module builtin

// panic_debug private function that V uses for panics, -cg/-g is passed
// recent versions of tcc print nicer backtraces automatically
// Note: the duplication here is because tcc_backtrace should be called directly
// inside the panic functions.
@[noreturn]
fn panic_debug(line_no int, file string, mod string, fn_name string, s string) {
    // Note: the order here is important for a stabler test output
    // module is less likely to change than function, etc...
    // During edits, the line number will change most frequently,
    // so it is last
    $if freestanding {
        bare_panic(s)
    } $else {
        // vfmt off
        // Note: be carefull to not allocate here, avoid string interpolation
        flush_stdout()
        eprintln('================ V panic ================')
        eprint('   module: '); eprintln(mod)
        eprint(' function: '); eprint(fn_name); eprintln('()')
        eprint('  message: '); eprintln(s)
        eprint('     file: '); eprint(file); eprint(':');
        C.fprintf(C.stderr, c'%d\n', line_no)
        eprint('   v hash: '); eprintln(vcurrent_hash())
        $if !vinix {
            eprint('      pid: '); C.fprintf(C.stderr, c'%p\n', voidptr(v_getpid()))
            eprint('      tid: '); C.fprintf(C.stderr, c'%p\n', voidptr(v_gettid()))
        }
        eprintln('=========================================')
        flush_stdout()
        // vfmt on
        $if exit_after_panic_message ? {
            C.exit(1)
        } $else $if no_backtrace ? {
            C.exit(1)
        } $else {
            $if tinyc {
                $if panics_break_into_debugger ? {
                    break_if_debugger_attached()
                } $else {
                    C.tcc_backtrace(c'Backtrace')
                }
                C.exit(1)
            }
            $if use_libbacktrace ? {
                $if openbsd {
                    print_backtrace_skipping_top_frames(1)
                } $else {
                    eprint_libbacktrace(1)
                }
            } $else {
                print_backtrace_skipping_top_frames(1)
            }
            $if panics_break_into_debugger ? {
                break_if_debugger_attached()
            }
            C.exit(1)
        }
    }
    C.exit(1)
    for {}
}

// panic_option_not_set is called by V, when you use option error propagation in your main function.
// It ends the program with a panic.
@[noreturn]
pub fn panic_option_not_set(s string) {
    panic('option not set (' + s + ')')
}

// panic_result_not_set is called by V, when you use result error propagation in your main function
// It ends the program with a panic.
@[noreturn]
pub fn panic_result_not_set(s string) {
    panic('result not set (' + s + ')')
}

// panic prints a nice error message, then exits the process with exit code of 1.
// It also shows a backtrace on most platforms.
@[noreturn]
pub fn panic(s string) {
    // Note: be careful to not use string interpolation here:
    $if freestanding {
        bare_panic(s)
    } $else {
        // vfmt off
        flush_stdout()
        eprint('V panic: ')
        eprintln(s)
        eprint(' v hash: ')
        eprintln(vcurrent_hash())
        $if !vinix {
            eprint('    pid: '); C.fprintf(C.stderr, c'%p\n', voidptr(v_getpid()))
            eprint('    tid: '); C.fprintf(C.stderr, c'%p\n', voidptr(v_gettid()))
        }
        flush_stdout()
        // vfmt on
        $if exit_after_panic_message ? {
            C.exit(1)
        } $else $if no_backtrace ? {
            C.exit(1)
        } $else {
            $if tinyc {
                $if panics_break_into_debugger ? {
                    break_if_debugger_attached()
                } $else {
                    C.tcc_backtrace(c'Backtrace')
                }
                C.exit(1)
            }
            $if use_libbacktrace ? {
                $if openbsd {
                    print_backtrace_skipping_top_frames(1)
                } $else {
                    eprint_libbacktrace(1)
                }
            } $else {
                print_backtrace_skipping_top_frames(1)
            }
            $if panics_break_into_debugger ? {
                break_if_debugger_attached()
            }
            C.exit(1)
        }
    }
    C.exit(1)
    for {}
}

// return a C-API error message matching to `errnum`
pub fn c_error_number_str(errnum int) string {
    mut err_msg := ''
    $if freestanding {
        err_msg = 'error ' + errnum.str()
    } $else {
        $if !vinix {
            c_msg := C.strerror(errnum)
            err_msg = string{
                str:    &u8(c_msg)
                len:    int(unsafe { C.strlen(c_msg) })
                is_lit: 1
            }
        }
    }
    return err_msg
}

// panic_n prints an error message, followed by the given number, then exits the process with exit code of 1.
@[noreturn]
pub fn panic_n(s string, number1 i64) {
    panic(s + impl_i64_to_string(number1))
}

// panic_n2 prints an error message, followed by the given numbers, then exits the process with exit code of 1.
@[noreturn]
pub fn panic_n2(s string, number1 i64, number2 i64) {
    panic(s + impl_i64_to_string(number1) + ', ' + impl_i64_to_string(number2))
}

// panic_n3 prints an error message, followed by the given numbers, then exits the process with exit code of 1.
@[noreturn]
fn panic_n3(s string, number1 i64, number2 i64, number3 i64) {
    panic(s + impl_i64_to_string(number1) + ', ' + impl_i64_to_string(number2) + ', ' +
        impl_i64_to_string(number3))
}

// panic with a C-API error message matching `errnum`
@[noreturn]
pub fn panic_error_number(basestr string, errnum int) {
    panic(basestr + c_error_number_str(errnum))
}