import * as sass from "sass"
import {
  escapeHtmlAttr,
  expandTilde,
  firstFound,
  generateRandomId,
  getCleanPath,
  getHref,
  slugifyString,
  writeFile,
} from "./util/index.js"
import { glob } from "glob"
import fs from "fs/promises"
import handlebars from "handlebars"
import { marked } from "marked"
import markedCodePreview from "marked-code-preview"
import matter from "gray-matter"
import { optimize } from "svgo"
import sharp from "sharp"
import path from "path"
import { minify } from "html-minifier-terser"
import favicons from "favicons"
import _ from "lodash-es"

const templateCache = new Map()
const partialCache = new Map()
const registeredPartials = new Set()

export function clearTemplateCache() {
  templateCache.clear()
  partialCache.clear()
  registeredPartials.clear()
}

async function loadPartials(partialDirs) {
  if (!partialDirs || partialDirs.length === 0) {
    return []
  }

  const loadedPaths = []

  for (const dir of partialDirs) {
    const expandedDir = expandTilde(dir)
    const pattern = path.join(expandedDir, "*.hbs")

    let files
    try {
      files = await glob(pattern)
    } catch {
      continue
    }

    for (const filePath of files) {
      const fileName = path.basename(filePath, ".hbs")
      // Remove leading underscore if present (e.g., _pagination -> pagination)
      const partialName = fileName.startsWith("_") ? fileName.slice(1) : fileName

      if (registeredPartials.has(partialName)) {
        continue
      }

      if (!partialCache.has(filePath)) {
        const content = await fs.readFile(filePath, "utf8")
        partialCache.set(filePath, { name: partialName, content })
      }

      const partial = partialCache.get(filePath)
      handlebars.registerPartial(partial.name, partial.content)
      registeredPartials.add(partialName)
      loadedPaths.push(filePath)
    }
  }

  return loadedPaths
}

function createMarkdownRenderer(meta) {
  return marked
    .use({ gfm: true })
    .use(markedCodePreview)
    .use({
      renderer: {
        image({ href, title, text }) {
          const attrs = [`alt="${escapeHtmlAttr(text)}"`]

          const foundSrcSet = meta.resources.images?.[slugifyString(href)]

          if (foundSrcSet && foundSrcSet.detail.srcSet?.length > 0) {
            const srcSetString = foundSrcSet.detail.srcSet
              .map(src => src.join(" "))
              .join(", ")
            const defaultSrc = foundSrcSet.detail.srcSet[0][0]
            attrs.push(`src="${escapeHtmlAttr(defaultSrc)}"`)
            attrs.push(`srcset="${escapeHtmlAttr(srcSetString)}"`)
            attrs.push("sizes=\"(min-width: 800px) 40vw, 100vw\"")
            attrs.push(
              `style="aspect-ratio: ${escapeHtmlAttr(foundSrcSet.detail.aspectRatio)}"`,
            )
          } else {
            attrs.push(`src="${escapeHtmlAttr(href)}"`)
          }

          if (title) {
            attrs.push(`title="${escapeHtmlAttr(title)}"`)
          }

          return `<img ${attrs.join(" ")} >`
        },
      },
    })
}
async function findTemplatePath(templateDirs, templateName) {
  const templatePath = await firstFound(templateDirs, `${templateName}.hbs`)
  if (!templatePath) throw new Error(`Template not found: ${templateName}`)
  return templatePath
}

async function getTemplate(templatePath) {
  if (!templateCache.has(templatePath)) {
    const templateContent = await fs.readFile(templatePath, "utf8")
    templateCache.set(templatePath, {
      path: templatePath,
      renderer: handlebars.compile(templateContent),
    })
  }
  return templateCache.get(templatePath)
}

export async function renderTemplate({ config, meta }) {
  const templateName = config.template || config.defaultTemplate
  const templatePath =
    config.filePath ||
    (await findTemplatePath(config.templateDirs, templateName))
  const fileOutputPath = config.fileOutputPath
  const href = getHref(fileOutputPath, meta)

  // Load partials from configured directories
  const partialPaths = await loadPartials(config.partialDirs)

  const template = await getTemplate(templatePath)
  const html = template.renderer({
    ...meta,
    href,
    ...config,
  })
  if (config.writeOut) {
    const minifiedHtml = await minify(html, {
      collapseWhitespace: true,
      removeComments: true,
      removeRedundantAttributes: true,
      removeEmptyAttributes: true,
      minifyCSS: true,
      minifyJS: true,
    })

    await writeFile(fileOutputPath, minifiedHtml)
    return {
      detail: { html },
      deps: {
        paths: [template.path, ...partialPaths],
      },
      paths: [fileOutputPath],
      ref: slugifyString(href),
    }
  }

  return {
    detail: { html },
    deps: {
      paths: [template.path, ...partialPaths],
    },
    ref: slugifyString(href),
  }
}
export async function renderMarkdownToHtml({ config, meta }) {
  const filePath = config.filePath
  const fileOutputPath = config.fileOutputPath
  const content = await fs.readFile(filePath, "utf8")
  const { data, content: markdown } = matter(content)
  const href = getHref(fileOutputPath, meta)

  const renderer = createMarkdownRenderer(meta)
  const html = renderer(markdown)
  const detail = { ...data, href, content: html, fileOutputPath }

  return {
    detail,
    ref: slugifyString(filePath),
  }
}
export async function renderMarkdownWithTemplate({ config, meta }) {
  const filePath = config.filePath
  const fileOutputPath = config.fileOutputPath
  const content = await fs.readFile(filePath, "utf8")
  const { data, content: markdown } = matter(content)
  const templateName = data.template || config.defaultTemplate
  const href = getHref(fileOutputPath, meta)

  if (!templateCache.has(templateName)) {
    const templatePath = await firstFound(
      config.templateDirs,
      `${templateName}.hbs`,
    )
    if (!templatePath) throw new Error(`Template not found: ${templateName}`)
    const templateContent = await fs.readFile(templatePath, "utf8")
    templateCache.set(templateName, {
      path: templatePath,
      renderer: handlebars.compile(templateContent),
    })
  }
  const template = templateCache.get(templateName)
  const renderer = createMarkdownRenderer(meta)
  const html = template.renderer({
    ...data,
    ...meta,
    href,
    content: renderer(markdown),
  })
  const minifiedHtml = await minify(html, {
    collapseWhitespace: true,
    removeComments: true,
    removeRedundantAttributes: true,
    removeEmptyAttributes: true,
    minifyCSS: true,
    minifyJS: true,
  })

  await writeFile(fileOutputPath, minifiedHtml)

  return {
    detail: { ...data, href },
    paths: [fileOutputPath],
    deps: {
      paths: [template.path],
    },
    ref: slugifyString(fileOutputPath),
  }
}

export async function compileSass({ config, meta }) {
  const filePath = config.filePath
  const fileOutputPath = config.fileOutputPath
  const result = await sass.compileAsync(filePath, { style: "compressed" })
  await writeFile(fileOutputPath, result.css)
  return {
    paths: [fileOutputPath],
    ref: slugifyString(fileOutputPath),
    detail: {
      href: fileOutputPath.replace(meta.opts.outDir, "/"),
    },
    deps: {
      paths: [...result.loadedUrls.map(item => item.pathname)],
    },
  }
}

export async function optimiseSvg({ config }) {
  const filePath = config.filePath
  const fileOutputPath = config.fileOutputPath
  const svgString = await fs.readFile(filePath, "utf8")
  const result = optimize(svgString, {
    plugins: ["preset-default"],
  })
  await writeFile(fileOutputPath, result.data)
  return {
    paths: [fileOutputPath],
    ref: slugifyString(fileOutputPath),
  }
}

export async function copy({ config }) {
  const filePath = config.filePath
  const fileOutputPath = config.fileOutputPath
  await fs.mkdir(config.fileOutputDir, { recursive: true })
  await fs.copyFile(filePath, fileOutputPath)
  return {
    paths: [fileOutputPath],
    ref: slugifyString(fileOutputPath),
  }
}

export async function imageToWebP({ meta, config }) {
  const filePath = config.filePath
  const fileOutputDir = config.fileOutputDir
  const sourceExtension = path.extname(filePath)
  const outputExtension = config.outputFileExtension
  const base = path.basename(filePath, sourceExtension)
  await fs.mkdir(fileOutputDir, { recursive: true })

  const original = sharp(filePath)
  const metadata = await original.metadata()
  const { width, height } = metadata

  if (!width || !height) {
    throw new Error("Could not determine image dimensions")
  }

  const aspectRatio = width / height
  const name = config.uniqueFilenames ? `${base}-${generateRandomId()}` : base
  const imageSizes = Array.isArray(config.imageSizes) ? config.imageSizes : []
  if (imageSizes.length === 0) {
    throw new Error(`imageToWebP: imageSizes must be a non-empty array for ${filePath}`)
  }
  const outputFiles = []
  const srcSet = await Promise.all(
    imageSizes.map(async size => {
      const sizeStr = typeof size === "string" ? size : String(size)
      const sizeNum = parseInt(sizeStr.replace("w", ""), 10)
      const outputFile = path.join(
        fileOutputDir,
        `${name}-${sizeNum}${outputExtension}`,
      )

      await original
        .clone()
        .resize(sizeNum)
        .webp({ quality: config.quality })
        .toFile(outputFile)

      outputFiles.push(outputFile)
      return [getCleanPath(outputFile, meta), size]
    }),
  )

  const imageRef = slugifyString(getCleanPath(path.join(filePath), meta))

  return {
    paths: outputFiles,
    detail: { srcSet, aspectRatio },
    ref: imageRef,
  }
}

export async function generateFavicons({ meta, config }) {
  const filePath = config.filePath
  const fileOutputDir = config.fileOutputDir
  // Configuration for favicons package
  const configuration = {
    path: getCleanPath(fileOutputDir, meta), // Path for overriding default icons path
    appName: meta.opts.site?.name || "Website",
    appShortName: meta.opts.site?.shortName || "Site",
    appDescription: meta.opts.site?.description || "",
    developerName: meta.opts.site?.author || "",
    developerURL: meta.opts.site?.url || "",
    dir: "auto",
    lang: meta.opts.site?.language || "en-US",
    background: meta.opts.site?.backgroundColor || "#ffffff",
    theme_color: meta.opts.site?.themeColor || "#ffffff",
    appleStatusBarStyle: "black-translucent",
    display: "standalone",
    orientation: "any",
    scope: "/",
    start_url: "/",
    version: "1.0",
    logging: false,
    pixel_art: false,
    loadManifestWithCredentials: false,
    manifestMaskable: false,
    icons: {
      android: true,
      appleIcon: true,
      appleStartup: true,
      favicons: true,
      windows: true,
      yandex: true,
    },
  }
  try {
    const response = await favicons(filePath, configuration)

    // Write all generated images to disk
    await Promise.all(
      response.images.map(async image => {
        const outputPath = path.join(fileOutputDir, image.name)
        await writeFile(outputPath, image.contents)
      }),
    )

    // Write all generated files (manifests, etc.) to disk
    await Promise.all(
      response.files.map(async file => {
        const outputPath = path.join(fileOutputDir, file.name)
        await writeFile(outputPath, file.contents)
      }),
    )

    // Combine HTML meta tags
    const htmlMeta = response.html.join("\n    ")
    return {
      detail: {
        htmlMeta,
      },
      paths: [
        ...response.images.map(img => path.join(fileOutputDir, img.name)),
        ...response.files.map(file => path.join(fileOutputDir, file.name)),
      ],
      ref: config.name,
    }
  } catch (error) {
    throw new Error(`Failed to generate favicons: ${error.message}`)
  }
}

export async function generateTaxonomy({ config }) {
  if (!Array.isArray(config.inputs)) {
    return {
      detail: config.indexOn ? {} : [],
      ref: config.name,
    }
  }
  const allValues = config.inputs.reduce((values, curr) => {
    const items = curr[config.indexOn] || []
    items.forEach(v => values.add(v))
    return values
  }, new Set())
  const orderBy = config.orderBy || "date"
  const sortedInputs = config.sortAscending
    ? _.sortBy(config.inputs, orderBy)
    : _.sortBy(config.inputs, orderBy).reverse()
  const taxonomy = config.indexOn
    ? [...allValues.values()].reduce((groups, currentGroup) => {
      const grouped = {
        ...groups,
        [currentGroup]: sortedInputs
          .filter(item => item[config.indexOn].includes(currentGroup))
          .map(item => {
            const entry = config.properties
              ? config.properties.reduce(
                (ent, prop) => ({ ...ent, [prop]: item[prop] }),
                {},
              )
              : item
            return entry
          }),
      }
      return grouped
    }, {})
    : sortedInputs.map(item => {
      const entry = config.properties
        ? config.properties.reduce(
          (ent, prop) => ({ ...ent, [prop]: item[prop] }),
          {},
        )
        : item
      return entry
    })
  return {
    detail: taxonomy,
    ref: config.name,
  }
}