// nixos-config - My current NixOS configuration
//
// Copyright (C) 2025 Benedikt Peetz <benedikt.peetz@b-peetz.de>
// SPDX-License-Identifier: GPL-3.0-or-later
//
// This file is part of my nixos-config.
//
// You should have received a copy of the License along with this program.
// If not, see <https://www.gnu.org/licenses/gpl-3.0.txt>.

use std::{
    collections::{HashMap, HashSet},
    fs,
    str::FromStr,
};

use anyhow::{Context, Result};
use log::info;

use crate::{browser::open_in_browser, cli::InputCommand, state::State};

use super::{Input, Tag};

/// # Errors
/// When command handling fails.
///
/// # Panics
/// When internal assertions fail.
#[allow(clippy::too_many_lines)]
pub fn handle(command: InputCommand, state: &mut State) -> Result<()> {
    match command {
        InputCommand::Add { inputs } => {
            for input in inputs {
                input.commit().with_context(|| {
                    format!("Failed to add input ('{input}') to the input storage.")
                })?;
            }
        }
        InputCommand::Remove { inputs } => {
            for input in inputs {
                input.remove().with_context(|| {
                    format!("Failed to remove input ('{input}') from the input storage.")
                })?;
            }
        }
        InputCommand::File { file, tags } => {
            let file = fs::read_to_string(&file)
                .with_context(|| format!("Failed to read input file '{}'", file.display()))?;

            let mut tag_set = HashSet::with_capacity(tags.len());
            for tag in tags {
                tag_set.insert(tag);
            }

            for line in file.lines().map(str::trim) {
                if line.is_empty() {
                    continue;
                }

                let mut input = Input::from_str(line)?;
                input.tags = input.tags.union(&tag_set).cloned().collect();

                input.commit().with_context(|| {
                    format!("Failed to add input ('{input}') to the input storage.")
                })?;
            }
        }
        InputCommand::Review { project } => {
            'outer: for all in Input::all()?.chunks(100) {
                info!("Starting review for the first hundred URLs.");

                for input in all {
                    info!("-> '{input}'");
                    open_in_browser(&project, state, Some(input.url.clone()))?;
                }

                {
                    use std::io::{stdin, stdout, Write};

                    let mut s = String::new();
                    eprint!("Continue? (y/N) ");
                    stdout().flush()?;

                    stdin()
                        .read_line(&mut s)
                        .expect("Did not enter a correct string");

                    if let Some('\n') = s.chars().next_back() {
                        s.pop();
                    }
                    if let Some('\r') = s.chars().next_back() {
                        s.pop();
                    }

                    if s != "y" {
                        break 'outer;
                    }
                }
            }
        }
        InputCommand::List { tags } => {
            let mut tag_set = HashSet::with_capacity(tags.len());
            for tag in tags {
                tag_set.insert(tag);
            }

            for url in Input::all()?
                .iter()
                .filter(|input| tag_set.is_subset(&input.tags))
            {
                println!("{url}");
            }
        }
        InputCommand::Tags {} => {
            let mut without_tags = 0;
            let mut tag_set: HashMap<Tag, u64> = HashMap::new();

            for input in Input::all()? {
                if input.tags.is_empty() {
                    without_tags += 1;
                }

                for tag in input.tags {
                    if let Some(number) = tag_set.get_mut(&tag) {
                        *number += 1;
                    } else {
                        tag_set.insert(tag, 1);
                    }
                }
            }

            let mut tags: Vec<(Tag, u64)> = tag_set.into_iter().collect();
            tags.sort_by_key(|(_, number)| *number);
            tags.reverse();

            for (tag, number) in tags {
                println!("{tag} {number}");
            }

            if without_tags != 0 {
                println!();
                println!("Witohut tags: {without_tags}");
            }
        }
    }
    Ok(())
}