from __future__ import annotations

import argparse
from datetime import datetime, timezone
import hashlib
import json
from pathlib import Path
import subprocess
from typing import Any


REPOSITORY_ROOT = Path(__file__).resolve().parents[1]
DEFAULT_EVIDENCE_ROOT = REPOSITORY_ROOT / "artifacts" / "evidence" / "accuracy" / "P1"
DEFAULT_OUTPUT = DEFAULT_EVIDENCE_ROOT / "evidence-manifest.json"

PROGRAM_PATHS = (
    "docs/accuracy-program/00-execution-contract.md",
    "docs/accuracy-program/01-system-inventory.md",
    "docs/accuracy-program/02-data-lineage.md",
    "docs/accuracy-program/03-baseline-and-gaps.md",
    "docs/accuracy-program/04-risk-register.md",
    "docs/accuracy-program/05-metric-framework.md",
    "docs/accuracy-program/06-implementation-roadmap.md",
    "docs/accuracy-program/status.json",
    "scripts/build_accuracy_phase1_evidence_manifest.py",
    "scripts/collect_accuracy_phase1_inference_smoke.py",
    "scripts/collect_accuracy_phase1_ml_lineage.py",
    "scripts/collect_accuracy_phase1_runtime.py",
    "scripts/reproduce_accuracy_phase1_findings.py",
    "scripts/run_accuracy_phase1_baseline.py",
    "scripts/verify_accuracy_phase1_evidence.py",
    "tests/test_accuracy_phase1_baseline.py",
)


def sha256_file(path: Path) -> str:
    digest = hashlib.sha256()
    with path.open("rb") as handle:
        for chunk in iter(lambda: handle.read(1024 * 1024), b""):
            digest.update(chunk)
    return digest.hexdigest()


def role_for(path: Path) -> str:
    name = path.name.lower()
    if name.endswith(".junit.xml"):
        return "test_report"
    if name.endswith(".sql"):
        return "migration_evidence"
    if "runtime" in name or "gpu-inference" in name:
        return "runtime_evidence"
    if "lineage" in name:
        return "lineage_evidence"
    if "reproduction" in name:
        return "defect_reproduction"
    if "ruff" in name or "lint" in name:
        return "lint_evidence"
    if "test" in name or "vitest" in name or "golden-qa" in name:
        return "test_evidence"
    if path.suffix.lower() == ".json":
        return "structured_inventory"
    return "execution_log"


def record(path: Path, *, displayed_path: str, role: str) -> dict[str, Any]:
    return {
        "path": displayed_path,
        "role": role,
        "size_bytes": path.stat().st_size,
        "sha256": sha256_file(path),
    }


def git_head() -> str | None:
    result = subprocess.run(
        ["git", "rev-parse", "HEAD"],
        cwd=REPOSITORY_ROOT,
        capture_output=True,
        text=True,
        check=False,
    )
    return result.stdout.strip() if result.returncode == 0 else None


def build_manifest(evidence_root: Path, output: Path) -> dict[str, Any]:
    if not evidence_root.is_dir():
        raise FileNotFoundError(f"Evidence root does not exist: {evidence_root}")

    evidence_files = [
        path
        for path in evidence_root.rglob("*")
        if path.is_file() and path.resolve() != output.resolve()
    ]
    evidence_records = [
        record(
            path,
            displayed_path=path.relative_to(REPOSITORY_ROOT).as_posix(),
            role=role_for(path),
        )
        for path in sorted(evidence_files)
    ]

    program_records = []
    for relative in PROGRAM_PATHS:
        path = REPOSITORY_ROOT / relative
        if not path.is_file():
            raise FileNotFoundError(f"Required Phase-1 program file is missing: {relative}")
        program_records.append(record(path, displayed_path=relative, role="phase1_program"))

    return {
        "schema_version": 1,
        "generated_at": datetime.now(timezone.utc).isoformat(),
        "audited_repository_head": git_head(),
        "claim_boundary": (
            "This manifest proves retained-file identity and completeness. It does "
            "not establish model accuracy, human label acceptance, split independence "
            "or release readiness."
        ),
        "evidence_root": evidence_root.relative_to(REPOSITORY_ROOT).as_posix(),
        "evidence_file_count": len(evidence_records),
        "evidence_total_bytes": sum(item["size_bytes"] for item in evidence_records),
        "evidence_files": evidence_records,
        "program_file_count": len(program_records),
        "program_files": program_records,
    }


def main() -> int:
    parser = argparse.ArgumentParser(description="Build the immutable GeoIntel Accuracy P1 evidence manifest.")
    parser.add_argument("--evidence-root", type=Path, default=DEFAULT_EVIDENCE_ROOT)
    parser.add_argument("--output", type=Path, default=DEFAULT_OUTPUT)
    args = parser.parse_args()

    evidence_root = args.evidence_root.expanduser().resolve()
    output = args.output.expanduser().resolve()
    if output.exists():
        parser.error(f"refusing to overwrite existing evidence manifest: {output}")
    if output.parent != evidence_root:
        parser.error("--output must be directly inside --evidence-root")

    payload = build_manifest(evidence_root, output)
    output.write_text(json.dumps(payload, indent=2, sort_keys=True) + "\n", encoding="utf-8")
    print(
        json.dumps(
            {
                "status": "created",
                "output": str(output),
                "evidence_file_count": payload["evidence_file_count"],
                "program_file_count": payload["program_file_count"],
            },
            indent=2,
            sort_keys=True,
        )
    )
    return 0


if __name__ == "__main__":
    raise SystemExit(main())