// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module builder

import os
import v.pref
import v.util
import v.vmod

pub type FnBackend = fn (mut b Builder)

// should_find_windows_host_c_compiler reports whether Windows host compiler probing is needed.
pub fn should_find_windows_host_c_compiler(pref_ &pref.Preferences) bool {
    return pref_.backend == .c && pref_.os == .windows && !pref_.output_cross_c
}

pub fn compile(command string, pref_ &pref.Preferences, backend_cb FnBackend) {
    check_if_input_file_exists(pref_)
    check_if_output_folder_is_writable(pref_)
    $if windows {
        if should_find_windows_host_c_compiler(pref_) {
            // Resolve the effective Windows C compiler before builder initialization.
            mut probe := Builder{
                pref: unsafe { pref_ }
            }
            probe.find_win_cc() or {}
        }
    }
    mut pref_ref := unsafe { pref_ }
    pref_ref.ccompiler_type = resolve_ccompiler_type(pref_ref.ccompiler, pref_ref.ccompiler_type)
    // Construct the V object from command line arguments
    mut b := new_builder(pref_)
    if b.should_rebuild() {
        b.rebuild(backend_cb)
    }
    b.exit_on_invalid_syntax()
    // running does not require the parsers anymore
    unsafe { b.myfree() }
    b.run_compiled_executable_and_exit()
}

fn check_if_input_file_exists(pref_ &pref.Preferences) {
    if pref_.path == '' || pref_.path == '-' {
        return
    }
    if pref_.path.ends_with('.v') || pref_.path.ends_with('.vsh') || pref_.path.ends_with('.vv') {
        if !os.exists(pref_.path) {
            verror("${pref_.path} doesn't exist")
        }
    }
}

fn check_if_output_folder_is_writable(pref_ &pref.Preferences) {
    if pref_.should_output_to_stdout() || pref_.check_only || pref_.only_check_syntax
        || pref_.backend == .interpret {
        return
    }
    odir := os.dir(pref_.out_name)
    // When pref.out_name is just the name of an executable, i.e. `./v -o executable main.v`
    // without a folder component, just use the current folder instead:
    mut output_folder := odir
    if odir.len == pref_.out_name.len {
        output_folder = os.getwd()
    }
    os.mkdir_all(output_folder) or { verror(err.msg()) }
    os.ensure_folder_is_writable(output_folder) or {
        // An early error here, is better than an unclear C error later:
        verror(err.msg())
    }
}

// Temporary, will be done by -autofree
@[unsafe]
fn (mut b Builder) myfree() {
    // for file in b.parsed_files {
    // }
    unsafe { b.parsed_files.free() }
    util.free_caches()
}

fn (b &Builder) exit_on_invalid_syntax() {
    util.free_caches()
    // V should exit with an exit code of 1, when there are errors,
    // even when -silent is passed in combination to -check-syntax:
    if b.pref.only_check_syntax {
        for pf in b.parsed_files {
            if pf.errors.len > 0 {
                exit(1)
            }
        }
        if b.checker.nr_errors > 0 {
            exit(1)
        }
    }
}

fn (mut b Builder) run_compiled_executable_and_exit() {
    if b.pref.backend == .interpret {
        // the interpreted code has already ran
        return
    }
    if b.pref.skip_running {
        return
    }
    if b.pref.only_check_syntax || b.pref.check_only {
        return
    }
    if b.pref.should_output_to_stdout() {
        return
    }
    if b.pref.os == .ios {
        panic('Running iOS apps is not supported yet.')
    }
    if !(b.pref.is_test || b.pref.is_run || b.pref.is_crun) {
        exit(0)
    }
    mut compiled_file := b.pref.out_name
    if b.pref.backend == .wasm && !compiled_file.ends_with('.wasm') {
        compiled_file += '.wasm'
    }
    if b.pref.backend == .c && b.pref.os == .windows && !compiled_file.ends_with('.exe') {
        compiled_file += '.exe'
    }
    compiled_file = os.real_path(compiled_file)

    mut run_args := []string{cap: b.pref.run_args.len + 1}

    run_file := if b.pref.backend.is_js() {
        node_basename := $if windows { 'node.exe' } $else { 'node' }
        os.find_abs_path_of_executable(node_basename) or {
            panic('Could not find `${node_basename}` in system path. Do you have Node.js installed?')
        }
    } else if b.pref.backend == .wasm {
        mut actual_run := ['wasmer', 'wasmtime', 'wavm', 'wasm3', 'iwasm']
        mut actual_rf := ''

        // -autofree bug
        // error: cannot convert 'struct string' to 'struct _option_string'
        // mut actual_rf := ?string(none)

        for runtime in actual_run {
            basename := $if windows { runtime + '.exe' } $else { runtime }

            if rf := os.find_abs_path_of_executable(basename) {
                if basename == 'wavm' {
                    run_args << 'run'
                }
                actual_rf = rf
                break
            }
        }

        if actual_rf == '' {
            panic('Could not find `wasmer`, `wasmtime`, `wavm`, `wasm3` or `ìwasm` in system path. Do you have any installed?')
        }

        actual_rf
    } else {
        compiled_file
    }
    if b.pref.backend.is_js() || b.pref.backend == .wasm {
        run_args << compiled_file
    }
    run_args << b.pref.run_args

    if b.pref.is_verbose {
        println('running ${run_file} with arguments ${run_args.join(' ')}')
    }
    if b.pref.is_shared {
        verror('can not run shared library ${run_file}')
    }
    mut ret := 0
    if b.pref.use_os_system_to_run {
        mut command_to_run := os.quoted_path(run_file)
        if run_args.len > 0 {
            command_to_run += ' ' + util.args_quote_paths(run_args)
        }
        ret = os.system(command_to_run)
        // eprintln('> ret: ${ret:5} | command_to_run: ${command_to_run}')
    } else {
        mut run_process := os.new_process(run_file)
        run_process.set_args(run_args)
        // Ignore sigint and sigquit while running the compiled file,
        // so ^C doesn't prevent v from deleting the compiled file.
        // See also https://git.musl-libc.org/cgit/musl/tree/src/process/system.c
        prev_int_handler := os.signal_opt(.int, eshcb) or { serror('set .int', err) }
        mut prev_quit_handler := os.SignalHandler(eshcb)
        $if !windows { // There's no sigquit on windows
            prev_quit_handler = os.signal_opt(.quit, eshcb) or { serror('set .quit', err) }
        }
        run_process.wait()
        os.signal_opt(.int, prev_int_handler) or { serror('restore .int', err) }
        $if !windows {
            os.signal_opt(.quit, prev_quit_handler) or { serror('restore .quit', err) }
        }
        ret = run_process.code
        if run_process.err != '' {
            eprintln(run_process.err)
        }
        run_process.close()
    }
    b.cleanup_run_executable_after_exit(compiled_file)
    exit(ret)
}

fn eshcb(_ os.Signal) {
}

@[noreturn]
fn serror(reason string, e IError) {
    eprintln('could not ${reason} handler')
    panic(e.msg())
}

fn (mut v Builder) cleanup_run_executable_after_exit(exefile string) {
    if v.pref.is_crun {
        return
    }
    if v.pref.reuse_tmpc {
        v.pref.vrun_elog('keeping executable: ${exefile} , because -keepc was passed')
        return
    }
    if !v.executable_exists {
        v.pref.vrun_elog('remove run executable: ${exefile}')
        os.rm(exefile) or {}
    }
}

// 'strings' => 'VROOT/vlib/strings'
// 'installed_mod' => '~/.vmodules/installed_mod'
// 'local_mod' => '/path/to/current/dir/local_mod'
pub fn (mut v Builder) set_module_lookup_paths() {
    // Module search order:
    // 0) V test files are very commonly located right inside the folder of the
    // module, which they test. Adding the parent folder of the module folder
    // with the _test.v files, *guarantees* that the tested module can be found
    // without needing to set custom options/flags.
    // 1) search in the *same* directory, as the compiled final v program source
    // (i.e. the . in `v .` or file.v in `v file.v`)
    // 2) search in the modules/ in the same directory.
    // 3) search in the provided paths
    // By default, these are what (3) contains:
    // 3.1) search in vlib/
    // 3.2) search in ~/.vmodules/ (i.e. modules installed with vpm)
    lookup_root := v.module_lookup_root()
    v.module_search_paths = []
    if v.pref.is_test {
        v.module_search_paths << os.dir(v.compiled_dir) // pdir of _test.v
    }
    v.module_search_paths << lookup_root
    x := os.join_path(lookup_root, 'modules')
    if v.pref.is_verbose {
        println('x: "${x}"')
    }

    if source_root := source_root_from_vmod_root(lookup_root) {
        source_modules := os.join_path(source_root, 'modules')
        if source_modules !in v.module_search_paths && os.exists(source_modules) {
            v.module_search_paths << source_modules
        }
    }
    if os.exists(os.join_path(lookup_root, 'modules')) {
        v.module_search_paths << os.join_path(lookup_root, 'modules')
    }

    v.module_search_paths << v.pref.lookup_path
    if v.pref.is_verbose {
        v.log('v.module_search_paths:')
        println(v.module_search_paths)
    }
}

fn (v &Builder) module_lookup_root() string {
    // If `compiled_dir` is the base_url-configured source folder, treat the
    // enclosing module folder as the lookup root so sibling `modules/` resolves.
    mut mcache := vmod.get_cache()
    vmod_file_location := mcache.get_by_folder(v.compiled_dir)
    if vmod_file_location.vmod_file != '' && vmod_file_location.vmod_folder != v.compiled_dir {
        if source_root := source_root_from_vmod_root(vmod_file_location.vmod_folder) {
            if os.real_path(source_root) == v.compiled_dir {
                return vmod_file_location.vmod_folder
            }
        }
    }
    return v.compiled_dir
}

pub fn (v Builder) get_builtin_files() []string {
    if v.pref.no_builtin {
        v.log('v.pref.no_builtin is true, get_builtin_files == []')
        return []
    }
    v.log('v.pref.lookup_path: ${v.pref.lookup_path}')
    // Lookup for built-in folder in lookup path.
    // Assumption: `builtin/` folder implies usable implementation of builtin
    for location in v.pref.lookup_path {
        if os.exists(os.join_path(location, 'builtin')) {
            mut builtin_files := []string{}
            if v.pref.backend.is_js() {
                builtin_files << v.v_files_from_dir(os.join_path(location, 'builtin', 'js'))
            } else if v.pref.backend == .wasm {
                builtin_files << v.v_files_from_dir(os.join_path(location, 'builtin', 'wasm'))
                if v.pref.os == .browser {
                    builtin_files << v.v_files_from_dir(os.join_path(location, 'builtin', 'wasm',
                        'browser'))
                } else {
                    builtin_files << v.v_files_from_dir(os.join_path(location, 'builtin', 'wasm',
                        'wasi'))
                }
            } else {
                builtin_files << v.v_files_from_dir(os.join_path(location, 'builtin'))
            }
            if v.pref.is_bare {
                builtin_files << v.v_files_from_dir(v.pref.bare_builtin_dir)
            }
            if v.pref.backend == .c {
                // TODO: JavaScript backend doesn't handle os for now
                if v.pref.is_vsh && os.exists(os.join_path(location, 'os')) {
                    builtin_files << v.v_files_from_dir(os.join_path(location, 'os'))
                }
            }
            return builtin_files
        }
    }
    // Panic. We couldn't find the folder.
    verror('`builtin/` not included on module lookup path.\nDid you forget to add vlib to the path? (Use @vlib for default vlib)')
}

pub fn (v &Builder) get_user_files() []string {
    if v.pref.path in ['vlib/builtin', 'vlib/strconv', 'vlib/strings', 'vlib/hash']
        || v.pref.path.ends_with('vlib/builtin') {
        // This means we are building a builtin module with `v build-module vlib/strings` etc
        // get_builtin_files() has already added the files in this module,
        // do nothing here to avoid duplicate definition errors.
        v.log('Skipping user files.')
        return []
    }
    mut dir := v.pref.path
    v.log('get_v_files(${dir})')
    // Need to store user files separately, because they have to be added after
    // libs, but we dont know    which libs need to be added yet
    mut user_files := []string{}
    // See cmd/tools/preludes/README.md for more info about what preludes are
    mut preludes_path := os.join_path(v.pref.vroot, 'vlib', 'v', 'preludes')
    if v.pref.backend == .js_node {
        preludes_path = os.join_path(v.pref.vroot, 'vlib', 'v', 'preludes_js')
    }
    if v.pref.trace_calls {
        user_files << os.join_path(preludes_path, 'trace_calls.v')
    }
    if v.pref.is_livemain || v.pref.is_liveshared {
        user_files << os.join_path(preludes_path, 'live.v')
    }
    if v.pref.is_livemain {
        user_files << os.join_path(preludes_path, 'live_main.v')
    }
    if v.pref.is_liveshared {
        user_files << os.join_path(preludes_path, 'live_shared.v')
    }
    if v.pref.is_test {
        if v.pref.backend == .js_node {
            user_files << os.join_path(preludes_path, 'test_runner.v')
        } else {
            user_files << os.join_path(preludes_path, 'test_runner.c.v')
        }
        //
        mut v_test_runner_prelude := os.getenv('VTEST_RUNNER')
        if v.pref.test_runner != '' {
            v_test_runner_prelude = v.pref.test_runner
        }
        if v_test_runner_prelude == '' {
            v_test_runner_prelude = 'normal'
        }
        if !v_test_runner_prelude.contains('/') && !v_test_runner_prelude.contains('\\')
            && !v_test_runner_prelude.ends_with('.v') {
            v_test_runner_prelude = os.join_path(preludes_path,
                'test_runner_${v_test_runner_prelude}.v')
        }
        if !os.is_file(v_test_runner_prelude) || !os.is_readable(v_test_runner_prelude) {
            eprintln('test runner error: File ${v_test_runner_prelude} should be readable.')
            verror('the supported test runners are: ${pref.supported_test_runners_list()}')
        }
        user_files << v_test_runner_prelude
    }
    if v.pref.is_test && v.pref.show_asserts {
        user_files << os.join_path(preludes_path, 'tests_with_stats.v')
        if v.pref.backend.is_js() {
            user_files << os.join_path(preludes_path, 'stats_import.js.v')
        }
    }
    if v.pref.is_prof {
        user_files << os.join_path(preludes_path, 'profiled_program.v')
    }
    is_test := v.pref.is_test
    mut is_internal_module_test := false
    if is_test {
        tcontent := util.read_file(dir) or { verror('${dir} does not exist') }
        slines := tcontent.split_into_lines()
        for sline in slines {
            line := sline.trim_space()
            if line.len > 2 {
                if line[0] == `/` && line[1] == `/` {
                    continue
                }
                if line.starts_with('module ') {
                    is_internal_module_test = true
                    break
                }
            }
        }
    }
    if is_internal_module_test {
        // v volt/slack_test.v: compile all .v files to get the environment
        single_test_v_file := os.real_path(dir)
        if v.pref.is_verbose {
            v.log('> Compiling an internal module _test.v file ${single_test_v_file} .')
            v.log('> That brings in all other ordinary .v files in the same module too .')
        }
        user_files << single_test_v_file
        dir = os.dir(single_test_v_file)
    }
    v.add_file_or_dir(mut user_files, dir)
    for f in v.pref.file_list {
        file := f.trim_space()
        if file.len > 0 {
            v.add_file_or_dir(mut user_files, file)
        }
    }
    if user_files.len == 0 {
        println('No input .v files')
        exit(1)
    }
    if v.pref.is_verbose {
        v.log('user_files: ${user_files}')
    }
    return user_files
}

fn (v &Builder) add_file_or_dir(mut user_files []string, dir string) {
    does_exist := os.exists(dir)
    if !does_exist {
        verror("${dir} doesn't exist")
    }
    is_real_file := does_exist && !os.is_dir(dir)
    resolved_link := if is_real_file && os.is_link(dir) { os.real_path(dir) } else { dir }
    if is_real_file && (dir.ends_with('.v') || resolved_link.ends_with('.vsh')
        || v.pref.raw_vsh_tmp_prefix != '' || dir.ends_with('.vv')) {
        single_v_file := if resolved_link.ends_with('.vsh') { resolved_link } else { dir }
        // Just compile one file and get parent dir
        user_files << single_v_file
        if v.pref.is_verbose {
            v.log('> add one file: "${single_v_file}"')
        }
    } else if os.is_dir(dir) {
        if v.pref.is_verbose {
            v.log('> add all .v files from directory "${dir}" ...')
        }
        // Add .v files from the directory being compiled
        user_files << v.v_files_from_dir(dir)
    } else {
        println('usage: `v file.v` or `v directory`')
        ext := os.file_ext(dir)
        println('unknown file extension `${ext}`')
        exit(1)
    }
}