const std = @import("std");
const patterns = @import("patterns.zig");
const codegen = @import("codegen.zig");
const dependency_resolver = @import("dependency_resolver.zig");
const json_serializer = @import("json_serializer.zig");
const io = @import("io.zig");
const header_cache = @import("header_cache.zig");

pub fn freeDecls(allocator: std.mem.Allocator, decls: []patterns.Declaration) void {
    for (decls) |decl| {
        freeDeclDeep(allocator, decl);
    }
    allocator.free(decls);
}

pub fn main() !void {
    const allocator = std.heap.smp_allocator;

    const args = try std.process.argsAlloc(allocator);
    defer std.process.argsFree(allocator, args);

    if (args.len < 2) {
        std.debug.print("Usage: {s} <header-file> [--output=<output-file>] [--mocks=<mock-file>] [--generate-json=<json-file>] [--timestamp=<timestamp>] [--basedir=<directory>]\n", .{args[0]});
        std.debug.print("Example: {s} ../SDL/include/SDL3/SDL_gpu.h --output=gpu.zig\n", .{args[0]});
        std.debug.print("         {s} ../SDL/include/SDL3/SDL_gpu.h --output=gpu.zig --mocks=gpu_mock.c\n", .{args[0]});
        std.debug.print("         {s} ../SDL/include/SDL3/SDL_gpu.h --generate-json=gpu.json\n", .{args[0]});
        std.debug.print("         {s} ../SDL/include/SDL3/SDL_gpu.h > gpu.zig\n", .{args[0]});
        std.debug.print("         {s} ../SDL/include/SDL3/SDL_gpu.h --basedir=/path/to/workdir\n", .{args[0]});
        return error.MissingArgument;
    }

    const header_path = args[1];

    var output_file: ?[]const u8 = null;
    var mock_output_file: ?[]const u8 = null;
    var json_output_file: ?[]const u8 = null;
    var timestamp: ?i64 = null;
    var basedir: ?[]const u8 = null;

    // Parse additional flags
    for (args[2..]) |arg| {
        const output_prefix = "--output=";
        const mocks_prefix = "--mocks=";
        const json_prefix = "--generate-json=";
        const timestamp_prefix = "--timestamp=";
        const basedir_prefix = "--basedir=";
        if (std.mem.startsWith(u8, arg, output_prefix)) {
            output_file = arg[output_prefix.len..];
        } else if (std.mem.startsWith(u8, arg, mocks_prefix)) {
            mock_output_file = arg[mocks_prefix.len..];
        } else if (std.mem.startsWith(u8, arg, json_prefix)) {
            json_output_file = arg[json_prefix.len..];
        } else if (std.mem.startsWith(u8, arg, timestamp_prefix)) {
            timestamp = std.fmt.parseInt(i64, arg[timestamp_prefix.len..], 10) catch null;
        } else if (std.mem.startsWith(u8, arg, basedir_prefix)) {
            basedir = arg[basedir_prefix.len..];
        } else {
            std.debug.print("Error: Unknown argument '{s}'\n", .{arg});
            std.debug.print("Usage: {s} <header-file> [--output=<output-file>] [--mocks=<mock-file>] [--generate-json=<json-file>] [--timestamp=<timestamp>] [--basedir=<directory>]\n", .{args[0]});
            return error.InvalidArgument;
        }
    }

    // Change working directory if --basedir is specified
    if (basedir) |dir| {
        try std.posix.chdir(dir);
        std.debug.print("Changed working directory to: {s}\n\n", .{dir});
    }

    // Archive any existing debug directory before this run
    archiveExistingDebugDir(allocator, timestamp);

    std.debug.print("SDL3 Header Parser\n", .{});
    std.debug.print("==================\n\n", .{});
    std.debug.print("Parsing: {s}\n\n", .{header_path});

    // Read the header file
    const source = try std.fs.cwd().readFileAlloc(allocator, header_path, 10 * 1024 * 1024); // 10MB max
    defer allocator.free(source);

    // Parse declarations
    var scanner = patterns.Scanner.init(allocator, source);
    const decls = try scanner.scan();
    defer freeDecls(allocator, decls);

    std.debug.print("Found {d} declarations\n", .{decls.len});

    // Count each type
    var opaque_count: usize = 0;
    var typedef_count: usize = 0;
    var func_ptr_count: usize = 0;
    var c_type_alias_count: usize = 0;
    var enum_count: usize = 0;
    var struct_count: usize = 0;
    var union_count: usize = 0;
    var flag_count: usize = 0;
    var func_count: usize = 0;

    for (decls) |decl| {
        switch (decl) {
            .opaque_type => opaque_count += 1,
            .typedef_decl => typedef_count += 1,
            .function_pointer_decl => func_ptr_count += 1,
            .c_type_alias => c_type_alias_count += 1,
            .enum_decl => enum_count += 1,
            .struct_decl => struct_count += 1,
            .union_decl => union_count += 1,
            .flag_decl => flag_count += 1,
            .function_decl => func_count += 1,
        }
    }

    std.debug.print("  - Opaque types: {d}\n", .{opaque_count});
    std.debug.print("  - Typedefs: {d}\n", .{typedef_count});
    std.debug.print("  - Function pointers: {d}\n", .{func_ptr_count});
    std.debug.print("  - C type aliases: {d}\n", .{c_type_alias_count});
    std.debug.print("  - Enums: {d}\n", .{enum_count});
    std.debug.print("  - Structs: {d}\n", .{struct_count});
    std.debug.print("  - Unions: {d}\n", .{union_count});
    std.debug.print("  - Flags: {d}\n", .{flag_count});
    std.debug.print("  - Functions: {d}\n\n", .{func_count});

    // Generate JSON if requested
    if (json_output_file) |json_path| {
        std.debug.print("Generating JSON output...\n", .{});

        var serializer = json_serializer.JsonSerializer.init(allocator, std.fs.path.basename(header_path));

        try serializer.addDeclarations(decls);
        const json_output = try serializer.finalize();
        // json_output is owned by serializer

        // Parse and re-format JSON with proper indentation
        const parsed = try std.json.parseFromSlice(std.json.Value, allocator, json_output, .{});
        defer parsed.deinit();

        var formatted_output = std.ArrayList(u8){};
        defer formatted_output.deinit(allocator);

        const formatter = std.json.fmt(parsed.value, .{ .whitespace = .indent_2 });
        try std.fmt.format(formatted_output.writer(allocator), "{f}", .{formatter});

        try ensureParentDirExists(json_path);
        try std.fs.cwd().writeFile(.{
            .sub_path = json_path,
            .data = formatted_output.items,
        });
        serializer.deinit();
        std.debug.print("Generated JSON: {s}\n", .{json_path});

        // If only JSON was requested, we're done
        if (output_file == null and mock_output_file == null) {
            return;
        }
    }

    // Analyze dependencies
    std.debug.print("Analyzing dependencies...\n", .{});
    var resolver = dependency_resolver.DependencyResolver.init(allocator);
    defer resolver.deinit();

    try resolver.analyze(decls);
    const missing_types = try resolver.getMissingTypes(allocator);
    defer {
        for (missing_types) |t| allocator.free(t);
        allocator.free(missing_types);
    }

    // Get hardcoded declarations for special types (like SDL_HitTest)
    //  const hardcoded_decls = try resolver.getHardcodedDeclarations(allocator);
    //  defer {
    //      for (hardcoded_decls) |hd| {
    //          freeDeclDeep(allocator, hd);
    //      }
    //      allocator.free(hardcoded_decls);
    //  }

    // if (hardcoded_decls.len > 0) {
    //     std.debug.print("Adding {d} hardcoded type declarations\n", .{hardcoded_decls.len});
    // }

    var dependency_decls = std.ArrayList(patterns.Declaration){};
    defer {
        for (dependency_decls.items) |dep_decl| {
            freeDeclDeep(allocator, dep_decl);
        }
        dependency_decls.deinit(allocator);
    }

    if (missing_types.len > 0) {
        std.debug.print("Found {d} missing types:\n", .{missing_types.len});
        for (missing_types) |missing| {
            std.debug.print("  - {s}\n", .{missing});
        }
        std.debug.print("\n", .{});

        // PHASE 1: Build complete type cache from all SDL headers
        std.debug.print("Building type cache from all SDL headers...\n", .{});
        var cache = try header_cache.HeaderCache.buildCache(allocator, header_path);
        defer cache.deinit();
        std.debug.print("Type cache built successfully\n\n", .{});

        // PHASE 2: Resolve dependencies via cache lookup with recursive dependency resolution
        std.debug.print("Resolving dependencies from cache...\n", .{});

        // Track which types we've already added to avoid duplicates
        var added_types = std.StringHashMap(void).init(allocator);
        defer {
            var it = added_types.keyIterator();
            while (it.next()) |key| {
                allocator.free(key.*);
            }
            added_types.deinit();
        }

        for (missing_types) |missing_type| {
            // Skip if already added
            if (added_types.contains(missing_type)) continue;

            // Look up type with all its dependencies
            const resolved_decls = cache.lookupTypeWithDependencies(missing_type) catch |err| {
                std.debug.print("  Warning: Could not resolve {s}: {}\n", .{ missing_type, err });
                continue;
            };

            // Add all resolved declarations
            for (resolved_decls) |resolved_decl| {
                const decl_type_name = switch (resolved_decl) {
                    .opaque_type => |o| o.name,
                    .typedef_decl => |t| t.name,
                    .function_pointer_decl => |fp| fp.name,
                    .c_type_alias => |a| a.name,
                    .enum_decl => |e| e.name,
                    .struct_decl => |s| s.name,
                    .union_decl => |u| u.name,
                    .flag_decl => |f| f.name,
                    .function_decl => continue, // Skip functions
                };

                if (!added_types.contains(decl_type_name)) {
                    try dependency_decls.append(allocator, resolved_decl);
                    try added_types.put(try allocator.dupe(u8, decl_type_name), {});

                    if (std.mem.eql(u8, decl_type_name, missing_type)) {
                        std.debug.print("  Found {s} in cache\n", .{missing_type});
                    } else {
                        std.debug.print("    + dependency: {s}\n", .{decl_type_name});
                    }
                } else {
                    // Already added, free this duplicate
                    freeDeclDeep(allocator, resolved_decl);
                }
            }

            allocator.free(resolved_decls);
        }

        std.debug.print("\n", .{});
    }

    // Combine declarations (hardcoded first, then dependencies, then primary!)
    std.debug.print("Combining {d} dependency declarations with primary declarations...\n", .{dependency_decls.items.len});

    var all_decls = std.ArrayList(patterns.Declaration){};
    defer all_decls.deinit(allocator);

    // try all_decls.appendSlice(allocator, hardcoded_decls);
    try all_decls.appendSlice(allocator, dependency_decls.items);
    try all_decls.appendSlice(allocator, decls);

    // Generate code with all declarations
    const output = try codegen.CodeGen.generate(allocator, all_decls.items);
    defer allocator.free(output);

    // Parse and format the AST for validation
    const output_z = try allocator.dupeZ(u8, output);
    defer allocator.free(output_z);

    var ast = try std.zig.Ast.parse(allocator, output_z, .zig);
    defer ast.deinit(allocator);

    // Check for parse errors
    if (ast.errors.len > 0) {
        std.debug.print("{s}", .{output_z});
        std.debug.print("\nError: {d} syntax errors detected in generated code\n", .{ast.errors.len});
        for (ast.errors) |err| {
            const loc = ast.tokenLocation(0, err.token);
            std.debug.print("  Line {d}: {s}\n", .{ loc.line + 1, @tagName(err.tag) });
        }

        // Write to debug file
        try writeDebugFile(allocator, header_path, output);

        // Write unformatted output for debugging
        if (output_file) |file_path| {
            try std.fs.cwd().writeFile(.{
                .sub_path = file_path,
                .data = output,
            });
            std.debug.print("\nGenerated (with errors): {s}\n", .{file_path});
        }

        return error.InvalidSyntax;
    }

    // Render formatted output from AST
    const formatted_output = ast.renderAlloc(allocator) catch |err| {
        std.debug.print("\nError: AST render failed: {}\n", .{err});
        try writeDebugFile(allocator, header_path, output);
        return err;
    };
    defer allocator.free(formatted_output);

    // Write formatted output to file or stdout
    if (output_file) |file_path| {
        try writeZigFileWithFmt(allocator, header_path, file_path, formatted_output);
    } else {
        _ = try io.stdout().write(formatted_output);
    }

    // Generate C mocks if requested (with all declarations)
    if (mock_output_file) |mock_path| {
        const mock_codegen = @import("mock_codegen.zig");
        const mock_output = try mock_codegen.MockCodeGen.generate(allocator, all_decls.items);
        defer allocator.free(mock_output);

        try ensureParentDirExists(mock_path);
        try std.fs.cwd().writeFile(.{
            .sub_path = mock_path,
            .data = mock_output,
        });
        std.debug.print("Generated C mocks: {s}\n", .{mock_path});
    }
}

fn writeZigFileWithFmt(allocator: std.mem.Allocator, header_path: []const u8, output_path: []const u8, content: []const u8) !void {
    const header_basename = std.fs.path.basename(header_path);
    const output_basename = std.fs.path.basename(output_path);

    // Create tmp directory
    std.fs.cwd().makePath("tmp") catch |err| switch (err) {
        error.PathAlreadyExists => {},
        else => return err,
    };

    // Write to tmp file
    const tmp_path = try std.fmt.allocPrint(allocator, "tmp/{s}", .{output_basename});
    defer allocator.free(tmp_path);

    try std.fs.cwd().writeFile(.{
        .sub_path = tmp_path,
        .data = content,
    });

    // Run zig ast-check on tmp file
    var ast_check = std.process.Child.init(&.{ "zig", "ast-check", tmp_path }, allocator);
    ast_check.stderr_behavior = .Pipe;
    try ast_check.spawn();
    const ast_result = try ast_check.wait();

    if (ast_result.Exited != 0) {
        // zig ast-check failed - copy to debug folder
        std.fs.cwd().makePath("debug") catch |err| switch (err) {
            error.PathAlreadyExists => {},
            else => return err,
        };

        // Convert header name: SDL_gpu.h -> SDL_gpu_h
        var safe_name = try allocator.alloc(u8, header_basename.len);
        defer allocator.free(safe_name);
        for (header_basename, 0..) |c, i| {
            safe_name[i] = if (c == '.') '_' else c;
        }

        const debug_path = try std.fmt.allocPrint(allocator, "debug/{s}_fmterror.zig", .{safe_name});
        defer allocator.free(debug_path);

        try std.fs.cwd().writeFile(.{
            .sub_path = debug_path,
            .data = content,
        });
        std.debug.print("zig ast-check failed, debug output written to: {s}\n", .{debug_path});
        return error.ZigAstCheckFailed;
    }

    // Run zig fmt on tmp file
    var fmt = std.process.Child.init(&.{ "zig", "fmt", tmp_path }, allocator);
    fmt.stderr_behavior = .Pipe;
    try fmt.spawn();
    _ = try fmt.wait();

    // Copy formatted file to final destination
    try ensureParentDirExists(output_path);

    const formatted_content = try std.fs.cwd().readFileAlloc(allocator, tmp_path, 10 * 1024 * 1024);
    defer allocator.free(formatted_content);

    try std.fs.cwd().writeFile(.{
        .sub_path = output_path,
        .data = formatted_content,
    });
    std.debug.print("Generated: {s}\n", .{output_path});
}

fn ensureParentDirExists(path: []const u8) !void {
    if (std.fs.path.dirname(path)) |dir| {
        std.fs.cwd().makePath(dir) catch |err| switch (err) {
            error.PathAlreadyExists => {},
            else => return err,
        };
    }
}

fn archiveExistingDebugDir(allocator: std.mem.Allocator, provided_timestamp: ?i64) void {
    // Check if debug/ directory exists
    var debug_dir = std.fs.cwd().openDir("debug", .{}) catch return;
    debug_dir.close();

    // Use provided timestamp or generate one
    const timestamp = provided_timestamp orelse std.time.timestamp();
    const archive_path = std.fmt.allocPrint(allocator, "archive/debug/{d}", .{timestamp}) catch return;
    defer allocator.free(archive_path);

    // Create archive/debug directory if needed
    std.fs.cwd().makePath("archive/debug") catch return;

    // Move debug/ to archive/debug/<timestamp>/
    std.fs.cwd().rename("debug", archive_path) catch |err| {
        std.debug.print("Warning: Failed to archive existing debug dir: {}\n", .{err});
        return;
    };

    std.debug.print("Archived existing debug/ to {s}\n", .{archive_path});
}

fn writeDebugFile(allocator: std.mem.Allocator, header_path: []const u8, output: []const u8) !void {
    // Get the header basename (e.g., "SDL_gpu.h")
    const header_basename = std.fs.path.basename(header_path);

    // Convert to safe filename: SDL_gpu.h -> error_SDL_gpu_h.zig
    var safe_name = try allocator.alloc(u8, header_basename.len);
    defer allocator.free(safe_name);
    for (header_basename, 0..) |c, i| {
        safe_name[i] = if (c == '.') '_' else c;
    }

    const debug_filename = try std.fmt.allocPrint(allocator, "debug/error_{s}.zig", .{safe_name});
    defer allocator.free(debug_filename);

    // Create debug directory if it doesn't exist
    std.fs.cwd().makeDir("debug") catch |err| switch (err) {
        error.PathAlreadyExists => {},
        else => return err,
    };

    try std.fs.cwd().writeFile(.{
        .sub_path = debug_filename,
        .data = output,
    });
    std.debug.print("Debug output written to: {s}\n", .{debug_filename});
}

fn freeDeclDeep(allocator: std.mem.Allocator, decl: patterns.Declaration) void {
    switch (decl) {
        inline else => |*d| d.deinit(allocator),
    }
}

test "basic test" {
    try std.testing.expect(true);
}