import { filterLocalSymbols, FishDocumentSymbol, isGlobalSymbol, isUniversalSymbol, symbolIsImmutable } from './document-symbol';
import { Analyzer } from './analyze';
import { LspDocument } from './document';
import { Position, Location, Range, SymbolKind, TextEdit, DocumentUri, WorkspaceEdit, RenameFile } from 'vscode-languageserver';
import { getChildNodes, getRange } from './utils/tree-sitter';
import { SyntaxNode } from 'web-tree-sitter';
import { isCommandName } from './utils/node-types';

export function containsRange(range: Range, otherRange: Range): boolean {
  if (otherRange.start.line < range.start.line || otherRange.end.line < range.start.line) {
    return false;
  }
  if (otherRange.start.line > range.end.line || otherRange.end.line > range.end.line) {
    return false;
  }
  if (otherRange.start.line === range.start.line && otherRange.start.character < range.start.character) {
    return false;
  }
  if (otherRange.end.line === range.end.line && otherRange.end.character > range.end.character) {
    return false;
  }
  return true;
}

export function precedesRange(before: Range, after: Range): boolean {
  if (before.start.line < after.start.line) {
    return true;
  }
  if (before.start.line === after.start.line && before.start.character < after.start.character) {
    return true;
  }
  return false;
}

export function canRenamePosition(analyzer: Analyzer, document: LspDocument, position: Position): boolean {
  return !!analyzer.findDocumentSymbol(document, position);
}

export type RenameSymbolType = 'local' | 'global';

export function getRenameSymbolType(analyzer: Analyzer, document: LspDocument, position: Position): RenameSymbolType {
  const symbol = analyzer.findDocumentSymbol(document, position);
  if (!symbol) {
    return 'local';
  }

  if (isGlobalSymbol(symbol) || isUniversalSymbol(symbol)) {
    return 'global';
  }
  return 'local';
}

export type RenameChanges = {
  [uri: DocumentUri]: TextEdit[];
};

function findLocations(uri: string, nodes: SyntaxNode[], matchName: string): Location[] {
  const equalRanges = (a: Range, b: Range) => {
    return (
      a.start.line === b.start.line &&
            a.start.character === b.start.character &&
            a.end.line === b.end.line &&
            a.end.character === b.end.character
    );
  };
  const matchingNames = nodes.filter(node => node.text === matchName);
  const uniqueRanges: Range[] = [];
  matchingNames.forEach(node => {
    const range = getRange(node);
    if (uniqueRanges.some(u => equalRanges(u, range))) {
      return;
    }
    uniqueRanges.push(range);
  });
  return uniqueRanges.map(range => Location.create(uri, range));
}

function findLocalLocations(analyzer: Analyzer, document: LspDocument, position: Position): Location[] {
  const symbol = findDefinitionSymbols(analyzer, document, position).pop();
  if (!symbol) {
    return [];
  }
  const nodesToSearch = getChildNodes(symbol.scope.scopeNode);
  return findLocations(document.uri, nodesToSearch, symbol.name);
}

function removeLocalSymbols(matchSymbol: FishDocumentSymbol, nodes: SyntaxNode[], symbols: FishDocumentSymbol[]) {
  const name = matchSymbol.name;
  const matchingSymbols = filterLocalSymbols(symbols.filter(symbol => symbol.name === name)).map(symbol => symbol.scope.scopeNode);
  const matchingNodes = nodes.filter(node => node.text === name);

  if (matchingSymbols.length === 0 || matchSymbol.kind === SymbolKind.Function) {
    return matchingNodes;
  }

  return matchingNodes.filter((node) => {
    if (matchingSymbols.some(scopeNode => containsRange(getRange(scopeNode), getRange(node)))) {
      return false;
    }
    return true;
  });
}
function findGlobalLocations(analyzer: Analyzer, document: LspDocument, position: Position): Location[] {
  const locations: Location[] = [];
  const symbol = analyzer.findDocumentSymbol(document, position);
  if (!symbol) {
    return [];
  }
  const uris = analyzer.cache.uris();
  for (const uri of uris) {
    const doc = analyzer.getDocument(uri)!;
    if (!doc.isAutoloaded()) {
      continue;
    }
    const rootNode = analyzer.getRootNode(doc)!;
    const toSearchNodes = removeLocalSymbols(symbol, getChildNodes(rootNode), analyzer.cache.getFlatDocumentSymbols(uri));
    const newLocations = findLocations(uri, toSearchNodes, symbol.name);
    locations.push(...newLocations);
  }
  return locations;
}

export function getRenameLocations(analyzer: Analyzer, document: LspDocument, position: Position): Location[] {
  if (!canRenamePosition(analyzer, document, position)) {
    return [];
  }
  const renameScope = getRenameSymbolType(analyzer, document, position);
  switch (renameScope) {
    case 'local':
      return findLocalLocations(analyzer, document, position);
    case 'global':
      return findGlobalLocations(analyzer, document, position);
    default:
      return [];
  }
}

export function getReferenceLocations(analyzer: Analyzer, document: LspDocument, position: Position): Location[] {
  const node = analyzer.nodeAtPoint(document.uri, position.line, position.character);
  if (!node) return [];
  const symbol = analyzer.getDefinition(document, position);
  if (symbol) {
    const doc = analyzer.getDocument(symbol.uri)!;
    const { scopeTag } = symbol.scope;
    switch (scopeTag) {
      case 'global':
      case 'universal':
        return findGlobalLocations(analyzer, doc, symbol.selectionRange.start);
      case 'local':
      default:
        return findLocalLocations(analyzer, document, symbol.selectionRange.start);
    }
  }
  if (isCommandName(node)) {
    const uris = analyzer.cache.uris();
    const locations: Location[] = [];
    for (const uri of uris) {
      const doc = analyzer.getDocument(uri)!;
      const rootNode = analyzer.getRootNode(doc)!;
      const nodes = getChildNodes(rootNode).filter(n => isCommandName(n));
      const newLocations = findLocations(uri, nodes, node.text);
      locations.push(...newLocations);
    }
    return locations;
  }
  return [];
}

const createRenameFile = (oldUri: DocumentUri, newUri: DocumentUri): RenameFile => {
  return {
    kind: 'rename',
    oldUri,
    newUri,
  };
};

export function getRenameFiles(analyzer: Analyzer, document: LspDocument, position: Position, newName: string): RenameFile[] | null {
  const renameFiles: RenameFile[] = [];
  const symbol = analyzer.findDocumentSymbol(document, position);
  if (!symbol) {
    return null;
  }
  if (symbol.kind !== SymbolKind.Function) {
    return null;
  }
  if (symbolIsImmutable(symbol)) {
    return null;
  }
  if (symbol.scope.scopeTag === 'global') {
    analyzer.getExistingAutoloadedFiles(symbol.name).forEach(uri => {
      const newUri = uri.replace(symbol.name, newName);
      renameFiles.push(createRenameFile(uri, newUri));
    });
  }
  return renameFiles;
}
export function getRenameWorkspaceEdit(analyzer: Analyzer, document: LspDocument, position: Position, newName: string): WorkspaceEdit | null {
  const locations = getRenameLocations(analyzer, document, position);
  if (!locations || locations.length === 0) {
    return null;
  }

  const changes: RenameChanges = {};

  for (const location of locations) {
    const uri = location.uri;
    const edits = changes[uri] || [];
    edits.push(TextEdit.replace(location.range, newName));
    changes[uri] = edits;
  }

  const documentChanges: RenameFile[] | null = getRenameFiles(analyzer, document, position, newName);
  if (documentChanges && documentChanges.length > 0) {
    return { changes, documentChanges };
  }

  return { changes };
}

export function findDefinitionSymbols(analyzer: Analyzer, document: LspDocument, position: Position): FishDocumentSymbol[] {
  const symbols: FishDocumentSymbol[] = [];
  const localSymbols = analyzer.getFlatDocumentSymbols(document.uri);
  const toFind = analyzer.nodeAtPoint(document.uri, position.line, position.character);
  if (!toFind) {
    return [];
  }
  const localSymbol = analyzer.findDocumentSymbol(document, position);
  if (localSymbol) {
    symbols.push(localSymbol);
  } else {
    const toAdd: FishDocumentSymbol[] = localSymbols.filter((s) => {
      const variableBefore = s.kind === SymbolKind.Variable ? precedesRange(s.selectionRange, getRange(toFind)) : true;
      return (
        s.name === toFind.text
                && containsRange(
                  getRange(s.scope.scopeNode),
                  getRange(toFind),
                )
                && variableBefore
      );
    });
    symbols.push(...toAdd);
  }
  if (!symbols.length) {
    symbols.push(...analyzer.globalSymbols.find(toFind.text));
  }
  return symbols;
}