#include "section_link.h"
#include "error.h"
#include "locator.h"
#include "util.h"
#include <regex>
#include <sstream>

std::string normalize_section_title(const std::string& s)
{
    static const std::regex number_rgx(R"(<span class="sectionnumber">.*?</span>)");
    static const std::regex tag_rgx("<[^>]*>");
    static const std::regex tex_command_rgx(R"(\\[A-Za-z@]+\*?)");
    static const std::regex space_rgx(R"(\s+)");
    std::string t = std::regex_replace(s, number_rgx, "");
    t = std::regex_replace(t, tag_rgx, "");
    t = std::regex_replace(t, tex_command_rgx, "");
    t = string_replace(string_replace(t, "{", ""), "}", "");
    t = std::regex_replace(t, space_rgx, " ");
    return trim(t);
}

Section_target resolve_section_target(
    const std::vector<Section_target>& table, const std::string& title,
    const std::string& file, const std::string& where,
    const std::vector<std::string>& files)
{
    const std::string wanted = normalize_section_title(title);
    const std::string in = file.empty() ? where : file;     // the one file searched
    const std::string in_name = in.empty() ? std::string("the document's :text") : in;
    std::stringstream ss {};
    ss << "In " << (where.empty() ? std::string("the document's :text") : where)
       << ", a :section link names the heading " << q_(title);
    if (!file.empty()) {
        bool known = false;
        for (const auto& f : files) known = known || f == file;
        if (!known) {
            ss << " in " << file << ", but the document has no file " << file
               << " (its files are " << join(files, ", ") << ").";
            throw Argument_error(ss.str(), Locator::none());
        }
    }
    std::vector<const Section_target*> hits {};
    for (const auto& t : table) {
        if (t.basename == in && t.title == wanted) hits.push_back(&t);
    }
    if (hits.size() == 1) return *hits[0];
    if (hits.empty()) {
        ss << ", which " << in_name << " does not have"
           << (file.empty() ? " (a section in another file needs its basename as the value of :section)." : ".");
    } else {
        ss << ", which " << in_name << " has " << hits.size()
           << " times: give one of them an :id and link to that.";
    }
    throw Argument_error(ss.str(), Locator::none());
}