/*
 This file is part of GNU Taler
 (C) 2022 Taler Systems S.A.

 GNU Taler is free software; you can redistribute it and/or modify it under the
 terms of the GNU General Public License as published by the Free Software
 Foundation; either version 3, or (at your option) any later version.

 GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

 You should have received a copy of the GNU General Public License along with
 GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */

import * as ts from "typescript";
import * as fs from "fs/promises";
import * as path from "path";
import * as prettier from "prettier";

if (process.argv.length != 4) {
  console.log(
    `usage: ${process.argv[0]} ${process.argv[1]} WALLET_CORE_REPO OUTFILE`
  );
  process.exit(2);
}

const walletRootDir = process.argv[2];
const outfile = process.argv[3];

const walletCoreDir = path.join(walletRootDir, "packages/taler-wallet-core");
const excludedNames = new Set([
  "TalerErrorCode",
  "WalletBackupContentV1",
  "Array",
]);

const configFile = ts.findConfigFile(
  walletCoreDir,
  ts.sys.fileExists,
  "tsconfig.json"
);
if (!configFile) throw Error("tsconfig.json not found");
const { config } = ts.readConfigFile(configFile, ts.sys.readFile);

const { options, fileNames, errors } = ts.parseJsonConfigFileContent(
  config,
  ts.sys,
  walletCoreDir
);

const program = ts.createProgram({
  options,
  rootNames: fileNames,
  configFileParsingDiagnostics: errors,
});

const checker = program.getTypeChecker();

const walletApiTypesFiles = `${walletCoreDir}/src/wallet-api-types.ts`;
console.log("api types file:", walletApiTypesFiles);

const sourceFile = program.getSourceFile(walletApiTypesFiles);

if (!sourceFile) {
  throw Error();
}

const printer = ts.createPrinter({ newLine: ts.NewLineKind.LineFeed });

const fileSymbol = program.getTypeChecker().getSymbolAtLocation(sourceFile);

const expo = fileSymbol?.exports;
if (!expo) {
  throw Error();
}

interface PerOpGatherState {
  opName: string;
  nameSet: Set<string>;
  group: string;
  /**
   * Enum member declaration in the form 'Foo = "bar"'.
   */
  enumMemberDecl: string | undefined;
}

interface GatherState {
  declTexts: Map<string, string>;
}

function gatherDecls(
  node: ts.Node,
  gatherState: GatherState,
  perOpState: PerOpGatherState
): void {
  switch (node.kind) {
    case ts.SyntaxKind.EnumDeclaration:
      // Always handled via parent
      return;
    case ts.SyntaxKind.Identifier:
    case ts.SyntaxKind.TypeReference: {
      console.log(`start typeref-or-id ${node.getText()}`);
      const type = checker.getTypeAtLocation(node);
      if (type.flags === ts.TypeFlags.String) {
        console.log("string!");
        break;
      }
      const symbol = type.symbol || type.aliasSymbol;
      if (!symbol) {
        console.log(`no type symbol for ${node.getText()}`);
        break;
      }
      const name = symbol.name;
      console.log(`symbol name: ${type.symbol?.name}`);
      console.log(`alias symbol name: ${type.aliasSymbol?.name}`);
      if (perOpState.nameSet.has(name)) {
        console.log("already found!");
        break;
      }
      perOpState.nameSet.add(name);
      if (excludedNames.has(name)) {
        console.log("excluded!");
        break;
      }
      const decls = symbol.getDeclarations();
      decls?.forEach((decl) => {
        const sourceFilename = decl.getSourceFile().fileName;
        if (path.basename(sourceFilename).startsWith("lib.")) {
          return;
        }
        switch (decl.kind) {
          case ts.SyntaxKind.EnumMember: {
            gatherDecls(decl.parent, gatherState, perOpState);
            console.log("enum member", decl.getText());
            break;
          }
          case ts.SyntaxKind.InterfaceDeclaration:
          case ts.SyntaxKind.EnumDeclaration:
          case ts.SyntaxKind.TypeAliasDeclaration: {
            const declText = printer.printNode(
              ts.EmitHint.Unspecified,
              decl,
              decl.getSourceFile()!
            );
            gatherState.declTexts.set(name, declText);
            console.log(declText);
            break;
          }
          default:
            console.log(`unknown decl kind ${ts.SyntaxKind[decl.kind]}`);
            break;
        }
        gatherDecls(decl, gatherState, perOpState);
        console.log(`end typeref-or-id ${node.getText()}`);
      });
      break;
    }
    default:
      break;
  }
  console.log(`syntax children for ${node.getText()}`);
  node.forEachChild((child) => {
    console.log(`syntax child: ${ts.SyntaxKind[child.kind]}`);
    gatherDecls(child, gatherState, perOpState);
  });
  //console.log(`// unknown node kind ${ts.SyntaxKind[node.kind]}`);
  return;
}

function getOpEnumDecl(decl: ts.Declaration): string | undefined {
  let enumMemberDecl: undefined | string = undefined;
  function walk(node: ts.Node) {
    node.forEachChild((x) => {
      console.log(`child kind: ${ts.SyntaxKind[x.kind]}`);
      console.log(x.getText());
      switch (x.kind) {
        case ts.SyntaxKind.PropertySignature: {
          const sig = x as ts.PropertySignature;
          if (sig.name.getText() == "op") {
            const type = checker.getTypeFromTypeNode(sig.type!);
            enumMemberDecl = type.symbol.declarations![0]!.getText();
          }
          break;
        }
      }
      walk(x);
    });
  }
  walk(decl);
  return enumMemberDecl;
}

const main = async () => {
  const f = await fs.open(outfile, "w");
  const gatherState: GatherState = {
    declTexts: new Map<string, string>(),
  };
  const perOpStates: PerOpGatherState[] = [];

  let currentGroup: string = "Unknown Group";

  expo.forEach((v, k) => {
    if (!v.name.endsWith("Op")) {
      return;
    }
    const decls = v.getDeclarations();
    decls?.forEach((decl) => {
      console.log(`export decl, kind ${ts.SyntaxKind[decl.kind]}`);

      const commentRanges = ts.getLeadingCommentRanges(
        sourceFile.getFullText(),
        decl.getFullStart()
      );
      commentRanges?.forEach((r) => {
        const text = sourceFile.getFullText().slice(r.pos, r.end);
        console.log("comment text:", text);
        const groupPrefix = "group:";
        const loc = text.indexOf(groupPrefix);
        if (loc >= 0) {
          const groupName = text.slice(loc + groupPrefix.length);
          console.log("got new group", groupName);
          currentGroup = groupName;
        }
      });

      const perOpState: PerOpGatherState = {
        opName: v.name,
        nameSet: new Set<string>(),
        group: currentGroup,
        enumMemberDecl: getOpEnumDecl(decl),
      };
      let declText = printer.printNode(
        ts.EmitHint.Unspecified,
        decl,
        decl.getSourceFile()!
      );
      if (perOpState.enumMemberDecl) {
        declText = declText + `\n// ${perOpState.enumMemberDecl}\n`;
      }
      console.log("replacing group in", declText);
      // Remove group comments
      declText = declText.replace(/\/\/ group: [^\n]*[\n]/m, "");
      perOpState.nameSet.add(v.name);
      gatherState.declTexts.set(v.name, declText);
      gatherDecls(decl, gatherState, perOpState);
      perOpStates.push(perOpState);
    });
  });

  const allNames: Set<string> = new Set();

  for (const g of perOpStates) {
    for (const k of g.nameSet.values()) {
      allNames.add(k);
    }
  }

  const commonNames: Set<string> = new Set();

  for (const name of allNames) {
    let count = 0;
    for (const g of perOpStates) {
      for (const k of g.nameSet.values()) {
        if (name === k) {
          count++;
        }
      }
    }
    if (count > 1) {
      console.log(`common name: ${name}`);
      commonNames.add(name);
    }
  }

  const groups = new Set<string>();
  for (const g of perOpStates) {
    groups.add(g.group);
  }

  await f.write(`# Wallet-Core API Documentation\n`);

  await f.write(
    `This file is auto-generated from [wallet-core](https://git.taler.net/wallet-core.git/tree/packages/taler-wallet-core/src/wallet-api-types.ts).\n`
  );

  await f.write(`## Overview\n`);
  for (const g of groups.values()) {
    await f.write(`### ${g}\n`);
    for (const op of perOpStates) {
      if (op.group !== g) {
        continue;
      }
      await f.write(`* [${op.opName}](#${op.opName.toLowerCase()})\n`);
    }
  }

  await f.write(`## Operation Reference\n`);
  for (const g of perOpStates) {
    // Not yet supported, switch to myst first!
    // await f.write(`(${g.opName.toLowerCase()})=\n`);
    await f.write(`### ${g.opName}\n`);
    for (const name of g.nameSet.values()) {
      if (commonNames.has(name)) {
        continue;
      }
      const text = gatherState.declTexts.get(name);
      if (!text) {
        continue;
      }
      await f.write("```typescript\n");
      const formatted = prettier.format(text, {
        semi: true,
        parser: "typescript",
      });
      await f.write(`${formatted}\n`);
      await f.write("```\n");
    }
    await f.write("\n");
  }

  await f.write(`## Common Declarations\n`);
  for (const name of commonNames.values()) {
    const text = gatherState.declTexts.get(name);
    if (!text) {
      continue;
    }
    await f.write("```typescript\n");
    const formatted = prettier.format(text, {
      semi: true,
      parser: "typescript",
    });
    await f.write(`${formatted}`);
    await f.write("```\n");
  }

  await f.close();
};

main();