const std = @import("std");

pub const Config = struct {
    worker_host: []const u8,
    worker_user: []const u8,
    worker_base: []const u8,
    worker_port: u16,
    api_key: []const u8,

    pub fn validate(self: Config) !void {
        // Validate host
        if (self.worker_host.len == 0) {
            return error.EmptyHost;
        }

        // Validate port range
        if (self.worker_port == 0 or self.worker_port > 65535) {
            return error.InvalidPort;
        }

        // Validate API key format (should be hex string)
        if (self.api_key.len == 0) {
            return error.EmptyAPIKey;
        }

        // Check if API key is valid hex
        for (self.api_key) |char| {
            if (!((char >= '0' and char <= '9') or
                (char >= 'a' and char <= 'f') or
                (char >= 'A' and char <= 'F')))
            {
                return error.InvalidAPIKeyFormat;
            }
        }

        // Validate base path
        if (self.worker_base.len == 0) {
            return error.EmptyBasePath;
        }
    }

    pub fn load(allocator: std.mem.Allocator) !Config {
        const home = std.posix.getenv("HOME") orelse return error.NoHomeDir;
        const config_path = try std.fmt.allocPrint(allocator, "{s}/.ml/config.toml", .{home});
        defer allocator.free(config_path);

        const file = std.fs.openFileAbsolute(config_path, .{}) catch |err| {
            if (err == error.FileNotFound) {
                std.debug.print("Config file not found. Run 'ml init' first.\n", .{});
                return error.ConfigNotFound;
            }
            return err;
        };
        defer file.close();

        // Load config with environment variable overrides
        var config = try loadFromFile(allocator, file);

        // Apply environment variable overrides
        if (std.posix.getenv("ML_HOST")) |host| {
            config.worker_host = try allocator.dupe(u8, host);
        }
        if (std.posix.getenv("ML_USER")) |user| {
            config.worker_user = try allocator.dupe(u8, user);
        }
        if (std.posix.getenv("ML_BASE")) |base| {
            config.worker_base = try allocator.dupe(u8, base);
        }
        if (std.posix.getenv("ML_PORT")) |port_str| {
            config.worker_port = try std.fmt.parseInt(u16, port_str, 10);
        }
        if (std.posix.getenv("ML_API_KEY")) |api_key| {
            config.api_key = try allocator.dupe(u8, api_key);
        }

        try config.validate();
        return config;
    }

    fn loadFromFile(allocator: std.mem.Allocator, file: std.fs.File) !Config {
        const content = try file.readToEndAlloc(allocator, 1024 * 1024);
        defer allocator.free(content);

        // Simple TOML parser - parse key=value pairs
        var config = Config{
            .worker_host = "",
            .worker_user = "",
            .worker_base = "",
            .worker_port = 22,
            .api_key = "",
        };

        var lines = std.mem.splitScalar(u8, content, '\n');
        while (lines.next()) |line| {
            const trimmed = std.mem.trim(u8, line, " \t\r");
            if (trimmed.len == 0 or trimmed[0] == '#') continue;

            var parts = std.mem.splitScalar(u8, trimmed, '=');
            const key = std.mem.trim(u8, parts.next() orelse continue, " \t");
            const value_raw = std.mem.trim(u8, parts.next() orelse continue, " \t");

            // Remove quotes
            const value = if (value_raw.len >= 2 and value_raw[0] == '"' and value_raw[value_raw.len - 1] == '"')
                value_raw[1 .. value_raw.len - 1]
            else
                value_raw;

            if (std.mem.eql(u8, key, "worker_host")) {
                config.worker_host = try allocator.dupe(u8, value);
            } else if (std.mem.eql(u8, key, "worker_user")) {
                config.worker_user = try allocator.dupe(u8, value);
            } else if (std.mem.eql(u8, key, "worker_base")) {
                config.worker_base = try allocator.dupe(u8, value);
            } else if (std.mem.eql(u8, key, "worker_port")) {
                config.worker_port = try std.fmt.parseInt(u16, value, 10);
            } else if (std.mem.eql(u8, key, "api_key")) {
                config.api_key = try allocator.dupe(u8, value);
            }
        }

        return config;
    }

    pub fn save(self: Config, allocator: std.mem.Allocator) !void {
        const home = std.posix.getenv("HOME") orelse return error.NoHomeDir;

        // Create .ml directory
        const ml_dir = try std.fmt.allocPrint(allocator, "{s}/.ml", .{home});
        defer allocator.free(ml_dir);

        std.fs.makeDirAbsolute(ml_dir) catch |err| {
            if (err != error.PathAlreadyExists) return err;
        };

        const config_path = try std.fmt.allocPrint(allocator, "{s}/config.toml", .{ml_dir});
        defer allocator.free(config_path);

        const file = try std.fs.createFileAbsolute(config_path, .{});
        defer file.close();

        const writer = file.writer();
        try writer.print("worker_host = \"{s}\"\n", .{self.worker_host});
        try writer.print("worker_user = \"{s}\"\n", .{self.worker_user});
        try writer.print("worker_base = \"{s}\"\n", .{self.worker_base});
        try writer.print("worker_port = {d}\n", .{self.worker_port});
        try writer.print("api_key = \"{s}\"\n", .{self.api_key});
    }

    pub fn deinit(self: *Config, allocator: std.mem.Allocator) void {
        allocator.free(self.worker_host);
        allocator.free(self.worker_user);
        allocator.free(self.worker_base);
        allocator.free(self.api_key);
    }
};