import option;
import str;
import io::reader_util;

import common::config;

export test_props;
export load_props;
export is_test_ignored;

type test_props = {
    // Lines that should be expected, in order, on standard out
    error_patterns: [str],
    // Extra flags to pass to the compiler
    compile_flags: option<str>,
    // If present, the name of a file that this test should match when
    // pretty-printed
    pp_exact: option<str>,
    // Modules from aux directory that should be compiled
    aux_builds: [str],
    // Environment settings to use during execution
    exec_env: [(str,str)]
};

// Load any test directives embedded in the file
fn load_props(testfile: str) -> test_props {
    let mut error_patterns = [];
    let mut aux_builds = [];
    let mut exec_env = [];
    let mut compile_flags = option::none;
    let mut pp_exact = option::none;
    for iter_header(testfile) {|ln|
        alt parse_error_pattern(ln) {
          option::some(ep) { error_patterns += [ep]; }
          option::none { }
        };

        if option::is_none(compile_flags) {
            compile_flags = parse_compile_flags(ln);
        }

        if option::is_none(pp_exact) {
            pp_exact = parse_pp_exact(ln, testfile);
        }

        option::iter(parse_aux_build(ln)) {|ab|
            aux_builds += [ab];
        }

        option::iter(parse_exec_env(ln)) {|ee|
            exec_env += [ee];
        }
    };
    ret {
        error_patterns: error_patterns,
        compile_flags: compile_flags,
        pp_exact: pp_exact,
        aux_builds: aux_builds,
        exec_env: exec_env
    };
}

fn is_test_ignored(config: config, testfile: str) -> bool {
    let mut found = false;
    for iter_header(testfile) {|ln|
        if parse_name_directive(ln, "xfail-test") { ret true; }
        if parse_name_directive(ln, xfail_target()) { ret true; }
        if config.mode == common::mode_pretty &&
           parse_name_directive(ln, "xfail-pretty") { ret true; }
    };
    ret found;

    fn xfail_target() -> str {
        "xfail-" + os::sysname()
    }
}

fn iter_header(testfile: str, it: fn(str) -> bool) -> bool {
    let rdr = result::get(io::file_reader(testfile));
    while !rdr.eof() {
        let ln = rdr.read_line();

        // Assume that any directives will be found before the first
        // module or function. This doesn't seem to be an optimization
        // with a warm page cache. Maybe with a cold one.
        if str::starts_with(ln, "fn")
            || str::starts_with(ln, "mod") {
            ret false;
        } else { if !(it(ln)) { ret false; } }
    }
    ret true;
}

fn parse_error_pattern(line: str) -> option<str> {
    parse_name_value_directive(line, "error-pattern")
}

fn parse_aux_build(line: str) -> option<str> {
    parse_name_value_directive(line, "aux-build")
}

fn parse_compile_flags(line: str) -> option<str> {
    parse_name_value_directive(line, "compile-flags")
}

fn parse_exec_env(line: str) -> option<(str, str)> {
    parse_name_value_directive(line, "exec-env").map {|nv|
        // nv is either FOO or FOO=BAR
        let strs = str::splitn_char(nv, '=', 1u);
        alt strs.len() {
          1u { (strs[0], "") }
          2u { (strs[0], strs[1]) }
          n { fail #fmt["Expected 1 or 2 strings, not %u", n]; }
        }
    }
}

fn parse_pp_exact(line: str, testfile: str) -> option<str> {
    alt parse_name_value_directive(line, "pp-exact") {
      option::some(s) { option::some(s) }
      option::none {
        if parse_name_directive(line, "pp-exact") {
            option::some(path::basename(testfile))
        } else {
            option::none
        }
      }
    }
}

fn parse_name_directive(line: str, directive: str) -> bool {
    str::contains(line, directive)
}

fn parse_name_value_directive(line: str,
                              directive: str) -> option<str> unsafe {
    let keycolon = directive + ":";
    alt str::find_str(line, keycolon) {
        option::some(colon) {
            let value = str::slice(line, colon + str::len(keycolon),
                                   str::len(line));
            #debug("%s: %s", directive,  value);
            option::some(value)
        }
        option::none { option::none }
    }
}