module main

import markdown
import os
import os.cmdline
import time
import strings
import sync
import runtime
import v.doc
import v.pref
import v.vmod
import json

const (
	allowed_formats = ['md', 'markdown', 'json', 'text', 'stdout', 'html', 'htm']
	vexe            = pref.vexe_path()
	vroot           = os.dir(vexe)
	tabs            = ['\t\t', '\t\t\t\t\t\t', '\t\t\t\t\t\t\t']
)

enum OutputType {
	unset
	html
	markdown
	json
	plaintext
	stdout
}

struct VDoc {
	cfg Config [required]
mut:
	docs                []doc.Doc
	assets              map[string]string
	manifest            vmod.Manifest
	search_index        []string
	search_data         []SearchResult
	search_module_index []string // search results are split into a module part and the rest
	search_module_data  []SearchModuleResult
}

struct Config {
mut:
	pub_only         bool = true
	is_local         bool
	local_filename   string
	local_pos        int
	show_loc         bool // for plaintext
	is_multi         bool
	is_vlib          bool
	is_verbose       bool
	include_readme   bool
	include_examples bool = true
	inline_assets    bool
	no_timestamp     bool
	output_path      string
	output_type      OutputType = .unset
	input_path       string
	symbol_name      string
}

//
struct Output {
mut:
	path string
	typ  OutputType = .unset
}

struct ParallelDoc {
	d   doc.Doc
	out Output
}

fn (vd VDoc) gen_json(d doc.Doc) string {
	cfg := vd.cfg
	mut jw := strings.new_builder(200)
	comments := if cfg.include_examples {
		d.head.merge_comments()
	} else {
		d.head.merge_comments_without_examples()
	}
	jw.write_string('{"module_name":"$d.head.name","description":"${escape(comments)}","contents":')
	jw.write_string(json.encode(d.contents.keys().map(d.contents[it])))
	jw.write_string(',"generator":"vdoc","time_generated":"$d.time_generated.str()"}')
	return jw.str()
}

fn (vd VDoc) gen_plaintext(d doc.Doc) string {
	cfg := vd.cfg
	mut pw := strings.new_builder(200)
	pw.writeln('$d.head.content\n')
	comments := if cfg.include_examples {
		d.head.merge_comments()
	} else {
		d.head.merge_comments_without_examples()
	}
	if comments.trim_space().len > 0 && !cfg.pub_only {
		pw.writeln(comments.split_into_lines().map('    ' + it).join('\n'))
	}
	vd.write_plaintext_content(d.contents.arr(), mut pw)
	return pw.str()
}

fn (vd VDoc) write_plaintext_content(contents []doc.DocNode, mut pw strings.Builder) {
	cfg := vd.cfg
	for cn in contents {
		if cn.content.len > 0 {
			pw.writeln(cn.content)
			if cn.comments.len > 0 && !cfg.pub_only {
				comments := if cfg.include_examples {
					cn.merge_comments()
				} else {
					cn.merge_comments_without_examples()
				}
				pw.writeln(comments.trim_space().split_into_lines().map('    ' + it).join('\n'))
			}
			if cfg.show_loc {
				pw.writeln('Location: $cn.file_path:$cn.pos.line\n')
			}
		}
		vd.write_plaintext_content(cn.children, mut pw)
	}
}

fn (vd VDoc) render_doc(d doc.Doc, out Output) (string, string) {
	name := vd.get_file_name(d.head.name, out)
	output := match out.typ {
		.html { vd.gen_html(d) }
		.markdown { vd.gen_markdown(d, true) }
		.json { vd.gen_json(d) }
		else { vd.gen_plaintext(d) }
	}
	return name, output
}

// get_file_name returns the final file name from a module name
fn (vd VDoc) get_file_name(mod string, out Output) string {
	cfg := vd.cfg
	mut name := mod
	// since builtin is generated first, ignore it
	if (cfg.is_vlib && mod == 'builtin' && !cfg.include_readme) || mod == 'README' {
		name = 'index'
	} else if !cfg.is_multi && !os.is_dir(out.path) {
		name = os.file_name(out.path)
	}
	name = name + match out.typ {
		.html { '.html' }
		.markdown { '.md' }
		.json { '.json' }
		else { '.txt' }
	}
	return name
}

fn (vd VDoc) work_processor(mut work sync.Channel, mut wg sync.WaitGroup) {
	for {
		mut pdoc := ParallelDoc{}
		if !work.pop(&pdoc) {
			break
		}
		file_name, content := vd.render_doc(pdoc.d, pdoc.out)
		output_path := os.join_path(pdoc.out.path, file_name)
		println('Generating $pdoc.out.typ in "$output_path"')
		os.write_file(output_path, content) or { panic(err) }
	}
	wg.done()
}

fn (vd VDoc) render_parallel(out Output) {
	vjobs := runtime.nr_jobs()
	mut work := sync.new_channel<ParallelDoc>(vd.docs.len)
	mut wg := sync.new_waitgroup()
	for i in 0 .. vd.docs.len {
		p_doc := ParallelDoc{vd.docs[i], out}
		work.push(&p_doc)
	}
	work.close()
	wg.add(vjobs)
	for _ in 0 .. vjobs {
		go vd.work_processor(mut work, mut wg)
	}
	wg.wait()
}

fn (vd VDoc) render(out Output) map[string]string {
	mut docs := map[string]string{}
	for doc in vd.docs {
		name, output := vd.render_doc(doc, out)
		docs[name] = output.trim_space()
	}
	vd.vprintln('Rendered: ' + docs.keys().str())
	return docs
}

fn (vd VDoc) get_readme(path string) string {
	mut fname := ''
	for name in ['readme', 'README'] {
		if os.exists(os.join_path(path, '${name}.md')) {
			fname = name
			break
		}
	}
	if fname == '' {
		return ''
	}
	readme_path := os.join_path(path, '${fname}.md')
	vd.vprintln('Reading README file from $readme_path')
	readme_contents := os.read_file(readme_path) or { '' }
	return readme_contents
}

fn (vd VDoc) emit_generate_err(err string, errcode int) {
	cfg := vd.cfg
	mut err_msg := err
	if errcode == 1 {
		mod_list := get_modules_list(cfg.input_path, []string{})
		println('Available modules:\n==================')
		for mod in mod_list {
			println(mod.all_after('vlib/').all_after('modules/').replace('/', '.'))
		}
		err_msg += ' Use the `-m` flag when generating docs from a directory that has multiple modules.'
	}
	eprintln(err_msg)
}

fn (mut vd VDoc) generate_docs_from_file() {
	cfg := vd.cfg
	mut out := Output{
		path: cfg.output_path
		typ: cfg.output_type
	}
	if out.path.len == 0 {
		if cfg.output_type == .unset {
			out.typ = .stdout
		} else {
			vd.vprintln('No output path has detected. Using input path instead.')
			out.path = cfg.input_path
		}
	} else if out.typ == .unset {
		vd.vprintln('Output path detected. Identifying output type..')
		ext := os.file_ext(out.path)
		out.typ = set_output_type_from_str(ext.all_after('.'))
	}
	if cfg.include_readme && out.typ !in [.html, .stdout] {
		eprintln('vdoc: Including README.md for doc generation is supported on HTML output, or when running directly in the terminal.')
		exit(1)
	}
	dir_path := if cfg.is_vlib {
		vroot
	} else if os.is_dir(cfg.input_path) {
		cfg.input_path
	} else {
		os.dir(cfg.input_path)
	}
	manifest_path := os.join_path(dir_path, 'v.mod')
	if os.exists(manifest_path) {
		vd.vprintln('Reading v.mod info from $manifest_path')
		if manifest := vmod.from_file(manifest_path) {
			vd.manifest = manifest
		}
	}
	if cfg.include_readme {
		readme_contents := vd.get_readme(dir_path)
		comment := doc.DocComment{
			text: readme_contents
		}
		if out.typ == .stdout {
			println(markdown.to_plain(readme_contents))
		} else if out.typ == .html && cfg.is_multi {
			vd.docs << doc.Doc{
				head: doc.DocNode{
					name: 'README'
					comments: [comment]
				}
				time_generated: time.now()
			}
		}
	}
	dirs := if cfg.is_multi {
		get_modules_list(cfg.input_path, []string{})
	} else {
		[cfg.input_path]
	}
	is_local_and_single := cfg.is_local && !cfg.is_multi
	for dirpath in dirs {
		mut dcs := doc.Doc{}
		vd.vprintln('Generating $out.typ docs for "$dirpath"')
		if is_local_and_single {
			dcs = doc.generate_with_pos(dirpath, cfg.local_filename, cfg.local_pos) or {
				vd.emit_generate_err(err, errcode)
				exit(1)
			}
		} else {
			dcs = doc.generate(dirpath, cfg.pub_only, true) or {
				vd.emit_generate_err(err, errcode)
				exit(1)
			}
		}
		if dcs.contents.len == 0 {
			continue
		}
		if !is_local_and_single {
			if cfg.is_multi || (!cfg.is_multi && cfg.include_readme) {
				readme_contents := vd.get_readme(dirpath)
				comment := doc.DocComment{
					text: readme_contents
				}
				dcs.head.comments = [comment]
			}
			if cfg.pub_only {
				for name, dc in dcs.contents {
					dcs.contents[name].content = dc.content.all_after('pub ')
					for i, cc in dc.children {
						dcs.contents[name].children[i].content = cc.content.all_after('pub ')
					}
				}
			}
			if !cfg.is_multi && cfg.symbol_name.len > 0 {
				if cfg.symbol_name in dcs.contents {
					for _, c in dcs.contents[cfg.symbol_name].children {
						dcs.contents[c.name] = c
					}
				}
			}
		}
		vd.docs << dcs
	}
	// Important. Let builtin be in the top of the module list
	// if we are generating docs for vlib.
	if cfg.is_vlib {
		mut docs := vd.docs.filter(it.head.name == 'builtin')
		docs << vd.docs.filter(it.head.name != 'builtin')
		vd.docs = docs
	}
	vd.vprintln('Rendering docs...')
	if out.path.len == 0 || out.path == 'stdout' {
		if out.typ == .html {
			vd.render_static_html(out)
		}
		outputs := vd.render(out)
		if outputs.len == 0 {
			println('No documentation for $dirs')
		} else {
			first := outputs.keys()[0]
			println(outputs[first])
		}
	} else {
		if !os.is_dir(out.path) {
			out.path = os.real_path('.')
		}
		if !os.exists(out.path) {
			os.mkdir(out.path) or { panic(err) }
		}
		if cfg.is_multi {
			out.path = os.join_path(out.path, '_docs')
			if !os.exists(out.path) {
				os.mkdir(out.path) or { panic(err) }
			} else {
				for fname in css_js_assets {
					os.rm(os.join_path(out.path, fname)) or { panic(err) }
				}
			}
		}
		if out.typ == .html {
			vd.render_static_html(out)
		}
		vd.render_parallel(out)
		if out.typ == .html {
			println('Creating search index...')
			vd.collect_search_index(out)
			vd.render_search_index(out)
			// move favicons to target directory
			println('Copying favicons...')
			favicons := os.ls(favicons_path) or { panic(err) }
			for favicon in favicons {
				favicon_path := os.join_path(favicons_path, favicon)
				destination_path := os.join_path(out.path, favicon)
				os.cp(favicon_path, destination_path) or { panic(err) }
			}
		}
	}
}

fn (vd VDoc) vprintln(str string) {
	if vd.cfg.is_verbose {
		println('vdoc: $str')
	}
}

fn parse_arguments(args []string) Config {
	mut cfg := Config{}
	for i := 0; i < args.len; i++ {
		arg := args[i]
		current_args := args[i..]
		match arg {
			'-all' {
				cfg.pub_only = false
			}
			'-filename' {
				cfg.is_local = true
				cfg.local_filename = cmdline.option(current_args, '-filename', '')
				i++
			}
			'-f' {
				format := cmdline.option(current_args, '-f', '')
				if format !in allowed_formats {
					allowed_str := allowed_formats.join(', ')
					eprintln('vdoc: "$format" is not a valid format. Only $allowed_str are allowed.')
					exit(1)
				}
				cfg.output_type = set_output_type_from_str(format)
				i++
			}
			'-inline-assets' {
				cfg.inline_assets = true
			}
			'-l' {
				cfg.show_loc = true
			}
			'-m' {
				cfg.is_multi = true
			}
			'-o' {
				opath := cmdline.option(current_args, '-o', '')
				cfg.output_path = if opath == 'stdout' { opath } else { os.real_path(opath) }
				i++
			}
			'-pos' {
				if !cfg.is_local {
					eprintln('vdoc: `-pos` is only allowed with `-filename` flag.')
					exit(1)
				}
				cfg.local_pos = cmdline.option(current_args, '-pos', '').int()
				i++
			}
			'-no-timestamp' {
				cfg.no_timestamp = true
			}
			'-no-examples' {
				cfg.include_examples = false
			}
			'-readme' {
				cfg.include_readme = true
			}
			'-v' {
				cfg.is_verbose = true
			}
			else {
				if cfg.input_path.len < 1 {
					cfg.input_path = arg
				} else {
					cfg.symbol_name = arg
				}
				if i == args.len - 1 {
					break
				}
			}
		}
	}
	// Correct from configuration from user input
	if cfg.output_path == 'stdout' && cfg.output_type == .html {
		cfg.inline_assets = true
	}
	$if windows {
		cfg.input_path = cfg.input_path.replace('/', os.path_separator)
	} $else {
		cfg.input_path = cfg.input_path.replace('\\', os.path_separator)
	}
	is_path := cfg.input_path.ends_with('.v') || cfg.input_path.split(os.path_separator).len > 1
		|| cfg.input_path == '.'
	if cfg.input_path.trim_right('/') == 'vlib' {
		cfg.is_vlib = true
		cfg.is_multi = true
		cfg.input_path = os.join_path(vroot, 'vlib')
	} else if !is_path {
		// TODO vd.vprintln('Input "$cfg.input_path" is not a valid path. Looking for modules named "$cfg.input_path"...')
		mod_path := doc.lookup_module(cfg.input_path) or {
			eprintln('vdoc: $err')
			exit(1)
		}
		cfg.input_path = mod_path
	}
	return cfg
}

fn main() {
	if os.args.len < 2 || '-h' in os.args || '--help' in os.args || os.args[1..] == ['doc', 'help'] {
		os.system('$vexe help doc')
		exit(0)
	}
	args := os.args[2..].clone()
	cfg := parse_arguments(args)
	if cfg.input_path.len == 0 {
		eprintln('vdoc: No input path found.')
		exit(1)
	}
	// Config is immutable from this point on
	mut vd := VDoc{
		cfg: cfg
		manifest: vmod.Manifest{
			repo_url: ''
		}
	}
	vd.vprintln('Setting output type to "$cfg.output_type"')
	vd.generate_docs_from_file()
}