module embedfs

import os
import strings
import net.http.mime

pub struct CodeGenerator {
pub:
	// Path to file or directory to embed
	path string @[required]
	// Path prefix if you want to add extra prefix for file paths
	prefix string
	// Glob patterns to match files the must be ignored when generating the code
	ignore_patterns []string
	// If true set the default MIME-type for files if no MIME-type detected
	force_mimetype bool
	// Default MIME-type for files. See https://www.iana.org/assignments/media-types/media-types.xhtml
	default_mimetype string = 'application/octet-stream'
	// Name of generated module
	module_name string = 'main'
	// Name of constant which will contain embedded files
	const_name string = 'embedfs'
	// If true make constant public
	make_const_pub bool
	// If true make all symbols in generated module public
	make_pub bool
	// Generate map[string]EmbedFile instead of EmbedFileSystem instance
	bare_map bool
}

struct EmbedFileSpec {
	key      string
	path     string
	name     string
	ext      string
	mimetype string
}

pub fn (g CodeGenerator) generate() string {
	visible := if g.make_pub == true { 'pub ' } else { '' }
	const_visible := if g.make_pub == true || g.make_const_pub == true { 'pub ' } else { '' }
	mut b := strings.new_builder(1024 * 4)
	b.writeln('// !WARNING! This file is generated by embedfs module, do not edit it.')
	b.writeln('')
	b.writeln('module ${g.module_name}')
	b.writeln('')
	b.writeln('import v.embed_file { EmbedFileData }')
	b.writeln('')
	b.writeln('${visible}struct EmbedFileMetadata {')
	b.writeln('\tkey      string')
	b.writeln('\tname     string')
	b.writeln('\text      string')
	b.writeln('\tmimetype string')
	b.writeln('}')
	b.writeln('')
	b.writeln('${visible}struct EmbedFile {')
	b.writeln('\tdata EmbedFileData')
	b.writeln('\tmeta EmbedFileMetadata')
	b.writeln('}')
	b.writeln('')
	b.writeln('${visible}struct EmbedFileSystem {')
	b.writeln('\tfiles map[string]EmbedFile')
	b.writeln('}')
	b.writeln('')
	if g.bare_map {
		b.writeln('${const_visible}const ${g.const_name} = {')
		g.write_embed_file_map_item(mut b)
		b.writeln('}')
	} else {
		b.writeln('${const_visible}const ${g.const_name} = EmbedFileSystem{')
		b.writeln('\tfiles: {')
		g.write_embed_file_map_item(mut b)
		b.writeln('\t}')
		b.writeln('}')
	}
	return b.str()
}

fn (g CodeGenerator) get_files() []EmbedFileSpec {
	mut file_list := &[]string{}
	os.walk(g.path, fn [mut file_list] (file string) {
		file_list << file
	})
	mut files := []EmbedFileSpec{}
	outer: for file in file_list {
		for glob in g.ignore_patterns {
			if file.match_glob(glob) {
				continue outer
			}
		}
		file_key := os.join_path_single(g.prefix, file)
		file_path := file // the actual path used in $embed_file() statement
		file_name := os.file_name(file_path)
		file_ext := os.file_ext(file_name).replace_once('.', '')
		mut mimetype := mime.get_mime_type(file_ext)
		if g.force_mimetype && mimetype == '' {
			mimetype = g.default_mimetype
		}
		files << EmbedFileSpec{
			key:      file_key
			path:     file_path
			name:     file_name
			ext:      file_ext
			mimetype: mimetype
		}
	}
	return files
}

fn (g CodeGenerator) write_embed_file_map_item(mut b strings.Builder) {
	for filespec in g.get_files() {
		b.writeln("\t\t'${filespec.key}': EmbedFile{")
		b.writeln("\t\t\tdata: \$embed_file('${filespec.path}')")
		b.writeln('\t\t\tmeta: EmbedFileMetadata{')
		b.writeln("\t\t\t\tkey: '${filespec.key}'")
		b.writeln("\t\t\t\tname: '${filespec.name}'")
		b.writeln("\t\t\t\text: '${filespec.ext}'")
		b.writeln("\t\t\t\tmimetype: '${filespec.mimetype}'")
		b.writeln('\t\t\t}')
		b.writeln('\t\t},')
	}
}