Append ('_');
				AppendCapitalized (words[i], sb);
			}
			return sb.ToString ();
		}
		
		static string PascalCaseIdentifier (List<string> words)
		{
			var sb = new StringBuilder ();
			for (int i = 0; i < words.Count; i++) {
				if (sb.Length > 0 && (char.IsDigit (sb[sb.Length-1]) || char.IsDigit (words[i][0])))
					sb.Append ('_');
				AppendCapitalized (words[i], sb);
			}
			return sb.ToString ();
		}
		
		static string LowerCaseIdentifier (List<string> words)
		{
			var sb = new StringBuilder ();
			sb.Append (words[0].ToLower ());
			for (int i = 1; i < words.Count; i++) {
				sb.Append ('_');
				sb.Append (words[i].ToLower ());
			}
			return sb.ToString ();
		}
		
		static string UpperCaseIdentifier (List<string> words)
		{
			var sb = new StringBuilder ();
			sb.Append (words[0].ToUpper ());
			for (int i = 1; i < words.Count; i++) {
				sb.Append ('_');
				sb.Append (words[i].ToUpper ());
			}
			return sb.ToString ();
		}
		
		static string FirstUpperIdentifier (List<string> words)
		{
			var sb = new StringBuilder ();
			AppendCapitalized (words[0], sb);
			for (int i = 1; i < words.Count; i++) {
				sb.Append ('_');
				sb.Append (words[i].ToLower ());
			}
			return sb.ToString ();
		}
		
		static void AppendCapitalized(string word, StringBuilder sb)
		{
			sb.Append(word.ToLower());
			sb [sb.Length - word.Length] = char.ToUpper(sb [sb.Length - word.Length]);
		}

		#region IEquatable implementation
		public bool Equals (NamingRule other)
		{
			return Name == other.Name &&
				AffectedEntity == other.AffectedEntity && 
				VisibilityMask == other.VisibilityMask && 
				NamingStyle == other.NamingStyle;
		}
		#endregion

		public NamingRule Clone()
		{
			return (NamingRule)MemberwiseClone();
		}

		public override string ToString()
		{
			return string.Format("[NamingRule: Name={0}, AffectedEntity={1}, VisibilityMask={2}, NamingStyle={3}, IncludeStaticEntities={4}, IncludeInstanceMembers={5}]", Name, AffectedEntity, VisibilityMask, NamingStyle, IncludeStaticEntities, IncludeInstanceMembers);
		}
		
	}
}