// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module main

import (
	os
	os.cmdline
	filepath
	compiler
	v.pref
	v.fmt
	v.parser
	v.table
)

struct FormatOptions {
	is_2       bool
	is_l       bool
	is_c       bool
	is_w       bool
	is_diff    bool
	is_verbose bool
	is_all     bool
	is_worker  bool
	is_debug   bool
	is_noerror bool
}

const (
	platform_and_file_extensions = [['windows', '_win.v', '_windows.v'],
	['linux', '_lin.v', '_linux.v', '_nix.v'],
	['macos', '_mac.v', '_darwin.v'],
	['freebsd', '_bsd.v', '_freebsd.v'],
	['solaris', '_solaris.v'],
	['haiku', '_haiku.v'],
	]
	FORMATTED_FILE_TOKEN = '\@\@\@' + 'FORMATTED_FILE: '
)

fn main() {
	toolexe := os.executable()
	compiler.set_vroot_folder(filepath.dir(filepath.dir(filepath.dir(toolexe))))
	args := join_flags_and_argument()
	foptions := FormatOptions{
		is_2: '-2' in args
		is_c: '-c' in args
		is_l: '-l' in args
		is_w: '-w' in args
		is_diff: '-diff' in args
		is_verbose: '-verbose' in args || '--verbose' in args
		is_all: '-all' in args || '--all' in args
		is_worker: '-worker' in args
		is_debug: '-debug' in args
		is_noerror: '-noerror' in args
	}
	if foptions.is_verbose {
		eprintln('vfmt foptions: $foptions')
	}
	if foptions.is_worker {
		// -worker should be added by a parent vfmt process.
		// We launch a sub process for each file because
		// the v compiler can do an early exit if it detects
		// a syntax error, but we want to process ALL passed
		// files if possible.
		foptions.format_file(cmdline.option(args, '-worker', ''))
		exit(0)
	}
	// we are NOT a worker at this stage, i.e. we are a parent vfmt process
	possible_files := cmdline.only_non_options(cmdline.options_after(args, ['fmt']))
	if foptions.is_verbose {
		eprintln('vfmt toolexe: $toolexe')
		eprintln('vfmt args: ' + os.args.str())
		eprintln('vfmt env_vflags_and_os_args: ' + args.str())
		eprintln('vfmt possible_files: ' + possible_files.str())
	}
	mut files := []string
	for file in possible_files {
		if foptions.is_2 {
			if !file.ends_with('.v') && !file.ends_with('.vv') {
				compiler.verror('v fmt -2 can only be used on .v or .vv files.\nOffending file: "$file" .')
				continue
			}
		} else {
			if !file.ends_with('.v') {
				compiler.verror('v fmt can only be used on .v files.\nOffending file: "$file" .')
				continue
			}
		}
		if !os.exists(file) {
			compiler.verror('"$file" does not exist.')
			continue
		}
		files << file
	}
	if files.len == 0 {
		usage()
		exit(0)
	}
	mut cli_args_no_files := []string
	for a in os.args {
		if !a in files {
			cli_args_no_files << a
		}
	}
	mut errors := 0
	for file in files {
		fpath := os.realpath(file)
		mut worker_command_array := cli_args_no_files.clone()
		worker_command_array << ['-worker', fpath]
		worker_cmd := worker_command_array.join(' ')
		if foptions.is_verbose {
			eprintln('vfmt worker_cmd: $worker_cmd')
		}
		worker_result := os.exec(worker_cmd) or {
			errors++
			continue
		}
		if worker_result.exit_code != 0 {
			eprintln(worker_result.output)
			if worker_result.exit_code == 1 {
				eprintln('vfmt error while formatting file: $file .')
			}
			errors++
			continue
		}
		if worker_result.output.len > 0 {
			if worker_result.output.contains(FORMATTED_FILE_TOKEN) {
				wresult := worker_result.output.split(FORMATTED_FILE_TOKEN)
				formatted_warn_errs := wresult[0]
				formatted_file_path := wresult[1]
				foptions.post_process_file(fpath, formatted_file_path)
				if formatted_warn_errs.len > 0 {
					eprintln(formatted_warn_errs)
				}
				continue
			}
		}
		errors++
	}
	if errors > 0 {
		eprintln('Encountered a total of: ${errors} errors.')
		if foptions.is_noerror {
			exit(0)
		}
		exit(1)
	}
}

fn (foptions &FormatOptions) format_file(file string) {
	if foptions.is_2 {
		if foptions.is_verbose {
			eprintln('vfmt2 running fmt.fmt over file: $file')
		}
		table := table.new_table()
		file_ast := parser.parse_file(file, table, .parse_comments)
		formatted_content := fmt.fmt(file_ast, table)
		file_name := filepath.filename(file)
		vfmt_output_path := filepath.join(os.tmpdir(), 'vfmt_' + file_name)
		os.write_file(vfmt_output_path, formatted_content )
		if foptions.is_verbose {
			eprintln('vfmt2 fmt.fmt worked and ${formatted_content.len} bytes were written to ${vfmt_output_path} .')
		}
		eprintln('${FORMATTED_FILE_TOKEN}${vfmt_output_path}')
		return
	}
	tmpfolder := os.tmpdir()
	mut compiler_params := &pref.Preferences{}
	target_os := file_to_target_os(file)
	if target_os != '' {
		compiler_params.os = pref.os_from_string(target_os)
	}
	mut cfile := file
	mut mod_folder_parent := tmpfolder
	is_test_file := file.ends_with('_test.v')
	mod_name,is_module_file := file_to_mod_name_and_is_module_file(file)
	use_tmp_main_program := is_module_file && !is_test_file
	mod_folder := filepath.basedir(file)
	if use_tmp_main_program {
		// TODO: remove the need for this
		// This makes a small program that imports the module,
		// so that the module files will get processed by the
		// vfmt implementation.
		mod_folder_parent = filepath.basedir(mod_folder)
		mut main_program_content := if mod_name == 'builtin' || mod_name == 'main' { 'fn main(){}\n' } else { 'import ${mod_name}\n' + 'fn main(){}\n' }
		main_program_file := filepath.join(tmpfolder,'vfmt_tmp_${mod_name}_program.v')
		if os.exists(main_program_file) {
			os.rm(main_program_file)
		}
		os.write_file(main_program_file, main_program_content)
		cfile = main_program_file
		compiler_params.user_mod_path = mod_folder_parent
	}
	if !is_test_file && mod_name == 'main' {
		// NB: here, file is guaranted to be a main. We do not know however
		// whether it is a standalone v program, or is it a part of a bigger
		// project, like vorum or vid.
		cfile = get_compile_name_of_potential_v_project(cfile)
	}
	compiler_params.path = cfile
	compiler_params.mod = mod_name
	compiler_params.is_test = is_test_file
	compiler_params.is_script = file.ends_with('.v') || file.ends_with('.vsh')
	if foptions.is_verbose {
		eprintln('vfmt format_file: file: $file')
		eprintln('vfmt format_file: cfile: $cfile')
		eprintln('vfmt format_file: is_test_file: $is_test_file')
		eprintln('vfmt format_file: is_module_file: $is_module_file')
		eprintln('vfmt format_file: mod_name: $mod_name')
		eprintln('vfmt format_file: mod_folder: $mod_folder')
		eprintln('vfmt format_file: mod_folder_parent: $mod_folder_parent')
		eprintln('vfmt format_file: use_tmp_main_program: $use_tmp_main_program')
		eprintln('vfmt format_file: compiler_params: ')
		print_compiler_options( compiler_params )
		eprintln('-------------------------------------------')
	}
	compiler_params.fill_with_defaults()
	if foptions.is_verbose {
		eprintln('vfmt format_file: compiler_params: AFTER fill_with_defaults() ')
		print_compiler_options( compiler_params )
	}
	formatted_file_path := foptions.compile_file(file, compiler_params)
	if use_tmp_main_program {
		if !foptions.is_debug {
			os.rm(cfile)
		}
	}
	eprintln('${FORMATTED_FILE_TOKEN}${formatted_file_path}')
}

fn print_compiler_options( compiler_params &pref.Preferences ) {
	eprintln('        os: ' + compiler_params.os.str() )
	eprintln(' ccompiler: $compiler_params.ccompiler' )
	eprintln('       mod: $compiler_params.mod ')
	eprintln('      path: $compiler_params.path ')
	eprintln('  out_name: $compiler_params.out_name ')
	eprintln('     vroot: $compiler_params.vroot ')
	eprintln('     vpath: $compiler_params.vpath ')
	eprintln(' vlib_path: $compiler_params.vlib_path ')
	eprintln('  out_name: $compiler_params.out_name ')
	eprintln('    umpath: $compiler_params.user_mod_path ')
	eprintln('    cflags: $compiler_params.cflags ')
	eprintln('   is_test: $compiler_params.is_test ')
	eprintln(' is_script: $compiler_params.is_script ')
}

fn (foptions &FormatOptions) post_process_file(file string, formatted_file_path string) {
	if formatted_file_path.len == 0 {
		return
	}
	if foptions.is_diff {
		diff_cmd := find_working_diff_command() or {
			eprintln('No working "diff" CLI command found.')
			return
		}
		os.system('$diff_cmd --minimal  --text   --unified=2 --show-function-line="fn " "$file" "$formatted_file_path" ')
		return
	}
	fc := os.read_file(file) or {
		eprintln('File $file could not be read')
		return
	}
	formatted_fc := os.read_file(formatted_file_path) or {
		eprintln('File $formatted_file_path could not be read')
		return
	}
	is_formatted_different := fc != formatted_fc
	if foptions.is_c {
		if is_formatted_different {
			eprintln('File is not formatted: $file')
			exit(2)
		}
		return
	}
	if foptions.is_l {
		if is_formatted_different {
			eprintln('File needs formatting: $file')
		}
		return
	}
	if foptions.is_w {
		if is_formatted_different {
			os.mv_by_cp(formatted_file_path, file) or {
				panic(err)
			}
			eprintln('Reformatted file: $file')
		}
		else {
			eprintln('Already formatted file: $file')
		}
		return
	}
	print(formatted_fc)
}

fn usage() {
	print('Usage: cmd/tools/vfmt [flags] fmt path_to_source.v [path_to_other_source.v]
Formats the given V source files, and prints their formatted source to stdout.
Options:
  -c    check if file is already formatted.
        If it is not, print filepath, and exit with code 2.
  -diff display only diffs between the formatted source and the original source.
  -l    list files whose formatting differs from vfmt.
  -w    write result to (source) file(s) instead of to stdout.
  -2    Use the new V parser/vfmt. NB: this is EXPERIMENTAL for now.
          The new vfmt is much faster and more forgiving.
          It also may EAT some of your code for now.
          Please be carefull, and make frequent BACKUPS, when running with -vfmt2 .
')
}

fn find_working_diff_command() ?string {
	for diffcmd in ['colordiff', 'diff', 'colordiff.exe', 'diff.exe'] {
		p := os.exec('$diffcmd --version') or {
			continue
		}
		if p.exit_code == 0 {
			return diffcmd
		}
	}
	return error('no working diff command found')
}

fn (foptions &FormatOptions) compile_file(file string, compiler_params &pref.Preferences) string {
	if foptions.is_verbose {
		eprintln('> new_v_compiler_with_args            file: $file')
		eprintln('> new_v_compiler_with_args compiler_params:')
		print_compiler_options( compiler_params )
	}
	mut v := compiler.new_v(compiler_params)
	v.v_fmt_file = file
	if foptions.is_all {
		v.v_fmt_all = true
	}
	v.compile()
	return v.v_fmt_file_result
}

pub fn (f FormatOptions) str() string {
	return 'FormatOptions{ ' + ' is_2: $f.is_2' + ' is_l: $f.is_l' + ' is_w: $f.is_w' + ' is_diff: $f.is_diff' + ' is_verbose: $f.is_verbose' + ' is_all: $f.is_all' + ' is_worker: $f.is_worker' + ' is_debug: $f.is_debug' + ' }'
}

fn file_to_target_os(file string) string {
	for extensions in platform_and_file_extensions {
		for ext in extensions {
			if file.ends_with(ext) {
				return extensions[0]
			}
		}
	}
	return ''
}

fn file_to_mod_name_and_is_module_file(file string) (string,bool) {
	mut mod_name := 'main'
	mut is_module_file := false
	flines := read_source_lines(file) or {
		return mod_name,is_module_file
	}
	for fline in flines {
		line := fline.trim_space()
		if line.starts_with('module ') {
			if !line.starts_with('module main') {
				is_module_file = true
				mod_name = line.replace('module ', ' ').trim_space()
			}
			break
		}
	}
	return mod_name,is_module_file
}

fn read_source_lines(file string) ?[]string {
	source_lines := os.read_lines(file) or {
		return error('can not read $file')
	}
	return source_lines
}

fn get_compile_name_of_potential_v_project(file string) string {
	// This function get_compile_name_of_potential_v_project returns:
	// a) the file's folder, if file is part of a v project
	// b) the file itself, if the file is a standalone v program
	pfolder := os.realpath(filepath.dir(file))
	// a .v project has many 'module main' files in one folder
	// if there is only one .v file, then it must be a standalone
	all_files_in_pfolder := os.ls(pfolder) or {
		panic(err)
	}
	mut vfiles := []string
	for f in all_files_in_pfolder {
		vf := filepath.join(pfolder,f)
		if f.starts_with('.') || !f.ends_with('.v') || os.is_dir(vf) {
			continue
		}
		vfiles << vf
	}
	if vfiles.len == 1 {
		return file
	}
	// /////////////////////////////////////////////////////////////
	// At this point, we know there are many .v files in the folder
	// We will have to read them all, and if there are more than one
	// containing `fn main` then the folder contains multiple standalone
	// v programs. If only one contains `fn main` then the folder is
	// a project folder, that should be compiled with `v pfolder`.
	mut main_fns := 0
	for f in vfiles {
		slines := read_source_lines(f) or {
			panic(err)
		}
		for line in slines {
			if line.contains('fn main()') {
				main_fns++
				if main_fns > 1 {
					return file
				}
			}
		}
	}
	return pfolder
}

//TODO Move join_flags_and_argument() and non_empty() into `cmd/internal` when v.mod work correctly
//to prevent code duplication with `cmd/v` (cmd/v/flag.v)
fn join_flags_and_argument() []string {
	vosargs := os.getenv('VOSARGS')
	if vosargs != '' {
		return non_empty(vosargs.split(' '))
	}

	mut args := []string
	vflags := os.getenv('VFLAGS')
	if vflags != '' {
		args << os.args[0]
		args << vflags.split(' ')
		if os.args.len > 1 {
			args << os.args[1..]
		}
		return non_empty(args)
	}

	return non_empty(os.args)
}
fn non_empty(arg []string) []string {
	return arg.filter(it != '')
}