from __future__ import annotations

import argparse
import json
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]
DOCS_DIR = ROOT / "docs"
MANIFEST_PATH = DOCS_DIR / "unit-sprite-rework-manifest.json"
AUDIT_PATH = DOCS_DIR / "unit-sprite-rework-audit.json"
DEFAULT_OUTPUT = DOCS_DIR / "unit-sprite-next-steps.md"
SPEC_BY_STEM = {
    "unit-shu-spearman": "unit-sprite-batch2-shu-spearman-spec.md",
    "unit-shu-archer": "unit-sprite-batch2-shu-archer-spec.md",
    "unit-shu-cavalry": "unit-sprite-batch2-shu-cavalry-spec.md",
    "unit-shu-strategist": "unit-sprite-batch2-shu-strategist-spec.md",
    "unit-shu-officer": "unit-sprite-batch2-shu-officer-spec.md",
}


def load_json(path: Path) -> dict:
    if not path.exists():
        raise FileNotFoundError(f"missing required file: {path.relative_to(ROOT)}")
    return json.loads(path.read_text(encoding="utf-8"))


def row_by_stem(audit: dict) -> dict[str, dict]:
    return {row["stem"]: row for row in audit.get("rows", [])}


def command_block(commands: list[str]) -> list[str]:
    return ["```powershell", *commands, "```"]


def write_report(output: Path) -> None:
    manifest = load_json(MANIFEST_PATH)
    audit = load_json(AUDIT_PATH)
    rows = row_by_stem(audit)
    approved = manifest.get("approvedBaseline", [])
    pending = manifest.get("pendingApproval", [])
    candidates = manifest.get("currentApprovalCandidate", {})
    next_after = manifest.get("nextAfterApproval", [])
    stage_counts = audit.get("stage_counts", {})

    lines = [
        "# Unit Sprite Next Steps",
        "",
        "This file is generated by `scripts/write-unit-sprite-next-steps.py`.",
        "",
        "## Current Gate",
        "",
        f"- Approved baseline units: {len(approved)}",
        f"- Pending approval units: {len(pending)}",
        f"- Queued rework units: {stage_counts.get('queued-rework', 0)}",
        f"- Manifest: `{MANIFEST_PATH.relative_to(ROOT).as_posix()}`",
        f"- Audit: `{AUDIT_PATH.relative_to(ROOT).as_posix()}`",
        "- Batch inventory boards include old queued assets; use them for inventory/regression checks, not approval.",
        "",
    ]
    if pending:
        lines.insert(-2, "- Current approval board: `docs/unit-sprite-current-approval-board.png`")
    else:
        lines.insert(-2, "- Current approval board: not generated until the next pending sample.")

    if pending:
        lines.extend(
            [
                "## Approval Blocker",
                "",
                "Do not expand to the next unit, commit, push, or deploy while these units remain pending:",
                "",
            ]
        )
        for stem in pending:
            row = rows.get(stem)
            if row:
                base = row["base"]
                lines.append(
                    f"- `{stem}`: {row['review_stage']}, base `{base['status']}`, "
                    f"battle bbox `{base.get('battle_min_width_px')}..{base.get('battle_max_width_px')} x "
                    f"{base.get('battle_min_height_px')}..{base.get('battle_max_height_px')}`"
                )
            else:
                lines.append(f"- `{stem}`: missing from audit")
        lines.append("")

    promote_commands = []
    if pending:
        unit = pending[0]
        version = candidates.get(unit, {}).get("version") if isinstance(candidates, dict) else None
        command = f"python scripts\\promote-unit-sprite-approval.py --unit {unit}"
        if version:
            command += f" --expected-version {version}"
        promote_commands.append(command)

    lines.extend(
        [
            "## Next Unit Queue",
            "",
        ]
    )
    if next_after:
        for index, stem in enumerate(next_after, start=1):
            row = rows.get(stem)
            status = "missing from audit"
            if row:
                status = f"{row['review_stage']}, base `{row['base']['status']}`, actions `{row['actions']['status']}`"
            spec = SPEC_BY_STEM.get(stem)
            spec_note = f", spec `{spec}`" if spec else ""
            lines.append(f"{index}. `{stem}` - {status}{spec_note}")
    else:
        lines.append("No queued next unit is defined in the manifest.")

    lines.extend(
        [
            "",
            "## Commands Before Approval",
            "",
            *command_block(
                [
                    "python scripts\\audit-unit-sprite-sheets.py",
                    "python scripts\\render-unit-sprite-review-boards.py",
                    "python scripts\\render-current-sprite-approval-board.py",
                    "python scripts\\check-unit-sprite-art-quality.py",
                    "python scripts\\check-unit-sprite-approval-gate.py --mode sample",
                    "python scripts\\write-unit-sprite-next-steps.py",
                    "python scripts\\check-unit-sprite-workflow-consistency.py",
                ]
            ),
            "",
            "## Commands After Approval",
            "",
            "After user approval, promote the approved unit in `unit-sprite-rework-manifest.json`, regenerate outputs, and only then use the release gate.",
            "",
            *command_block(
                [
                    *promote_commands,
                    "python scripts\\audit-unit-sprite-sheets.py",
                    "python scripts\\render-unit-sprite-review-boards.py",
                    "python scripts\\check-unit-sprite-approval-gate.py --mode release",
                    "pnpm build",
                ]
            ),
            "",
            "## First Task After Current Approval",
            "",
        ]
    )

    if next_after:
        first = next_after[0]
        spec = SPEC_BY_STEM.get(first, "")
        lines.append(f"- Start with `{first}`.")
        if spec:
            lines.append(f"- Use spec: `{spec}`.")
        lines.append("- Generate source art, assemble sheets, produce contact/GIF/before-after/scale/battle screenshots, then rerun the gates.")
    else:
        lines.append("- No first task is defined.")

    output.write_text("\n".join(lines) + "\n", encoding="utf-8")


def main() -> None:
    parser = argparse.ArgumentParser(description="Write the next-step report for sprite rework.")
    parser.add_argument("--out", type=Path, default=DEFAULT_OUTPUT)
    args = parser.parse_args()
    write_report(args.out)
    print(f"Wrote {args.out}")


if __name__ == "__main__":
    main()