const std = @import("std");

const scanners = @import("scanners.zig");
const parsers = @import("parsers.zig");
const printer = @import("ast_printer.zig");
const codegen = @import("codegen.zig");
const types = @import("types.zig");

pub const Result = enum {
    Ok,
    TokenizeError,
    ParseError,
    CompileError,
};

pub fn run(allocator: *std.mem.Allocator, slice: []const u8) !Result {
    var scan = scanners.Scanner.init(allocator, slice);

    // do a full scan pass, then reset, then do it again (with parser)
    while (true) {
        var tok_opt = scan.nextToken() catch |err| {
            std.debug.warn(
                "error at '{}': {}\n",
                scan.currentLexeme(),
                err,
            );

            return Result.TokenizeError;
        };

        if (tok_opt) |tok| {
            if (tok.typ == .EOF) break;

            // TODO remove
            std.debug.warn("{x}\n", tok);
        }
    }

    scan.reset();

    var parser = parsers.Parser.init(allocator, &scan);
    var root_opt = try parser.parse();

    if (root_opt == null) {
        return Result.ParseError;
    }

    var root = root_opt.?;

    std.debug.warn("parse tree\n");
    printer.printNode(root, 0);

    var solver = types.TypeSolver.init(allocator);
    var ctx = try solver.pass(root);

    std.debug.warn("symbol table\n");
    printer.printContext(ctx);

    var cgen = codegen.Codegen.init(allocator, &ctx);
    try cgen.gen(root);

    return Result.Ok;
}

pub fn main() anyerror!void {
    const allocator = std.heap.direct_allocator;
    var args_it = std.process.args();
    _ = args_it.skip();

    const filepath = try (args_it.next(allocator) orelse @panic("expected file path"));

    var file = try std.fs.File.openRead(filepath);
    defer file.close();

    const total_bytes = try file.getEndPos();

    var slice = try allocator.alloc(u8, total_bytes);
    defer allocator.free(slice);

    _ = try file.read(slice);

    const result = try run(allocator, slice);
    switch (result) {
        .Ok => std.os.exit(0),

        .TokenizeError,
        .ParseError,
        .CompileError,
        => {
            std.debug.warn("error: {}\n", result);
            std.os.exit(1);
        },
    }
}