zlayer-toolchain 0.14.3

//! Chocolatey `.nupkg` → [`InstallPlan`] parser.
//!
//! A `.nupkg` is a zip archive. This module parses the root `*.nuspec`
//! (package `<id>` / `<version>`) plus `tools/chocolateyInstall.ps1` into the
//! SAME [`InstallPlan`] type the Homebrew recipe parser ([`crate::recipe`])
//! produces, so one executor runs both.
//!
//! The `chocolateyInstall.ps1` scan is line-oriented and deliberately
//! conservative — PowerShell is a full language, so every construct the
//! scanner does not fully understand becomes an
//! [`InstallStep::Unsupported`] carrying the source text (the same contract as
//! the Homebrew parser: never silently swallow a line). Supported idioms:
//!
//! - `$var = 'literal'` / `"interpolated $var"` assignments, including the
//!   `"$(Split-Path -Parent $MyInvocation.MyCommand.Definition)"` tools-dir
//!   idiom (maps to the install prefix) and simple `Join-Path a b`.
//! - Hashtable splats — `$packageArgs = @{ url = '...'; ... }` followed by
//!   `Install-ChocolateyZipPackage @packageArgs` — the dominant modern idiom.
//! - `Install-ChocolateyZipPackage` (splat, named `-Url`/`-Url64bit`, or
//!   positional) → download the zip ([`ResourceSpec`] +
//!   [`InstallStep::StageResource`]) and extract into the prefix
//!   ([`InstallStep::PrefixInstall`] from `"."`).
//! - `Get-ChocolateyWebFile` → download only (resource + stage).
//! - `Install-BinFile -Name x -Path y` → [`InstallStep::BinInstall`].
//! - `Install-ChocolateyPackage` / `Install-ChocolateyInstallPackage` (exe/msi
//!   installers), `Start-ChocolateyProcessAsAdmin`, registry cmdlets,
//!   `Set-EnvironmentVariable`, and anything else opaque → `Unsupported` (the
//!   Windows resolver routes those packages to the loud choco container).
//!
//! 64-bit `url64`/`checksum64` are preferred when present (we target
//! amd64/arm64 Windows). A checksum whose type is not sha256 (md5/sha1) keeps
//! the URL but yields an EMPTY `sha256` plus an `Unsupported` marker
//! (`checksumType <t>`), so callers know verification is weaker.

use std::collections::HashMap;
use std::io::Read;
use std::path::Path;

use crate::error::{Result, ToolchainError};
use crate::recipe::{InstallPlan, InstallStep, ResourceSpec};

/// A parsed Chocolatey package: nuspec identity plus the executable plan.
#[derive(Debug, Clone, PartialEq)]
pub struct ChocoRecipe {
    /// Package `<id>` from the nuspec (e.g. `terraform`).
    pub id: String,
    /// Package `<version>` from the nuspec (e.g. `1.16.0`).
    pub version: String,
    /// The install plan parsed from `tools/chocolateyInstall.ps1`.
    pub plan: InstallPlan,
}

/// Parse an in-memory `.nupkg` into a [`ChocoRecipe`] against `prefix` (the
/// toolchain install prefix — Chocolatey's "tools dir" maps to it).
///
/// # Errors
///
/// Returns [`ToolchainError::RegistryError`] when `bytes` is not a zip, when
/// the archive has no root `*.nuspec` (or it lacks `<id>`/`<version>`), or
/// when `tools/chocolateyInstall.ps1` is missing.
pub fn parse_nupkg(bytes: &[u8], prefix: &Path) -> Result<ChocoRecipe> {
    let cursor = std::io::Cursor::new(bytes);
    let mut archive = zip::ZipArchive::new(cursor).map_err(|e| ToolchainError::RegistryError {
        message: format!("failed to open .nupkg as a zip archive: {e}"),
    })?;
    let names: Vec<String> = archive.file_names().map(str::to_string).collect();
    let nuspec_name = names
        .iter()
        .find(|n| is_root_nuspec(n))
        .cloned()
        .ok_or_else(|| ToolchainError::RegistryError {
            message: "no *.nuspec found at the .nupkg archive root".to_string(),
        })?;
    let nuspec = read_zip_text(&mut archive, &nuspec_name)?;
    let (id, version) = parse_nuspec(&nuspec)?;
    let ps1_name = names
        .iter()
        .find(|n| is_install_ps1(n))
        .cloned()
        .ok_or_else(|| ToolchainError::RegistryError {
            message: format!("no tools/chocolateyInstall.ps1 in .nupkg for {id}"),
        })?;
    let ps1 = read_zip_text(&mut archive, &ps1_name)?;
    let plan = plan_from_ps1(&ps1, &id, &version, prefix);
    Ok(ChocoRecipe { id, version, plan })
}

/// `true` for a `*.nuspec` entry at the archive root (no directory part).
fn is_root_nuspec(name: &str) -> bool {
    !name.contains('/')
        && !name.contains('\\')
        && Path::new(&name.to_ascii_lowercase())
            .extension()
            .is_some_and(|e| e == "nuspec")
}

/// `true` for the `tools/chocolateyInstall.ps1` entry (case-insensitive,
/// either slash direction).
fn is_install_ps1(name: &str) -> bool {
    name.to_ascii_lowercase().replace('\\', "/") == "tools/chocolateyinstall.ps1"
}

/// Read one archive entry as text (lossy UTF-8, BOM stripped).
fn read_zip_text(
    archive: &mut zip::ZipArchive<std::io::Cursor<&[u8]>>,
    name: &str,
) -> Result<String> {
    let mut file = archive
        .by_name(name)
        .map_err(|e| ToolchainError::RegistryError {
            message: format!("failed to read `{name}` from .nupkg: {e}"),
        })?;
    let mut bytes = Vec::new();
    file.read_to_end(&mut bytes)?;
    let text = String::from_utf8_lossy(&bytes).into_owned();
    Ok(text.trim_start_matches('\u{feff}').to_string())
}

// ---------------------------------------------------------------------------
// .nuspec scanning (no XML dependency — lightweight tag scan)
// ---------------------------------------------------------------------------

/// Extract `<id>` and `<version>` from nuspec XML, honoring the `<metadata>`
/// nesting and tolerating attributes/whitespace on the tags.
fn parse_nuspec(xml: &str) -> Result<(String, String)> {
    let meta = xml_region(xml, "metadata").unwrap_or(xml);
    let id = xml_region(meta, "id")
        .map(str::trim)
        .filter(|s| !s.is_empty());
    let version = xml_region(meta, "version")
        .map(str::trim)
        .filter(|s| !s.is_empty());
    match (id, version) {
        (Some(id), Some(version)) => Ok((id.to_string(), version.to_string())),
        _ => Err(ToolchainError::RegistryError {
            message: "nuspec is missing <id> or <version> inside <metadata>".to_string(),
        }),
    }
}

/// Inner text of the first `<tag ...> ... </tag>` region (case-insensitive,
/// attribute-tolerant; self-closing tags are skipped).
fn xml_region<'a>(xml: &'a str, tag: &str) -> Option<&'a str> {
    let lower = xml.to_ascii_lowercase();
    let open = format!("<{tag}");
    let close = format!("</{tag}");
    let mut search = 0;
    while let Some(rel) = lower[search..].find(&open) {
        let after = search + rel + open.len();
        if !matches!(
            lower.as_bytes().get(after),
            Some(b'>' | b' ' | b'\t' | b'\r' | b'\n')
        ) {
            search = after;
            continue;
        }
        let gt = lower[after..].find('>')? + after;
        if lower.as_bytes()[gt - 1] == b'/' {
            search = gt + 1;
            continue; // self-closing tag
        }
        let end = lower[gt + 1..].find(&close)? + gt + 1;
        return Some(&xml[gt + 1..end]);
    }
    None
}

// ---------------------------------------------------------------------------
// chocolateyInstall.ps1 scanning
// ---------------------------------------------------------------------------

/// A download picked from a command's arguments (64-bit preferred).
struct Download {
    /// Download URL.
    url: String,
    /// sha256 (bare hex) — empty when the checksum is missing or non-sha256.
    sha256: String,
    /// Weak-verification marker to surface as `Unsupported`, when applicable.
    weak: Option<String>,
}

/// Line-oriented planner state for one `chocolateyInstall.ps1`.
struct PsPlanner {
    /// Package id (resource naming + choco's injected `$packageName`).
    pkg_id: String,
    /// Install prefix as a display string (the "tools dir").
    prefix: String,
    /// Resolved `$var` values, keyed by lowercased name.
    vars: HashMap<String, String>,
    /// Parsed `@{...}` hashtables, keyed by lowercased variable name. Values
    /// are `None` when the entry's RHS could not be resolved.
    tables: HashMap<String, HashMap<String, Option<String>>>,
    /// Accumulated plan steps.
    steps: Vec<InstallStep>,
    /// Accumulated download resources.
    resources: Vec<ResourceSpec>,
}

/// Parse a `chocolateyInstall.ps1` into an [`InstallPlan`]. Pure (no IO);
/// unknown constructs land as [`InstallStep::Unsupported`].
fn plan_from_ps1(ps1: &str, id: &str, version: &str, prefix: &Path) -> InstallPlan {
    let mut planner = PsPlanner::new(id, version, prefix);
    let lines: Vec<&str> = ps1.lines().collect();
    let mut i = 0usize;
    while i < lines.len() {
        let raw = lines[i].trim_start_matches('\u{feff}').trim();
        i += 1;
        if raw.starts_with("<#") {
            // Block comment: consume through the closing `#>`.
            let mut cur = raw;
            while !cur.contains("#>") && i < lines.len() {
                cur = lines[i];
                i += 1;
            }
            continue;
        }
        let line = strip_ps_comment(raw);
        let line = line.trim();
        if line.is_empty() {
            continue;
        }
        planner.dispatch_line(line, &lines, &mut i);
    }
    planner.finish()
}

impl PsPlanner {
    /// Fresh planner seeded with choco's script-scope injected variables
    /// (`$packageName`, `$packageVersion`, `$packageFolder`).
    fn new(id: &str, version: &str, prefix: &Path) -> Self {
        let prefix = prefix.display().to_string();
        let mut vars = HashMap::new();
        vars.insert("packagename".to_string(), id.to_string());
        vars.insert("packageversion".to_string(), version.to_string());
        vars.insert("packagefolder".to_string(), prefix.clone());
        Self {
            pkg_id: id.to_string(),
            prefix,
            vars,
            tables: HashMap::new(),
            steps: Vec::new(),
            resources: Vec::new(),
        }
    }

    /// Record an unsupported construct.
    fn unsupported(&mut self, construct: &str) {
        self.steps.push(InstallStep::Unsupported {
            construct: construct.to_string(),
        });
    }

    /// Record an unsupported line; when it opens a `{` block, consume the
    /// whole block so the region folds into ONE `Unsupported` step.
    fn unsupported_block(&mut self, line: &str, lines: &[&str], i: &mut usize) {
        self.unsupported(line);
        let mut delta = line_brace_delta(line);
        while delta > 0 && *i < lines.len() {
            let next = strip_ps_comment(lines[*i].trim());
            *i += 1;
            delta += line_brace_delta(&next);
        }
    }

    /// Dispatch one logical line: assignment, inert, or command.
    fn dispatch_line(&mut self, line: &str, lines: &[&str], i: &mut usize) {
        if let Some((name, rhs)) = parse_assignment(line) {
            self.assignment(line, &name, rhs, lines, i);
            return;
        }
        if is_inert(line) {
            return;
        }
        let tokens = tokenize_ps(line);
        let Some(cmd) = tokens.first().cloned() else {
            return;
        };
        match cmd.to_ascii_lowercase().as_str() {
            "install-chocolateyzippackage" => self.cmd_zip_package(&tokens[1..], line),
            "get-chocolateywebfile" => self.cmd_web_file(&tokens[1..], line),
            "install-chocolateypackage" | "install-chocolateyinstallpackage" => {
                self.cmd_loud_installer(&cmd, &tokens[1..], line);
            }
            "install-binfile" => self.cmd_bin_file(&tokens[1..], line),
            _ => self.unsupported_block(line, lines, i),
        }
    }

    /// Handle a `$name = <rhs>` assignment (hashtable or scalar).
    fn assignment(&mut self, line: &str, name: &str, rhs: &str, lines: &[&str], i: &mut usize) {
        if name == "erroractionpreference" {
            return; // inert
        }
        if let Some(after_brace) = rhs.strip_prefix("@{") {
            match collect_hashtable_body(after_brace, lines, i) {
                Some(body) => {
                    let (map, junk) = self.parse_table(&body);
                    for entry in junk {
                        self.unsupported(&entry);
                    }
                    self.tables.insert(name.to_string(), map);
                }
                None => self.unsupported(line),
            }
            return;
        }
        match self.resolve_rhs(rhs) {
            Some(value) => {
                self.vars.insert(name.to_string(), value);
            }
            None => self.unsupported_block(line, lines, i),
        }
    }

    /// Parse a hashtable body into (entries, junk-lines). Entry values that do
    /// not resolve are recorded as `None` (the consuming command decides).
    fn parse_table(&self, body: &str) -> (HashMap<String, Option<String>>, Vec<String>) {
        let mut map = HashMap::new();
        let mut junk = Vec::new();
        for line in body.lines() {
            for entry in split_semis(line) {
                let entry = entry.trim();
                if entry.is_empty() {
                    continue;
                }
                match split_kv(entry) {
                    Some((key, value)) => {
                        map.insert(normalize_key(key), self.resolve_rhs(value));
                    }
                    None => junk.push(entry.to_string()),
                }
            }
        }
        (map, junk)
    }

    // -- commands -------------------------------------------------------------

    /// `Install-ChocolateyZipPackage` → download the zip + extract into the
    /// prefix (`StageResource` + `PrefixInstall { from: ".", to: None }`).
    fn cmd_zip_package(&mut self, args: &[String], line: &str) {
        let args =
            self.gather_call_args(args, &["packagename", "url", "unziplocation", "url64bit"]);
        match pick_download(&args) {
            Some(dl) => self.push_download(dl, true),
            None => self.unsupported(line),
        }
    }

    /// `Get-ChocolateyWebFile` → download only (the file lands in the tools
    /// dir, i.e. the prefix).
    fn cmd_web_file(&mut self, args: &[String], line: &str) {
        let args = self.gather_call_args(args, &["packagename", "filefullpath", "url", "url64bit"]);
        match pick_download(&args) {
            Some(dl) => self.push_download(dl, false),
            None => self.unsupported(line),
        }
    }

    /// `Install-ChocolateyPackage` / `Install-ChocolateyInstallPackage` —
    /// exe/msi installers cannot run outside HCS-with-net; surface as
    /// `Unsupported` (the resolver routes these to the loud choco container).
    fn cmd_loud_installer(&mut self, cmd: &str, args: &[String], line: &str) {
        let args = self.gather_call_args(args, &["packagename", "filetype", "silentargs", "url"]);
        let url = args
            .get("url64bit")
            .or_else(|| args.get("url"))
            .and_then(Clone::clone);
        let construct = url.map_or_else(|| line.to_string(), |u| format!("{cmd} {u}"));
        self.unsupported(&construct);
    }

    /// `Install-BinFile -Name x -Path y` → [`InstallStep::BinInstall`].
    fn cmd_bin_file(&mut self, args: &[String], line: &str) {
        let args = self.gather_call_args(args, &["name", "path"]);
        let name = args.get("name").and_then(Clone::clone);
        let path = args.get("path").and_then(Clone::clone);
        match (name, path) {
            (Some(name), Some(path)) => {
                let from = self.relativize(&path);
                self.steps.push(InstallStep::BinInstall {
                    from,
                    to: Some(name),
                });
            }
            _ => self.unsupported(line),
        }
    }

    /// Push a picked download: resource + stage (+ extract-into-prefix for zip
    /// packages) (+ weak-checksum marker when verification is degraded).
    fn push_download(&mut self, dl: Download, extract_to_prefix: bool) {
        let name = self.unique_resource_name();
        self.resources.push(ResourceSpec {
            name: name.clone(),
            url: dl.url,
            sha256: dl.sha256,
            stage_to: None,
        });
        self.steps
            .push(InstallStep::StageResource { name, dir: None });
        if extract_to_prefix {
            self.steps.push(InstallStep::PrefixInstall {
                from: ".".to_string(),
                to: None,
            });
        }
        if let Some(weak) = dl.weak {
            self.unsupported(&weak);
        }
    }

    /// First free resource name: the package id, then `<id>-2`, `<id>-3`, ...
    fn unique_resource_name(&self) -> String {
        let taken = |candidate: &str| self.resources.iter().any(|r| r.name == candidate);
        if !taken(&self.pkg_id) {
            return self.pkg_id.clone();
        }
        let mut n = 2usize;
        loop {
            let candidate = format!("{}-{n}", self.pkg_id);
            if !taken(&candidate) {
                return candidate;
            }
            n += 1;
        }
    }

    /// Merge splatted tables, `-Named` parameters, and positional arguments
    /// into one lowercased-key argument map.
    fn gather_call_args(
        &self,
        tokens: &[String],
        positional: &[&str],
    ) -> HashMap<String, Option<String>> {
        let mut out = HashMap::new();
        let mut pos_idx = 0usize;
        let mut k = 0usize;
        while k < tokens.len() {
            let tok = &tokens[k];
            k += 1;
            if let Some(splat) = tok.strip_prefix('@') {
                if let Some(table) = self.tables.get(&splat.to_ascii_lowercase()) {
                    for (key, value) in table {
                        out.insert(key.clone(), value.clone());
                    }
                }
                continue;
            }
            if let Some(param) = tok.strip_prefix('-') {
                let value = if k < tokens.len() && !tokens[k].starts_with('-') {
                    let v = self.resolve_rhs(&tokens[k]);
                    k += 1;
                    v
                } else {
                    Some("true".to_string()) // bare switch
                };
                out.insert(normalize_key(param), value);
                continue;
            }
            if pos_idx < positional.len() {
                out.insert(positional[pos_idx].to_string(), self.resolve_rhs(tok));
                pos_idx += 1;
            }
        }
        out
    }

    // -- value resolution -------------------------------------------------------

    /// Resolve a value expression: quoted literals (with interpolation), known
    /// `$vars`, the `Split-Path ... $MyInvocation...` tools-dir idiom, simple
    /// `Join-Path a b`, and bare single-word literals. `None` = unresolvable.
    fn resolve_rhs(&self, rhs: &str) -> Option<String> {
        let rhs = rhs.trim();
        if let Some(v) = full_single_quoted(rhs) {
            return Some(v);
        }
        if let Some(body) = full_double_quoted(rhs) {
            return self.interp_dquote(body);
        }
        if let Some(v) = self.split_path_value(rhs) {
            return Some(v);
        }
        let lower = rhs.to_ascii_lowercase();
        if lower.starts_with("join-path ") {
            let toks = tokenize_ps(&rhs["join-path ".len()..]);
            if let [a, b] = toks.as_slice() {
                let a = self.resolve_rhs(a)?;
                let b = self.resolve_rhs(b)?;
                return Some(format!("{}/{b}", a.trim_end_matches(['/', '\\'])));
            }
            return None;
        }
        if let Some(inner) = rhs.strip_prefix("$(").and_then(|r| r.strip_suffix(')')) {
            return self.resolve_subexpr(inner);
        }
        if let Some(name) = rhs.strip_prefix('$') {
            if is_ident(name) {
                return self.lookup(name);
            }
            return None;
        }
        // Bare single-word literal (e.g. an unquoted `sha256`). A word with a
        // `-` is likely a cmdlet (`Get-PackageParameters`) — reject those.
        if !rhs.is_empty()
            && !rhs.contains(char::is_whitespace)
            && !rhs.contains('-')
            && !rhs.starts_with('@')
            && !rhs.starts_with('(')
        {
            return Some(rhs.to_string());
        }
        None
    }

    /// Resolve a double-quoted string body: backtick escapes, `$(...)`
    /// subexpressions, `${name}` and `$name` interpolations.
    fn interp_dquote(&self, body: &str) -> Option<String> {
        let mut out = String::new();
        let bytes = body.as_bytes();
        let mut i = 0usize;
        while i < body.len() {
            let c = body[i..].chars().next()?;
            if c == '`' {
                i += 1;
                if let Some(next) = body[i..].chars().next() {
                    out.push(next);
                    i += next.len_utf8();
                }
                continue;
            }
            if c != '$' {
                out.push(c);
                i += c.len_utf8();
                continue;
            }
            i += 1;
            if bytes.get(i) == Some(&b'(') {
                let close = find_matching_paren(&body[i..])?;
                out.push_str(&self.resolve_subexpr(&body[i + 1..i + close])?);
                i += close + 1;
            } else if bytes.get(i) == Some(&b'{') {
                let end = body[i..].find('}')? + i;
                out.push_str(&self.lookup(&body[i + 1..end])?);
                i = end + 1;
            } else {
                let start = i;
                while i < body.len() && is_ident_byte(bytes[i]) {
                    i += 1;
                }
                if i == start {
                    out.push('$'); // lone `$`
                    continue;
                }
                if bytes.get(i) == Some(&b':') {
                    return None; // scoped/env variable (`$env:X`) — opaque
                }
                out.push_str(&self.lookup(&body[start..i])?);
            }
        }
        Some(out)
    }

    /// Resolve a `$(...)` subexpression: the `Split-Path` tools-dir idiom or a
    /// plain variable reference.
    fn resolve_subexpr(&self, inner: &str) -> Option<String> {
        let inner = inner.trim();
        if let Some(v) = self.split_path_value(inner) {
            return Some(v);
        }
        inner
            .strip_prefix('$')
            .filter(|name| is_ident(name))
            .and_then(|name| self.lookup(name))
    }

    /// The `Split-Path [-Parent] $MyInvocation.MyCommand.Definition` idiom →
    /// the package tools dir → our install prefix.
    fn split_path_value(&self, expr: &str) -> Option<String> {
        let lower = expr.to_ascii_lowercase();
        (lower.starts_with("split-path") && lower.contains("$myinvocation.mycommand.definition"))
            .then(|| self.prefix.clone())
    }

    /// Case-insensitive variable lookup.
    fn lookup(&self, name: &str) -> Option<String> {
        self.vars.get(&name.to_ascii_lowercase()).cloned()
    }

    /// Make a path relative to the prefix (tools dir) when it lives under it.
    fn relativize(&self, path: &str) -> String {
        path.strip_prefix(&self.prefix).map_or_else(
            || path.to_string(),
            |rest| {
                let rest = rest.trim_start_matches(['/', '\\']);
                if rest.is_empty() {
                    ".".to_string()
                } else {
                    rest.to_string()
                }
            },
        )
    }

    /// Build the final plan (no patches/env in the choco path).
    fn finish(self) -> InstallPlan {
        InstallPlan {
            steps: self.steps,
            resources: self.resources,
            patches: Vec::new(),
            env: HashMap::new(),
            deparallelize: false,
        }
    }
}

// ---------------------------------------------------------------------------
// Download picking / checksum classification
// ---------------------------------------------------------------------------

/// Pick the download from gathered args: `url64bit` (with `checksum64`,
/// falling back to `checksumType` per choco's defaulting) preferred over
/// `url`. `None` when no URL resolved.
fn pick_download(args: &HashMap<String, Option<String>>) -> Option<Download> {
    let get = |key: &str| {
        args.get(key)
            .and_then(Clone::clone)
            .filter(|s| !s.is_empty())
    };
    let (url, checksum, ctype) = if let Some(url64) = get("url64bit") {
        let ctype = get("checksumtype64").or_else(|| get("checksumtype"));
        (url64, get("checksum64"), ctype)
    } else {
        (get("url")?, get("checksum"), get("checksumtype"))
    };
    let (sha256, weak) = classify_checksum(checksum, ctype, &url);
    Some(Download { url, sha256, weak })
}

/// sha256 checksums pass through; a missing or non-sha256 checksum keeps the
/// URL but yields an empty sha256 plus a weak-verification marker.
fn classify_checksum(
    checksum: Option<String>,
    ctype: Option<String>,
    url: &str,
) -> (String, Option<String>) {
    let Some(checksum) = checksum else {
        return (String::new(), Some(format!("no checksum for {url}")));
    };
    match ctype.map(|t| t.to_ascii_lowercase()) {
        Some(t) if t == "sha256" => (checksum, None),
        Some(t) => (String::new(), Some(format!("checksumType {t}"))),
        // No explicit type: 64 hex chars can only be sha256 (md5=32, sha1=40).
        None if is_sha256_hex(&checksum) => (checksum, None),
        None => (
            String::new(),
            Some(format!("checksumType unknown for {url}")),
        ),
    }
}

/// `true` for a 64-char bare-hex string (a sha256 digest).
fn is_sha256_hex(s: &str) -> bool {
    s.len() == 64 && s.chars().all(|c| c.is_ascii_hexdigit())
}

// ---------------------------------------------------------------------------
// PowerShell lexing helpers (line-oriented, quote-aware)
// ---------------------------------------------------------------------------

/// `true` for identifier bytes in variable names.
fn is_ident_byte(b: u8) -> bool {
    b.is_ascii_alphanumeric() || b == b'_'
}

/// `true` when the whole string is a plain identifier.
fn is_ident(s: &str) -> bool {
    !s.is_empty() && s.bytes().all(is_ident_byte)
}

/// Strip a trailing `#` comment, string-aware (`'...'` / `"..."` with
/// backtick escapes).
fn strip_ps_comment(raw: &str) -> String {
    let mut out = String::new();
    let mut in_single = false;
    let mut in_double = false;
    let mut escaped = false;
    for c in raw.chars() {
        if escaped {
            out.push(c);
            escaped = false;
            continue;
        }
        match c {
            '`' if in_double => {
                out.push(c);
                escaped = true;
            }
            '\'' if !in_double => {
                in_single = !in_single;
                out.push(c);
            }
            '"' if !in_single => {
                in_double = !in_double;
                out.push(c);
            }
            '#' if !in_single && !in_double => break,
            _ => out.push(c),
        }
    }
    out
}

/// Split a line into whitespace-separated tokens, keeping quoted regions
/// (with their quotes) intact.
fn tokenize_ps(line: &str) -> Vec<String> {
    let mut out = Vec::new();
    let mut cur = String::new();
    let mut in_single = false;
    let mut in_double = false;
    let mut escaped = false;
    for c in line.chars() {
        if escaped {
            cur.push(c);
            escaped = false;
            continue;
        }
        match c {
            '`' if in_double => {
                cur.push(c);
                escaped = true;
            }
            '\'' if !in_double => {
                in_single = !in_single;
                cur.push(c);
            }
            '"' if !in_single => {
                in_double = !in_double;
                cur.push(c);
            }
            c if c.is_whitespace() && !in_single && !in_double => {
                if !cur.is_empty() {
                    out.push(std::mem::take(&mut cur));
                }
            }
            _ => cur.push(c),
        }
    }
    if !cur.is_empty() {
        out.push(cur);
    }
    out
}

/// Net `{`/`}` balance of a line (outside strings).
fn line_brace_delta(line: &str) -> i32 {
    let mut delta = 0i32;
    let mut in_single = false;
    let mut in_double = false;
    let mut escaped = false;
    for c in line.chars() {
        if escaped {
            escaped = false;
            continue;
        }
        match c {
            '`' if in_double => escaped = true,
            '\'' if !in_double => in_single = !in_single,
            '"' if !in_single => in_double = !in_double,
            '{' if !in_single && !in_double => delta += 1,
            '}' if !in_single && !in_double => delta -= 1,
            _ => {}
        }
    }
    delta
}

/// Split `$name = rhs`; returns (lowercased name, trimmed rhs).
fn parse_assignment(line: &str) -> Option<(String, &str)> {
    let rest = line.strip_prefix('$')?;
    let end = rest
        .find(|c: char| !c.is_ascii_alphanumeric() && c != '_')
        .unwrap_or(rest.len());
    if end == 0 {
        return None;
    }
    let name = &rest[..end];
    let rhs = rest[end..].trim_start().strip_prefix('=')?;
    if rhs.starts_with('=') {
        return None; // `==` comparison, not an assignment
    }
    Some((name.to_ascii_lowercase(), rhs.trim()))
}

/// Lines that are inert for the install plan and may be silently skipped.
fn is_inert(line: &str) -> bool {
    let lower = line.to_ascii_lowercase();
    if lower.starts_with("param(") || lower == "param" {
        return true;
    }
    let first = lower.split_whitespace().next().unwrap_or("");
    matches!(
        first,
        "write-host" | "write-output" | "write-verbose" | "write-warning" | "write-debug"
    )
}

/// Accumulate a hashtable body opened by `@{` until its matching `}`,
/// consuming further physical lines as needed. `None` when it never closes.
fn collect_hashtable_body(after_brace: &str, lines: &[&str], i: &mut usize) -> Option<String> {
    let mut depth = 1i32;
    let mut body = String::new();
    let mut chunk = after_brace.to_string();
    loop {
        if let Some(pos) = scan_braces(&chunk, &mut depth) {
            body.push_str(&chunk[..pos]);
            return Some(body);
        }
        body.push_str(&chunk);
        body.push('\n');
        if *i >= lines.len() {
            return None;
        }
        chunk = strip_ps_comment(lines[*i].trim());
        *i += 1;
    }
}

/// Walk `chunk` adjusting `depth` for braces outside strings; returns the
/// byte position where depth reaches zero.
fn scan_braces(chunk: &str, depth: &mut i32) -> Option<usize> {
    let mut in_single = false;
    let mut in_double = false;
    let mut escaped = false;
    for (pos, c) in chunk.char_indices() {
        if escaped {
            escaped = false;
            continue;
        }
        match c {
            '`' if in_double => escaped = true,
            '\'' if !in_double => in_single = !in_single,
            '"' if !in_single => in_double = !in_double,
            '{' if !in_single && !in_double => *depth += 1,
            '}' if !in_single && !in_double => {
                *depth -= 1;
                if *depth == 0 {
                    return Some(pos);
                }
            }
            _ => {}
        }
    }
    None
}

/// Split a hashtable line on `;` outside strings.
fn split_semis(s: &str) -> Vec<&str> {
    let mut out = Vec::new();
    let mut in_single = false;
    let mut in_double = false;
    let mut escaped = false;
    let mut start = 0usize;
    for (pos, c) in s.char_indices() {
        if escaped {
            escaped = false;
            continue;
        }
        match c {
            '`' if in_double => escaped = true,
            '\'' if !in_double => in_single = !in_single,
            '"' if !in_single => in_double = !in_double,
            ';' if !in_single && !in_double => {
                out.push(&s[start..pos]);
                start = pos + 1;
            }
            _ => {}
        }
    }
    out.push(&s[start..]);
    out
}

/// Split a hashtable entry on its first top-level `=`; the key must be a
/// plain identifier.
fn split_kv(entry: &str) -> Option<(&str, &str)> {
    let mut in_single = false;
    let mut in_double = false;
    let mut escaped = false;
    for (pos, c) in entry.char_indices() {
        if escaped {
            escaped = false;
            continue;
        }
        match c {
            '`' if in_double => escaped = true,
            '\'' if !in_double => in_single = !in_single,
            '"' if !in_single => in_double = !in_double,
            '=' if !in_single && !in_double => {
                let key = entry[..pos].trim();
                let value = entry[pos + 1..].trim();
                if is_ident(key) && !value.starts_with('=') {
                    return Some((key, value));
                }
                return None;
            }
            _ => {}
        }
    }
    None
}

/// Lowercase an argument/hashtable key and fold known aliases
/// (`Url64` → `url64bit`, `Destination` → `unziplocation`).
fn normalize_key(key: &str) -> String {
    let key = key.to_ascii_lowercase();
    match key.as_str() {
        "url64" => "url64bit".to_string(),
        "destination" => "unziplocation".to_string(),
        _ => key,
    }
}

/// Index of the `)` matching the `(` at byte 0 of `s`.
fn find_matching_paren(s: &str) -> Option<usize> {
    let mut depth = 0i32;
    let mut in_single = false;
    let mut in_double = false;
    for (pos, c) in s.char_indices() {
        match c {
            '\'' if !in_double => in_single = !in_single,
            '"' if !in_single => in_double = !in_double,
            '(' if !in_single && !in_double => depth += 1,
            ')' if !in_single && !in_double => {
                depth -= 1;
                if depth == 0 {
                    return Some(pos);
                }
            }
            _ => {}
        }
    }
    None
}

/// Body of a fully single-quoted literal (with `''` unescaped to `'`).
fn full_single_quoted(s: &str) -> Option<String> {
    let body = s.strip_prefix('\'')?;
    let mut out = String::new();
    let mut chars = body.char_indices().peekable();
    while let Some((pos, c)) = chars.next() {
        if c == '\'' {
            if chars.peek().is_some_and(|&(_, n)| n == '\'') {
                out.push('\'');
                chars.next();
            } else {
                return (pos == body.len() - 1).then_some(out);
            }
        } else {
            out.push(c);
        }
    }
    None
}

/// Body of a fully double-quoted literal (backtick-escape aware; the body is
/// NOT interpolated here).
fn full_double_quoted(s: &str) -> Option<&str> {
    let body = s.strip_prefix('"')?;
    let mut escaped = false;
    for (pos, c) in body.char_indices() {
        if escaped {
            escaped = false;
            continue;
        }
        match c {
            '`' => escaped = true,
            '"' => return (pos == body.len() - 1).then(|| &body[..pos]),
            _ => {}
        }
    }
    None
}

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

    /// Minimal-but-realistic nuspec XML for `id`/`version`.
    fn nuspec_xml(id: &str, version: &str) -> String {
        format!(
            r#"<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2011/08/nuspec.xsd">
  <metadata>
    <id>{id}</id>
    <version>{version}</version>
    <title>{id}</title>
    <authors>test</authors>
  </metadata>
</package>"#
        )
    }

    /// Build a tiny in-memory `.nupkg` zip from (name, content) entries.
    fn build_nupkg(files: &[(&str, &str)]) -> Vec<u8> {
        use std::io::Write;
        let mut buf = Vec::new();
        {
            let mut zw = zip::ZipWriter::new(std::io::Cursor::new(&mut buf));
            let opts = zip::write::SimpleFileOptions::default();
            for (name, content) in files {
                zw.start_file(*name, opts).unwrap();
                zw.write_all(content.as_bytes()).unwrap();
            }
            zw.finish().unwrap();
        }
        buf
    }

    /// Parse a nupkg whose nuspec is `id`/`version` and whose install script
    /// is `ps1`, against prefix `/tc/<id>`.
    fn recipe_for(id: &str, version: &str, ps1: &str) -> ChocoRecipe {
        let nuspec = nuspec_xml(id, version);
        let bytes = build_nupkg(&[
            (&format!("{id}.nuspec"), nuspec.as_str()),
            ("tools/chocolateyInstall.ps1", ps1),
        ]);
        parse_nupkg(&bytes, Path::new(&format!("/tc/{id}"))).expect("nupkg should parse")
    }

    /// 1a. Modern splat-style zip package. Fixture modeled on the REAL
    /// terraform chocolateyInstall.ps1 (fetched from
    /// community.chocolatey.org/api/v2/package/terraform, v1.16.0-alpha
    /// series: `$packageParams = @{...}` with `Url64`, a shared
    /// `ChecksumType`, and `Install-ChocolateyZipPackage @packageParams`),
    /// trimmed of its legacy plugin-cleanup `if` blocks.
    #[test]
    fn splat_zip_package_terraform_style() {
        let ps1 = r"$ErrorActionPreference = 'Stop'

# DO NOT CHANGE THESE MANUALLY. USE update.ps1
$url = 'https://releases.hashicorp.com/terraform/1.16.0/terraform_1.16.0_windows_386.zip'
$url64 = 'https://releases.hashicorp.com/terraform/1.16.0/terraform_1.16.0_windows_amd64.zip'
$checksum = 'bbb9fe7d4b6d6f7f9160bd729d190f98bd3c8fa4845793313d72d521d768bc04'
$checksum64 = '4f36ac8f3ca338f9bec28e1fc48ce5c3de6e6bd4f11e6cfb25d3bbf65a0ef87a'

$unzipLocation = Split-Path -Parent $MyInvocation.MyCommand.Definition

$packageParams = @{
  PackageName   = 'terraform'
  UnzipLocation = $unzipLocation
  Url           = $url
  Url64         = $url64
  Checksum      = $checksum
  Checksum64    = $checksum64
  ChecksumType  = 'sha256'
}

Install-ChocolateyZipPackage @packageParams
";
        let r = recipe_for("terraform", "1.16.0", ps1);
        assert_eq!(r.id, "terraform");
        assert_eq!(r.version, "1.16.0");
        assert!(
            r.plan.is_fully_supported(),
            "{:?}",
            r.plan.unsupported_constructs()
        );
        assert_eq!(
            r.plan.resources,
            vec![ResourceSpec {
                name: "terraform".into(),
                url: "https://releases.hashicorp.com/terraform/1.16.0/terraform_1.16.0_windows_amd64.zip".into(),
                sha256: "4f36ac8f3ca338f9bec28e1fc48ce5c3de6e6bd4f11e6cfb25d3bbf65a0ef87a".into(),
                stage_to: None,
            }]
        );
        assert_eq!(
            r.plan.steps,
            vec![
                InstallStep::StageResource {
                    name: "terraform".into(),
                    dir: None
                },
                InstallStep::PrefixInstall {
                    from: ".".into(),
                    to: None
                },
            ]
        );
    }

    /// 1b. `Get-ChocolateyWebFile` splat package: the REAL jq 1.8.1
    /// chocolateyInstall.ps1 embedded VERBATIM (fetched from
    /// community.chocolatey.org/api/v2/package/jq).
    #[test]
    fn get_chocolatey_web_file_jq_verbatim() {
        let ps1 = r#"$ErrorActionPreference = 'Stop'
$toolsDir = "$(Split-Path -parent $MyInvocation.MyCommand.Definition)"

$fileFullPath = Join-Path $toolsDir "$packageName.exe"
$url = 'https://github.com/jqlang/jq/releases/download/jq-1.8.1/jq-windows-i386.exe'
$checksumType = "sha256"
$checksum = '414ec99417830178bd2f6e77fc78b34de3b12fc6b6c3229f07038c5811307124'
$url64 = 'https://github.com/jqlang/jq/releases/download/jq-1.8.1/jq-windows-amd64.exe'
$checksumType64 = "sha256"
$checksum64 = '23cb60a1354eed6bcc8d9b9735e8c7b388cd1fdcb75726b93bc299ef22dd9334'

$packageArgs = @{
    PackageName    = $env:ChocolateyPackageName
    FileFullPath   = $fileFullPath
    Url            = $url
    ChecksumType   = $checksumType
    Checksum       = $checksum
    Url64bit       = $url64
    ChecksumType64 = $checksumType64
    Checksum64     = $checksum64
}

Get-ChocolateyWebFile @packageArgs
"#;
        let r = recipe_for("jq", "1.8.1", ps1);
        assert!(
            r.plan.is_fully_supported(),
            "{:?}",
            r.plan.unsupported_constructs()
        );
        assert_eq!(
            r.plan.resources,
            vec![ResourceSpec {
                name: "jq".into(),
                url: "https://github.com/jqlang/jq/releases/download/jq-1.8.1/jq-windows-amd64.exe"
                    .into(),
                sha256: "23cb60a1354eed6bcc8d9b9735e8c7b388cd1fdcb75726b93bc299ef22dd9334".into(),
                stage_to: None,
            }]
        );
        // Web file: download/stage only, no extract-into-prefix step.
        assert_eq!(
            r.plan.steps,
            vec![InstallStep::StageResource {
                name: "jq".into(),
                dir: None
            }]
        );
    }

    /// 2. Positional `Install-ChocolateyZipPackage` form
    ///    (mixed with named checksum params).
    #[test]
    fn positional_zip_package() {
        let ps1 = r#"$toolsDir = "$(Split-Path -Parent $MyInvocation.MyCommand.Definition)"
Install-ChocolateyZipPackage 'sample' 'https://example.com/sample-1.0.0.zip' $toolsDir -Checksum '0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef' -ChecksumType 'sha256'
"#;
        let r = recipe_for("sample", "1.0.0", ps1);
        assert!(
            r.plan.is_fully_supported(),
            "{:?}",
            r.plan.unsupported_constructs()
        );
        assert_eq!(
            r.plan.resources,
            vec![ResourceSpec {
                name: "sample".into(),
                url: "https://example.com/sample-1.0.0.zip".into(),
                sha256: "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef".into(),
                stage_to: None,
            }]
        );
        assert_eq!(
            r.plan.steps,
            vec![
                InstallStep::StageResource {
                    name: "sample".into(),
                    dir: None
                },
                InstallStep::PrefixInstall {
                    from: ".".into(),
                    to: None
                },
            ]
        );
    }

    /// 3. `Install-ChocolateyPackage` (exe installer) → `Unsupported`
    ///    surfaced with the URL; the plan is not natively executable.
    #[test]
    fn install_chocolatey_package_exe_is_unsupported() {
        let ps1 = r"$packageArgs = @{
  packageName    = 'sample'
  fileType       = 'exe'
  url            = 'https://example.com/sample-setup.exe'
  silentArgs     = '/S'
  validExitCodes = @(0)
}
Install-ChocolateyPackage @packageArgs
";
        let r = recipe_for("sample", "1.0.0", ps1);
        assert!(!r.plan.is_fully_supported());
        assert!(r.plan.resources.is_empty());
        let constructs = r.plan.unsupported_constructs();
        assert_eq!(constructs.len(), 1);
        assert!(constructs[0].contains("Install-ChocolateyPackage"));
        assert!(constructs[0].contains("https://example.com/sample-setup.exe"));
    }

    /// 4. md5 `checksumType` → URL kept, sha256 left EMPTY,
    ///    weak-checksum marker surfaced as `Unsupported`.
    #[test]
    fn md5_checksum_type_weakens_verification() {
        let ps1 = r#"Install-ChocolateyZipPackage -PackageName 'sample' -Url 'https://example.com/s.zip' -Checksum 'd41d8cd98f00b204e9800998ecf8427e' -ChecksumType 'md5' -UnzipLocation "$(Split-Path -Parent $MyInvocation.MyCommand.Definition)"
"#;
        let r = recipe_for("sample", "1.0.0", ps1);
        assert!(!r.plan.is_fully_supported());
        assert_eq!(
            r.plan.resources,
            vec![ResourceSpec {
                name: "sample".into(),
                url: "https://example.com/s.zip".into(),
                sha256: String::new(),
                stage_to: None,
            }]
        );
        // Download/extract steps still present, plus the weak marker.
        assert_eq!(
            r.plan.steps,
            vec![
                InstallStep::StageResource {
                    name: "sample".into(),
                    dir: None
                },
                InstallStep::PrefixInstall {
                    from: ".".into(),
                    to: None
                },
                InstallStep::Unsupported {
                    construct: "checksumType md5".into()
                },
            ]
        );
    }

    /// 5. Missing nuspec / missing ps1 / not-a-zip → clean `RegistryError`.
    #[test]
    fn malformed_packages_error_cleanly() {
        let prefix = Path::new("/tc/sample");

        let err = parse_nupkg(b"definitely not a zip archive", prefix).unwrap_err();
        assert!(matches!(err, ToolchainError::RegistryError { .. }), "{err}");

        let no_nuspec = build_nupkg(&[("tools/chocolateyInstall.ps1", "Write-Host hi")]);
        let err = parse_nupkg(&no_nuspec, prefix).unwrap_err();
        assert!(
            matches!(&err, ToolchainError::RegistryError { message } if message.contains("nuspec")),
            "{err}"
        );

        let nuspec = nuspec_xml("sample", "1.0.0");
        let no_ps1 = build_nupkg(&[("sample.nuspec", nuspec.as_str())]);
        let err = parse_nupkg(&no_ps1, prefix).unwrap_err();
        assert!(
            matches!(&err, ToolchainError::RegistryError { message } if message.contains("chocolateyInstall")),
            "{err}"
        );
    }

    /// 6. `Install-BinFile -Name x -Path y` → `BinInstall`
    ///    (path relativized against the tools dir / prefix).
    #[test]
    fn install_bin_file_maps_to_bin_install() {
        let ps1 = r#"$toolsDir = "$(Split-Path -Parent $MyInvocation.MyCommand.Definition)"
Install-BinFile -Name 'fooctl' -Path "$toolsDir\fooctl.exe"
"#;
        let r = recipe_for("sample", "1.0.0", ps1);
        assert!(
            r.plan.is_fully_supported(),
            "{:?}",
            r.plan.unsupported_constructs()
        );
        assert_eq!(
            r.plan.steps,
            vec![InstallStep::BinInstall {
                from: "fooctl.exe".into(),
                to: Some("fooctl".into()),
            }]
        );
    }

    /// Conservatism: opaque cmdlets and unresolvable assignments surface as
    /// Unsupported (one entry per construct; an `if (...) { ... }` block folds
    /// into ONE Unsupported step) — nothing is silently swallowed.
    #[test]
    fn opaque_constructs_surface_as_unsupported() {
        let ps1 = r#"$pp = Get-PackageParameters
if (Test-Path "C:\old") {
  Remove-Item "C:\old" -Recurse -Force
}
Start-ChocolateyProcessAsAdmin 'setup.exe'
"#;
        let r = recipe_for("sample", "1.0.0", ps1);
        assert!(!r.plan.is_fully_supported());
        let constructs = r.plan.unsupported_constructs();
        assert_eq!(constructs.len(), 3, "{constructs:?}");
        assert!(constructs[0].contains("Get-PackageParameters"));
        assert!(constructs[1].starts_with("if "));
        assert!(constructs[2].contains("Start-ChocolateyProcessAsAdmin"));
    }
}