// 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
import os.cmdline
import v.ast
import v.pref
import v.fmt
import v.util
import v.parser
import v.table
import vhelp

struct FormatOptions {
	is_l       bool
	is_c       bool
	is_js      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'],
		['netbsd', '_bsd.v', '_netbsd.v'], ['openbsd', '_bsd.v', '_openbsd.v'], ['solaris', '_solaris.v'],
		['haiku', '_haiku.v'], ['qnx', '_qnx.v']]
	FORMATTED_FILE_TOKEN         = '\@\@\@' + 'FORMATTED_FILE: '
)

fn main() {
	// if os.getenv('VFMT_ENABLE') == '' {
	// eprintln('v fmt is disabled for now')
	// exit(1)
	// }
	toolexe := os.executable()
	util.set_vroot_folder(os.dir(os.dir(os.dir(toolexe))))
	args := util.join_env_vflags_and_os_args()
	foptions := FormatOptions{
		is_c: '-c' in args
		is_js: '-js' 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: $toolexe')
		eprintln('vfmt args: ' + os.args.str())
		eprintln('vfmt env_vflags_and_os_args: ' + args.str())
		eprintln('vfmt possible_files: ' + possible_files.str())
	}
	var files := []string
	for file in possible_files {
		if !file.ends_with('.v') && !file.ends_with('.vv') {
			verror('v fmt can only be used on .v files.\nOffending file: "$file"')
			continue
		}
		if !os.exists(file) {
			verror('"$file" does not exist')
			continue
		}
		files << file
	}
	if files.len == 0 {
		vhelp.show_topic('fmt')
		exit(0)
	}
	var cli_args_no_files := []string
	for a in os.args {
		if !(a in files) {
			cli_args_no_files << a
		}
	}
	var errors := 0
	for file in files {
		fpath := os.real_path(file)
		var 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) {
	prefs := pref.new_preferences()
	if foptions.is_verbose {
		eprintln('vfmt2 running fmt.fmt over file: $file')
	}
	table := table.new_table()
	// checker := checker.new_checker(table, prefs)
	file_ast := parser.parse_file(file, table, .parse_comments, prefs, &ast.Scope{
		parent: 0
	})
	// checker.check(file_ast)
	formatted_content := fmt.fmt(file_ast, table)
	file_name := os.file_name(file)
	vfmt_output_path := os.join_path(os.temp_dir(), 'vfmt_' + file_name)
	os.write_file(vfmt_output_path, formatted_content)
	if foptions.is_verbose {
		eprintln('fmt.fmt worked and ${formatted_content.len} bytes were written to ${vfmt_output_path} .')
	}
	eprintln('${FORMATTED_FILE_TOKEN}${vfmt_output_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('lookup_path: $compiler_params.lookup_path ')
	eprintln('   out_name: $compiler_params.out_name ')
	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, 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 || foptions.is_js {
		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 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 (f FormatOptions) str() string {
	return 'FormatOptions{ 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) {
	var mod_name := 'main'
	var 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.real_path(os.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)
	}
	var vfiles := []string
	for f in all_files_in_pfolder {
		vf := os.join_path(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`.
	var 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
}

fn verror(s string) {
	util.verror('vfmt error', s)
}