//! `issue-edit <number> [--title <t>] [body sources] [--state s]
//! [--milestone id] [repo]` — partial update of an issue. Fields not
//! provided are left unchanged.

use anyhow::Result;
use clap::{Args as ClapArgs, ValueEnum};
use forgejo_api::structs::EditIssueOption;
use serde_json::json;

use crate::body;
use crate::client::{Client, index};
use crate::verbs::print_json;

#[derive(Copy, Clone, ValueEnum)]
pub enum StateArg {
    Open,
    Closed,
}

impl StateArg {
    fn as_str(self) -> &'static str {
        match self {
            Self::Open => "open",
            Self::Closed => "closed",
        }
    }
}

#[derive(ClapArgs)]
pub struct Args {
    /// Issue number.
    number: u64,
    /// New title (omit to leave unchanged).
    #[arg(long)]
    title: Option<String>,
    /// Inline body text (omit to leave unchanged).
    #[arg(long, conflicts_with = "body_file")]
    body: Option<String>,
    /// Read body from a file. `-` means stdin.
    #[arg(long = "body-file")]
    body_file: Option<String>,
    /// New state.
    #[arg(long, value_enum)]
    state: Option<StateArg>,
    /// Milestone id (0 to unset).
    #[arg(long)]
    milestone: Option<u64>,
}

/// # Errors
///
/// Propagates any I/O error from the body input (`--body-file`,
/// stdin), any transport error from the Forgejo REST call (network
/// unreachable, 4xx/5xx response, token missing/invalid), and any
/// I/O error from writing the response to stdout.
pub fn run(client: &Client, args: Args) -> Result<()> {
    // Body is partial: only update the body field if a source was
    // actually given. Piped stdin without --body/--body-file leaves
    // body alone (the partial-update contract). Absent fields ride as
    // JSON `null`, which Forgejo's partial-update binding treats as
    // "leave unchanged".
    let body_explicit = args.body.is_some() || args.body_file.is_some();
    let body = if body_explicit {
        body::resolve(args.body.as_deref(), args.body_file.as_deref())?
    } else {
        None
    };

    let payload = EditIssueOption {
        assignee: None,
        assignees: None,
        body,
        due_date: None,
        milestone: args.milestone.map(index).transpose()?,
        r#ref: None,
        state: args.state.map(|s| s.as_str().to_owned()),
        title: args.title,
        unset_due_date: None,
        updated_at: None,
    };

    let (owner, name) = client.owner_repo()?;
    let resp = client
        .api()
        .issue_edit_issue(owner, name, index(args.number)?, payload)
        .send()?;
    print_json(&json!({
        "number": resp.number,
        "title": resp.title,
        "state": resp.state,
        "milestone": resp.milestone.as_ref().and_then(|m| m.title.as_deref()),
    }))
}