import { existsSync, readFileSync } from "node:fs";
import { join } from "node:path";
import type { Role, RoleResult, WorkflowMessage } from "@uncaged/nerve-core";
import type { SpawnError } from "@uncaged/nerve-workflow-utils";
import { cursorAgent, isDryRun, spawnSafe } from "@uncaged/nerve-workflow-utils";
import { z } from "zod";
import type { PlannerMeta } from "../planner/index.js";
import type { TesterMeta } from "../tester/index.js";
import { coderPrompt } from "./prompt.js";

export const coderMetaSchema = z.object({
  workflowName: z.string().default(""),
  attempt: z.number().default(1),
  files: z
    .object({
      indexTs: z.boolean().default(false),
      packageJson: z.boolean().default(false),
      tsconfigJson: z.boolean().default(false),
    })
    .default({ indexTs: false, packageJson: false, tsconfigJson: false }),
  lintPassed: z.boolean().default(false),
  buildPassed: z.boolean().default(false),
  lintLog: z.string().default(""),
  buildLog: z.string().default(""),
  cursorOutput: z.string().default(""),
  reason: z.string().nullable().default(null),
});

export type CoderMeta = z.infer<typeof coderMetaSchema>;

export type BuildCoderDeps = {
  nerveRoot: string;
  workflowsDir: string;
};

function formatSpawnFailure(error: SpawnError): string {
  if (error.kind === "spawn_failed") {
    return error.message;
  }
  if (error.kind === "timeout") {
    return `timeout stdout=${error.stdout.slice(0, 300)} stderr=${error.stderr.slice(0, 300)}`;
  }
  return `exit ${error.exitCode} stderr=${error.stderr.slice(0, 500)}`;
}

function scanGeneratedCodePitfalls(source: string): string[] {
  const issues: string[] = [];
  if (/\bawait\s+import\s*\(/.test(source)) {
    issues.push("Found await import() in generated workflow code");
  }
  if (/\bimport\s*\(\s*["'`]/.test(source) && !source.includes("Dynamic import required")) {
    issues.push("Found undocumented dynamic import() call");
  }
  if (!/\bexport\s+default\s+/.test(source)) {
    issues.push("Missing default export of WorkflowDefinition");
  }
  return issues;
}

async function runLintAndBuild(
  workflowDir: string,
  dry: boolean,
): Promise<{
  lintPassed: boolean;
  buildPassed: boolean;
  lintLog: string;
  buildLog: string;
  reason: string | null;
}> {
  const lintRun = await spawnSafe("pnpm", ["run", "check"], {
    cwd: workflowDir,
    env: null,
    timeoutMs: 300_000,
    dryRun: dry,
  });
  if (!lintRun.ok) {
    return {
      lintPassed: false,
      buildPassed: false,
      lintLog: formatSpawnFailure(lintRun.error),
      buildLog: "",
      reason: `lint failed: ${formatSpawnFailure(lintRun.error)}`,
    };
  }

  const lintLog = lintRun.value.stderr.trim() || lintRun.value.stdout.trim() || "(no output)";
  const tscRun = await spawnSafe("npx", ["tsc", "--noEmit"], {
    cwd: workflowDir,
    env: null,
    timeoutMs: 300_000,
    dryRun: dry,
  });
  if (!tscRun.ok) {
    return {
      lintPassed: true,
      buildPassed: false,
      lintLog,
      buildLog: formatSpawnFailure(tscRun.error),
      reason: `build failed: ${formatSpawnFailure(tscRun.error)}`,
    };
  }
  const buildLog = tscRun.value.stderr.trim() || tscRun.value.stdout.trim() || "(no output)";
  return { lintPassed: true, buildPassed: true, lintLog, buildLog, reason: null };
}

function lastMetaForRole<M>(messages: WorkflowMessage[], role: string): M | null {
  for (let i = messages.length - 1; i >= 0; i--) {
    if (messages[i].role === role) {
      return messages[i].meta as M;
    }
  }
  return null;
}

export function buildCoderRole({ nerveRoot, workflowsDir }: BuildCoderDeps): Role<CoderMeta> {
  return async (start, messages) => {
    const dry = isDryRun(start);
    const plannerMeta = lastMetaForRole<PlannerMeta>(messages, "planner");
    const previousTester = lastMetaForRole<TesterMeta>(messages, "tester");
    const attempt = messages.filter((m) => m.role === "coder").length + 1;

    if (plannerMeta === null || plannerMeta.workflowName.trim().length === 0) {
      return {
        content: "coder cannot continue: missing planner output",
        meta: {
          workflowName: "",
          attempt,
          files: { indexTs: false, packageJson: false, tsconfigJson: false },
          lintPassed: false,
          buildPassed: false,
          lintLog: "",
          buildLog: "",
          cursorOutput: "",
          reason: "missing planner output",
        },
      } satisfies RoleResult<CoderMeta>;
    }

    const wfName = plannerMeta.workflowName.trim();
    const feedback =
      previousTester !== null && previousTester.passed === false
        ? `\n\nPrevious tester failure to fix:\n${previousTester.reason}\n${previousTester.dryRunLog}\n`
        : "";

    const prompt = coderPrompt({
      workflowsDir,
      wfName,
      planMarkdown: plannerMeta.planMarkdown,
      plannerStructured: {
        workflowName: plannerMeta.workflowName,
        roles: plannerMeta.roles,
        flowTransitions: plannerMeta.flowTransitions,
        validationLoopsDesign: plannerMeta.validationLoopsDesign,
        externalDeps: plannerMeta.externalDeps,
        dataFlow: plannerMeta.dataFlow,
      },
      feedback,
      nerveRoot,
    });

    const agentRun = await cursorAgent({
      prompt,
      mode: "default",
      cwd: nerveRoot,
      env: null,
      timeoutMs: null,
      dryRun: dry,
    });

    const workflowDir = join(workflowsDir, wfName);
    const files = {
      indexTs: existsSync(join(workflowDir, "index.ts")),
      packageJson: existsSync(join(workflowDir, "package.json")),
      tsconfigJson: existsSync(join(workflowDir, "tsconfig.json")),
    };
    const missing = [
      files.indexTs ? null : "index.ts",
      files.packageJson ? null : "package.json",
      files.tsconfigJson ? null : "tsconfig.json",
    ].filter((x) => x !== null) as string[];

    if (!agentRun.ok) {
      return {
        content: `coder failed: ${formatSpawnFailure(agentRun.error)}`,
        meta: {
          workflowName: wfName,
          attempt,
          files,
          lintPassed: false,
          buildPassed: false,
          lintLog: "",
          buildLog: "",
          cursorOutput: "",
          reason: formatSpawnFailure(agentRun.error),
        },
      } satisfies RoleResult<CoderMeta>;
    }

    if (missing.length > 0) {
      return {
        content: `coder failed: missing required files (${missing.join(", ")})`,
        meta: {
          workflowName: wfName,
          attempt,
          files,
          lintPassed: false,
          buildPassed: false,
          lintLog: "",
          buildLog: "",
          cursorOutput: agentRun.value,
          reason: `missing files: ${missing.join(", ")}`,
        },
      } satisfies RoleResult<CoderMeta>;
    }

    const source = readFileSync(join(workflowDir, "index.ts"), "utf-8");
    const pitfalls = scanGeneratedCodePitfalls(source);
    if (pitfalls.length > 0) {
      return {
        content: `coder static check failed:\n${pitfalls.join("\n")}`,
        meta: {
          workflowName: wfName,
          attempt,
          files,
          lintPassed: false,
          buildPassed: false,
          lintLog: pitfalls.join("\n"),
          buildLog: "",
          cursorOutput: agentRun.value,
          reason: pitfalls.join("; "),
        },
      } satisfies RoleResult<CoderMeta>;
    }

    const check = await runLintAndBuild(workflowDir, dry);
    const passed = check.lintPassed && check.buildPassed;
    return {
      content: passed
        ? `coder PASS: lint+build ok\n\n${check.lintLog}\n\n${check.buildLog}`
        : `coder FAIL: ${check.reason ?? "unknown error"}`,
      meta: {
        workflowName: wfName,
        attempt,
        files,
        lintPassed: check.lintPassed,
        buildPassed: check.buildPassed,
        lintLog: check.lintLog,
        buildLog: check.buildLog,
        cursorOutput: agentRun.value,
        reason: check.reason,
      },
    } satisfies RoleResult<CoderMeta>;
  };
}