#region Copyright & License Information
/*
 * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
 * This file is part of OpenRA, which is free software. It is made
 * available to you under the terms of the GNU General Public License
 * as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version. For more
 * information, see COPYING.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using OpenRA.Graphics;
using OpenRA.Mods.Common.Traits.Render;
using OpenRA.Traits;

namespace OpenRA.Mods.Common.Lint
{
	class CheckSequences : ILintRulesPass
	{
		void ILintRulesPass.Run(Action<string> emitError, Action<string> emitWarning, ModData modData, Ruleset rules)
		{
			// Custom maps define rules.Sequences, default mod rules leave it null.
			if (rules.Sequences == null)
			{
				foreach (var kv in modData.DefaultSequences)
				{
					Console.WriteLine("Testing default sequences for {0}", kv.Key);
					Run(emitError, emitWarning, rules, kv.Value);
				}
			}
			else if (!modData.DefaultSequences.Values.Contains(rules.Sequences))
				Run(emitError, emitWarning, rules, rules.Sequences);
		}

		void Run(Action<string> emitError, Action<string> emitWarning, Ruleset rules, SequenceProvider sequences)
		{
			var factions = rules.Actors["world"].TraitInfos<FactionInfo>().Select(f => f.InternalName).ToArray();
			foreach (var actorInfo in rules.Actors)
			{
				// Actors may have 0 or 1 RenderSprites traits
				var renderInfo = actorInfo.Value.TraitInfoOrDefault<RenderSpritesInfo>();
				if (renderInfo == null)
					continue;

				var images = new HashSet<string>()
				{
					renderInfo.GetImage(actorInfo.Value, sequences, null).ToLowerInvariant()
				};

				// Some actors define faction-specific artwork
				foreach (var faction in factions)
					images.Add(renderInfo.GetImage(actorInfo.Value, sequences, faction).ToLowerInvariant());

				foreach (var traitInfo in actorInfo.Value.TraitInfos<TraitInfo>())
				{
					// Remove the "Info" suffix
					var traitName = traitInfo.GetType().Name;
					traitName = traitName.Remove(traitName.Length - 4);

					var fields = traitInfo.GetType().GetFields();
					foreach (var field in fields)
					{
						var sequenceReference = field.GetCustomAttributes<SequenceReferenceAttribute>(true).FirstOrDefault();
						if (sequenceReference == null)
							continue;

						// Some sequences may specify their own Image override
						IEnumerable<string> sequenceImages = images;
						if (!string.IsNullOrEmpty(sequenceReference.ImageReference))
						{
							var imageField = fields.First(f => f.Name == sequenceReference.ImageReference);
							var imageOverride = (string)imageField.GetValue(traitInfo);
							if (string.IsNullOrEmpty(imageOverride))
							{
								if (!sequenceReference.AllowNullImage)
									emitError("Actor type `{0}` trait `{1}` must define a value for `{2}`".F(actorInfo.Value.Name, traitName, sequenceReference.ImageReference));
								continue;
							}

							sequenceImages = new[] { imageOverride.ToLowerInvariant() };
						}

						foreach (var sequence in LintExts.GetFieldValues(traitInfo, field, emitError, sequenceReference.DictionaryReference))
						{
							if (string.IsNullOrEmpty(sequence))
								continue;

							foreach (var i in sequenceImages)
							{
								if (sequenceReference.Prefix)
								{
									// TODO: Remove prefixed sequence references and instead use explicit lists of lintable references
									if (!sequences.Sequences(i).Any(s => s.StartsWith(sequence)))
										emitWarning("Actor type `{0}` trait `{1}` field `{2}` defines a prefix `{3}` that does not match any sequences on image `{4}`.".F(actorInfo.Value.Name, traitName, field.Name, sequence, i));
								}
								else if (!sequences.HasSequence(i, sequence))
									emitError("Actor type `{0}` trait `{1}` field `{2}` references an undefined sequence `{3}` on image `{4}`.".F(actorInfo.Value.Name, traitName, field.Name, sequence, i));
							}
						}
					}
				}
			}

			foreach (var weaponInfo in rules.Weapons)
			{
				var projectileInfo = weaponInfo.Value.Projectile;
				if (projectileInfo == null)
					continue;

				var fields = projectileInfo.GetType().GetFields();
				foreach (var field in fields)
				{
					var sequenceReference = field.GetCustomAttributes<SequenceReferenceAttribute>(true).FirstOrDefault();
					if (sequenceReference == null)
						continue;

					// All weapon sequences must specify their corresponding image
					var image = ((string)fields.First(f => f.Name == sequenceReference.ImageReference).GetValue(projectileInfo));
					if (string.IsNullOrEmpty(image))
					{
						if (!sequenceReference.AllowNullImage)
							emitError("Weapon type `{0}` projectile field `{1}` must define a value".F(weaponInfo.Key, sequenceReference.ImageReference));

						continue;
					}

					image = image.ToLowerInvariant();
					foreach (var sequence in LintExts.GetFieldValues(projectileInfo, field, emitError, sequenceReference.DictionaryReference))
					{
						if (string.IsNullOrEmpty(sequence))
							continue;

						if (sequenceReference.Prefix)
						{
							// TODO: Remove prefixed sequence references and instead use explicit lists of lintable references
							if (!sequences.Sequences(image).Any(s => s.StartsWith(sequence)))
								emitWarning("Weapon type `{0}` projectile field `{1}` defines a prefix `{2}` that does not match any sequences on image `{3}`.".F(weaponInfo.Key, field.Name, sequence, image));
						}
						else if (!sequences.HasSequence(image, sequence))
							emitError("Weapon type `{0}` projectile field `{1}` references an undefined sequence `{2}` on image `{3}`.".F(weaponInfo.Key, field.Name, sequence, image));
					}
				}
			}
		}
	}
}