import yaml from 'js-yaml';
import {
    isCSV,
    isFormData,
    isFormUrlEncoded,
    isGraphQL,
    isJSON,
    isPDF,
    isPlainObject,
    isText,
    isXML,
    isYAML,
} from './contentTypeChecks';
import { json2xml } from './json2xml';
import { stringifyOpenAPI } from './stringifyOpenAPI';
import { isValidServerHost } from './util/server';

export interface CodeSampleInput {
    method: string;
    url: {
        origin: string;
        path: string;
    };
    headers?: Record<string, string>;
    body?: any;
}

export interface CodeSampleGenerator {
    id: string;
    label: string;
    syntax: string;
    generate: (operation: CodeSampleInput) => string;
}

export const codeSampleGenerators: CodeSampleGenerator[] = [
    {
        id: 'http',
        label: 'HTTP',
        syntax: 'http',
        generate: ({ method, url: { origin, path }, headers = {}, body }: CodeSampleInput) => {
            if (body) {
                // if we had a body add a content length header
                const bodyContent = body ? stringifyOpenAPI(body) : '';
                // handle unicode chars with a text encoder
                const encoder = new TextEncoder();

                const bodyString = BodyGenerators.getHTTPBody(body, headers);

                if (bodyString) {
                    body = bodyString;
                }

                headers = {
                    ...headers,
                    'Content-Length': encoder.encode(bodyContent).length.toString(),
                };
            }

            if (!headers.hasOwnProperty('Accept')) {
                headers.Accept = '*/*';
            }

            const headerString = headers
                ? `${Object.entries(headers)
                      .map(([key, value]) =>
                          key.toLowerCase() !== 'host' ? `${key}: ${value}` : ''
                      )
                      .join('\n')}\n`
                : '';

            const bodyString = body ? `\n${body}` : '';

            // Only include Host header if origin is considered a valid server host
            const hasValidHost = isValidServerHost(origin);
            const hostLine = hasValidHost ? `Host: ${origin.replaceAll(/https?:\/\//g, '')}\n` : '';

            const httpRequest = `${method.toUpperCase()} ${decodeURI(path)} HTTP/1.1
${hostLine}${headerString}${bodyString}`;

            return httpRequest;
        },
    },
    {
        id: 'curl',
        label: 'cURL',
        syntax: 'bash',
        generate: ({ method, url: { origin, path }, headers, body }) => {
            const lines: string[] = ['curl -L'];

            if (method.toUpperCase() !== 'GET') {
                lines.push(`--request ${method.toUpperCase()}`);
            }

            lines.push(`--url '${origin}${path}'`);

            if (body) {
                const bodyContent = BodyGenerators.getCurlBody(body, headers);

                if (bodyContent) {
                    body = bodyContent.body;
                    headers = bodyContent.headers;
                }
            }

            if (headers && Object.keys(headers).length > 0) {
                Object.entries(headers).forEach(([key, value]) => {
                    lines.push(`--header '${key}: ${value}'`);
                });
            }

            if (body) {
                if (Array.isArray(body)) {
                    lines.push(...body);
                } else {
                    lines.push(body);
                }
            }

            return buildHeredoc(lines);
        },
    },
    {
        id: 'javascript',
        label: 'JavaScript',
        syntax: 'javascript',
        generate: ({ method, url: { origin, path }, headers, body }) => {
            let code = '';

            if (body) {
                const lines = BodyGenerators.getJavaScriptBody(body, headers);

                if (lines) {
                    // add the generated code to the top
                    code += lines.code;
                    body = lines.body;
                    headers = lines.headers;
                }
            }

            code += `const response = await fetch('${origin}${path}', {
    method: '${method.toUpperCase()}',\n`;

            if (headers && Object.keys(headers).length > 0) {
                code += indent(`headers: ${stringifyOpenAPI(headers, null, 2)},\n`, 4);
            }

            if (body) {
                code += indent(`body: ${body}\n`, 4);
            }

            code += '});\n\n';
            code += 'const data = await response.json();';

            return code;
        },
    },
    {
        id: 'python',
        label: 'Python',
        syntax: 'python',
        generate: ({ method, url: { origin, path }, headers, body }) => {
            const contentType = headers?.['Content-Type'];
            let code = `${isJSON(contentType) ? 'import json\n' : ''}import requests\n\n`;

            if (body) {
                const lines = BodyGenerators.getPythonBody(body, headers);

                // add the generated code to the top
                if (lines) {
                    code += lines.code;
                    body = lines.body;
                    headers = lines.headers;
                }
            }

            code += `response = requests.${method.toLowerCase()}(\n`;
            code += indent(`"${origin}${path}",\n`, 4);

            if (headers && Object.keys(headers).length > 0) {
                code += indent(`headers=${stringifyOpenAPI(headers)},\n`, 4);
            }

            if (body) {
                if (body === 'files') {
                    code += indent(`files=${body}\n`, 4);
                } else if (isJSON(contentType)) {
                    code += indent(`data=json.dumps(${body})\n`, 4);
                } else {
                    code += indent(`data=${body}\n`, 4);
                }
            }

            code += ')\n\n';
            code += 'data = response.json()';
            return code;
        },
    },
];

function indent(code: string, spaces: number) {
    const indent = ' '.repeat(spaces);
    return code
        .split('\n')
        .map((line) => (line ? indent + line : ''))
        .join('\n');
}

export function parseHostAndPath(url: string) {
    try {
        const urlObj = new URL(url);
        const path = urlObj.pathname || '/';
        return { host: urlObj.host, path };
    } catch (_e) {
        // If the URL was invalid do our best to parse the URL.
        // Check for the protocol part and pull it off to grab the host
        const splitted = url.split('//');
        const fullUrl = splitted[1] ? splitted[1] : url;

        // separate paths from the first element (host)
        const parts = fullUrl.split('/');
        // pull off the host (mutates)
        const host = parts.shift();
        // add a leading slash and join the paths again
        const path = `/${parts.join('/')}`;

        return { host, path };
    }
}

// Body Generators
const BodyGenerators = {
    getCurlBody(body: any, headers?: Record<string, string>) {
        if (!body || !headers) return undefined;

        // Copy headers to avoid mutating the original object
        const headersCopy = { ...headers };
        const contentType: string = headersCopy['Content-Type'] || '';

        if (isFormData(contentType)) {
            body = isPlainObject(body)
                ? Object.entries(body).map(([key, value]) => `--form '${key}=${String(value)}'`)
                : `--form 'file=@${body}'`;
        } else if (isFormUrlEncoded(contentType)) {
            body = isPlainObject(body)
                ? `--data '${Object.entries(body)
                      .map(([key, value]) => `${key}=${String(value)}`)
                      .join('&')}'`
                : String(body);
        } else if (isText(contentType)) {
            body = `--data '${String(body).replace(/"/g, '')}'`;
        } else if (isXML(contentType)) {
            // Convert to XML and ensure proper formatting
            body = `--data-binary $'${convertBodyToXML(body)}'`;
        } else if (isCSV(contentType)) {
            // We use --data-binary to avoid cURL converting newlines to \r\n
            body = `--data-binary $'${stringifyOpenAPI(body).replace(/"/g, '').replace(/\\n/g, '\n')}'`;
        } else if (isGraphQL(contentType)) {
            body = `--data '${stringifyOpenAPI(body)}'`;
            // Set Content-Type to application/json for GraphQL, recommended by GraphQL spec
            headersCopy['Content-Type'] = 'application/json';
        } else if (isPDF(contentType)) {
            // We use --data-binary to avoid cURL converting newlines to \r\n
            body = `--data-binary '@${String(body)}'`;
        } else if (isYAML(contentType)) {
            body = `--data-binary $'${yaml.dump(body).replace(/'/g, '').replace(/\\n/g, '\n')}'`;
        } else {
            // For JSON, check if it contains single quotes, if so, use heredoc to avoid single quote issues
            const jsonString = stringifyOpenAPI(body, null, 2).replace(/\\n/g, '\n');
            if (jsonString.includes("'")) {
                // Use heredoc format: return array with --data @- <<'EOF', JSON lines, and EOF
                const jsonLines = jsonString.split('\n');
                body = ["--data @- <<'EOF'", ...jsonLines, 'EOF'];
            } else {
                body = `--data '${jsonString}'`;
            }
        }

        return {
            body,
            headers: headersCopy,
        };
    },
    getJavaScriptBody: (body: any, headers?: Record<string, string>) => {
        if (!body || !headers) return;

        let code = '';

        // Copy headers to avoid mutating the original object
        const headersCopy = { ...headers };
        const contentType: string = headersCopy['Content-Type'] || '';

        // Use FormData for file uploads
        if (isFormData(contentType)) {
            code += 'const formData = new FormData();\n\n';
            if (isPlainObject(body)) {
                Object.entries(body).forEach(([key, value]) => {
                    code += `formData.append("${key}", "${String(value)}");\n`;
                });
            } else if (typeof body === 'string') {
                code += `formData.append("file", "${body}");\n`;
            }
            code += '\n';
            body = 'formData';
        } else if (isFormUrlEncoded(contentType)) {
            // Use URLSearchParams for form-urlencoded data
            code += 'const params = new URLSearchParams();\n\n';
            if (isPlainObject(body)) {
                Object.entries(body).forEach(([key, value]) => {
                    code += `params.append("${key}", "${String(value)}");\n`;
                });
            }
            code += '\n';
            body = 'params.toString()';
        } else if (isGraphQL(contentType)) {
            if (isPlainObject(body)) {
                Object.entries(body).forEach(([key, value]) => {
                    code += `const ${key} = \`\n${indent(String(value), 4)}\`;\n\n`;
                });
                body = `JSON.stringify({ ${Object.keys(body).join(', ')} })`;
                // Set Content-Type to application/json for GraphQL, recommended by GraphQL spec
                headersCopy['Content-Type'] = 'application/json';
            } else {
                code += `const query = \`\n${indent(String(body), 4)}\`;\n\n`;
                body = 'JSON.stringify(query)';
            }
        } else if (isCSV(contentType)) {
            code += 'const csv = `\n';
            code += indent(String(body), 4);
            code += '`;\n\n';
            body = 'csv';
        } else if (isPDF(contentType)) {
            // Use FormData to upload PDF files
            code += 'const formData = new FormData();\n\n';
            code += `formData.append("file", "${body}");\n\n`;
            body = 'formData';
        } else if (isXML(contentType)) {
            code += 'const xml = `\n';

            // Convert JSON to XML if needed
            code += indent(convertBodyToXML(body), 4);
            code += '`;\n\n';
            body = 'xml';
        } else if (isYAML(contentType)) {
            code += `const yamlBody = \`\n${indent(yaml.dump(body), 4)}\`;\n\n`;
            body = 'yamlBody';
        } else if (isText(contentType)) {
            body = stringifyOpenAPI(body, null, 2);
        } else {
            body = `JSON.stringify(${stringifyOpenAPI(body, null, 2)})`;
        }

        return { body, code, headers: headersCopy };
    },
    getPythonBody: (body: any, headers?: Record<string, string>) => {
        if (!body || !headers) return;
        let code = '';
        const contentType: string = headers['Content-Type'] || '';

        if (isFormData(contentType)) {
            code += 'files = {\n';
            if (isPlainObject(body)) {
                Object.entries(body).forEach(([key, value]) => {
                    code += `${indent(`"${key}": "${String(value)}",`, 4)}\n`;
                });
            }
            code += '}\n\n';
            body = 'files';
        } else if (isPDF(contentType)) {
            code += 'files = {\n';
            code += `${indent(`"file": "${body}",`, 4)}\n`;
            code += '}\n\n';
            body = 'files';
        } else if (isXML(contentType)) {
            // Convert JSON to XML if needed
            body = JSON.stringify(convertBodyToXML(body));
        } else if (isYAML(contentType)) {
            code += `yamlBody = \"\"\"\n${indent(yaml.dump(body), 4)}\"\"\"\n\n`;
            body = 'yamlBody';
        } else {
            body = stringifyOpenAPI(
                body,
                (_key, value) => {
                    switch (value) {
                        case true:
                            return '$$__TRUE__$$';
                        case false:
                            return '$$__FALSE__$$';
                        case null:
                            return '$$__NULL__$$';
                        default:
                            return value;
                    }
                },
                2
            )
                .replaceAll('"$$__TRUE__$$"', 'True')
                .replaceAll('"$$__FALSE__$$"', 'False')
                .replaceAll('"$$__NULL__$$"', 'None');
        }

        return { body, code, headers };
    },
    getHTTPBody: (body: any, headers?: Record<string, string>) => {
        if (!body || !headers) return undefined;

        const contentType: string = headers['Content-Type'] || '';

        const typeHandlers = {
            pdf: () => `${stringifyOpenAPI(body, null, 2)}`,
            formUrlEncoded: () => {
                const encoded = isPlainObject(body)
                    ? Object.entries(body)
                          .map(([key, value]) => `${key}=${stringifyOpenAPI(value)}`)
                          .join('&')
                    : stringifyOpenAPI(body);
                return `"${encoded.replace(/"/g, "'")}"`;
            },
            text: () => `"${String(body)}"`,
            xml: () => {
                // Convert JSON to XML if needed
                return `"${convertBodyToXML(body)}"`;
            },
            yaml: () => `"${yaml.dump(body).replace(/"/g, '\\"')}"`,
            csv: () => `"${stringifyOpenAPI(body).replace(/"/g, '')}"`,
            default: () => `${stringifyOpenAPI(body, null, 2)}`,
        };

        if (isPDF(contentType)) return typeHandlers.pdf();
        if (isFormUrlEncoded(contentType)) return typeHandlers.formUrlEncoded();
        if (isText(contentType)) return typeHandlers.text();
        if (isXML(contentType)) return typeHandlers.xml();
        if (isYAML(contentType)) return typeHandlers.yaml();
        if (isCSV(contentType)) return typeHandlers.csv();

        return typeHandlers.default();
    },
};

/**
 * Converts a body to XML format
 */
function convertBodyToXML(body: any): string {
    // If body is already a string and looks like XML, return it as is
    if (typeof body === 'string' && body.trim().startsWith('<')) {
        return body;
    }

    // If body is not an object, try to parse it as JSON
    if (typeof body !== 'object' || body === null) {
        try {
            body = JSON.parse(body);
        } catch {
            // If parsing fails, return the original body
            return body;
        }
    }

    return json2xml(body).replace(/"/g, '').replace(/\\n/g, '\n').replace(/\\t/g, '\t');
}

/**
 * Builds a heredoc string from an array of lines
 */
function buildHeredoc(lines: string[]): string {
    const separator = ' \\\n';
    let result = '';
    let inHeredoc = false;

    for (let i = 0; i < lines.length; i++) {
        const line = lines[i];
        if (!line) continue;

        const isHeredocStart = line.includes("<<'EOF'");
        const isHeredocEnd = inHeredoc && line === 'EOF';

        if (isHeredocStart) {
            inHeredoc = true;
            // Heredoc start: indent with backslash continuation from previous line, then newline
            result += `${i > 0 ? indent(line, 2) : line}\n`;
        } else if (isHeredocEnd) {
            inHeredoc = false;
            // EOF: no indent, no backslash, no separator
            result += line;
        } else if (inHeredoc) {
            // Inside heredoc: indent JSON lines, no backslash, newline
            result += `${indent(line, 2)}\n`;
        } else {
            // Normal line: indent and add separator (backslash) if not last line
            result += `${i > 0 ? indent(line, 2) : line}${i < lines.length - 1 ? separator : ''}`;
        }
    }
    return result;
}