/**
 *
 * Copyright 2014-2022 David Herron
 *
 * This file is part of AkashaCMS (http://akashacms.com/).
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

import path from 'node:path';
import { promises as fsp } from 'node:fs';
import util from 'node:util';
import * as data from './data.js';
import mahabhuta from 'mahabhuta';

import fastq from 'fastq';
import type { queueAsPromised } from "fastq";
import { Configuration } from './index.js';
import { RenderingContext } from '@akashacms/renderers';
import {
    DocumentsFileCache, Document
} from './cache/file-cache-sqlite.js';

//////////////////////////////////////////////////////////

/**
 * Where renderDocument is meant for a document on disk
 * and indexed by a DocumentsFileCache instance, this
 * function is meant for documents created from in-memory
 * data.  For instance, the tagged-content plugin generates
 * tag pages listing links to documents based on their tag.
 * These pages are instantiate out of data rather than
 * existing on-disk.
 *
 * Required data:
 *     * Blank page - with frontmatter including a "layout" template reference
 *     * File-name to use for virtual page, which also determines the rendered output file
 *     * Metadata derived from the frontmatter and filled with other stuff including the data to render into the page,  
 *
 * @param config 
 * @param docInfo 
 */
export async function renderVirtualDocument(
    config: Configuration,
    docInfo: {
        // The virtual pathname
        vpath: string;
        // The document to render as if it's
        // at that path
        document: string;
    }
) {


    const renderer = config.findRendererPath(
            docInfo.vpath
    );

    const rc = renderer.parseMetadata({
        fspath: docInfo.vpath,
        content: docInfo.document,
        metadata: {}
    });

    // Add necessary items to the metadata
    rc.metadata.config = config;
    rc.metadata.partial = (fname, metadata) => {
        return config.akasha.partial(config, fname, metadata);
    };
    rc.metadata.partialSync = (fname, metadata) => {
        return config.akasha.partialSync(config, fname, metadata);
    };
    rc.metadata.akasha = config.akasha;
    rc.metadata.plugin = config.plugin;

    // Render the primary content
    let docrendered = await renderer.render(rc);

    // If there is a layout template, render that
    // template passing the rendered primary content
    let layoutrendered;
    if (rc.metadata.layout) {
        const layouts = config.akasha
                .filecache.layoutsCache;
        const layoutInfo = await layouts.find(rc.metadata.layout);
        if (!layoutInfo) {
            throw new Error(`No layout found in ${util.inspect(config.layoutDirs)} for ${rc.metadata.layout} in file ${docInfo.vpath}`);
        }

        // Build the metadata for the layout rendering
        let layoutmetadata: any = {};
        for (var yprop in layoutInfo.metadata) {
            layoutmetadata[yprop] = layoutInfo.metadata[yprop];
        }
        for (var yprop in rc.metadata) {
            if (yprop !== 'layout') {
                layoutmetadata[yprop] = rc.metadata[yprop];
            }
        }

        // Make the first rendering available
        // in the metadata as "content" variable
        layoutmetadata.content = docrendered;

        const renderer = config.findRendererPath(
            rc.metadata.layout
        );

        if (!renderer) {
            throw new Error(`No renderer for ${layoutmetadata.layout} in file ${docInfo.vpath}`);;
        }

        const layoutContext = {
            fspath: layoutInfo.fspath,
            content: layoutInfo.docContent,
            body: layoutInfo.docBody,
            metadata: layoutmetadata
        };

        layoutrendered
        = await renderer.render(layoutContext);

    }

    // For HTML rendering, fun Mahabhuta functions
    const format = renderer.renderFormat(rc);
    const doMahabhuta = (format === 'HTML');

    if (doMahabhuta) {
        
        const mahametadata: any = {};
        for (var yprop in rc.metadata) {
            mahametadata[yprop] = rc.metadata[yprop];
        }
        mahametadata.content = docrendered;

        if (rc.metadata.config.mahabhutaConfig) {
            mahabhuta.config(rc.metadata.config.mahabhutaConfig);
        }

        layoutrendered = await mahabhuta.processAsync(
            typeof layoutrendered === 'string'
                    ? layoutrendered
                    : docrendered,
            mahametadata,
            config.mahafuncs
        );
    }

    // layoutrendered gets the final rendering
}

//////////////////////////////////////////////////////////

/**
 * The core part of rendering content using a renderer.
 * This function looks for the renderer, and if none is
 * found it simply returns.  It then does a little setup
 * to the metadata object, and calls the render function
 *
 * @param config - AkashaCMS Configuration
 * @param rc - RenderingContext for use with Renderers
 * @returns 
 */
export async function renderContent(
    config: Configuration,
    rc: RenderingContext
)
    // The return is a simple object
    // containing useful data
    : Promise<{
        rendererName?: string,
        format?: string,
        rendered: string
    }>
{
    // console.log(`renderContent `, rc);
    const renderer = config.findRendererPath(
        rc.fspath
    );
    if (!renderer) {
        return {
            rendererName: undefined,
            format: undefined,
            rendered: rc.body
        };
    }

    // Add necessary items to the metadata
    rc.metadata.config = config;
    rc.metadata.partial = (fname, metadata) => {
        return config.akasha.partial(config, fname, metadata);
    };
    rc.metadata.partialSync = (fname, metadata) => {
        return config.akasha.partialSync(config, fname, metadata);
    };
    rc.metadata.akasha = config.akasha;
    rc.metadata.plugin = config.plugin;

    // Render the primary content
    let docrendered = await renderer.render(rc);

    // console.log(`renderContent rendered=`, docrendered);
    return {
        rendererName: renderer.name,
        format: renderer.renderFormat(rc),
        rendered: docrendered
    };
}

/**
 * Render a document, accounting for the main content,
 * a layout template (if any), and Mahabhuta (if the content
 * output is HTML).  This also handles rendering other types
 * of content such as LESS CSS files.
 *
 * @param config 
 * @param docInfo 
 * @returns 
 */
export async function renderDocument(
    config: Configuration,
    docInfo
): Promise<string>
{
    const renderStart = new Date();

    // Render the main content

    const rc = <RenderingContext>{
        fspath: docInfo.vpath,
        content: docInfo.docContent,
        body: docInfo.docBody,
        metadata: docInfo.metadata
    };

    // console.log(`renderDocument context= ${rc.fspath}`)

    let docFormat;      // Knowing the format 
    let docRendered;
    try {
        const result = await renderContent(config, rc);
        docFormat = result.format;
        docRendered = result.rendered;
    } catch (err) {
        console.error(`Error rendering ${docInfo.vpath} ${(err.stack ? err.stack : err)}`);
        throw new Error(`Error rendering ${docInfo.vpath} ${(err.stack ? err.stack : err)}`);
    }
    // console.log(`renderDocument ${docInfo.vpath} rendered=`, docRendered);
    await data.report(docInfo.mountPoint, 
                      docInfo.vpath,
                      config.renderTo, 
                     "FIRST RENDER", renderStart);

    // Render the main content into a layout template,
    // if one is specified

    let layoutFormat;
    let layoutRendered;
    // console.log(`renderDocument layout ${docInfo?.metadata?.layout} docMetadata ${util.inspect(docInfo.docMetadata)} metadata ${util.inspect(docInfo.metadata)}`);
    if (docInfo?.metadata?.layout) {

        const layouts = config.akasha.filecache.layoutsCache;
        // await layouts.isReady();

        let found = await layouts.find(docInfo.metadata.layout);
        if (!found) {
            throw new Error(`No layout found in ${util.inspect(config.layoutDirs)} for ${docInfo.metadata.layout} in file ${docInfo.vpath}`);
        }

        const rcLayout = <RenderingContext>{
            fspath: docInfo.metadata.layout,
            content: found.docContent,
            body: found.docBody,
            metadata: {}
        };
        for (var yprop in found.metadata) {
            rcLayout.metadata[yprop] = found.metadata[yprop];
        }
        for (var yprop in docInfo.metadata) {
            if (yprop !== 'layout') {
                rcLayout.metadata[yprop] = docInfo.metadata[yprop];
            }
        }
        rcLayout.metadata.content = docRendered;

        try {
            const result
                = await renderContent(config, rcLayout);
            layoutFormat = result.format;
            layoutRendered = result.rendered;
        } catch (e) {
            let ee = new Error(`Error rendering ${docInfo.vpath} with ${docInfo.metadata.layout} ${e.stack ? e.stack : e}`);
            console.error(ee);
            throw ee;
        }
    } else {
        layoutFormat = docFormat;
        layoutRendered = docRendered;
    }

    // console.log(`renderDocument ${docInfo.vpath} after layout render format ${layoutFormat} `);

    const renderSecondRender = new Date();
    await data.report(docInfo.mountPoint,
                      docInfo.vpath, config.renderTo, 
                      "SECOND RENDER",
                      renderStart);

    
    // Next step is to run Mahabhuta on the rendered content
    // Of course, Mahabhuta is not appropriate for everything
    // because not everything is HTML

    const doMahabhuta = (layoutFormat === 'HTML');
    if (doMahabhuta) {

        try {

            const mahametadata: any = {};
            for (var yprop in docInfo.metadata) {
                mahametadata[yprop] = docInfo.metadata[yprop];
            }
            mahametadata.content = docRendered;

            if (docInfo.metadata.config.mahabhutaConfig) {
                mahabhuta.config(docInfo.metadata.config.mahabhutaConfig);
            }
            // console.log(`mahametadata`, mahametadata);
            layoutRendered = await mahabhuta.processAsync(
                layoutRendered, mahametadata,
                config.mahafuncs
            );

            // OLD docrendered = await this.maharun(layoutrendered, docdata, config.mahafuncs);
        } catch (e2) {
            let eee = new Error(`Error with Mahabhuta ${docInfo.vpath} with ${docInfo.metadata.layout} ${e2.stack ? e2.stack : e2}`);
            console.error(eee);
            throw eee;
        }

        await data.report(docInfo.mountPoint, 
                          docInfo.vpath,
                          config.renderTo, 
                          "MAHABHUTA", renderStart);

        const renderDest = path.join(
                    config.renderTo, docInfo.renderPath);
        await fsp.mkdir(path.dirname(renderDest), {
            recursive: true
        });
        await fsp.writeFile(renderDest,
                            layoutRendered, 'utf-8');

        // console.log(`RENDERED ${renderer.name} ${docInfo.path} ==> ${renderToFpath}`);
        const renderEndRendered = new Date();
        await data.report(
            docInfo.mountPoint, docInfo.vpath,
            config.renderTo,
            "RENDERED", renderStart);
        return `${layoutFormat} ${docInfo.vpath} ==> ${docInfo.renderPath} (${(renderEndRendered.valueOf() - renderStart.valueOf()) / 1000} seconds)\n${await data.data4file(docInfo.mountPoint, docInfo.vpath)}`;
    } else if (layoutFormat === 'CSS') {

        try {
            const renderToFpath = path.join(
                        config.renderTo, docInfo.renderPath);
            const renderToDir = path.dirname(renderToFpath);
            await fsp.mkdir(renderToDir, {
                        recursive: true
                    });
            await fsp.writeFile(renderToFpath, layoutRendered, 'utf8');
            const renderEndRendered = new Date();
            await data.report(
                docInfo.mountPoint, docInfo.vpath,
                config.renderTo,
                "RENDERED", renderStart);
            return `${layoutFormat} ${docInfo.vpath} ==> ${docInfo.renderPath} (${(renderEndRendered.valueOf() - renderStart.valueOf()) / 1000} seconds)\n${await data.data4file(docInfo.mountPoint, docInfo.vpath)}`;
        } catch(err) {
            console.error(`in RENDER CSS branch for ${docInfo.vpath} to ${docInfo.renderPath} error=${err.stack ? err.stack : err}`);
            throw new Error(`in RENDER CSS branch for ${docInfo.vpath} to ${docInfo.renderPath} error=${err.stack ? err.stack : err}`);
        }
    } else {

        try {
            const renderToFpath = path.join(
                        config.renderTo, docInfo.renderPath);
            const renderToDir = path.dirname(renderToFpath);
            await fsp.mkdir(renderToDir, {
                        recursive: true
                    });
            await fsp.copyFile(docInfo.fspath,
                               renderToFpath);
            // console.log(`COPIED ${docInfo.path} ==> ${renderToFpath}`);
            const renderEndCopied = new Date();
            return `COPY ${docInfo.vpath} ==> ${renderToFpath} (${(renderEndCopied.valueOf() - renderStart.valueOf()) / 1000} seconds)`;
        } catch(err) {
            console.error(`in copy branch for ${docInfo.vpath} to ${docInfo.renderPath} error=${err.stack ? err.stack : err}`);
            throw new Error(`in copy branch for ${docInfo.vpath} to ${docInfo.renderPath} error=${err.stack ? err.stack : err}`);
        }
    }
}

// export async function renderDocument2(config, docInfo) {
//     const renderStart = new Date();
//     const renderBaseMetadata = docInfo.baseMetadata;
//     // console.log(`renderDocument `, docInfo);

//     const renderer = config.findRendererPath(docInfo.vpath);
//     if (renderer) {

//         // console.log(`ABOUT TO RENDER ${renderer.name} ${docInfo.vpath} ==> ${renderToFpath}`);
//         try {


//             // Set up required metadata values

//             docInfo.metadata.config      = config;
//             docInfo.metadata.partial = (fname, metadata) => {
//                 return config.akasha.partial(config, fname, metadata);
//             }
//             docInfo.metadata.partialSync = (fname, metadata) => {
//                 return config.akasha.partialSync(config, fname, metadata);
//             }
//             docInfo.metadata.akasha = config.akasha;
//             docInfo.metadata.plugin = config.plugin;

//             // Render the document - output goes to "docrendered"

//             let docrendered;
//             try {
//                 const context = {
//                     fspath: docInfo.fspath,
//                     content: docInfo.docContent,
//                     body: docInfo.docBody,
//                     metadata: docInfo.metadata
//                 };
//                 // console.log({
//                 //     title: 'before DOCUMENT renderer.render',
//                 //     fspath: docInfo.fspath,
//                 //     content: docInfo.docContent,
//                 //     body: docInfo.docBody,
//                 //     metadata: docInfo.metadata,
//                 //     info: docInfo.info
//                 // });
//                 if (typeof context.content !== 'string'
//                  || typeof context.body !== 'string') {
//                     // console.warn(`render should fail for ${util.inspect(context)} `, docInfo);
//                 }
//                 docrendered = await renderer.render(context);
//             } catch (err) {
//                 console.error(`Error rendering ${docInfo.vpath} ${(err.stack ? err.stack : err)}`);
//                 throw new Error(`Error rendering ${docInfo.vpath} ${(err.stack ? err.stack : err)}`);
//             }
//             // console.log(docrendered);
//             await data.report(docInfo.mountPoint, docInfo.vpath, config.renderTo, 
//                                 "FIRST RENDER", renderStart);
            
//             // There may be a layout, which will be in metadata.layout
//             // If so, get the layout file
//             // Construct a new metadata -- and it's "content" is
//             // set from docrendered
//             // Then render the document into "layoutrendered"
//             // Otherwise cpy docrendered to layoutrendered

//             let layoutrendered;
//             if (docInfo.metadata.layout) {

//                 const layouts = config.akasha.filecache.layoutsCache;
//                 // await layouts.isReady();

//                 let found = await layouts.find(docInfo.metadata.layout);
//                 if (!found) {
//                     throw new Error(`No layout found in ${util.inspect(config.layoutDirs)} for ${docInfo.metadata.layout} in file ${docInfo.vpath}`);
//                 }

//                 let layoutmetadata: any = {};
//                 for (var yprop in found.metadata) {
//                     layoutmetadata[yprop] = found.metadata[yprop];
//                 }
//                 for (var yprop in docInfo.metadata) {
//                     if (yprop !== 'layout') {
//                         layoutmetadata[yprop] = docInfo.metadata[yprop];
//                     }
//                 }
//                 layoutmetadata.content = docrendered;

//                 const renderer = config.findRendererPath(docInfo.metadata.layout);

//                 if (!renderer) {
//                     throw new Error(`No renderer for ${layoutmetadata.layout} in file ${docInfo.vpath}`);;
//                 }

//                 const context = {
//                     fspath: found.fspath,
//                     content: found.docContent,
//                     body: found.docBody,
//                     metadata: layoutmetadata
//                 };

//                 if (typeof context.content !== 'string'
//                  || typeof context.body !== 'string') {
//                     throw new Error(`renderDocument LAYOUT RENDERING for ${docInfo.vpath} with layout ${docInfo.metadata.layout} has no context.content or context.body to which to render the content ${util.inspect(context)} ${util.inspect(found)}`);
//                 }

//                 // console.log(`renderDocument `, found);
//                 // console.log(`renderDocument `, layoutmetadata);

//                 try {
//                     layoutrendered
//                         = await renderer.render(context);
//                 } catch (e) {
//                     let ee = new Error(`Error rendering ${docInfo.vpath} with ${docInfo.metadata.layout} ${e.stack ? e.stack : e}`);
//                     console.error(ee);
//                     throw ee;
//                 }
//             } else {
//                 layoutrendered = docrendered;
//             }

//             const renderSecondRender = new Date();
//             await data.report(docInfo.mountPoint, docInfo.vpath, config.renderTo, 
//                                 "SECOND RENDER", renderStart);

//             // Next step is to run Mahabhuta on the rendered content
//             // Of course, Mahabhuta is not appropriate for everything
//             // because not everything is HTML

//             const format = renderer.renderFormat({ fspath: docInfo.fspath });
//             const doMahabhuta = (format === 'HTML') ? true :false;
//             if (doMahabhuta) {

//                 try {

//                     const mahametadata: any = {};
//                     for (var yprop in docInfo.metadata) {
//                         mahametadata[yprop] = docInfo.metadata[yprop];
//                     }
//                     mahametadata.content = docrendered;

//                     if (docInfo.metadata.config.mahabhutaConfig) {
//                         mahabhuta.config(docInfo.metadata.config.mahabhutaConfig);
//                     }
//                     // console.log(`mahametadata`, mahametadata);
//                     layoutrendered = await mahabhuta.processAsync(
//                         layoutrendered, mahametadata, config.mahafuncs
//                     );

//                     // OLD docrendered = await this.maharun(layoutrendered, docdata, config.mahafuncs);
//                 } catch (e2) {
//                     let eee = new Error(`Error with Mahabhuta ${docInfo.vpath} with ${docInfo.metadata.layout} ${e2.stack ? e2.stack : e2}`);
//                     console.error(eee);
//                     throw eee;
//                 }
//             }

//             await data.report(docInfo.mountPoint, docInfo.vpath, config.renderTo, 
//                 "MAHABHUTA", renderStart);

//             const renderDest = path.join(config.renderTo, docInfo.renderPath);
//             await fsp.mkdir(path.dirname(renderDest), { recursive: true });
//             await fsp.writeFile(renderDest, layoutrendered, 'utf-8');

//             // console.log(`RENDERED ${renderer.name} ${docInfo.path} ==> ${renderToFpath}`);
//             const renderEndRendered = new Date();
//             await data.report(
//                 docInfo.mountPoint, docInfo.vpath,
//                 config.renderTo,
//                 "RENDERED", renderStart);
//             return `${renderer.name} ${docInfo.vpath} ==> ${docInfo.renderPath} (${(renderEndRendered.valueOf() - renderStart.valueOf()) / 1000} seconds)\n${await data.data4file(docInfo.mountPoint, docInfo.vpath)}`;
//         } catch (err) {
//             console.error(`in renderer branch for ${docInfo.vpath} to ${docInfo.renderPath} error=${err.stack ? err.stack : err}`);
//             throw new Error(`in renderer branch for ${docInfo.vpath} to ${docInfo.renderPath} error=${err.stack ? err.stack : err}`);
//         }
//     } else {
//         // console.log(`COPYING ${docInfo.path} ==> ${renderToFpath}`);
//         try {
//             const renderToFpath = path.join(config.renderTo, docInfo.renderPath);
//             const renderToDir = path.dirname(renderToFpath);
//             await fsp.mkdir(renderToDir, { recursive: true });
//             await fsp.copyFile(docInfo.fspath, renderToFpath);
//             // console.log(`COPIED ${docInfo.path} ==> ${renderToFpath}`);
//             const renderEndCopied = new Date();
//             return `COPY ${docInfo.vpath} ==> ${renderToFpath} (${(renderEndCopied.valueOf() - renderStart.valueOf()) / 1000} seconds)`;
//         } catch(err) {
//             console.error(`in copy branch for ${docInfo.vpath} to ${docInfo.renderPath} error=${err.stack ? err.stack : err}`);
//             throw new Error(`in copy branch for ${docInfo.vpath} to ${docInfo.renderPath} error=${err.stack ? err.stack : err}`);
//         }
//     }
// }

/**
 * Render all the documents in a site, limiting
 * the number of simultaneous rendering tasks
 * to the number in config.concurrency.
 *
 * @param config
 * @returns
 */
export async function render(config) {

    const documents = <DocumentsFileCache>config.akasha.filecache.documentsCache;
    // await documents.isReady();
    // console.log('CALLING config.hookBeforeSiteRendered');
    await config.hookBeforeSiteRendered();
    
    // 1. Gather list of files from RenderFileCache
    const filez = await documents.paths();
    // console.log(`newerrender filez ${filez.length}`);

    // 2. Exclude any that we want to ignore
    const filez2 = [] as Array<{
        config: Configuration,
        info: Document
    }>;
    for (let entry of filez) {
        let include = true;
        // console.log(entry);
        let stats;
        try {
            stats = await fsp.stat(entry.fspath);
        } catch (err) { stats = undefined; }
        if (!entry) include = false;
        else if (!stats || stats.isDirectory()) include = false;
        // This should arise using an ignore clause
        // else if (path.basename(entry.vpath) === '.DS_Store') include = false;
        // else if (path.basename(entry.vpath) === '.placeholder') include = false;

        if (include) {
            // The queue is an array of tuples containing the
            // config object and the path string
            filez2.push({
                config: config,
                info: await documents.find(entry.vpath)
            });
        }
    }
    // console.log(`newerrender filez2 after ignore ${filez2.length}`);


    // 3. Make a fastq to process using renderDocument,
    //    pushing results to the results array

    // This sets up the queue processor
    // The concurrency setting lets us process documents
    // in parallel while limiting total impact.
    const queue: queueAsPromised<{
        config: Configuration,
        info: Document
    }> = fastq.promise(

        // This function is invoked for each entry in the
        // queue. It handles rendering the queue
        // The queue has config objects and path strings
        // which is exactly what's required by
        // renderDocument
        async function renderDocumentInQueue(entry)
            : Promise<{ result?: any; error?: any; }>
        {
            // console.log(`renderDocumentInQueue ${entry.info.vpath}`);
            try {
                let result = await renderDocument(
                    entry.config, entry.info
                );
                // console.log(`DONE renderDocumentInQueue ${entry.info.vpath}`, result);
                return { result };
            } catch (error) {
                // console.log(`ERROR renderDocumentInQueue ${entry.info.vpath}`, error.stack);
                return { error };
            }
        },
        config.concurrency);

    // queue.push returns a Promise that's fulfilled when
    // the task finishes.
    // Hence waitFor is an array of Promises.
    const waitFor = [];
    for (let entry of filez2) {
        waitFor.push(queue.push(entry));
    }

    // This automatically waits for all those
    // Promises to resolve, while making the results
    // array contain results.
    const results = [];
    for (let result of waitFor) {
        results.push(await result);
    }

    // 4. Invoke hookSiteRendered

    try {
        // console.log('Invoking hookSiteRendered');
        await config.hookSiteRendered();
    } catch (e) {
        console.error(e.stack);
        throw new Error(`hookSiteRendered failed because ${e}`);
    }

    // 5. return results
    return results;
};