module cli

import time

fn man_flag() Flag {
    return Flag{
        flag: .bool
        name: 'man'
        description: 'Prints the auto-generated manpage.'
    }
}

fn man_cmd() Command {
    return Command{
        name: 'man'
        usage: '<subcommand>'
        description: 'Prints the auto-generated manpage.'
        execute: print_manpage_for_command
    }
}

// print_manpage_for_command prints the manpage for the
// command or subcommand in `man_cmd` to stdout
pub fn print_manpage_for_command(man_cmd Command) ! {
    if man_cmd.args.len > 0 {
        mut cmd := man_cmd.parent
        for arg in man_cmd.args {
            mut found := false
            for sub_cmd in cmd.commands {
                if sub_cmd.name == arg {
                    cmd = unsafe { &sub_cmd }
                    found = true
                    break
                }
            }
            if !found {
                args := man_cmd.args.join(' ')
                println('Invalid command: ${args}')
                return
            }
        }
        print(cmd.manpage())
    } else {
        if unsafe { man_cmd.parent != 0 } {
            print(man_cmd.parent.manpage())
        }
    }
}

// manpage returns a `string` containing the mdoc(7) manpage for
// this `Command`
pub fn (cmd Command) manpage() string {
    mut mdoc := '.Dd ${time.now().strftime('%B %d, %Y')}\n'
    mdoc += '.Dt ${cmd.full_name().replace(' ', '-').to_upper()} 1\n'
    mdoc += '.Os\n.Sh NAME\n.Nm ${cmd.full_name().replace(' ', '-')}\n.Nd ${cmd.description}\n'
    mdoc += '.Sh SYNOPSIS\n'
    mdoc += '.Nm ${cmd.root().name}\n'
    if unsafe { cmd.parent != 0 } {
        mut parents := []Command{}
        if !cmd.parent.is_root() {
            parents.prepend(cmd.parent)
            for {
                p := parents[0]
                if p.parent.is_root() {
                    break
                } else {
                    parents.prepend(p.parent)
                }
            }
            for c in parents {
                mdoc += '.Ar ${c.name}\n'
            }
        }
        mdoc += '.Ar ${cmd.name}\n'
    }
    for flag in cmd.flags {
        mdoc += '.Op'
        if flag.abbrev != '' {
            mdoc += ' Fl ${flag.abbrev}'
        } else {
            if cmd.posix_mode {
                mdoc += ' Fl -${flag.name}'
            } else {
                mdoc += ' Fl ${flag.name}'
            }
        }
        match flag.flag {
            .int, .float, .int_array, .float_array { mdoc += ' Ar num' }
            .string, .string_array { mdoc += ' Ar string' }
            else {}
        }
        mdoc += '\n'
    }
    for i in 0 .. cmd.required_args {
        mdoc += '.Ar arg${i}\n'
    }
    if cmd.commands.len > 0 {
        mdoc += '.Nm ${cmd.root().name}\n'
        if unsafe { cmd.parent != 0 } {
            mut parents := []Command{}
            if !cmd.parent.is_root() {
                parents.prepend(cmd.parent)
                for {
                    p := parents[0]
                    if p.parent.is_root() {
                        break
                    } else {
                        parents.prepend(p.parent)
                    }
                }
                for c in parents {
                    mdoc += '.Ar ${c.name}\n'
                }
            }
            mdoc += '.Ar ${cmd.name}\n'
        }
        mdoc += '.Ar subcommand\n'
    }

    mdoc += '.Sh DESCRIPTION\n'
    if cmd.man_description != '' {
        mdoc += '${cmd.man_description}\n'
    } else if cmd.description != '' {
        mdoc += '${cmd.description}\n'
    }
    if cmd.flags.len > 0 {
        mdoc += '.Pp\nThe options are as follows:\n'
        mdoc += '.Bl -tag -width indent\n'
        for flag in cmd.flags {
            mdoc += '.It'
            if flag.abbrev != '' {
                mdoc += ' Fl ${flag.abbrev}'
            }
            if cmd.posix_mode {
                mdoc += ' Fl -${flag.name}'
            } else {
                mdoc += ' Fl ${flag.name}'
            }
            mdoc += '\n'
            if flag.description != '' {
                mdoc += '${flag.description}\n'
            }
        }
        mdoc += '.El\n'
    }
    if cmd.commands.len > 0 {
        mdoc += '.Pp\nThe subcommands are as follows:\n'
        mdoc += '.Bl -tag -width indent\n'
        for c in cmd.commands {
            mdoc += '.It Cm ${c.name}\n'
            if c.description != '' {
                mdoc += '${c.description}\n'
            }
        }
        mdoc += '.El\n'
    }

    if cmd.commands.len > 0 {
        mdoc += '.Sh SEE ALSO\n'
        mut cmds := []string{}
        if unsafe { cmd.parent != 0 } {
            cmds << cmd.parent.full_name().replace(' ', '-')
        }
        for c in cmd.commands {
            cmds << c.full_name().replace(' ', '-')
        }
        cmds.sort()
        mut i := 1
        for c in cmds {
            mdoc += '.Xr ${c} 1'
            if i == cmds.len {
                mdoc += '\n'
            } else {
                mdoc += ' ,\n'
            }
            i++
        }
    }

    return mdoc
}