//! `pic plan [--file picloud.toml]` — diff the manifest's desired state
//! against the live app and print the per-resource changes. Read-only:
//! builds a bundle (manifest + script sources) and POSTs it to the
//! server's plan endpoint, which computes the diff.

use std::path::Path;

use anyhow::{Context, Result};
use serde::Serialize;
use serde_json::{json, Map, Value};

use crate::client::{ChangeDto, Client, PlanDto};
use crate::config;
use crate::manifest::Manifest;
use crate::output::{OutputMode, Table};

pub async fn run(manifest_path: &Path, env: Option<&str>, mode: OutputMode) -> Result<()> {
    let creds = config::resolve()?;
    let client = Client::from_creds(&creds)?;

    let manifest = Manifest::load_with_env(manifest_path, env)?;
    let base_dir = manifest_path.parent().unwrap_or_else(|| Path::new("."));
    let bundle = build_bundle(&manifest, base_dir)?;

    let plan = client.plan(&manifest.app.slug, &bundle).await?;
    // Record the bound-plan token so a subsequent `pic apply` can detect the
    // app changing underneath the reviewed plan (best-effort — a read-only
    // plan still succeeds if the project dir isn't writable).
    if !plan.state_token.is_empty() {
        if let Err(e) =
            crate::linkstate::write_plan(base_dir, &manifest.app.slug, &plan.state_token)
        {
            eprintln!("warning: could not record plan state for `pic apply`: {e}");
        }
    }
    render(&plan, mode);
    Ok(())
}

/// Assemble the wire bundle: scripts carry inlined source (read from
/// their `file`), routes pass through, triggers flatten into a tagged
/// array, secrets are names only.
pub fn build_bundle(manifest: &Manifest, base_dir: &Path) -> Result<Value> {
    let mut scripts = Vec::with_capacity(manifest.scripts.len());
    for s in &manifest.scripts {
        let source = std::fs::read_to_string(base_dir.join(&s.file))
            .with_context(|| format!("reading script source {}", s.file))?;
        let mut obj = Map::new();
        obj.insert("name".into(), json!(s.name));
        obj.insert("source".into(), json!(source));
        obj.insert("kind".into(), serde_json::to_value(s.kind)?);
        if let Some(d) = &s.description {
            obj.insert("description".into(), json!(d));
        }
        if let Some(t) = s.timeout_seconds {
            obj.insert("timeout_seconds".into(), json!(t));
        }
        if let Some(m) = s.memory_limit_mb {
            obj.insert("memory_limit_mb".into(), json!(m));
        }
        if let Some(sb) = &s.sandbox {
            obj.insert("sandbox".into(), serde_json::to_value(sb)?);
        }
        obj.insert("enabled".into(), json!(s.enabled));
        scripts.push(Value::Object(obj));
    }

    let routes = manifest
        .routes
        .iter()
        .map(serde_json::to_value)
        .collect::<Result<Vec<_>, _>>()?;

    let t = &manifest.triggers;
    let mut triggers = Vec::new();
    for s in &t.kv {
        triggers.push(tagged("kv", s)?);
    }
    for s in &t.docs {
        triggers.push(tagged("docs", s)?);
    }
    for s in &t.files {
        triggers.push(tagged("files", s)?);
    }
    for s in &t.cron {
        triggers.push(tagged("cron", s)?);
    }
    for s in &t.pubsub {
        triggers.push(tagged("pubsub", s)?);
    }
    for s in &t.email {
        triggers.push(tagged("email", s)?);
    }
    for s in &t.queue {
        triggers.push(tagged("queue", s)?);
    }

    // Vars: key → JSON value. TOML values round-trip to JSON via serde so the
    // wire shape matches the server's `serde_json::Value`.
    let mut vars = Map::new();
    for (k, v) in &manifest.vars {
        vars.insert(
            k.clone(),
            serde_json::to_value(v).with_context(|| format!("encoding var `{k}`"))?,
        );
    }

    Ok(json!({
        "scripts": scripts,
        "routes": routes,
        "triggers": triggers,
        "secrets": manifest.secrets.names,
        "vars": vars,
    }))
}

/// Serialize a trigger spec and stamp its `kind` discriminator.
fn tagged(kind: &str, spec: impl Serialize) -> Result<Value> {
    let mut v = serde_json::to_value(spec)?;
    if let Value::Object(map) = &mut v {
        map.insert("kind".into(), Value::String(kind.to_string()));
    }
    Ok(v)
}

fn render(plan: &PlanDto, mode: OutputMode) {
    let mut table = Table::new(["kind", "op", "resource", "detail"]);
    let groups: [(&str, &Vec<ChangeDto>); 5] = [
        ("script", &plan.scripts),
        ("route", &plan.routes),
        ("trigger", &plan.triggers),
        ("secret", &plan.secrets),
        ("var", &plan.vars),
    ];
    for (kind, changes) in groups {
        for c in changes {
            table.row([
                kind.to_string(),
                c.op.clone(),
                c.key.clone(),
                c.detail.clone().unwrap_or_default(),
            ]);
        }
    }
    table.print(mode);
}