lamium/template/template.go

// Package template implements HTML page generation functions from a default
// or custom theme.
package template

import (
	"embed"
	"html"
	"os"
	"path/filepath"
	"regexp"
	"slices"
	"strconv"
	"strings"

	image "lamium/image"
	util "lamium/util"
)

type (
	// A Set is a collection of images. The Set type contains properties
	// about the collection such as the source directory for the images
	// and how to display them.
	//
	// JSON tags are included for config file marshalling.
	Set struct {
		Name           string `json:"name"`
		ImageDir       string `json:"imageDir"`
		IndexHTML      string `json:"indexHTML"`
		Title          string `json:"title"`
		SortOrder      string `json:"sortOrder"`
		CSSClassIframe string `json:"cssClassIframe"`
		CSSClassLink   string `json:"cssClassLink"`
		CSSClassThumb  string `json:"cssClassThumb"`
		LightboxOn     bool   `json:"lightboxOn"`
		LinkType       string `json:"linkType"`
		ThumbDir       string `json:"thumbDir"`
		ThumbWidth     int    `json:"thumbWidth"`
		ThumbHeight    int    `json:"thumbHeight"`
		ThumbPct       int    `json:"thumbPercent"`
		ThumbClip      string `json:"thumbClip"`
		ThumbUnifyMode string `json:"thumbUnifyMode"`
	}
)

var (
	// File extensions for captions.
	CaptionExt = map[string]string{
		"html": ".html",
		"txt":  ".txt",
	}

	// Supported HTML markup tags.
	MarkupHTML = map[string]string{
		"&lt;b&gt;":           "<b>",
		"&lt;/b&gt;":          "</b>",
		"&lt;blockquote&gt;":  "<blockquote>",
		"&lt;/blockquote&gt;": "</blockquote>",
		"&lt;br&gt;":          "<br>",
		"&lt;code&gt;":        "<code>",
		"&lt;/code&gt;":       "</code>",
		"&lt;del&gt;":         "<del>",
		"&lt;/del&gt;":        "</del>",
		"&lt;dd&gt;":          "<dd>",
		"&lt;/dd&gt;":         "</dd>",
		"&lt;dl&gt;":          "<dl>",
		"&lt;/dl&gt;":         "</dl>",
		"&lt;dt&gt;":          "<dt>",
		"&lt;/dt&gt;":         "</dt>",
		"&lt;em&gt;":          "<em>",
		"&lt;/em&gt;":         "</em>",
		"&lt;h1&gt;":          "<h1>",
		"&lt;/h1&gt;":         "</h1>",
		"&lt;h2&gt;":          "<h2>",
		"&lt;/h2&gt;":         "</h2>",
		"&lt;h3&gt;":          "<h3>",
		"&lt;/h3&gt;":         "</h3>",
		"&lt;i&gt;":           "<i>",
		"&lt;/i&gt;":          "</i>",
		"&lt;ol&gt;":          "<ol>",
		"&lt;/ol&gt;":         "</ol>",
		"&lt;p&gt;":           "<p>",
		"&lt;/p&gt;":          "</p>",
		"&lt;strong&gt;":      "<strong>",
		"&lt;/strong&gt;":     "</strong>",
		"&lt;s&gt;":           "<s>",
		"&lt;/s&gt;":          "</s>",
		"&lt;u&gt;":           "<u>",
		"&lt;/u&gt;":          "</u>",
		"&lt;ul&gt;":          "<ul>",
		"&lt;/ul&gt;":         "</ul>",
	}

	// Supported markup syntax regexp for text files and the HTML tag
	// translations.
	MarkupTxt = []map[string]string{
		{`^\*\*`: "<strong>"},
		{`\*\*$`: "</strong>"},
		{`\*\*\n`: "</strong>\n"},
		{`\t\*\*`: "\t<strong>"},
		{`\*\*\t`: "</strong>\t"},
		{`[[:space:]]\*\*`: " <strong>"},
		{`\*\*[[:space:]]`: "</strong> "},
		{`^\*`: "<em>"},
		{`\*$`: "</em>"},
		{`\*\n`: "</em>\n"},
		{`\t\*`: "\t<em>"},
		{`\*\t`: "</em>\t"},
		{`[[:space:]]\*`: " <em>"},
		{`\*[[:space:]]`: "</em> "},
		{`^__`: "<u>"},
		{`__$`: "</u>"},
		{`__\n`: "</u>\n"},
		{`\t__`: "\t<u>"},
		{`__\t`: "</u>\t"},
		{`[[:space:]]__`: " <u>"},
		{`__[[:space:]]`: "</u> "},
		{`^\~\~`: "<s>"},
		{`\~\~$`: "</s>"},
		{`\~\~\n`: "</s>\n"},
		{`\t\~\~`: "\t<s>"},
		{`\~\~\t`: "</s>\t"},
		{`[[:space:]]\~\~`: " <s>"},
		{`\~\~[[:space:]]`: "</s> "},
		{`\[url=`: `<a href="`},
		{`\[\/url\]`: "</a>"},
		{`\[h1\]`: "<h1>"},
		{`\[\/h1\]`: "</h1>"},
		{`\[h2\]`: "<h2>"},
		{`\[\/h2\]`: "</h2>"},
		{`\[h3\]`: "<h3>"},
		{`\[\/h3\]`: "</h3>"},
		{`\]`: `">`},
		{"\n\n": "</p>\n<p>"},
		{"  \n": "<br>"},
	}

	// Template variables used in partials.
	PartVar = map[string]string{
		"id":          "{{ id }}",
		"iframeClass": "{{ iframe_class }}",
		"link":        "{{ link }}",
		"linkClass":   "{{ link_class }}",
		"navNext":     "{{ nav_next }}",
		"navPrev":     "{{ nav_prev }}",
		"navTop":      "{{ nav_top }}",
		"thumb":       "{{ thumb }}",
		"thumbClass":  "{{ thumb_class }}",
		"set":         "[set]",
	}

	// HTML partials that are inserted into templates.
	PartHTML = map[string]string{
		"img": `<a class="` + PartVar["linkClass"] + `" href="` +
			PartVar["link"] + `"><img class="` + PartVar["thumbClass"] +
			`" src="` + PartVar["thumb"] + `"></a>` + "\n",
		"lightbox": `<iframe class="` + PartVar["iframeClass"] + `" id="` +
			PartVar["id"] + `" src="` + PartVar["link"] + `"></iframe>
			<nav class="nav">
			<a class="prev" href="` + PartVar["navPrev"] + `">&larr;</a>
			<a class="close" href="#">&#9747;</a>
			<a class="next" href="` + PartVar["navNext"] + `">&rarr;</a>` +
			`</nav>` + "\n",
		"nav": `<a class="link" href="` + PartVar["navPrev"] + `">&larr;</a>
    		<a class="link" href="` + PartVar["navTop"] + `">&uarr;</a>
    		<a class="link" href="` + PartVar["navNext"] + `">&rarr;</a>`,
	}

	// Sample theme directory path relative to the album root.
	//
	// If changing this value, the go:embed directive for the ThemeFile variable
	// also needs to be updated, to store the theme files at compile time.
	SampleThemeDir = "themes/nettle"

	// Theme template filenames.
	Theme = struct {
		Index       string `json:"index"`
		Image       string `json:"_image"`
		Set         string `json:"_set"`
		Sets        string `json:"_sets"`
		Text        string `json:"_text"`
		AlbumCSS    string `json:"albumCSS"`
		LightboxCSS string `json:"lightboxCSS"`
	}{
		Index:       "index.html",
		Image:       "_image.html",
		Set:         "_set.html",
		Sets:        "_sets.html",
		Text:        "_text.html",
		AlbumCSS:    "album.css",
		LightboxCSS: "lightbox.css",
	}

	// Template variables used in theme files.
	ThemeVar = map[string]map[string]string{
		Theme.Index: {
			"content": "{{ index_content }}",
			"relPath": "{{ index_relpath }}",
			"title":   "{{ index_title }}",
		},
		Theme.Image: {
			"caption": "{{ image_caption }}",
			"path":    "{{ image_path }}",
			"title":   "{{ image_title }}",
			"nav":     "{{ nav }}",
		},
		Theme.Set: {
			"content":  "{{ set }}",
			"desc":     "{{ set_desc }}",
			"lightbox": "{{ set_lightbox }}",
			"name":     "{{ set_name }}",
			"title":    "{{ set_title }}",
		},
		Theme.Sets: {
			"content":  "{{ set_[set] }}",
			"desc":     "{{ set_[set]_desc }}",
			"lightbox": "{{ set_[set]_lightbox }}",
			"name":     "{{ set_[set]_name }}",
			"title":    "{{ set_[set]_title }}",
		},
		Theme.Text: {
			"content": "{{ text_content }}",
			"title":   "{{ text_title }}",
		},
	}
)

// Compile-time theme embed directive.
// Ensure this path corresponds with SampleThemeDir.
//
//go:embed themes/nettle/*
var ThemeFile embed.FS

// GetHTMLFilename returns the value of path with the base filename reset to
// Theme.Index if path contains a conflicting or invalid filename. Otherwise,
// returns a copy of path.
func GetHTMLFilename(path string) string {
	str := filepath.Join(filepath.Dir(path), Theme.Index)
	if util.ReplaceExt(filepath.Base(path), "") != "" && filepath.Ext(path) ==
		filepath.Ext(Theme.Index) {
		str = path
	}
	return str
}

// CheckDup returns a renamed path if a file by the same name already
// exists in the same srcDir and is not a caption text file. If the file path
// does not already exist, returns the original path.
func CheckDup(path, srcDir, ext string) string {
	files := util.GetFileList(srcDir, "name", false)
	name := util.ReplaceExt(filepath.Base(path), "")
	num := strconv.Itoa(len(files) + 1)
	newPath := filepath.Join(filepath.Dir(path), name+num+ext)
	for _, file := range files {
		if util.ReplaceExt(filepath.Base(file), "") == name &&
			filepath.Base(file) != name+CaptionExt["txt"] {
			return newPath
		}
	}
	return path
}

// GenTheme outputs the theme files to the album directory at the
// SampleThemeDir path.
func GenTheme(exitOnErr bool) {
	util.MakeDir(SampleThemeDir, exitOnErr)
	files := []string{Theme.Index, Theme.Image, Theme.Set, Theme.Sets,
		Theme.Text, Theme.AlbumCSS, Theme.LightboxCSS}
	for _, f := range files {
		content, _ := ThemeFile.ReadFile(filepath.Join(SampleThemeDir, f))
		util.SaveFile(filepath.Join(SampleThemeDir, f), string(content),
			exitOnErr)
	}
}

// GetSetHTML returns an HTML string of image thumbnails for an image set.
//
// linkClass and thumbClass are CSS classes to assign to the links and
// thumbnails respectively for styling.
//
// If imageType is "image", the HTML target links will link directly to
// images instead of their corresponding HTML pages.
//
// If lightboxOn is true, the HTML target links will be set to anchors
// that are image iframe ids.
func GetSetHTML(srcPath, thumbPath, sortOrder, linkType, linkClass,
	thumbClass string, lightboxOn, isTopLevel bool) string {
	var htmlStr string
	files := image.GetImageList(srcPath, sortOrder, false)
	imgVars := map[string]string{
		PartVar["linkClass"]:  linkClass,
		PartVar["thumbClass"]: thumbClass,
	}
	if linkType == "image" {
		for _, file := range files {
			// Adjust path for top-level page.
			if isTopLevel {
				imgVars[PartVar["link"]] = file
			} else {
				imgVars[PartVar["link"]] = filepath.Base(file)
			}
			imgVars[PartVar["thumb"]] = filepath.Join(thumbPath,
				filepath.Base(file))
			htmlStr += util.MultiReplace(PartHTML["img"], imgVars)
		}
	} else {
		for _, file := range files {
			if lightboxOn {
				imgVars[PartVar["link"]] = "#" +
					util.ReplaceExt(filepath.Base(file), "")
			} else if !lightboxOn && isTopLevel {
				imgVars[PartVar["link"]] = strings.Replace(file,
					filepath.Ext(file), filepath.Ext(Theme.Index), 1)
			} else {
				imgVars[PartVar["link"]] = filepath.Base(
					strings.Replace(file,
						filepath.Ext(file), filepath.Ext(Theme.Index), 1))
			}
			imgVars[PartVar["thumb"]] = filepath.Join(thumbPath,
				filepath.Base(file))
			htmlStr += util.MultiReplace(PartHTML["img"], imgVars)
		}
	}
	return strings.TrimRight(htmlStr, "\n")
}

// GetSetLBHTML returns an HTML string of image iframes and navigation links for // an image set.
//
// iframeClass is a CSS class to assign to the iframes for styling.
func GetSetLBHTML(srcPath, sortOrder, iframeClass string,
	isTopLevel bool) string {
	var htmlStr string
	files := image.GetImageList(srcPath, sortOrder, false)
	lbVars := map[string]string{
		PartVar["iframeClass"]: iframeClass,
	}
	for f := 0; f < len(files); f++ {
		prev, next := "#", "#"
		if len(files) > 1 {
			if f == 0 {
				next = "#" + util.ReplaceExt(filepath.Base(files[f+1]), "")
			} else if f == (len(files) - 1) {
				prev = "#" + util.ReplaceExt(filepath.Base(files[f-1]), "")
				next = "#"
			} else {
				prev = "#" + util.ReplaceExt(filepath.Base(files[f-1]), "")
				next = "#" + util.ReplaceExt(filepath.Base(files[f+1]), "")
			}
		}
		lbVars[PartVar["navNext"]] = next
		lbVars[PartVar["navPrev"]] = prev
		lbVars[PartVar["id"]] = util.ReplaceExt(filepath.Base(files[f]), "")
		if isTopLevel {
			lbVars[PartVar["link"]] = strings.Replace(files[f],
				filepath.Ext(files[f]), filepath.Ext(Theme.Index), 1)
		} else {
			lbVars[PartVar["link"]] = filepath.Base(strings.Replace(
				files[f], filepath.Ext(files[f]), filepath.Ext(Theme.Index), 1))
		}
		htmlStr += util.MultiReplace(PartHTML["lightbox"], lbVars)
	}
	return strings.TrimRight(htmlStr, "\n")
}

// TxtToHTML returns an HTML string with supported markup syntax in string str
// replaced with  HTML tags.
func TxtToHTML(str string) string {
	htmlStr := html.EscapeString(str)
	for _, r := range MarkupTxt {
		for reg, repl := range r {
			re, _ := regexp.Compile(reg)
			htmlStr = string(re.ReplaceAll([]byte(htmlStr), []byte(repl)))
		}
	}
	htmlStr = "<p>" + strings.TrimRight(htmlStr, "\n") + "</p>"
	return htmlStr
}

// FilterHTML returns an HTML string with some characters escaped
// (see html.EscapeString) and supported markup tags exempted.
func FilterHTML(str string) string {
	htmlStr := html.EscapeString(str)
	htmlStr = strings.TrimRight(util.MultiReplace(htmlStr, MarkupHTML), "\n")
	return htmlStr
}

// GetCaption returns an HTML string with the contents of an image caption for
// string path, if the caption file exists. If the caption file does not exist,
// returns an empty string.
func GetCaption(path string) string {
	for _, ext := range CaptionExt {
		capPath := path
		if strings.HasSuffix(path, filepath.Ext(path)) &&
			filepath.Ext(path) != "" {
			// Files.
			capPath = strings.Replace(path, filepath.Ext(path), ext, 1)
		} else {
			// Directories.
			capPath += ext
		}
		if util.FileExists(capPath) {
			if ext == ".txt" {
				return TxtToHTML(util.LoadFile(capPath))
			} else if ext == ".html" {
				return FilterHTML(util.LoadFile(capPath))
			}
		}
	}
	return ""
}

// Like GetCaption but for multiple files in a directory at string path,
// GetCaptions a map with image files as keys and caption contents as values.
//
// If titleFallback is true, sets the caption contents to the image title
// if no caption file is found for a given image.
func GetCaptions(path string, titleFallback bool) map[string]string {
	caps := make(map[string]string)
	files := image.GetImageList(path, "name", false)
	// Load caption file if available, fallback to deriving title from the
	// filename if title fallback is enabled, or empty string if unknown.
	for _, file := range files {
		caps[file] = GetCaption(file)
		if caps[file] == "" && titleFallback {
			caps[file] = image.GetImageTitle(file)
		}
	}
	return caps
}

// CopyCSS copies the theme CSS files from themePath to destDir.
func CopyCSS(themePath, destDir string) {
	util.MakeDir(destDir, true)
	util.CopyFile(filepath.Join(themePath, Theme.LightboxCSS),
		filepath.Join(destDir, Theme.LightboxCSS))
	util.CopyFile(filepath.Join(themePath, Theme.AlbumCSS),
		filepath.Join(destDir, Theme.AlbumCSS))
}

// PrepImages copies images in Set set to destDir, and creates a directory of
// thumbnails at destDir.
func PrepImages(destDir string, set Set) {
	dsPath := filepath.FromSlash(destDir)
	util.MakeDir(filepath.Join(dsPath, set.ImageDir))
	image.CopyImages(set.ImageDir, filepath.Join(dsPath, set.ImageDir),
		false)

	util.MakeDir(filepath.Join(dsPath, set.ImageDir, set.ThumbDir))
	image.ResizeImages(filepath.Join(dsPath, set.ImageDir),
		filepath.Join(dsPath, set.ImageDir, set.ThumbDir),
		set.ThumbWidth, set.ThumbHeight, set.ThumbPct, set.ThumbClip,
		set.ThumbUnifyMode, false)
}

// GetPartial returns an HTML string of partial themeFile from theme themePath
// with template variables partialVars inserted.
func GetPartial(themePath, themeFile string,
	partialVars map[string]string) string {
	// Replace variables in partial template and trim end of file newlines.
	partial := util.LoadFile(filepath.Join(filepath.FromSlash(themePath),
		themeFile))
	return strings.TrimRight(util.MultiReplace(partial, partialVars),
		"\n")
}

// MakePage saves a page at destPath with the contents of themeFile from
// themePath and the values from pageVars template variables inserted.
func MakePage(themePath, themeFile, destPath string,
	pageVars map[string]string) {
	// Replace variables in index template.
	dsPath := filepath.FromSlash(destPath)
	util.MakeDir(filepath.Dir(dsPath))
	index := util.LoadFile(filepath.Join(filepath.FromSlash(themePath),
		themeFile))
	page := util.MultiReplace(index, pageVars)
	os.Remove(dsPath)
	util.SaveFile(dsPath, page)
}

// MakeHTMLImagePages saves individual HTML pages for set images at destDir.
func MakeHTMLImagePages(themePath, destDir string, sets []Set) {
	for _, set := range sets {
		util.MakeDir(filepath.Join(destDir, set.ImageDir))
		caps := GetCaptions(set.ImageDir, true)
		files := image.GetImageList(set.ImageDir, set.SortOrder, false)

		PrepImages(destDir, set)
		for f := 0; f < len(files); f++ {
			nav := ""
			// No nav HTML emitted in lightbox mode.
			if !set.LightboxOn {
				prev, next := "#", "#"
				if len(files) > 1 {
					if f == 0 {
						next = util.ReplaceExt(filepath.Base(files[f+1]),
							filepath.Ext(Theme.Index))
					} else if f == (len(files) - 1) {
						prev = util.ReplaceExt(filepath.Base(files[f-1]),
							filepath.Ext(Theme.Index))
						next = "#"
					} else {
						prev = util.ReplaceExt(filepath.Base(files[f-1]),
							filepath.Ext(Theme.Index))
						next = util.ReplaceExt(filepath.Base(files[f+1]),
							filepath.Ext(Theme.Index))
					}
				}
				navVars := map[string]string{
					PartVar["navNext"]: next,
					PartVar["navPrev"]: prev,
					PartVar["navTop"]:  set.IndexHTML,
				}
				nav = util.MultiReplace(PartVar["nav"], navVars)
			}
			partialVars := map[string]string{
				ThemeVar[Theme.Image]["caption"]: caps[files[f]],
				ThemeVar[Theme.Image]["path"]:    filepath.Base(files[f]),
				ThemeVar[Theme.Image]["title"]:   image.GetImageTitle(files[f]),
				ThemeVar[Theme.Image]["nav"]:     nav,
			}
			partial := GetPartial(themePath, Theme.Image, partialVars)
			pageVars := map[string]string{
				ThemeVar[Theme.Index]["content"]: partial,
				ThemeVar[Theme.Index]["relPath"]: "..",
				ThemeVar[Theme.Index]["title"]:   image.GetImageTitle(files[f]),
			}
			pagePath := filepath.Join(destDir, set.ImageDir,
				strings.Replace(filepath.Base(files[f]),
					filepath.Ext(files[f]), filepath.Ext(Theme.Index), 1))
			MakePage(themePath, Theme.Index, pagePath, pageVars)
		}
	}
}

// MakeHTMLSetPages saves a page displaying each set, if enabled in the set's
// properties, at destDir.
func MakeHTMLSetPages(themePath, destDir string, sets []Set) {
	tmPath := filepath.FromSlash(themePath)
	dsPath := filepath.FromSlash(destDir)
	setHTML := util.LoadFile(filepath.Join(tmPath, Theme.Set))
	for _, set := range sets {
		if set.IndexHTML != "" {
			// Move images if not already present.
			PrepImages(destDir, set)

			// Replace variables in partial template.
			setCont := GetSetHTML(set.ImageDir, set.ThumbDir, set.SortOrder,
				set.LinkType, set.CSSClassLink, set.CSSClassThumb,
				set.LightboxOn, false)
			setDesc := GetCaption(filepath.Join(set.ImageDir, set.ImageDir))
			setLB := ""
			if set.LightboxOn {
				setLB = GetSetLBHTML(set.ImageDir, set.SortOrder,
					set.CSSClassIframe, false)
			}
			partialVars := map[string]string{
				ThemeVar[Theme.Set]["content"]:  setCont,
				ThemeVar[Theme.Set]["desc"]:     setDesc,
				ThemeVar[Theme.Set]["lightbox"]: setLB,
				ThemeVar[Theme.Set]["name"]:     set.Name,
				ThemeVar[Theme.Set]["title"]:    set.Title,
			}
			pagePath := GetHTMLFilename(filepath.Join(dsPath, set.ImageDir,
				set.IndexHTML))
			pagePath = CheckDup(pagePath, set.ImageDir,
				filepath.Ext(Theme.Index))

			// Remove cached page.
			os.Remove(pagePath)
			setPage := strings.TrimRight(util.MultiReplace(setHTML,
				partialVars), "\n")
			// Replace variables in page template.
			pageVars := map[string]string{
				ThemeVar[Theme.Index]["content"]: setPage,
				ThemeVar[Theme.Index]["relPath"]: "..",
				ThemeVar[Theme.Index]["title"]:   image.GetImageTitle(set.Title),
			}
			MakePage(themePath, Theme.Index, pagePath, pageVars)
		}
	}
}

// MakeHTMLIndexPage saves a top-level HTML page at destDir.
func MakeHTMLIndexPage(themePath, destDir string, index map[string]string,
	sets []Set) {
	tmPath := filepath.FromSlash(themePath)
	pagePath := GetHTMLFilename(filepath.Join(filepath.FromSlash(destDir),
		index["html"]))
	var cache []string

	if index["type"] == "sets" {
		for _, set := range sets {
			setHTML := util.LoadFile(filepath.Join(tmPath, Theme.Sets))
			setCont := GetSetHTML(set.ImageDir, filepath.Join(set.ImageDir,
				set.ThumbDir), set.SortOrder, set.LinkType,
				set.CSSClassLink, set.CSSClassThumb, set.LightboxOn, true)
			setDesc := GetCaption(filepath.Join(set.ImageDir, set.ImageDir))
			setLB := ""
			if set.LightboxOn {
				setLB = GetSetLBHTML(set.ImageDir, set.SortOrder,
					set.CSSClassIframe, true)
			}
			contVar := strings.Replace(ThemeVar[Theme.Sets]["content"],
				PartVar["set"], set.Name, 1)
			descVar := strings.Replace(ThemeVar[Theme.Sets]["desc"],
				PartVar["set"], set.Name, 1)
			lbVar := strings.Replace(ThemeVar[Theme.Sets]["lightbox"],
				PartVar["set"], set.Name, 1)
			nameVar := strings.Replace(ThemeVar[Theme.Sets]["name"],
				PartVar["set"], set.Name, 1)
			titleVar := strings.Replace(ThemeVar[Theme.Sets]["title"],
				PartVar["set"], set.Name, 1)
			partialVars := map[string]string{
				contVar:  setCont,
				descVar:  setDesc,
				lbVar:    setLB,
				nameVar:  set.Name,
				titleVar: set.Title,
			}

			// Remove cached page in the first pass.
			// For subsequent sets on the same page, save file directly after
			// replacing variables in the file already in the output directory.
			if !slices.Contains(cache, pagePath) {
				os.Remove(pagePath)
				cache = append(cache, pagePath)
				setHTML = strings.TrimRight(util.MultiReplace(setHTML,
					partialVars), "\n")
				pageVars := map[string]string{
					ThemeVar[Theme.Index]["content"]: setHTML,
					ThemeVar[Theme.Index]["relPath"]: ".",
					ThemeVar[Theme.Index]["title"]:   index["title"],
				}
				MakePage(themePath, Theme.Index, pagePath, pageVars)
			} else {
				setHTML = util.LoadFile(pagePath)
				setHTML = strings.TrimRight(util.MultiReplace(setHTML, partialVars),
					"\n")
				util.SaveFile(pagePath, setHTML)
			}
		}
	} else {
		// Text type.
		textHTML := util.LoadFile(filepath.Join(tmPath, Theme.Text))
		content := GetCaption(GetHTMLFilename(index["html"]))
		partialVars := map[string]string{
			ThemeVar[Theme.Text]["content"]: content,
			ThemeVar[Theme.Text]["title"]:   index["title"],
		}
		partial := strings.TrimRight(util.MultiReplace(textHTML,
			partialVars), "\n")
		pageVars := map[string]string{
			ThemeVar[Theme.Index]["content"]: partial,
			ThemeVar[Theme.Index]["relPath"]: ".",
			ThemeVar[Theme.Index]["title"]:   index["title"],
		}
		MakePage(themePath, Theme.Index, pagePath, pageVars)
	}
}

// MakeAlbum generates a directory of album files.
func MakeAlbum(themePath, destDir string, index map[string]string, sets []Set) {
	CopyCSS(themePath, destDir)
	MakeHTMLImagePages(themePath, destDir, sets)
	MakeHTMLSetPages(themePath, destDir, sets)
	if index["html"] != "" {
		MakeHTMLIndexPage(themePath, destDir, index, sets)
	}
}