#!/usr/bin/perl

package IkiWiki;

use warnings;
use strict;
use IkiWiki;
use Encode;

my %backlinks;
my $backlinks_calculated=0;

sub calculate_backlinks () { #{{{
    return if $backlinks_calculated;
    %backlinks=();
    foreach my $page (keys %links) {
        foreach my $link (@{$links{$page}}) {
            my $bestlink=bestlink($page, $link);
            if (length $bestlink && $bestlink ne $page) {
                $backlinks{$bestlink}{$page}=1;
            }
        }
    }
    $backlinks_calculated=1;
} #}}}

sub backlinks ($) { #{{{
    my $page=shift;

    calculate_backlinks();

    my @links;
    foreach my $p (keys %{$backlinks{$page}}) {
        my $href=urlto($p, $page);
                
        # Trim common dir prefixes from both pages.
        my $p_trimmed=$p;
        my $page_trimmed=$page;
        my $dir;
        1 while (($dir)=$page_trimmed=~m!^([^/]+/)!) &&
                defined $dir &&
                $p_trimmed=~s/^\Q$dir\E// &&
                $page_trimmed=~s/^\Q$dir\E//;
                   
        push @links, { url => $href, page => pagetitle($p_trimmed) };
    }
    return @links;
} #}}}

sub parentlinks ($) { #{{{
    my $page=shift;
    
    my @ret;
    my $pagelink="";
    my $path="";
    my $title=$config{wikiname};
    
    foreach my $dir (split("/", $page)) {
        next if $dir eq 'index';
        push @ret, { url => urlto($path, $page), page => $title };
        $path.="/".$dir;
        $title=pagetitle($dir);
    }
    return @ret;
} #}}}

sub genpage ($$) { #{{{
    my $page=shift;
    my $content=shift;

    my $templatefile;
    run_hooks(templatefile => sub {
        return if defined $templatefile;
        my $file=shift->(page => $page);
        if (defined $file && defined template_file($file)) {
            $templatefile=$file;
        }
    });
    my $template=template(defined $templatefile ? $templatefile : 'page.tmpl', blind_cache => 1);
    my $actions=0;

    if (length $config{cgiurl}) {
        $template->param(editurl => cgiurl(do => "edit", page => pagetitle($page, 1)));
        $template->param(prefsurl => cgiurl(do => "prefs"));
        $actions++;
    }
        
    if (length $config{historyurl}) {
        my $u=$config{historyurl};
        $u=~s/\[\[file\]\]/$pagesources{$page}/g;
        $template->param(historyurl => $u);
        $actions++;
    }
    if ($config{discussion}) {
        my $discussionlink=gettext("discussion");
        if ($page !~ /.*\/\Q$discussionlink\E$/ &&
           (length $config{cgiurl} ||
            exists $links{$page."/".$discussionlink})) {
            $template->param(discussionlink => htmllink($page, $page, gettext("Discussion"), noimageinline => 1, forcesubpage => 1));
            $actions++;
        }
    }

    if ($actions) {
        $template->param(have_actions => 1);
    }

    my @backlinks=sort { $a->{page} cmp $b->{page} } backlinks($page);
    my ($backlinks, $more_backlinks);
    if (@backlinks <= $config{numbacklinks} || ! $config{numbacklinks}) {
        $backlinks=\@backlinks;
        $more_backlinks=[];
    }
    else {
        $backlinks=[@backlinks[0..$config{numbacklinks}-1]];
        $more_backlinks=[@backlinks[$config{numbacklinks}..$#backlinks]];
    }

    $template->param(
        title => $page eq 'index' 
            ? $config{wikiname} 
            : pagetitle(basename($page)),
        wikiname => $config{wikiname},
        parentlinks => [parentlinks($page)],
        content => $content,
        backlinks => $backlinks,
        more_backlinks => $more_backlinks,
        mtime => displaytime($pagemtime{$page}),
        ctime => displaytime($pagectime{$page}),
        baseurl => baseurl($page),
    );

    run_hooks(pagetemplate => sub {
        shift->(page => $page, destpage => $page, template => $template);
    });
    
    $content=$template->output;

    run_hooks(format => sub {
        $content=shift->(
            page => $page,
            content => $content,
        );
    });

    return $content;
} #}}}

sub mtime ($) { #{{{
    my $file=shift;
    
    return (stat($file))[9];
} #}}}

sub scan ($) { #{{{
    my $file=shift;

    my $type=pagetype($file);
    if (defined $type) {
        my $srcfile=srcfile($file);
        my $content=readfile($srcfile);
        my $page=pagename($file);
        will_render($page, htmlpage($page), 1);

        # Always needs to be done, since filters might add links
        # to the content.
        $content=filter($page, $page, $content);
    
        if ($config{discussion}) {
            # Discussion links are a special case since they're
            # not in the text of the page, but on its template.
            $links{$page}=[ $page."/".gettext("discussion") ];
        }
        else {
            $links{$page}=[];
        }

        run_hooks(scan => sub {
            shift->(
                page => $page,
                content => $content,
            );
        });

        # Preprocess in scan-only mode.
        preprocess($page, $page, $content, 1);
    }
    else {
        will_render($file, $file, 1);
    }
} #}}}

sub render ($) { #{{{
    my $file=shift;
    
    my $type=pagetype($file);
    my $srcfile=srcfile($file);
    if (defined $type) {
        my $page=pagename($file);
        delete $depends{$page};
        will_render($page, htmlpage($page), 1);
        return if $type=~/^_/;
        
        my $content=htmlize($page, $type,
            linkify($page, $page,
            preprocess($page, $page,
            filter($page, $page,
            readfile($srcfile)))));
        
        my $output=htmlpage($page);
        writefile($output, $config{destdir}, genpage($page, $content));
    }
    else {
        my $srcfd=readfile($srcfile, 1, 1);
        delete $depends{$file};
        will_render($file, $file, 1);
        writefile($file, $config{destdir}, undef, 1, sub {
            my $destfd=shift;
            my $cleanup=shift;

            my $blksize = 16384;
            my ($len, $buf, $written);
            while ($len = sysread $srcfd, $buf, $blksize) {
                if (! defined $len) {
                    next if $! =~ /^Interrupted/;
                    error("failed to read $srcfile: $!", $cleanup);
                }
                my $offset = 0;