use std::collections::BTreeMap;

use anyhow::Result;

#[derive(Clone, Copy)]
pub(crate) struct Stat {
    /// grammar id (after grouping); what the client filters on
    pub id: &'static str,
    pub name: &'static str,
    pub color: &'static str,
    pub bytes: u64,
}

pub(crate) fn analyze(repo: &gix::Repository, tree: &gix::Tree<'_>) -> Result<Vec<Stat>> {
    fn walk(
        repo: &gix::Repository,
        tree: &gix::Tree<'_>,
        bytes: &mut BTreeMap<&'static str, u64>,
    ) -> Result<()> {
        for entry in tree.iter() {
            let entry = entry?;
            let mode = entry.mode();
            let filename = entry.filename().to_string();
            if mode.is_tree() {
                if !excluded_directory(&filename) {
                    walk(repo, &repo.find_object(entry.oid())?.try_into_tree()?, bytes)?;
                }
            } else if !mode.is_link()
                && !mode.is_commit()
                && !excluded_file(&filename)
                && let Some(language) = crate::grammar_manifest::detect(&filename)
            {
                let size = repo.find_header(entry.oid())?.size() as u64;
                *bytes.entry(group(language)).or_default() += size;
            }
        }
        Ok(())
    }

    let mut bytes = BTreeMap::new();
    walk(repo, tree, &mut bytes)?;
    let mut stats = bytes
        .into_iter()
        .map(|(language, bytes)| {
            let (name, color) = metadata(language);
            Stat { id: language, name, color, bytes }
        })
        .collect::<Vec<_>>();
    stats.sort_by(|a, b| b.bytes.cmp(&a.bytes).then_with(|| a.name.cmp(b.name)));
    Ok(stats)
}

// mirrored by looksGenerated in web/util.ts; keep them in sync
fn excluded_directory(name: &str) -> bool {
    [
        "node_modules",
        "vendor",
        "third_party",
        "third-party",
        "target",
        "dist",
        "build",
        "coverage",
        ".next",
        ".nuxt",
        ".output",
        ".yarn",
        ".gradle",
        ".terraform",
        ".dart_tool",
        ".direnv",
        ".venv",
        "venv",
        "__pycache__",
        "Pods",
        "Carthage",
        "generated",
    ]
    .iter()
    .any(|excluded| name.eq_ignore_ascii_case(excluded))
}

fn excluded_file(name: &str) -> bool {
    if [
        "Cargo.lock",
        "package-lock.json",
        "npm-shrinkwrap.json",
        "yarn.lock",
        "pnpm-lock.yaml",
        "bun.lock",
        "bun.lockb",
        "deno.lock",
        "composer.lock",
        "Gemfile.lock",
        "go.sum",
        "poetry.lock",
        "uv.lock",
        "Pipfile.lock",
        "pdm.lock",
        "flake.lock",
        "mix.lock",
        "pubspec.lock",
        "Package.resolved",
        "packages.lock.json",
        "gradle.lockfile",
        "Podfile.lock",
        "Cartfile.resolved",
    ]
    .iter()
    .any(|excluded| name.eq_ignore_ascii_case(excluded))
    {
        return true;
    }

    let name = name.to_ascii_lowercase();
    name.ends_with(".lock")
        || name.ends_with(".min.js")
        || name.ends_with(".min.css")
        || name.contains(".generated.")
        || name.contains("_generated.")
        || name.ends_with(".g.dart")
        || name.ends_with(".pb.go")
        || name.ends_with(".pb.rs")
        || name.ends_with(".pb.cc")
        || name.ends_with(".pb.h")
        || name.ends_with("_pb2.py")
        || name.ends_with(".designer.cs")
}

// mirrored by languageGroup in web/languages.ts; keep them in sync
fn group(language: &'static str) -> &'static str {
    match language {
        "tsx" => "typescript",
        _ => language,
    }
}

fn metadata(language: &'static str) -> (&'static str, &'static str) {
    match language {
        "ada" => ("Ada", "#02f88c"),
        "agda" => ("Agda", "#315665"),
        "asciidoc" => ("AsciiDoc", "#73a0c5"),
        "asm" | "x86asm" => ("Assembly", "#6e4c13"),
        "awk" => ("Awk", "#c30e9b"),
        "bash" | "zsh" => ("Shell", "#89e051"),
        "batch" => ("Batchfile", "#c1f12e"),
        "c" => ("C", "#555555"),
        "c-sharp" => ("C#", "#7355dd"),
        "caddy" => ("Caddyfile", "#22b638"),
        "capnp" => ("Cap'n Proto", "#c42727"),
        "cedar" => ("Cedar", "#958792"),
        "cedarschema" => ("Cedar Schema", "#958792"),
        "clojure" => ("Clojure", "#db5855"),
        "cmake" => ("CMake", "#da3434"),
        "cobol" => ("COBOL", "#958792"),
        "commonlisp" => ("Common Lisp", "#3fb68b"),
        "cpp" => ("C++", "#f34b7d"),
        "css" => ("CSS", "#663399"),
        "d" => ("D", "#ba595e"),
        "dart" => ("Dart", "#00b4ab"),
        "devicetree" => ("Device Tree", "#958792"),
        "diff" => ("Diff", "#958792"),
        "dockerfile" => ("Dockerfile", "#384d54"),
        "dot" => ("Graphviz (DOT)", "#2596be"),
        "elisp" => ("Emacs Lisp", "#c065db"),
        "elixir" => ("Elixir", "#6e4a7e"),
        "elm" => ("Elm", "#60b5cc"),
        "erlang" => ("Erlang", "#b83998"),
        "fish" => ("fish", "#4aae47"),
        "fsharp" => ("F#", "#b845fc"),
        "gitattributes" => ("Git Attributes", "#f44d27"),
        "gleam" => ("Gleam", "#ffaff3"),
        "glsl" => ("GLSL", "#5686a5"),
        "go" => ("Go", "#00add8"),
        "graphql" => ("GraphQL", "#e10098"),
        "groovy" => ("Groovy", "#4298b8"),
        "haskell" => ("Haskell", "#5e5086"),
        "hcl" => ("HCL", "#844fba"),
        "hlsl" => ("HLSL", "#aace60"),
        "html" => ("HTML", "#e34c26"),
        "idris" => ("Idris", "#b30000"),
        "ini" => ("INI", "#d1dbe0"),
        "java" => ("Java", "#b07219"),
        "javascript" => ("JavaScript", "#f1e05a"),
        "jinja2" => ("Jinja", "#a52a22"),
        "jq" => ("jq", "#c7254e"),
        "jsdoc" => ("JSDoc", "#958792"),
        "json" => ("JSON", "#292929"),
        "julia" => ("Julia", "#a270ba"),
        "just" => ("Just", "#384d54"),
        "kconfig" => ("Kconfig", "#958792"),
        "kdl" => ("KDL", "#ffb3b3"),
        "kotlin" => ("Kotlin", "#a97bff"),
        "lean" => ("Lean", "#958792"),
        "lua" => ("Lua", "#000080"),
        "make" => ("Makefile", "#427819"),
        "markdown" => ("Markdown", "#083fa1"),
        "matlab" => ("MATLAB", "#e16737"),
        "meson" => ("Meson", "#007800"),
        "nginx" => ("Nginx", "#009639"),
        "ninja" => ("Ninja", "#958792"),
        "nix" => ("Nix", "#7e7eff"),
        "objc" => ("Objective-C", "#438eff"),
        "ocaml" => ("OCaml", "#ef7a08"),
        "odin" => ("Odin", "#60affe"),
        "perl" => ("Perl", "#0298c3"),
        "php" => ("PHP", "#4f5d95"),
        "postscript" => ("PostScript", "#da291c"),
        "powershell" => ("PowerShell", "#012456"),
        "prolog" => ("Prolog", "#74283c"),
        "proto" => ("Protocol Buffer", "#958792"),
        "python" => ("Python", "#3572a5"),
        "query" => ("Tree-sitter Query", "#8ea64c"),
        "r" => ("R", "#198ce7"),
        "regex" => ("Regular Expression", "#009a00"),
        "rego" => ("Open Policy Agent", "#7d9199"),
        "rescript" => ("ReScript", "#ed5051"),
        "ron" => ("RON", "#a62c00"),
        "ruby" => ("Ruby", "#701516"),
        "rust" => ("Rust", "#dea584"),
        "scala" => ("Scala", "#c22d40"),
        "scheme" => ("Scheme", "#1e4aec"),
        "scss" => ("SCSS", "#c6538c"),
        "solidity" => ("Solidity", "#aa6746"),
        "sparql" => ("SPARQL", "#0c4597"),
        "sql" => ("SQL", "#e38c00"),
        "ssh-config" => ("SSH Config", "#958792"),
        "starlark" => ("Starlark", "#76d275"),
        "styx" => ("Styx", "#958792"),
        "svelte" => ("Svelte", "#ff3e00"),
        "swift" => ("Swift", "#f05138"),
        "textproto" => ("Protocol Buffer Text Format", "#958792"),
        "thrift" => ("Thrift", "#d12127"),
        "tlaplus" => ("TLA", "#4b0079"),
        "toml" => ("TOML", "#9c4221"),
        "typescript" => ("TypeScript", "#3178c6"),
        "typst" => ("Typst", "#239dad"),
        "uiua" => ("Uiua", "#958792"),
        "vb" => ("Visual Basic .NET", "#945db7"),
        "verilog" => ("Verilog", "#b2b7f8"),
        "vhdl" => ("VHDL", "#adb2cb"),
        "vim" => ("Vim script", "#199f4b"),
        "vue" => ("Vue", "#41b883"),
        "wit" => ("WebAssembly Interface Type", "#6250e7"),
        "xml" => ("XML", "#0060ac"),
        "yaml" => ("YAML", "#cb171e"),
        "yuri" => ("Yuri", "#958792"),
        "zig" => ("Zig", "#ec915c"),
        _ => (language, "#958792"),
    }
}

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

    #[test]
    fn generated_file_patterns_do_not_overreach() {
        for name in ["schema.generated.ts", "messages.pb.go", "app.min.js", "CARGO.LOCK"] {
            assert!(excluded_file(name), "expected {name} to be excluded");
        }
        for name in ["Cargo.toml", "pnpm-workspace.yaml", "src.rs", "generator.ts"] {
            assert!(!excluded_file(name), "expected {name} to be retained");
        }
    }
}