//! CLI types: output format, include list, limit, global options, and command structure.

/// Output format for all commands.
#[derive(Debug, Clone, Default, clap::ValueEnum)]
pub enum OutputFormat {
    /// Human-readable table (default).
    #[default]
    Table,
    /// JSON output.
    Json,
    /// XML output.
    Xml,
}

/// Comma-separated list of optional content to include in transcripts.
///
/// Accepted tokens: `thinking`, `output`.
#[derive(Debug, Clone, Default)]
pub struct IncludeList {
    /// Include `thinking` blocks in transcripts.
    pub thinking: bool,
    /// Include tool `output` blocks in transcripts.
    pub output: bool,
}

impl std::str::FromStr for IncludeList {
    type Err = crate::error::AppError;

    /// Parse a comma-separated string of include tokens.
    ///
    /// Accepted tokens: `thinking`, `output`.
    /// Returns [`AppError::InvalidArg`] for any unknown token.
    fn from_str(s: &str) -> crate::error::Result<Self> {
        let mut list = IncludeList::default();
        for token in s.split(',') {
            let token = token.trim();
            if token.is_empty() {
                continue;
            }
            match token {
                "thinking" => list.thinking = true,
                "output" => list.output = true,
                other => {
                    return Err(crate::error::AppError::InvalidArg(format!(
                        "unknown include token: {other}"
                    )));
                }
            }
        }
        Ok(list)
    }
}

/// How many entries to show in list commands.
///
/// Accepts an integer (e.g. `10`) or the keyword `all` to show every entry.
#[derive(Debug, Clone)]
pub enum Limit {
    /// Show at most N entries.
    Count(usize),
    /// Show all entries without truncation.
    All,
}

impl Default for Limit {
    fn default() -> Self {
        Limit::Count(10)
    }
}

impl std::str::FromStr for Limit {
    type Err = crate::error::AppError;

    fn from_str(s: &str) -> crate::error::Result<Self> {
        if s.eq_ignore_ascii_case("all") {
            return Ok(Limit::All);
        }
        s.parse::<usize>()
            .map(Limit::Count)
            .map_err(|_| crate::error::AppError::InvalidArg(format!("invalid limit: {s}")))
    }
}

impl Limit {
    /// Apply this limit to a vector, returning a truncated or full slice.
    pub fn apply<T>(&self, items: Vec<T>) -> Vec<T> {
        match self {
            Limit::All => items,
            Limit::Count(n) => items.into_iter().take(*n).collect(),
        }
    }
}

/// Top-level CLI entry point for claudbg.
#[derive(Debug, clap::Parser)]
#[command(name = "claudbg", about = "Claude Code session inspector")]
pub struct Cli {
    /// Global options shared across all subcommands.
    #[command(flatten)]
    pub global: GlobalOpts,
    /// The subcommand to execute.
    #[command(subcommand)]
    pub command: Commands,
}

/// Global options available on every subcommand.
#[derive(Debug, Clone, clap::Args)]
pub struct GlobalOpts {
    /// Output format: table (default), json, xml.
    #[arg(long, global = true, default_value = "table")]
    pub output: OutputFormat,
    /// Show full UUIDs and extra detail.
    #[arg(long, global = true)]
    pub verbose: bool,
    /// Comma-separated list of extra content to include in transcriptions.
    /// Valid values: thinking, output. Example: --include thinking,output
    #[arg(long, global = true, default_value = "")]
    pub include: IncludeList,
    /// Force color output even when not writing to a terminal.
    #[arg(long, global = true, overrides_with = "no_color")]
    pub color: bool,
    /// Disable color output (also honored via the NO_COLOR env var).
    #[arg(long = "no-color", global = true, overrides_with = "color")]
    pub no_color: bool,
}

impl GlobalOpts {
    /// Determine whether color output should be enabled.
    ///
    /// Priority (highest → lowest):
    /// 1. `NO_COLOR` env var set to a non-empty value → disabled.
    /// 2. `--no-color` flag passed → disabled.
    /// 3. `--color` flag passed → enabled.
    /// 4. Auto-detect: enabled iff stdout is a TTY.
    pub fn color_enabled(&self) -> bool {
        use std::io::IsTerminal as _;

        // NO_COLOR spec: any non-empty value disables color.
        if std::env::var("NO_COLOR").is_ok_and(|v| !v.is_empty()) {
            return false;
        }
        if self.no_color {
            return false;
        }
        if self.color {
            return true;
        }
        std::io::stdout().is_terminal()
    }
}

/// Top-level subcommands.
#[derive(Debug, clap::Subcommand)]
pub enum Commands {
    /// List, dump, and transcribe sessions.
    #[command(subcommand_required = false)]
    Sessions {
        /// Sessions subcommand (defaults to `list` when omitted).
        #[command(subcommand)]
        cmd: Option<SessionsCmd>,
    },
    /// List, dump, and transcribe sub-agent runs.
    Agents {
        /// Agents subcommand.
        #[command(subcommand)]
        cmd: AgentsCmd,
    },
    /// Sync all session files into the local cache DB.
    Index {
        /// Force full rebuild even if files appear up to date.
        #[arg(long)]
        force: bool,
    },
    /// Launch terminal UI (coming soon).
    Tui,
    /// Run ad-hoc queries against the cache DB (coming soon).
    Query,
}

/// Subcommands for `sessions`.
#[derive(Debug, clap::Subcommand)]
pub enum SessionsCmd {
    /// List all sessions, most recent first.
    List {
        /// Maximum number of sessions to show, or "all" for no limit.
        #[arg(long, default_value = "10")]
        limit: Limit,
        /// Filter expression (may be passed multiple times; all filters are ANDed).
        /// Example: --filter 'model:haiku' --filter 'agents>0'
        #[arg(long, action = clap::ArgAction::Append)]
        filter: Vec<String>,
    },
    /// Dump raw messages from a session.
    Dump {
        /// Session ID or 8-char prefix.
        id: String,
        /// Stream new entries as the session file is written.
        #[arg(long)]
        follow: bool,
    },
    /// Show a human-readable transcript of a session.
    Transcribe {
        /// Session ID or 8-char prefix.
        id: String,
        /// Stream new entries as the session file is written.
        #[arg(long)]
        follow: bool,
    },
}

/// Subcommands for `agents`.
#[derive(Debug, clap::Subcommand)]
pub enum AgentsCmd {
    /// List all agent runs within a session.
    List {
        /// Parent session ID or 8-char prefix.
        session_id: String,
        /// Maximum number of agents to show, or "all" for no limit.
        #[arg(long, default_value = "10")]
        limit: Limit,
        /// Filter expression (may be passed multiple times; all filters are ANDed).
        /// Example: --filter 'id:abc12345'
        #[arg(long, action = clap::ArgAction::Append)]
        filter: Vec<String>,
    },
    /// Dump raw messages from an agent run.
    Dump {
        /// Parent session ID or 8-char prefix.
        session_id: String,
        /// Agent ID or 8-char prefix.
        agent_id: String,
        /// Stream new entries as the agent file is written.
        #[arg(long)]
        follow: bool,
    },
    /// Show a human-readable transcript of an agent run.
    Transcribe {
        /// Parent session ID or 8-char prefix.
        session_id: String,
        /// Agent ID or 8-char prefix.
        agent_id: String,
        /// Stream new entries as the agent file is written.
        #[arg(long)]
        follow: bool,
    },
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::str::FromStr;

    /// Empty string produces a default `IncludeList` with both flags false.
    #[test]
    fn include_list_empty_string() {
        let list = IncludeList::from_str("").unwrap();
        assert!(!list.thinking);
        assert!(!list.output);
    }

    /// Parsing `"thinking"` sets the thinking flag only.
    #[test]
    fn include_list_thinking_only() {
        let list = IncludeList::from_str("thinking").unwrap();
        assert!(list.thinking);
        assert!(!list.output);
    }

    /// Parsing `"output"` sets the output flag only.
    #[test]
    fn include_list_output_only() {
        let list = IncludeList::from_str("output").unwrap();
        assert!(!list.thinking);
        assert!(list.output);
    }

    /// Parsing `"thinking,output"` sets both flags.
    #[test]
    fn include_list_both() {
        let list = IncludeList::from_str("thinking,output").unwrap();
        assert!(list.thinking);
        assert!(list.output);
    }

    /// An unknown token returns an `AppError::InvalidArg`.
    #[test]
    fn include_list_unknown_token() {
        let result = IncludeList::from_str("images");
        assert!(result.is_err());
        let msg = result.unwrap_err().to_string();
        assert!(msg.contains("unknown include token: images"), "got: {msg}");
    }

    /// Whitespace around tokens is trimmed.
    #[test]
    fn include_list_whitespace_trim() {
        let list = IncludeList::from_str(" thinking , output ").unwrap();
        assert!(list.thinking);
        assert!(list.output);
    }

    /// `OutputFormat` defaults to `Table`.
    #[test]
    fn output_format_default() {
        let fmt = OutputFormat::default();
        assert!(matches!(fmt, OutputFormat::Table));
    }

    /// Parsing a number produces `Limit::Count`.
    #[test]
    fn limit_parse_count() {
        let limit = Limit::from_str("5").unwrap();
        assert!(matches!(limit, Limit::Count(5)));
    }

    /// Parsing `"all"` produces `Limit::All`.
    #[test]
    fn limit_parse_all() {
        let limit = Limit::from_str("all").unwrap();
        assert!(matches!(limit, Limit::All));
    }

    /// Parsing `"ALL"` (case-insensitive) also produces `Limit::All`.
    #[test]
    fn limit_parse_all_uppercase() {
        let limit = Limit::from_str("ALL").unwrap();
        assert!(matches!(limit, Limit::All));
    }

    /// Parsing an invalid string returns an error.
    #[test]
    fn limit_parse_invalid() {
        let result = Limit::from_str("banana");
        assert!(result.is_err());
    }

    /// Default limit is `Count(10)`.
    #[test]
    fn limit_default_is_ten() {
        let limit = Limit::default();
        assert!(matches!(limit, Limit::Count(10)));
    }

    /// `Limit::Count(3).apply` truncates a longer vec.
    #[test]
    fn limit_apply_count_truncates() {
        let v = vec![1, 2, 3, 4, 5];
        let result = Limit::Count(3).apply(v);
        assert_eq!(result, vec![1, 2, 3]);
    }

    /// `Limit::All.apply` returns the full vec unchanged.
    #[test]
    fn limit_apply_all_returns_all() {
        let v = vec![1, 2, 3, 4, 5];
        let result = Limit::All.apply(v);
        assert_eq!(result, vec![1, 2, 3, 4, 5]);
    }

    /// `Limit::Count(N).apply` on a shorter vec returns the full vec.
    #[test]
    fn limit_apply_count_shorter_vec_unchanged() {
        let v = vec![1, 2];
        let result = Limit::Count(10).apply(v);
        assert_eq!(result, vec![1, 2]);
    }
}