import {
  DiagnosticTarget,
  NoTarget,
  ServerHost,
  TypeSpecLanguageConfiguration,
} from "@typespec/compiler";
import * as monaco from "monaco-editor";
import { editor } from "monaco-editor";
import * as lsp from "vscode-languageserver";
import { DocumentHighlightKind, FormattingOptions } from "vscode-languageserver";
import { TextDocument } from "vscode-languageserver-textdocument";
import { BrowserHost } from "./browser-host.js";
import { importTypeSpecCompiler } from "./core.js";

function getIndentAction(
  value: "none" | "indent" | "indentOutdent" | "outdent"
): monaco.languages.IndentAction {
  switch (value) {
    case "none":
      return monaco.languages.IndentAction.None;
    case "indent":
      return monaco.languages.IndentAction.Indent;
    case "indentOutdent":
      return monaco.languages.IndentAction.IndentOutdent;
    case "outdent":
      return monaco.languages.IndentAction.Outdent;
  }
}

function getTypeSpecLanguageConfiguration(): monaco.languages.LanguageConfiguration {
  return {
    ...(TypeSpecLanguageConfiguration as any),
    onEnterRules: TypeSpecLanguageConfiguration.onEnterRules.map((rule) => {
      return {
        beforeText: new RegExp(rule.beforeText.pattern),
        previousLineText:
          "previousLineText" in rule ? new RegExp(rule.previousLineText.pattern) : undefined,
        action: {
          indentAction: getIndentAction(rule.action.indent),
          appendText: "appendText" in rule.action ? rule.action.appendText : undefined,
          removeText: "removeText" in rule.action ? rule.action.removeText : undefined,
        },
      };
    }),
  };
}

export async function registerMonacoLanguage(host: BrowserHost) {
  monaco.languages.register({ id: "typespec", extensions: [".tsp"] });
  monaco.languages.setLanguageConfiguration("typespec", getTypeSpecLanguageConfiguration());

  const serverHost: ServerHost = {
    compilerHost: host,
    getOpenDocumentByURL(url: string) {
      const model = monaco.editor.getModel(monaco.Uri.parse(url));
      return model ? textDocumentForModel(model) : undefined;
    },
    sendDiagnostics() {},
    // eslint-disable-next-line no-console
    log: console.log,
  };

  const { createServer } = await importTypeSpecCompiler();
  const serverLib = createServer(serverHost);
  const lsConfig = await serverLib.initialize({
    capabilities: {},
    processId: 1,
    workspaceFolders: [],
    rootUri: "inmemory://",
  });
  serverLib.initialized({});

  function textDocumentForModel(model: monaco.editor.IModel) {
    return TextDocument.create(
      model.uri.toString(),
      "typespec",
      model.getVersionId(),
      model.getValue()
    );
  }

  function lspDocumentArgs(model: monaco.editor.ITextModel) {
    return {
      textDocument: textDocumentForModel(model),
    };
  }

  function lspArgs(model: monaco.editor.ITextModel, pos: monaco.Position) {
    return {
      ...lspDocumentArgs(model),
      position: lspPosition(pos),
    };
  }

  function lspPosition(pos: monaco.Position): lsp.Position {
    return {
      line: pos.lineNumber - 1,
      character: pos.column - 1,
    };
  }

  function lspFormattingOptions(options: monaco.languages.FormattingOptions) {
    return FormattingOptions.create(options.tabSize, options.insertSpaces);
  }

  function monacoLocation(loc: lsp.Location): monaco.languages.Location {
    return {
      uri: monaco.Uri.parse(loc.uri),
      range: monacoRange(loc.range),
    };
  }

  function monacoDocumentHighlight(
    highlight: lsp.DocumentHighlight
  ): monaco.languages.DocumentHighlight {
    return {
      range: monacoRange(highlight.range),
      kind: monacoDocumentHighlightKind(highlight.kind),
    };
  }

  function monacoDocumentHighlightKind(kind: DocumentHighlightKind | undefined) {
    switch (kind) {
      case DocumentHighlightKind.Text:
        return monaco.languages.DocumentHighlightKind.Text;
      case DocumentHighlightKind.Read:
        return monaco.languages.DocumentHighlightKind.Read;
      case DocumentHighlightKind.Write:
        return monaco.languages.DocumentHighlightKind.Write;
      default:
        return undefined;
    }
  }

  function monacoHoverContents(contents: lsp.MarkupContent): monaco.IMarkdownString[] {
    return [{ value: contents.value }];
  }

  function monacoHover(hover: lsp.Hover): monaco.languages.Hover {
    // eslint-disable-next-line deprecation/deprecation
    if (Array.isArray(hover.contents) || lsp.MarkedString.is(hover.contents)) {
      throw new Error("MarkedString (deprecated) not supported.");
    }

    return {
      contents: monacoHoverContents(hover.contents),
      range: hover.range ? monacoRange(hover.range) : undefined,
    };
  }

  function monacoSignatureHelp(
    help: lsp.SignatureHelp | undefined
  ): monaco.languages.SignatureHelp {
    return {
      signatures:
        help?.signatures.map((x) => ({
          ...x,
          parameters: x.parameters ?? [],
        })) ?? [],
      activeSignature: help?.activeSignature ?? 0,
      activeParameter: help?.activeParameter ?? 0,
    };
  }

  function monacoRange(range: lsp.Range): monaco.IRange {
    return {
      startColumn: range.start.character + 1,
      startLineNumber: range.start.line + 1,
      endColumn: range.end.character + 1,
      endLineNumber: range.end.line + 1,
    };
  }

  function monacoFoldingRange(range: lsp.FoldingRange): monaco.languages.FoldingRange {
    return {
      start: range.startLine + 1,
      end: range.endLine + 1,
      kind: range.kind ? new monaco.languages.FoldingRangeKind(range.kind) : undefined,
    };
  }

  function monacoTextEdits(edit: lsp.TextEdit[]): monaco.languages.TextEdit[] {
    return edit.map(monacoTextEdit);
  }

  function monacoTextEdit(edit: lsp.TextEdit): monaco.languages.TextEdit {
    return {
      range: monacoRange(edit.range),
      text: edit.newText,
    };
  }

  function monacoWorkspaceEdit(edit: lsp.WorkspaceEdit): monaco.languages.WorkspaceEdit {
    const edits: monaco.languages.IWorkspaceTextEdit[] = [];
    for (const [uri, changes] of Object.entries(edit.changes ?? {})) {
      const resource = monaco.Uri.parse(uri);
      for (const change of changes) {
        edits.push({ resource, textEdit: monacoTextEdit(change), versionId: undefined });
      }
    }
    return { edits };
  }

  monaco.languages.registerDefinitionProvider("typespec", {
    async provideDefinition(model, position) {
      const results = await serverLib.gotoDefinition(lspArgs(model, position));
      return results.map(monacoLocation);
    },
  });

  monaco.languages.registerReferenceProvider("typespec", {
    async provideReferences(model, position, context) {
      const results = await serverLib.findReferences({ ...lspArgs(model, position), context });
      return results.map(monacoLocation);
    },
  });

  monaco.languages.registerRenameProvider("typespec", {
    async resolveRenameLocation(model, position): Promise<monaco.languages.RenameLocation> {
      const result = await serverLib.prepareRename(lspArgs(model, position));
      if (!result) {
        throw new Error("This element can't be renamed.");
      }
      const text = model.getWordAtPosition(position)?.word;
      if (!text) {
        throw new Error("Failed to obtain word at position.");
      }
      return { text, range: monacoRange(result) };
    },

    async provideRenameEdits(model, position, newName) {
      const result = await serverLib.rename({ ...lspArgs(model, position), newName });
      return monacoWorkspaceEdit(result);
    },
  });

  monaco.languages.registerFoldingRangeProvider("typespec", {
    async provideFoldingRanges(model) {
      const ranges = await serverLib.getFoldingRanges(lspDocumentArgs(model));
      const output = ranges.map(monacoFoldingRange);
      return output;
    },
  });

  monaco.languages.registerHoverProvider("typespec", {
    async provideHover(model, position) {
      const hover = await serverLib.getHover(lspArgs(model, position));
      return monacoHover(hover);
    },
  });

  monaco.languages.registerSignatureHelpProvider("typespec", {
    signatureHelpTriggerCharacters: ["(", ",", "<"],
    signatureHelpRetriggerCharacters: [")"],
    async provideSignatureHelp(model, position) {
      const help = await serverLib.getSignatureHelp(lspArgs(model, position));
      return { value: monacoSignatureHelp(help), dispose: () => {} };
    },
  });

  monaco.languages.registerDocumentFormattingEditProvider("typespec", {
    async provideDocumentFormattingEdits(model, options, token) {
      const edits = await serverLib.formatDocument({
        ...lspDocumentArgs(model),
        options: lspFormattingOptions(options),
      });
      return monacoTextEdits(edits);
    },
  });

  monaco.languages.registerDocumentHighlightProvider("typespec", {
    async provideDocumentHighlights(model, position) {
      const highlights = await serverLib.findDocumentHighlight(lspArgs(model, position));
      return highlights.map(monacoDocumentHighlight);
    },
  });

  monaco.languages.registerCompletionItemProvider("typespec", {
    triggerCharacters: lsConfig.capabilities.completionProvider!.triggerCharacters,
    async provideCompletionItems(model, position) {
      const result = await serverLib.complete(lspArgs(model, position));
      const word = model.getWordUntilPosition(position);
      const range = {
        startLineNumber: position.lineNumber,
        endLineNumber: position.lineNumber,
        startColumn: word.startColumn,
        endColumn: word.endColumn,
      };

      const suggestions: monaco.languages.CompletionItem[] = [];
      for (const item of result.items) {
        suggestions.push({
          label: item.label,
          kind: item.kind as any,
          documentation: item.documentation,
          insertText: item.insertText!,
          range,
          commitCharacters:
            item.commitCharacters ?? lsConfig.capabilities.completionProvider!.allCommitCharacters,
          tags: item.tags,
        });
      }

      return { suggestions };
    },
  });

  monaco.editor.defineTheme("typespec", {
    base: "vs",
    inherit: true,
    colors: {},
    rules: [
      { token: "macro", foreground: "#800000" },
      { token: "function", foreground: "#795E26" },
    ],
  });
  monaco.editor.setTheme("typespec");

  monaco.languages.registerDocumentSemanticTokensProvider("typespec", {
    getLegend() {
      const legend = lsConfig.capabilities.semanticTokensProvider!.legend;
      return {
        tokenModifiers: legend.tokenModifiers,
        tokenTypes: legend.tokenTypes.map((entry) => {
          switch (entry) {
            case "namespace":
            case "class":
            case "enum":
            case "typeParameter":
            case "struct":
            case "interface":
              return "type";
            case "property":
            case "enumMember":
              return "variable";
            case "docCommentTag":
              return "keyword";
            default:
              return entry;
          }
        }),
      };
    },
    async provideDocumentSemanticTokens(model) {
      const result = await serverLib.buildSemanticTokens(lspDocumentArgs(model));
      return {
        resultId: result.resultId,
        data: new Uint32Array(result.data),
      };
    },
    releaseDocumentSemanticTokens() {},
  });
}

export function getMarkerLocation(
  typespecCompiler: typeof import("@typespec/compiler"),
  target: DiagnosticTarget | typeof NoTarget
): Pick<editor.IMarkerData, "startLineNumber" | "startColumn" | "endLineNumber" | "endColumn"> {
  const loc = typespecCompiler.getSourceLocation(target);
  if (loc === undefined || loc.file.path !== "/test/main.tsp") {
    return {
      startLineNumber: 1,
      startColumn: 1,
      endLineNumber: 1,
      endColumn: 1,
    };
  }
  const start = loc.file.getLineAndCharacterOfPosition(loc.pos);
  const end = loc.file.getLineAndCharacterOfPosition(loc.end);
  return {
    startLineNumber: start.line + 1,
    startColumn: start.character + 1,
    endLineNumber: end.line + 1,
    endColumn: end.character + 1,
  };
}
