/**
 * CLI command registry — the single source of truth for the gitforest
 * non-TUI command surface. See architecture-deepening-2 issue #07.
 *
 * Each command is one CommandSpec record. main() in src/index.tsx walks
 * the registry to resolve commands (by name or alias), validate flags
 * (against globalFlags ∪ command.flags, rejecting unknown ones), and
 * dispatch to the handler. renderHelp(registry) derives the help output.
 *
 * Adding a new command means adding one CommandSpec — no other file
 * needs touching for argv parsing or help.
 */

import {
  listProjects,
  showStatus,
  pullAll,
  pushAll,
  fetchAll,
  showDirty,
  initNonGit,
  createGitHubRepos,
  archiveRepos,
  listGitHubRepos,
  showUnifiedStatus,
  cloneGitHubRepos,
  showGitHubAuth,
  setupProjects,
  loginGitHub,
  logoutGitHub,
  handleConfigCommand,
  handleDirCommand,
} from "./index.ts";
import { clearCache, getCacheStats } from "../scanner/index.ts";
import type { GitforestConfig, ViewMode } from "../types/index.ts";

export interface ParsedFlags {
  [key: string]: boolean | string | undefined;
}

export interface FlagSpec {
  /** Long flag name (without leading "--"). */
  name: string;
  /** Optional short alias (single character, without leading "-"). */
  short?: string;
  /** When true, the flag takes a value argument. Defaults to false (boolean). */
  takesValue?: boolean;
  description: string;
}

export interface PositionalSpec {
  name: string;
  required: boolean;
  /** Rest = consume all remaining positionals (varargs). */
  rest?: boolean;
}

export type CommandCategory = "local" | "directory" | "github" | "setup" | "auth" | "cache";

export interface CommandRunContext {
  config: GitforestConfig;
  flags: ParsedFlags;
  positional: string[];
}

export interface CommandSpec {
  name: string;
  aliases?: string[];
  category: CommandCategory;
  summary: string;
  usage?: string;
  flags?: FlagSpec[];
  positional?: PositionalSpec[];
  run(ctx: CommandRunContext): Promise<void>;
}

// ============================================================================
// Global flags — accepted on every command in addition to its own.
// ============================================================================

export const GLOBAL_FLAGS: FlagSpec[] = [
  { name: "filter", short: "f", takesValue: true, description: "Filter projects by name/path" },
  { name: "json", description: "Output as JSON" },
  { name: "verbose", short: "v", description: "Verbose output" },
  { name: "max-depth", takesValue: true, description: "Max scan depth (for dir add/set)" },
  { name: "help", short: "h", description: "Show this help message" },
];

// ============================================================================
// Shared helpers for run() bodies
// ============================================================================

function buildCliOptions(ctx: CommandRunContext) {
  const { config, flags } = ctx;
  const filter = typeof flags["filter"] === "string" ? flags["filter"] : undefined;
  const json = !!flags["json"];
  const verbose = !!flags["verbose"];
  let maxDepth: number | undefined;
  if (flags["max-depth"]) {
    const raw = String(flags["max-depth"]);
    const parsed = /^\d+$/.test(raw) ? Number(raw) : NaN;
    if (!Number.isFinite(parsed) || parsed < 0 || parsed > 10) {
      throw new Error(`--max-depth must be an integer between 0 and 10 (got: ${flags["max-depth"]})`);
    }
    maxDepth = parsed;
  }
  return { config, filter, json, verbose, maxDepth };
}

// ============================================================================
// The registry — every command declared in one place.
// ============================================================================

export const COMMANDS: CommandSpec[] = [
  // --- Local repo commands -----------------------------------------------
  {
    name: "list",
    aliases: ["ls"],
    category: "local",
    summary: "List all local projects",
    async run(ctx) {
      await listProjects(buildCliOptions(ctx));
    },
  },
  {
    name: "status",
    aliases: ["st"],
    category: "local",
    summary: "Show status summary",
    async run(ctx) {
      await showStatus(buildCliOptions(ctx));
    },
  },
  {
    name: "dirty",
    category: "local",
    summary: "Show dirty repositories",
    async run(ctx) {
      await showDirty(buildCliOptions(ctx));
    },
  },
  {
    name: "pull",
    category: "local",
    summary: "Pull all repositories",
    async run(ctx) {
      await pullAll(buildCliOptions(ctx));
    },
  },
  {
    name: "push",
    category: "local",
    summary: "Push repositories with unpushed commits",
    async run(ctx) {
      await pushAll(buildCliOptions(ctx));
    },
  },
  {
    name: "fetch",
    category: "local",
    summary: "Fetch all remotes",
    async run(ctx) {
      await fetchAll(buildCliOptions(ctx));
    },
  },
  {
    name: "init",
    category: "local",
    summary: "Initialize git in non-git projects",
    async run(ctx) {
      await initNonGit(buildCliOptions(ctx));
    },
  },

  // --- Setup commands ----------------------------------------------------
  {
    name: "setup",
    category: "setup",
    summary: "Setup: init git + create GitHub repo + push",
    flags: [
      { name: "public", description: "Create public repos (default: private)" },
    ],
    async run(ctx) {
      await setupProjects({
        ...buildCliOptions(ctx),
        isPrivate: !ctx.flags["public"],
      });
    },
  },
  {
    name: "create-repos",
    aliases: ["create"],
    category: "setup",
    summary: "Create GitHub repos for projects without remotes",
    flags: [
      { name: "public", description: "Create public repos (default: private)" },
    ],
    async run(ctx) {
      await createGitHubRepos({
        ...buildCliOptions(ctx),
        isPrivate: !ctx.flags["public"],
      });
    },
  },
  {
    name: "archive",
    category: "github",
    summary: "Archive GitHub repositories",
    usage: "gitforest archive --yes <repo1> [repo2] ...",
    positional: [{ name: "repos", required: true, rest: true }],
    flags: [
      { name: "yes", short: "y", description: "Confirm this destructive action" },
    ],
    async run(ctx) {
      if (ctx.positional.length === 0) {
        throw new Error("Please specify repositories to archive\nUsage: gitforest archive --yes <repo1> [repo2] ...");
      }
      await archiveRepos({ ...buildCliOptions(ctx), repos: ctx.positional, yes: !!ctx.flags["yes"] });
    },
  },

  // --- GitHub commands ---------------------------------------------------
  {
    name: "github",
    aliases: ["gh"],
    category: "github",
    summary: "List repos on GitHub not cloned locally",
    flags: [
      { name: "local", description: "Show local repos only" },
      { name: "combined", description: "Show all repos (local + GitHub)" },
    ],
    async run(ctx) {
      const view: ViewMode = ctx.flags["local"]
        ? "local"
        : ctx.flags["combined"]
          ? "combined"
          : "github";
      await listGitHubRepos({ ...buildCliOptions(ctx), view });
    },
  },
  {
    name: "unified-status",
    aliases: ["ustatus"],
    category: "github",
    summary: "Show unified status (local + GitHub)",
    async run(ctx) {
      await showUnifiedStatus(buildCliOptions(ctx));
    },
  },
  {
    name: "clone",
    category: "github",
    summary: "Clone GitHub repos not yet local",
    usage: "gitforest clone [repos...]",
    positional: [{ name: "repos", required: false, rest: true }],
    flags: [
      { name: "target", short: "t", takesValue: true, description: "Target directory for clone" },
      { name: "https", description: "Use HTTPS clone URL instead of SSH" },
    ],
    async run(ctx) {
      const targetDir = typeof ctx.flags["target"] === "string" ? ctx.flags["target"] : undefined;
      await cloneGitHubRepos({
        ...buildCliOptions(ctx),
        repos: ctx.positional.length > 0 ? ctx.positional : undefined,
        targetDir,
        useHTTPS: !!ctx.flags["https"],
      });
    },
  },

  // --- Auth commands -----------------------------------------------------
  {
    name: "auth",
    category: "auth",
    summary: "Check GitHub authentication status",
    async run() {
      await showGitHubAuth();
    },
  },
  {
    name: "login",
    category: "auth",
    summary: "Login to GitHub (opens browser)",
    async run() {
      await loginGitHub();
    },
  },
  {
    name: "logout",
    category: "auth",
    summary: "Logout from GitHub",
    async run() {
      await logoutGitHub();
    },
  },

  // --- Cache commands ----------------------------------------------------
  {
    name: "cache",
    category: "cache",
    summary: "Cache management (status, clear)",
    usage: "gitforest cache [status|clear]",
    positional: [{ name: "subcommand", required: false }],
    async run(ctx) {
      const sub = ctx.positional[0];
      if (sub === "clear") {
        await clearCache();
        console.log("Cache cleared.");
      } else if (sub === "status" || sub === undefined) {
        const stats = await getCacheStats();
        console.log("Cache Statistics:");
        console.log(`  Projects cached: ${stats.projectCount}`);
        if (stats.oldestScan) {
          console.log(`  Oldest scan: ${stats.oldestScan.toLocaleString()}`);
        }
        if (stats.newestScan) {
          console.log(`  Newest scan: ${stats.newestScan.toLocaleString()}`);
        }
      } else {
        throw new Error(`Unknown cache subcommand: ${sub}\nUsage: gitforest cache [status|clear]`);
      }
    },
  },

  // --- Directory management ---------------------------------------------
  {
    name: "dir",
    aliases: ["dirs", "directories"],
    category: "directory",
    summary: "Manage configured scan directories",
    usage: "gitforest dir [list|add|remove|set] ...",
    positional: [{ name: "subcommand", required: false }, { name: "args", required: false, rest: true }],
    flags: [
      { name: "label", takesValue: true, description: "Label for directory (for dir add/set)" },
      { name: "editor", takesValue: true, description: "Editor override (for dir set)" },
    ],
    async run(ctx) {
      const label = typeof ctx.flags["label"] === "string" ? ctx.flags["label"] : undefined;
      const editor = typeof ctx.flags["editor"] === "string" ? ctx.flags["editor"] : undefined;
      const opts = { ...buildCliOptions(ctx), label, editor };
      if (ctx.positional.length === 0) {
        await handleDirCommand("list", [], opts);
      } else {
        await handleDirCommand(ctx.positional[0]!, ctx.positional.slice(1), opts);
      }
    },
  },
  {
    name: "config",
    category: "directory",
    summary: "Legacy: config subcommands (use 'dir' instead where possible)",
    usage: "gitforest config <subcommand> ...",
    positional: [{ name: "subcommand", required: true }, { name: "args", required: false, rest: true }],
    flags: [
      { name: "label", takesValue: true, description: "Label for directory (for config add-dir)" },
      { name: "editor", takesValue: true, description: "Editor override" },
    ],
    async run(ctx) {
      if (ctx.positional.length === 0) {
        throw new Error("Missing config subcommand\nUsage: gitforest config add-dir <path>");
      }
      const label = typeof ctx.flags["label"] === "string" ? ctx.flags["label"] : undefined;
      const editor = typeof ctx.flags["editor"] === "string" ? ctx.flags["editor"] : undefined;
      if (ctx.positional[0] === "add-dir") {
        await handleDirCommand("add", ctx.positional.slice(1), { ...buildCliOptions(ctx), label, editor });
      } else {
        await handleConfigCommand(ctx.positional[0]!, ctx.positional.slice(1), buildCliOptions(ctx));
      }
    },
  },
];

// ============================================================================
// Lookup + flag validation
// ============================================================================

export function findCommand(name: string): CommandSpec | undefined {
  return COMMANDS.find((c) => c.name === name || c.aliases?.includes(name));
}

/**
 * Validate parsed flags against (global ∪ command-specific) flag specs.
 * Returns a list of error strings (empty if all valid).
 */
export function validateFlags(spec: CommandSpec, flags: ParsedFlags): string[] {
  const allowed = new Set<string>([
    ...GLOBAL_FLAGS.map((f) => f.name),
    ...(spec.flags?.map((f) => f.name) ?? []),
  ]);
  const errors: string[] = [];
  for (const key of Object.keys(flags)) {
    if (!allowed.has(key)) {
      errors.push(`Unknown flag --${key} for command '${spec.name}'`);
    }
  }
  return errors;
}

/**
 * Map a short flag name to its long form by walking global + per-command specs.
 * Returns undefined if no spec declares this short.
 */
export function resolveShortFlag(short: string, spec: CommandSpec | null): string | undefined {
  for (const f of GLOBAL_FLAGS) {
    if (f.short === short) return f.name;
  }
  if (spec?.flags) {
    for (const f of spec.flags) {
      if (f.short === short) return f.name;
    }
  }
  return undefined;
}

/**
 * Return the set of all long flag names declared anywhere in the registry
 * (global + per-command). Used as a permissive check at parse time so a
 * truly-typo'd flag is caught early; precise per-command validation runs
 * later via validateFlags.
 */
export function allLongFlagNames(): Set<string> {
  const names = new Set<string>(GLOBAL_FLAGS.map((f) => f.name));
  for (const cmd of COMMANDS) {
    for (const f of cmd.flags ?? []) names.add(f.name);
  }
  return names;
}

/** Same idea for short flags. */
export function allShortFlagNames(): Map<string, string> {
  const map = new Map<string, string>();
  for (const f of GLOBAL_FLAGS) {
    if (f.short) map.set(f.short, f.name);
  }
  for (const cmd of COMMANDS) {
    for (const f of cmd.flags ?? []) {
      if (f.short) map.set(f.short, f.name);
    }
  }
  return map;
}

/** Flags that require a value argument. */
export function allFlagsTakingValue(): Set<string> {
  const names = new Set<string>();
  for (const f of GLOBAL_FLAGS) {
    if (f.takesValue) names.add(f.name);
  }
  for (const cmd of COMMANDS) {
    for (const f of cmd.flags ?? []) {
      if (f.takesValue) names.add(f.name);
    }
  }
  return names;
}

// ============================================================================
// Help rendering — derived from the registry
// ============================================================================

const CATEGORY_LABELS: Record<CommandCategory, string> = {
  local: "Local Repo Commands",
  setup: "Setup Commands",
  github: "GitHub Commands",
  auth: "Auth Commands",
  cache: "Cache Commands",
  directory: "Directory Commands",
};

const CATEGORY_ORDER: CommandCategory[] = ["local", "setup", "github", "auth", "cache", "directory"];

export function renderHelp(): string {
  const lines: string[] = [
    "",
    "gitforest - Git Repository Manager",
    "",
    "Usage:",
    "  gitforest                    Start the interactive TUI",
    "  gitforest <command> [options]",
    "",
  ];

  for (const category of CATEGORY_ORDER) {
    const cmds = COMMANDS.filter((c) => c.category === category);
    if (cmds.length === 0) continue;
    lines.push(`${CATEGORY_LABELS[category]}:`);
    for (const c of cmds) {
      const names = [c.name, ...(c.aliases ?? [])].join(", ");
      lines.push(`  ${names.padEnd(28)} ${c.summary}`);
    }
    lines.push("");
  }

  lines.push("Global options:");
  for (const f of GLOBAL_FLAGS) {
    const short = f.short ? `-${f.short}, ` : "    ";
    const valueHint = f.takesValue ? " <value>" : "";
    lines.push(`  ${short}--${f.name}${valueHint}`.padEnd(30) + ` ${f.description}`);
  }
  lines.push("  --init                   Create default config file");
  lines.push("");

  lines.push("Per-command options:");
  for (const c of COMMANDS) {
    if (!c.flags || c.flags.length === 0) continue;
    lines.push(`  ${c.name}:`);
    for (const f of c.flags) {
      const short = f.short ? `-${f.short}, ` : "    ";
      const valueHint = f.takesValue ? " <value>" : "";
      lines.push(`    ${short}--${f.name}${valueHint}`.padEnd(30) + ` ${f.description}`);
    }
  }
  lines.push("");

  lines.push("Environment:");
  lines.push("  GITHUB_TOKEN             GitHub personal access token for API access");
  lines.push("                           (Optional - run 'gitforest login' for automatic auth)");
  lines.push("");
  lines.push("Config file locations (in order of priority):");
  lines.push("  ./gitforest.config.yaml");
  lines.push("  ~/.config/gitforest/config.yaml");
  lines.push("  ~/.gitforest.yaml");
  lines.push("");

  return lines.join("\n");
}