const std = @import("std");
const types = @import("lib/types.zig");
const CommandContext = types.CommandContext;
const CommandStatus = types.CommandStatus;
const OutputCapture = types.OutputCapture;

pub const Help = struct {
    command: ?[]const u8 = null,

    pub fn eval(self: Help, ctx: CommandContext) !CommandStatus {
        if (self.command) |cmd| {
            return showCommandHelp(cmd, ctx);
        } else {
            return showGeneralHelp(ctx);
        }
    }
};

fn showGeneralHelp(ctx: CommandContext) !CommandStatus {
    const help_text =
        \\DOSE - DOS-style Command Shell
        \\
        \\Available commands:
        \\
        \\File Operations:
        \\  COPY     - Copy files
        \\  DIR      - Display directory contents
        \\  TYPE     - Display file contents
        \\  CD       - Change directory
        \\  MD       - Create directory
        \\  RD       - Remove directory
        \\  REN      - Rename files/directories
        \\  DEL      - Delete files
        \\  MOVE     - Move files/directories
        \\
        \\System Commands:
        \\  ECHO     - Display messages or control echo state
        \\  CLS      - Clear screen
        \\  DATE     - Display current date
        \\  TIME     - Display current time
        \\  VER      - Display version information
        \\  PATH     - Display or set PATH environment variable
        \\  SORT     - Sort input lines alphabetically
        \\  EXIT     - Exit the shell
        \\
        \\For help on a specific command, type: command /?
        \\Example: DIR /?
        \\
    ;

    if (ctx.output_capture) |output| {
        try output.write(help_text);
    } else {
        try std.io.getStdOut().writeAll(help_text);
    }

    return CommandStatus{ .Code = 0 };
}

fn showCommandHelp(command: []const u8, ctx: CommandContext) !CommandStatus {
    const cmd_upper = try std.ascii.allocUpperString(ctx.allocator, command);
    defer ctx.allocator.free(cmd_upper);

    const help_text = getCommandSpecificHelp(cmd_upper);

    if (ctx.output_capture) |output| {
        try output.write(help_text);
    } else {
        try std.io.getStdOut().writeAll(help_text);
    }

    return CommandStatus{ .Code = 0 };
}

fn getCommandSpecificHelp(command: []const u8) []const u8 {
    if (std.mem.eql(u8, command, "DIR")) {
        return 
        \\DIR - Display directory contents
        \\
        \\Syntax: DIR [path] [/flags]
        \\
        \\  path     Directory path to list (default: current directory)
        \\
        \\Flags:
        \\  /?       Display this help message
        \\  /W       Use wide list format (filenames only, multiple columns)
        \\  /B       Use bare format (filenames only, one per line)
        \\  /S       Display files in subdirectories as well
        \\
        \\Example: DIR C:\ /W
        \\
        ;
    } else if (std.mem.eql(u8, command, "COPY")) {
        return 
        \\COPY - Copy files
        \\
        \\Syntax: COPY source destination [/flags]
        \\
        \\  source      Source file or device
        \\  destination Destination file or device
        \\
        \\Flags:
        \\  /?          Display this help message
        \\  /Y          Suppress prompting to confirm overwrite
        \\
        \\Example: COPY file1.txt file2.txt
        \\
        ;
    } else if (std.mem.eql(u8, command, "TYPE")) {
        return 
        \\TYPE - Display file contents
        \\
        \\Syntax: TYPE filename [/flags]
        \\
        \\  filename    File to display
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: TYPE readme.txt
        \\
        ;
    } else if (std.mem.eql(u8, command, "CD") or std.mem.eql(u8, command, "CHDIR")) {
        return 
        \\CD/CHDIR - Change directory
        \\
        \\Syntax: CD [path] [/flags]
        \\
        \\  path        Directory to change to
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: CD C:\Windows
        \\
        ;
    } else if (std.mem.eql(u8, command, "ECHO")) {
        return 
        \\ECHO - Display messages or control echo state
        \\
        \\Syntax: ECHO [message] [/flags]
        \\        ECHO ON|OFF
        \\
        \\  message     Text to display
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: ECHO Hello World
        \\
        ;
    } else if (std.mem.eql(u8, command, "CLS")) {
        return 
        \\CLS - Clear screen
        \\
        \\Syntax: CLS [/flags]
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        ;
    } else if (std.mem.eql(u8, command, "EXIT")) {
        return 
        \\EXIT - Exit the shell
        \\
        \\Syntax: EXIT [/flags]
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        ;
    } else if (std.mem.eql(u8, command, "VER")) {
        return 
        \\VER - Display version information
        \\
        \\Syntax: VER [/flags]
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        ;
    } else if (std.mem.eql(u8, command, "DATE")) {
        return 
        \\DATE - Display current date
        \\
        \\Syntax: DATE [/flags]
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        ;
    } else if (std.mem.eql(u8, command, "TIME")) {
        return 
        \\TIME - Display current time
        \\
        \\Syntax: TIME [/flags]
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        ;
    } else if (std.mem.eql(u8, command, "MD") or std.mem.eql(u8, command, "MKDIR")) {
        return 
        \\MD/MKDIR - Create directory
        \\
        \\Syntax: MD directory [/flags]
        \\        MKDIR directory [/flags]
        \\
        \\  directory   Directory path to create
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: MD C:\TEMP
        \\Note: Creates intermediate directories if needed
        \\
        ;
    } else if (std.mem.eql(u8, command, "RD") or std.mem.eql(u8, command, "RMDIR")) {
        return 
        \\RD/RMDIR - Remove directory
        \\
        \\Syntax: RD directory [/flags]
        \\        RMDIR directory [/flags]
        \\
        \\  directory   Directory path to remove
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: RD C:\TEMP
        \\Note: Directory must be empty
        \\
        ;
    } else if (std.mem.eql(u8, command, "REN") or std.mem.eql(u8, command, "RENAME")) {
        return 
        \\REN/RENAME - Rename files or directories
        \\
        \\Syntax: REN oldname newname [/flags]
        \\        RENAME oldname newname [/flags]
        \\
        \\  oldname     Current name of file or directory
        \\  newname     New name for file or directory
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: REN file1.txt file2.txt
        \\
        ;
    } else if (std.mem.eql(u8, command, "MOVE")) {
        return 
        \\MOVE - Move files or directories
        \\
        \\Syntax: MOVE source destination [/flags]
        \\
        \\  source      Source file or directory
        \\  destination Destination path
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: MOVE file1.txt C:\TEMP\file1.txt
        \\Note: MOVE command is currently a placeholder
        \\
        ;
    } else if (std.mem.eql(u8, command, "PATH")) {
        return 
        \\PATH - Display or set PATH environment variable
        \\
        \\Syntax: PATH [/flags]
        \\        PATH newpath [/flags]
        \\        PATH=newpath
        \\
        \\  newpath     New PATH value to set
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: PATH C:\DOS;C:\UTILS
        \\Note: Without arguments, displays current PATH
        \\
        ;
    } else if (std.mem.eql(u8, command, "SORT")) {
        return 
        \\SORT - Sort input lines alphabetically
        \\
        \\Syntax: SORT [/flags]
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: TYPE file.txt | SORT
        \\Note: Reads from standard input and sorts lines
        \\
        ;
    } else if (std.mem.eql(u8, command, "DEL") or std.mem.eql(u8, command, "ERASE")) {
        return 
        \\DEL/ERASE - Delete files
        \\
        \\Syntax: DEL filename [/flags]
        \\        ERASE filename [/flags]
        \\
        \\  filename    File to delete
        \\
        \\Flags:
        \\  /?          Display this help message
        \\
        \\Example: DEL temp.txt
        \\Note: Wildcard deletion not yet implemented
        \\
        ;
    } else {
        return 
        \\Unknown command. Type HELP for a list of commands.
        \\
        ;
    }
}