package bjc.everge;

import java.util.*;
import java.util.function.*;
import java.util.regex.*;

import bjc.everge.ControlledString.*;

/**
 * String pairs for replacements.
 *
 * @author Ben Culkin
 */
public class ReplPair implements Comparable<ReplPair>, UnaryOperator<String> {
	// Line number we read this pair from
	private int lno;

	// Stage this pair is in
	private int stage;

	// Status of this pair with regards to doing staging stuff
	private StageStatus stat = StageStatus.BOTH;

	/**
	 * The priority for this replacement.
	 */
	public int priority;

	/**
	 * The name of this replacement.
	 *
	 * Defaults to the 'find' string.
	 */
	public String name;

	/**
	 * The guard for this replacement.
	 *
	 * The guard of the replacement is a regex that has to match before the pair
	 * will be considered. Defaults to being blank.
	 */
	public String guard;

	/**
	 * The string to look for.
	 */
	public String find;

	/**
	 * The string to replace it with.
	 */
	public String replace;

	/**
	 * Create a new blank replacement pair.
	 */
	public ReplPair() {
		this("", "", 1, null);
	}

	/**
	 * Create a new replacement pair with a priority of 1.
	 *
	 * @param f
	 *          The string to find.
	 * @param r
	 *          The string to replace.
	 */
	public ReplPair(String f, String r) {
		this(f, r, 1);
	}

	/**
	 * Create a new named replacement pair with a priority of 1.
	 *
	 * @param f
	 *          The string to find.
	 * @param r
	 *          The string to replace.
	 * @param n
	 *          The name of the replacement pair.
	 */
	public ReplPair(String f, String r, String n) {
		this(f, r, 1, n);
	}

	/**
	 * Create a new replacement pair with a set priority.
	 *
	 * @param f
	 *          The string to find.
	 * @param r
	 *          The string to replace.
	 * @param p
	 *          The priority for the replacement.
	 */
	public ReplPair(String f, String r, int p) {
		this(f, r, p, f);
	}

	/**
	 * Create a new replacement pair with a set priority and name.
	 *
	 * @param f
	 *          The string to find.
	 * @param r
	 *          The string to replace.
	 * @param n
	 *          The name of the replacement pair.
	 * @param p
	 *          The priority for the replacement.
	 */
	public ReplPair(String f, String r, int p, String n) {
		find = f;
		replace = r;

		name = n;

		priority = p;
	}

	/**
	 * Read a list of replacement pairs from an input source.
	 *
	 * @param scn
	 *            The source to read the replacements from.
	 * @return The list of replacements.
	 */
	public static List<ReplPair> readList(Scanner scn) {
		List<ReplPair> lst = new ArrayList<>();

		return readList(lst, scn);
	}

	/**
	 * Read a list of replacement pairs from an input source, adding them to an
	 * existing list.
	 *
	 * @param detals
	 *               The list to add the replacements to.
	 * @param scn
	 *               The source to read the replacements from.
	 * @return The list of replacements.
	 */
	public static List<ReplPair> readList(List<ReplPair> detals, Scanner scn) {
		List<ReplError> errList = new ArrayList<>();

		List<ReplPair> rplPar = readList(detals, scn, errList);

		if (errList.size() != 0) {
			throw new BadReplParse("", errList);
		}

		return rplPar;
	}

	/**
	 * Read a list of replacement pairs from an input source, adding them to an
	 * existing list.
	 *
	 * @param detals
	 *               The list to add the replacements to.
	 * @param scn
	 *               The source to read the replacements from.
	 * @param errs
	 *               The list to stick errors in.
	 * @return The list of replacements.
	 */
	public static List<ReplPair> readList(List<ReplPair> detals, Scanner scn,
			List<ReplError> errs) {
		return readList(detals, scn, errs, new ReplOpts());
	}

	/**
	 * Read a list of replacement pairs from an input source, adding them to an
	 * existing list.
	 *
	 * @param detals
	 *               The list to add the replacements to.
	 * @param scn
	 *               The source to read the replacements from.
	 * @param errs
	 *               The list to stick errors in.
	 * @param ropts
	 *               The options to use when reading the pairs.
	 * @return The list of replacements.
	 */
	public static List<ReplPair> readList(List<ReplPair> detals, Scanner scn,
			List<ReplError> errs, ReplOpts ropts) {
		IntHolder lno = new IntHolder();
		IntHolder pno = new IntHolder();

		List<List<ReplPair>> stages = new ArrayList<>();
		stages.add(new ArrayList<ReplPair>());

		// For every line in the source...
		while (scn.hasNextLine()) {
			String name = scn.nextLine().trim();
			lno.incr();

			// If its commented or blank, skip it
			if (name.equals(""))
				continue;
			if (name.startsWith("#"))
				continue;

			// Global control. Process it.
			if (name.startsWith("|//")) {
				readGlobal(name, scn, errs, ropts, lno, pno);

				continue;
			}

			ReplPair rp = new ReplPair();

			rp.priority = ropts.defPrior;
			rp.stat = ropts.defStatus;
			rp.lno = lno.get();
			rp.stage = ropts.defStage;

			boolean isMulti = ropts.defMulti;

			{
				String tmpName = readName(name, scn, errs, rp, ropts, lno, pno);
				if (tmpName == null)
					continue;
				name = tmpName;
			}

			rp.find = name;
			if (rp.name == null)
				rp.name = name;

			// We started to process the pair, mark it as being
			// started
			pno.incr();
			String body = null;

			// Read in the next uncommented line
			do {
				if (!scn.hasNextLine())
					break;

				body = scn.nextLine().trim();
				lno.incr();
			} while (body.startsWith("#"));

			if (body == null) {
				String msg = String.format(
						"Ran out of input looking for replacement body for raw name '%s'",
						name);

				errs.add(new ReplError(lno, pno, msg, null));
				break;
			}

			isMulti = ropts.defMulti;

			ControlledString cs = getControls(body, errs, ropts, lno, pno, "body");
			// Body has attached controls, process them.
			if (cs.hasControls()) {
				for (Control cont : cs.controls) {
					switch (cont.name) {
					case "MULTITRUE":
					case "MULTIT":
					case "MT":
						isMulti = true;
						break;
					case "MULTIFALSE":
					case "MULTIF":
					case "MF":
						isMulti = false;
						break;
					case "MULTI":
					case "M":
						if (cont.count() != 1) {
							String errMsg = String.format(
									"Expected one multi flag (got %d)", cont.count());
							errs.add(new ReplError(lno, pno, errMsg, body));
						} else {
							isMulti = Boolean.parseBoolean(cont.get(0));
						}
						break;
					default: {
						String errMsg
								= String.format("Invalid control name '%s'", cont.name);
						errs.add(new ReplError(lno, pno, errMsg, body));
					}
						break;
					}
				}

				body = cs.strang;
			}

			if (isMulti) {
				String tmp = readMultiLine(body, scn, ropts, "body", lno);
				if (tmp == null)
					continue;
				body = tmp;
			}

			rp.replace = body;

			List<ReplPair> stageList = null;
			if (rp.stage == 0 || stages.size() < (rp.stage - 1)) {
				stageList = stages.get(rp.stage);

				if (stageList == null) {
					stageList = new ArrayList<>();

					stages.add(rp.stage, stageList);
				}
			} else {
				for (int i = stages.size(); i <= rp.stage; i++) {
					stages.add(new ArrayList<>());
				}

				stageList = stages.get(rp.stage);
			}

			if (ropts.isTrace) {
				ropts.errStream.printf("\t[DEBUG] Stage %d: Added %s\n\t\tContents: %s\n",
						rp.stage, rp, stageList);
			}

			stageList.add(rp);
		}

		// Special-case one-stage processing.
		if (stages.size() == 1) {
			if (ropts.isTrace)
				ropts.errStream.printf("\t[DEBUG] Executing single-stage bypass\n");

			for (ReplPair rp : stages.iterator().next()) {
				if (rp.stat == StageStatus.INTERNAL) {
					if (ropts.isTrace)
						ropts.errStream.printf("\t[DEBUG] Excluding internal RP %s\n",
								rp);

					continue;
				}

				detals.add(rp);
			}

			detals.sort(null);

			return detals;
		}

		// Handle stages
		List<ReplPair> tmpList = new ArrayList<>();
		tmpList.addAll(detals);

		if (ropts.isTrace)
			ropts.errStream.printf("\t[DEBUG] Stages: %s\n", stages);

		int procStg = 0;
		for (List<ReplPair> stageList : stages) {
			procStg += 1;
			List<ReplPair> curStage = new ArrayList<>();

			if (ropts.isTrace)
				ropts.errStream.printf("\t[DEBUG] Staging stage %d of %d: %s\n", procStg,
						stageList.size(), stageList);

			for (ReplPair rp : stageList) {
				// Process through every pair in the previous
				// stages
				for (ReplPair curPar : tmpList) {
					String tmp = rp.replace.replaceAll(curPar.find, curPar.replace);

					if (ropts.isTrace && !rp.replace.equals(tmp)) {
						ropts.errStream.printf("\t[DEBUG] Staged '%s' -> '%s'\t%s\n",
								rp.replace, tmp, curPar);
					}

					rp.replace = tmp;
				}

				// If we're external; add straight to the output
				if (rp.stat == StageStatus.EXTERNAL) {
					if (ropts.isTrace) {
						ropts.errStream.printf(
								"\t[DEBUG] Skipped external for staging: %s\n", rp);
					}

					detals.add(rp);
				} else {
					if (ropts.isTrace) {
						ropts.errStream.printf(
								"\t[DEBUG] Added to stage %d: %s\n\t\tContents: %s\n",
								procStg, rp, curStage);
					}

					curStage.add(rp);
				}
			}

			tmpList.addAll(curStage);
			tmpList.sort(null);
		}

		// Copy over to output, excluding internals
		for (ReplPair rp : tmpList) {
			if (rp.stat == StageStatus.INTERNAL) {
				if (ropts.isTrace)
					ropts.errStream.printf("\t[DEBUG] Excluded internal: %s\n", rp);

				continue;
			}

			detals.add(rp);
		}

		detals.sort(null);

		if (ropts.isTrace) {
			ropts.errStream.printf("\t[DEBUG] Final output: %s\n", detals);
		}

		return detals;
	}

	private static String readMultiLine(String lead, Scanner src, ReplOpts ropts,
			String typ, IntHolder lno) {
		String tmp = lead;

		if (ropts.isTrace && tmp.endsWith("\\"))
			ropts.errStream.printf("\t[TRACE] Starting multi-line parse for %s '%s'\n",
					typ, tmp);

		boolean didMulti = tmp.endsWith("\\");
		while (tmp.endsWith("\\")) {
			boolean incNL = tmp.endsWith("|\\");

			if (!src.hasNextLine())
				break;

			String nxt = src.nextLine().trim();
			lno.incr();

			if (nxt.startsWith("#"))
				continue;

			String nlStr = incNL ? "\n" : "";

			if (tmp.endsWith("\\")) {
				if (incNL) {
					tmp = tmp.substring(0, tmp.length() - 2);
				} else {
					tmp = tmp.substring(0, tmp.length() - 1);
				}
			}

			tmp = String.format("%s%s%s", tmp, nlStr, nxt);
		}

		if (ropts.isTrace && didMulti)
			ropts.errStream.printf("\t[TRACE] Finished multi-line parse for %s:\n%s\n.\n",
					typ, tmp);

		return tmp;
	}

	@Override
	public String apply(String inp) {
		if (guard != null) {
			if (!inp.matches(guard))
				return inp;
		}

		// FIXME :EndingSlash Ben Culkin 5/20/20
		// In the event that replace ends with a \, that throws a confusing exception
		String res = inp.replaceAll(find, replace);

		return res;
	}

	@Override
	public String toString() {
		String nameStr = "";

		if (!find.equals(name))
			nameStr = String.format("(%s)", name);

		return String.format("%ss/(%s)/(%s)/p(%d)", nameStr, find, replace, priority);
	}

	@Override
	public int compareTo(ReplPair rp) {
		if (this.priority == rp.priority)
			return this.lno - rp.lno;

		return rp.priority - this.priority;
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((find == null) ? 0 : find.hashCode());
		result = prime * result + ((name == null) ? 0 : name.hashCode());
		result = prime * result + priority;
		result = prime * result + ((replace == null) ? 0 : replace.hashCode());
		result = prime * result + stage;
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		ReplPair other = (ReplPair) obj;
		if (find == null) {
			if (other.find != null)
				return false;
		} else if (!find.equals(other.find))
			return false;
		if (name == null) {
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		if (priority != other.priority)
			return false;
		if (replace == null) {
			if (other.replace != null)
				return false;
		} else if (!replace.equals(other.replace))
			return false;
		if (stage != other.stage)
			return false;
		return true;
	}

	private static String readName(String nam, Scanner scn, List<ReplError> errs,
			ReplPair rp, ReplOpts ropts, IntHolder lno, IntHolder pno) {
		ControlledString cs = getControls(nam, errs, ropts, lno, pno, "name");

		boolean isMulti = ropts.defMulti;

		String name = cs.strang;

		if (cs.hasControls()) {
			for (Control cont : cs.controls) {
				switch (cont.name) {
				case "NAME":
				case "N":
					if (cont.count() != 1) {
						String errMsg = String.format(
								"One name argument was expected (got %d)", cont.count());

						errs.add(new ReplError(lno, pno, errMsg, nam));
					} else {
						rp.name = cont.get(0);
					}
					break;
				case "GUARD":
				case "G":
					if (cont.count() != 1) {
						String errMsg = String.format(
								"One guard argument was expected (got %d)", cont.count());

						errs.add(new ReplError(lno, pno, errMsg, nam));
					} else {
						String pat = cont.get(0);

						try {
							Pattern.compile(pat);
						} catch (PatternSyntaxException psex) {
							String errMsg = String.format(
									"Guard argument '%s' is not a valid regex (%s)", pat,
									psex.getMessage());

							errs.add(new ReplError(lno, pno, errMsg, nam));
						}

						rp.guard = cont.get(0);
					}
					break;
				case "PRIORITY":
				case "PRIOR":
				case "P":
					try {
						if (cont.count() != 1) {
							String errMsg = String.format(
									"One priority argument was expected (got %d",
									cont.count());

							errs.add(new ReplError(lno, pno, errMsg, nam));
						} else {
							rp.priority = Integer.parseInt(cont.get(0));
						}
					} catch (NumberFormatException nfex) {
						String errMsg = String.format(
								"'%s' is not a valid priority (must be an integer)",
								cont.get(0));

						errs.add(new ReplError(lno, pno, errMsg, nam));
					}
					break;
				case "STAGE":
				case "S":
					try {
						if (cont.count() != 1) {
							String errMsg = String.format(
									"One stage argument was expected (got %d",
									cont.count());

							errs.add(new ReplError(lno, pno, errMsg, nam));
						} else {
							int tmpStage = Integer.parseInt(cont.get(0));
							if (tmpStage < 0) {
								String errMsg = String.format(
										"'%s' is not a valid stage (must be a positive integer)",
										cont.get(0));
								errs.add(new ReplError(lno, pno, errMsg, nam));

								break;
							}
							rp.stage = tmpStage;
						}
					} catch (NumberFormatException nfex) {
						String errMsg = String.format(
								"'%s' is not a valid stage (must be a positive integer)",
								cont.get(0));

						errs.add(new ReplError(lno, pno, errMsg, nam));
					}
					break;
				case "MULTITRUE":
				case "MULTIT":
				case "MT":
					isMulti = true;
					break;
				case "MULTIFALSE":
				case "MULTIF":
				case "MF":
					isMulti = false;
					break;
				case "MULTI":
				case "M":
					if (cont.count() != 1) {
						String errMsg = String.format(
								"One multi-flag argument was expected (got %d",
								cont.count());

						errs.add(new ReplError(lno, pno, errMsg, nam));
					} else {
						isMulti = Boolean.parseBoolean(cont.get(0));
					}
					break;
				case "INTERNAL":
				case "INT":
				case "I":
					rp.stat = StageStatus.INTERNAL;
					break;
				case "EXTERNAL":
				case "EXT":
				case "E":
					rp.stat = StageStatus.EXTERNAL;
					break;
				case "BOTH":
				case "B":
					rp.stat = StageStatus.BOTH;
					break;
				default: {
					String errMsg = String.format(
							"Unknown control name '%s' for name '%s'", cont.name, nam);

					ReplError erd = new ReplError(lno, pno, errMsg, nam);

					errs.add(erd);
				}
					break;
				}
			}

			name = cs.strang;
		}

		// Multi-line name with a trailer
		if (isMulti) {
			String tmp = readMultiLine(name, scn, ropts, "name", lno);
			if (tmp == null)
				return null;
			name = tmp;
		}

		return name;
	}

	private static void readGlobal(String nam, Scanner scn, List<ReplError> errs,
			ReplOpts ropts, IntHolder lno, IntHolder pno) {
		ControlledString cs
				= getControls(nam.substring(1), errs, ropts, lno, pno, "global");

		for (Control cont : cs.controls) {
			switch (cont.name) {
			case "PRIORITY":
			case "PRIOR":
			case "P":
				try {
					if (cont.count() != 1) {
						String errMsg = String.format(
								"Must specify 1 priority (%d specified)", cont.count());

						errs.add(new ReplError(lno, pno, errMsg, nam));
					} else {
						int tmp = Integer.parseInt(cont.get(0));
						ropts.defPrior = tmp;
					}
				} catch (NumberFormatException nfex) {
					String errMsg = String.format(
							"'%s' is not a valid priority (must be an integer)",
							cont.get(0));

					errs.add(new ReplError(lno, pno, errMsg, nam));
				}
				break;
			case "STAGE":
			case "S":
				try {
					if (cont.count() != 1) {
						String errMsg = String.format(
								"Must specify 1 stage (%d specified)", cont.count());

						errs.add(new ReplError(lno, pno, errMsg, nam));
					} else {
						int tmpStage = Integer.parseInt(cont.get(0));

						if (tmpStage < 0) {
							String errMsg = String.format(
									"'%s' is not a valid stage (must be a positive integer)",
									cont.get(0));

							errs.add(new ReplError(lno, pno, errMsg, nam));
							break;
						}

						ropts.defStage = tmpStage;
					}
				} catch (NumberFormatException nfex) {
					String errMsg = String.format(
							"'%s' is not a valid stage (must be a positive integer)",
							cont.get(0));

					errs.add(new ReplError(lno, pno, errMsg, nam));
				}
				break;
			case "MULTITRUE":
			case "MULTIT":
			case "MT":
				ropts.defMulti = true;
				break;
			case "MULTIFALSE":
			case "MULTIF":
			case "MF":
				ropts.defMulti = false;
				break;
			case "MULTI":
			case "M":
				if (cont.count() != 1) {
					String errMsg = String.format(
							"Must specify 1 multi-flag (%d specified)", cont.count());

					errs.add(new ReplError(lno, pno, errMsg, nam));
				} else {
					ropts.defMulti = Boolean.parseBoolean(cont.get(0));
				}
				break;
			case "INTERNAL":
			case "INT":
			case "I":
				ropts.defStatus = StageStatus.INTERNAL;
				break;
			case "EXTERNAL":
			case "EXT":
			case "E":
				ropts.defStatus = StageStatus.EXTERNAL;
				break;
			case "BOTH":
			case "B":
				ropts.defStatus = StageStatus.BOTH;
				break;
			case "DEBUGTRUE":
			case "DEBUGT":
			case "DT":
				ropts.isDebug = true;
				break;
			case "DEBUGFALSE":
			case "DEBUGF":
			case "DF":
				ropts.isDebug = false;
				break;
			case "DEBUG":
			case "D":
				if (cont.count() != 1) {
					String errMsg = String.format(
							"Must specify 1 debug flag (%d specified)", cont.count());

					errs.add(new ReplError(lno, pno, errMsg, nam));
				} else {
					ropts.isDebug = Boolean.parseBoolean(cont.get(0));
				}
				break;
			case "TRACETRUE":
			case "TRACET":
			case "TT":
				ropts.isTrace = true;
				break;
			case "TRACEFALSE":
			case "TRACEF":
			case "TF":
				ropts.isTrace = false;
				break;
			case "TRACE":
			case "T":
				if (cont.count() != 1) {
					String errMsg = String.format(
							"Must specify 1 trace flag (%d specified)", cont.count());

					errs.add(new ReplError(lno, pno, errMsg, nam));
				} else {
					ropts.isTrace = Boolean.parseBoolean(cont.get(0));
				}
				break;
			case "PERFTRUE":
			case "PERFT":
			case "PRFT":
				ropts.isPerf = true;
				break;
			case "PERFFALSE":
			case "PERFF":
			case "PRFF":
				ropts.isPerf = false;
				break;
			case "PERF":
			case "PRF":
				if (cont.count() != 1) {
					String errMsg = String.format(
							"Must specify 1 perf. flag (%d specified)", cont.count());

					errs.add(new ReplError(lno, pno, errMsg, nam));
				} else {
					ropts.isPerf = Boolean.parseBoolean(cont.get(0));
				}
				break;
			default: {
				String msg = String.format("Invalid global control name '%s'", cont.name);
				ReplError err = new ReplError(lno, pno, msg, nam);
				errs.add(err);
			}
				break;
			}

			if (ropts.isTrace)
				ropts.errStream.printf("\t[TRACE] Processed global control '%s'\n", cont);
		}

		return;
	}

	private static ControlledString getControls(String lne, List<ReplError> errs,
			ReplOpts ropts, IntHolder lno, IntHolder pno, String type) {
		try {
			return ControlledString.parse(lne, new ParseStrings("//", ";", "/", "|"));
		} catch (IllegalArgumentException iaex) {
			String msg = "Did not find control terminator (//) in %s where it should be";
			msg = String.format(msg, type);

			ReplError re = new ReplError(lno, pno, msg, lne);
			errs.add(re);

			return null;
		}
	}
}