// Copyright (c) 2019-2023 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 rand
import term
import v.help
import regex

const (
    too_long_line_length_example   = 120
    too_long_line_length_codeblock = 120
    too_long_line_length_table     = 120
    too_long_line_length_link      = 150
    too_long_line_length_other     = 100
    term_colors                    = term.can_show_color_on_stderr()
    hide_warnings                  = '-hide-warnings' in os.args || '-w' in os.args
    show_progress                  = os.getenv('GITHUB_JOB') == '' && '-silent' !in os.args
    non_option_args                = cmdline.only_non_options(os.args[2..])
    is_verbose                     = os.getenv('VERBOSE') != ''
    vcheckfolder                   = os.join_path(os.vtmp_dir(), 'v', 'vcheck_${os.getuid()}')
    should_autofix                 = os.getenv('VAUTOFIX') != ''
    vexe                           = @VEXE
)

struct CheckResult {
pub mut:
    warnings int
    errors   int
    oks      int
}

fn (v1 CheckResult) + (v2 CheckResult) CheckResult {
    return CheckResult{
        warnings: v1.warnings + v2.warnings
        errors: v1.errors + v2.errors
        oks: v1.oks + v2.oks
    }
}

fn main() {
    if non_option_args.len == 0 || '-help' in os.args {
        help.print_and_exit('check-md')
        exit(0)
    }
    if '-all' in os.args {
        println('´-all´ flag is deprecated. Please use ´v check-md .´ instead.')
        exit(1)
    }
    mut skip_line_length_check := '-skip-line-length-check' in os.args
    if show_progress {
        // this is intended to be replaced by the progress lines
        println('')
    }
    mut files_paths := non_option_args.clone()
    mut res := CheckResult{}
    if term_colors {
        os.setenv('VCOLORS', 'always', true)
    }
    os.mkdir_all(vcheckfolder, mode: 0o700) or {} // keep directory private
    defer {
        os.rmdir_all(vcheckfolder) or {}
    }
    for i := 0; i < files_paths.len; i++ {
        file_path := files_paths[i]
        if os.is_dir(file_path) {
            files_paths << md_file_paths(file_path)
            continue
        }
        real_path := os.real_path(file_path)
        lines := os.read_lines(real_path) or {
            println('"${file_path}" does not exist')
            res.warnings++
            continue
        }
        mut mdfile := MDFile{
            skip_line_length_check: skip_line_length_check
            path: file_path
            lines: lines
        }
        res += mdfile.check()
    }
    if res.errors == 0 && show_progress {
        clear_previous_line()
    }
    if res.warnings > 0 || res.errors > 0 || res.oks > 0 {
        println('\nWarnings: ${res.warnings} | Errors: ${res.errors} | OKs: ${res.oks}')
    }
    if res.errors > 0 {
        exit(1)
    }
}

fn md_file_paths(dir string) []string {
    mut files_to_check := []string{}
    md_files := os.walk_ext(dir, '.md')
    for file in md_files {
        nfile := file.replace('\\', '/')
        if nfile.contains_any_substr(['/thirdparty/', 'CHANGELOG']) {
            continue
        }
        files_to_check << file
    }
    return files_to_check
}

fn wprintln(s string) {
    if !hide_warnings {
        println(s)
    }
}

fn ftext(s string, cb fn (string) string) string {
    if term_colors {
        return cb(s)
    }
    return s
}

fn btext(s string) string {
    return ftext(s, term.bold)
}

fn mtext(s string) string {
    return ftext(s, term.magenta)
}

fn rtext(s string) string {
    return ftext(s, term.red)
}

fn wline(file_path string, lnumber int, column int, message string) string {
    return btext('${file_path}:${lnumber + 1}:${column + 1}:') + btext(mtext(' warn:')) +
        rtext(' ${message}')
}

fn eline(file_path string, lnumber int, column int, message string) string {
    return btext('${file_path}:${lnumber + 1}:${column + 1}:') + btext(rtext(' error: ${message}'))
}

const default_command = 'compile'

struct VCodeExample {
mut:
    text    []string
    command string
    sline   int
    eline   int
}

enum MDFileParserState {
    markdown
    vexample
    codeblock
}

struct MDFile {
    path                   string
    skip_line_length_check bool
mut:
    lines    []string
    examples []VCodeExample
    current  VCodeExample
    state    MDFileParserState = .markdown
}

fn (mut f MDFile) progress(message string) {
    if show_progress {
        clear_previous_line()
        println('File: ${f.path:-30s}, Lines: ${f.lines.len:5}, ${message}')
    }
}

fn (mut f MDFile) check() CheckResult {
    mut res := CheckResult{}
    mut anchor_data := AnchorData{}
    for j, line in f.lines {
        // f.progress('line: $j')
        if !f.skip_line_length_check {
            if f.state == .vexample {
                if line.len > too_long_line_length_example {
                    wprintln(wline(f.path, j, line.len, 'example lines must be less than ${too_long_line_length_example} characters'))
                    wprintln(line)
                    res.warnings++
                }
            } else if f.state == .codeblock {
                if line.len > too_long_line_length_codeblock {
                    wprintln(wline(f.path, j, line.len, 'code lines must be less than ${too_long_line_length_codeblock} characters'))
                    wprintln(line)
                    res.warnings++
                }
            } else if line.starts_with('|') {
                if line.len > too_long_line_length_table {
                    wprintln(wline(f.path, j, line.len, 'table lines must be less than ${too_long_line_length_table} characters'))
                    wprintln(line)
                    res.warnings++
                }
            } else if line.contains('http') {
                if line.all_after('https').len > too_long_line_length_link {
                    wprintln(wline(f.path, j, line.len, 'link lines must be less than ${too_long_line_length_link} characters'))
                    wprintln(line)
                    res.warnings++
                }
            } else if line.len > too_long_line_length_other {
                eprintln(eline(f.path, j, line.len, 'must be less than ${too_long_line_length_other} characters'))
                eprintln(line)
                res.errors++
            }
        }
        if f.state == .markdown {
            anchor_data.add_links(j, line)
            anchor_data.add_link_targets(j, line)
        }

        f.parse_line(j, line)
    }
    anchor_data.check_link_target_match(f.path, mut res)
    res += f.check_examples()
    return res
}

fn (mut f MDFile) parse_line(lnumber int, line string) {
    if line.starts_with('```v') {
        if f.state == .markdown {
            f.state = .vexample
            mut command := line.replace('```v', '').trim_space()
            if command == '' {
                command = default_command
            } else if command == 'nofmt' {
                command += ' ${default_command}'
            }
            f.current = VCodeExample{
                sline: lnumber
                command: command
            }
        }
        return
    }
    if line.starts_with('```') {
        match f.state {
            .vexample {
                f.state = .markdown
                f.current.eline = lnumber
                f.examples << f.current
                f.current = VCodeExample{}
                return
            }
            .codeblock {
                f.state = .markdown
                return
            }
            .markdown {
                f.state = .codeblock
                return
            }
        }
    }
    if f.state == .vexample {
        f.current.text << line
    }
}

struct Headline {
    line  int
    lable string
    level int
}

struct Anchor {
    line int
}

type AnchorTarget = Anchor | Headline

struct AnchorLink {
    line  int
    lable string
}

struct AnchorData {
mut:
    links   map[string][]AnchorLink
    anchors map[string][]AnchorTarget
}

fn (mut ad AnchorData) add_links(line_number int, line string) {
    query := r'\[(?P<lable>[^\]]+)\]\(\s*#(?P<link>[a-z0-9\-\_\x7f-\uffff]+)\)'
    mut re := regex.regex_opt(query) or { panic(err) }
    res := re.find_all_str(line)

    for elem in res {
        re.match_string(elem)
        link := re.get_group_by_name(elem, 'link')
        ad.links[link] << AnchorLink{
            line: line_number
            lable: re.get_group_by_name(elem, 'lable')
        }
    }
}

fn (mut ad AnchorData) add_link_targets(line_number int, line string) {
    if line.trim_space().starts_with('#') {
        if headline_start_pos := line.index(' ') {
            headline := line.substr(headline_start_pos + 1, line.len)
            link := create_ref_link(headline)
            ad.anchors[link] << Headline{
                line: line_number
                lable: headline
                level: headline_start_pos
            }
        }
    } else {
        query := '<a\\s*id=["\'](?P<link>[a-z0-9\\-\\_\\x7f-\\uffff]+)["\']\\s*/>'
        mut re := regex.regex_opt(query) or { panic(err) }
        res := re.find_all_str(line)

        for elem in res {
            re.match_string(elem)
            link := re.get_group_by_name(elem, 'link')
            ad.anchors[link] << Anchor{
                line: line_number
            }
        }
    }
}

fn (mut ad AnchorData) check_link_target_match(fpath string, mut res CheckResult) {
    mut checked_headlines := []string{}
    mut found_error_warning := false
    for link, linkdata in ad.links {
        if link in ad.anchors {
            checked_headlines << link
            if ad.anchors[link].len > 1 {
                found_error_warning = true
                res.errors++
                for anchordata in ad.anchors[link] {
                    eprintln(eline(fpath, anchordata.line, 0, 'multiple link targets of existing link (#${link})'))
                }
            }
        } else {
            found_error_warning = true
            res.errors++
            for brokenlink in linkdata {
                eprintln(eline(fpath, brokenlink.line, 0, 'no link target found for existing link [${brokenlink.lable}](#${link})'))
            }
        }
    }
    for link, anchor_lists in ad.anchors {
        if link !in checked_headlines {
            if anchor_lists.len > 1 {
                for anchor in anchor_lists {
                    line := match anchor {
                        Headline {
                            anchor.line
                        }
                        Anchor {
                            anchor.line
                        }
                    }
                    wprintln(wline(fpath, line, 0, 'multiple link target for non existing link (#${link})'))
                    found_error_warning = true
                    res.warnings++
                }
            }
        }
    }
    if found_error_warning {
        eprintln('') // fix suppressed last error output
    }
}

// based on a reference sample md doc
// https://github.com/aheissenberger/vlang-markdown-module/blob/master/test.md
fn create_ref_link(s string) string {
    mut result := ''
    for c in s.trim_space() {
        result += match c {
            `a`...`z`, `0`...`9` {
                c.ascii_str()
            }
            `A`...`Z` {
                c.ascii_str().to_lower()
            }
            ` `, `-` {
                '-'
            }
            `_` {
                '_'
            }
            else {
                if c > 127 { c.ascii_str() } else { '' }
            }
        }
    }
    return result
}

fn (mut f MDFile) debug() {
    for e in f.examples {
        eprintln('f.path: ${f.path} | example: ${e}')
    }
}

fn cmdexecute(cmd string) int {
    verbose_println(cmd)
    res := os.execute(cmd)
    if res.exit_code < 0 {
        return 1
    }
    if res.exit_code != 0 {
        eprint(res.output)
    }
    return res.exit_code
}

fn silent_cmdexecute(cmd string) int {
    verbose_println(cmd)
    res := os.execute(cmd)
    return res.exit_code
}

fn get_fmt_exit_code(vfile string, vexe string) int {
    return silent_cmdexecute('${os.quoted_path(vexe)} fmt -verify ${os.quoted_path(vfile)}')
}

fn (mut f MDFile) check_examples() CheckResult {
    mut errors := 0
    mut oks := 0
    recheck_all_examples: for e in f.examples {
        if e.command == 'ignore' {
            continue
        }
        if e.command == 'wip' {
            continue
        }
        fname := os.base(f.path).replace('.md', '_md')
        uid := rand.ulid()
        cfile := os.join_path(vcheckfolder, '${uid}.c')
        vfile := os.join_path(vcheckfolder, 'check_${fname}_example_${e.sline}__${e.eline}__${uid}.v')
        efile := os.join_path(vcheckfolder, 'check_${fname}_example_${e.sline}__${e.eline}__${uid}.exe')
        mut should_cleanup_vfile := true
        // eprintln('>>> checking example $vfile ...')
        vcontent := e.text.join('\n') + '\n'
        os.write_file(vfile, vcontent) or { panic(err) }
        mut acommands := e.command.split(' ')
        nofmt := 'nofmt' in acommands
        for command in acommands {
            f.progress('example from ${e.sline} to ${e.eline}, command: ${command}')
            fmt_res := if nofmt { 0 } else { get_fmt_exit_code(vfile, vexe) }
            match command {
                'compile' {
                    res := cmdexecute('${os.quoted_path(vexe)} -w -Wfatal-errors -o ${os.quoted_path(efile)} ${os.quoted_path(vfile)}')
                    if res != 0 || fmt_res != 0 {
                        if res != 0 {
                            eprintln(eline(f.path, e.sline, 0, 'example failed to compile'))
                        }
                        f.report_not_formatted_example_if_needed(e, fmt_res, vfile) or {
                            unsafe {
                                goto recheck_all_examples
                            }
                        }
                        eprintln(vcontent)
                        should_cleanup_vfile = false
                        errors++
                        continue
                    }
                    oks++
                }
                'cgen' {
                    res := cmdexecute('${os.quoted_path(vexe)} -w -Wfatal-errors -o ${os.quoted_path(cfile)} ${os.quoted_path(vfile)}')
                    if res != 0 || fmt_res != 0 {
                        if res != 0 {
                            eprintln(eline(f.path, e.sline, 0, 'example failed to generate C code'))
                        }
                        f.report_not_formatted_example_if_needed(e, fmt_res, vfile) or {
                            unsafe {
                                goto recheck_all_examples
                            }
                        }
                        eprintln(vcontent)
                        should_cleanup_vfile = false
                        errors++
                        continue
                    }
                    oks++
                }
                'globals' {
                    res := cmdexecute('${os.quoted_path(vexe)} -w -Wfatal-errors -enable-globals -o ${os.quoted_path(cfile)} ${os.quoted_path(vfile)}')
                    if res != 0 || fmt_res != 0 {
                        if res != 0 {
                            eprintln(eline(f.path, e.sline, 0, '`example failed to compile with -enable-globals'))
                        }
                        f.report_not_formatted_example_if_needed(e, fmt_res, vfile) or {
                            unsafe {
                                goto recheck_all_examples
                            }
                        }
                        eprintln(vcontent)
                        should_cleanup_vfile = false
                        errors++
                        continue
                    }
                    oks++
                }
                'live' {
                    res := cmdexecute('${os.quoted_path(vexe)} -w -Wfatal-errors -live -o ${os.quoted_path(cfile)} ${os.quoted_path(vfile)}')
                    if res != 0 || fmt_res != 0 {
                        if res != 0 {
                            eprintln(eline(f.path, e.sline, 0, 'example failed to compile with -live'))
                        }
                        f.report_not_formatted_example_if_needed(e, fmt_res, vfile) or {
                            unsafe {
                                goto recheck_all_examples
                            }
                        }
                        eprintln(vcontent)
                        should_cleanup_vfile = false
                        errors++
                        continue
                    }
                    oks++
                }
                'shared' {
                    res := cmdexecute('${os.quoted_path(vexe)} -w -Wfatal-errors -shared -o ${os.quoted_path(cfile)} ${os.quoted_path(vfile)}')
                    if res != 0 || fmt_res != 0 {
                        if res != 0 {
                            eprintln(eline(f.path, e.sline, 0, 'module example failed to compile with -shared'))
                        }
                        f.report_not_formatted_example_if_needed(e, fmt_res, vfile) or {
                            unsafe {
                                goto recheck_all_examples
                            }
                        }
                        eprintln(vcontent)
                        should_cleanup_vfile = false
                        errors++
                        continue
                    }
                    oks++
                }
                'failcompile' {
                    res := silent_cmdexecute('${os.quoted_path(vexe)} -w -Wfatal-errors -o ${os.quoted_path(cfile)} ${os.quoted_path(vfile)}')
                    if res == 0 || fmt_res != 0 {
                        if res == 0 {
                            eprintln(eline(f.path, e.sline, 0, '`failcompile` example compiled'))
                        }
                        f.report_not_formatted_example_if_needed(e, fmt_res, vfile) or {
                            unsafe {
                                goto recheck_all_examples
                            }
                        }
                        eprintln(vcontent)
                        should_cleanup_vfile = false
                        errors++
                        continue
                    }
                    oks++
                }
                'oksyntax' {
                    res := cmdexecute('${os.quoted_path(vexe)} -w -Wfatal-errors -check-syntax ${os.quoted_path(vfile)}')
                    if res != 0 || fmt_res != 0 {
                        if res != 0 {
                            eprintln(eline(f.path, e.sline, 0, '`oksyntax` example with invalid syntax'))
                        }
                        f.report_not_formatted_example_if_needed(e, fmt_res, vfile) or {
                            unsafe {
                                goto recheck_all_examples
                            }
                        }
                        eprintln(vcontent)
                        should_cleanup_vfile = false
                        errors++
                        continue
                    }
                    oks++
                }
                'okfmt' {
                    if fmt_res != 0 {
                        f.report_not_formatted_example_if_needed(e, fmt_res, vfile) or {
                            unsafe {
                                goto recheck_all_examples
                            }
                        }
                        eprintln(vcontent)
                        should_cleanup_vfile = false
                        errors++
                        continue
                    }
                    oks++
                }
                'badsyntax' {
                    res := silent_cmdexecute('${os.quoted_path(vexe)} -w -Wfatal-errors -check-syntax ${os.quoted_path(vfile)}')
                    if res == 0 {
                        eprintln(eline(f.path, e.sline, 0, '`badsyntax` example can be parsed fine'))
                        eprintln(vcontent)
                        should_cleanup_vfile = false
                        errors++
                        continue
                    }
                    oks++
                }
                'nofmt' {}
                // mark the example as playable inside docs
                'play' {}
                // same as play, but run example as a test
                'play-test' {}
                // when ```vmod
                'mod' {}
                else {
                    eprintln(eline(f.path, e.sline, 0, 'unrecognized command: "${command}", use one of: wip/ignore/compile/failcompile/okfmt/nofmt/oksyntax/badsyntax/cgen/globals/live/shared'))
                    should_cleanup_vfile = false
                    errors++
                }
            }
        }
        os.rm(cfile) or {}
        os.rm(efile) or {}
        if should_cleanup_vfile {
            os.rm(vfile) or { panic(err) }
        }
    }
    return CheckResult{
        errors: errors
        oks: oks
    }
}

fn verbose_println(message string) {
    if is_verbose {
        println(message)
    }
}

fn clear_previous_line() {
    if is_verbose {
        return
    }
    term.clear_previous_line()
}

fn (mut f MDFile) report_not_formatted_example_if_needed(e VCodeExample, fmt_res int, vfile string) ! {
    if fmt_res == 0 {
        return
    }
    eprintln(eline(f.path, e.sline, 0, 'example is not formatted'))
    if !should_autofix {
        return
    }
    f.autofix_example(e, vfile) or {
        if err is ExampleWasRewritten {
            eprintln('>> f.path: ${f.path} | example from ${e.sline} to ${e.eline} was re-formated by vfmt')
            return err
        }
        eprintln('>> f.path: ${f.path} | encountered error while autofixing the example: ${err}')
    }
}

struct ExampleWasRewritten {
    Error
}

fn (mut f MDFile) autofix_example(e VCodeExample, vfile string) ! {
    eprintln('>>> AUTOFIXING f.path: ${f.path} | e.sline: ${e.sline} | vfile: ${vfile}')
    res := cmdexecute('${os.quoted_path(vexe)} fmt -w ${os.quoted_path(vfile)}')
    if res != 0 {
        return error('could not autoformat the example')
    }
    formatted_content_lines := os.read_lines(vfile) or { return }
    mut new_lines := []string{}
    new_lines << f.lines#[0..e.sline + 1]
    new_lines << formatted_content_lines
    new_lines << f.lines#[e.eline..]
    f.update_examples(new_lines)!
    os.rm(vfile) or {}
    f.examples = f.examples.filter(it.sline >= e.sline)
    return ExampleWasRewritten{}
}

fn (mut f MDFile) update_examples(new_lines []string) ! {
    os.write_file(f.path, new_lines.join('\n'))!
    f.lines = new_lines
    f.examples = []
    f.current = VCodeExample{}
    f.state = .markdown
    for j, line in f.lines {
        f.parse_line(j, line)
    }
}