// cli.bux — CLI driver for the Bux self-hosting compiler
// Wires together: Lexer → Parser → Sema → HirLower → CBackend
module Cli {

extern func PrintLine(s: String);
extern func Print(s: String);
extern func bux_read_file(path: String) -> String;
extern func bux_write_file(path: String, content: String) -> bool;
extern func bux_file_exists(path: String) -> int;
extern func bux_dir_exists(path: String) -> int;
extern func bux_path_join(a: String, b: String) -> String;
extern func bux_mkdir_if_needed(path: String) -> int;
extern func bux_run_cc(c_file: String, out_bin: String, runtime_c: String, io_c: String, math_lib: String) -> int;
extern func bux_list_dir(dir: String, ext: String, out_count: *int) -> *String;

func ReadFile(path: String) -> String {
    return bux_read_file(path);
}

func WriteFile(path: String, content: String) -> bool {
    return bux_write_file(path, content);
}

func FileExists(path: String) -> bool {
    return bux_file_exists(path) != 0;
}

func DirExists(path: String) -> bool {
    return bux_dir_exists(path) != 0;
}

// Import the compiler pipeline
// In self-hosting mode, these are compiled together from src_bux/

// ---------------------------------------------------------------------------
// Compile a single .bux source file
// ---------------------------------------------------------------------------

func Cli_Compile(source: String, sourceName: String) -> String {
    // Phase 1: Lex
    let lex: *Lexer = Lexer_Tokenize(source);
    if Lexer_DiagCount(lex) > 0 {
        PrintLine("Lex errors:");
        var i: int = 0;
        while i < Lexer_DiagCount(lex) {
            Print("  ");
            PrintLine(lex.diags[i].message);
            i = i + 1;
        }
        return "";
    }

    // Phase 2: Parse
    let mod: *Module = Parser_Parse(lex.tokens, lex.tokenCount);
    if mod == null as *Module {
        PrintLine("Parse failed");
        return "";
    }

    // Phase 3: Semantic analysis
    let sema: *Sema = Sema_Analyze(mod);
    if Sema_HasError(sema) {
        PrintLine("Sema errors:");
        var i: int = 0;
        while i < Sema_DiagCount(sema) {
            Print("  ");
            PrintLine(sema.diags[i].message);
            i = i + 1;
        }
        return "";
    }

    // Phase 4: HIR lowering
    let hirMod: *HirModule = HirLower_LowerModule(mod, sema);
    if hirMod == null as *HirModule {
        PrintLine("HIR lowering failed");
        return "";
    }
    Print("HIR funcCount=");
    PrintInt(hirMod.funcCount);
    PrintLine("");

    // Phase 5: C code generation
    let cCode: String = CBackend_Generate(hirMod);

    // Cleanup
    Lexer_Free(lex);
    Sema_Free(sema);

    return cCode;
}

// ---------------------------------------------------------------------------
// Build command
// ---------------------------------------------------------------------------

func Cli_Build(srcPath: String, outPath: String) -> int {
    let source: String = ReadFile(srcPath);
    if String_Eq(source, "") || !FileExists(srcPath) {
        Print("Error: cannot read source file: ");
        PrintLine(srcPath);
        return 1;
    }

    Print("Compiling ");
    PrintLine(srcPath);

    let cCode: String = Cli_Compile(source, srcPath);

    if String_Eq(cCode, "") {
        PrintLine("Compilation failed");
        return 1;
    }

    // Write C output
    let ok: bool = WriteFile(outPath, cCode);
    if ok {
        Print("  → C code written to ");
        PrintLine(outPath);
        return 0;
    } else {
        PrintLine("Error: cannot write output file");
        return 1;
    }
}

// ---------------------------------------------------------------------------
// Check command (compile only, no output)
// ---------------------------------------------------------------------------

func Cli_Check(srcPath: String) -> int {
    let source: String = ReadFile(srcPath);
    if String_Eq(source, "") {
        PrintLine("Error: cannot read source file");
        return 1;
    }

    let cCode: String = Cli_Compile(source, srcPath);
    if String_Eq(cCode, "") {
        return 1;
    }

    PrintLine("Check passed");
    return 0;
}

// ---------------------------------------------------------------------------
// Project build — compile all .bux files in src/ directory
// ---------------------------------------------------------------------------

func Cli_CompileSource(source: String, sourceName: String) -> *HirModule {
    // Phase 1: Lex
    let lex: *Lexer = Lexer_Tokenize(source);
    if Lexer_DiagCount(lex) > 0 {
        Print("Lex errors in ");
        PrintLine(sourceName);
        return null as *HirModule;
    }

    // Phase 2: Parse
    let mod: *Module = Parser_Parse(lex.tokens, lex.tokenCount);
    if mod == null as *Module {
        Print("Parse failed for ");
        PrintLine(sourceName);
        return null as *HirModule;
    }

    // Phase 3: Semantic analysis
    let sema: *Sema = Sema_Analyze(mod);
    if Sema_HasError(sema) {
        Print("Sema errors in ");
        PrintLine(sourceName);
        return null as *HirModule;
    }

    // Phase 4: HIR lowering
    let hirMod: *HirModule = HirLower_LowerModule(mod, sema);
    return hirMod;
}

func Cli_BuildProject(projectDir: String) -> int {
    let srcDir: String = bux_path_join(projectDir, "src");
    if !DirExists(srcDir) {
        Print("Error: no src/ directory in ");
        PrintLine(projectDir);
        return 1;
    }

    Print("Scanning ");
    PrintLine(srcDir);

    // List all .bux files in src/
    var fileCount: int = 0;
    let files: *String = bux_list_dir(srcDir, ".bux", &fileCount);
    if fileCount == 0 {
        PrintLine("Error: no .bux files found in src/");
        return 1;
    }

    Print("Found ");
    PrintInt(fileCount);
    PrintLine(" source files");

    // Create merged module
    let merged: *Module = bux_alloc(sizeof(Module)) as *Module;
    merged.name = "main";
    merged.path = "";
    merged.itemCount = 0;
    merged.firstItem = null as *Decl;

    // Parse each file and merge declarations into merged module
    var i: int = 0;
    while i < fileCount {
        let path: String = files[i];
        Print("  Parsing ");
        PrintLine(path);
        let source: String = ReadFile(path);
        if String_Eq(source, "") {
            Print("  Error: cannot read ");
            PrintLine(path);
            return 1;
        }
        let lex: *Lexer = Lexer_Tokenize(source);
        if Lexer_DiagCount(lex) > 0 {
            Print("  Lex errors in ");
            PrintLine(path);
            return 1;
        }
        let mod: *Module = Parser_Parse(lex.tokens, lex.tokenCount);
        if mod == null as *Module {
            Print("  Parse failed for ");
            PrintLine(path);
            return 1;
        }
        // Merge declarations from this module into merged
        var decl: *Decl = mod.firstItem;
        while decl != null as *Decl {
            let next: *Decl = decl.childDecl2;
            decl.childDecl2 = null as *Decl;
            // Flatten module declarations
            if decl.kind == dkModule {
                var inner: *Decl = decl.childDecl1;
                while inner != null as *Decl {
                    let innerNext: *Decl = inner.childDecl2;
                    inner.childDecl2 = merged.firstItem;
                    merged.firstItem = inner;
                    merged.itemCount = merged.itemCount + 1;
                    inner = innerNext;
                }
            } else {
                decl.childDecl2 = merged.firstItem;
                merged.firstItem = decl;
                merged.itemCount = merged.itemCount + 1;
            }
            decl = next;
        }
        i = i + 1;
    }

    Print("Merged ");
    PrintInt(merged.itemCount);
    PrintLine(" declarations");

    // Semantic analysis
    PrintLine("Running sema...");
    let sema: *Sema = Sema_Analyze(merged);
    if Sema_HasError(sema) {
        PrintLine("Sema errors found");
        return 1;
    }

    // HIR lowering
    PrintLine("Lowering to HIR...");
    let hirMod: *HirModule = HirLower_LowerModule(merged, sema);

    // C code generation
    PrintLine("Generating C code...");
    let cCode: String = CBackend_Generate(hirMod);

    // Create build directory
    let buildDir: String = bux_path_join(projectDir, "build");
    discard bux_mkdir_if_needed(buildDir);

    // Write C output
    let cFile: String = bux_path_join(buildDir, "main.c");
    if !WriteFile(cFile, cCode) {
        PrintLine("Error: cannot write main.c");
        return 1;
    }

    Print("C code written to ");
    PrintLine(cFile);

    // Find stdlib files
    let runtimeC: String = bux_path_join(bux_path_join(projectDir, ".."), "stdlib/runtime.c");
    let ioC: String = bux_path_join(bux_path_join(projectDir, ".."), "stdlib/io.c");

    // Invoke C compiler
    PrintLine("Invoking C compiler...");
    let outBin: String = bux_path_join(buildDir, "buxc3");
    let rc: int = bux_run_cc(cFile, outBin, runtimeC, ioC, "-lm");
    if rc != 0 {
        PrintLine("Error: C compilation failed");
        return 1;
    }

    Print("Build successful: ");
    PrintLine(outBin);
    return 0;
}

// ---------------------------------------------------------------------------
// Main entry — dispatch based on args
// ---------------------------------------------------------------------------

func Cli_Run(args: *String, argCount: int) -> int {
    if argCount < 2 {
        PrintLine("Bux Self-Hosting Compiler v0.2.0");
        PrintLine("Usage: buxc <command> [args]");
        PrintLine("Commands: build, check, run, version");
        PrintLine("");
        PrintLine("Pipeline modules:");
        PrintLine("  Lexer      ✅  695 lines");
        PrintLine("  Parser     ✅ 1004 lines");
        PrintLine("  Sema       ✅  393 lines");
        PrintLine("  HirLower   ✅  307 lines");
        PrintLine("  CBackend   ✅  264 lines");
        PrintLine("  Total: 3830 lines of Bux");
        return 0;
    }

    let cmd: String = args[1];
    if String_Eq(cmd, "version") {
        PrintLine("Bux 0.2.0 (self-hosting bootstrap)");
        return 0;
    }

    if String_Eq(cmd, "check") {
        if argCount < 3 {
            PrintLine("Usage: buxc check <file.bux>");
            return 1;
        }
        return Cli_Check(args[2]);
    }

    if String_Eq(cmd, "build") {
        let src: String = "src/Main.bux";
        let out: String = "build/main.c";
        if argCount >= 3 { src = args[2]; }
        if argCount >= 4 { out = args[3]; }
        return Cli_Build(src, out);
    }

    if String_Eq(cmd, "project") {
        let dir: String = ".";
        if argCount >= 3 { dir = args[2]; }
        return Cli_BuildProject(dir);
    }

    Print("Unknown command: ");
    PrintLine(cmd);
    return 1;
}
}