import { execFileSync } from "node:child_process";
import { existsSync, mkdtempSync, readFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import type { Desired } from "./diff.js";
import {
  type ResolvedEnv,
  resolveTemplate,
  templateKeys,
  templateRefs,
} from "./envtemplate.js";
import { loadManifest } from "./manifest.js";

// How cast authenticated (or failed to authenticate) a clone.
//
//   gh      — `gh` is installed and holds a token; borrowed as a credential
//             helper for this invocation only
//   token   — GITHUB_TOKEN / GH_TOKEN in the environment (the CI path)
//   ambient — neither; whatever git's own credential helper does, if anything
export type GitAuth = {
  source: "gh" | "token" | "ambient";
  configArgs: string[];
  env: Record<string, string>;
};

// A credential helper reads the token from the ENVIRONMENT at run time. The
// alternatives both leak it: a token in the clone URL shows up in `ps` and in
// git's own error messages, and `http.extraheader` additionally persists into
// the clone's .git/config. What lands in argv here is the literal text
// `$CAST_GIT_TOKEN`, never its value.
const TOKEN_HELPER =
  '!f() { test "$1" = get || exit 0; echo username=x-access-token; echo "password=$CAST_GIT_TOKEN"; }; f';

// `gh auth login` alone does NOT wire git's credential helper — that is
// `gh auth setup-git`, a separate act most people never run. So being logged
// into `gh` does not make `git clone` work, which is exactly the trap #13
// fell into. Borrowing gh as a helper for this one invocation closes that gap
// without mutating the operator's global git config.
const GH_HELPER = "!gh auth git-credential";

function ghHasToken(): boolean {
  try {
    // A local keyring/config read, not a network call. We never keep the
    // value — the helper re-reads it inside git.
    execFileSync("gh", ["auth", "token"], { stdio: "pipe" });
    return true;
  } catch {
    return false;
  }
}

// Resolve clone credentials INSIDE cast, in a fixed order, rather than leaving
// it to whatever the ambient git config happens to do. `credential.helper=`
// (empty) first RESETS the inherited helper list — otherwise a helper
// configured globally is consulted before ours and silently decides the
// outcome, which is the same "the connection target is implicit in a file's
// contents" problem #14 is about.
export function resolveGitAuth(
  env: NodeJS.ProcessEnv = process.env,
  hasGh: () => boolean = ghHasToken,
): GitAuth {
  if (hasGh()) {
    return {
      source: "gh",
      configArgs: [
        "-c",
        "credential.helper=",
        "-c",
        `credential.helper=${GH_HELPER}`,
      ],
      env: {},
    };
  }
  const token = env.GITHUB_TOKEN || env.GH_TOKEN;
  if (token) {
    return {
      source: "token",
      configArgs: [
        "-c",
        "credential.helper=",
        "-c",
        `credential.helper=${TOKEN_HELPER}`,
      ],
      env: { CAST_GIT_TOKEN: token },
    };
  }
  return { source: "ambient", configArgs: [], env: {} };
}

// GitHub answers "you cannot see this" with a 404, not a 403 — so a private
// repo you lack access to and a repo that does not exist are the same message
// on the wire. The failure text must not pick one; it has to name both, and
// name the credential cast actually used, or the operator debugs the wrong
// half. (The original bug reported *the repository* when the real fault was
// cast's missing credentials.)
export function cloneFailureMessage(
  orgRepo: string,
  auth: GitAuth,
  stderr: string,
): string {
  const detail = stderr.trim();
  const tail = detail
    ? ["", "git said:", ...detail.split("\n").map((l) => `  ${l}`)]
    : [];
  if (auth.source === "ambient") {
    return [
      `cannot clone ${orgRepo}: no GitHub credentials.`,
      "",
      "cast looked for, in order:",
      "  1. `gh` — not installed, or not logged in (`gh auth token` failed)",
      "  2. GITHUB_TOKEN / GH_TOKEN — not set in the environment",
      "  3. git's own credential helper — did not supply credentials either",
      "",
      "Run `gh auth login`, or set GITHUB_TOKEN. (`gh auth setup-git` also works,",
      "but cast borrows `gh` as a credential helper on its own, so logging in is",
      "enough — you do not need to change your global git config.)",
      ...tail,
    ].join("\n");
  }
  const used =
    auth.source === "gh"
      ? "`gh` (borrowed as a credential helper for this clone)"
      : "GITHUB_TOKEN / GH_TOKEN from the environment";
  return [
    `cannot clone ${orgRepo}: authenticated with ${used}, and GitHub still refused.`,
    "",
    "GitHub answers 'you cannot see this' with a 404, so this is one of:",
    `  - ${orgRepo} does not exist (check the slug)`,
    "  - it is private and this credential has no access to it",
    "  - the credential is expired, or lacks the `repo` scope",
    ...tail,
  ].join("\n");
}

export function resolveCheckout(
  orgRepo: string,
  opts: { env: string; path?: string },
): string {
  if (opts.path && opts.env === "prod") {
    // Holds for every verb that reads a manifest (apply, and now capture): a
    // feature-branch checkout must not be able to decide what prod runs, nor
    // which secret names land in prod's store.
    throw new Error(
      "refuses --path with --env prod: prod always reads the default branch",
    );
  }
  if (opts.path) return opts.path;
  const dir = mkdtempSync(join(tmpdir(), "infra-checkout-"));
  const auth = resolveGitAuth();
  try {
    execFileSync(
      "git",
      [
        ...auth.configArgs,
        "clone",
        "--depth",
        "1",
        `https://github.com/${orgRepo}.git`,
        dir,
      ],
      {
        stdio: "pipe",
        env: {
          ...process.env,
          ...auth.env,
          // Belt and braces: whatever credential path we took, git may NEVER
          // fall through to its interactive username/password prompt. GitHub
          // stopped accepting passwords there years ago, so it cannot succeed
          // — it can only hang cast, or (in the original report) hand back an
          // error about the repository that hides the real fault.
          GIT_TERMINAL_PROMPT: "0",
        },
      },
    );
  } catch (err) {
    const stderr = String((err as { stderr?: Buffer | string })?.stderr ?? "");
    throw new Error(cloneFailureMessage(orgRepo, auth, stderr));
  }
  return dir;
}

// One secret the manifest requires: the ${REF} a template names (the key it
// gets in the age store), the resource that needs it, and the env var it lands
// on there. That last pair is what `capture` reads the live value from — the
// store is keyed by REF, but the live box knows it as `resource.key`.
export type RequiredSecret = { ref: string; resource: string; key: string };

// Exactly the set of secret names an environment's manifest demands — the same
// set `apply` will later insist on, read from the same templates by the same
// parser. `capture` uses this to know what to go and fetch; nothing else has to
// be told, and nothing can be silently missed.
//
// Deliberately does NOT take a secrets map: at capture time the store does not
// exist yet. That is the whole point of the verb.
export function requiredSecrets(
  checkoutDir: string,
  envName: string,
): { required: RequiredSecret[]; generated: string[] } {
  const manifest = loadManifest(join(checkoutDir, ".infra", "manifest.yaml"));
  const envSpec = manifest.environments[envName];
  if (!envSpec) {
    throw new Error(
      `environment ${envName} not in manifest (has: ${Object.keys(manifest.environments).join(", ") || "none"})`,
    );
  }
  const required: RequiredSecret[] = [];
  const collect = (resource: string, template?: string) => {
    if (!template) return;
    const file = join(checkoutDir, ".infra", "env", template);
    if (!existsSync(file))
      throw new Error(
        `env template missing: ${file} (referenced by ${resource})`,
      );
    for (const { key, ref } of templateRefs(readFileSync(file, "utf8"))) {
      required.push({ ref, resource, key });
    }
  };
  for (const [name, app] of Object.entries(envSpec.applications)) {
    collect(name, app.env_template);
  }
  for (const [name, svc] of Object.entries(envSpec.services ?? {})) {
    collect(name, svc.env_template);
  }
  const generated = envSpec.generated_secrets ?? [];
  // A generated_secrets entry naming something no template refs is dead
  // config — and dead config in THIS list is not merely untidy, it is
  // dangerous: it reads like a guard standing over a name while standing over
  // nothing. The likeliest cause is a typo, and the consequence of the typo is
  // that the real name gets CAPTURED from the source box instead of placeheld.
  const refs = new Set(required.map((r) => r.ref));
  const dead = generated.filter((g) => !refs.has(g));
  if (dead.length > 0) {
    throw new Error(
      [
        `manifest environment ${envName}: generated_secrets names ${dead.join(", ")}, which no env template refers to`,
        "",
        `  declared:   ${generated.join(", ")}`,
        `  templates:  ${[...refs].sort().join(", ") || "(no ${...} refs at all)"}`,
        "",
        "A generated name that matches nothing guards nothing — and if this is a",
        "typo, the name it was meant to guard is being captured from the source",
        "box instead of placeheld. Fix the spelling, or drop the entry.",
      ].join("\n"),
    );
  }
  return { required, generated };
}

// What the manifest declares for an environment, as names only — no secrets, no
// age key, no store. `inventory` runs BEFORE any of those exist (that is the
// point of it: you read the box before you can possibly have adopted it), so it
// must be able to describe the manifest side without resolving a single value.
export type ManifestResource = {
  kind: "application" | "database" | "service";
  name: string;
  envKeys: string[];
};

export function manifestResources(
  checkoutDir: string,
  envName: string,
): ManifestResource[] {
  const manifest = loadManifest(join(checkoutDir, ".infra", "manifest.yaml"));
  const envSpec = manifest.environments[envName];
  if (!envSpec) {
    throw new Error(
      `environment ${envName} not in manifest (has: ${Object.keys(manifest.environments).join(", ") || "none"})`,
    );
  }
  const keysOf = (resource: string, template?: string): string[] => {
    if (!template) return [];
    const file = join(checkoutDir, ".infra", "env", template);
    if (!existsSync(file))
      throw new Error(
        `env template missing: ${file} (referenced by ${resource})`,
      );
    return templateKeys(readFileSync(file, "utf8"));
  };
  return [
    ...Object.entries(envSpec.applications).map(([name, app]) => ({
      kind: "application" as const,
      name,
      envKeys: keysOf(name, app.env_template),
    })),
    ...Object.entries(envSpec.databases ?? {}).map(([name]) => ({
      kind: "database" as const,
      name,
      envKeys: [],
    })),
    ...Object.entries(envSpec.services ?? {}).map(([name, svc]) => ({
      kind: "service" as const,
      name,
      envKeys: keysOf(name, svc.env_template),
    })),
  ];
}

export function desiredFromManifest(
  checkoutDir: string,
  envName: string,
  secrets: Record<string, string>,
): {
  desired: Desired[];
  resolvedEnvs: Record<string, ResolvedEnv>;
  backupSchedules: Record<string, { frequency: string; retention: number }>;
} {
  const manifest = loadManifest(join(checkoutDir, ".infra", "manifest.yaml"));
  const envSpec = manifest.environments[envName];
  if (!envSpec) {
    throw new Error(
      `environment ${envName} not in manifest (has: ${Object.keys(manifest.environments).join(", ") || "none"})`,
    );
  }
  const desired: Desired[] = [];
  const resolvedEnvs: Record<string, ResolvedEnv> = {};
  const backupSchedules: Record<
    string,
    { frequency: string; retention: number }
  > = {};
  const resolveEnvFile = (
    name: string,
    template?: string,
  ): ResolvedEnv | undefined => {
    if (!template) return undefined;
    const file = join(checkoutDir, ".infra", "env", template);
    if (!existsSync(file))
      throw new Error(`env template missing: ${file} (referenced by ${name})`);
    const env = resolveTemplate(readFileSync(file, "utf8"), secrets);
    resolvedEnvs[name] = env;
    return env;
  };
  for (const [name, app] of Object.entries(envSpec.applications)) {
    desired.push({
      kind: "application",
      name,
      fields: {
        git_repository: app.source.repo,
        git_branch: app.source.branch,
        build_pack: app.build.pack,
        base_directory: app.build.base_directory,
        ...(app.build.publish_directory
          ? { publish_directory: app.build.publish_directory }
          : {}),
        ...(app.build.pack === "dockercompose"
          ? {
              docker_compose_location: app.build.compose_file,
              docker_compose_domains: app.service_domains,
            }
          : {
              ...(app.port !== undefined ? { port: app.port } : {}),
              ...(app.healthcheck ? { healthcheck: app.healthcheck } : {}),
              domains: app.domains,
            }),
      },
      env: resolveEnvFile(name, app.env_template),
    });
  }
  for (const [name, db] of Object.entries(envSpec.databases ?? {})) {
    desired.push({
      kind: "database",
      name,
      fields: { type: db.type, ...(db.version ? { version: db.version } : {}) },
    });
    if (db.backup)
      backupSchedules[name] = {
        frequency: db.backup.frequency,
        retention: db.backup.retention,
      };
  }
  for (const [name, svc] of Object.entries(envSpec.services ?? {})) {
    if (svc.domains && svc.domains.length > 0) {
      // Coolify 4.1.2's service executor has no flat `domains` concept —
      // hostnames live per-container on `urls` (see serviceApiFields in
      // cli.ts) — so a manifest-declared service `domains` list is silently
      // unhonorable by apply. Warn at build time, once per run, while the
      // service name is still in scope.
      console.warn(
        `service ${name} declares domains (${svc.domains.join(", ")}), but apply cannot set them on Coolify 4.1.2 services — configure hostnames manually in the Coolify UI`,
      );
    }
    desired.push({
      kind: "service",
      name,
      // domains dropped from fields, same as database `backup` above: the
      // live side (projectLiveFields in cli.ts) can't read service domains
      // and the write side (serviceApiFields) drops them, so keeping
      // domains in fields makes every domain-bearing service diff as a
      // perpetual update. Hostnames stay a manual Coolify UI act (warned
      // above).
      fields: { type: svc.type },
      env: resolveEnvFile(name, svc.env_template),
    });
  }
  return { desired, resolvedEnvs, backupSchedules };
}