import * as fs from 'fs';
import * as path from 'path';
import type { CsoundReference } from './types';

export class TypeScriptGenerator {
  private outputDir: string;

  constructor(outputDir: string) {
    this.outputDir = outputDir;
  }

  sanitizeCategoryName(category: string): string {
    return category
      .toLowerCase()
      .replace(/[^a-z0-9]+/g, '-')
      .replace(/^-+|-+$/g, '');
  }

  sanitizeVariableName(category: string): string {
    return category
      .replace(/[^a-zA-Z0-9]+/g, ' ')
      .split(' ')
      .map((word, index) =>
        index === 0
          ? word.toLowerCase()
          : word.charAt(0).toUpperCase() + word.slice(1).toLowerCase()
      )
      .join('')
      .replace(/^[0-9]/, '_$&');
  }

  escapeString(str: string): string {
    return str
      .replace(/\\/g, '\\\\')
      .replace(/'/g, "\\'")
      .replace(/\n/g, '\\n')
      .replace(/\r/g, '\\r')
      .replace(/\t/g, '\\t');
  }

  generateReferenceObject(ref: CsoundReference, indent: string = '  '): string {
    const lines: string[] = [];
    lines.push(`{`);
    lines.push(`${indent}name: '${this.escapeString(ref.name)}',`);
    lines.push(`${indent}type: '${ref.type}',`);
    lines.push(`${indent}category: '${this.escapeString(ref.category)}',`);
    lines.push(`${indent}description: '${this.escapeString(ref.description)}',`);

    if (ref.syntax) {
      lines.push(`${indent}syntax: '${this.escapeString(ref.syntax)}',`);
    }

    if (ref.example) {
      const escapedExample = this.escapeString(ref.example);
      lines.push(`${indent}example: '${escapedExample}',`);
    }

    if (ref.rates && ref.rates.length > 0) {
      lines.push(`${indent}rates: [${ref.rates.map(r => `'${r}'`).join(', ')}],`);
    }

    if (ref.parameters && ref.parameters.length > 0) {
      lines.push(`${indent}parameters: [`);
      for (const param of ref.parameters) {
        lines.push(`${indent}  {`);
        lines.push(`${indent}    name: '${this.escapeString(param.name)}',`);
        lines.push(`${indent}    description: '${this.escapeString(param.description)}',`);
        lines.push(`${indent}    type: '${param.type}'`);
        lines.push(`${indent}  },`);
      }
      lines.push(`${indent}],`);
    }

    if (ref.seeAlso && ref.seeAlso.length > 0) {
      lines.push(`${indent}seeAlso: [${ref.seeAlso.map(s => `'${this.escapeString(s)}'`).join(', ')}]`);
    }

    lines.push(`}`);
    return lines.join('\n');
  }

  generateCategoryFile(
    category: string,
    references: CsoundReference[],
    fileName: string
  ): string {
    const varName = this.sanitizeVariableName(category);

    const lines: string[] = [];
    lines.push(`import type { CsoundReference } from './types'`);
    lines.push(``);
    lines.push(`// ${category}`);
    lines.push(`export const ${varName}: CsoundReference[] = [`);

    for (const ref of references) {
      const refLines = this.generateReferenceObject(ref, '  ');
      lines.push(refLines + ',');
    }

    lines.push(`]`);
    lines.push(``);

    return lines.join('\n');
  }

  generateMainFile(categories: Map<string, CsoundReference[]>): string {
    const lines: string[] = [];

    lines.push(`import type { CsoundReference } from './types'`);

    const imports: string[] = [];
    const varNames: string[] = [];

    for (const [category] of categories) {
      const fileName = this.sanitizeCategoryName(category);
      const varName = this.sanitizeVariableName(category);
      imports.push(`import { ${varName} } from './${fileName}'`);
      varNames.push(varName);
    }

    lines.push(...imports);
    lines.push(``);
    lines.push(`export type { CsoundReference }`);
    lines.push(``);
    lines.push(`export const allCsoundReferences: CsoundReference[] = [`);
    for (const varName of varNames) {
      lines.push(`  ...${varName},`);
    }
    lines.push(`]`);
    lines.push(``);

    lines.push(`export const csoundReferenceMap = new Map<string, CsoundReference>()`);
    lines.push(`allCsoundReferences.forEach(ref => {`);
    lines.push(`  csoundReferenceMap.set(ref.name, ref)`);
    lines.push(`})`);
    lines.push(``);

    lines.push(`export function getCsoundReference(name: string): CsoundReference | undefined {`);
    lines.push(`  return csoundReferenceMap.get(name)`);
    lines.push(`}`);
    lines.push(``);

    lines.push(`export function getCsoundReferencesByCategory(category: string): CsoundReference[] {`);
    lines.push(`  return allCsoundReferences.filter(ref => ref.category === category)`);
    lines.push(`}`);
    lines.push(``);

    lines.push(`export {`);
    for (const varName of varNames) {
      lines.push(`  ${varName},`);
    }
    lines.push(`}`);
    lines.push(``);

    return lines.join('\n');
  }

  writeCategoryFiles(categories: Map<string, CsoundReference[]>): void {
    if (!fs.existsSync(this.outputDir)) {
      fs.mkdirSync(this.outputDir, { recursive: true });
    }

    let fileCount = 0;

    for (const [category, references] of categories) {
      const fileName = this.sanitizeCategoryName(category);
      const filePath = path.join(this.outputDir, `${fileName}.ts`);
      const content = this.generateCategoryFile(category, references, fileName);

      fs.writeFileSync(filePath, content, 'utf-8');
      fileCount++;
      console.log(`Generated: ${fileName}.ts (${references.length} opcodes)`);
    }

    console.log(`\nGenerated ${fileCount} category files`);
  }

  writeMainFile(categories: Map<string, CsoundReference[]>): void {
    const filePath = path.join(this.outputDir, 'csoundReference.ts');
    const content = this.generateMainFile(categories);

    fs.writeFileSync(filePath, content, 'utf-8');
    console.log(`Generated: csoundReference.ts`);
  }

  copyTypes(): void {
    if (!fs.existsSync(this.outputDir)) {
      fs.mkdirSync(this.outputDir, { recursive: true });
    }

    const sourceTypes = path.join(__dirname, 'types.ts');
    const destTypes = path.join(this.outputDir, 'types.ts');

    if (fs.existsSync(sourceTypes)) {
      fs.copyFileSync(sourceTypes, destTypes);
      console.log(`Copied: types.ts`);
    }
  }

  generateAll(categories: Map<string, CsoundReference[]>): void {
    console.log(`\nGenerating TypeScript files...`);
    this.copyTypes();
    this.writeCategoryFiles(categories);
    this.writeMainFile(categories);
    console.log(`\nDone!`);
  }
}