#include "ShellHighlighter.h"
#include "Buffer.h"
#include <cctype>

namespace kte {

static void push(std::vector<HighlightSpan> &out, int a, int b, TokenKind k){ if (b>a) out.push_back({a,b,k}); }

void ShellHighlighter::HighlightLine(const Buffer &buf, int row, std::vector<HighlightSpan> &out) const
{
    const auto &rows = buf.Rows();
    if (row < 0 || static_cast<std::size_t>(row) >= rows.size()) return;
    std::string s = static_cast<std::string>(rows[static_cast<std::size_t>(row)]);
    int n = static_cast<int>(s.size());
    int i = 0;
    // if first non-space is '#', whole line is comment
    int bol = 0; while (bol < n && (s[bol]==' '||s[bol]=='\t')) ++bol;
    if (bol < n && s[bol] == '#') { push(out, bol, n, TokenKind::Comment); if (bol>0) push(out,0,bol,TokenKind::Whitespace); return; }
    while (i < n) {
        char c = s[i];
        if (c == ' ' || c == '\t') { int j=i+1; while (j<n && (s[j]==' '||s[j]=='\t')) ++j; push(out,i,j,TokenKind::Whitespace); i=j; continue; }
        if (c == '#') { push(out, i, n, TokenKind::Comment); break; }
        if (c == '\'' || c == '"') {
            char q = c; int j = i+1; bool esc=false; while (j<n) { char d=s[j++]; if (q=='"') { if (esc) {esc=false; continue;} if (d=='\\'){esc=true; continue;} if (d=='"') break; } else { if (d=='\'') break; } }
            push(out,i,j,TokenKind::String); i=j; continue;
        }
        // simple keywords
        if (std::isalpha(static_cast<unsigned char>(c))) {
            int j=i+1; while (j<n && (std::isalnum(static_cast<unsigned char>(s[j]))||s[j]=='_')) ++j; std::string id=s.substr(i,j-i);
            static const char* kws[] = {"if","then","fi","for","in","do","done","case","esac","while","function","elif","else"};
            bool kw=false; for (auto k: kws) if (id==k) { kw=true; break; }
            push(out,i,j, kw?TokenKind::Keyword:TokenKind::Identifier); i=j; continue;
        }
        if (std::ispunct(static_cast<unsigned char>(c))) {
            TokenKind k = TokenKind::Operator;
            if (c=='('||c==')'||c=='{'||c=='}'||c==','||c==';') k=TokenKind::Punctuation;
            push(out,i,i+1,k); ++i; continue;
        }
        push(out,i,i+1,TokenKind::Default); ++i;
    }
}

} // namespace kte