// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use collections::HashSet;
use std::{str, io};
use std::strbuf::StrBuf;

use getopts;
use testing;

use html::escape::Escape;
use html::markdown::{MarkdownWithToc, find_testable_code, reset_headers};
use test::Collector;

fn load_string(input: &Path) -> io::IoResult<Option<~str>> {
    let mut f = try!(io::File::open(input));
    let d = try!(f.read_to_end());
    Ok(str::from_utf8(d.as_slice()).map(|s| s.to_owned()))
}
macro_rules! load_or_return {
    ($input: expr, $cant_read: expr, $not_utf8: expr) => {
        {
            let input = Path::new($input);
            match load_string(&input) {
                Err(e) => {
                    let _ = writeln!(&mut io::stderr(),
                                     "error reading `{}`: {}", input.display(), e);
                    return $cant_read;
                }
                Ok(None) => {
                    let _ = writeln!(&mut io::stderr(),
                                     "error reading `{}`: not UTF-8", input.display());
                    return $not_utf8;
                }
                Ok(Some(s)) => s
            }
        }
    }
}

/// Separate any lines at the start of the file that begin with `%`.
fn extract_leading_metadata<'a>(s: &'a str) -> (Vec<&'a str>, &'a str) {
    let mut metadata = Vec::new();
    for line in s.lines() {
        if line.starts_with("%") {
            // remove %<whitespace>
            metadata.push(line.slice_from(1).trim_left())
        } else {
            let line_start_byte = s.subslice_offset(line);
            return (metadata, s.slice_from(line_start_byte));
        }
    }
    // if we're here, then all lines were metadata % lines.
    (metadata, "")
}

fn load_external_files(names: &[~str]) -> Option<~str> {
    let mut out = StrBuf::new();
    for name in names.iter() {
        out.push_str(load_or_return!(name.as_slice(), None, None));
        out.push_char('\n');
    }
    Some(out.into_owned())
}

/// Render `input` (e.g. "foo.md") into an HTML file in `output`
/// (e.g. output = "bar" => "bar/foo.html").
pub fn render(input: &str, mut output: Path, matches: &getopts::Matches) -> int {
    let input_p = Path::new(input);
    output.push(input_p.filestem().unwrap());
    output.set_extension("html");

    let mut css = StrBuf::new();
    for name in matches.opt_strs("markdown-css").iter() {
        let s = format!("<link rel=\"stylesheet\" type=\"text/css\" href=\"{}\">\n", name);
        css.push_str(s)
    }

    let input_str = load_or_return!(input, 1, 2);

    let (in_header, before_content, after_content) =
        match (load_external_files(matches.opt_strs("markdown-in-header")
                                          .as_slice()),
               load_external_files(matches.opt_strs("markdown-before-content")
                                          .as_slice()),
               load_external_files(matches.opt_strs("markdown-after-content")
                                          .as_slice())) {
        (Some(a), Some(b), Some(c)) => (a,b,c),
        _ => return 3
    };

    let mut out = match io::File::create(&output) {
        Err(e) => {
            let _ = writeln!(&mut io::stderr(),
                             "error opening `{}` for writing: {}",
                             output.display(), e);
            return 4;
        }
        Ok(f) => f
    };

    let (metadata, text) = extract_leading_metadata(input_str);
    if metadata.len() == 0 {
        let _ = writeln!(&mut io::stderr(),
                         "invalid markdown file: expecting initial line with `% ...TITLE...`");
        return 5;
    }
    let title = metadata.get(0).as_slice();

    reset_headers();

    let err = write!(
        &mut out,
        r#"<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <meta name="generator" content="rustdoc">
    <title>{title}</title>

    {css}
    {in_header}
</head>
<body>
    <!--[if lte IE 8]>
    <div class="warning">
        This old browser is unsupported and will most likely display funky
        things.
    </div>
    <![endif]-->

    {before_content}
    <h1 class="title">{title}</h1>
    {text}
    {after_content}
</body>
</html>"#,
        title = Escape(title),
        css = css,
        in_header = in_header,
        before_content = before_content,
        text = MarkdownWithToc(text),
        after_content = after_content);

    match err {
        Err(e) => {
            let _ = writeln!(&mut io::stderr(),
                             "error writing to `{}`: {}",
                             output.display(), e);
            6
        }
        Ok(_) => 0
    }
}

/// Run any tests/code examples in the markdown file `input`.
pub fn test(input: &str, libs: HashSet<Path>, mut test_args: ~[~str]) -> int {
    let input_str = load_or_return!(input, 1, 2);

    let mut collector = Collector::new(input.to_owned(), libs, true, true);
    find_testable_code(input_str, &mut collector);
    test_args.unshift(~"rustdoctest");
    testing::test_main(test_args, collector.tests);
    0
}